FIG 4. Focal polymicrogyria in the left frontal lobe. Contiguous, 3-mm-thick, coronal FLAIR fast spin-echo sections (a–c) show a deep superior frontal sulcus with a slightly irregular contour and a normal signal intensity of the cortex (arrow). Planar surface-reconstructed view (d) generated from a 1.1-mm-thick, 3D, T1-weighted gradient-echo sequence confirms the distorted anatomy (arrow). Histopathologic sections show loss of neocortical architecture (MAP2 [e]) compared with that of adjacent six–layered cortex (nematoxylin–eosin straining [f]).