Abstract: PURPOSE OF REVIEW: The utility of positron emission tomography-computed tomography has increasingly been studied during the last years. Positron emission tomography-computed tomography offers a holistic approach of cancer diagnosis as it can integrate structural, functional, metabolic, and molecular information of tumour. The technique offers three-dimensional, high-resolution, whole body, and quantitative imaging. 18F-Fluoro-2-deoxy-D-glucose still remains the only tracer widely available. Other tracers have been designed for assessment of proliferation, amino acid uptake, and hypoxia. RECENT FINDINGS: 18F-Fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography seems the most appropriate technique for the assessment of locoregional lymph node involvement in head and neck cancer. False negativity of positron emission tomography-computed tomography in case of micrometastatic lymph node disease should be compensated by the implementation of the sentinel node scintigraphy guided biopsy. 18F-Fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography has a very high sensitivity and negative predictive value in detecting residual disease after radiotherapy or early recurrent disease. Radiotherapy planning can use the 18F-fluoro-2-deoxy-D-glucose uptake distribution for increasing the accuracy of delineation of the target volumes in conformal radiotherapy. Positron emission tomography-computed tomography with other tracers such as deoxy-18F-fluorothymidine for proliferation mapping and [F-18] fluoromisonidazole for hypoxia mapping are currently being studied. SUMMARY: Major studies have now confirmed the utility of positron emission tomography-computed tomography in the different phases of diagnostic and therapeutic phases of the management of patients with head and neck cancer.
Abstract: The clinical added-value of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18FDG PET) in the management of oncology patients is increasingly documented. In the present review, we discuss both the benefits and the limitations of 18FDG PET in different cancers. Considering the literature data and our own experience, we also indicate the best clinical approach to optimize the use of metabolic imaging in oncology.
Abstract: Colorectal cancer is a severe disease with a significant incidence in Western world. In the course of disease, about 40% of patients will eventually develop metastases to the liver. The majority of them will never be candidate for curative surgical management. For those patients, systemic or intra-hepatic chemotherapy is the treatment's cornerstone. Unfortunately, despite evident improvements and apparition of several active new agents, no hope of cure emerges on the agenda for now. Hepatic intra-arterial injections of radioactive devices have since a long time drawn interest from the medical community. An anti-tumoural activity has been demonstrated with Yttrium-loaded microspheres injected in the hepatic artery for several liver neoplasms including metastases from colorectal cancer. We lack however the results of large randomized phase III trials to define clearly the place of those interventional therapies in the management of colorectal cancer metastatic to the liver.
Abstract: BACKGROUND: Lhermitte-Duclos disease is a cerebellar lesion, characterized by an overgrowth of cerebellar ganglion cells, which replace granular cells and Purkinje cells. Lhermitte-Duclos disease may be a manifestation of Cowden syndrome (multiple hamartoma-neoplasia syndrome). The nature of LDD, whether neoplastic, dysplastic, or hamartomatous, is still not exactly understood. Metabolic imaging of the amino acid metabolism using PET could be useful for noninvasive characterization of these lesions. METHODS: To define the Meth-PET imaging characteristics of these lesions, we undertook a Meth-PET study in 4 patients with LDD after obtaining informed consent. All 4 patients had clinical signs of Cowden syndrome. In 2, the diagnosis was made with MRI; in 2, it was confirmed histologically. RESULTS: Using Meth-PET, the cerebellar lesions had a high methionine uptake, except in the subtotally resected lesion. The uptake of the lesions was markedly higher than that of the contralateral normal regions. The mean L/C ratio was 2.07. CONCLUSION: 11C-methionine positron emission tomography visualizes the lesion of Lhermitte-Duclos disease as a high uptake area. This amino acid hypermetabolism may be related to the slow growth of the lesions, and is an argument to suggest that patients with LDD should be followed up carefully to detect progression of the cerebellar lesion.
Abstract: INTRODUCTION: Sentinel lymph node biopsy is a new technique in staging the clinically NO neck. Tumour spread to the neck is the most important prognostic factor in head and neck squamous cell carcinoma (HNSCC). MATERIAL AND METHODS: Patients with histologically confirmed HNSCC, with no clinical and no radiological (CT or MRI) evidence of cervical lymph node involvement were eligible for this prospective study. The lymph node mapping was performed by preoperative lymphoscintigraphy and intraoperative use of hand-held gamma probe. Four injections (with Tc 99m-labeled nanocolloids) were performed around the primary tumour. The SLN, as indicated by dynamic scintigraphy and the neck dissection specimen, were sent separately for histological analysis. The presence of occult metastasis in the SLN and in the neck dissection specimen were compared. RESULTS: Ten consecutive patients (8 males ; 2 females) with a mean age of 61 years (range 47 to 74 years) were prospectively entered into the study. The primary tumour was located on the oral tongue in 4 cases, in the floor of the mouth in 5 cases and in the oropharynx in 1 case. Primary tumours were staged T2 in nine cases, one tumour was staged T1 according to UICC 1997. All the tumours were clinically staged cN0 by palpation and computed tomography (or MRI). Lymphoscintigraphy was performed and revealed a SLN in all cases. The sentinel node biopsy technique permitted an upstaging of the clinically cN0 neck in 3/10 cases. The SLN technique was false negative in one patient with a skip metastasis. CONCLUSION : SLN evaluation in HNSCC is feasible and provides a highly accurate staging of NO necks in oral and oropharyngeal carcinomas.
Abstract: Dermatofibrosarcoma protuberans is a soft-tissue tumor that may recur locally and rarely causes metastases to vital organs. Dermatofibrosarcoma protuberans has specific chromosomal abnormalities involving the platelet-derived growth factor beta-chain locus that may render these tumors responsive to targeted therapy with the tyrosine kinase inhibitor imatinib mesylate. A patient with locally recurrent and metastatic dermatofibrosarcoma protuberans who had already undergone surgery 22 times was initially treated with imatinib mesylate 400 mg/day. The treatment dose was increased after 7 days to 400 mg twice daily. The patient was followed up for response and toxicity by physical examination and imaging studies, comprising computed tomography and fluorodeoxyglucose positron emission tomography. Clinical response could be demonstrated after the first month of treatment, and subsequent computed tomography and positron emission tomography documented a response to imatinib mesylate therapy. Our patient is now in sustained remission with minimal toxicity. We conclude that antitumor activity of metastatic dermatofibrosarcoma protuberans can be obtained with imatinib mesylate treatment with minimal side-effects.
Abstract: Merkel cell carcinoma (MCC) is a rare and highly malignant skin cancer with neuroendocrine differentiation. We studied the potential value of 18FDG PET in the management of MCC. Eleven patients with MCC were examined by 18FDG PET and PET-CT for staging purpose (n=4) or for detection of recurrence (n=7). Qualitative and quantitative interpretation of PET studies was performed routinely. 18FDG PET observations were compared to clinical and radiological findings. In 6 patients, PET findings were also compared to histology. In 7 patients, the 18FDG tumor uptake was compared to the MCC proliferative activity expressed by the Ki-67 index. 18FDG PET was contributive in 10/11 MCC patients. In 7 patients, 18FDG PET detected focal lesions or a disseminated stage of the disease including dermal, nodal and visceral metastases. In 3 patients, a normal 18FDG PET confirmed complete remission of disease. Most MCC patients exhibited highly 18FDG-avid sites suggestive of increased glucose metabolism. This imaging pattern was related to a high proliferative activity (Ki-67 index >50%). In 1 patient with a weakly proliferative nodal MCC (Ki-67<10%), a false negative result was yielded by metabolic imaging. In 4/11 patients, 18FDG PET revealed an unsuspected second neoplasm in addition to MCC. It is concluded that whole-body 18FDG PET may be useful in the management of MCC patients. However, a normal 18FDG PET aspect cannot rule out MCC with low proliferative activity.
