Abstract: PURPOSE: The purpose was to retrospectively review the data of 27 patients with renal insufficiency who underwent conventional angiography with gadolinium-based contrast agents (GDBCA) as alternative contrast agents and assess the occurrence of nephrogenic systemic fibrosis (NSF) together with associated potential risk factors. METHODS: This HIPAA-compliant study had institutional review board approval, and informed consent was waived. Statistical analysis was performed for all available laboratory and clinical data, including dermatology reports. Type and amount of the GDBCA used were recorded for angiography and additional MRI studies, if applicable. Serum creatinine levels (SCr) pre- and post-angiography were recorded, and estimated glomerular filtration rates (eGFR) were calculated. RESULTS: Ten female and 17 male patients who underwent angiography with GDBCA were included. The mean amount of GDBCA administered was 44 +/- 15.5 ml (range 15-60 ml) or 0.24 + 0.12 mmol/kg (range 0.1-0.53 mmol/kg). At the time of angiography all patients had renal insufficiency (eGFR <60 ml/min/1.73 m(2)). Mean eGFR pre-angiography was 26 ml/min/1.73 m(2) and 33 ml/min/1.73 m(2) post-angiography. The mean follow-up period covers 28 months, range 1-84 months. Additional MRI studies with GDBCA administration were performed in 15 patients. One patient with typical skin lesions had developed biopsy-confirmed NSF. CONCLUSION: Conventional arterial angiography with GDBCA may play a role in the development of NSF in patients with renal insufficiency. Alternative contrast agents, such as CO(2) angiography or rather the use of low doses of iodinated contrast agents, should be considered in these patients.
Abstract: On May 3, 2008, a National Cancer Institute (NCI)-sponsored open consensus conference was held in Toronto, Ontario, Canada, during the 2008 International Society for Magnetic Resonance in Medicine Meeting. Approximately 100 experts and stakeholders summarized the current understanding of diffusion-weighted magnetic resonance imaging (DW-MRI) and reached consensus on the use of DW-MRI as a cancer imaging biomarker. DW-MRI should be tested as an imaging biomarker in the context of well-defined clinical trials, by adding DW-MRI to existing NCI-sponsored trials, particularly those with tissue sampling or survival indicators. Where possible, DW-MRI measurements should be compared with histologic indices including cellularity and tissue response. There is a need for tissue equivalent diffusivity phantoms; meanwhile, simple fluid-filled phantoms should be used. Monoexponential assessments of apparent diffusion coefficient values should use two b values (>100 and between 500 and 1000 mm2/sec depending on the application). Free breathing with multiple acquisitions is superior to complex gating techniques. Baseline patient reproducibility studies should be part of study designs. Both region of interest and histogram analysis of apparent diffusion coefficient measurements should be obtained. Standards for measurement, analysis, and display are needed. Annotated data from validation studies (along with outcome measures) should be made publicly available. Magnetic resonance imaging vendors should be engaged in this process. The NCI should establish a task force of experts (physicists, radiologists, and oncologists) to plan, organize technical aspects, and conduct pilot trials. The American College of Radiology Imaging Network infrastructure may be suitable for these purposes. There is an extraordinary opportunity for DW-MRI to evolve into a clinically valuable imaging tool, potentially important for drug development.
Abstract: BACKGROUND: Lymph node staging of bladder or prostate cancer using conventional imaging is limited. Newer approaches such as ultrasmall superparamagnetic particles of iron oxide (USPIO) and diffusion-weighted magnetic resonance imaging (DW-MRI) have inconsistent diagnostic accuracy and are difficult to interpret. OBJECTIVE: To assess whether combined USPIO and DW-MRI (USPIO-DW-MRI) improves staging of normal-sized lymph nodes in bladder and/or prostate cancer patients. DESIGN, SETTING, AND PARTICIPANTS: Twenty-one consecutive patients with bladder and/or prostate cancer were enrolled between May and October 2008. One patient was excluded secondary to bone metastases detected on DW-MRI with subsequent abstention from surgery. INTERVENTION: Patients preoperatively underwent 3-T MRI before and after administration of lymphotropic USPIO using conventional MRI sequences combined with DW-MRI. Surgery consisted of extended pelvic lymphadenectomy and resection of primary tumors. MEASUREMENTS: Diagnostic accuracies of the new combined USPIO-DW-MRI approach compared with the "classic" reading method evaluating USPIO images without and with DW-MRI versus histopathology were evaluated. Duration of the two reading methods was noted for each patient. RESULTS AND LIMITATIONS: Diagnostic accuracy (90% per patient or per pelvic side) was comparable for the classic and the USPIO-DW-MRI reading method, while time of analysis with 80 min (range 45-180 min) for the classic and 13 min (range 5-90 min) for the USPIO-DW-MRI method was significantly shorter (p<0.0001). Interobserver agreement (three blinded readers) was high with a kappa value of 0.75 and 0.84, respectively. Histopathological analysis showed metastases in 26 of 802 analyzed lymph nodes (3.2%). Of these, 24 nodes (92%) were correctly diagnosed as positive on USPIO-DW-MRI. In two patients, one micrometastasis each (1.0x0.2 mm; 0.7x0.4 mm) was missed in all imaging studies. CONCLUSIONS: USPIO-DW-MRI is a fast and accurate method for detecting pelvic lymph node metastases, even in normal-sized nodes of bladder or prostate cancer patients.
Abstract: OBJECTIVE: In this experimental study we assessed the diagnostic performance of digital linear slit scanning radiography compared with computed radiography (CR) for the detection of urinary calculi in an anthropomorphic phantom imitating patients weighing approximately 58-88 kg. CONCLUSION: Compared with CR, linear slit scanning radiography is superior for the detection of urinary stones and may be used for pretreatment localization and follow-up at a lower patient exposure.
