缺血性脑血管病的脑灌注MR与脑血管造影的对照研究

摘要

Objective To evaluate the value of perfusion MR imaging and angiographic evidence of collateral circulation in symptomatic patients with ischemic cerebrovascular diseases (ICVD).Methods Cerebral angiography and perfusion MR were performed in 16 patients with symptoms of ICVD. Qualitative perfusion maps were calculated for regional cerebral blood volume (rCBV) and mean transit time (MTT). Results A total of 27 lesions were seen on the perfusion MR maps (6 infarcts and 21 ischemic lesions) and most of them (26/27) showed a prolonged MTT. MTT is sensitive to the presence of ischemic lesions, but not sufficient in distinguishing infarct from ischemia. All of the infarcts showed a decreased rCBV, while most of the ischemic lesions showed a normal or increased rCBV. When collateral circulation was identified on angiography, most ischemic lesions were not infarcts and had a normal or increased rCBV. The absence of angiographically identifiable cerebral collaterals may not always result in an infarct; 50% had decreased rCBV. Despite the absence of angiographic collaterals, the other half had normal or increased rCBV. Conclusion Cerebral angiographic evidence of collateral circulation is important in identifying a favorable outcome in patients with ICVD. However, a lesion with a normal or increased rCBV suggests a sufficient collateral circulation even without angiographic collaterals. Perfusion images may be a potentially useful adjunctive tool in the prediction of the outcome of ICVD, particularly where no apparent collateral macrocirculation is seen on CA.%目的评价脑灌注MR和血管造影在判断缺血性脑血管病病变性质中的价值.方法本组包括16例具有缺血性脑血管病症状的病人,均进行了脑灌注MR扫描和脑血管造影造影检查.脑灌注MR包括局部脑血容量图(rCBV)和平均通过时间图(MTT).结果脑灌注MR扫描发现27个缺血病灶,其中6个为脑梗死,21个为缺血性病灶.绝大部分病灶(26/27)表现为MTT延长,MTT 图对是否存在缺血灶十分敏感, 但很难区分脑缺血和脑梗死.梗死灶全部表现为rCBV降低,而大部分缺血病灶表现为正常或稍高的rCBV.当脑血管造影证实存在侧枝循环时,大部分病灶表现为缺血改变而没有脑梗死, 脑灌注MR表现为正常或稍高的rCBV.脑血管造影未能证实侧枝循环时,51.7%的病灶为缺血灶, 50%表现为rCBV下降,另50%为正常或增高的rCBV.结论血管造影证实存在侧枝循环是缺血性脑血管病预后性质较好的征象,但在血管造影无侧支循环时,正常或增高的rCBV可能提示存在着足够的侧支循环.脑灌注成像在评价缺血性脑血管病性质中是一种有效的辅助工具,特别是在脑血管造影未能证实侧枝循环的病人中.