Abstract: The aim of this study was to evaluate the thrombolytic effect of focused transparietal ultrasound in combination with a specific contrast agent (microbubbles) in acute cerebral ischemia. Acute cerebral ischemia was induced in 10 rats by intra-arterial clots injection. Five rats (group 1) were treated with a combination of transparietal ultrasound (probe 2 MHz, acoustic power 500 mW/cm(2)) and intravenous injection of 0.6 mL of the ultrasound contrast agent (UCA) sulfur hexafluoride. Five rats (group 2) were treated by fibrinolytic intravenous infusion (recombinant tissue plasminogen activator). Cerebral cellular energy production was determined by measuring the cellular phosphorylation using phosphorus magnetic spectroscopy before and during ischemia induction and after treatment. Measures were performed on a dedicated 2.35T magnet. The ratio phosphocreatine (P(Cr)) on inorganic phosphate (P(i)), P(Cr)/P(i), estimation of the oxidative phosphorylation metabolism and the intracellular pH (pHi) were measured in the two groups. Compared with the ischemia induction period, both treatments were associated with an increase of P(Cr)/P(i) and pHi values, respectively, +80% and +100% in group 1 (p=0.07) and +100% and +80% in group 2 (p=0.04). There was no significant difference between the two groups for the response treatment. To conclude, treatment with intravenous fibrinolytic infusion and treatment with focused ultrasound in combination with UCA seems to be equally effective in treating acute cerebral ischemia in rats. (E-mail: j.p.tasu@chu-poitiers.fr).
Abstract: OBJECTIVE: To evaluate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in the early detection of residual tumour after radiofrequency ablation (RFA) of renal tumours. METHODS: Patients referred to our institution for RFA of renal tumours prospectively underwent CEUS and computed tomography (CT) or magnetic resonance imaging (MRI) before, within 1 day and 6 weeks after treatment. Identification of residual tumour was assessed by three blinded radiologists. Reference standard was CT/MRI performed at least 1 year after RFA. RESULTS: A total of 66 renal tumours in 43 patients (median age 62 years; range 44-71.5) were studied. Inter-reader agreement (kappa value) was 0.84 for CEUS. Prevalence of residual disease was 19%. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), respectively, were as follows: 64% [confidence interval (CI) 39-84], 98% [CI 91-100], 82% [CI 52-95] and 92% [CI 83-97] on 24-h CEUS; 79% [CI 52-92], 100% [CI 94-100], 100% [CI 74-100] and 95% [CI 87-100] on 6-week CEUS; 79% [CI 52-92], 95% [CI 86-98], 79% [CI 52-92] and 95% [CI 86-98] on 24-h CT/MRI; and 100% [CI 72-100], 98% [CI 90-100], 91% [CI 62-98] and 100% [CI 93-100] on 6-week CT/MRI. CONCLUSION: CEUS has high specificity for the early diagnosis of residual tumour after renal RFA.
Abstract: The recent introduction of high-end ultrasound equipment combined with recent contrast agents provides marked improvements in the characterization of focal liver lesions as previously reported by monocentric studies. The aim of the present study was to evaluate the diagnostic performance of Contrast-Enhanced Ultrasonography (CEUS) using SonoVue as well as its medico-economic value for characterization of focal liver lesions. These nodules were not characterized on previous CT or conventional sonography. This prospective multicentric study conducted in 15 French centres found diagnostic performances similar to those reported for CT and MRI, with a concordance rate of 84.5%, sensitivity greater than 80% and specificity greater than 90% for all types of lesions. Higher acceptance was found for CEUS compared to other imaging modalities. Economical assessment based on examination reimbursment and contrast agent cost showed a lower cost for contrast ultrasound versus CT and MRI. This French multicentric study confirmed the high diagnostic value of CEUS for focal liver lesion characterization and demonstrated a lower economical impact compared to other imaging modalities such as CT and MRI.
Abstract: Recent reports have shown that imaging hard-shelled ultrasound (US) contrast agents at high mechanical indices engenders premature ventricular contractions (PVCs). We have shown that the oscillations of microbubbles next to a cell induce a mechanical pressure on its membrane resulting in the activation of stretch activated channels (SAC). The aim of this study is to demonstrate, in vivo and in vitro, the relationship between PVCs and SAC opening. Five anesthetized rats were used. PVCs were created in vivo with (1) US and a diluted solution of contrast microbubbles injected intravenously through the tail vein at a rate of 0.5 mL per min and (2) a manually induced mechanical stimulus, which consisted of stimulations by a flexible catheter introduced into the rat aorta and pushed until the left ventricle. PVCs were quantified through ECG measurements. In vitro experiments consisted of patch Clamp measurements on HL-1 heart cell line. The stimulation was carried out either manually with a glass rod or with US and microbubbles. For both in vivo and in vitro experiments, US consisted of 40-cycle waveforms at 1 MHz and peak negative pressures up to 300 kPa and exposure time varied from 1 to 2 min. We should emphasize that these parameters are different from those used in diagnostic conditions. In vivo, microbubbles and US at 300 kPa induced modification of rat's ECG while pressures below 300 kPa did not induce any PVC. US alone did not modify the rat's ECG. Similar PVCs were also created when stimulation with a catheter was applied. Regular heart beat rate was recovered immediately after the stimulation was stopped. In vitro, the mechanical stretch induced a cell membrane depolarization due to SAC opening. Similar effect was observed with US and microbubbles. The cell potential returned to its initial value when the stimulation was released. In conclusion, we presume that PVCs are generated through a cascade of events characterized by a mechanical action of oscillating microbubbles, opening of stretch activated ion channels, membrane depolarization and triggering of action potentials.
Abstract: These new recommendations are following the text published in 2004 by the group of experts of the EFSUMB that was augmented to reevaluate the indications of ultrasound contrast agents. Initially limited to focal liver lesions, new recommendations include the study of renal and pancreatic diseases, as well as vesico-ureteric reflux, blunt abdominal trauma and trans-cranial Doppler. Contrast-enhanced ultrasound improves the diagnosis of renal pseudo-tumors but does not allow characterization of solid focal masses. Its major contribution includes characterization of complex cystic masses, diagnosis of peripheral vascular disorders such as infarction and cortical necrosis, and radiofrequency ablation follow-up. It is also useful for the study of pancreatic masses visible at ultrasound in order to improve lesion visualization and characterization (adenocarcinoma and neuro-endocrine tumors), as well as for vascular staging.
Abstract: BACKGROUND: Doppler sonogram of the graft is used as a routine assessment in renal transplantation. When the resistance index (RI) equals 1, absent end-diastolic flow (AEDF) is observed; the prognostic value of AEDF is presently unknown. PATIENTS AND METHODS: Between 1988 and 1996, 342 patients received a first cadaveric kidney transplant in our ward. AEDF was observed in 30 patients who were compared with 60 controls who showed an RI < 0.75 within the first 7 days after transplantation. They were matched for year of transplantation (+/-1 year); recipient age (+/-2 years); recipient sex; and HLA antibodies (3 classes: 0%, 1-75%, >75%). The follow-up was 4 years. RESULTS: AEDF was observed at day 1 in 64%, at day 3 in 96%, and at day 7 in 28%. Recipient age, donor age, recipient sex, cold and warm ischemia durations, HLA A, B, and DR mismatches, and cytomegalovirus (CMV) status were not different between the 2 groups. Immediate graft function and 3- to 24-month creatinine levels were better in the control than the AEDF group. However, there was no difference in serum creatinine at 3 and 4 years or in patient and graft survivals during follow-up. CONCLUSIONS: AEDF observed within the first week following transplantation is associated with impaired renal functional recovery. However, whether AEDF is a prognostic marker of poor long-term graft function or survival remains to be proven.
Abstract: OBJECTIVE: To determine whether intravenous contrast ultrasound examination is superior to gray-scale or power Doppler ultrasound for discrimination between benign and malignant adnexal masses with complex ultrasound morphology. METHODS: In an international multicenter study, 134 patients with an ovarian mass with solid components or a multilocular cyst with more than 10 cyst locules, underwent a standardized transvaginal ultrasound examination followed by contrast examination using the contrast-tuned imaging technique and intravenous injection of the contrast medium SonoVue(R). Time intensity curves were constructed, and peak intensity, area under the intensity curve, time to peak, sharpness and half wash-out time were calculated. The sensitivity and specificity with regard to malignancy were calculated and receiver-operating characteristics (ROC) curves were drawn for gray-scale, power Doppler and contrast variables and for pattern recognition (subjective assignment of a certainly benign, probably benign, uncertain or malignant diagnosis, using gray-scale and power Doppler ultrasound findings). The gold standard was the histological diagnosis of the surgically removed tumors. RESULTS: After exclusions (surgical removal of the mass > 3 months after the ultrasound examination, technical problems), 72 adnexal masses with solid components were used in our statistical analyses. The values for peak contrast signal intensity and area under the contrast signal intensity curve in malignant tumors were significantly higher than those in borderline tumors and benign tumors, while those for the benign and borderline tumors were similar. The area under the ROC curve of the best contrast variable with regard to diagnosing borderline or invasive malignancy (0.84) was larger than that of the best gray-scale (0.75) and power Doppler ultrasound variable (0.79) but smaller than that of pattern recognition (0.93). CONCLUSION: Findings on ultrasound contrast examination differed between benign and malignant tumors but there was a substantial overlap in contrast findings between benign and borderline tumors. It appears that ultrasound contrast examination is not superior to conventional ultrasound techniques, which also have difficulty in distinguishing between benign and borderline tumors, but can easily differentiate invasive malignancies from other tumors.
Abstract: PURPOSE: To identify color Doppler imaging (CDI) parameters and other prognostic factors of a conversion from nonischemic to ischemic retinal vein occlusion (RVO) in a large population with a long follow-up. METHODS: This was a retrospective observational study. Data were collected for patients who had been admitted to the ophthalmologic department of the Hospital of Tours because of nonischemic central RVO (CRVO) or branch RVO (BRVO). We analyzed the relation between time until conversion into ischemic RVO and several prognostic factors of conversion, mainly vein velocities as measured by CDI. RESULTS: Analyses involved 162 patients. One year after inclusion, conversion into ischemic RVO occurred in 25.0% of the 113 CRVO and in 28.6% of the 49 BRVO cases. For CRVO, an increase of the minimal central retinal venous velocity (CRV), measured by CDI before and after treatment by hemodilution, diminished the risk of conversion into an ischemic form (p=0.048). For BRVO, an elevated maximal CRV on diagnosis was a protector (p=0.004). Age was associated with a high risk of ischemic evolution for CRVO (p=0.023) but not BRVO. Initial visual acuity was not associated with the conversion, for BRVO or CRVO. Increased retinal hemorrhages highly increased the risk of conversion both for CRVO (p<0.0001) and BRVO (p=0.010). CONCLUSIONS: Risk of ischemic evolution for BRVO and CRVO treated by isovolemic hemodilution was associated with central venous velocities. CDI might be useful for identifying risk of ischemic conversion and individualizing the follow-up of patients.
Abstract: Gaseous microemboli can arise in extracorporeal lines and devices such as dialysis machines. They are associated with severe pulmonary side effects in patients undergoing chronic hemodialysis sessions. The goal of this study was to develop a gaseous emboli trapper using ultrasound waves to remove any air bubble from the tubing system before they reach the patient. A homemade bubble trapper, developed in the laboratory, consists of a Perspex block containing a main channel connected to the tubing of a hemodialysis machine and a second subchannel positioned perpendicularly to the main one, used to trap the air microemboli. The microemboli flowing in the main channel were insonified through an acoustic window with an ultrasound wave, at a frequency of 500 kHz and with a maximal acoustic pressure of 500 kPa, generated by a single-element transducer positioned 3 cm away from the main flow. The radiation force induced by the ultrasound beam acts directly on the flowing air emboli, by pushing them into the subchannel. Two Doppler probes operating both at 2 MHz, connected to a DWL Doppler machine were placed before and after the bubble trapper to count sequentially the number of embolic events. The flow of the machine was varied between 200 mL/min and 500 mL/min. Depending on the flow velocity, the number of microembolic signals (MES) detected by the Doppler probes before and after the trapping system was identical and ranged from 5 to 150 MES/min in absence of the ultrasound irradiation. When the air bubble trapper was activated, a reduction of the number of MES, up to 70%, was achieved. Doppler recordings suggest that the circulating bubbles were either fragmented into smaller bubble fragments or directly got pushed into the second subchannel where they were collected. This simple approach using an ultrasound-based trapping system was shown to operate adequately with the current settings and can be used to filter air microemboli.
Abstract: While ultrasound is the imaging modality of choice for diagnosis of thyroid lesions, characterization remains limited and tissue diagnosis frequently is required for management. The availability of additional tools such as elastography may improve lesion characterization and direct management. MATERIALS AND METHODS: A total of 96 patients (11 males and 85 females; 58+/-24 years) referred for fine needle aspiration (FNA) of mainly solid thyroid nodules 9-32 mm in diameter underwent conventional US and elastosonography. Results on elastography were correlated with histological results from FNA and classified as follows: suspected malignant lesion, suspected benign lesion, suspicious, indeterminate. RESULTS: The nodules were classified as follows: 95 nodules were soft (classes I and II) and 13 nodules were hard (classes III and IV). No cancers were detected in class and II lesions and 6 cancers were detected in class III and IV lesions. FNA provided insufficient cellular material for diagnosis in 5 class I-II nodules and 2 class III-IV nodules. CONCLUSION: Real-time elastosonography may be a useful adjunct to conventional US in the evaluation and characterization of thyroid nodules allowing identification of patients at high risk of malignancy for whom tissue diagnosis and/or close follow-up is required.
