Disorders of Cortical Formation: MR Imaging Features

Hemimegalencephaly. A and B, Coronal T2-weighted images show an enlarged left cerebral hemisphere, a dilated left lateral ventricle, and a thickened cerebral cortex. Courtesy of Dr R. Zimmerman, Philadelphia.

Focal cortical dysplasia. A and B, Axial and coronal T2-weighted images show focal cortical thickening in the right frontal lobe. Courtesy of Dr R. Zimmerman, Philadelphia.

Complete lissencephaly. Axial T2-weighted image shows complete absence of sulci with a thick cortex, a shallow Sylvian fissure, and a circumferential band of high signal intensity in the parietooccipital cortex.

Cobblestone lissencephaly. A and B, Axial and coronal T2-weighted images show an irregular nodular cortex with hypomyelination of the white matter.

WWS. A, Axial T2-weighted image shows a cobblestone cerebral cortex with hypomyelination of the white matter. B, Sagittal T1-weighted image shows hydrocephalus, an occipital encephalocele, a pontomedullary kink, and a small pons.

MEB syndrome. A, Axial T2-weighted image shows undersulcation of the frontal lobe, hypomyelination of the frontal white matter, and dilated lateral ventricles. B, Axial T2-weighted image shows multiple small cerebellar cysts, with a small pons and bilateral temporal arachnoid cysts.

PVH. A and B, Coronal T1-weighted images show a few small periventricular nodules, isointense to the gray matter, along the lateral ventricular wall.

Curvilinear SCH. Axial T2-weighted MR image shows curvilinear heterotopias in the right cerebral hemisphere that are associated with its decrease in size.

Mixed SCH. Axial T2-weighted MR image shows a large nodule adjacent to the lateral ventricle with a signal intensity similar to that of the gray matter and curvilinear convolutions in the superficial part.

PMG. Axial T2-weighted image shows microgyria with normal cortical thickness that is associated with the high signal intensity of the white matter.