Abstract: PURPOSE: To prospectively assess the potential of noninvasive diffusion-weighted magnetic resonance (MR) imaging to depict changes in microperfusion and diffusion in patients with acute unilateral ureteral obstruction. MATERIALS AND METHODS: The local ethics committee approved the study protocol. Informed consent was obtained. Diffusion-weighted MR imaging was performed in 21 patients (two women, 19 men; mean age, 43 years +/- 10 [standard deviation]) with acute unilateral ureteral obstruction due to a calculus diagnosed at unenhanced computed tomography. A control group (one woman, 15 men; mean age, 44 years +/- 12) underwent the same MR protocol. Standard processing yielded an apparent diffusion coefficient (ADC) ADCT; the separation of microperfusion and diffusion contributions yielded the perfusion fraction FP and the pure diffusion coefficient ADCD. ADCT, ADCD, and FP were compared between obstructed and contralateral unobstructed kidneys and with control values. For statistical analysis, nonparametric rank tests were used. A P value of less than .05 was considered significant. RESULTS: No significant differences were observed between the ADCT of the medulla or cortex of the obstructed and unobstructed kidneys. Compared with control kidneys, only medullary ADCT was slightly increased in the obstructed kidney (P < .04). However, the ADCD in the medulla of the obstructed and unobstructed kidneys was significantly higher than that in control subjects (201 x 10(-5) mm2/sec +/- 16 and 199 x 10(-5) mm2/sec +/- 20 vs 189 x 10(-5) mm2/sec +/- 12; P < .008 and P < .03, respectively). FP of the cortex of the obstructed kidney was significantly lower than that in the unobstructed kidney (20.2% +/- 4.8 vs 24.0% +/- 5.8; P < .002); FP of the medulla was slightly lower in the obstructed kidney than in the unobstructed kidney (18.3% +/- 5.9 vs 20.7% +/- 6.4; P = .05). CONCLUSION: Diffusion-weighted MR imaging allows noninvasive detection of changes in renal perfusion and diffusion during acute unilateral ureteral obstruction, as exemplified in patients with a ureteral calculus.
Abstract: PURPOSE: To evaluate the function of the parotid glands before and during gustatory stimulation, using an intrinsic susceptibility-weighted MRI method (blood oxygenation level dependent, BOLD-MRI) at 1.5T and 3T. MATERIALS AND METHODS: A total of 10 and 13 volunteers were investigated at 1.5T and 3T, respectively. Measurements were performed before and during gustatory stimulation using ascorbate. Circular regions of interest (ROIs) were delineated in the left and right parotid glands, and in the masseter muscle for comparison. The effects of stimulation were evaluated by calculating the difference between the relaxation rates, DeltaR(2)*. Baseline and stimulation were statistically compared (Student's t-tests), merging both parotid glands. RESULTS: The averaged DeltaR(2)* values prestimulation obtained in all parotid glands were stable (-0.61 to 0.38 x 10(-3) seconds(-1)). At 3T, these values were characterized by an initial drop (to -2.7 x 10(-3) seconds(-1)) followed by a progressive increase toward the baseline. No significant difference was observed between baseline and parotid gland stimulation at 1.5T, neither for the masseter muscle at both field strengths. A considerable interindividual variability (over 76%) was noticed at both magnetic fields. CONCLUSION: BOLD-MRI at 3T was able to detect DeltaR(2)* changes in the parotid glands during gustatory stimulation, consistent with an increase in oxygen consumption during saliva production.
Abstract: PURPOSE: To prospectively determine if changes in intrarenal oxygenation during acute unilateral ureteral obstruction can be depicted with blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging. MATERIALS AND METHODS: The study was approved by the local ethics committee, and written informed consent was obtained from all patients. BOLD MR imaging was performed in 10 male patients (mean age, 45 years +/- 17 [standard deviation]; range, 20-73 years) with a distal unilateral ureteral calculus and in 10 healthy age-matched male volunteers to estimate R2*, which is inversely related to tissue Po(2). R2* values were determined in the cortex and medulla of the obstructed and the contralateral nonobstructed kidneys. To reduce external effects on R2*, the R2* ratio between the medulla and cortex was also analyzed. Statistical analysis was performed with nonparametric rank tests. P < .05 was considered to indicate a significant difference. RESULTS: All patients had significantly lower medullary and cortical R2* values in the obstructed kidney (median R2* in medulla, 10.9 sec(-1) [range, 9.1-14.3 sec(-1)]; median R2* in cortex, 10.4 sec(-1) [range, 9.7-11.3 sec(-1)]) than in the nonobstructed kidney (median R2* in medulla, 17.2 sec(-1) [range, 14.6-23.2 sec(-1)], P = .005; median R2* in cortex, 11.7 sec(-1) [range, 11.0-14.0 sec(-1)], P = .005); values in the obstructed kidneys were also significantly lower than values in the kidneys of healthy control subjects (median R2* in medulla, 16.1 sec(-1) [range, 13.9-18.1 sec(-1)], P < .001; median R2* in cortex, 11.6 sec(-1) [range, 10.5-12.9 sec(-1)], P < .001). R2* ratios in the obstructed kidneys (median, 1.06; range, 0.85-1.27) were significantly lower than those in the nonobstructed kidneys (median, 1.49; range, 1.26-1.71; P = .005) and those in the kidneys of healthy control subjects (median, 1.38; range, 1.23-1.47; P < .001). In contrast, R2* ratios in the nonobstructed kidneys of patients were significantly higher than those in kidneys of healthy control subjects (P = .01). CONCLUSION: Increased oxygen content in the renal cortex and medulla occurs with acute unilateral ureteral obstruction, suggesting reduced function of the affected kidney.