Abstract: PURPOSE: To explore the feasability of imaging lung masses with a novel endobronchial linear-array transducer. METHOD: We used a linear-array transducer of 7 F (2.3 mm in diameter) operating at a center frequency of 10 MHz for endobronchial imaging. We used the probe in 20 subjects with suspected lung cancer to identify and measure the tumor; to asses the tumor's sonographic characteristics, bronchial wall invasion, and presence of lymph nodes; to guide a transbronchial needle aspiration (TBNA); and to evaluate potential side effects. RESULTS: In all patients, the tumor was identified and the relationship with the bronchial wall correctly evaluated through the depiction of a 3-layer wall pattern. Bronchial wall invasion was suspected in 5 patients, small adjacent lymph nodes were detected in 3 patients, and a small pleural effusion was observed close to the lung lesion in 2 patients. The linear-array probe allowed the guidance of successful TBNA with no complications. CONCLUSION: This feasibility study shows that the prototype probe can be used to depict pulmonary lesions and to guide biopsy nodes. Larger series are needed to validate its usefulness in clinical work-ups and patients management.
Abstract: Contrast agents for ultrasound imaging, composed of tiny gas microbubbles, have become a reality in clinical routine. They are extensively used in radiology for detection and characterization of various tumors and in cardiology for left ventricular opacification. Recent experimental studies showed that ultrasound waves in combination with contrast agent microbubbles increase transiently cell membrane permeability in a process known as sonoporation. This effect is thought to allow foreign molecules to enter the cell. In that context, we explored the cell membrane's responses to microbubbles' oscillations as the mechanism is not completely understood. Breast cancer cell line in combination with contrast microbubbles were used. Ultrasound was applied using a transducer of 1 MHz center frequency transmitting a 10-cycle burst of different acoustic pressures repeated every 100 mus. Patch-clamp technique in whole cell configuration was used to explore transmembrane ion exchange through the variations in membrane potential. To characterize the activated ion channels, the variations of the intracellular calcium (Ca(2+)) concentration were explored using a fluorescent marker. The results revealed that ultrasound stimulation induces a rapid hyperpolarization of cell membrane potential when the microbubble is in direct contact with the cell, but the potential returned to its initial value when ultrasound stimulation stopped. The change in cell membrane potential indicates the activation of specific ion channels and depends on the quality of microbubble adhesion to the cell membrane. Microbubbles were shown to induce a mechanical stretch activating BKca channels. Simultaneous Ca(2+) measurements indicate a slow and progressive Ca(2+) increase that is likely a consequence of BKca channels opening not a cause. These results demonstrate that microbubbles' oscillations under ultrasound activation entail modulation of cellular function and signaling by t- riggering the modulation of ionic transports through the cell membrane. Cells response to the mechanical stretch caused by gentle microbubble oscillations is characterized by the opening of BKca stretch channels and a Ca(2+) flux, which might potentially trigger other cellular responses responsible for membrane sonopermeabilization.
Abstract: Transcranial Doppler has been used previously to determine hemodynamic response to sensorial stimulation in adults but not in the neonatal period. Cerebral blood flow velocity (CBFV) was recorded in both middle cerebral arteries (MCA) and posterior cerebral arteries (PCA) in 100 premature neonates (male 56; female 44; 26 to 36 weeks gestation) from birth to 12 months. Brain development was evaluated on clinical examination. No difference in velocities was noted on prestimulation recordings from birth to 12 months. During light stimulation before six months, the CBFV was reduced (-11 +/- 6% in MCA and -13 +/- 5% in PCA compared with baseline values). After stimulation, the CBFV was increased (+6.7 +/- 3% in MCA and + 10.5 +/- 4% in PCA compared with baseline values). This study is in favor of cortex maturation in normal premature neonates at only six months. Consequently, functional transcranial Doppler technique will be helpful for the diagnosis of abnormal maturation timing in neonates with possible developmental retardation.
Abstract: Fetal heart rate (FHR) monitoring is a crucial part of monitoring at-risk pregnancies and labor. Its aim is to detect any abnormalities that might indicate acute fetal distress and a need for rapid treatment to avoid death or serious sequelae, including cerebral handicap. The use of fetal biophysical profiles in high-risk pregnancies (gravidic hypertension, in utero infection, etc.) helps to distinguish healthy fetuses from those with chronic conditions. Fetal biophysical profile scores have been developed that integrate five biophysical parameters, one of which is derived from the FHR. The major parameters detected are the rate of fetal movements, fetal tone, fetal breathing movement and amniotic fluid volume. All of those parameters except FHR are obtained by prolonged echographic observation and cannot be used routinely. We developed in this study a new multigate multitransducer pulsed Doppler system for survey of fetal behavior. Fast Fourier transform and autocorrelation function have been used for processing and analyzing ultrasonic Doppler signals generated by fetal movements. Several parameters are analyzed in each of the 12 x 5 = 60 Doppler gates: amplitude of signals reflected by moving fetal structures, velocity, direction and amplitude of displacement of fetal structure (heart, chest, limbs). From these parameters it is possible to calculate FHR and characterize fetal activity. Preliminary in vivo results obtained in 15 pregnant women (30 to 36 wk) are very encouraging but they have yet to be confirmed in future studies. These results also demonstrate the advantages of transducers designed for improved fetal movement detection. The algorithms needs to be precise enough to allow the Actifetus system to function in real time. We now have at our disposal some algorithms that succeed in quantifying FHR and fetal movements with a signal from a given sensor at a given depth. This study confirms the feasibility of monitoring fetal movements by the Actifetus system and demonstrates the importance of the characterization of fetal rhythms (and fetal behavior). The Actifetus system will serve as a new mean for studying fetal response to environment and detecting anomalies related to fetal suffering.
Abstract: New clinical applications of ultrasound contrast microbubbles extend beyond imaging and diagnosis toward therapeutic applications. Cell membrane permeability and the uptake of substances have been shown to be enhanced by microbubbles under ultrasound stimulation. However, the mechanisms of action of ultrasound-activated microbubbles are still unknown. The aim of our study was to examine how microbubbles and ultrasound interact with cells in an attempt to understand the sonoporation mechanism. The ruptured-patch-clamp whole-cell technique was used to measure membrane potential variations of a single cell. SonoVue microbubbles and mammary breast cancer cell line MDA-MB-231 were used. Ultrasound was applied using single-element transducers of 1 MHz. Microbubbles and cells were simultaneously video monitored during ultrasound exposure. Our results showed that, during sonoporation, a marked cell membrane hyperpolarization occurs (n = 6 cells) at negative pressures above 150 kPa, indicating the activation of specific ion channels while the cell and the microbubbles remain viable. The hyperpolarization was sustained for as long as the microbubbles are in a direct contact with the cell and the ultrasound waves are transmitted. Smaller acoustic amplitudes induced only mild hyperpolarization, whereas shutting off the ultrasound brings the cell membrane potential to its resting value. However, ultrasound alone did not affect the cell membrane potential. A similar hyperpolarization of the cell membrane was observed when a mechanical pressure was applied on the cell through a glass probe. In conclusion, the results demonstrate that microbubbles' oscillations under ultrasound activation entail modifications of the electrophysiologic cell activities by triggering the modulation of ionic transports through the plasmic cell membrane. However, only cells in direct contact with the microbubbles are impacted. The mechanisms involved are likely related to activation of specific channels sensitive to mechanical stresses (stretch-activated channels) and possibly nonspecific ion channels.
Abstract: BACKGROUND: In healthy patients, the narrowest diameter of the subglottic upper airway is the width of the air-column at the level of the cricoid cartilage. This diameter governs the selection of the endotracheal tube size, as excessive tube diameter may damage the tracheal mucosa leading to postextubation stridor or subglottic stenosis. Unfortunately, selecting endotracheal tube size based on height, weight, or age does not reliably lead to the proper tube. The knowledge of airway diameter, especially using a bedside noninvasive tool, could therefore be helpful in anesthesia and intensive care. METHODS: We studied 19 healthy volunteers (27 +/- 3 yr, nine females) to compare the transverse diameter of the cricoid lumen assessed by ultrasonography and magnetic resonance imaging. RESULTS: We found a strong correlation between the two techniques (r = 0.99, P < 0.05) confirmed by Bland-Altman analysis with a bias of 0.14 mm, a precision of 0.33 mm, and limits of agreement of -0.68 mm/0.96 mm. CONCLUSION: In young healthy adults, ultrasonography appeared to be a reliable tool to assess the diameter of the subglottic upper airway.
Abstract: OBJECTIVE: To assess the performance of a power doppler vascularity index in the preoperative diagnosis of ovarian malignancy. PATIENTS AND METHODS: Two successive series of adnexal masses (N=101 and N=82) were examined prospectively with power Doppler before surgical treatment. A vascularity index, called Power Doppler Index (PDI), based on the number of colored pixels, was estimated on selected frames (defined region of interest covering the entire tumor) of the tumors using an in house color-quantifying program. The first study was monocentric to test the inter- and intraobserver reproducibilities and the availability of the parameter. The second was multicentric to validate the first results. The sensitivity and specificity of PDI, resistance index (RI) and subjective visual scoring were compared using receiver operating characteristic (ROC) curves. RESULTS: Histology identified 23 malignant and 78 benign lesions in the first study and 34 malignant and 48 benign tumors in the second. PDI was considerably higher in malignant than in benign lesions (0.34+/-0.04 vs 0.12+/-0.06 (P<0.001)). Intra-observer and interobserver variability of PDI was low (intraclass correlation coefficients estimated at 0.99 and 0.98, respectively). The PDI cut-off value for differential diagnosis was set at 0.265 (26.5% of the tumor is colored) in the first study and 0.107 in the second. Sensitivity and specificity were 100% (95% CI [87.8; 100.0]) and 97.4% (95% CI [91.0; 99.7]), respectively, for PDI in the first study compared to 75% (95% CI [72.9; 90.7]) and 60% (95% CI [56.3; 92.5]) in the second study. Using logistic regression, visual Doppler scoring performed best. DISCUSSION AND CONCLUSION: The Power Doppler Index obtained using our color quantifying software has discriminating power for adnexal masses but visual Doppler scoring performs best.
Abstract: The combined use of high-end ultrasound units and sonographic contrast agents provide valuable information for lesion characterization and follow-up of patients under targeter treatments, especially oncologic patients. Early published results for liver pathology have created a place for this technique as a reference method leading to the publication of European guidelines. New oncologic applications have emerged over the last several years for lesions accessible by ultrasound with varied diagnostic value based on each target organ. Contrast-enhanced sonography is rapidly gaining ground for the follow-up of patients under targeted treatment, physical or drug induced, with major implications for the validation of concepts, and management of patients based on reliable early evaluation of therapeutic response to treatment. The purpose of this paper is to review recent advances in this field of sonographic imaging to better understand the role of ultrasound in oncologic pathology.
Abstract: Future applications of ultrasound and microbubbles extend to more than imaging applications. Over the last few years, it was reported that sonographic contrast agent effects under ultrasound, modulate transiently cell membrane permeability. This process, named sonoporation and classified as a new physical method to transfer genes or drugs, consists of using a physical energy source to modulate membrane integrity. The possibility to transfer therapeutic genes would be a new tool for gene therapy and could constitute an alternative method. After in vitro and in vivo studies presentation, the therapeutic potential of sonoporation will be investigated in this paper.
Abstract: OBJECTIVES: We investigated the potential of quantitative parametric analysis in the differential diagnosis of focal nodular hyperplasia (FNH) from other hypervascularized liver focal lesions. MATERIALS AND METHODS: Eighty-five focal liver lesions (in 83 patients) were explored using contrast-enhanced ultrasound (SonoVue and Cadence Contrast Pulse Sequencing) consisting of typical FNH (n=52), hepatocellular carcinoma (n=11), hemangioma with high flow (n=8), hypervascular metastases (n=10), and hepatocellular adenoma (n=4). QontraXt software (AMID, Italy) was used here to estimate the following parameters: maximum peak value, Tr (time corresponding to time for obtaining 63% of the plateau), beta parameter corresponding to the exponential factor, and slope corresponding to the tangent value of the first phase of enhancement. These parameters were obtained from the time-intensity curves derived from the enhancement observed in 2 regions of interest corresponding, respectively, to the whole lesion and the central region only. RESULTS: A significant statistical difference (P<0.05) was found in the values of Tr, beta, and slope between FNH and other hypervascularized lesions on both the whole lesion and central region. Among these parameters, slope appeared as the most valuable whatever the region of interest, ie, central or whole lesion (P<0.01). Central region was more accurate in the differentiation of FNH and concordant with visual characterization. CONCLUSION: Quantitative parametric curve analysis of the different hypervascularized lesions confirms the depiction of the central artery in FNH and thus could help in differentiating this specific focal liver lesion from the others.
Abstract: The purpose of this study was to assess the accuracy of Cadence Contrast Pulse Sequencing (Siemens-Acuson, CA) method with injection of SonoVue (Bracco Imaging SpA, Italy) for the detection and characterisation of focal liver lesions in comparison with a reference modality during routine use. METHODS: 138 consecutive patients (62 women, 76 men; mean age: 52 years for women and 63 years for men) corresponding to 144 examinations with 381 lesions participated in this prospective study from December 2002 to November 2003. Inclusion criteria were lesions detected by conventional US and the availability of a reference imaging examination (CT or MR imaging) within three weeks. The underlying liver lesions characterised by a reference modality (including biopsy in 29 lesions) were distributed as follows: haemangioma (n = 56), focal nodular hyperplasia (n = 27), hepatocellular carcinoma (n = 44), hepatocellular adenoma (n = 5), liver metastasis (n = 174), abscess (n = 2), cysts (n = 45), other benign lesions (n = 24) and 3 peritoneal metastases. RESULTS: A significant improvement was reported in the number of detected lesions between contrast-enhanced ultrasound and baseline ultrasonography (351 lesions versus 280 lesions, respectively, p < 0.01), whereas no significant difference was noted between contrast-enhanced ultrasound and reference imaging (351 versus 377 lesions, respectively). On the whole, contrast-enhanced ultrasound allowed a complete diagnosis in 96 % of the detected nodules with a significant improvement compared to conventional sonography in which the diagnosis was suspected in only 52 % out of these cases (p < 0.001). No significant difference was noted between contrast-enhanced ultrasound and the reference modality concerning characterisation of nodules. CONCLUSION: The present study clearly indicates that contrast-enhanced sonography using Sonovue and Cadence Contrast Pulse Sequencing allows real-time imaging with high accuracy and thus will be a competitive alternative to other modalities such as CT and MR imaging for liver imaging.
