Abstract
Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). But little is known about the change in intraoperative cerebral hemodynamics and its effect on postoperative neurological status, including symptomatic cerebral hyperperfusion. To address this issue, we applied a novel infrared imaging system (IRIS-V infrared imaging system) for intraoperative monitoring of surface hemodynamics in 2 patients with moyamoya disease. We investigated the correlation between clinical, radiological findings, and changes of the gradation value in infrared imaging using imaging software. The camera showed apparent revascularization during surgery in both cases. In case 1, a 36-year-old male who presented with transient ischemic attack (TIA) underwent superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis with pial synangiosis. His cerebrovascular reactivity was significantly compromised as shown by preoperative IMP-SPECT. Intraoperative infrared imaging disclosed an increase in brain surface temperature due to increase in blood flow around the anastomosis. The gradation value gradually increased after recanalization of bypass during several minutes. Postoperative IMP-SPECT showed a focal increase in CBF around the site of anastomosis 1 day after surgery. Beginning on the next day, he suffered fluctuated aphasia, numbness and fine movement disturbance on his right hand for 7 days. Intensive blood pressure control relieved his symptoms, and he was discharged without neurological deficit. The anatomical location and the temporal profile of hyperperfusion accorded with the neurological deficits.
In case 2, a 29-year-old female who presented with TIA had already undergone surgical revascularization on the symptomatic right side. Then she underwent left STA-MCA anastomosis on the asymptomatic side with decreased cerebrovascular reserve capacity. Intraoperative infrared imaging disclosed no significant increase in brain surface color around the site of anastomosis except for the apparent revascularization through STA-MCA bypass. The gradation value did change significantly before or after recanalization of bypass. Postoperative IMP-SPECT showed a mild increase in CBF on the entire MCA territory without focal intense accumulation. Her postoperative course was uneventful, and she was discharged without neurological deterioration.
Characteristic patterns of the intraoperative cerebral hemodynamics as delineated by IRIS-V may be the optimal predictor for postoperative transient symptomatic hyperperfusion after direct bypass in patients with moyamoya disease.
