Contralateral insular epileptogenic hub causing seizure relapse after opercular focal cortical dysplasia surgery and response to radiofrequency thermocoagulation: illustrative case.

BACKGROUND: The reevaluation and management of seizure relapse following resective surgery in magnetic resonance imaging (MRI)-negative pharmacoresistant epilepsy remains a significant challenge. OBSERVATIONS: A 25-year-old right-handed male with medically refractory epilepsy presented with nonlocalizing electroencephalography (EEG) and MRI. Stereo-EEG (SEEG) implantation based on semiology and positron emission tomography imaging revealed a left frontal opercular focus with rapid bilateral insular ictal synchrony. The initial epileptogenic zone was resected and pathologically proven to be type 2A focal cortical dysplasia (FCD). Seizure relapse after 9 months was eventually reinvestigated, and repeat SEEG revealed a secondary epileptogenic focus in the contralateral insula. A novel technique of volumetric stereotactic radiofrequency ablation (vRFA) was utilized for the right insular focus, following which, the patient remains seizure-free for 20 months. He suffered a transient bilateral opercular syndrome following the second intervention that eventually resolved. LESSONS: The authors present clinical evidence to suggest epileptogenic nodes distant from the primary focus as a mechanism for seizure relapse following FCD surgery and the importance of bilateral insular SEEG coverage. The authors also describe a novel technique of minimally invasive vRFA that allows ablation of a larger volume of cerebral cortex when compared to conventional bedside SEEG electrode thermocoagulation.

Role of dual time fluorodeoxyglucose (FDG) positron emission tomography-computed tomography in identifying co-existing inflammatory and malignant disease: Who holds it (FDG) longer?

18-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) is an integral part of imaging in the follow-up of head and neck malignancies. Very often distinguishing inflammatory/infective from malignant recurrence cannot be made confidently with standard uptake value (SUV) alone, as inflammatory lesions have shown to have a very high SUV, and in some cases both can co-exist. In such doubtful cases, dual time PET-CT (3-5 h delayed) is of paramount importance in confidently differentiating inflammatory/infective from a malignant cause.