Abstract: PURPOSE OF REVIEW: During recent years, (chemo)radiotherapy has evolved into a primary treatment modality for both early and advanced laryngeal and hypopharyngeal carcinomas. Head and neck surgeons will be concerned more frequently with patients presenting symptoms and signs suggesting recurrent tumor or complications of (chemo)radiotherapy. RECENT FINDINGS: Analysis of histologic characteristics and tumor spread of recurrent carcinomas on whole-organ slices of salvage laryngectomy specimens showed that recurrent laryngeal carcinomas are often present with multiple tumor foci dispersed in different regions; furthermore, they may develop beneath an intact mucosa. Only a few articles analyze the reliability of laryngoscopy and biopsy in detecting recurrences after (chemo)radiotherapy: the number of false negative biopsies is relatively high. The differentiation between radionecrosis and tumor recurrence is difficult by computed tomography scan and magnetic resonance imaging in many cases. Positron emission tomography-computed tomography and diffusion-weighted magnetic resonance imaging are promising diagnostic modalities to detect or exclude persistent or recurrent disease after (chemo)radiotherapy. SUMMARY: Endoscopy with biopsy, computed tomography scan and conventional magnetic resonance imaging present several deficiencies in diagnosing recurrent disease after (chemo)radiotherapy. New imaging modalities such as positron emission tomography-computed tomography and diffusion-weighted magnetic resonance imaging show promising results, increasing the diagnostic efficacy.
Abstract: Diffusion-weighted MRI has become more and more popular in the last couple of years. It is already an accepted diagnostic tool for patients with acute stroke, but is more difficult to use for extracranial applications due to technical challenges mostly related to motion sensitivity and susceptibility variations (e.g., respiration and air-tissue boundaries). However, thanks to the newer technical developments, applications of body DW-MRI are starting to emerge. In this review, we aim to provide an overview of the current status of the published data on DW-MRI in extracranial applications. A short introduction to the physical background of this promising technique is provided, followed by the current status, subdivided into three main topics, the functional evaluation, tissue characterization and therapy monitoring.
Abstract: OBJECTIVE: To assess the accuracy of preoperative imaging studies and clinical and endoscopic examinations for recurrent laryngeal carcinoma evaluation. STUDY DESIGN AND SETTING: A retrospective comparative study was performed at a university department on 42 recurrent laryngeal carcinomas. Surgical specimens were cut into whole-organ slices. Histologic findings were compared with the findings of the different preoperative diagnostic modalities. RESULTS: The craniocaudal tumor spread was correctly evaluated by endoscopy and imaging studies in 52% and 24%, respectively, and the contralateral tumor spread in 50% and 52%, respectively. The sensitivity, specificity, and accuracy for detection of tumor infiltration of the thyroid was 48%, 88%, and 64% and of the cricoid 47%, 80%, and 67%. The accuracy of recurrent tumor classification (crT) was 50%; most tumors were underclassified. CONCLUSION: The inadequately evaluated tumor spread and the inadequately classified recurrent tumors were underestimated and underclassified in most cases, respectively.
Abstract: Imaging of salivary gland tumours is a major challenge for radiologists due to the great variety of differential diagnoses. This article gives a short overview on the anatomy of the salivary glands, the epidemiology of salivary gland tumours as well as the clinical presentation and the different imaging modalities including new magnetic resonance techniques such as diffusion-weighted magnetic resonance imaging, dynamic contrast-enhanced magnetic resonance imaging and magnetic resonance spectroscopy applied in the work-up of salivary gland masses. The imaging features of different tumour types and their differential diagnoses are also discussed. Finally, staging classification and treatment options are presented.
Abstract: PURPOSE: To prospectively evaluate feasibility and reproducibility of diffusion-weighted (DW) and blood oxygenation level-dependent (BOLD) magnetic resonance (MR) imaging in patients with renal allografts, as compared with these features in healthy volunteers with native kidneys. MATERIALS AND METHODS: The local ethics committee approved the study protocol; patients provided written informed consent. Fifteen patients with a renal allograft and in stable condition (nine men, six women; age range, 20-67 years) and 15 age- and sex-matched healthy volunteers underwent DW and BOLD MR imaging. Seven patients with renal allografts were examined twice to assess reproducibility of results. DW MR imaging yielded a total apparent diffusion coefficient including diffusion and microperfusion (ADC(tot)), as well as an ADC reflecting predominantly pure diffusion (ADC(D)) and the perfusion fraction. R2* of BOLD MR imaging enabled the estimation of renal oxygenation. Statistical analysis was performed, and analysis of variance was used for repeated measurements. Coefficients of variation between and within subjects were calculated to assess reproducibility. RESULTS: In patients, ADC(tot), ADC(D), and perfusion fraction were similar in the cortex and medulla. In volunteers, values in the medulla were similar to those in the cortex and medulla of patients; however, values in the cortex were higher than those in the medulla (P < .05). Medullary R2* was higher than cortical R2* in patients (12.9 sec(-1) +/- 2.1 [standard deviation] vs 11.0 sec(-1) +/- 0.6, P < .007) and volunteers (15.3 sec(-1) +/- 1.1 vs 11.5 sec(-1) +/- 0.5, P < .0001). However, medullary R2* was lower in patients than in volunteers (P < .004). Increased medullary R2* was paralleled by decreased diffusion in patients with allografts. A low coefficient of variation in the cortex and medulla within subjects was obtained for ADC(tot), ADC(D), and R2* (<5.2%), while coefficient of variation within subjects was higher for perfusion fraction (medulla, 15.1%; cortex, 8.6%). Diffusion and perfusion indexes correlated significantly with serum creatinine concentrations. CONCLUSION: DW and BOLD MR imaging are feasible and reproducible in patients with renal allografts.