Abstract: PURPOSE: 18F-fluorodeoxyglucose (FDG) and 11C-methionine (MET) PET imaging studies allow the investigation of metabolism and amino acid transport in brain tumours. Their (relative) usefulness and prognostic value in suspected recurrence or progression of primary brain tumours after previous therapy is an issue of debate. The aim of this study was to compare directly both radioligands in this setting. METHODS: Cerebral uptake of FDG and MET was determined sequentially on the same day in 30 patients (21 males, nine females; age 40.4+/-15.6 years), on average 4.0 years (range 0.1-18) after therapy for a primary brain tumour (23 grade II-IV astrocytomas, four oligodendrogliomas and three mixed oligo-astrocytomas). Images were acquired on a Siemens HR+ dedicated PET camera. Two observers scored FDG and MET scans independently. Semi-quantitative indices defined by the tumour (maximum)-to-background ratio were calculated based on manual ROI delineation and by using MET ROIs for FDG after automated co-registration. Patient follow-up was conducted until the last contact with inconspicuous clinical findings (average 41 months, range 12-62 months after PET) [(n=10)] or until death (n=20). RESULTS: Overall median survival was 15.0 months. MET showed pathologically increased uptake in 28/30 scans, and FDG in 17/30. The inter-observer agreement was 100% for MET and 73% for FDG. Using Kaplan-Meier survival analysis, significant differences were found for both FDG (cut-off 0.8, log-rank p=0.007) and MET (cut-off 2.2, log-rank p=0.014). The combination of FDG and MET information resulted in the highest prognostic accuracy (p=0.003), while MET alone was the best prognostic predictor in the subgroup of patients with primary astrocytoma (n=23). CONCLUSION: FDG and MET PET studies provide complementary prognostic information in patients with suspected brain tumour recurrence or progression after primary therapy. MET is considered the single agent of choice in the evaluation of these patients because of its sensitivity and clearer delineation of the suspected recurrence.
Abstract: PURPOSE OF REVIEW: Positron emission tomography using 18F-fluoro-2-deoxy-D-glucose (18FDG-PET) is well established in clinical routine as a metabolism-based whole-body imaging tool for cancer diagnosis and follow-up. Several reports have appeared indicating the potential and limitations of this technique in head and neck cancer (HNC). This review limits its scope to the recent advances using 18FDG-PET in the clinical management of HNC. RECENT FINDINGS: The combination of 18FDG-PET and sentinel node biopsy has been explored for the surgical treatment planning of oral and oropharyngeal cancer. Recent reports indicate that multimodality imaging combining PET with high-end CT scanning increases the diagnostic accuracy. 18FDG-PET has a potential for use in radiation treatment planning and for the prediction of response and early evaluation of treatment efficacy. SUMMARY: Increasingly 18FDG-PET is used as a clinical imaging modality in the different stages of the management of HNC. In particular, its clinical value in initial staging of neck lymph nodes and in the evaluation of recurrent or residual disease is well established. In these settings 18FDG-PET has been shown to be more accurate than conventional imaging. Recent studies indicate that 18FDG-PET could be of additional value in staging the N0 neck, in radiation treatment planning, and in prediction of treatment efficacy.
Abstract: PURPOSE: The presence of lymph node involvement (N) and distant metastasis (M) in patients with invasive bladder carcinoma is a major determinant of survival and, therefore, a pivotal element in the therapeutic management. The aim of this prospective study was to evaluate the use of( 18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in this indication. METHODS: Whole-body FDG-PET and computed tomography (CT) were performed in 55 patients with non-metastatic invasive bladder cancer for preoperative staging. Correlative imaging of PET with CT was performed, leading to a PET(CT) result. The imaging results were compared with the gold standard, consisting of histopathology (lymphadenectomy, guided biopsy) or clinical follow-up for 12 months, and related to overall survival using the Kaplan-Meier method. RESULTS: The gold standard was available in 40 patients and indicated NM-positive disease in 15 patients (12 N lesions, 8 M lesions), and NM-negative disease in 25 patients. For the diagnosis of NM-positive disease, the sensitivity, specificity and accuracy of PET(CT) were 60%, 88% and 78%, respectively. Diagnostic discordances between PET(CT) and CT alone were found in 9/40 patients, among whom PET was correct in six (15%): three with true-positive and one with true-negative distant metastases, and two with true-negative lymph nodes. Median survival time of patients in whom PET(CT) indicated NM-positive disease was 13.5 months, compared with 32.0 months in the patients with a NM-negative PET(CT) (p=0.003). CONCLUSION: Addition of metabolism-based information provided by FDG-PET to CT in the preoperative staging of invasive bladder carcinoma yields a high diagnostic and prognostic accuracy.
Abstract: Positron emission tomography (PET) using the positron emitting glucose analogue 18F-fluorodeoxyglucose (FDG) has emerged as a useful metabolism-based wholebody imaging tool for gastro-esophageal cancer diagnosis and follow up. Most large cancer centers worldwide are now equipped for PET (or even PET-CT). Therefore, there is a growing need for a clear definition of the relative position of PET within the currently available diagnostic modalities. Significant scientific data indicate that FDG-PET adds clinically useful information to the information obtained by standard means (mainly CT and endoscopic ultrasound) throughout the different phases of clinical patient management: 1) at initial diagnosis: PET detects more frequently distant lymph node involvement and organ metastases compared to conventional diagnostics, allowing a more accurate selection of the most appropriate treatment; 2) during chemotherapy: semi-quantitative FDG-PET allows early identification of non-responding patients. Indeed, the metabolic response as measured by serial FDG-PET can be used to predict the clinical and histopathological response. Moreover, the PET-response seems to be related to overall and disease free survival; 3) after a treatment: FDG-PET allows accurate assessment of the residual tumor load; 4) in the follow up: FDG-PET allows accurate detection and restaging of recurrent disease.
Abstract: PURPOSE OF REVIEW: Positron emission tomography using the positron emitting glucose analogue 18F-fluorodeoxyglucose has recently emerged as a promising metabolism-based whole-body imaging tool for cancer diagnosis and follow-up. Several reports have recently appeared indicating the potential and limitations of this technique. The review limits its scope to the recent advances of 18F-fluorodeoxyglucose positron emission tomography in the clinical management of gastric and esophageal cancer. RECENT FINDINGS: New studies have been reported on the use of 18F-fluorodeoxyglucose positron emission tomography to assess the early and late metabolic response of a gastroesophageal tumor to chemo(radiation) therapy. The metabolic response as measured by serial 18F-fluorodeoxyglucose positron emission tomography, performed before and during treatment or some weeks thereafter, can be used to predict the clinical and histopathologic response. Moreover, the metabolic positron emission tomography response seems to be related to overall and disease-free survival. SUMMARY: Gastroesophageal 18F-fluorodeoxyglucose positron emission tomography could add significant diagnostic information to the different phases of patient management. At initial diagnosis of esophageal cancer, positron emission tomography detects more distant lymph node and organ metastases compared with conventional diagnostics, allowing a more accurate selection of the most appropriate treatment. Serial 18F-fluorodeoxyglucose positron emission tomography performed before and during chemotherapy allows early identification of nonresponding tumors. 18F-fluorodeoxyglucose positron emission tomography performed after a treatment allows accurate assessment of the residual tumor load. 18F-fluorodeoxyglucose positron emission tomography allows accurate detection and restaging of recurrent disease.