Abstract: Conventional ultrasonography of the kidney is faced by limitations due to the poor contrast of B-mode imaging for parenchymal disease and limited sensitivity of color Doppler for the detection of intracortical capillaries and deep pedicular vessels. Ultrasound contrast agents (USCAs) overcome these limitations, allowing the development of new applications for renal blood flow imaging and quantification. These improvements result from the increased acoustic response obtained from the microbubbles, as well as from the development of pulse sequences for bubble-specific imaging. In radiology, the liver has been considered as the primary target for contrast because USCAs allow both detection and characterization of focal lesions. The kidney has been less studied because USCA kinetics do not provide the same obvious potential for tumor characterization, and most clinical trials for contrast-enhanced renal imaging were conducted using color Doppler. Despite this, the kidney offers promising applications as USCAs improve the detection of abnormal microvascular and macrovascular disorders. Contrast-enhanced US may become the modality of choice for diagnosis of renal artery stenosis and detection of a perfusion deficit, as well as for characterization of indeterminate renal lesions, atypical cystic lesions, and the identification of acute pyelonephritis.
Abstract: Our objective was to detect variations of ovarian vascularization that occur in the estrus cycle of the ewe using an IV contrast agent. Five ewes were investigated using contrast-enhanced power Doppler after Sonovue injection at day 0, 3, 5, 10 and 13 of the cycle in two successive estrus cycles. Transvaginal ultrasound monitoring of each ewe was performed after a dose of Sonovue. Parameters derived from the time-intensity curves were compared. Quantification of the enhancement and wash-in period parameters changed significantly between ovaries and between the follicular and luteal periods of the cycle. Uptake time, wash-out time, total time of enhancement and area under the curve were the parameters with the smallest variation between ovaries. Wash-out time and area under the curve are two contrast parameters that did not change with cyclic changes. Thus, using these parameters in premenopausal women will allow more accurate detection of vascular modifications that may be associated with ovarian cancer.
Abstract: PURPOSE: To investigate whether dietary docosahexaenoic acid (DHA), a peroxidizable polyunsaturated omega-3 fatty acids, sensitizes rat mammary tumors to anthracyclines and whether its action interferes with tumor vascularization, a critical determinant of tumor growth. EXPERIMENTAL DESIGN: Female Sprague-Dawley rats were initiated by N-methylnitrosourea to develop mammary tumors and then assigned to a control group (n = 18), receiving a supplementation of palm oil, or to a DHA group (n = 54), supplemented with a microalgae-produced oil (DHASCO, 1.5 g/d). The DHA group was equally subdivided into three subgroups with addition of different amounts of alpha-tocopherol. Epirubicin was injected weekly during 6 weeks after the largest tumor reached 1.5 cm(2), and subsequent changes in the tumor surface were evaluated. Tumor vascularization was assessed by power Doppler sonography before and during chemotherapy. RESULTS: DHA and alpha-tocopherol were readily absorbed and incorporated into rat tissues. Epirubicin induced a 45% mammary tumor regression in the DHA-supplemented group, whereas no tumor regression was observed in the control group. In the DHA group, before chemotherapy was initiated, tumor vascular density was 43% lower than in the control group and remained lower during chemotherapy. Enhancement of epirubicin efficacy by DHA was abolished in a dose-dependent manner by alpha-tocopherol, and the same trend was observed for DHA-induced reduction in tumor vascular density. CONCLUSIONS: Dietary DHA supplementation led to a reduction in tumor vascularization before the enhancement of any response to anthracyclines, suggesting that DHA chemosensitizes mammary tumors through an inhibition of the host vascular response to the tumor.
Abstract: Today manufacturers propose echographic systems with a resolution ranging from 100 microm down to 30 microm. This requires ultrasonic frequencies ranging from 20 to 60 MHz. However, when associated with an increase in the attenuation of the wave in the media this limits the applications to superficial exploration. High frequencies also bring special technological limitations mainly in the fields of transducers, electronics, and acoustic coupling. Although high-resolution echography has long remained marginal and been used for the exploration of the skin or the anterior chamber of the eye, new powerful and easy-to-use devices have recently appeared on the market. With these new products, new applications have also appeared such as the exploration of the oral cavity or small laboratory animals (mice).
Abstract: Here we present an echographic method to withdraw amniotic fluid from pregnant rats. The method could be an alternative to the surgical amniotic fluid collection methods used currently. On day 18 of gestation, pregnant Sprague-Dawley rats underwent amniotic sac puncture by either surgical procedure or echographically guided method. This study evaluated the effect of the 2 collection procedures on parturition day, number of pups per litter, and weight of newborns compared with those of a control group without any fluid collection. These parameters did not differ statistically across groups. However, the echographically guided method did not require surgery or postsurgical recovery and was therefore advantageous from the perspective of animal use. Moreover ultrasound-guided collection allows experimental designs that require collection of multiple samples from the same animal during a single pregnancy.
Abstract: PURPOSE: To assess the value of parametric imaging during contrast-enhanced sonographic examination in the diagnosis of focal nodular hyperplasia (FNH) of the liver. MATERIALS AND METHODS: Thirty-one patients with solitary FNH underwent contrast-enhanced sonographic examination between January 2003 and June 2004 using SonoVue and a Sequoia scanner equipped with Cadence Contrast Pulse Sequencing software. Contrast enhancement from a time sequence of perfusion frames was estimated using QontraXt software, which provides quantification of perfusion parameters. From the time-intensity curves, we obtained the following parameters: peak enhancement value, Tr (time recovery corresponding to time needed to reach 63% of the peak value), beta parameter corresponding to the exponential factor, and slope corresponding to the slope of the tangent to the arterial phase of enhancement. RESULTS: Among the 4 parameters studied, the slope of the arterial phase of enhancement was the most sensitive to image the centrifugal arterial flow originating from the central portion of the lesion, whereas peak enhancement value and Tr were the most sensitive to image full enhancement of the lesion. A blinded review revealed equivalent sensitivity in the diagnosis of FNH between the interpretation of the original videoclips and that of the parametric images. CONCLUSIONS: The results of this study show that parametric imaging can be used in place of original videoclips for clinical reporting of FNH; furthermore, it could help less-experienced sonologists diagnose FNH.
Abstract: This project was designed to evaluate an ovine model for the use of contrast agent to visualize the microcirculation of normal ovaries. Intraovarian vascularization was investigated in eight ewes by using contrast-enhanced power Doppler after intravenous injection of Sonovue at five different times during each of ten normal estrous cycles. Sheep under general anesthesia underwent transvaginal B mode and power Doppler ultrasound examination of both ovaries, then received two successive doses of 5 ml of Sonovue, one dose for each ovary. Each ovary was monitored after the contrast injection, and a 3-min video clip was stored for each side. The video clip was used to derive time-intensity curves, which were then used to derive the contrast parameters. A total of 108 doses of contrast agent were used; 93% of the injections were available for contrast enhancement analysis. The optimal dose was determined on the first two sheep. Enhancement was strongest and longest with the 5-ml dose. In one sheep, enhancement of both ovaries remained weak irrespective of the period of the cycle. No adverse side effects of Sonovue were seen in the sheep. Contrast injection improved visualization of ovarian microcirculation by 248% (95% confidence interval [CI], 210 to 285%) for 74.2 sec (95% CI, 68.2 to 80.2 sec). Ovaries on the side of ovulation had a stronger enhancement compared with the ovary with no ovulation (368% versus 175%, P < 0.001), but the enhancement time was the same. We concluded that the sheep is an excellent animal model to illustrate microcirculation enhancement by using Sonovue to demonstrate ovarian vascular changes.
Abstract: OBJECTIVE: To assess the performance of a power Doppler vascularity index in the preoperative diagnosis of ovarian malignancy. METHODS: Adnexal masses (n = 101) were examined prospectively with power Doppler ultrasonography before surgical treatment. The tumor vascularity index (power Doppler index, PDI) was determined by quantification of the number of pixels in a defined region of interest according to the formula: number of colored pixels/(total number of pixels minus the number of pixels in the fluid or avascular areas). It was estimated on selected frames of the tumors using an in-house color-quantifying program added to MATLAB 6.0 software. Inter- and intraobserver reproducibilities of PDI assessment were evaluated. Intratumoral blood flow velocity waveforms were obtained to determine the lowest resistance index (RI). A subjective visual score of power Doppler signals in the tumor was used to classify it as having low, moderate or high vascularity. The discriminatory ability of this score was compared to that of RI and PDI measurement. RESULTS: Histology identified 23 malignant and 78 benign lesions. The PDI was considerably higher in malignant than in benign lesions (0.34 +/- 0.04 vs. 0.12 +/- 0.06; P < 0.001). The intra- and interobserver variabilities of PDI were low (intraclass correlation coefficients of 0.99 and 0.97, respectively). The PDI cut-off value to differentiate malignant from benign tumors was set at 0.265 (26.5% of the tumor being colored). Using this cut-off, sensitivity and specificity were 100% (95% CI, 87.8-100.0) and 97.4% (95% CI, 91.0-99.7) compared to 78.3% (95% CI, 56.3-92.5) and 83.1% (95% CI, 72.9-90.7) for RI (cut-off value of 0.53) and 78.3% (95% CI, 56.3-92.5) and 94.9% (95% CI, 87.4-98.6) for visual scoring. Logistic regression demonstrated that PDI was the best parameter for differentiating between malignant and benign tumors. CONCLUSION: The power Doppler vascularity index obtained using customized color quantifying software has high diagnostic value in discriminating between benign and malignant adnexal masses.
Abstract: An original strategy is proposed to minimize the impact of respiratory motion on hepatic contrast-enhanced ultrasound studies. It is based on the a posteriori triggering of dynamic image sequences. It was tested on perfusion studies acquired with a high temporal resolution (8 images s-1) to enable parametric imaging. A respiratory component was first estimated by independent component analysis. The estimation of the local minima and maxima of this curve enabled us to select two subsets of frames, corresponding to the end-of-inspiration plane and to the end-of-expiration plane. Both subsets were simultaneously analysed using factor analysis of medical image sequences. This method identified the main contrast uptake kinetics and their associated localizations. The global strategy was validated firstly on a simulated study and then applied to 11 patients' studies. In both cases, the frame selection was judged relevant and a necessary preliminary step before applying methods of parametric imaging. In conclusion, the a posteriori gating method that is proposed is a first step towards local quantification of hepatic contrast-enhanced ultrasound studies.
Abstract: OBJECTIVES: To evaluate feasibility of real-time contrast enhanced ultrasound in renal disease. MATERIALS AND METHODS: Eighteen patients (sex-ratio=1: mean age 62.3 +/-18.1 years) presenting with several renal diseases were enrolled in the present study. Real time contrast enhanced sonography was performed using an ultrasound dedicated system Esatune (Esaote, Firenze, Italy) with a very low mechanical index (MI<0.1) and a dedicated contrast software CnTI after bolus injection of 2.4 ml Sonovue (Bracco, Milan, Italy). Detection, characterization and extension of renal masses as well as inflammatory and ischemic lesions were evaluated. The results were compared to those obtained by reference method such as contrast-enhanced CT-Scan or MRI. RESULTS: This preliminary study gave some valuable results compared to baseline sonography: marked improvement in tumor delineation or internal microvasculature, detection of venous extension, improvement in cystic mass characterization. Diagnosis confidence was improved and reached 83% when diagnosis concordance with reference modality was improved by 50%. CONCLUSION: These preliminary results show that real-time contrast enhanced sonography could improve detection and characterization of renal masses by a complete assessment or arterial phase. Further studies are required to confirm these first results with possible advantages for the diagnosis of renal affections.
Abstract: INTRODUCTION: Transcranial pulsed Doppler sonography with or without imagery is used in the acute phase of ischemic stroke in order to define stroke mechanism and intracranial hemodynamic consequences. STATE OF ART: This non-invasive low-cost investigation can be undertaken rapidly, within 10 minutes if guided by focal symptomatology. It detects middle cerebral artery stenosis in >or=50 p. cent of cases with a sensitivity between 75 and 90 p. cent, comparatively with conventional angiography, and middle cerebral artery occlusion with 90 p. cent sensitivity. When a temporal acoustic window is lacking, intravenous injection of a contrast agent allows good visualization of the intracranial vessels and the circle of Willis, in two-third of cases. Moreover, transcranial Doppler data have good prognostic value and facilitate analysis of recanalization after thrombolytic therapy. CONCLUSION: Beside its diagnostic and prognostic interest, transcranial Doppler sonography using a 2 MHz frequency appears to have therapeutic impact by favoring the thrombolysis process. Future developments may include early and prolonged insonation of patients suffering from stroke.
Abstract: Uterine artery embolization (UAE) is a successful and safe treatment for symptomatic leiomyomas. However, rare complications such as premature menopause and uterine necrosis can arise because of embolization of non-target tissues. We studied the feasibility of using contrast-enhanced sonography with intravenous SonoVue just before, during and after complete occlusion of both uterine arteries. In a patient with multiple, large, symptomatic leiomyomas, contrast-enhanced imaging established that the UAE was technically successful and that myometrial vascularity was not reduced. Our case suggests that ultrasound contrast agents may have a role in monitoring UAE and thus may help prevent ischemic complications. Further studies are required to confirm this.