Abstract: PURPOSE: We evaluated the incidence and clinical relevance of alternate or additional findings on unenhanced CT in patients with acute flank pain and suspected urinary calculi. MATERIALS AND METHODS: A consecutive series of 1,500 patients underwent unenhanced CT due to acute flank pain. The absence or presence of urinary tract calculi and their localization were recorded. Alternate or additional CT findings were classified according to whether they required immediate or deferred treatment, or were of little or no clinical importance. RESULTS: Of the 1,500 patients 1,035 (69%) had urinary tract calculi, including 309 (30%) with nephrolithiasis, 377 (36%) with ureterolithiasis and 349 (34%) with the 2 conditions. Urolithiasis alone was found in 331 of these patients (32%) and additional pathological conditions were noted in 704 (68%). Of all patients 1,064 (71%) had other or additional CT findings. Of all patients 207 (14%) had nonstone related CT findings requiring immediate or deferred treatment, 464 (31%) had pathological conditions of little clinical importance and 393 (26%) had pathological conditions of no clinical relevance. CT was normal in 105 of all patients (7%). CONCLUSIONS: Unenhanced CT in patients with acute flank pain allows the accurate diagnosis of urinary stone disease and it can also provide further important information leading to emergency or deferred treatment in a substantial number of patients.
Abstract: OBJECTIVE: To analyze the incidence and diagnostic difficulties of radionecrosis vs tumor recurrence of laryngeal and hypopharyngeal carcinomas. STUDY DESIGN AND SETTING: Retrospective study on 341 patients treated by radiation alone or radiochemotherapy. The clinicopathologic findings, work-up, treatment, and follow-up of 20 patients with symptoms suggestive but negative for tumor recurrence on initial imaging studies and endoscopy were analyzed. RESULTS: The incidence of chondroradionecrosis in 341 irradiated patients was 5%. Ten of 20 patients initially negative for tumor recurrence were treated by total laryngectomy; in all laryngectomy specimens, chondroradionecrosis was present, in six specimens associated with tumor recurrence. Ten patients were treated by tracheotomy and tumor recurrence was detected in one patient during follow-up. CONCLUSION: Chondroradionecrosis is a relatively rare treatment complication. Typical imaging findings suggestive of radionecrosis are often missing. Tumor recurrence may be present beneath an intact mucosa and missed by endoscopy.
Abstract: BACKGROUND AND PURPOSE: The prognostic significance of laryngeal cartilage abnormalities, as seen on CT or MR imaging, in laryngeal or hypopharyngeal cancer, is unclear. The purpose is to determine whether cartilage abnormalities as seen on preoperative CT in laryngeal and pyriform sinus cancer are predictive of local outcome after partial laryngectomy. METHODS: The preoperative CT studies in a consecutive series of 16 patients who underwent extended hemilaryngectomy for squamous cell carcinoma of the glottis (n = 12), supraglottis (n = 1), or pyriform sinus (n = 3) were reviewed retrospectively. Cartilage abnormalities were defined as asymmetric cartilage sclerosis, lysis of ossified cartilage, or tumor visible on both sides of the cartilage. Tumor volume was calculated by using the summation-of-areas technique. Seven patients underwent postoperative radiation therapy. All patients had a follow-up of at least 24 months after treatment or until local recurrence. RESULTS: Eleven patients showed cartilage abnormalities. In six patients, only a single cartilage was abnormal, whereas three patients showed involvement of two cartilages and two patients of three cartilages. The overall average tumor volume was 2.7 mL; the average tumor volume was 1.5 mL in the patients without and 3.3 mL in those with cartilage involvement on CT (P > .05). Two patients suffered a local recurrence. One patient (tumor volume, 1.5 mL) did not show any cartilage abnormalities. The other patient (tumor volume, 1.9 mL) showed abnormalities in all three cartilages and also had evidence of early transcartilaginous tumor spread. CONCLUSION: In patients whose cancer is anatomically suitable for partial laryngectomy, cartilage abnormalities on CT do not preclude speech-preserving surgery.
Abstract: PURPOSE: To prospectively evaluate feasibility of diffusion-weighted (DW) magnetic resonance (MR) imaging in assessment of renal function in healthy volunteers and patients with various renal abnormalities and to prospectively evaluate reproducibility of DW MR imaging in volunteers. MATERIALS AND METHODS: Study protocol was approved by local ethics committee; informed consent was obtained. Eighteen healthy volunteers and 15 patients underwent transverse fat-saturated echo-planar DW MR imaging of the kidneys during normal breathing. Freehand regions of interest were delineated in the cortex and medulla of the kidneys. The following apparent diffusion coefficient (ADC) values were calculated: ADC of all b values (ADC(avg)), ADC of low b values (b = 0, 50, 100 sec/mm2; ADC(low)), and ADC of high b values (b = 500, 750, 1000 sec/mm2; ADC(high)). These values were calculated to differentiate influence of perfusion and diffusion. Reproducibility was assessed by repeating the same protocol in five randomly selected volunteers after 6 months. For statistical analysis, Student t tests were used. RESULTS: In all volunteers, ADC(avg) and ADC(high) were significantly higher in the cortex than in the medulla (P < .001). No difference between the cortex and medulla could be observed for ADC(low). Patients with renal failure had significantly lower ADC(avg) (P < .001, P = .004), ADC(low) (P = .02, P = .03), and ADC(high) (P = .02, P = .04) of cortex and medulla, respectively, than did volunteers. In the patient with pyelonephritis, all ADC values of cortex and medulla were substantially lower compared with the contralateral side, whereas patients with ureteral obstruction showed varying degrees of difference in all ADC values compared with the contralateral side. No statistically significant changes were found in the repeat study of the volunteers. CONCLUSION: DW MR imaging is feasible and reproducible in the assessment of renal function, as shown in our initial experience with a small number of patients and volunteers.