Abstract: BACKGROUND: Studies combining pH and Bilitec monitoring found a high prevalence of both acid and duodeno-gastro-oesophageal reflux in severe reflux disease. Clearance of refluxed material is a major defence mechanism against reflux. Several studies have been devoted to oesophageal acid clearance but oesophageal clearance of refluxed duodenal contents (DC) has rarely been addressed. Aim: To compare oesophageal acid and DC clearance. METHODS: Ten healthy volunteers (five women, mean age 23 (1) years) were studied. Firstly, a balloon tip catheter, positioned in the duodenum under fluoroscopy, was used to aspirate DC after stimulation by a high caloric liquid meal (200 ml, 300 kcal). During the second session, pH and Bilitec probes were positioned 5 cm above the lower oesophageal sphincter and a small infusion catheter was introduced into the proximal oesophagus. The subject was placed supine under a gamma camera. One of two different solutions (DC mixed with 0.2 mCi Tc99m pertechnetate or citric acid (pH 2) mixed with 0.2 mCi Tc99m pertechnetate) was infused into the proximal oesophagus and the subject was instructed to swallow at 20 second intervals. Clearance was assessed using scintigraphy (dynamic acquisition, one frame per second in the anterior view; calculation of time to clear peak counts to background level), pH (time to pH<4) or Bilitec (time absorbance >0.14) monitoring, with or without continuous saliva aspiration. Each condition was studied twice in a randomised design; measurement time was four minutes, interrupted by water flushing, with a two minute rest period. Results are given as mean (SEM) and were compared by Student's t test and Pearson correlation. RESULTS: Scintigraphic evaluation showed a volume clearance time of 29 (3) seconds for acid and 28 (9) seconds for DC (NS). Saliva aspiration had no significant influence on volume clearance of acid or DC (28 (4) and 30 (13) seconds, respectively; NS). pH monitoring showed an acid clearance time of 217 (15) seconds, which was significantly prolonged to 324 (30) seconds during saliva aspiration (p<0.05). Bilitec monitoring showed a DC clearance time of 131 (27) seconds, which was not significantly prolonged by saliva aspiration (176 (36) seconds; p = 0.08). DC clearance was faster than acid clearance, either without or with saliva aspiration (p<0.055 and p<0.05, respectively). CONCLUSIONS: Under experimental conditions, liquid acid and DC solutions have comparable volume clearances. Chemical clearance occurs slightly faster for DC than for acid, and saliva plays a major role in the clearance of acid only.
Abstract: BACKGROUND AND PURPOSE: To determine the salivary function, after parotid-sparing radiotherapy (RT), of different regions within the parotid gland and to evaluate dose-function relationships within the parotid glands and between patients. PATIENTS AND METHODS: Sixteen head and neck cancer patients, irradiated between September 1999 and November 2000 using a conformal parotid-sparing technique, were included in this study. Before RT and 7 months after RT (range 6-10 months), a salivary gland scintigraphy was performed in all patients combined with a single photon emission computed tomography (SPECT). The salivary excretion fraction (SEF) was measured, after stimulation, in 8-12 transverse 5mm SPECT slices of each parotid. Loss of salivary excretion fraction (dSEF %) of these slices was calculated as the proportion of SEF after RT as compared to SEF before RT. Since the planning CT-scan and the SPECT-scintigraphy were performed in the same treatment position, the dose to a transverse slice within the parotid gland could be matched to the loss of salivary excretion fraction of that respective slice. A non-linear model was fitted to the dose-loss of function data and the dose resulting in 50% loss of salivary excretion fraction (D50) was calculated. RESULTS: Before RT, all but one patient presented with normal salivary excretion fractions (SEF) of both parotid glands. Within the same parotid gland, the SEF's of the different slices were almost equal. Seven months after RT, the reduction in SEF was statistically significant (P-value<0.0001). A significant difference in loss of salivary excretion fraction (dSEF) was also observed between both parotid glands (P<0.0001) as a result of the parotid-sparing technique. When plotting the dSEF of a slice versus the dose given to that slice, doses as low as 10-15 Gy could result in a serious loss of function (dSEF>50%). After fitting a non-linear model to these plots, the mean dose resulting in 50% loss of salivary excretion fraction (D50) 7 months after RT was 22.5 Gy. A large inter-patient variability was found in D50. CONCLUSIONS: Salivary SPECT is a useful tool for the evaluation of the salivary function of different slices within the parotid gland. Before irradiation, the different slices within one parotid gland act as functional sub-units contributing equally to the function of the entire gland. Seven months after an average dose of 22.5 Gy (D50) the functional sub-unit has lost 50% of its excretion fraction. The high inter-patient variability in D50 and the observation that low doses (10-15 Gy) can induce serious loss of function should prompt us in the clinic to reduce the dose to the parotids even lower than the threshold of 22.5 Gy.
Abstract: BACKGROUND AND PURPOSE: To determine the additional value of FDG-positron emission tomography (PET) to optimize delineation of the clinical target volume (CTV) in patients with advanced esophageal carcinoma. METHODS AND MATERIALS: The imaging and radiotherapy data from 30 patients with an advanced esophageal carcinoma were analysed. The lymph node classification for esophageal cancer was modified and translated into anatomical volumes on computed tomography (CT). The so defined 14 different regions were scored individually for lymph node involvement on CT, endoscopic ultrasound (EUS) and FDG-PET. The influence of discordant findings between conventional and functional imaging on the decision as to what should be irradiated was assessed. RESULTS: In 14 of the 30 patients (47%) discordances were found in detection of the pathological lymph nodes between CT/EUS and FDG-PET. In 8 patients, 9 lymph node regions were found with pathologic nodes on conventional imaging only. In three of these patients the influence of FDG-PET findings would have led to a decrease of the irradiated volume. In 6 patients, 8 lymph node regions were found with a normal CT/EUS and pathologic nodes on FDG-PET. In three of these patients (10%) the influence of the FDG-PET would have led to enlargement of the irradiated volume. CONCLUSIONS: The chance of a false negative result on FGD-PET is not negligible; therefore, the irradiated volume should not be reduced based on a negative FDG-PET in a region with suspect nodes on other investigations. However, due to the high specificity of FDG-PET enlarging the irradiated volume based on a positive FDG-PET in a region without suspected lymph nodes on CT and/or EUS should be considered. This indicates a role for FDG-PET in radiotherapy planning for esophageal cancer.
Abstract: Treatment of malignant glioma is difficult and discouraging. Even after resection and maximal adjuvant therapy, the prognosis remains poor. The authors sought a novel form of treatment, such as stimulating the patient's own immune response against the tumor, and developed a protocol of tumor vaccination in which autologous dendritic cells (DCs) were used in patients with recurrent malignant glioma. A 4-year-old girl was treated by means of biopsy sampling and radiotherapy for a rolandic low-grade glioma. Ten years later, a Grade III recurrence was discovered and treated with subtotal resection, interstitial radiation, six courses of oral temozolomide, and 12 courses of oral VP 16. At the end of the chemotherapy cycle, a new rapidly growing recurrence was diagnosed. A macroscopically complete resection was performed. Afterward, the girl was vaccinated with autologous DCs that had been pulsed ex vivo with the homogenate of the resection specimen. She received six vaccines in total. The efficacy of immunization was checked by a positive delayed-type hypersensitivity skin reaction after the second injection. After the fifth vaccine, a transient contrast enhancement without mass effect was visualized on magnetic resonance imaging. Simultaneously, positron emission tomography imaging revealed a transient increase of metabolic activity around the resection cavity, but the metabolic uptake ratio remained below 1.8. The patient's disease is still in complete remission 24 months after the last surgery. She is clinically well with minor and stable left hemiparesis. This case report illustrates the potential of vaccination with DCs loaded with crude tumor homogenate as adjuvant therapy to induce prolonged tumor control of malignant glioma and the objective noninvasively monitored immune response against infiltrating tumor cells.
Abstract: This study aimed to evaluate tumour hypoxia by comparing [(18)F]Fluoromisonidazole uptake measured using positron emission tomography ([(18)F]FMISO-PET) with immunohistochemical (IHC) staining techniques. Syngeneic rhabdomyosarcoma (R1) tumour pieces were transplanted subcutaneously in the flanks of WAG/Rij rats. Tumours were analysed at volumes between 0.9 and 7.3 cm(3). Hypoxic volumes were defined using a 3D region of interest on 2 h postinjection [(18)F]FMISO-PET images, applying different thresholds (1.2-3.0). Monoclonal antibodies to pimonidazole (PIMO) and carbonic anhydrase IX (CA IX), exogenous and endogenous markers of hypoxia, respectively, were used for IHC staining. Marker-positive fractions were microscopically measured for each tumour, and hypoxic volumes were calculated. A heterogeneous distribution of hypoxia was observed both with histology and [(18)F]FMISO autoradiography. A statistically significant correlation (P<0.05) was obtained between the hypoxic volumes defined with [(18)F]FMISO-PET and the volumes derived from the PIMO-stained tumour sections (r=0.9066; P=0.0001), regardless of the selected threshold between 1.4 and 2.2. A similar observation was made with the CA IX staining (r=0.8636; P=0.0006). The relationship found between [(18)F]FMISO-PET and PIMO- and additionally CA IX-derived hypoxic volumes in rat rhabdomyosarcomas indicates the value of the noninvasive imaging method to measure hypoxia in whole tumours.
