Deformation based morphometry (DBM) in temporal lobe epilepsy with and without mesial temporal sclerosis

Background: Patients suffering from non-lesional medial temporal lobe epilepsy can, based on the appearance of the hippocampus, be divided into 2 clinical sub-groups: TLE with mesial temporal sclerosis as defined by MRI (TLE-mts), and those with normal appearing MRI on visual inspection (TLE-no). Structural MRI studies have consistently demonstrated global volumetric changes in TLE-mts. Structural changes in TLE-no are more subtle and have mainly been demonstrated using ROI methods of the mesial temporal structures. Deformation based morphometry (DBM) non-linearly transforms brain images to a standard template and maximizes the alignment of the anatomies between the individual brain and the template. The anatomical differences then lie in the deformation fields that are required to transform the subjects’ brain. The aim of this study was to identify structural shape changes using DBM in both TLE-mts and TLE-no.