Cerebral perfusion changes in patients with carotid artery stenosis after surgical revascularization

Assessment of cerebral perfusion and collateral circulation inpatients with carotid stenosis might have prognostic value foreffective blood flow restoration after carotid revascularization.To evaluate the changes of cerebral perfusion we studied 41patients with moderate and severe carotid stenosis before andafter surgical or endovascular treatment. Perfusion CT at thelevel of basal ganglia was performed in 17 patients with moderate(5069%) and 24 patients with severe (7099%) carotidstenosis for 3 times: before intervention (transluminal angioplastywith stenting or carotid endarterectomy), 3 to 7 days and 1 to3 months after treatment. Additionally, single CT perfusionstudy was done in 39 patients without carotid stenosis (controlgroup). We found that surgical recanalization of internal carotidartery may aid restoring cerebral blood flow characteristics in theMCA area to the levels similar to those in control group (namely,decrease of MTT and CBV and increase of CBF). However, inanterior and posterior watershed zones, which are known to bethe most vulnerable by chronic hypoperfusion, blood flow normalizationwas seen only in patients with complete circle ofWillis and with moderate carotid stenosis.Thus, prognostic factorsfor inadequate blood flow restoration in patients withcarotid artery stenosis after revascularization include severestenosis (70%) and incomplete circle of Willis.