摘要目的 用灌注CT成像(CTP)结合CO2吸入试验评价单侧大脑中动脉(MCA)狭窄患者MCA狭窄程度与脑血管储备力(CVR)的相关性.方法31例单侧MCA狭窄患者,CO2吸入试验前后行CTP检查.在基底节区、放射冠区及半卵圆中心层面选择感兴趣区,层厚8 mm,测量感兴趣区脑血流量,取各感兴趣区的脑血流量平均值.计算双侧MCA区CVR,测量MCA狭窄率,并按狭窄程度分为中度狭窄组和重度狭窄组,对MCA狭窄率与患侧CVR进行相关性分析.结果 31例患者患侧MCA分布区CO2吸人后脑血流量17例升高、2例无变化、12例降低.31例中有16例(51.6％)患者CVR下降,重度狭窄组中CVR下降患者的比例(13/19)高于中度狭窄组(3/12),P=0.029.MCA狭窄率与CVR存在等级相关(r=0.423,P=0.018).结论 单侧MCA狭窄患者中存在部分CVR下降,MCA狭窄率与其CVR具有等级正相关.

abstractsObjective To investigate the correlation between the unilateral middle cerebral artery (MCA)stenosis ratio and cerebrovascular reserve(CVR) using computed tomography perfusion (CTP) and CO2 inhalation test in patients with unilateral middle cerebral artery stenosis.Methods CTP were performed in 31 patients who were diagnosed as unilateral middle cerebral stenosis before and after CO2 inhalation.The basal ganglia and radial dimension were selected as interested regions (thickness 8 mm).The value of cerebral blood flow (CBF) was measured and the mean CBF values of all interested regions in each MCA territory were harvested separately.Then the CVR of each MCA territory was calculated according to the following formula:CVR =(CBF after CO2 inhalation test-CBF before CO2 inhalation test)/ CBF before CO2 inhalation test × 100％.Patients were divided into two groups:the severe stenosis group and the moderate stenosis group.The association between the MCA stenosis ratio and the CVR values was investigated.Results In 31 patients,different changes of CBF were found in affected MCA territory after CO2 inhalation.CBF increased in 17 cases,unchanged in 2 cases and decreased in 12 cases.A decreased CVR was detected in 51.6％ of the patients(16/31) and more likely found in the severe stenosis group (13/19) than that in the moderate stenosis group(3/12,P =0.029).The degree of stenosis in MCA was also significantly correlated with the changes of CVR(r =0.423,P =0.018).Conclusions CVR is decreased in some patients with unilateral MCA stenosis and significantly correlates with the severity of stenosis in MCA.