Abstract: Patients with relapsed malignant glioma have a poor prognosis. We developed a strategy of vaccination using autologous mature dendritic cells loaded with autologous tumour homogenate. In total, 12 patients with a median age of 36 years (range: 11-78) were treated. All had relapsing malignant glioma. After surgery, vaccines were given at weeks 1 and 3, and later every 4 weeks. A median of 5 (range: 2-7) vaccines was given. There were no serious adverse events except in one patient with gross residual tumour prior to vaccination, who repetitively developed vaccine-related peritumoral oedema. Minor toxicities were recorded in four out of 12 patients. In six patients with postoperative residual tumour, vaccination induced one stable disease during 8 weeks, and one partial response. Two of six patients with complete resection are in CCR for 3 years. Tumour vaccination for patients with relapsed malignant glioma is feasible and likely beneficial for patients with minimal residual tumour burden.
Abstract: Positron emission tomography (PET) using (18)F-fluorodeoxyglucose (FDG) is increasingly used in the diagnostic management of colorectal cancer patients. It provides a highly sensitive and specific diagnosis which is entirely based upon alterations of the glucose metabolism found in malignant tissues. The information provided by FDG-PET is independent of the underlying structural characteristics of the lesions and, therefore, it is essentially complementary to the available structural imaging modalities such as CT, MRI and (endoscopic) ultrasound. Several studies have now been performed on the use of FDG-PET in colorectal adenocarcinoma for primary pre-operative staging, for diagnosis and (re)staging of recurrent disease, for localization and staging of occult recurrent disease, and for the assessment of the metabolic effects of chemotherapy and radiotherapy. This chapter aims to clarify some fundamental issues of both detection device and radiotracer, the proven indications for FDG-PET, the strength and limitations of the technique, and how its implementation would affect patient management.
Abstract: AIMS: This prospective study was designed to determine the utility of 18F-labelled deoxyglucose (FDG) in positron emission tomography (PET) (FDG-PET) for assessing the response to neoadjuvant chemoradiation therapy (CRT) in locally advanced oesophageal tumours. PATIENTS AND METHODS: Thirty-six patients with locally advanced oesophageal cancer (clinical T4 stage) without organ metastases, underwent FDG-PET before and 1 month after CRT. Patients were classified as major responders by serial FDG-PET when the post-CRT PET demonstrated a strong reduction of FDG uptake at the primary tumour site (>80% reduction of tumour-to-liver uptake ratio) without any abnormal FDG uptake elsewhere in the body. PET response was compared with histology obtained during post-induction transthoracic oesophagectomy. RESULTS: A strong correlation was found between the extent of lymph node (LN) involvement as shown by the pre-CRT PET and the major response rate (P = 0.001): such response occurred in nine of 11 N0M0 patients (82%), in three of nine N(1-2)M0 patients (33%) and in two of 16 patients (13%) with distant lymphatic spread. Such a correlation was not found for computed tomography or endoscopic ultrasonography. The sensitivity of serial FDG-PET for a major CRT response was 10 of 14 (71%), its specificity 18 of 22 (82%). The concordance between the response assessment by PET and histopathology was 78%. The median survival time after CRT of PET major responders compared with PET non-major responders was 16.3 months and 6.4 months, respectively. The metabolic response as measured by serial FDG-PET is a stronger prognostic factor for overall survival (P = 0.002) than the extent of LN involvement seen on the pretreatment FDG-PET (P = 0.087). CONCLUSIONS: These data indicate that CRT response as assessed by serial FDG-PET is strongly correlated with pathological response and survival.
Abstract: This retrospective study was designed to assess the accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in diagnosing recurrence of gastric cancer. Thirty-three patients who had received surgical treatment for gastric cancer with curative intent and who had subsequently undergone FDG-PET for suspected recurrence were retrieved from the PET database. All patients were reviewed with full knowledge of prior conventional diagnostic work-up. Results were compared with a gold standard, consisting of histological confirmation or radiological and clinical follow-up. The gold standard established disease recurrence in 20/33 patients (prevalence 61%). Sensitivity and specificity of FDG-PET for the diagnosis of recurrence were 70% (14/20) and 69% (9/13), respectively. Positive and negative predictive values were 78% (14/18) and 60% (9/15), respectively. Of the six false-negative cases, all had intra-abdominal lesions (three had generalised abdominal metastases, one liver metastasis, one local recurrence and one ovarian metastasis). In the subgroup with previous signet cell differentiation of the primary tumour ( n=13, disease prevalence 62%), sensitivity was 62% (5/8) and specificity, 60% (3/5). Survival analysis for the entire patient group using Kaplan-Meier statistics yielded a longer survival in the PET-negative group (mean+/-SD, 21.9+/-19.0 months) than in the PET-positive group (mean+/-SD, 9.2+/-8.2 months) ( P=0.01). In the patient group with proven recurrence ( n=20), the mean survival for the PET-negative group was 18.5 (+/-12.5) months, as compared with 6.9 (+/-6.5) months for the PET-positive group ( P=0.05). Because of its poor sensitivity and low negative predictive value, FDG-PET is not suited for screening purposes in the follow-up of treated gastric cancer. However, FDG-PET appears to provide important additional information concerning the prognosis of recurrent gastric cancer.
Abstract: BACKGROUND AND PURPOSE: To evaluate (1) parotid function, (2) subjective xerostomia and (3) pattern of relapses after conformal parotid-sparing radiotherapy (RT) for head and neck cancer. (4) To study dose-response curves of parotid glands. MATERIAL AND METHODS: From September 1999 to November 2000, 39 head and neck cancer patients requiring bilateral neck RT were treated with a fairly simple conformal RT technique (three-field set-up+anterior lower neck field; two opposed oblique boost fields). The contralateral parotid was spared. Parotid function was assessed by salivary gland scintigraphies performed before, early (median 4 weeks) and late (median 28 weeks) after RT. Xerostomia was monitored by visual analogue scales (VAS) and LENT SOMA scores. Location of locoregional recurrences was studied in relation to the radiation fields. A dose-response curve of parotids was created using logistic regression. RESULTS: (1) Early after RT, on salivary gland scintigraphy, the mean loss of secretion function in the spared parotid was 67% and total in the non-spared. Late after RT, the mean loss remained 19% in the spared and total in the non-spared parotid. Normal excretion function was regained in 75% of the spared parotids. (2) Late after RT, 78% of patients had no, minimal or acceptable subjective xerostomia. (3) No recurrence was seen near the spared parotid (11/39 locoregional recurrences). (4) The dose-response curve of parotids showed that the mean parotid dose should preferentially be < or =20 Gy, to obtain a good chance (> or =70%) for preservation of its function on scintigraphy. CONCLUSIONS: An easy conformal parotid-sparing RT technique prevents moderate or severe subjective xerostomia in 78% of patients. In the spared parotids, nearly complete to complete recovery is obtained after 6-12 months.
Abstract: BACKGROUND: FDG-PET scan has generated in recent years an increasing interest in staging and assessment of response to treatment in cancer patients. METHODS: From the available literature and own data it appears that FDG-PET scan significantly improves detection of haematogenous and distant lymphatic metastasis in carcinoma of the oesophagus and gastro-oesophageal junction (GEJ). Especially diagnostic specificity of lymph node involvement is greatly improved with FDG-PET scan. FDG-PET scan also allows a highly sensitive diagnosis of recurrent disease through its capacity of whole-body staging. In assessing response of induction (chemo +/- radiotherapy) in locally advanced disease FDG-PET scan appears to be of high value in predicting response. RESULTS: Moreover, there seems to be a strong correlation between FDG-PET scan response and survival. CONCLUSIONS: It can be concluded that despite the cost, FDG-PET scan should have a place in the algorithm of initial staging, staging of recurrent disease and assessment of response to treatment in cancer of the oesophagus and GE junction.
