Arteriovenous malformations of the corpus callosum--radioanatomic study and effectiveness of intranidus embolization.

Forty-three patients with arteriovenous malformations (AVMs) of the corpus callosum treated by embolization were reviewed. The following clinical and radioanatomic characteristics were found: 84% (36 patients) presented with intracranial hemorrhage, 43% (20 nidi) of the lesions were located in the posterior half of the corpus callosum, multiple nidi were more frequent (21%) than expected, 27 nidi (59%) were fed by branches of both the anterior and posterior cerebral arteries, AVMs mainly drained into the internal cerebral vein and/or interhemispheric superficial veins, and 19 (41%) had both draining pathways, 10 patients (23%) had impaired drainage through the straight sinus due to dysplasia. Staged embolization was performed in 245 feeders. Curative occlusion (more than 95%) was obtained in 17 patients (40%) and considerable occlusion (more than 75%) in 33 patients (77%). Large and giant, diffuse-type, and multifocal AVMs were difficult to completely embolize. Complications associated with embolization occurred in six patients, mostly during the first 5 years. Only two patients had a permanent deficit related to a complication. Overall morbidity and mortality were 7% and 2%, respectively. Nine patients were referred for stereotactic radiosurgery, three of whom were completely cured and five patients have not been assessed. Most AVMs in the corpus callosum are supplied by multi-axial feeders, so multi-target intranidus embolization is very important to prevent the development of other feeders secondary to the hemodynamic shift. Combined therapy using maximum embolization and subsequent radiosurgery may be the most effective method to treat AVMs in the corpus callosum.