Abstract: The recent introduction of high quality scanners and contrast agents for ultrasound deeply modifies diagnosis strategy in focal liver lesions by using validated criteria. Non-linear imaging methods using low mechanical index (MI<0.2) and second generation contrast agents allow real-time continuous imaging with concomitant limitation in background tIssue signal and also in agent collapse for a high quality contrast imaging giving dramatic improvement in detection and characterization of lesions. Interpretation is based on the presence of contrast agent within the lesion or not (hyper-, hypo- or isosignal) and the delay after injection (arterial, portal or parenchymal or late phase) as previously used by non-ultrasound methods. This allows an easy differentiation of benign from malignant lesions. Moreover, this allows complete characterization in 85 to 95% of all focal liver lesions and 75% in hepatocellular carcinomas. Those results markedly improve ultrasound accuracy compared to conventional sonography and so put contrast-enhanced sonography among recommended non-invasive imaging methods for focal liver lesions with changes in diagnostic strategy according to the lesion type and actual place of US methods. It is recommended to use contrast ultrasound methods in cancer staging for an optimal detection of liver metastases as well as in characterization of lesions detected during conventional sonography with a consecutive decrease of cost-diagnosis ratio.
Abstract: Doppler has been used for many years for cardiovascular exploration in order to visualize the walls and anatomical or functional diseases. The use of ultrasound contrast agents makes it possible to improve ultrasonic information. Thus, harmonic imaging is a powerful tool for characterizing pathologies by their vascularity. However, images are buried in noise. We present an approach for noise reduction and structural features enhancement based on nonlinear anisotropic diffusion, coupled with fuzzy clustering segmentation to delineate liver pathologies.
Abstract: The widespread use of modern imaging modalities has led to an increase in the frequency of detecting coincidental focal liver lesions (cysts, haemangiomas, focal nodular hyperplasia, adenoma, focal fatty sparing and infiltration) in patients with no symptoms of liver disease. A positive diagnosis is needed to avoid overinvestigation or protracted follow-up. The limitations of conventional sonography have led to the use of other imaging modalities and invasive or costly procedures such as CT, MRI or biopsy. The availability of real-time contrast-enhanced ultrasound imaging (CEUS) has changed the strategy in the characterization of such lesions without inconvenience for the patient. Cadence contrast pulse sequencing (CPS) gives strong contrast signals as well as simultaneous acquisition of conventional scans for a perfect match of these two images. In our personal experience, in comparison with reference imaging, CPS with SonoVue has differentiated benign from malignant lesions in all cases and has accurately characterized 96% of lesions. These results are slightly better than those reported in the literature, probably because of the higher sensitivity of CPS in detecting bubbles, whether flowing or stationary, and also because of the possibility of matching simultaneously recorded contrast and conventional images which reinforces confidence in lesion assessment. The high diagnostic value of CEUS makes this method a candidate to be considered a reference imaging modality for incidental lesions.
Abstract: PURPOSE: To assess the value of combined conventional and contrast-material enhanced sonography for the characterization of focal liver lesions. MATERIALS AND METHODS: Simultaneous imaging with grey scale and contrast enhanced US was performed in 90 patients following Levovist injection (Schering, Berlin, Germany) using the "Agent Detection Imaging" method (ADI, Siemens-Acuson, Mountain View, USA). US scanning was performed at least 4 minutes after contrast injection with review of both grayscale and contrast enhanced modes. Results for detection and characterization of lesions were compared to the selected gold standard imaging modality (CT or MRI). RESULTS: Final diagnoses included: 20 normal examinations, 41 patients with metastases, 6 patients with hepatocellular carcinoma, 13 patients with hemangioma, 6 patients with other benign lesions, 4 patients with cysts and 6 patients with two types of lesions. Delayed phase contrast enhanced US allowed diagnosis of all lesions except for one metastasis and all hepatocellular carcinomas. While the diagnosis of hepatoma could not be confirmed, the features suggested a malignant etiology. For 7 patients with metastases, more lesions were detected at ADI (4.9 lesions) than at conventional US (1.1 lesion). For 3 patients, CT showed more lesions than ADI US (3.3 versus 1.6 lesions). The accuracy of ADI US for differentiating between benign and malignant lesions was 98.7% compared to 49.6% for conventional US (p<0.001). The total number of lesions detected at ADI US was higher (p<0.01) than at conventional US and not significantly different from that obtained by the gold standard reference methods. Complete characterization was achieved in 92.2% of cases with ADI US compared to 59.2% with conventional US (p<0.001). CONCLUSION: Contrast-material enhanced US combined with conventional US markedly improves the diagnostic accuracy of US in terms of lesion detection and characterization.
Abstract: OBJECTIVE: To investigate the potential efficacy of real-time contrast-enhanced power Doppler sonography in the differentiation of benign and malignant adnexal masses in a pilot study. METHODS: Before surgical treatment, adnexal masses were prospectively evaluated with power Doppler sonography before and after injection of a contrast agent. Real-time postinjection sequences were computerized with time-intensity analysis software to determine an enhancement curve and contrast parameters. The intraobserver and interobserver reproducibilities of these criteria were assessed on a subsample. These contrast parameters were compared between benign and malignant tumors using logistic regression. Sensitivity and specificity were used to compare contrast parameters with sonographic and Doppler variables. RESULTS: Ninety-nine women were included, for a total of 101 adnexal masses. There were 23 cases of ovarian malignancies and 78 benign adnexal lesions. Our procedure had excellent intraobserver and interobserver reproducibility, with an average intraclass correlation coefficient of 0.92. The time before enhancement and intensity ratio did not reliably differentiate between the benign and malignant masses. Washout times and areas under the curves were significantly greater in ovarian malignancies than in other benign tumors (P < .001), leading to sensitivity estimates between 96% and 100% and specificity estimates between 83 and 98%. Contrast parameters had slightly higher sensitivity and slightly lower specificity when compared with transvaginal sonographic variables of the resistive index and serum cancer antigen 125 levels. CONCLUSIONS: Contrast-enhanced power Doppler imaging may easily and precisely discriminate benign from malignant adnexal lesions. Larger studies are needed to determine the appropriate use and benefits of this new procedure.
Abstract: PURPOSE: Changes in tumor vascularization may be involved in tumor regression after anticancer treatments. We therefore studied the relationship between tumor vascularization and tumor response according to treatment by irradiation (RT), epirubicin (EPI), or antiangiogenic agent TNP-470 in a nitrosomethyl-ureas-induced rat mammary tumor model by measuring the changes in tumor blood flow using high-frequency Power-Doppler sonography. EXPERIMENTAL DESIGN: Mammary tumors were induced in female Sprague-Dawley rats by a single s.c. injection of nitrosomethyl-ureas. After tumor areas reached 2 cm(2), the animals received four weekly injections of epirubicin (EPI group), or a single fraction of 18 Gy (RT group), or six injections of TNP-470 within 12 days (TNP group), or both (RT combined with TNP-470, RT+TNP group). Power-Doppler sonography quantification of tumor vascularization (PDI) was performed before and 12 days after initiation of treatment. Tumor shrinkage was later evaluated and compared with the early changes in PDI values. RESULTS: Compared with the control group, EPI induced an arrest in tumor growth. A similar effect was obtained with TNP-470. There was a decrease in tumor area after RT, but administration of TNP-470 combined with RT did not further enhance this effect. Changes in tumor area paralleled changes in PDI in the EPI group. Furthermore, changes in PDI 7 days after RT were associated with further tumor change in the RT groups, whereas they were independent of the antitumor effect of TNP-470. CONCLUSIONS: Changes in functional tumor vascularization evolution appeared to be closely associated with tumor regression after anticancer treatment.
Abstract: OBJECTIVE: To investigate the changes occurring in the vascularization of tumors during irradiation, we used a model of autochthonous mammary tumors in rats and assessed early vascular changes after irradiation by power Doppler sonography. METHODS: Mammary tumors were induced in 24 female Sprague Dawley rats by a single subcutaneous injection of N-nitroso N-methyl urea. After tumor areas reached 1 cm2, the animals received a single fraction of 18-Gy radiation or intraperitoneal saline injection. Power Doppler sonographic quantification of detected vessels was performed 1 day before irradiation and 7 days after the use of a power Doppler index of 5 different tumor imaging planes. Final tumor shrinkage was compared with early changes in the power Doppler index. Not all tumors regressed in a similar fashion. Radiosensitive tumors were defined as tumors with a greater than 50% decrease in baseline area 28 days after irradiation, whereas radioresistant tumors were tumors with a less than 50% decrease in baseline area. Statistical analysis was performed by the Mann-Whitney U test. RESULTS: Tumor area changes were similar in radioresistant and radiosensitive tumors 7 days after irradiation (-41% and -35%, respectively; P > .05, not significant), whereas reduction in the power Doppler index was significantly greater in radiosensitive tumors (mean value, -63%) than in radioresistant tumors (mean value, -12%) (P = .001). Late tumor regrowth was correlated with day 7 power Doppler index changes (P = .009). A 40% reduction in the power Doppler index at day 7 distinguished 8 of 9 radiosensitive tumors and 8 of 9 radioresistant tumors (P = .003). CONCLUSIONS: This study suggests that early changes in tumor perfusion as assessed by power Doppler sonography after tumor irradiation may precede the long-term tumor regression.
Abstract: PURPOSE: The purpose of this study was to evaluate the rate of leiomyoma recurrence after uterine artery embolization (UAE) for symptomatic uterine leiomyomas. MATERIALS AND METHODS: A prospective study of UAE of uterine leiomyomas has been ongoing at the authors' hospital since 1997. The recurrence rate was assessed in June 2002. Vascular access was obtained via the right common femoral artery and free-flow embolization was performed with use of 150-250- micro m polyvinyl alcohol particles and an absorbable particle sponge. Follow-up included clinical and ultrasound (US) examinations at 3, 6, and 12 months, and once per year thereafter. RESULTS: Eighty-five UAE procedures were performed between January 1997 and June 2000. Five patients were lost to follow-up. Median follow-up was 30 months (range, 2-57 months). There were six immediate failures: one technical failure, three cases of concomitant disease (one case of endometrial cancer and two cases of adenomyosis), and two cases of large subserosal leiomyomas. There were eight late failures or recurrences: one case of leiomyoma progression, seven cases of new leiomyomas. Mean time to recurrence was 27.4 months. CONCLUSIONS: Although UAE is an effective primary treatment for leiomyomas, this study recorded a recurrence rate of 10% at just more than 2 years. Clinical and US examinations are needed before UAE to exclude pedunculated submucosal leiomyomas and cancers, and must be repeated for more than 2 years after UAE to monitor patients' progress. Longer follow-up and more events are needed to define risk factors for recurrence.
Abstract: Atherosclerosis is a major health problem in industrialised countries. Several studies have suggested an association exists between certain microorganisms and the development of atherosclerosis. The aim of the study presented here was to assess the presence of viral or bacterial DNA in carotid atherosclerotic lesions. Nucleic acids were extracted from 18 carotid atherosclerotic lesions that had been collected surgically. Polymerase chain reaction was used to screen for specific genomic DNA from Chlamydia pneumoniae, cytomegalovirus and herpes simplex virus types 1 and 2. An original approach, based on the amplification by PCR of conserved bacterial 16S rDNA nucleotide sequences was also used to detect any bacterial species. The amplification product was identified by sequencing. Chlamydia pneumoniae, cytomegalovirus and herpes simplex 2 DNA were not detected in any of the samples. Herpes simplex 1 DNA was detected in 3 of the 18 samples. Genes encoding bacterial 16S rRNA were amplified and sequenced in eight atherosclerotic lesions. DNA sequences were identified by comparison with sequences registered in the GenBank database. These eight carotid atherosclerotic lesions were shown to contain several bacterial species belonging to human flora or the environment. The exact role of these microorganisms in the genesis or development of the atherosclerotic lesions remains unclear, but they may increase the inflammatory process or be an epiphenomenon.
Abstract: Many Doppler imaging studies have been performed in recent years in a large number of ocular disorders because of improvements in the Doppler equipment used for detecting and measuring the low blood-flow velocities that are a requisite for the quantitative evaluation of blood flow in the orbital vessels. The ophthalmic artery, central retinal artery and vein, posterior ciliary arteries, and the superior ophthalmic vein can be easily identified using color Doppler sonography. The changes in local blood flow in these vessels assessed by spectral analysis pulsed Doppler sonography have been used to characterize and to obtain new insights into different nontumoral vascular disorders including carotid artery stenosis, central retinal vein occlusion, giant cell arteritis, glaucoma, diabetes, fistulas, and tumoral processes of the eye and orbit. Our experience has confirmed the important role of Doppler sonography in the assessment of subclinical changes in the vascular bed, in the understanding of different processes, for following up after specific treatments, and for determining the long-term prognosis of these various conditions.
Abstract: Pelvic sonography is the gold standard for diagnosis of ovarian masses. Only 2% of adnexal masses or malignant or bordeline tumors. Does Doppler US improve the diagnostic accuracy of sonography? The purpose of this article is to review current data and identify what areas still require further evaluation with regards to Doppler characterization of adnexal masses. It has been shown that Doppler evaluation of the ovary and cyst or tumor improves the diagnostic accuracy of US to differentiate between benign and malignant lesions. Hemodynamic data collected from pulsed Doppler imaging and Doppler energy vascular mapping have been shown to improve the characterization of malignant lesions. These data improve the accuracy of B-mode US combined with clinical evaluation and CA125 measurement. Nonetheless, the sensitivity and specificity values are between 85-90%, with few missed malignancies, but several false positive results. Useful Doppler data include the resistive index and the central intratumoral location of vascular flow. The use of 3D US with computer post-processing as well as sonographic contrast agents could provide additional information, but these techniques have not yet been validated. All suspicious adnexal lesions should be evaluated by an experienced sonographer and include discriminatory parameters to distinguish between benign and malignant lesions.
