DCE-MRI对烟雾病手术前后微循环和血脑屏障变化的定量研究

Quantitative Study on Changes of Microcirculation and Blood-Brain Barrier in Patients with Moyamoya Disease Before and After Operation by DCE-MRI

目的:探讨磁共振动态对比增强(Dynamic Contrast-Enhanced MRI,DCE-MRI)在评价烟雾病术前侧支循环及微循环情况、血脑屏障破坏程度及术后微循环改善、血脑屏障恢复状况中的作用。方法:分析经数字减影血管造影(Digital Subtraction Angiography,DSA)和/或计算机断层血管成像(Computed Tomography Angiography,CTA)确诊的烟雾病患者20例进行常规MRI、T1增强扫描及DCE-MRI检查,选取基底节、放射冠层面,按照大脑前、中、后动脉及穿支动脉供血分布范围,分为22个脑实质分区,利用DSA对22个分区的侧支循环进行评分(0、1、2和3分);DCE-MRI分别计算相应分区血管容积交换常数(Volume Transfer Constant,K^(trans)),根据K^(trans)值大小进行评分(0、1、2和3分),对22个分区K^(trans)值、DSA评分行Kappa一致性检验(P<0.05差异有统计学意义);术前将病变显著侧大脑半球感兴趣区K^(trans)值同镜像侧脑实质区进行比较;搭桥术后,病变显著侧相同脑实质区K^(trans)值、血浆容积分数(Volume Plasma,Vp)进行术后术前比较,均采用配对t检验。结果:DCE-MRI中的K^(trans)值评价烟雾病患者侧支循环与DSA结果之间一致性一般(Kappa=0.314,P<0.05);术前病变显著侧大脑半球感兴趣区K^(trans)值较镜像侧升高(t=2.688,P<0.05);搭桥术后一周病变显著侧脑质较术前相同脑实质区K^(trans)值减低,血浆容积分数Vp增高,但K^(trans)值较术前无明显差异(t=1.451,P=0.07>0.05),Vp值较术前具有明显差异(t=2.959,P<0.05)。结论:磁共振动态对比增强(Dynamic Contrast-Enhanced MRI,DCE-MRI)可有效评价烟雾病术前侧支循环及微循环情况、血脑屏障破坏程度及术后微循环改善、血脑屏障恢复状况。

Objective: To evaluate the preoperative collateral circulation and blood-brain-barrier (BBB) damage, microcirculation improvement and BBB recovery after surgery by dynamic contrast- enhanced MRI (DCE-MRI) in patients with Moyamoya disease. Methods: 20 patients with Moyamoya disease diagnosed by Digital Subtraction Angiography (DSA) and/or Computed Tomography Angiography (CTA) underwent conventional MRI, T1enhanced scan and DCE-MRI examination were enrolled in this study. The basal ganglia and radiography canopy layers were divided into22 brain parenchymal sub-regions according to the distribution of blood supply to the anterior, middle, posterior, and perforator arteries of the brain. DSA was used to score the collateral circulation of22 sub-regions (0,1,2 and3 points);DCE-MRI was used to calculate the vascular volume exchange constant (K trans ). K trans was also used to score the sub-regions (0,1,2 and3 points). The K trans and DSA scores of the 22 sub-regions were compared with Kappa consistency test (P< 0.05 as statistical significance);Before surgery, the value of K trans in the hemisphere with more significant lesions was compared with that of the mirror side brain parenchyma;After bypass surgery, the value of K trans and volume fraction of plasma (Vp) on the significant lesion side were compared with that of the same zones of brain parenchyma before surgery. Paired t test was used for comparison. Results: K trans was moderately consistent with the results of DSA in evaluation of collateral circulation in patients with Moyamoya disease (Kappa=0.314,P<0.05);Before surgery, K trans in the hemispheres with significant lesion was significantly higher than that of the mirror side (t=2.688,P<0.05);After surgery, K trans of the same cerebral parenchyma with more obvious lesion decreased compared with that of before surgery. While Vp increased. The difference between K trans was not significant (t=1.451,P=0.07>0.05), while the difference of Vp was significant (t=2.959,P<0.05). Conclusion: DCE-MRI can effectively evaluate the collateral circulation and microcirculation before operation, the damage degree of blood-brain barrier, the improvement of microcirculation after operation, and the recovery of blood-brain barrier in patients with moyamoya disease.