Abstract: PURPOSE: To evaluate diffusion-weighted magnetic resonance (MR) imaging for monitoring tumor response in rats after administration of combretastatin A4 phosphate. MATERIALS AND METHODS: Study protocol was approved by local ethical committee for animal care and use. Rhabdomyosarcomas implanted subcutaneously in both flanks of 17 rats were evaluated with 1.5-T MR unit by using four-channel wrist coil. Transverse T2-weighted fast spin-echo sequences, T1-weighted spin-echo sequences before and after gadodiamide administration, and transverse echo-planar diffusion-weighted MR examinations were performed before, 1 and 6 hours, and 2 and 9 days after intraperitoneal injection of vascular targeting agent (combretastatin A4 phosphate, 25 mg/kg). Apparent diffusion coefficient (ADC) was automatically calculated from diffusion-weighted MR imaging findings. These findings were compared with histopathologic results at each time point. For statistical analysis, paired Student t tests with Bonferroni correction for multiple testing were used. RESULTS: T1-weighted images before combretastatin administration showed enhancement of solid tumor tissue but not of central necrosis. At 1 and 6 hours after combretastatin injection, enhancement of solid tissue disappeared almost completely, with exception of small peripheral rim. At 2 and 9 days after combretastatin injection, enhancement progressively reappeared in tumor periphery. ADC, however, showed decrease early after combretastatin injection ([1.26 +/- 0.16]x 10(-3) mm2/sec before, [1.18 +/- 0.17]x 10(-3) mm2/sec 1 hour after [P=.0005] and [1.08 +/- 0.14]x 10(-3) mm(2)/sec 6 hours after [P=.0007] combretastatin A4 phosphate injection), histologically corresponding to vessel congestion and vascular shutdown in periphery but no necrosis. An increase of ADC ([1.79 +/- 0.13]x 10(-3) mm2/sec) (P <.0001) 2 days after combretastatin A4 phosphate injection was paralleled by progressive histologic necrosis. A significant (P <.0001) decrease in ADC 9 days after treatment ([1.41 +/- 0.15]x 10(-3) mm2/sec) corresponded to tumor regrowth. CONCLUSION: In addition to basic relaxation-weighted MR imaging and postgadolinium T1-weighted MR imaging to enable prompt detection of vascular shutdown, diffusion-weighted MR imaging was used to discriminate between nonperfused but viable and necrotic tumor tissues for early monitoring of therapeutic effects of vascular targeting agent.
Abstract: PURPOSE: To prospectively determine reproducibility of magnetic resonance (MR) angiography and MR spectroscopy of deoxymyoglobin in assessment of collateral vessels and tissue perfusion in patients with critical limb ischemia (CLI) and to follow changes in patients undergoing intramuscular vascular endothelial growth factor (pVEGF)-C gene therapy, percutaneous transluminal angioplasty, supervised exercise training, or no therapy. MATERIALS AND METHODS: Study and gene therapy protocols were approved, and all patients gave written informed consent. To determine repeatability and reproducibility, seven patients underwent MR angiography and five underwent MR spectroscopy. The techniques were used to judge disease progress in 12 other patients with or without therapy: MR angiography to help determine change in visualization of collateral vessels and MR spectroscopy to help assess change in perfusion at proximal and distal calf levels. MR angiographic results were subjectively analyzed by three blinded readers. Intraobserver variability was expressed as 95% confidence interval (CI) (n=7); interobserver variability, as kappa statistic (n=15). Reexamination variability of MR spectroscopy was given as 95% CI for subsequent recovery times, and correlation with disease extent was calculated with Kendall taub rank correlation. Fisher-Yates test was used to correlate changes with pressure measurements and clinical course. RESULTS: Intraobserver and interobserver concordance was sensitive for detection of collateral vessels. Intraobserver agreement was 85.7% (95% CI: 42.1%, 99.6%). Interobserver agreement was high for small collateral vessels (kappa=0.74, P <.001) and fair for large collateral vessels (kappa=0.36, P=.002). MR spectroscopy was reproducible (95% CI: +/-26 seconds for proximal, +/-21 seconds for distal) and showed a correlation with disease extent (proximal calf, taub=0.84, P <.001; distal calf, taub=0.68, P=.04). Small collateral vessels increased over time (P=.04) but did not correlate with pressure measurements and clinical course. Recovery time correlated with clinical course (proximal calf, P=.03; distal calf, P=.005). CONCLUSION: MR angiography and MR spectroscopy of deoxymyoglobin can help document changes in visualization of collateral vessels and tissue perfusion in patients with CLI.
Abstract: BACKGROUND: Invasion of the larynx by differentiated thyroid gland carcinoma is uncommon but causes serious morbidity and mortality when present. METHODS: The clinicopathologic characteristics of 5 patients in which a total laryngectomy had to be performed for differentiated thyroid carcinoma are analyzed. Special reference is paid to the histologic intralaryngeal tumor spread, which is evaluated on whole-organ section. RESULTS: All patients presented with hoarseness and/or dyspnea. Two patients are alive at 44 and 115 months. One patient died of intercurrent disease 2 months and 2 patients with disease 6 and 14 months after surgery. In all cases, intralaryngeal tumor spread was observed. Invasion of the larynx occurs by direct extension or by posterior tumor growth around the edge of the thyroid cartilage. CONCLUSION: In rare cases, differentiated thyroid carcinoma can widely infiltrate the larynx, making total laryngectomy unavoidable. The diagnosis of intralaryngeal tumor spread is done by imaging and endoscopy.
Abstract: Echo-planar diffusion-weighted (DW) magnetic resonance (MR) imaging was used to evaluate changes in the parotid glands during gustatory stimulation. The study protocol was approved by the local ethics committee, and informed consent was obtained from all volunteers. Twelve healthy volunteers (five women, seven men) with a median age of 25 years (range, 22-30 years) were examined with a 1.5-T MR unit. A DW MR imaging sequence was performed once at rest and continuously repeated over a mean period of 26 minutes (range, 24-28 minutes) during salivary stimulation with a tablet of ascorbic acid given orally. During the first 5 minutes (range, 1 minute 30 seconds--7 minutes 30 seconds) of salivary stimulation, a decrease in apparent diffusion coefficient (ADC) was observed in both the parotid (P = .0001) and the submandibular (P = .0004) glands in all volunteers. During the following 15 minutes, a steady increase in ADC from the baseline value was noted for the parotid glands (P = .0022), and peak ADC was reached a median of 21 minutes (range, 14-21 minutes) after the start of gustatory stimulation. The ADC of the submandibular glands did not increase significantly after the start of gustatory stimulation compared with the ADC at baseline. In conclusion, DW MR imaging allows physicians to noninvasively demonstrate functional changes in the salivary glands.