Abstract: Color Doppler US of the urinary tract is still facing a few limitations including, for B-mode imaging, the detection of small lesions, and, for color Doppler, the detection of low flow. Ultrasound contrast agents (USCA) improve these two limitations and allow the development of new functional applications for renal blood flow quantification. This improvement results from an increased acoustic response obtained from the microbubbles, as well as from the development of pulse sequencing and signal processing that led to the concept of specific ultrasound sequences. Most of the clinical indications of contrast-enhanced ultrasonography remain to be validated with the improved detection of the non linear response. USCA improve the detection of abnormal micro and macrovascular disorders of the kidney, particularly for the detection and the characterization of renal artery stenosis, as well as for the visualization of renal infarction. This technique showed potentials for the study of renal masses, especially atypical cystic lesions. Among the remaining indications, the detection of reflux and testicular torsion are the most promising.
Abstract: The recent introduction of high-end ultrasound equipments combined with the introduction of contrast agents provides marked improvements in liver imaging for the detection and the characterization of focal lesions. Previous imaging methods were based on high acoustic power and demonstrated improved detection of focal liver lesions. However, good and reliable results were difficult to achieve due to limited number of sweeps, as most of the microbubbles were destroyed within one pass. Non linear imaging methods at low acoustic power allowed great advances in the characterization by limiting signal from background tissue as well as agent collapse allowing continuous imaging starting from the time of contrast injection until complete disappearance of the agent. Contrast-enhanced imaging of the liver follows conventional sonography performed with high standards for detection and localization of lesions using multiple sweeps. Then targeted acquisition is performed for specific lesion characterization after a second contrast injection. Interpretation is based on the presence or not of microbubbles within the lesion (hyper-, hypo- or isosignal) and the delay from injection (arterial, portal or parenchymal or late phase). A well-recognized semiology is reported in this paper. Based on these criteria, sensitivity and specificity are close to those reported with other modalities with accuracy 85-95% for focal liver lesions and 75% for hepatocellular carcinomas. Those results markedly improve ultrasound accuracy compared to conventional sonography, and so put contrast-enhanced sonography among recommended non-invasive imaging methods for focal liver lesions with changes in diagnostic strategy.
Abstract: Ultrasound contrast agents have been used for many many years in cardiology. Their application in other fields is more recent, related to the availability of agents that can pass through the pulmonary circulation. Physical properties of contrast microbubbles are closely bound to their gas content, shell composition, frequency of ultrasound beam, pulse repetition frequency, acoustic power and wave phase. Specific ultrasound sequences have to be used to adequately exploit microbubble-specific interactions with the ultrasound beam. The aim of this paper is to review physical properties of ultrasound contrast agents, present imaging sequences developed for optimal use of these contrasts and general applications.
Abstract: Significant advances have been recently introduced into various fields of technology, taking advantage of the use of new piezoelectric materials and the large diffusion of broadband transducers. Various types of modulation may be applied to the pulse characteristics, using single pulse, multipulse or multiline techniques, and resulting in improved spatial resolution and better penetration. Non-linear imaging uses the harmonics component, which is generated by tissues or by contrast agents. Different modalities can be used to separate harmonics from fundamental bands from the received signal. New Doppler modes have been developed, whereas grey-scale flow imaging allows the simultaneous imaging of blood flow and tissues. Compounding techniques improve the contrast resolution of tissues and reduce artefacts. If 3D techniques are now currently available, real-time 4D imaging has been recently introduced. Elastographic imaging is still under evaluation, but promising clinical results have been shown. Recent release of the DICOM specification has made the full integration of ultrasound to the PACS systems easier. All these advances indicate that the contribution and potential of ultrasound in patient management is still growing.
Abstract: OBJECTIVES: To evaluate sonographic features following uterine artery embolization and to assess using ultrasound the efficacy of embolization as the primary treatment of fibroids. DESIGN: Fifty-eight women (mean age, 44.5 years; range, 33-65 years) suffering from symptoms due to fibroids (menometrorrhagia, bulk-related symptoms, pelvic pain) were followed-up after uterine artery embolization by ultrasound examination at 3 months, 6 months, 1 year and 2 years with assessment of volume and vascularization of fibroids as well as uterine vascularization. RESULTS: Fifty-eight patients were examined at 3 months, 46 at 6 months, 36 at 1 year and 19 at 2 years. Most patients were improved or free of symptoms at 3 months (90%), 6 months (92%) and 1 year (87%) and all monitored patients were free of symptoms at 2 years. Clinical failure of treatment occurred in only two cases (3%). Progressive significant reduction in fibroid size with reference to the baseline was demonstrated during follow-up from 3 months (-29%) to 24 months (-86%). Absence of intrafibroid vessels was observed in all except three cases as early as 3 months, whereas perifibroid vessels persisted in 21 cases. No changes in uterine vascularization or uterine artery resistance were noted. CONCLUSIONS: Uterine artery embolization is a valuable endovascular method for the treatment of fibroids, resulting in marked reduction in fibroid size and disappearance of intrafibroid vessels without reduction in uterine vascularization which is well depicted by sonography.
Abstract: This study was designed to evaluate high-frequency power Doppler (PDS) and to quantify treatment-induced changes in an experimental autochthonous mammary tumour model in rats. A total of 13 rats with N-methyl, N-nitroso urea-induced mammary tumours were split into three courses; 6 rats were treated with epirubicin, 3 received a placebo injection and 4 had irradiation of their tumour with a direct electron beam using a single dose of 18 Gy. In all groups, treatment began when the tumour area reached at least 1 cm(2) and was preceded by the first power Doppler sonography study of the tumour (Echo #1). Echo #2 was carried out in the middle of the placebo or epirubicin treatment (after 3 weeks) or 7 days after irradiation in the irradiated group. Echo #3 was carried out at the end of placebo or epirubicin treatment or 28 days after irradiation. Then colour pixel density (CPD) and vascularity index (VI) were quantitated. Intraobserver and interobserver variability of the CPD and VI quantitation was low (r = 0.99 and 0.97, respectively, for intraobserver and interobserver variability of the CPD values). The monitoring of CPD and VI showed an increase with time during the observation period. No increase in CPD or VI was observed in treated mammary tumours (p < 0.01). Power Doppler sonography quantitation of angiogenesis is reproducible, noninvasive and feasible in this in vivo breast cancer model. The monitoring of angiogenesis according to different treatments is feasible in real-time. Further studies are needed to investigate the predictive value of CPD and VI on sensitivity of mammary tumours to anticancer treatment.
Abstract: BACKGROUND: Selective embolization is an effective and reputedly safe method of managing pregnancy-related bleeding. However, we report an ischemic uterine necrosis after arterial embolization. CASE: The patient had heavy postpartum bleeding treated by embolization of the uterine arteries using polyvinyl alcohol particles (diameter 150-250 and 300-600 microm) and gelatin sponge pledgets. Her postoperative recovery was complicated by menorrhagia and pelvic pain. Because of the persistent menorrhagia and risk of infection, a hysterectomy was performed. Histopathology of the hysterectomy specimen revealed massive ischemic myometrial necrosis. CONCLUSION: This complication is most likely related to the small size of the particles used. In the management of postpartum bleeding by arterial embolization, the material of choice is gelatin sponge pledgets, and the use of small particles should be avoided.
Abstract: BACKGROUND/AIM: Retinal vein occlusion (RVO) is one of the most frequent ocular vascular diseases and leads to severe vision impairment. Colour Doppler imaging (CDI) is the first method which allows distinct evaluation of arterial and venous velocities in RVO. CDI is valuable for diagnosis of RVO and shows the effects of isovolaemic haemodilution. Patients with RVO were monitored by CDI for 1 year in order to clarify venous and arterial involvement in the pathogenesis of this disease. METHODS: Patients with RVO were monitored prospectively for 1 year with clinical examinations, fluorescein angiography, and CDI every 3 months. 102 adults referred for RVO for less than 2 months were enrolled. Unaffected eyes were used as control. The maximum systolic and diastolic flow velocities and the resistance index (RI) were measured in the central retinal artery (CRA) and the maximum and minimum blood flow velocities in the central retinal vein (CRV). RESULTS: During the year of observation, branch retinal vein occlusion (BRVO), ischaemic central retinal vein occlusion (CRVO), and non-ischaemic CRVO had a distinct pattern of venous velocity changes. BRVO had a similar profile to that observed in controls. Venous velocities were continuously lower in central forms, with the lowest values in ischaemic occlusion. In contrast, a brief decrease in arterial diastolic velocity was observed in ischaemic CRVO at presentation, correlated with arteriovenous passage time on fluorescein angiography, but with rapid normalisation. CONCLUSIONS: CDI findings were correlated with the type of RVO at all times during follow up. CDI showed persistent impairment of central venous velocity in CRVO whereas there was a fast initial values recovery of the arterial velocity. These results using CDI show strong evidence of a primary venous mechanism in RVO.
Abstract: We report the case of a woman who presented a single liver lesion with no evidence of specific findings at Doppler US, CT, nuclear studies and MRI to suggest angiomyolipoma. The final diagnosis was confirmed at anatomopathology and immunohistochemistry which demonstrated positive anti-HMB 45 aspect.
Abstract: PURPOSE: Hypoxic-ischemic injury induces early changes in cerebral energy that later lead to the presence and extension of brain damage and subsequently to severe neurodevelopmental impairments such as the dyskinetic form of cerebral palsy, which is associated with damage to the striatum. The purpose of the current study was to evaluate the viability of D2 receptors in the perinatal period using I-123 iodobenzamide brain SPECT and to correlate this with early neurologic status. METHODS: After obtaining informed parental consent, 12 full-term neonates with hypoxic-ischemic events were included. I-123 iodobenzamide brain SPECT was performed 1 week after birth, corresponding to a gestational age of 39.2+/-1.7 weeks. Images were acquired using a brain-dedicated gamma camera 1 hour after intravenous injection of 30 MBq (0.8 mCi) I-123 iodobenzamide. Magnetic resonance images (T2 weighted sequence: repetition time/echo time: 2,000/30 to 150) of the brains of the same neonates were acquired on the same day. RESULTS: The right and left striatum:cerebellum activity ratios were between 1.28 and 2.25, with the greatest concentration of I-123 iodobenzamide occurring in the striatum area. A tendency of the striatum:cerebellum ratio to decrease was observed as the severity of the perinatal hypoxic-ischemic event increased despite striatal hypersignal on magnetic resonance imaging in only two neonates. CONCLUSIONS: This study, which confirms that I-123 iodobenzamide could be used in the neonatal period, shows the biochemical maturation of D2 receptors as early as 1 week after birth and also suggests the deleterious effect of perinatal hypoxic-ischemic events on D2 receptors.
Abstract: BACKGROUND: Vertebrobasilar (VB) strokes appear to have the same causes as carotid strokes. Obstructive lesions of proximal vertebral arteries probably occur in about 30% of stroke patients. PURPOSE: Our aim was to assess the validity of color Doppler sonography compared to selective intra-arterial angiography in the quantification of proximal vertebral artery stenoses. MATERIALS AND METHODS: A prospective blind study of 316 vertebral arteries was undertaken between 1996 and 1998. One hundred and fifty-eight patients with cerebrovascular disorders without cerebral hemorrhage were studied consecutively by frequency or amplitude color Doppler flow imaging and intra-arterial angiography. The lesions were quantified by morphological and hemodynamic criteria and classified into 6 groups: 0% 207 arteries; 1-29% 32 arteries; 30-49% 29 arteries; 50-69% 13 arteries; 70-99% 23 arteries; 100% 12 arteries. RESULTS: Ten of the 12 occlusions were identified, the 2 false-negatives were due to 2 revascularized vessels. Moderate stenoses (<50%) were differentiated from tight stenoses (>50%) using hemodynamic criteria. The majority of false-negative stenoses (38) in the different groups were related to intrathoracic or very deep origin of the artery, anechogenic stenosis or a tortuous vessel. Stenoses greater than 70% were diagnosed in 71% of cases with a specificity of 99%. The kappa value was 0.80. CONCLUSION: Duplex sonography should be proposed first in VB attacks or stroke to detect and quantify vertebral artery stenoses for surgery and angioplasty.
Abstract: PURPOSE: To quantify liver blood flow using US contrast agents and to evaluate arterial and portal changes in control patients and patients with liver metastases. MATERIALS AND METHODS: Twenty eight patients were included in this study, 8 controls (M0) and 20 patients with liver metastases from colon carcinoma (M+). Hepatic blood flow from hepatic artery and portal vein were determined using quantification of enhancement after contrast injection using Power Doppler US. The ratio of enhancement rise from artery and vein allows calculation of Contrast Enhanced Doppler Perfusion Index (CEDPI) as previously described for Doppler Perfusion Index (DPI). RESULTS: A significant difference was noted for CEDPI between controls (0.49 +/- 0.07) and liver with metastases (0.70 +/- 0.12). CONCLUSION: This functional method of evaluation of liver blood flow was easy to perform, and would be valuable for early detection of overt micro-metastases before anatomical changes observed by conventional imaging. This is helpful for accurate staging of colon carcinoma.
Abstract: 123I-Iodolisuride has high specific affinity for binding on dopamine D2 receptors in the striatum and has been used in a few single photon emission computed tomography (SPECT) studies of extrapyramidal disorders. The diagnosis of Parkinson's disease (PD) is very difficult in the first 5 years of evolution, with 15-25% false positive diagnoses. The aim of this study was therefore to determine the value of iodolisuride SPECT in discriminating Parkinson's from the most frequent Parkinson-plus syndromes (PPS). Seventeen patients with an extrapyramidal syndrome had a SPECT examination 1 h after injection of 180-185 MBq of 123I-iodolisuride. They were followed under dopaminergic treatment for at least 2 years. After 2 years, they were separated in two groups according to specific clinical criteria and sensitivity to dopaminergic treatment: nine patients had PD (age = 59.8+/-8.8 years; Hoehn and Yahr = 1.8+/-0.7; evolution = 4.3+/-3 years) and eight had PPS (age = 71.6+/-7.3 years; Hoehn and Yahr = 2.9+/-2.0; evolution = 4.1+/-1.5 years). The binding potential of iodolisuride in the striatum was assessed by considering the striatum (S)/occipital lobe (O) ratio at the pseudo-equilibrium 1 h after injection. The S/O ratio was statistically different between PD and PPS (1.97+/-0.3 vs. 1.65+/-0.2 (P<0.02)). Iodolisuride SPECT could differentiate both groups with a sensitivity of 88.8% and a specificity of 75%. Iodolisuride is a good specific D2 receptor ligand for SPECT and complements specific clinical criteria for the diagnosis of Parkinson's disease and differentiation between different extrapyramidal disorders.