Abstract: In whole-body PET, it is not unusual to shorten the study time by omitting the transmission scan and to ignore attenuation during reconstruction. If a transmission scan is available, many centers reconstruct the images with, but also without, attenuation correction. Although ignoring attenuation leads to an artifact in the reconstructed images, these images still provide valuable diagnostic information in oncologic applications. Several authors have reported that the attenuation artifact may actually increase the tumor-to-background ratio. In this study, we analyzed the causes of the artifact and proposed a new algorithm to reduce the adverse effects on visual image quality. METHODS: We analyzed the causes of the attenuation artifact mathematically and numerically, and we examined its effect on tumor-to-background ratio and on signal-to-noise ratio. In addition, we showed that the attenuation artifact may lead to loss of image detail in conventional maximum-likelihood expectation maximization (MLEM) reconstruction. A new maximum-likelihood algorithm allowing negative reconstruction values (NEG-ML) was derived to reduce this loss. RESULTS: The attenuation artifact consists of 2 components. The first component is the well-known scaling effect: The apparent activity is reduced because attenuation decreases the fraction of detected photons. The second component is a relatively smooth negative contribution that is added to attenuated regions surrounded by activity. The second component tends to increase the tumor-to-background ratio. However, a simulation experiment shows that this increase in signal may be entirely offset by an increase in noise. The negative contribution can interfere with the nonnegativity constraint of the MLEM algorithm, leading to loss of image detail in regions of high attenuation. The new NEG-ML algorithm avoids the problem by allowing negative pixel values. The algorithm is similar to MLEM in the suppression of the streak artifact but provides more anatomic information. In our department, it is in routine clinical use for reconstruction of PET whole-body images without attenuation correction. CONCLUSION: Ignoring attenuation may increase the tumor-to-background ratio, but this increase does not imply improved tumor detection. The NEG-ML algorithm reduces the adverse effect of the attenuation artifact on visual image quality.
Abstract: Parathyroid tumors can be divided in adenomas and carcinomas, usually detected by hypercalcemia. We report a case of parathyroid adenoma in a young man, who complained of a pressure in the left neck region. Physical examination revealed a firm mass in the neck, without lymphnodes. Although Ca (9.7 mg/dl), phosphorus (3.3 mg/dl) and intact-PTH (49 pg/ml) were normal, imaging techniques (computed tomography scan and sestamibi substraction scan) suggested that the mass could arise from the parathyroid gland. Histology and immune staining for chromogranin and parathyroid hormone confirmed the parathyroid nature of the mass. Histological criteria defined the lesion as an atypical parathyroid adenoma. We review the pathology, diagnosis and treatment of parathyroid adenomas in its non-secreting atypical form.
Abstract: OBJECTIVES: The aim of this study was to investigate the prognostic value of carbon-11-acetate (acetate) positron emission tomography (PET) after successful reperfusion of myocardial infarction (MI). BACKGROUND: Acetate PET allows the measurement of both myocardial flow and oxidative metabolism. The prognostic value of acetate measurements performed early (within 24 h) after Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 reperfused MI is unknown. METHODS: In 18 patients with TIMI flow grade 3 reperfusion of their first MI, a dynamic acetate study was performed within 24 h of the acute event. At five days, nitrogen-13-NH3 (NH3) and fluorine-18-labeled fluorodeoxyglucose (FDG) PET studies were performed. Infarct-related areas were classified as "PET viable" or "PET nonviable," as assessed with NH3 and FDG, according to previously established criteria. At five days and three months, radionuclide angiography was performed for evaluation of left ventricular (LV) function. RESULTS: In infarct-related regions, myocardial blood flow, FDG uptake and oxygen consumption were decreased, compared with remote regions. However, oxygen consumption values, as measured with acetate in both PET-viable and PET-nonviable areas, as assessed with NH3 and FDG, were not significantly different (p = NS). A significant linear correlation was observed between global LV ejection fraction at three months and oxidative metabolism in the infarct-related area (r = 0.8, p < 0.0001). Multivariate analysis revealed that oxidative metabolism measurements in reperfused myocardium was the only significant predictor for recovery of LV function at three months (p < 0.05). CONCLUSIONS: Measurement of oxidative metabolism early after TIMI flow grade 3 reperfusion of MI offers important prognostic value concerning LV function at follow-up.
Abstract: Salivary gland scintigraphy (SGS) is used to depict salivary gland dysfunction after radiotherapy (RT). The aim of this study was to investigate the utility of SGS combined with single photon emission computed tomography (SPECT). Twenty-one patients with a carcinoma of head and neck underwent SGS before and 1 month after RT. After injection of 370 MBq 99Tcm-pertechnetate, a biplanar dynamic acquisition (12 x 1 min) was started, followed by a SPECT acquisition during 4 min. Carbachol was then injected and a second dynamic study (16 x 1 min) was performed, again followed by a SPECT acquisition. The salivary excretion fraction (SEF) was calculated both from the geometric mean planar image for each parotid and from the SPECT data for each transverse plane through the parotids. The RT-induced changes in the SEF (dSEF) were correlated with the mean radiation dose calculated using tomography-based dosimetry. The mean radiation dose to the parotids was 44 Gy (range 4.4-68.1 Gy). The mean range of the variation in radiation dose to the transverse slices within the parotids of a patient was 24 Gy (range 6.2-51.9 Gy). Considering all transverse planes through the parotids in all patients, a linear correlation was found between the dSEF calculated using SGS-SPECT and the radiation dose (r=0.45, P=0.0001). Thirteen patients had a variation in radiation dose within the parotids of more than 20 Gy. In nine of these a significant intra-individual correlation between radiation dose and the dSEF of the transverse parotid slices was found (r range 0.55-0.97; P value range 0.037-0.0001). In conclusion, SGS-SPECT can be used for monitoring radiation-induced parotid gland dysfunction. It offers the unique possibility for the assessment of intra-individual dose-dysfunction curves in patients with large variations in the radiation dose within the parotids.
Abstract: The aim of the study was to evaluate the use of positron emission tomography with [18F]-fluorodeoxyglucose (FDG-PET) in patients with unexplained rising carcinoembryonic antigen (CEA) in the postoperative surveillance of colorectal cancer. 50 consecutive patients with elevated CEA levels and a completely normal (n=31) or equivocal (n=19) conventional diagnostic work-up (CDW) were retrospectively selected. All PET images were reviewed with full knowledge of the CDW. The gold standard consisted of histology, or clinical follow-up of more than 1 year. Recurrent disease was established in 56 lesions in 43 patients. On a patient-based analysis, the sensitivity of FDG-PET was 34/43 (79%), and the positive predictive value 34/38 (89%). In 14/50 patients (28%), the FDG-PET findings led to a surgical resection with curative intent. On a lesion-based analysis, FDG-PET detected 42/56 lesions (sensitivity: 75%), the positive predictive value was 79% (42/53). These results demonstrate that FDG-PET can have a clear impact on patient management in patients with an unexplained elevation in CEA levels.
Abstract: AIMS: In selected patients with colorectal liver metastases, hepatic resection offers an opportunity for cure, with a 25-38% 5-year survival rate. The aim of this prospective study was to evaluate whether patient selection could be improved with pre-operative whole-body 18-fluoro-2-deoxyglucose-positron emission tomography (FDG-PET) scan. METHODS: Ninety-one consecutive patients were considered to be eligible for liver resection after investigation with conventional diagnostic methods (CDM). In all these patients a whole-body PET scan with FDG was performed prior to surgery. Follow-up was complete with a mean of 23 months (2 weeks-92 months). All PET images were reviewed blinded to intraoperative and follow-up data. RESULTS: PET confirmed liver metastases in 90 (99%) patients, while it provided additional information in 10 (11%) patients, i.e., seven intra-abdominal, and three extra-abdominal. PET falsely upstaged six (6.6%) patients in whom malignancy was excluded by additional investigation, at the time of surgery, or during follow-up. PET falsely understaged seven (7.7%) patients with small intra-abdominal lesions. CONCLUSION: In patients with potentially curable colorectal liver metastases according to conventional diagnostic methods, whole-body FDG-PET can be considered as a complementary examination in order to further select patients for potentially curative liver resection, and to optimize therapeutic strategy.
