Epileptogenic zones can be localized by F-18 fluorodeoxyglucose positron emission tomography (FDG PET) and ictal single-photon emission computed tomography(SPECT). In medial temporal lobe epilepsy, the diagnostic sensitivity of FDG PET or ictal SPECT is excellent, however, the sensitivity of MRI is so high that the incremental sensitivity by FDG PET or ictal SPECT has yet to be proven. When MRI findings are ambiguous or normal, or discordant with those of ictal EEG, FDG PET and ictal SPECT are helpful for localization without the need for invasive ictal EEG. In neocortical epilepsy, the sensitivities of FDG PET or ictal SPECT are fair. However, because almost a half of the patients are normal on MRI, FDG PET and ictal SPECT are helpful for localization or at least for lateralization in these non-lesional epilepsies in order to guide the subdural insertion of electrodes. Interpretation of FDG PET has been recently advanced by voxel-based analysis and automatic volume of interest analysis based on a population template. Both analytical methods confirmed the performance of previous visual interpretation results. Ictal SPECT was analyzed using subtraction methods(coregistered to MRI) and voxel-based analysis. Rapidity of injection of tracers, HMPAO versus ECD, and repeated ictal SPECT, which remain the technical issues of ictal SPECT, are detailed.
Epilepsy/*radionuclide imaging ; Fludeoxyglucose F 18/diagnostic use ; Human ; Radiopharmaceuticals/diagnostic use ; *Tomography, Emission-Computed ; *Tomography, Emission-Computed, Single-Photon

BACKGROUND/AIMS: [18F]FDG-PET is a functional imaging modality reflecting cellular glucose metabolism. In most malignant cells, accumulation and trapping of [18F]FDG allows the visualization of increased uptake compared with normal cells. The aim of this study was to assess the value of PET in differentiating benign from malignant hepatic lesions and to determine in which types of hepatic tumors PET can help evaluate stage, monitor response to therapy, and detect recurrence. METHODS: Eighty patients with liver lesions were enrolled (hepatocellular carcinoma 34, cholangiocarcinoma 8, metastatic liver cancer 25, hemangioma 6, liver abscess 7). Liver metastases were 22 adenocarcinoma, 2 lymphoma, 2 squamous cell carcinoma. The PET images of these patients were analyzed. SUV and lesion-to-normal liver background SUV ratio were obtained and compared among the disease groups. RESULTS: All liver metastases and all cholangiocarcinomas had increased uptake value, with SUV ratios greater than 2. Hepatocellular carcinoma had SUV ratios greater than 2 in 20 of 34 patients (59%). All hemangiomas had poor uptake, a SUV ratio of less than 2. All liver abscesses showed definite uptake. CONCLUSIONS: The PET technique using FDG static imaging was useful in differentiating malignant from benign lesions of the liver in limited situations. Limitations included false negative results in some patients with hepatocellular carcinoma. Liver abscesses raised problems in differential diagnosis from malignant liver tumors. The findings of this study suggest that the PET technique might be applied in tumor staging and the detection of recurrence, as well as monitoring responses to therapy for all adenocarcinomas and some hepatocelluar carcinomas.
Adult ; Aged ; Diagnosis, Differential ; English Abstract ; Female ; Fludeoxyglucose F 18/diagnostic use ; Human ; Liver Diseases/*radionuclide imaging ; Liver Neoplasms/radionuclide imaging ; Male ; Middle Aged ; Radiopharmaceuticals/diagnostic use ; *Tomography, Emission-Computed

OBJECTIVE: To determine the accuracy of CT and positron emission tomography (PET) in the diagnosis of recurrent uterine cervical cancer. MATERIALS AND METHODS: Imaging findings of CT and PET in 36 patients (mean age, 53 years) in whom recurrent uterine cervical cancer was suspected were analyzed retrospectively. Between October 1997 and May 1998, they had undergone surgery and/or radiation therapy. Tumor recurrence was confirmed by pathologic examination or follow-up studies. RESULTS: In detecting recurrent uterine cervical cancer, the sensitivity, specificity, and accuracy of CT were 77.8%, 83.3%, and 80.5%, respectively, while for PET, the corresponding figures were 100%, 94.4%, and 97.2%. The Chisquare test revealed no significant difference in specificity (p = .2888), but significant differences in sensitivity (p = .0339) and accuracy (p = .0244). CONCLUSION: PET proved to be a reliable screening method for detecting recurrent uterine cervical cancer, but to determine the anatomical localization of recurrent tumors, and thus decide an adequate treatment plan, CT was eventually needed.
Adult ; Cervix Neoplasms/*radiography/*radionuclide imaging ; Comparative Study ; Contrast Media ; Female ; Fludeoxyglucose F 18/diagnostic use ; Human ; Middle Age ; Neoplasm Recurrence, Local/*radiography/*radionuclide imaging ; Radiopharmaceuticals/diagnostic use ; Sensitivity and Specificity ; *Tomography, Emission-Computed ; *Tomography, X-Ray Computed

The accurate staging of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) is an important aspect of treatment. In this study, the authors undertook to prospectively evaluate the clinical value of 2- (fluorine-18) fluoro-2-deoxy-D-glucose position emission tomography (FDG-PET) for the staging of malignant lymphoma as compared with computed tomography and 67Ga scan. Thirty consecutive cases with biopsy-proven lymphoma (4 HD, 26 NHL) were examined by FDG-PET for the initial staging and the restaging work-up between September 2000 and April 2001. The FDG-PET and conventional study, including a CT of the neck, chest, abdomen, and of the pelvis, a bone scan, a 67Ga scan, and a bone marrow study were undertaken to investigate nodal/extranodal manifestations and bone marrow infiltration. In terms of the detection of nodal lymphoma manifestation, the sensitivities and specificities of the PET, CT, and 67Ga scan were determined to be 93.3%, 98.9%, and 25.8%, and 100%, 99.1%, and 99.8%, respectively. In terms of the detection of extranodal lymphoma manifestation, the sensitivities and specificities of the PET, CT, and 67Ga scan were 87.5%, 87.5%, and 37.5%, and 100%, 100%, and 100%, respectively. The FDG-PET proved to be very accurate for the staging of malignant lymphoma and superior to Ga-67 scan. Although the results of PET and CT were substantially comparable, both imaging studies were found to complement each other in some cases with respect to the evaluation of lymphomatous involvement.
Adult ; Aged ; Aged, 80 and over ; Bone and Bones/radionuclide imaging ; Comparative Study ; Female ; Fludeoxyglucose F 18/*diagnostic use ; Gallium Radioisotopes/*diagnostic use ; Human ; Lymph Nodes/pathology ; Lymphoma/*pathology/radiography/radionuclide imaging ; Male ; Middle Aged ; Neoplasm Staging ; Prospective Studies ; *Tomography, Emission-Computed ; *Tomography, X-Ray Computed