Early Prenatal MR Imaging Diagnosis of Polymicrogyria

Multiplanar T2-weighted single-shot fast spin-echo sections from 24-week (A–C) and 34-week (D–G) gestational age.

A, Coronal section showing absent septum pellucidum and focal irregular wartlike profile of the cortical rim in the left hemisphere (white arrow).

B, Contiguous coronal section depicting a small hypointense subependymal nodule associated with a thin hypointense line extending toward the cortex (white arrowhead).

C, Axial section showing an unclear area of cortical-rim abnormal profile with apparent irregular infolding in the left hemisphere (curved white arrow).

D, Axial section depicting the absence of septum pellucidum.

E (left) and F (right), Axial contiguous sections from the same study showing in the left posterior frontal lobe a focal area of abnormal cortical-rim profile with some irregular infolding (black arrow).

G, Coronal section from the same study depicting in the left frontal lobe the same area of irregular and abnormally tight cortical gyri infolding (curved white arrow). Only the left half of the section has been reproduced, to eliminate the dynamic windowing problems related to the high signal intensity in the right side of the image, caused by the proximity to the surface coil.