Postprocessing of MRIs Using FreeSurfer in Epilepsy Surgery Patients Provides an Excellent Imaging Marker of Hippocampal Sclerosis but Fails to Separate Subtypes

Objective. Histopathological examinations will diminish as minimally invasive epilepsy surgery increasingly replaces open surgery. The objective of this study was to test if visual and computer-aided quantitative analyses presurgical high-quality 3 Tesla MRIs complying with the International League Against Epilepsy (ILAE) Neuroimaging Task Force recommendations can inform on histopathological diagnosis. Methods. Ninety-two patients from Copenhagen Oslo University Hospitals fulfilled patient-, imaging-, inclusion criteria: 69 were diagnosed hippocampal sclerosis (HS) ILAE type 1 or 2, 23 had normal appearing hippocampi other histopathology than HS (no-HS). 52 healthy controls (HC) included. Image processing performed in FreeSurfer v.6.0 built-in cross-sectional subfield segmentation tool multimodal MRI input. Volume outputs used calculate volume asymmetry ratios (VARs) for whole hippocampus (WH) subfields. Results. significantly larger WH VARs compared no-HS HC, a sensitivity = 0.93 id="M2"> specificity 1.0 Visual assessment yielded id="M3"> 0.90 id="M4"> 0.96 CA1 CA4 number seizure-free not different 2 patients. Significance. are excellent at separating histopathologically pathology hippocampi. Using did allow subtypes.