Detection of epileptogenic focus with two new methods of processing of SPECT and PET cerebral images: PET-Analysis and PISCOM

Functional neuroimaging with positron emission tomography with ¹⁸F-fluorodeoxyglucose (PET-¹⁸F-FDG) and perfusion single photon emission computerized tomography (SPECT) are increasingly more essential for presurgically locating the epileptogenic focus. We present the case of an 18-year-old male with epileptic seizures refractory to antiepileptic treatment. Magnetic resonance (MR) showed dysplasia in the posterior right insular cortex. Subtraction of ictal SPECT co-registered to MR (SICOM) detected a focal increase of uptake in the left fronto-parietal cingulate and PET-FDG showed normal distribution of the radiotracer. The posterior right insula was resected with histopathological results of grade I ganglioglioma according to the World Health Organization classification. The patient made favourable post-surgical progress, and remains seizure-free after 5 years (Engel I). Retrospective analysis of this case with two new image processing methods (PET analysis and PET interictal subtracted ictal SPECT coregistered with MR [PISCOM]) correctly localized the epileptogenic focus in the posterior right insular cortex.