Intraoperative MRI with integrated functional neuronavigation-guided resection of supratentorial cavernous malformations in eloquent brain areas.

Between March 2009 and January 2010, 36 patients with 38 supratentorial cavernous malformations in eloquent brain areas underwent surgery with the aid of intraoperative MRI (iMRI), functional neuronavigation, and electrocorticography (ECoG). To optimize outcomes, the hemosiderin-stained tissue surrounding the lesion in addition to the cavernous malformation itself (lesion) was microsurgically removed, leaving behind only small areas adjacent to, or overlapping with, functional areas. According to the Zabramski classification, there were 13 type I lesions, which all underwent total resection. There were 25 type II or III lesions with a surrounding hypointense rim, and all of these lesions were completely removed; the surrounding hypointense rims were completely removed in 15 patients and partially removed in 10. No new neurologic disorders occurred postoperatively. Twenty patients had preoperative epileptic seizures, nine of whom were refractory to treatment. During follow-up, seizure outcome was assessed using the Engel classification, and 11 patients with non-refractory epilepsy had a class I outcome. Of the nine patients with refractory epilepsy, seven (77.8%) had a class I outcome, one (11.1%) had a class II outcome, and one (11.1%) had a class III outcome.