37 PROPELLER MRI of Hippocampal Sclerosis Figure 3. Zoomed PROPELLER images of right (a) and left (c) temporal lobe in patient 2 with right HS. The right temporal lobe has been magniﬁed (b) for the comparison with matched histopathological sections (d, e). NeuN immunhistochem- istry conﬁrmed neuronal loss and atrophy (d). The myelinated tissue in the intervening white matter strata (strata moleculare, lacunosum, and radiatum) is clearly seen on the LFB-stained section (e, red arrow) and is indicated by a red arrowhead in the unaffected, normal hippocampus (c). It is less conspicuous on the sclerotic side in this case (b, red arrow). The black arrow and arrowhead indicate the hilus on the sclerotic and normal side respectively. Epilepsia C ILAE the hilar area. Neuronal loss and gliosis was confirmed in these regions on histopathological sections (Figs. 2–5). Mossy fiber sprouting and dispersion of the dentate granule cell layer were not appreciable on PROPELLER images of the sclerotic side. DISCUSSION Hippocampal sclerosis has been identified reliably in vivo by MRI for more than 15 years, but routine scans (T1-weighted volume and T2-weighted scans) do not Figure 4. Zoomed PROPELLER image of right (a) and left (b) temporal lobe in patient 3 with left HS. The left temporal lobe has been magniﬁed (c) for comparison with corresponding histopathological sections (d, e). Only a small amount of hippocampal subﬁelds CA1-3 were available in the histopathological sections. The myelinated tissue in the strata moleculare, lacunosum, and radiatum is clearly seen on the LFB-stained section (e) and can also be appreciated on the section immunolabeled for NeuN (d). Arrows indicate the corresponding areas on the PROPELLER image of the sclerotic hippocampus (c) and histopathological sections (d, e). Epilepsia C ILAE Epilepsia, 49(1):33–39, 2008 doi: 10.1111/j.1528-1167.2007.01277.x