Abstract: The noninvasive assessment of anticancer treatment efficacy is very important for the improvement of therapeutic window. The purpose of the present study was to evaluate the antitumoral effects of the vascular targeting agent, combretastatin A-4 phosphate (CA-4-P), at selected time points after repeated intraperitoneal drug administrations (25 mg/kg), using diffusion-weighted magnetic resonance imaging (DW-MRI). The experiments were performed during an overall follow-up period of 3 weeks on WAG/Rij rats with subcutaneously growing rhabdomyosarcomas. Each animal served as its own baseline. The DW-MRI studies were quantified by calculating the apparent diffusion coefficient (ADC) for different low and high b-values to separate the effects on tumor vasculature and cellular integrity. The changes in ADC as well as the extent of necrosis development (proportional to the tumor volume), measured on the MR images, were of comparable magnitude after each treatment. All ADC values showed a significant decrease at 6 hours, followed by a significant increase at 2 days for various CA-4-P administrations. DW-MRI allowed us to monitor both reduction in perfusion and changes in the extent of tumor necrosis after CA-4-P injection. Repeated CA-4-P administration retains efficacy in rat rhabdomyosarcomas, with similar findings after each drug administration.
Abstract: PURPOSE: To compare dynamic contrast material-enhanced magnetic resonance (MR) imaging and diffusion-weighted MR imaging for noninvasive evaluation of early and late effects of a vascular targeting agent in a rat tumor model. MATERIALS AND METHODS: The study protocol was approved by the local ethics committee for animal care and use. Thirteen rats with one rhabdomyosarcoma in each flank (26 tumors) underwent dynamic contrast-enhanced imaging and diffusion-weighted echo-planar imaging in a 1.5-T MR unit before intraperitoneal injection of combretastatin A4 phosphate and at early (1 and 6 hours) and later (2 and 9 days) follow-up examinations after the injection. Histopathologic examination was performed at each time point. The apparent diffusion coefficient (ADC) of each tumor was calculated separately on the basis of diffusion-weighted images obtained with low b gradient values (ADC(low); b = 0, 50, and 100 sec/mm(2)) and high b gradient values (ADC(high); b = 500, 750, and 1000 sec/mm(2)). The difference between ADC(low) and ADC(high) was used as a surrogate measure of tissue perfusion (ADC(low) - ADC(high) = ADC(perf)). From the dynamic contrast-enhanced MR images, the volume transfer constant k and the initial slope of the contrast enhancement-time curve were calculated. For statistical analyses, a paired two-tailed Student t test and linear regression analysis were used. RESULTS: Early after administration of combretastatin, all perfusion-related parameters (k, initial slope, and ADC(perf)) decreased significantly (P < .001); at 9 days after combretastatin administration, they increased significantly (P < .001). Changes in ADC(perf) were correlated with changes in k (R(2) = 0.46, P < .001) and the initial slope (R(2) = 0.67, P < .001). CONCLUSION: Both dynamic contrast-enhanced MR imaging and diffusion-weighted MR imaging allow monitoring of perfusion changes induced by vascular targeting agents in tumors. Diffusion-weighted imaging provides additional information about intratumoral cell viability versus necrosis after administration of combretastatin.
Abstract: BACKGROUND: The normal left ventricle shows a systolic wringing motion with clockwise rotation at the base and counterclockwise rotation at the apex. PURPOSE: The aim of the present study was (1) to assess left ventricular (LV) contraction and relaxation in patients with chronic heart failure (CHF), and (2) to evaluate the effect of medical therapy on LV contraction-relaxation behavior. METHODS: Magnetic resonance was used to examine LV motion by labeling specific LV regions in three planes (myocardial tagging). Twenty-three subjects were included, nine healthy controls and 14 CHF patients. Cardiac motion was determined from the deformation of a rectangular grid in a basal and apical plane. CHF patients were put on triple therapy with ACE-inhibitors, beta-blockers and spironolactone. Follow-up examination (n=9) was performed after 6 months. RESULTS: In controls, systolic rotation was -9.5+/-2 degrees at the base and +3.3+/-1 degrees at the apex. In CHF patients, rotation was reduced both at the base (-3.4+/-2 degrees , P<0.01) and the apex (+0.9+/-3 degrees , P<0.05). Similarly, regional ejection fraction (REF) was reduced in CHF patients both at the base and the apex. Medical therapy was associated with an improvement in REF, but systolic rotation improved only at the base (-4.6+/-2 degrees , P<0.05). CONCLUSIONS: Systolic wringing motion with clockwise rotation at the base and counterclockwise rotation at the apex is maintained in CHF although reduced. Heart failure treatment is associated with an improvement in REF, whereas rotation improved only at the base, but not at the apex. Thus, there is an uncoupling between regional shortening and rotation in CHF patients.
Abstract: The aim of this study was to evaluate the appearance of the upper urinary tract following cystectomy and ileal orthotopic bladder substitution. Intravenous urograms (IVUs) performed preoperatively and at regular intervals postoperatively on 87 long-term survivors (minimum survival, 5 years) following ileal orthotopic bladder substitution were reviewed. Distention of the collecting system with blunted or rounded fornices was defined as dilatation. If in addition contrast medium excretion was delayed on the 5-min film, this was defined as obstruction. Collecting system dilatation was present on all IVU films obtained from most patients (80%) within 6 months of surgery, even in the absence of urinary tract obstruction. In contrast, dilatation was commonly seen only on the 20-min postinjection films (79%) on urograms performed more than 1 year following surgery, but not encountered on the other two postinjection radiographs (at 5 and 60 min). Five years after surgery, permanent obstruction was observed in only five (3%) renoureteral units. Dilatation of the upper urinary tract after ileal orthotopic bladder substitution is a frequent finding on the 5-min, 20-min, and 60-min films during the early postoperative period but is found only on the 20-min film 1 year and later after surgery. These findings should not be overinterpreted as obstruction.
