GRAY-MATTER AND WHITE-MATTER PERFUSION IMAGING IN PATIENTS WITH SEVERE CAROTID-ARTERY LESIONS

PURPOSE: To determine, with dynamic susceptibility contrast-enhanced m agnetic resonance (MR) imaging, changes in gray matter and while matte r perfusion in patients with internal carotid artery (ICA) occlusions. MATERIALS AND METHODS: Regional cerebral blood volume (CBV), mean tra nsit time, arrival time (time for contrast material to arrive in the b rain), and peak time,(time to highest contrast material concentration in the brain) were determined in 44 patients and 33 control subjects. Patients were divided into three groups: patients with a unilateral IC A occlusion, patients with a unilateral ICA occlusion and a contralate ral severe stenosis (> 70%), and patients with bilateral ICA occlusion s. RESULTS: Compared with control subjects, patients with unilateral I CA occlusions had hemodynamic changes in the ipsilateral hemisphere: M ean transit time, arrival time, and peak time were increased in white and gray matter (P < .001), and regional CBV was significantly increas ed in white matter only (P < .01). Hemodynamic changes were more prono unced in patients with bilateral ICA occlusions: Compared with control subjects, mean transit time, arrival time, peak time, and regional CB V were increased in both white and gray matter in both hemispheres (P < .001). CONCLUSION: Dynamic susceptibility contrast-enhanced MR imagi ng can enable measurement of relative hemodynamic changes in patients with ICA occlusions, with the advantage that gray and white matter per fusion can be distinguished.