Magnetic resonance imaging after corpus callosotomy

Abstract

Magnetic resonance imaging (MRI) can visualize the extent of corpus callosotomy performed for medically intractable epilepsy not amenable to focal surgery. Five patients underwent complete callosotomy and one an anterior callosotomy, aged 19 to 24 years, 21 to 53 months (prior to scanning). T₁ images showed complete absence of the callosal shadow in five cases and visualization of the genu and splenium in the sixth case. T₂-weighted pulse sequence spinecho MRI showed intense image throughout the region of the entire callosum in the two cases with the longest postoperative course. The two middle cases showed intense T₂ signal from the splenium, and the two latest showed no increase in T₂ signal. We believe the increase in T₂ signal in the transected callosum may represent an in vivo example of anisomorphic gliosis. T₁ images demonstrate the anatomic extent of transection, while T₂ images demonstrate the chemical and pathophysiologic sequence of transection. Thus, MRI is the imaging test of choice to evaluate callosotomy patients.