Abstract: B-Flow is a new imaging technique which uses General Electric's Digitally Encoded Ultrasound technology to provide direct visualization of blood echoes in grey-scale imaging. This allows simultaneous imaging of blood flow and vessel walls with a high frame rate and high spatial resolution without information on velocity and direction. This promising technique which improves early detection of vascular disease could modify our routine practice in a near future.
Abstract: Carotid stenosis is the most frequently factor involved in stroke. The diagnosis of these lesions in routinely based on ultrasonic examination which allows to detect the carotid stenoses which were essentially atheromatous. B-mode evaluates the fine echostructure of plaques and Doppler helps to quantify the degree of stenosis using direct and indirect hemodynamic criteria. Echography with the help of color Doppler imaging identifies the site of stenosis in order to determine the degree of stenosis as a percentage of normal carotid area. Moreover echography is an essential method to appreciate the surface as well as the echostructure of the carotid lesion which have to be taking into account for a well-adapted therapy. The maximal velocities determined at the tight site of the lesion, the spectral changes downstream the stenosis and the hemodynamic changes observed upstream and downsteam of the carotid stenosis allow a precise quantification of this stenosis. The information obtained using sonographic methods (including 2 direct hemodynamic criteria, 2 indirect hemodynamic criteria and, if possible, a B-mode assessment of the area) are essential to appreciate the neurological risk in these patients.
Abstract: PURPOSE: We assessed early hemodynamic characteristics of various types of retinal vein occlusion using color Doppler imaging and spectral analysis. METHODS: We measured the maximum systolic and diastolic blood flow velocities and the resistance index (RI) in the central retinal artery and the maximum and minimum blood flow velocities in the central retinal vein of affected eyes and contralateral unaffected eyes in 102 adults (63 men and 39 women; mean age, 61 +/- 14.6 years) who presented with retinal vein occlusion. Sixty-three control subjects (27 men and 36 women; mean age, 50 +/- 22.1 years) were also investigated. RESULTS: No significant differences in hemodynamic characteristics were found between the control subjects' eyes and the patients' unaffected eyes. In the 18 cases of ischemic central retinal vein occlusion, the mean diastolic arterial flow velocity (p = 0.005) and venous flow velocity (p < 0.04) were lower and the mean RI was higher (p = 0. 0002) in the affected eyes than in the unaffected contralateral eyes. In the 51 cases of nonischemic central retinal vein occlusion, the mean diastolic arterial flow velocity (p < 0.0001) and venous flow velocity (p < 0.0001) also were lower and the mean RI (p < 0.0001) was higher in the affected eyes than in the unaffected contralateral eyes. These variables were different in the ischemic versus nonischemic types of central retinal vein occlusion. In the 33 cases of branch retinal vein occlusion, no significant differences were observed in arterial or venous blood flow velocities in the affected versus unaffected eyes. The mean RI in the affected eyes was significantly higher (p = 0.009) in patients with central versus branch retinal vein occlusion. CONCLUSIONS: These results suggest that previous arterial disorders were not involved in the pathogenesis of central retinal vein occlusion in these patients. The findings also support the value of Doppler imaging and spectral analysis in the diagnosis and evaluation of retinal vein occlusion and confirm the involvement of arterial flow in venous occlusion.
Abstract: OBJECTIVE: To verify the occurrence of natural variations in thigh and abdominal subcutaneous fat thickness related to the phases of the menstrual cycle, to assess the value of ultrasonography as a reliable method for monitoring subcutaneous fat thickness changes and to evaluate their amplitudes. METHODS: This study included 10 women (19-39 years) who menstruated regularly. None had used oral contraceptives or slimming products during the 3 months prior to the study. At cycle day 2 (CD2), CD6, CD14, CD22, CD27 and CD30 days (CD0: beginning of menstruation), the subjects were submitted to: (1) measurement of weight and thigh perimeters, (2) measurements of thigh and abdomen subcutaneous fatty tissue thickness on B-mode images acquired at 10 MHz. A protocol was designed to guarantee a reproducible repositioning during the whole time course of the study and ultrasound examinations (US) were always performed by the same trained person to avoid inter-examiner variability. RESULTS: Subcutaneous fat thicknesses decreased during the first half of the cycle and reached their lowest values at day 22 (-2.0% for the thighs; -3.3% for the abdominal region). Both thigh and abdomen subcutaneous fat reached their maximum thicknesses during menstruation with respective increases of +2.2 and +4.0%. The observed cyclic amplitude variations in the subcutaneous adipose tissue thickness accounted for 7.3% for the abdominal region and 4.1% for the thighs. CONCLUSION: Variations in adipose tissue thickness during the menstrual cycle could be quantified and monitored by US. The thickness of the thigh and abdominal hypodermis was more important during menstruation and decreased in mid-cycle with a minimum occurring 1 week after ovulation.
Abstract: OBJECTIVE: The purpose of this study was to analyze the technical features of uterine artery embolization and to evaluate the effectiveness of this method as the primary treatment of uterine leiomyomas in a series of 58 patients monitored by clinical and sonographic examinations. SUBJECTS AND METHODS: Fifty-eight women (age range, 33-65 years; mean age, 44.5 years) with symptoms caused by uterine leiomyomas (abnormal bleeding, bulk-related symptoms, pelvic pain) were included in this prospective study. We performed embolization with a single catheter using the single-femoral artery approach, injection of particles (150-250 mm), and an absorbable gelatin sponge. Postprocedural pain was assessed using a visual analog scale. Systematic follow-up included clinical and sonographic examinations at 3 months for 58 patients, at 6 months for 46 patients, at 1 year for 27 patients, and at 2 years for seven patients. RESULTS: Embolization was performed without problems in 84% of the patients. Post-procedural pain control was excellent in 90% of the patients. In most patients, symptoms were improved or had resolved at 3 months (90%), 6 months (92%), and 1 year (93%), and all patients were symptom-free at 2 years. Clinical failure of treatment occurred in only two patients (3%). Progressive reduction in leiomyoma size was revealed during sonographic follow-up, and new leiomyomas were seen in one patient at 2 years. CONCLUSION: Uterine artery embolization is an endovascular method for the treatment of uterine leiomyomas that is clinically effective in most patients and that induces a progressive reduction in the size of the largest leiomyomas.
Abstract: BACKGROUND: Doppler ultrasound methods were used during haemodialysis sessions for the detection of microemboli and determination of their origin. METHODS: A 2-MHz ultrasound probe (Multidop X(4) DWL((TM))) was used to assess the number of microembolic signals (MES) in the subclavian vein downstream from the arteriovenous fistula before the dialysis session and over two periods of 15 min at the beginning and end of haemodialysis sessions in 25 patients without previous cardiovascular disease. A similar probe was used during in vitro studies to detect MES at different sites in the dialysis machine (before and downstream from the blood pump, and before and downstream from the air trap). RESULTS: No MES were detected during in vivo studies before haemodialysis sessions. MES were registered in all patients (100%) at the beginning and end of the haemodialysis procedure at an average of 12.7+/-9 and 16. 7+/-11.5 signals/min respectively. The average intensity of MES was 19.2+/-5.0 dB and 19.4+/-3.9 dB respectively. No MES were detected on the arterial line during in vitro studies. In contrast, 19+/-6 MES/min were detected after the blood pump, 13+/-4.2 before the air trap, and 16.5+/-5.5 thereafter. CONCLUSIONS: In all patients, MES were recorded during haemodialysis sessions in the drainage vein from arteriovenous fistulae. The results of in vitro studies indicate that MES are formed by the blood pump of the haemodialysis machine. The intensity of the MES suggests that they correspond to synthetic particles or microbubbles, which are not detected by the air trap. The final destination of these microbubbles will be assessed in further studies.
Abstract: To enable the investigation of fetal movement in a manner similar to fetal heart rate (FHR) monitoring we have developed an apparatus (the DopFet system) that consists of a pair of miniature sensors, a 2-MHz continuous-wave directional Doppler electronic module and a laptop personal computer. One of the sensors is aimed at the fetal limbs and the other at the thorax to detect heart and upper body movements. The signals are analyzed, presented in real-time and postprocessed by software developed by us. The postprocessing software computes a number of parameters (the DopFet parameters) describing fetal movement. These parameters can be divided into two categories: parameters that describe the quantity of fetal movement (i.e., number of movements) and parameters that describe qualitative aspects of fetal movement (i.e., average movement duration). Future studies using the DopFet system will be aimed at discovering which of these parameters or combination of parameters is the best indicator of fetal well-being. We present an example of a 0.5 h recording and the results of testing on 23 volunteer mothers. These results show good sensitivity of the system compared to real-time ultrasound (US). The system detects 96% of rolling movements, 100% of flexion movements and 97% of leg movements.
Abstract: The recent introduction of non-linear imaging in ultrasound diagnosis could improve image quality by resolving some problems in technically difficult patients allowing a better conspicuity in identification of subtle lesions. Tissue harmonics are generated while the transmitted pulse propagates through tissue. The formation of image by utilising the harmonic signals implies the suppression of fundamental frequency in the received signal. This is achieved by two major processes filtering and pulse inversion imaging. The non-linear properties of contrast agents reinforce the intensity of harmonic signals which could be detected in precise conditions of acoustic power for a non-destructive or destructive imaging. The introduction of this new imaging modality opens new way in ultrasound imaging with precise protocols of acquisition or sequences and possibly in therapy in the near future.
Abstract: The male partner is responsible for 50% of infertility in couples. Assessment of male infertility should include clinical examination, laboratory tests (semen analysis, dosage of gonadal and gonadotropic hormones) and sonographic examination of the urogenital tract. Male infertility is related to diverse abnormalities including testis lesions (infertility of secretory type) and obstructive disorders of the genital tract (infertility of excretory type). Sonographic examination with abdominal, scrotal and transrectal probes has become the major imaging modality to evaluate male infertility and especially to analyze infertility of excretory type related to inflammatory lesions, congenital agenesis of vas deferens and congenital cyst of the distal genital tract. The main purpose of this paper is to illustrate with sonography the normal anatomy of the male genital tract and to detail sonographic features of current pathologies responsible for human male infertility.
Abstract: PURPOSE: The objective of this study was to evaluate the ability of Doppler tissue imaging (DTI) to localize the ventricular emergence site of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome). METHODS: Thirty-three patients were studied prospectively by Doppler tissue imaging (128XP and Sequoia 256 echocardiographic systems; Acuson, Mountain View, Calif) before investigation of Wolff-Parkinson-White syndrome and after radiofrequency ablation of the accessory pathways. The normal appearance of the ventricular contractions was defined in a group of 10 control subjects. The preexcitation zone was determined as a zone of maximum acceleration in "DTI acceleration mode" or as a coded contraction zone in "DTI velocity mode," at the time of the delta wave or before the onset of the QRS complex. RESULTS: The earliest ventricular activation site was correctly localized for 12 of the 15 left-sided pathways (8 anterior or anterolateral, 2 lateral or posterolateral, 2 inferior). When wall motion abnormalities were detected in the left ventricle by DTI, the left-sided localization was confirmed by electrophysiologic exploration. For the right-sided pathways, the localization was correct in only 4 of 11 cases (3 posteroseptal and 1 anterolateral). After effective ablation in all patients, the abnormalities corresponding to the electrophysiologic data disappeared totally in only 11 of 16 patients. CONCLUSION: In the presence of Wolff-Parkinson-White syndrome, DTI localizes contraction abnormalities associated with early activation of a part of the ventricle. However, the interpretation of the images remains difficult because the normal coding of the contraction of the ventricular walls depends on the incidence for which they are investigated. This noninvasive examination seems to be an effective tool for localizing the left-sided accessory pathways of the left ventricle, in particular in the anterior, anterolateral, or inferior walls.
Abstract: Various parameters are currently used for the semi-quantitative assessment of dopamine D2 receptors and differ according to the delineation of the striatal region of interest (ROI) and the choice of the reference ROI. The aim of this study was to assess the value of different ROI approaches in differentiating patients with normal or increased numbers of D2 dopamine receptors (group 1 = Parkinson's disease, n = 8) from patients with decreased dopamine D2 receptors (group 2 = other extrapyramidal syndromes, n = 9) using 123I-iodolisuride SPET (ILIS-SPET). 123I-iodolisuride (190 +/- 31 MBq) and 99Tcm-ethyl cysteinate dimer (99Tcm-ECD) perfusion SPET were performed in the same position, with a dual-headed gamera camera equipped with fan beam collimators. Both a geometric approach (ellipse, circle or rectangle) and an anatomical approach using the CT scan and perfusion SPET as anatomical guides were used to draw striatal and reference ROIs. A total of 33 different parameters were calculated for each patient, indicating the ratio of counts between the striatal and reference ROIs (frontal, occipital cortex or cerebellum) and the asymmetry between the right and left striatum. More significant differences between group 1 and group 2 were found by using geometric ROIs than by using anatomical ROIs. The most discriminant ratios were the caudate/occipital, caudate/frontal and striatum/occipital ratios (P = 0.001, P = 0.002, P = 0.003 respectively). A close correlation was found between the striatum/caudate and striatum/occipital ratios, but not between the striatum/frontal and striatum/occipital ratios or between the striatum/frontal and striatum/caudate ratios. We conclude that the occipital cortex is the best reference for the semi-quantitative evaluation of dopamine D2 receptors as the frontal cortex could include some dopamine D2 receptor-bound radioligand, and that the caudate/occipital ratio is an appropriate parameter for differentiating Parkinson's disease from non-Parkinson extrapyramidal syndrome by 123I-iodolisuride SPET.
