磁共振灌注成像评估动脉瘤性蛛网膜下腔出血后脑血管痉挛的临床研究

Evaluation of cerebral vasospasm after aneurysmal subarachnoid hemorrhage based on perfusion-weighted magnetic resonance imaging

目的探讨磁共振灌注成像在动脉瘤性蛛网膜下腔出血后脑血管痉挛中的诊断价值,并探讨脑血流动力学与脑血管痉挛之间的关系。方法采用磁共振灌注加权成像和全脑血管造影的方法,对38例动脉瘤性蛛网膜下腔出血后(7±2)d的患者进行检查并动态观察。通过磁共振灌注成像检查采集大脑全动脉供血区,大脑中动脉供血区和基底节区所选感兴趣区的各项参数,包括rCBF、rCBV、MTT和TTP。通过分析这些参数,研究它们与脑血管痉挛程度的相关性。结果在38例患者中至少1条血管痉挛28例(轻度痉挛9例,中度痉挛10例,重度痉挛9例),无痉挛10例。按血管痉挛程度分成无痉挛组、轻度痉挛组、中度痉挛组、重度痉挛组。将rCBF、rCBV、TTP和MTT等参数纳入统计学分析,采用Spearman等级相关检验。在所有区域,伴随脑血管痉挛程度的加重,rCBV及rCBF值有所下降(P<0.05),在轻中度痉挛组,各区域rCBF及rCBV参数有增加和减少现象存在,重度痉挛组较对照组rCBF明显减少(P<0.05)。MTT及TTP呈明显线性增加趋势,痉挛组TTP分别较对照组明显延迟,有明显等级相关性(P<0.01)。结论进行磁共振灌注成像检查可以定量地提供脑组织血流灌注的信息。综合运用磁共振灌注成像和全脑血管造影技术对于研究脑血管痉挛的发展过程中血流灌注变化,有重要的临床意义。

Objective To investigate the disturbance of perfusion patterns attributable to cerebral vasospasm（CVS） after aneurysmal subarachnoid hemorrhage（SAH） by perfusion-weighted magnetic resonance imaging（PWI） and digital subtraction angiography（DSA）,and to study the correlation between cerebral hemodynamics and CVS in SAH patients.Methods PWI and DSA were performed on 38 SAH patients about 7±2 d after SAH.The patients were divided into a non-CVS group,a mild CVS group,a moderate CVS group,and a severe CVS group according to the CVS degrees.Parameters including relative cerebral blood flow（rCBF）,relative cerebral blood volume（rCBV）,mean transit time（MTT）,time to peak（TTP） in regions of interest（ROIs） of the anterior cerebral artery（ACA） perfusion area,the middle cerebral artery（MCA） perfusion area,and the basal ganglia area of each hemisphere were analyzed based on PWI.The correlation between the parameters and CVS was studied.Results Twenty-eight cases with vasospasm in at least one blood vessel were found in the patients,including 10 cases in the non-CVS group,9 in the mild CVS group,10 in the moderate CVS group,and 9 in the severe CVS group.The parameters rCBF,rCBV,TTP and MTT were statistically analyzed by Spearman rank correlation coefficient.In all ROIs,rCBV and rCBF decreased as CVS worsened（P0.05）.In the mild and moderate CVS groups,rCBF and rCBV decreased or increased in all ROIs.rCBF decreased significantly in the severe CVS group as compared with that in the control group（P0.05）.MTT and TTP in the CVS groups had a significant tendency of linear increase.TTP was significantly delayed in the CVS groups as compared with that in the control group,and had significant rank correlation（r=0.489 to 0.730,P0.01）.Conclusion PWI can provide quantitative information on the changes of cerebral hemodynamics.The combination of PWI and DSA has clinicopathologic significance when investigating the correlation between cerebral hemodynamics and CVS degrees in SAH patients.