Leptomeningeal collateral and cerebral hemodynamics in patients with ICA and MCA steno-occlusion

Objectives: The purpose of our study was to evaluate the correlation between fluid-attenuated inversion recovery (FLAIR) images of hyperintense vessel (HV), a representative of leptomeningeal vessels (LMVs), and cerebral vascular hemodynamic status in patients with steno-occlusive disease of the internal carotid artery (ICA) and middle cerebral artery (MCA). Methods: Sixty-eight patients with unilateral ICA or MCA stenosis or occlusion were enrolled. Correlations between hyperintense vessel (HV) on FLAIR images and hemodynamic status measured by quantitative single-photon emission computed tomography data were evaluated in four groups: affected (A) and non-affected (B) hemispheres in HV-positive patients, and affected (C) and non-affected (D) hemispheres in HV-negative patients. Results: The presence of HV was most frequently seen on affected hemispheres in patients with MCA and ICA occlusions. HV was significantly higher in the anterior communicating artery (AcomA) (-), posterior communicating artery (PcomA) (-) group than in other groups, which included either or both AcomA and PcomA (P=0.008). The presence of HV had a significant correlation with transdural anastomosis (P=0.046) and LMV (P=1.646x10(-9)). No significant difference was observed in resting regional cerebral blood flow among the four groups. Vascular reserve in group A was significantly less compared to other groups (P=0.021). Conclusions: HV is related to the hemisphere with severe ICA and MCA steno-occlusion when the circle of Willis is insufficient. The HV-positive hemisphere on the steno-occlusive side shows a lower vascular reserve than that in the contralateral hemisphere or HV-negative hemispheres.