carbon-11-methionine and Seizures

Dysembryoplastic neuroepithelial tumors (DNETs) are slow-growing epilepsy-associated tumors. Low or normal 11C-methionine (MET) PET uptake helps to differentiate DNETs from other low-grade gliomas. However, diverse MET-PET uptake in DNETs has been observed. The aim of this study is to measure the clinical significance and prognostic value of MET-PET in DNET management.. Retrospective review of 26 DNET patients was done. Clinical characteristics, radiologic findings, and visual and quantitative MET-PET results were analyzed. PET uptake was calculated as the tumor-to-homotopic mirror ratio (TNRm) and tumor-to-contralateral cortex ratio (TNRc). The clinical activity of the tumors at the time of PET was classified into active and quiescent groups. The surgical outcome was defined as a composite of 2 different aspects: tumor progression and/or clinical events such as seizure recurrence or tumor bleeding.. Twenty-seven MET-PET examinations (20 initial MET-PET and 7 MET-PET during follow-up) were included. Clinically active tumors at the time of PET presented significantly higher values of TNRm and TNRc than quiescent tumors. High MET-PET uptake by visual grading, TNRm ≥ 1.90, and TNRc ≥ 1.85 exhibited poor prognosis for event-free survival.. MET-PET uptake correlates well with the clinical behavior of DNETs at the time of PET examination. Moreover, High MET-PET uptake is closely related to seizure recurrence if tumors are not entirely resected. Efforts to achieve gross total resection should be made for DNETs with high MET-PET uptake.

Topics: Brain Neoplasms; Carbon Radioisotopes; Child; Glioma; Humans; Methionine; Positron-Emission Tomography; Seizures

Focal cortical dysplasia is one of the known neuronal migration disorders and has recently been recognized as a cause of intractable epilepsy. In this study, we assessed the 11C-methionine (MET) uptake in focal cortical dysplasia by PET, and then compared the results with that of 18F-fluoro-2-deoxy-D-glucose (FDG) PET and 99mTc-ethyl cysteinate dimer (ECD) SPECT.. Four patients (3 men, 1 woman; age range 16-68 yr) were examined by PET and SPECT for a presurgical examination of medically intractable seizures. In all 4 patients, 11C-MET PET was performed for 15 min, started 15 min after the administration of 511-662 MBq MET. In 3 of 4 patients, FDG PET was performed for 15 min, and started 20 min after the administration of 185-370 MBq FDG. In all 4 patients, the cerebral blood flow was also evaluated by 99mTc-ECD SPECT for 15 min after the administration of 600 MBq ECD.. In MET PET, all 4 lesions were visually recognized to have high MET uptake areas. The MET uptake of the lesions was 1.44 +/- 0.30 for the standardized uptake value (SUV) (ranging from 0.99-1.61). In FDG PET, 2 lesions were demonstrated to have low uptake areas (3.82 in SUV) while 1 had an ictal high uptake (4.74 in SUV). In ECD SPECT, 1 lesion demonstrated hypoperfusion and 1 ictal hyperperfusion while 2 showed no abnormalities. All 4 patients underwent a cortical resection and the microscopic examinations were consistent with those of focal cortical dysplasia but no evidence of a tumor was found.. MET PET is useful for identifying focal cortical dysplasia as a high uptake area.

Topics: Adolescent; Adult; Aged; Cerebral Cortex; Cerebrovascular Circulation; Cysteine; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Male; Methionine; Organotechnetium Compounds; Radiopharmaceuticals; Seizures; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon