DWI、MRA在急性脑缺血中的联合诊断价值

目的探讨磁共振弥散加权成像（DWI）与磁共振血管成像（MRA）在急性期脑缺血中的联合诊断价值。方法收集经临床和影像学确诊为急性脑梗死的患者40例,所有患者行常规MRI、FLIAR、DWI及MRA检查。对MRA原始图像进行最大密度投影（MIP）重建,选取病灶中心和健侧相应部位8×8像素大小区域,测定各自的表观扩散系数（ADC）,并计算rADC值。结果 40例患者的DWI图像均显示与临床症状及体征相符的病灶,尤其是在超急性期,病灶具有较高的信号强度和清晰度。MRA检查均获得清晰血管图像,结果显示动脉硬化3例,动脉狭窄或闭塞28例;40例中,24例大面积病灶的血管病变阳性率为100%。DWI显示病灶解剖定位均与MRA上血管异常解剖定位有较好的一致性。结论 DWI对脑梗死超急性期、急性期均有很高的敏感性,MRA对颅内大血管及其部分分支的狭窄或闭塞情况均能很好地显示。通过DWI和MRA联合扫描进行比较,可以对应显示同一区域脑实质和脑血管情况,进一步判定责任血管。

Diagnostic value of diffusion-weighted imaging combined with magnetic resonance angiography in acute cerebral ischemia

Objective To discuss the diagnostic value of magnetic resonance diffusion-weighted imaging(DWI)combined with magnetic resonance angiography(MRA)in acute cerebral ischemia.Methods Forty patients who were finally diagnosed as acute cerebral infarction were selected.All of them received the conventional MRI,FLIAR,DWI and MRA examinations.Reconstruction of maximum intensity projection(MIP)was made on the original MRA image.Areas with 8 × 8 pixel size in the center and at the uninjured side of the focus nidus were selected to detect the apparent diffusion coefficient(ADC)and calculate the rADC value.Results The DWI images of the 40 patients displayed their focus nidi which were consistent with the clinical symptoms and physical signs.Especially in the hyperacute stage,the focus nidus had high signal strength and clarity.Clear vascular images were obtained by MRA examination which showed atherosclerosis in 3 cases and arterial occlusion in 28 cases.Among the 40 cases,the positive rate of vascular lesion in a large area of focus nidus was 100% in 24 ones.The DWI showed anatomical location of the focus had good consistency with the anatomical location of vascular abnormalities on MRA.Conclusion DWI has a highly sensitivity to cerebral infarction in hyperacute and acute stages.MRA can well diaplay the stenosis or occlusion in intracranial great vessels and part of the branches.Through comparing the results of DWI combined with MRA with those of DWI or MRA alone,the situations of cerebral parenchyma and vessels at the same area can be correspondingly displayed,and the related blood vessels can be further determined.