Abstract: The development of ultrasonography in vascular applications has entailed research of ultrasound parameters leading to precise the diagnosis and quantification of carotid lesions in routine. The use of recent colour Doppler imaging techniques (velocity or power encoding) is recommended as they allow a better definition of the lesions and recesses. At present, features of plaque that could be related to increased incidence of stroke are: echogenicity, with a more frequent observation of anechoic or hypoechoic lesions in the case of clinical signs; texture, with frequent haemorrhage; surface contour, with a high rate of ulcerations which were accompanied by stroke; plaque motion, with a significant alteration in plaque motility in symptomatic patients; progression or regression in size, with a faster progression of anechoic and hypoechoic plaques; an increase in plaque volume is associated with a greater risk of stroke; a significant relationship between the presence of "ulcers" and embolic activity. The quantification of stenosis degree could be made using velocity criteria and/or morphological criteria. Velocity criteria could be obtained at the site of the stenosis (direct criteria) or downstream the carotid stenosis using Duplex systems. Morphological criteria could be obtained using B-mode imaging or colour Doppler but this quantification remains difficult in case of diffuse carotid stenoses or very severe stenoses.
Abstract: PURPOSE: We assess long-term arterial pressure, renal function, and patient and graft survival in recipients of cadaveric kidney transplant with or without transplant renal artery stenosis. We also evaluate the risk factors for transplant renal artery stenosis. MATERIALS AND METHODS: We reviewed and analyzed baseline clinical, immunological and outcome data for 26 patients with transplant renal artery stenosis before and after angioplasty, and 72 without stenosis on angiography. We also analyzed graft and patient survival in 304 cases in which angiography was not performed. RESULTS: The incidence of transplant renal artery stenosis was 6.6% (26 of 402 patients). Acute rejection episodes (42 versus 22%, p <0.05) and delayed graft function (50 versus 32%, p <0.10) were more frequent, and mean cold ischemia time plus or minus standard error (29.2+/-1.7 versus 24.8+/-1.3 hours, p <0.01) was longer in patients with than without transplant renal artery stenosis. The technical success of angioplasty was 92.3%. Restenosis was documented in 6 of 26 patients (23.1%). Revascularization resulted in a decrease in arterial pressure and better renal function. The 8-year patient (100, 98.6 and 95.7%, respectively) and graft (88.1, 88.9 and 89.3%, respectively) actuarial survival rates were similar among patients with or without transplant renal artery stenosis, and those who did not undergo angiography. CONCLUSIONS: Transplant renal artery stenosis had no detectable influence on long-term arterial pressure control, renal function, and patient and graft survival rates, which were similar to those in patients without stenosis. Long cold ischemia time may have a role in the development of transplant renal artery stenosis through ischemia/reperfusion injury.
Abstract: The mechanisms leading to shunting through a patent foramen ovale include high right-sided cardiac pressures and respiratory factors due to mechanical ventilation and also anatomical changes in the right atrium as described in the platypnea-orthodeoxia syndrome. We report a patient with the adult respiratory distress syndrome (ARDS) who had a right-to-left atrial shunt which decreased in the prone position, after which oxygenation improved. The patient was admitted to the intensive care unit because of ARDS due to an invasive fungal infection. He had a history of chronic lymphocytic leukemia and paradoxical embolisms through a patent foramen ovale. Despite mechanical ventilation and antifungal treatment he developed severe ARDS. He was therefore turned to the prone position. Blood gas values improved dramatically (arterial oxygen tension/fractional inspired oxygen ratio increasing from 59 to 278 torr). Transcranial Doppler sonography was performed with bubble study, which confirmed a massive right-to-left shunt in the supine position and which instantaneously decreased in the prone position. This case suggests that a decrease in right-to-left shunt in patients who have a patent foramen ovale could partly explain the improvement in hypoxemia in the prone position.
Abstract: OBJECTIVE: This paper investigates the problems, advantages and potential applications of 20 MHz ultrasonic devices. METHOD: Aqueous gel and a thin appropriate membrane to enclose the front tip were used with 20 MHz probes without obvious decrease in resolution and sensitivity compared to the results obtained without a membrane and this considerably facilitates their routine use. RESULTS: Many applications with linear scanning were evaluated in dermatology, ophthalmology (investigations of the anterior chamber of the eye, checking of corneal grafts), stomatology (detection and evaluation of periodontal disease) and in the field of measurement of very low velocities in small vessels by means of a duplex probe comprising two 20 MHz transducers: an imaging transducer and an inclined blood flow measurement transducer. Velocity profiles (velocities less than 0.50 mm/s) were measured in 100-300 microm diameter vessels using a cross-correlation method. CONCLUSION: The use of 20 MHz frequency limits resolution but we have shown that this frequency allows the development of easy to handle probes.
Abstract: The objectives of this prospective study was to define the comparative ability of stress myocardial scintigraphy and dobutamine stress echocardiography to demonstrate post-MI myocardial viability, assessed on the functional recovery in terms of improvement of global and segmental kinetics by cardiac gamma-angiography after revascularization. 18 patients (11 anterior MI, 7 lateral or inferior MI) and 162 segments were analysed semiquantitatively. All patients with persistent significant stenosis underwent secondary revascularization of the artery responsible for myocardial infarction. The prevalence of viability was high, as only 34% of segments initially presented a segmental kinetic abnormality and contraction was improved at 6 months in 54% of cases. Stress scintigraphy and dobutamine echocardiography detected viability with a sensitivity of 96% and 70%, a specificity of 88% and 82%, a positive predictive value of 89% and 77% and a negative predictive value of 95% and 76%, respectively. Only the wall score index with low-dose dobutamine was correlated with the ejection fraction at 6 months. Stress echocardiography is a more reliable predictor of the degree of functional recovery after revascularization. Scintigraphy visualizes much more extensive abnormalities than echocardiography. This often corresponds to ischaemic territories with normal contraction under baseline conditions and low doses of dobutamine. It therefore seems preferable both examinations for optimal assessment of thrombolized patients following myocardial infarction.
Abstract: The recent introduction of tissue harmonic imaging could resolve the problems related to ultrasound in technically difficult patients by providing a marked improvement in image quality. Tissue harmonics are generated during the transmit phase of the pulse-echo cycle, that is, while the transmitted pulse propagates through tissue. Tissue harmonic images are formed by utilizing the harmonic signals that are generated by tissue and by filtering out the fundamental echo signals that are generated by the transmitted acoustic energy. To achieve this, two processes could be used; one by using filters for fundamental and harmonic imaging and the second using two simultaneous pulses with a 180 degrees difference in phase. The introduction of harmonics allows increased penetration without a loss of detail, by obtaining a clearer image at depth with significantly less compromise to the image quality caused by the use of lower frequencies. This imaging mode could be used in different organs with a heightening of low-contrast lesions through artefact reduction, as well as by the induced greater intrinsic contrast sensitivity of the harmonic imaging mode.
Abstract: The purpose of our study is to trace in vivo and during the perinatal period, the brain maturation process with exhaustive measures of the T2 relaxation time values. We also compared regional myelination progress with variations of the relaxation time values and of brain signal. T2 relaxation times were measured in 7 healthy premature newborns at the post-conceptional age of 37 weeks, using a Carr-Purcell-Meiboom-Gill sequence (echo time 60 to 150 ms), on a 2.35 Tesla Spectro-Imaging MR system. A total of 62 measures were defined for each subject within the brain stem, the basal ganglia and the hemispheric gray and white matter. The mean and standard deviation of the T2 values were calculated for each location. Regional T2 values changes and brain signal variations were studied. In comparison to the adult ones, the T2 relaxation time values of both gray and white matter were highly prolonged and a reversed ratio between gray and white matter was found. The maturational phenomena might be regionally correlated with a T2 value shortening. Significant T2 variations in the brainstem (p < 0.02), the mesencephalon (p < 0.05), the thalami (p < 0.01), the lentiform nuclei (p < 0.01) and the caudate nuclei (p < 0.02) were observed at an earlier time than they were visible on T2-weighted images. In the cerebral hemispheres, T2 values increased from the occipital white matter to parietal, temporal and frontal white matter (p < 0.05) and in the frontal and occipital areas from periventricular to subcortical white matter (p < 0.01). Maturational progress was earlier and better displayed with T2 measurements and T2 mapping. During the perinatal period, the measurements and analysis of T2 values revealed brain regional differences not discernible with T2-weighted images. It might be a more sensitive indicator for assessment of brain maturation.
Abstract: OBJECTIVE OF THE STUDY: To assess the usefulness of fetal karyotyping in the management of facial cleft lip with or without cleft palate diagnosed during pregnancy and to determine which etiologic and prognosis criteria are helpful to consider for prenatal counselling. MATERIAL AND METHODS: Retrospective study on 35 cases of facial cleft lip and/or palate prenatally diagnosed by ultrasound examination and managed in our fetal medicine unit from 1 January 1989 to 31 December 1996. Complete follow-up was obtained for all fetuses. RESULTS: In our series, the mean gestational age at diagnosis was 25 weeks. In 43% of the cases, additional sonographic anomalies were also recognized. These associated anomalies were more frequent when amniotic fluid quantity was abnormal. Fetal chromosomal determination was conducted in 2/3 of fetuses and numeric or structural abnormalities were found in 20% not related to the cleft size or type (lip and/or palate). All fetuses with isolated facial cleft were chromosomally normal. We report 4 midline clefts, all of them were associated with additional sonographic findings and 3 were part of an holoprosencephaly. CONCLUSION: Prenatal diagnosis of cleft lip and/or palate must draw attention to associated sonographic anomalies especially when amniotic fluid quantity is abnormal. Chromosomal karyotyping is not necessary when facial clefting is isolated except in cases diagnosed early in pregnancy. Midline clefts must draw attention on cerebral midline integrity.
Abstract: PURPOSE: We assessed the usefulness of color Doppler imaging and spectral analysis in monitoring the effect of isovolemic hemodilution on retinal vein occlusion. METHODS: Color Doppler imaging was used to measure the systolic and diastolic blood flow velocities and the resistance index (RI) in the central retinal artery and the maximum and minimum blood flow velocities in the central retinal vein of affected eyes and contralateral unaffected eyes before and 1 day after isovolemic hemodilution in 70 adults (40 men and 30 women; mean age, 62.4 +/- 13.7 years) who presented with retinal vein occlusion. RESULTS: With hemodilution, the hematocrit value was decreased from 41.8 +/- 3.0 to 33.0 +/- 3.0. In central retinal vein occlusion, the pretreatment arterial and venous flow velocities of affected eyes were significantly lower than those of unaffected eyes. After hemodilution in eyes affected by ischemic occlusion, a significant improvement in the RI in the central retinal artery was observed without changes in venous flow velocity. After hemodilution in eyes affected by non-ischemic occlusion, a significant increase in maximal venous flow velocity only was noted. In branch retinal vein occlusion, no significant difference was observed in the RI between affected and unaffected eyes. After hemodilution, an improvement in RI was noted only for affected eyes. CONCLUSIONS: The present results confirm the potential value of Doppler analysis in monitoring the impact of hemodilution on arterial and venous velocity in patients with central retinal vein occlusion.
Abstract: We assessed the long-term (M +/- SE: 68 +/- 3 months) arterial pressure and renal function of cadaveric kidney transplant recipients with and without significant (> 70% diameter reduction) transplant renal artery stenosis (TRAS) at angiography. Baseline clinical, immunological and outcome data for 26 patients with TRAS (incidence of TRAS: 6.6%) before and following angioplasty and 72 patients without stenosis at angiography were reviewed and analyzed. The 2 groups were similar with respect to recipient sex ratio and age (45 vs 46), duration of transplantation (7 months), cause of renal failure, donor sex and age, HLA-antigen mismatches and titers of anti-HLA antibodies, CMV infection and anti-CMV antibodies in donors and recipients. The technical success of angioplasty was 92.3%. Restenosis was documented in 6/26 patients (23.1%). Revascularization resulted in a decrease of arterial pressure and number of antihypertensive medications and a lower serum creatinine compared to baseline values. The long-term arterial pressure and serum creatinine levels were similar in patients with and without stenosis. In conclusion, TRAS after revascularization had no detectable influence on the long-term arterial pressure control and renal function within a follow-up period of 68 +/- 3 months.
Abstract: Akinetic mutism is a reactive status with permanent opening of the eyes. The accountable lesions are always bilateral. The injured cerebral structures include the frontal gyri, the thalami or the mesencephalic areas. In one case of a 44-year-old patient, magnetic resonance imaging and computed tomography were not contributive. Tc99m brain SPECT imaging was performed and displayed bilateral frontal hypoactivity. This case suggests that this technique could be helpful for diagnosis when clinical features and radiological pattern are opposite.
Abstract: PURPOSE: In patients with aerodigestive cancer, laryngectomy places the esophagus in a superficial position, allowing easy ultrasound examination of this organ. The purpose of the present study was to assess oesophagus morphology after laryngectomy using echotomography and to compare this morphology with voice quality. MATERIAL AND METHODS: In the present study, ultrasonography was performed in 28 patients (delay from surgery: 3 +/- 3 years): 15 were operated using laryngectomy technique (LT) and 13 with pharyngolaryngectomy technique (PLT). On transversal echography, antero-posterior and latero-lateral diameters, esophagus area and dilatation during phonation were systematically measured. These data were compared to the voice quality assessed by two independent observers. RESULTS: A smaller latero-lateral diameter and area were found in the PLT group than in the LT group (p < 0.05) with a flat aspect in group LT. This was associated with faster and better voice acquisition in the PLT group. CONCLUSION: Morphologic study of the esophagus after laryngectomy using ultrasound is in favor of pharyngolaryngectomy technique which allows better conditions for acquiring esophageal voice in better conditions. This could be due to the small area, circle shape and tonicity of the esophagus after this type of surgery.
