Computed tomographic evaluation of corpus callosum agenesis and associated malformations.

Agenesis of the corpus callosum is not an uncommon congenital malformation in neurologically symptomatic children. The computed tomographic scan characteristics of uncomplicated agenesis of the corpus callosum include: (a) widely separated parallel or nonconverging lateral ventricles; (b) "Bat wing" or "bullhorn" appearance of the frontal horns; (c) High-riding third ventricle which may be enlarged and have a tear-drop or rhomboid appearance; and (d) Selective dilatation of the occipital horns occurs frequently. Associated malformations identifiable by computed tomographic scan include Dandy-Walker cysts, interhemispheric cysts, porencephaly, Arnold-Chiari II malformations, and skull deformities.