Comparison of Diagnostic Performance between Interictal F-18-FDG PET and Ictal Tc-99m-HMPAO SPECT in Occipital Lobe Epilepsy

Kim, Seok Ki; Lee, Dong Soo; Yeo, Jeong Seok; Lee, Sang Kun; Kim, Joo Yong; Jeong, Jae Min; Chung, June Key; Lee, Myung Chul

Abstract

PURPOSE: Interictal F-18-fluorodeoxyglucose (FDG) PET and ictal Tc-99m-HMPAO SPECT are found to be useful in localizing epileptogenic zones in neocortical lateral temporal or frontal lobe epilepsy. We investigated whether interictal F-18-FDG PET or ictal Tc-99m-HMPAO SPECT was useful to find epileptogenic zones in occipital lobe epilepsy (OLE).
MATERIALS AND METHODS
We reviewed patterns of hypometabolism in interictal F-18-FDG PET and of hyperperfusion in ictal Tc-99m-HMPAO SPECT in 17 OLE patients (mean age=27+/-6.8 year, M:F=10:7, injection time=30+/-17 sec). OLE was diagnosed based on invasive electroencephalography (EEG) study, surgery and post-surgical outcome (Engel class I in all for average 14 months).
RESULTS
Epileptogenic zones were correctly localized in 9 (60%) out of 15 patients by interictal F-18-FDG PET. Epiletogenic hemispheres were correctly lateralized in 14 patients (93%). By ictal Tc-99m-HMPAO SPECT, epileptogenic hemispheres were correctly lateralized in 13 patients (76%), but localization was possible only in 3 patients (18%). Among patients who showed no abnormality with MR imaging and no correct localization with ictal Tc-99m-HMPAO SPECT, interictal F-18-FDG PET was helpful in 2 patients.
CONCLUSION
: Ictal Tc-99m-HMPAO SPECT was helpful in lateralization but not in localization in OLE. Interictal F-18-FDG PET was helpful for localization of epileptogenic zones even in patients with ambiguous MR or ictal SPECT findings. Key KW: Occipital lobe epilepsy, Tc-99m-HMPAO, Ictal perfusion SPECT, F-18-FDG, PET, SPECT