Abstract: PURPOSE: A prospective study of preoperative tumor-node-metastasis staging of patients with esophageal cancer (EC) was designed to compare the accuracy of 18-F-fluoro-deoxy-D-glucose (FDG) positron emission tomography (PET) with conventional noninvasive modalities. PATIENTS AND METHODS: Seventy-four patients with carcinomas of the esophagus (n = 43) or gastroesophageal junction (n = 31) were studied. All patients underwent attenuation-corrected FDG-PET imaging, a spiral computed tomography (CT) scan, and an endoscopic ultrasound (EUS). RESULTS: FDG-PET demonstrated increased activity in the primary tumor in 70 of 74 patients (sensitivity: 95%). False-negative PET images were found in four patients with T1 lesions. Thirty-four patients (46%) had stage IV disease. FDG-PET had a higher accuracy for diagnosing stage IV disease compared with the combination of CT and EUS (82% v 64%, respectively; P: =.004). FDG-PET had additional diagnostic value in 16 (22%) of 74 patients by upstaging 11 (15%) and downstaging five (7%) patients. Thirty-nine (53%) of the 74 patients underwent a 2- or 3-field lymphadenectomy in conjunction with primary curative esophagectomy. In these patients, tumoral involvement was found in 21 local and 35 regional or distant lymph nodes (LN). For local LN, the sensitivity of FDG-PET was lower than EUS (33% v 81%, respectively; P: =.027), but the specificity may have been higher (89% v 67%, respectively; P: = not significant [NS]). For the assessment of regional and distant LN involvement, compared with the combined use of CT and EUS, FDG-PET had a higher specificity (90% v 98%, respectively; P: =. 025) and a similar sensitivity (46% v 43%, respectively; P: = NS). CONCLUSION: PET significantly improves the detection of stage IV disease in EC compared with the conventional staging modalities. PET improves diagnostic specificity for LN staging.
Abstract: OBJECTIVE: To assess the value of positron emission tomography with 18fluorodeoxyglucose (FDG-PET) for preoperative lymph node staging of patients with primary cancer of the esophagus and gastroesophageal junction. SUMMARY BACKGROUND DATA: FDG-PET appears to be a promising tool in the preoperative staging of cancer of the esophagus and gastroesophageal junction. Recent reports indicate a higher sensitivity and specificity for detection of stage IV disease and a higher specificity for diagnosis of lymph node involvement compared with the standard use of computed tomography and endoscopic ultrasound. METHODS: Forty-two patients entered the prospective study. All underwent attenuation-corrected FDG-PET imaging of the neck, thorax, and upper abdomen, a spiral computed tomography scan, and an endoscopic ultrasound. The gold standard consisted exclusively of the histology of sampled nodes obtained by extensive two-field or three-field lymphadenectomies (n = 39) or from guided biopsies of suspicious distant nodes indicated by imaging (n = 3). RESULTS: The FDG-PET scan had lower accuracy for the diagnosis of locoregional nodes (N1-2) than combined computed tomography and endoscopic ultrasound (48% vs. 69%) because of a significant lack of sensitivity (22% vs. 83%). The accuracy for distant nodal metastasis (M+Ly), however, was significantly higher for FDG-PET than the combined use of computed tomography and endoscopic ultrasound (86% vs. 62%). Sensitivity was not significantly different, but specificity was greater (90% vs. 69%). The FDG-PET scan correctly upstaged five patients (12%) from N1-2 stage to M+Ly stage. One patient was falsely downstaged by FDG-PET scanning. CONCLUSIONS: FDG-PET scanning improves the clinical staging of lymph node involvement based on the increased detection of distant nodal metastases and on the superior specificity compared with conventional imaging modalities.
Abstract: OBJECTIVE: To study the utility of whole-body positron emission tomography with (18)F-fluoro-deoxy-D -glucose (FDG-PET) for the evaluation of recurrence after curative resection of cancer of the esophagus or gastroesophageal junction. METHODS: Forty-one patients with a clinical or radiologic suspicion of recurrent disease underwent conventional diagnostic work-up, including a spiral computed tomographic scan, an endoscopic ultrasound, and a dedicated whole-body FDG-PET. PET lesions were classified as equivocal or suspicious recurrence. The conventional diagnostic work-up and PET findings were correlated with pathology or with radiologic and clinical follow-up. Equivocal lesions were classified as positive. RESULTS: Forty recurrences were found in 33 patients. The lesions were perianastomotic (n = 9), regional (n = 12), and at distant sites (n = 19). For the diagnosis of a perianastomotic recurrence, the sensitivity, specificity, and accuracy of FDG-PET were 100%, 57%, and 74%, versus 100%, 93%, and 96% for conventional diagnostic work-up, respectively (P = not significant). False-positive PET lesions were found in patients with a progressive anastomotic stenosis requiring repetitive endoscopic dilatation. For the diagnosis of regional and distant recurrences, the sensitivity, specificity, and accuracy of PET were 94%, 82%, and 87%, versus 81% (P = not significant), 82% (P = not significant), and 81% (P =.0771) for conventional diagnostic work-up. All false-positive PET lesions (n = 4) had been reported as equivocal. On a patient base, PET provided additional information in 11 of 41 (27%) patients. A major impact on diagnosis was found in 5 patients with equivocal or negative findings on complete diagnostic work-up in whom PET provided a true-positive diagnosis. In 5 other patients the diagnosis was staged upward from localized to extended recurrent disease, and in 1 patient with an equivocal complete diagnostic work-up, PET correctly excluded malignancy. CONCLUSION: FDG-PET allows a highly sensitive diagnosis and accurate whole-body staging of symptomatic recurrent esophageal cancer. Further studies in asymptomatic patients are needed to assess the potential benefit on survival.
Abstract: PURPOSE: To assess the additional value of the whole-body [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) scan as a staging modality complementing conventional diagnostic methods (CDM) in patients suspected of having recurrent colorectal adenocarcinoma. PATIENTS AND METHODS: In 103 patients, the discordances between FDG-PET and CDM results were identified and related to the final diagnosis obtained by histopathology or clinical follow-up (> 1 year). All FDG-PET studies were reviewed with full knowledge of the CDM findings. RESULTS: In a region-based analysis, discordances between CDM and FDG-PET findings were found in 40 of 412 regions (10%). In these, FDG-PET had additional diagnostic value in 14 of 16 locoregional, six of seven hepatic, seven of eight abdominal, and eight of nine extra-abdominal regions. In a patient-based analysis, CDM categorized a subgroup of 60 patients as having resectable recurrent disease limited to the liver (n = 37) or locoregional region (n = 23). In 13 of these patients, there were discordant FDG-PET findings, detecting additional tumor sites in nine patients and excluding disease in three patients and yielding an additional diagnostic value in 20% of the patients. A second subgroup consisted of 13 patients with inconclusive CDM findings (n = 5) or with elevated plasma carcinoembryonic antigen levels and an otherwise negative conventional work-up (n = 8). In these patients, FDG-PET results were correct in eight of nine discordances, yielding a positive additional diagnostic value in 62% of the patients. CONCLUSION: Whole-body FDG-PET can have a clear impact on the therapeutic management in the follow-up of patients with colorectal cancer.
Abstract: 5-HT2A receptors have been implicated in the pathophysiology of mood disorders and in the therapeutic effect of the so-called atypical antipsychotics. Recently, a new radioiodinated ligand with high affinity and selectivity for serotonin 5-HT2A receptors, 123iodinated 4-amino-N-1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl] 5-iodo-2-methoxybenzamide (123I-5-I-R91150), has been developed and has been shown to be suitable for single-photon emission tomography (SPET) imaging. In this study the influence of age and gender on the ligand binding was investigated in normal volunteers. One hundred and fifty MBq of 123I-5-I-R91150 was administered to 26 normal volunteers (13 females and 13 males) with an age range of 23-60 years. SPET imaging was performed with a triple-headed gamma camera. For semi-quantitative analysis, ratios of ligand binding in different regions of interest to the binding in the cerebellum were calculated. Mean ratios of 1.7 were obtained. No gender difference was demonstrated. 5-HT2A binding was shown to decline with age. Over an age range of 40 years a reduction in ligand binding of 42% +/- 7% was found. These results are in agreement w in vitro and positron emission tomography findings of a decline in 5-HT2A receptor binding with age. The findings confirm the suitability of 123I-5-I-R91150 for SPET imaging of 5-HT2A receptors, and highlight the necessity for age-matched controls in clinical studies.
Abstract: The uptake of iodine-123 alpha-methyl-l-tyrosine (IMT) in the primary tumours and metastatic lymph nodes of squamous cell carcinoma of the head and neck was examined with single-photon emission tomography (SPET). Eleven patients with biopsy-proven carcinomas were studied prior to any therapeutic action. The evaluation of cervical lymph node involvement was based on the findings of physical examination, computed tomography and magnetic resonance imaging, and in six patients on the histological data relating to tissue samples obtained by fine-needle lymph node aspiration or surgical intervention. SPET imaging was performed 10 min after the injection of 130-170 MBq IMT using a triple-head gamma camera equipped with medium-energy collimators. High-quality IMT SPET depicted the primary tumour in 10 of 11 patients (sensitivity: 91%). Tumours located in the larynx were visualized more clearly than those located in the mouth or oropharynx. The mean tumour-to-background ratio was 2.35 (range: 1.6-3.1) for laryngeal tumours and 1.67 (range: 1.2-2.2) for mouth and oropharyngeal tumours. Metastatic cervical lymph nodes were involved to various degrees in 8 of the 11 patients. Among these eight patients there were 16 sites, nine of which were detected by IMT SPET (sensitivity: 56%). If the IMT SPET findings were recorded per side of the neck, the sensitivity was 64%. Five of the seven missed metastatic lymph nodes were smaller than 15 mm. The mean tumour-to-background ratio of the scintigraphically visualized lymph nodes was 1.81+/-0.51 (range: 1.39-2.77). Asymmetric physiological submandibular salivary gland IMT uptake led to false-positive lymph node assessment in three patients. This study indicates the potential use of IMT SPET as a metabolic imaging modality in patients with head and neck squamous cell carcinoma.
Abstract: We retrospectively evaluated the frequency of renal scintigraphic abnormalities in children over 5 years admitted with a first symptomatic urinary tract infection (UTI). Among 261 children investigated, we found only 23 over 5 years having had technetium-99m-dimercaptosuccinic acid scintigraphy during the acute phase of a first UTI. Obvious scintigraphic abnormalities were detected in 14 children (15 kidneys): 12 kidneys showed focal cortical defects and 3 were small and deformed. Ultrasound was normal in 7 of the 15 kidneys with abnormal scintigraphy and in all the kidneys with normal scintigraphy. Among the 12 kidneys with focal cortical lesions, 8 kidneys returned to normal or improved considerably 2-12 months after initial work-up. In conclusion, in children over 5 years admitted with a first symptomatic UTI, the frequency of scintigraphic abnormalities is high and a strategy based only on ultrasound data would miss about 50% of the abnormal kidneys.
Abstract: Radiolabeled benzamides have recently been introduced for the detection of melanoma. We evaluated the potential clinical applicability of 123I-N-(2-diethylaminoethyl) 4-iodobenzamide ([123I]IDAB) for SPECT imaging of ocular melanoma. METHODS: Fourteen patients were studied, 10 with or suspected of malignant ocular melanoma and four with ocular naevi. All patients underwent SPECT imaging of the head and whole-body scintigraphy 4-5 hr after injection of 170 MBq [123I]IDAB. RESULTS: A definite tracer hyperfixation was observed in the pathological eye in 9 of 10 (90%) patients with ocular melanoma. The pathological-to-normal eye ratio averaged 1.46 (range 1.07-2.86). The melanoma nature of the scintigraphic lesions was confirmed after enucleation in eight cases and by clinical evolution in two. A false-negative scan was reported in a patient with a small and hypochromic lesion. In patients with ocular naevi, no false-positive scintigrams were documented. CONCLUSION: Iodine-123-IDAB scintigraphy may contribute significantly to decide about enucleation in cases where some doubt persists with conventional techniques.
Abstract: Scintigraphy with 1123-N-(2-Diethyl aminoethyl) 4-Iodobenzamide (I123-IDAB), a radiolabeled benzamide, has recently been introduced to visualize sigma receptors in vivo. In this study we evaluated the potential clinical applicability of I123-IDAB scintigraphy in patients with melanoma and in patients with non-small cell lung carcinoma (NSCLC); tumors in which sigma receptors are expressed. Twenty-six patients with a history of malignant melanoma and 8 patients with proven NSCLC were studied. Whole body scintigraphy was performed 4-5 hours after the injection of 170 MBq of I123-IDAB. All patients with ocular lesions and those with NSCLC underwent SPECT imaging of the head or thorax, respectively. For other patients additional spot- and or SPECT scans of suspected regions were acquired if necessary. Three patients with a history of malignant melanoma were considered to be in complete remission. None presented abnormalities on the I123-IDAB scintigraphy. In 20 of the 23 patients (87%) with proven melanoma, lesions were identified on the I123-IDAB scintigraphy. On a lesion site basis the sensitivity averaged 64% (43/67) Lesions located in the liver and those originating from an amelanotic melanoma could not be detected, while a sensitivity of 89% was observed for ocular sites when SPECT was used. In patients with NSCLC all primary lesions showed an increased uptake of tracer, but only 4 out of 18 (22%) mediastinal lymph nodes that were suspected radiologically. I123-IDAB scintigraphy can be used to visualize melanoma and NSCLC lesions in vivo. In malignant melanoma this may be useful to confirm the melanoma nature of lesions that are not easily accessible to biopsy. Differences in sensitivity between the various sites however must be kept in mind when interpreting the I123-IDAB scintigraphy. In patients with NSCLC the value of I123-IDAB SPECT is at least questionable.
Abstract: BACKGROUND: The presence of bone-seeking radiopharmaceutical uptake in extraskeletal tissues of the lower or upper extremities may indirectly reflect the presence of active inflammatory lesions in patients in whom systemic disease is suspected. MATERIALS AND METHODS: The authors present the case of a 26-year-old woman who had mixed signs of scleroderma and cosinophilic fasciitis, in whom misleading findings on planar bone scintigraphy suggested diffuse muscular tracer uptake in the lower extremities. RESULTS: However, using additional SPECT imaging of the pelvis and thighs, it was shown that the soft tissue radioactivity was clearly restricted to the fascia overlying the muscles. The fascial localization of the inflammation was confirmed by biopsy. CONCLUSION: SPECT imaging was proven useful in indicating the exact localization of an active inflammatory process in the muscle fascia.
Abstract: A number of authors have indicated a more sensitive detection of renal cortical defects using single photon emission tomography (SPET) compared with planar imaging when performing 99Tcm-dimer-captosuccinic acid (99Tcm-DMSA) renal scintigraphy. The place of SPET in the evaluation of kidneys in adults suspected of acute pyelonephritis (APN) remains controversial, however. The aim of this study was to address the role of SPET in adult patients suspected of having APN. Planar and SPET 99Tcm-DMSA renal imaging was performed in 53 patients. The data sets were separated and presented in random order to three independent observers. The kidneys were divided into three segments, which were classified as normal, definitely abnormal or equivocal. Ir. a second step, the number of lesions (definite or equivocal) on planar and SPET imaging were counted. The overall concordance between the planar and SPET imaging scores was 90.9, 89.9 and 87.7% for the three observers, respectively. Inter-observer discordance was recorded in a small percentage of both planar and SPET images. The number of lesions, based on the average of the three observers, was 22 for planar and 25 for SPET imaging. Obvious differences between observers were noted. The planar images were more often interpreted as equivocal by the least experienced observer. The more experienced observers gained limited additional information using SPET routinely. Most equivocal lesions on the planar scintigrams were observed in the lower segment. For SPET, no such distribution was noted. High-quality 99Tcm-DMSA images allow the detection of the same number of lesions as SPET in adults suspected of APN.