Abstract: PURPOSE: To determine how the ADC value of parotid glands is influenced by the choice of b-values. MATERIALS AND METHODS: In eight healthy volunteers, diffusion-weighted echo-planar imaging (DW-EPI) was performed on a 1.5 T system, with b-values (in seconds/mm2) of 0, 50, 100, 150, 200, 250, 300, 500, 750, and 1000. ADC values were calculated by two alternative methods (exponential vs. logarithmic fit) from five different sets of b-values: (A) all b-values; (B) b=0, 50, and 100; (C) b=0 and 750; (D) b=0, 500, and 1000; and (E) b=500, 750, and 1000. RESULTS: The mean ADC values for the different settings were (in 10(-3) mm2/second, exponential fit): (A) 0.732+/-0.019, (B) 2.074+/-0.084, (C) 0.947+/-0.020, (D) 0.890+/-0.023, and (E) 0.581+/-0.021. ADC values were significantly (P <0.001) different for all pairwise comparisons of settings (A-E) of b-values, except for A vs. D (P=0.172) and C vs. D (P=0.380). The ADC(B) was significantly higher than ADC(C) or ADC(D), which was significantly higher than ADC(E). ADC values from exponential vs. logarithmic fit (P=0.542), as well as left vs. right parotid gland (P=0.962), were indistinguishable. CONCLUSION: The ADC values calculated from low b-value settings were significantly higher than those calculated from high b-value settings. These results suggest that not only true diffusion but also perfusion and saliva flow may contribute to the ADC.
Abstract: Reflex otalgia is a predictive and prognostic parameter for local control in patients with oropharynx carcinoma. Can a morphologic correlate of this important symptom be detected by MRI? Thirty-six patients were prospectively evaluated by MRI before radical radiotherapy. Sixteen patients had reflex otalgia; 20 did not. The oropharynx and adjacent regions were analyzed. Alteration was defined as effacement of anatomical structures, signal alteration or enhancement after contrast medium administration. The chi(2)-test was used to compare categorical parameters. In patients with reflex otalgia, alteration of the following structures innervated by the glossopharyngeal nerve were found significantly more often: nasopharynx, hard palate, superior constrictor pharyngis muscle, palatine tonsil, palatopharyngeus muscle, palatoglossus muscle, stylopharyngeus muscle, hyoglossus muscle and preepiglottic space. No difference was found for the muscles of mastication, levator and tensor veli palatini muscles, styloglossus muscle, genioglossus muscle, intrinsic muscles of the tongue, digastric muscles, mucosal surface of the lateral and posterior pharyngeal wall, uvula, valleculae, parapharyngeal space and larynx. An alteration of structures innervated by the glossopharyngeal nerve was visualized on MRI significantly more often when reflex otalgia was present. Involvement of structures innervated by other cranial nerves did not show the same association with ear pain.
Abstract: PURPOSE: Ileal conduit is considered a safe procedure and the gold standard to which newer forms of urinary diversion should be compared, although few long-term results are known. We analyzed a consecutive series of patients who lived a minimum of 5 years after ileal conduit diversion. MATERIALS AND METHODS: A total of 412 patients underwent ileal conduit diversion between 1971 and 1995 at our institution. We analyzed all conduit related complications occurring later than 3 months after surgery in 131 long-term survivors (survival 5 years or greater). RESULTS: Median followup was 98 months (range 60 to 354). Overall 192 conduit related complications developed in 87 of 131 (66%) patients. The most frequent complications were related to kidney function/morphology in 35 patients (27%), stoma in 32 (24%), bowel in 32 (24%), symptomatic urinary tract infection (including pyelonephritis) in 30 (23%), conduit/ureteral anastomosis in 18 (14%) and urolithiasis in 12 (9%). Within the first 5 years complications developed in 45% of patients. This percentage increased to 50%, 54% and 94% in those surviving 10, 15 and longer than 15 years, respectively. In this last group 50% had upper urinary tract changes and 38% had urolithiasis, for which the respective numbers after 5 years were 12% and 17%. CONCLUSIONS: This study demonstrates a high conduit related complication rate in long-term survivors and underlines the need for vigorous long-term followup. Only studies lasting more than 1 decade cover the entire morbidity spectrum.
Abstract: Unenhanced spiral computed tomography is now applied in the investigation of patients with acute flank pain to search for suspected urinary tract calculi. Spiral CT can depict urinary calculi more accurately than plain radiographs, sonography or excretory urography, and can be performed using a low dose protocol. Almost all urinary calculi, including calculi composed of uric acid, xanthine and cystine, can be detected. In addition to determining size and location of the stone, unenhanced helical CT can predict its composition. Furthermore, it reveals secondary signs of obstruction, such as dilatation of the renal collecting system and perinephric stranding. In the absence of urolithiasis, CT can frequently detect or exclude other causes of acute flank pain, thus guiding subsequent imaging and the therapeutic management.
