运用 MR 血管成像及灌注加权成像评价烟雾病责任血管、术后重建血管及手术前后脑血流动力学变化

Application of MR angiography and perfusion weighted imaging in the evaluation of abnormal vessels in Moyamoya disease, cerebral revascularization after operation and cerebral hemodynamics during the perioperative period

目的：探讨MRA评价烟雾病责任血管及术后重建血管价值，以及灌注加权成像（PWI）评价血管重建术前后脑血流动力学变化的价值。方法搜集经DSA证实并行单侧血管重建术的24例烟雾病患者，均在术前及术后行MRA及PWI检查，其中9例患者术后行DSA检查。由3名经验丰富的放射科医师对MRA图像与DSA图像进行比较。测量患者手术侧及对侧大脑中动脉（MCA）分布区、小脑对照区的灌注参数，包括脑血流量（ CBF）、脑血容量（ CBV）、平均通过时间（ MTT）及延迟时间（ DT），计算术侧MCA分布区/对侧MCA分布区及术侧MCA分布区/小脑对照区的灌注参数相对比值（ rCBF、rCBV、rMTT及rDT值）。采用配对t检验比较手术前后正态分布的PWI灌注参数相对值的差异。结果 MRA在显示颈内动脉及其大分支血管狭窄、烟雾血管及重建血管方面与DSA相仿，DSA显示侧支血管优于MRA，MRA原始图像可以提供颅脑解剖及病变信息。烟雾病患者术后手术侧MCA分布区与对侧镜像区的rCBF（1.30±0.27）及rCBV（1.26±0.21）明显高于术前rCBF（0.73±0.15）及 rCBV（0.98±0.12）（t 值分别为-7.91、-6.64，P 值均＜0.05）；rMTT （1.06±0.20）及rDT（1.07±0.18）明显低于术前rMTT（1.53±0.34）及rDT（1.40±0.26）（t值分别为5.62、5.40，P值均＜0.05）。术后手术侧MCA分布区与小脑对照区的rCBF（1.93±0.34）及rCBV （2.25±0.35）明显高于术前的rCBF（0.88±0.18）及rCBV（1.16±0.22）（t值分别为-3.04、-3.06， P值均＜0.05）；术后rMTT（1.13±0.29）及rDT（1.29±0.12）明显低于术前的rMTT（1.88±0.19）及rDT（3.29±0.47）（t值分别为4.01、4.72，P值均＜0.05）。结论 MRA可以作为一种评估烟雾病责任血管及术后重建血管的安全可靠方法。 PWI能检测烟雾病患者脑缺血部位及程度，可作为血管重建术的疗效评价的重要方法。

Objective To evaluate the clinical value of MRA on the abnormal vessels in Moyamoya and cerebral revascularization , and to evaluate PWI in the observation of cerebral hemodynamics before and after cerebral revascularization.Methods Twenty-four patients with Moyamoya disease ascertained by DSA received cerebral revascularization on one side.MRA and PWI were performed for all patients before and after the operation , while DSA was performed after operation in nine patients to compare the images of MRA and DSA by three experienced radiologists.Perfusion parameters in terminal branches of middle cerebral artery （ MCA） on the operative side were compared with those on the contralateral sides and the cerebellum , including cerebral blood flow （CBF）, cerebral blood volume （CBV）, mean transit time （MTT）, and delay＆amp;nbsp;time （ DT） , as well as relative ratio （ values on the operative side/values on the contralateral side , and values on the operative side/values on the cerebellar region ） of perfusion parameters （rCBF, rCBV, rMTT and rDT） were calculated.Comparisons of the data between different groups were performed using paired Student′s t test.Results MRA was similar to DSA in displaying the internal carotid artery , main branches stenosis, Moyamoya vessels, and cerebral revascularization.DSA was better in displaying collateral vessels than MRA, but primary images of MRA provided anatomic and pathologic information of cerebral parenchyma.After the operations , rCBF （1.30 ±0.27） and rCBV （1.26 ±0.21） of MCA perfusion regions on the operative and the contralateral sides were higher than rCBF （0.73 ±0.15） and rCBV （0.98 ±0.12） before the operation significantly （t=-7.19,-6.64,P〈0.05）.rMTT （1.06 ±0.20） and rDT （1.07 ± 0.18） after the operation were lower than rMTT（1.53 ±0.34）and rDT （1.40 ±0.26） before the operation （t=5.62,5.40,P〈0.05） .In MCA perfusion regions on the operative and cerebellar sides , rCBF（1.93 ± 0.34）and rCBV（2.25 ±0.35）were higher than rCBF（0.88 ±0.18）and rCBV（1.16 ±0.22）（t=-3.04,-3.06,P〈0.05） before the operation.rMTT （1.13 ±0.29） and rDT （1.29 ±0.12） were lower than rMTT （1.88 ±0.19 ） and rDT （ 3.29 ±0.47 ） before the operation （ t =4.01, 4.72, P 〈0.05 ）.Conclusions MRA is a safe , reliable method to evaluate abnormal vessels and cerebral revascularization after the operation in moyamoya disease.PWI can detect poor cerebral perfusion , and can be used for assessment of the effect of cerebral revascularization.