ASL与DWI在急性缺血性脑血管病中的诊断价值  

The Diagnostic Value of ASL and DWI in Acute Ischemic Cerebrovascular Disease

作　　者：徐敏[1] 杨军乐[1] 邬小平[1] 周蕻[1] 赵雅琴[1] 贺长安[1] 

机构地区：[1]西安市中心医院影像中心,710003

出　　处：《现代医用影像学》2014年第5期461-465,共5页Modern Medical Imageology

摘　　要：目的:探讨动脉自旋标记成像(ASL)及弥散加权成像(DWI)两种磁共振成像方法在急性缺血性脑血管病诊断中的价值。材料与方法:通过GE HDx 1.5T双梯度磁共振,对22例急性脑缺血患者分别行常规MR(包括T1FLAIR、T2WI)、3D-TOF MRA、DWI(b值取1000s/mm2)及3D ASL序列,观察ASL与DWI序列病变区最大层面面积的大小及与MRA之间的关系,并进一步测量缺血区域与对侧镜像层面的脑血流(CBF)值,计算相对脑血流值(r CBF)=缺血区域CBF/对侧镜像层面CBF,r CBF在0.9-1.1之间,定义为灌注正常,r CBF>1.1定义为高灌注,r CBF<0.9定义为低灌注。结果:22例急性脑缺血患者中,小面积缺血10例,DWI表现为斑点状或小片状高信号,其中4例ASL为低信号,DWI面积与ASL面积相近,另6例DWI显示为高信号,ASL无阳性表现,小面积梗死病例中MRA均无明显异常;大面积缺血10例,DWI表现为一个供血区大片状高信号或多个供血区域斑点状、小片状高信号,ASL均为低信号,ASL显示病变区最大层面面积大于DWI面积,其中2例病变周围皮层区ASL存在局部高信号影,大面积缺血病例中MRA存在不同程度的脑动脉硬化或动脉闭塞;另2例患者DWI表现为阴性,而ASL为低信号,即TIA患者,MRA显示1例表现为大脑中动脉硬化,1例表现为颈内动脉闭塞。对于6例ASL为阴性病例者,缺血区CBF值为(40.47±1.94)ml/100g*min,对侧镜像区为(42.74±1.49)ml/100g*min,r CBF为0.95±0.04;16例ASL表现为低信号的病例,其中1例DWI表现为脑干及双侧小脑半球局部高信号,ASL表现为双侧小脑半球均为低信号,两侧CBF分别为24.13 ml/100g*min、23.76 ml/100g*min,因为无法测量该患者正常小脑CBF值,从而无法计算r CBF,本例患者MRA表现为椎基底动脉及双侧大脑后动脉闭塞;其余15例病例测量病变区CBF值为:(22.29±0.95)ml/100g*min,对侧镜像层面CBF为:(44.96±2.89)ml/100g*min,r CBF为0.52±0.03,局部皮层高信号区CBF为233.07 ml/100g*min,对侧镜像区为61Purpose： To explore value of arterial spin labeling （ASL） and diffusion weighted imaging （DWI） in the diagnosis of acute ischemic cerebrovascular disease. Materials and Methods： 22 patients with acute isehemic cerebrovaseular disease underwent conventional MR examinations （including T1Flalr and T2WI）, 3D -TOF MRA, DWI（ b value is 1000s/mm^2 ） and ASL sequence by GE HDx 1.5T twinspeed MR. Observed the areas in the largest slice on DWI and ASL sequence, the relationship with MRA, and further measured the cerebral blood flow （CBF） values on ischemia areas and the areas of the contralateral mirror. Then calculated the relative value of the cerebral blood flow （rCBF） = CBF of ischemia area /CBF of the mirror side, if the rCBF between 0. 9 and 1.1, defined as normal perfusion, if the rCBF 〉 1.1, defined as high perfusion, and if the rCBF 〈 0. 9, defined as low perfusion. Results： In all 22 cases of acute cerebral ischemia patients, 10 cases were small areas of ischemia, DWI showed punctated or small patches high signal. There were 4 cases that ASL Were low perfusion and DWI area close to ASL area, and the other 6 cases ASL and MRA had not positive performance; 10 cases of large area of ischemia, DWI showed a large patch of high signal or multiple blood supply area punctuated and platelet high signal, ASL were low signal and their areas were bigger than the DWI areas, there were 2 cases had high local signal on ASL around the cortex and different degree cerebral arterial stiffness or arterial occlusion on MRA; The other two patients showed negative DWI, and ASL was low signal, MRA displayed one case brain arteriosclerosis, one case occlusion of the internal ca- rotid artery; For the six cases of patients who were negative ASL, ischemic area CBF values （40. 47 ± 1.94 ） ml/100g ＊ min, contralateral mirror area was （42.74 ± 1.49）ml/100g ＊ min, rCBF was 0. 95 ± 0. 04; 16 ASL cases showed low signal, ASL showed bilateral cerebellar hemispheres low signal on both sides , CBF we

关 键 词：动脉自旋标记 弥散加权成像 缺血性脑血管病 CBF 

分 类 号：R743.31[医药卫生—神经病学与精神病学]