Abstract: The choice of the most suitable technique for radiologic evaluation of upper urinary tract stones depends on the precise clinical questions that have to be answered. Many of these questions can still be answered by plain films of the abdomen and excretory urography. This review addresses the value of ultrasonography and computed tomography (CT) with respect to the two most important clinical questions, i.e. 1) presence/extent of obstruction/hydronephrosis and perinephric abscess in patients with acute flank pain; and 2) precise location, number and size of calculi. Because its sensitivity is comparable with CT and it is widely available, ultrasonography in the hands of experienced clinicians/radiologists may be preferred for evaluation of patients with acute flank pain. However, it must be emphasized that ultrasonography may totally miss acute ureteral obstruction/hydronephrosis within the first 12-24 hours. In children as well as in pregnant women, ultrasonography is still the technique of choice, but it may be replaced by magnetic resonance urography in the future. For precise stone location or detection of calcifications, however, the speed, safety and accuracy of unenhanced helical CT make this the most sensitive method and therefore the technique of choice. It also detects urinary calculi more accurately and exposes patients to less radiation than the traditional combined plain abdominal film/intravenous urography. Furthermore, CT can most readily reveal alternative diagnoses in patients with acute flank pain and other intraabdominal pathologies than stones.
Abstract: PURPOSE: We determine long-term morphological changes of the upper urinary tract following ileal orthotopic bladder substitution with an afferent tubular segment without a flap-valve type antireflux procedure. MATERIALS AND METHODS: A consecutive series of long-term survivors (5 years or greater) following ileal orthotopic bladder substitution underwent regular radiological followup with excretory urography. Preoperative and postoperative renal size, parenchymal thickness, pelvicaliceal dilatation and upper urinary tract obstruction were assessed by 2 radiologists. RESULTS: A total of 76 patients with a median followup of 84 months (range 60 to 155) were evaluable. Four patients (2.6%) underwent unilateral nephroureterectomy during followup. Of the remaining 148 renoureteral units 141 (95%) revealed no significant changes in size or parenchymal thickness during followup. Renal size decreased in 6 (4%) and parenchymal thickness in 7 (5%) renoureteral units, 5 of which already had renal pathologies (dilatation, obstruction or hypoplastic kidney) preoperatively. De novo shrinkage of the parenchyma of a preoperatively normal kidney was observed in 2 (1%) renoureteral units associated with stenosis of the ureteroileal anastomosis. Of the 148 renoureteral units 14 (9%) presented with nonobstructive dilatation and 4 (3%) with complete obstruction. Preoperatively average serum creatinine level +/- SD was 98 +/- 19 micromol./l. and 10 years thereafter it was 83 +/- 27 micromol./l. CONCLUSIONS: These data suggest that unidirectional peristalsis of ureters and the afferent tubular ileal segment sufficiently protect the upper urinary tract following ileal bladder substitution up to a decade provided there are no preoperative renal pathology and no anastomotic stricture postoperatively. Additional antireflux flap-valve type implantation techniques are not required.
Abstract: OBJECTIVE: The objective of this study was to test the clinical value of MR imaging for diagnosing cephalopelvic disproportion and for predicting labor outcome in women at risk for dystocia. SUBJECTS AND METHODS: Antepartum fetal sonography and maternal MR imaging pelvimetry measurements were performed at term in 38 pregnant women at risk for dystocia with a single fetus in cephalic presentation. Various methods used to diagnose cephalopelvic disproportion were evaluated in a blinded manner for their accuracy to predict both the presence of cephalopelvic disproportion and the mode of delivery (vaginal vs cesarean). RESULTS: None of the methods tested yielded both high sensitivity (15-100%) and high specificity (24-92%) for determining the presence of cephalopelvic disproportion and high levels of accuracy for predicting labor outcome (overall predictability, 50-74%). CONCLUSION: To achieve increased reliability of MR imaging pelvimetry in the diagnosis and treatment of dystocia and in predicting labor outcome, new methods assessing fetal-pelvic compatibility, including measurements of the pelvic outlet and the shape and configuration of the pelvis, need to be established and prospectively tested before firm recommendations for clinical use can be made.
Abstract: PURPOSE: A controlled trial was performed to compare non-invasive multislice CT (virtual laryngoscopy, axial CT slices, coronal and sagittal reformats) in the detection and grading of upper airway stenosis with fiberoptic laryngoscopy. MATERIAL AND METHODS: Multislice CT and fiberoptic laryngoscopy were used to examine 111 upper airway sections (supraglottis, glottis, subglottis, trachea) in 29 patients. CT data were acquired on a multirow detector CT (collimation 4 x 1 mm, reconstruction interval 1 mm, IV contrast) and postprocessing was performed using multiplanar reformatted images (MPR) and virtual laryngoscopy. RESULTS: All CT methods accurately detected upper airway stenosis (accuracy was 96 % for virtual laryngoscopy and MPR and 94 % for axial CT-slices). Correlation of fiberoptic and virtual laryngoscopy (r = 0.94) for grading of stenosis was closer than with sagittal reformats (r = 0.80), coronal reformats (r = 0.72), and axial CT slices (r = 0.57). Even high grade stenosis could be passed with virtual laryngoscopy that was impassable for fiberoptic laryngoscopy. CONCLUSIONS: Virtual laryngoscopy enabled better assessment of stenosis as compared to reading of axial CT slices or MPR. Virtual laryngoscopy is complementary to fiberoptic laryngoscopy and should be combined with axial CT slices and MPR readings for evaluation of the surrounding structures.
Abstract: In children with renal tubular disorders the existence of retarded histological features of glomerular maturation has been suggested by our group. However, no valuable information is available on the frequency of histopathologically immature glomeruli in the normal kidney. For this reason we established a simple, semiquantitative definition of postnatal glomerular development: immature glomeruli (with at least half of the circumference of capillary loops densely lined with cuboidal epithelial cells), intermediate glomeruli (circumference of capillary loops lined with at least five adjoining cuboidal cells), and mature glomeruli. This definition was applied in a set of 71 normal kidneys from ages birth to 5 years. The relative frequency of the mentioned stages of glomerular maturation was strongly age dependent. In comparing the patients data with the normal findings it was possible to separate patients with the finding of disproportionately high fractions of immature glomeruli, provided the right age at biopsy is chosen. It is therefore concluded that the previous suspicion of late glomerular maturation may be validated in at least in some bioptic specimens.