Abstract: After 6 years of experience, Spencer and colleagues described the detection of embolus signals as height intensity transient signals (HITS) within Doppler flow spectrum from intracranial vessels. These signals (gaseous or materials) are recorded in many situations such as cardiac prosthetic valves, atrial fibrillation, carotid stenosis, carotid surgery or angioplasty. The clinical value is not well known: neurological impairment associated with brain lesions is described in case of cardiac prosthetic valves. The observation of HITS in carotid stenosis is associated with an increased risk of stroke. The detection of HITS offers a new orientation in studying stroke but some technical and/or clinical difficulties have to be solved.
Abstract: The basic physiological variable in hypoxic-ischaemic brain injury is cerebral oxygen delivery. When oxygen delivery becomes insufficient to meet the cellular demands for oxygen, a sequence of biochemical events will be triggered leading to cell death. High levels of CBF following severe birth asphyxia is now well documented by Doppler ultrasound which has been shown to be a useful prognostic indicator following birth asphyxia. Near infrared spectroscopy (NIRS) is of great potential value since it may be used at the bed-sid and allows to measure the cerebral blood volume and the concentrations of cytochrome aa3. Magnetic resonance spectroscopy (MRS) allows noninvasive assessment of cerebral metabolism in asphyxiated neonates. 31P MRS has demonstrated that birth asphyxia leads to delayed impairment of cerebral energy metabolism and is predictive of later neurodevelopmental outcome. 1H MRS has shown lactate accumulation and a later decline in N-acetyl aspartate concentration.
Abstract: Local lesions occurring after conservative surgery for breast neoplasms require diagnostic means capable of detecting and assessing the recurrence of such cancers. In the present color-coded Doppler was used in 20 women who had under gone conservative surgery (mean 4 years before) to screen all suspect lesions. Among the 14 malignant lesions assessed histologically, one or more arterial vessels were detected inside or beside the lesion in 13. Among the 6 benign lesions, only of one arterial vessel was detected, in all cases far from the lesion (12.5 to 3.3 mm). No significant difference was observed for systolic velocities and resistance index. These results indicate high accuracy of color coded Doppler examination associated with echotomography and mammography for positive diagnosis of recurrent lesions in post-conservative follow-up of breast cancer.
Abstract: Cerebral metabolism has been extensively studied by magnetic resonance spectroscopy (MRS). MRS allows the study of neonates brain maturation as well as the onset and the evolution of brain injury. The use of phosphorous spectroscopy allows the quantification of phosphorylated metabolites. Thus, the measurement of the relative concentrations of creatine-phosphate and inorganic-phosphate is a prognostic factor of the outcome of a neonate after birth asphyxia. Absolute concentrations have more recently been studied and seem to be more significant. Proton MRS gives access to brain metabolites such as choline, lactate, N-acetyl aspartate and taurine. Its use is more recent than the phosphorous spectroscopy but first results already show its potential in neonatology.
Abstract: In the present case Color Coded Doppler showed a marked increase in vascularization in the right lobe of the thyroid with high systolic velocities (1 m/s). This sign was only doubtful compared with clinical, biological and isotopic data. Because of dramatic laryngeal dyspnea, surgery was conducted which allowed the final diagnosis of thyroid invasion by tracheal epidermoid carcinoma. This demonstrates the particular role of Color Coded Doppler in the management of inflammatory thyroid diseases.
Abstract: Progressive supranuclear palsy (PSP) may sometimes be misdiagnosed as Parkinson's disease in its early stages, hence an early positive diagnosis of PSP based on dopamine D2 receptor density could be extremely valuable. In the present case report, the absence of dopamine D2 receptors was clearly demonstrated in the striatum using 123I-iodobenzamide (IBZM) tomoscintigraphy. This illustrates the potential use of IBZM tomoscintigraphy to identify Parkinson-like's disease presenting with decreased dopamine D2 receptor density; and hence to predict L-Dopa effectiveness. Further studies are needed to evaluate the vaue of IBZM tomoscintigraphy in the different Parkinson's like diseases.
Abstract: The relationship between intracranial pressure or cerebral perfusion pressure (CPP), cerebral blood flow, and brain energy failure is unpredictable throughout the development of acute intracranial hypertension. The purpose of the present study was to correlate intracranial pressure with cerebral blood flow velocities and brain energy metabolism in adult rabbits. The acute intracranial hypertension was achieved by pressure transmission. Transcranial Doppler wave-forms were obtained from the basilar artery for monitoring cerebral blood flow velocities. 31P-Magnetic resonance spectroscopy was used to assess brain energy metabolism. The diastolic blood flow velocity began to decrease significantly (34.5%) when the intracranial pressure was equal to half the diastolic arterial pressure for a CPP of 36 +/- 18 mmHg. Circulatory cerebral resistances increased significantly (55%) for the same value of CPP. Diastolic frequency was near zero when intracranial pressure approached diastolic arterial pressure (51 +/- 12 mmHg), corresponding to a CPP of 30 +/- 15 mmHg. At the same time, only a tendency for brain energy metabolism to decrease was observed. Consequently, transcranial Doppler sonography could be proposed for the follow-up of intracranial hypertension. Magnetic resonance spectroscopy could help to monitor these patients and could be especially proposed in case of high intracranial pressure (near diastolic arterial pressure). The joint use of these two methods would help in making appropriate therapeutic decision in humans.
Abstract: This experiment is the first to compare cerebral vasomotor reactivity in the supra- and infra-tentorial regions in baseline conditions and during progressive acute intracranial hypertension. The increase in intracranial pressure was performed using liquid pressure transmission in two groups of 16 rabbits by elevating a saline infusion bottle connected to the subdural space. Cerebral microvessel dilation capacity was studied using acetazolamide arterial infusion during three stages of 20 min: at baseline conditions, with an intracranial pressure value equal to half the diastolic arterial pressure and with an intracranial pressure equal to the diastolic arterial pressure. The effects of acetazolamide in the basilar artery and in the carotid siphon were simultaneously monitored by transcranial Doppler sonography during all the experiments. The changes in cerebral vasomotor reactivity occurred with the same intensity and latency in both vascular compartments in baseline conditions. The maximum amplitude of changes happened 30 s later in the basilar artery than in the carotid siphon. When intracranial pressure was above half the diastolic arterial pressure, the vasomotor tone began to decrease in the carotid siphon which supplies a small region of the rabbit brain, whereas it was maintained in the basilar artery. This effect could be explained by brain tissue hypertension. Vasomotor reactivity had nearly disappeared in all the cerebral arteries investigated when intracranial hypertension was equal to the diastolic arterial pressure. These results show evidence of a direct and late effect of acute elevation of intracranial pressure on cerebral microvascular tone. This begins in the supra-tentorial region but there is an early local effect on the carotid siphon due to the brain tissue pressure.
Abstract: Regional hypoperfusion is a very frequent complication of subarachnoid haemorrhage (SAH), being related to vasospasm in the majority of cases. Twenty-six patients who were admitted for SAH underwent follow-up with technetium-99m hexamethylpropylene amine oxime single photon emission tomography (SPECT) 3 and 8 days after surgery. Fifteen patients of these had one more examination 15 days after surgery. The degree of hypoperfusion was quantified using an index of asymmetry which allow the comparison of two symmetrical regions of interest (ROIs) on the transaxial slice which presented the greatest perfusion defect. Comparison of CT data, transcranial Doppler data and clinical signs with the perfusion as quantified by 99mTc-HMPAO SPECT indicates that a difference in counts of less than 10% between the two symmetrical ROIs is of no diagnostic value. Follow-up of the brain perfusion clearly shows that the most pronounced hypoperfusion was observed just after surgery, with progressive normalization at 8 and 15 days after surgery. 99mTc-HMPAO SPECT performed 8 days after surgery allows prediction of the clinical outcome. For these reasons, 99mTc-HMPAO SPECT, which is the only method for follow-up of cerebral perfusion in routine clinical practice, should be the first examination to be performed after surgery in patients with SAH.
Abstract: For many years Doppler ultrasound has helped to identify the cause of renal allograft dysfunction. However, Doppler examinations were often performed after the onset of acute renal failure. In the present study we used Doppler ultrasound during grafting to follow changes in renovascular resistance. As early as 30 min after the renal artery had been unclamped, the calculated resistance index (RI) at the hilar part of the renal artery was significantly higher in the group of patients who developed acute tubular necrosis (ATN) than in the group of patients with early normalization of renal function (P = 0.05). This result did not correlate with raised cold and warm ischemia times and serum creatinine level on discharge in patients who presented with ATN. RI higher than 0.730 min after unclamping allows for an identification of those grafts at greater risk for the development of ATN and should be an indication for the early introduction of intensive therapy.
Abstract: Pulsed Doppler ultrasound was used to investigate fetal and maternal ovine circulation in 16 ewes. Resistance index (R) was measured at the following sites: umbilical, fetal cerebral, and uterine arteries. Measurements were performed at days 80, 100, and 130 of gestation, day 0 being the day of mating. Normal ranges of the Doppler indices were delimited on the six control ewes. Five ewes were treated by intramuscular injection of 10 mg of nicotine 5 days per week and five others received placebo injections. No difference was found on the Doppler indices between the control group and the placebo group. The cerebral indices did not differ in the three groups at days 80 and 100 but were significantly higher at day 130 in the nicotine group in comparison to the two others (p less than 0.01). The umbilical indices were slightly elevated at days 80 and 130 in the nicotine group. No significant difference was found on the uterine indices at any of the three stages of gestation whatever the treatment. In the control and placebo groups the ewes delivered in the normal ranges of gestation length. In these groups 2 of 20 lambs (10%) died at birth. In the nicotine group 2 ewes delivered prematurely and 8 of the 13 lambs (62%) were stillborn. In conclusion, repeated nicotine injections induce vasoconstriction on the umbilical and cerebral arteries of the fetus at the end of the gestation and are associated with poor perinatal outcome.
Abstract: A transcranial Doppler sonographic system with a special 2-MHz probe for prolonged experimentation has been developed for Doppler waveform recordings from the basilar artery on rabbits. Measurements were made from the maximum velocity wave form, and Pourcelot's resistance index was used to express the results. The diastolic flow, similar to that observed in humans in physiological conditions, decreases with increased intracranial pressure during chronic intracranial hypertension. This Doppler model may be valuable for assessing rapid changes of cerebral blood flow in conscious animals during prolonged or acute experimental procedures.
Abstract: Ultrasound techniques and radionuclide studies are very often used to assess vascularization of renal transplants. Although, in acute tubular necrosis or acute rejection, it is difficult to choose between these two techniques, in 3 recent cases of renal artery thrombosis, we conclude that color coded Doppler is preferable to nuclear medicine or duplex system to diagnose this form of thrombosis.
Abstract: Fetal cerebral arteries have been explored during normal pregnancies (n = 40). The index of cerebral resistance (Rc) as defined by Pourcelot (Rc = (S-D)/S where S is the systolic amplitude and D is the diastolic amplitude) shows variations similar to the placental index (Rp). During normal pregnancy, the cerebral index is higher than the placental index and the cerebro-placental ratio (Rc/Rp) is greater than one. This preliminary study of the umbilical and cerebral circulation during 21 pathological pregnancies with hypertension seems to demonstrate that when fetal growth retardation is also present (n = 6) either or both of the indices Rc and Rp may be outside the normal range but the cerebro-placental ratio (CPR) is always less than one. However, a larger number of patients needs to be explored in order to evaluate the clinical usefulness of such an observation.
Abstract: We report here the visualization of the intra-cerebral vessels in a normal fetus of 28 weeks gestational age, by color-coded Doppler. The color-flow mapping method makes it possible to identify very small vessels that up to date could not be detected on B-mode imaging, and will permit new clinical and physiological studies of the circulation in specific areas of the fetal brain.
Abstract: During normal pregnancies (n = 40) the cerebral index (Rc = S - D/S) (with S = systolic and D-telediastolic amplitudes) is always higher than the placental index (Rp), and the cerebro/placental ratio (Rc/Rp) greater than 1. Of 29 pregnant women with hypertension (including two twins), 17 delivered normally (Rc, Rp and CPR normal), 14 delivered an hypotrophic fetus, in 12 out of these 14 pregnancies one of the two indices (Rc or Rp) was abnormal and the cerebro/placental ratio, CPR, was always less or equal to 1. CPR sensitivity was 86% the specificity 100%. In 11 pregnancies with idiopathic fetal-growth retardation, the CPR was less or equal to 1 in eight cases (73% of the cases), and greater than 1 in three cases (three false-negative results).
Abstract: Umbilical circulation can be explored by Doppler ultrasound methods very easily. The umbilical arteries spectrum provides information on the placental circulation. The diastolic flow is directly related to the vascular resistances of the placenta (Rp). In cases of pathological pregnancies with hypertension the decrease in the diastolic flow and the increase in the resistance index Rp have been correlated with intra-uterine fetal growth retardation. The specificity of this index Rp is of 95% but the sensitivity much more lower (approximately 70%). For that reason Doppler assessment of the fetal circulation in other areas has been recently carried out. Fetal cerebral arteries have been explored during normal pregnancies. The index of cerebral resistances as defined by Pourcelot Rc = S-D divided by S (with S systolic amplitude and D diastolic amplitude) show similar variations to the placental index but later in the pregnancy. During the pregnancy the cerebral index is higher than the placental one and the cerebro placental ratio (CPR) superior to 1. During pathological pregnancy (hypertension) with fetal growth retardation one of the index Rc or Rp may be out of the normal range but the cerebro placental ratio CPR is always lower than 1. The follow up of both the umbilical and cerebral circulation increases notably the accuracy of the Doppler method for the detection of intra-uterine fetal growth retardation.