Abstract: Left ventricular ejection fraction (LVEF) can be derived from gated single-photon emission tomographic (SPET) myocardial perfusion studies using either manual or edge detection techniques. In the presence of severe perfusion defects, however, difficulties may be encountered. In this article a method based on the assumption that the average position of the myocardial wall can be localized by means of statistical analysis of the distribution count density, and not on edge detection, is used to measure LVEF. SPET myocardial perfusion images, gated in eight time bins, were recorded in 50 patients 60 min after the injection of 925 MBq technetium-99m tetrofosmin. Masking of non-myocardial structures and thresholding resulted in images in which only myocardial walls had significant non-zero values. The distance of the wall relative to the centre of the cavity was calculated in the three-dimentional space as the first moment of the count rate distribution along radii originating in the centre of the cavity. LVEF was calculated using, for each time bin, the sum of the cube of all distances as an estimate of the cavity volume. The method required minimal operator interventions and was successful in all patients, including those with severe perfusion defects. Intraobserver and interobserver variability was excellent, with regression coefficients of 0.97 and standard deviations of 4.5% and 4.7%, respectively. For 30 patients, the measurements were validated against planar equilibrium radionuclide angiography (ERNA) that was obtained within an interval of 1 week. LVEF ranged from 12% to 88%. Agreement between the two methods was excellent (LVEFERNA=1.05+0.92 LVEFGSPET, r=0.93, P=0.023, SEE=7.06). The Bland-Altman analysis did not show any apparent trend in the differences between ERNA and gated SPET over a wide range of ejection fractions. The standard deviation of the differences was 3. 1%. In addition no relationship was found between the two methods and the severity of perfusion defects. In conclusion, accurate measurements of LVEF are obtained from gated SPET perfusion images using a method based on statistical analysis of the count rate density. This method did not deteriorate even in the presence of severe perfusion defects and could therefore be used in following patients after myocardial infarction.
Abstract: The aim of the study was to examine the ability to simultaneously assess left ventricular function and myocardial perfusion by using a single injection of technetium-99m sestamibi at rest and during submaximal exercise to identify high-risk patients with left main, proximal left anterior descending (LAD), or three-vessel coronary artery disease (CAD) after an uncomplicated acute myocardial infarction (AMI). Multiple studies have evaluated the separate value of the exercise ECG, myocardial perfusion scintigraphy, and radionuclide angiocardiography (RNA) for identifying patients with severe CAD. The availability of technetium-99m (Tc99m)-labeled myocardial imaging agents offers the opportunity to evaluate simultaneously ventricular function and myocardial perfusion during a single exercise session. Only limited data are available about the value of this combined technique in the workout of patients early after an uncomplicated AMI. Combined first-pass RNA and myocardial perfusion tomoscintigraphy (SPECT) at rest and during submaximal exercise were performed in 52 patients, less than six weeks after an uncomplicated AMI, with use of Tc99m sestamibi. Patients were classified in two subgroups according to the presence of left main, proximal LAD, or three-vessel CAD. Stepwise logistic regression analysis was used to determine the independent predictors of severe CAD. All patients underwent the exercise testing without any medical complication. On univariate analysis, the global left ventricular ejection fraction (LVEF), wall motion score, and myocardial perfusion score, both at rest and at submaximal exercise, were significantly associated with the presence of severe CAD. The response of LVEF to exercise, and the presence of exercise-induced wall motion or myocardial perfusion abnormalities, were not associated with the severity of CAD. On multivariant analysis only the wall motion score during exercise was an independent predictor for the presence of severe CAD (P < 0.001, r = 0.6). In analyzing patients with anterior AMI separately, LVEF at submaximal exercise was the most accurate predictive parameter. If a cutoff value of 40% was chosen, the LVEF at exercise had a sensitivity of 85% and a specificity of 78% for the detection of severe CAD. In patients with inferior AMI, neither LVEF nor wall motion or myocardial perfusion scores were useful for differentiating the two subgroups. In these patients the presence of an additional perfusion defect during exercise in one of the anterior wall segments yielded a sensitivity of 70% and a specificity of 75% for the presence of severe CAD. In conclusion: simultaneous evaluation of LV function and myocardial perfusion at submaximal exercise, using a single injection of Tc99m-sestamibi, is a safe and accurate technique for selecting patients with severe CAD after an uncomplicated AMI.
Abstract: Tetrofosmin is a new 99mTc-labeled myocardial perfusion imaging agent. Biodistribution studies suggest more favorable heart-to-adjacent organ biokinetics than for 99mTc-sestamibi after injection during exercise. The aim of this work was to determine intraindividually whether tetrofosmin is more suitable than sestamibi for pharmacological stress testing in a 1-day protocol. METHODS: Thirty subjects underwent two similar 1-day, rest and dipyridamole stress imaging protocols: one using tetrofosmin, the other using sestamibi. SPECT was performed 60 min after tracer administration. Myocardial images were analyzed both visually and quantitatively. RESULTS: Heart-to-liver activity ratios measured on the anterior SPECT projections were significantly higher for tetrofosmin than for sestamibi in the rest and stress studies. Heart-to-lung ratios were similar for both tracers. Significant linear correlations between tetrofosmin and sestamibi perfusion indices were found in normals and in patients with proven or suspected coronary artery disease. In segments showing abnormal uptake during stress, the perfusion indices were similar for tetrofosmin and sestamibi at rest and during stress. The degree of reversibility in these segments was also similar for both tracers. Finally, the extent, intensity and severity of perfusion defects were similar for both tracer studies. CONCLUSION: Tetrofosmin has a more optimal biodistribution than sestamibi when used in a 1-day, rest and dipyridamole stress myocardial SPECT imaging protocol. No significant difference in either the quality or diagnostic interpretation of the images could be demonstrated.
Abstract: Recently the presence of somatostatin receptors on human renal cell carcinomas has been demonstrated by autoradiographic techniques on surgically removed kidneys. In a prospective study we evaluated, by means of 111In-labelled octreotide scintigraphy, the in vivo tumour imaging in a group of patients with biopsy proven renal cell carcinomas at different tumour stages. Seven patients were studied. In three of them (43%) pathological tracer accumulation was demonstrated. In these patients 20 out of 23 known tumour localizations were clearly visualized. Tracer uptake could be inhibited by prior administration of cold octreotide. We conclude that 111In-octreotide scintigraphy can be used to demonstrate, in vivo, metastatic renal cell carcinoma.
Abstract: Stable intrathyroidal iodine pool (ITI) is known to affect both diagnosis and treatment of hyperthyroidism. Very few laboratories have facilities to measure ITI. In our department x-ray fluorescence was routinely used for more than 15 years. We report here that it is possible to predict the ITI by means of classic 131I turnover studies and at least distinguish hyperthyroid patients with a small ITI pool ("small pool" patients) from those with a large ITI. It could be shown from a retrospective study (selected hyperthyroid patients, n = 118) that (1) in our area the small pool patients represent the majority as opposed to the situation in the United States, (2) that there was a highly significant negative correlation (p < 0.001) between the PB 131I at 24 h and ITI, and (3) that the non-small pool patients were more resistant to treatment than the others. In a prospective study of 91 consecutive patients with a thyroid problem, it was be shown that in the euthyroid group no correlation could be found between ITI on the one hand and 131I uptake and PB 131I at 24 h or urinary iodine on the other. In the hyperthyroid patients a strong negative correlation was again found between ITI and PB 131I (p < 0.001), stronger than with 131I uptake p = 0.093). No correlation existed with urinary iodine. In a second prospective study of hyperthyroid patients (n = 56), it was confirmed that measuring the PB 131I could classify hyperthyroid patients into non-small pool and small pool subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract: Branhamella catarrhalis can be distinguished from Neisseria spp. by the presence of butyrate esterase. This enzyme can be rapidly detected when 4-methylumbelliferyl butyrate is used as the substrate. All B. catarrhalis strains tested gave a positive fluorescence reaction within 5 min, while Neisseria spp. remained negative, even after 18 h of incubation.
