Functional Imaging in Drug Refractory Epilepsy.

Introduction: Functional Imaging has a crucial role to play in the pre-surgical evaluation of drug refractory epilepsy (DRE) candidates when MRI is normal or equivocal, MRI is not concordant with electroclinical localisation, with multiple lesions and in patients with recurrent seizures post-surgery. A strong working hypothesis before going in for invasive monitoring is essential for good surgical outcomes. In this educational exhibit, we will demonstrate the utility of functional imaging and the imaging features for localization of the epileptogenic focus in the frequent pathological types of focal epilepsies.

Methods: A case-based review of clinical and functional imaging features emphasising on concordance between electroclinical, MRI, SISCOS, PET and MEG findings in each case and how they helped in localising the seizure onset zone prior to stereoencephalography (SEEG) and finally surgery will be discussed in detail. PET, SISCOS, Ictal PET will be discussed along with the utility of PET/MRI fusion and arterial spin labelling (ASL).

Results: The review will include A) Temporal lobe epilepsy (TLE)- neocortical focal cortical dysplasia (FCD)(Figure TLE), and FCD with mesial temporal sclerosis or tumor and B) Extratemporal epilepsy (ETE) including-Frontal/basifrontal (Figure BFE)/anterior cingulate, parietal and parieto-occipital epilepsies C) Ictal PET and D) Identification of red-flags for surgery- Rasmussen Encephalitis and autoimmune epilepsy (AIE) where additional work-up is required alongwith pattern recognition. The pathologies included will be FCD type I, FCD type II, FCD type III a & b including illustration of bottom of sulcus dysplasia (Figure BOSD), transmantle sign and cerebellar hamartoma (interesting findings on SISCOS and FDG PET). Special case scenarios with discordance between vEEG and MRI and anterior cingulate epilepsy will also be discussed.

Conclusions: In conclusion, we will provide a pictorial review of the clinical settings for the utility of functional imaging in hypothesis generation in the pre-surgical evaluation of DRE.

• Download figure
• Open in new tab
• Download powerpoint