Hippocampal sclerosis is characterised by neuronal cell loss and gliosis in CA1, CA3, and dentate hilus subfields of the hippocampus, and can be reliably identified with MRI. The hippocampus is best visualised by acquiring thin slices (1–3 mm) orthogonal to its long axis. The primary MRI features of HS are hippocampal atrophy, demonstrated with coronal T1 weighted images, and increased signal intensity within the hippocampus on T2 weighted images . Additionally, decreased T1 weighted signal intensity and disruption of the internal structure of the hippocampus may be present. Other MRI abnormalities associated with hippocampal damage include atrophy of temporal lobe white matter and cortex, dilatation of the temporal horn, and a blurring of the grey-white border in the temporal neocortex. Atrophy of the amygdala and entorhinal cortex variably accompany hippocampal damage but may also occur in patients with TLE and normal hippocampi. FLAIR images provide an increased contrast between grey and white matter and facilitate differentiation of the amygdala from the hippocampus.


http://yassermetwally.wordpress.com/epilepsy-and-seizure-disorders/neuroimaging-of-seizure-disorders/