Abstracts

Rationale: Intraoperative intrinsic optical imaging technique is important method to detect the precise functional distribution in the sensory cortex. We applied this method to epilepsy surgery for patients with sensori-motor epileptic focus. Methods: We used intrinsic optical imaging for three patients with intractable epilepsy who had epileptic focus in and around the sensory cortex. MRI revealed a cortical dysplasia in one patient, brain tumor in one patient, and normal finding in one patient. Optical recording was performed following cortical recording of SSEPs. The cortical surface was illuminated with Xenon light, and the reflected light, which passed through a 605 nm bandpass filter, was detected by optical imaging system. Individual electrical stimulation of thumb, little finger and palm induced changes in the reflected light intensities. For the purpose of visualizing the intrinsic optical responses, we constructed maps on the sensory strip. Results: 1) In all three cases, we can construct accurate functional maps on the sensory strip. This information has high spatial resolution and makes it possible to determine the resection border. 2) We can avoid resection of the finger cortex in one patient. In two patients we performed multiple subpial transection in the finger cortex. All three patients can avoid permanent neurological deficits. 3) Seizure-free outcome was obtained in two patients with MRI-visible lesion. Significant improvement was achieved in one patient with normal MRI. Conclusions: Intraoperative intrinsic optical imaging technique is a useful monitoring measure to detect the functional distribution in the sensory cortex, therefore, it is important clinical tool for avoiding neurological deficit in epileptic surgery.