3D-ASL联合弥散加权成像、血管成像可准确评估急性缺血性脑梗死患者的缺血半暗带区域

  目的  探究三维动脉自旋标记灌注成像（3D-ASL）联合弥散加权成像（DWI）、血管成像（MRA）对急性缺血性脑梗死缺血半暗带区域（IP）的评估价值。  方法  选取2021年1月~2022年6月本院收治的急性缺血性脑梗死患者62例，所有患者均接受3D-ASL、DWI、MRA扫描，根据病灶最大层面DWI高信号面积、ASL异常灌注面积评估患者是否存在IP，根据患者发病至首次MRI检查时间（T）将患者分为超急性期（T<6 h）和急性期（6 h≤T≤24 h）。记录患者中心梗死区、IP区与IP对侧镜像区的表观扩散系数（ADC）、脑血流量（CBF）值，根据MRA图像对血管狭窄程度进行分级。  结果  急性缺血性脑梗死患者病灶DWI表现为斑点状或小片状高信号，48例患者3D-ASL异常灌注面积明显大于DWI异常高信号面积，显示存在IP区；MRA显示颅内某支主干动脉节段性狭窄，远端血管明显变细甚至消失，部分显示血管无明显异常。患者不同区域CBF、ADC值比较:中心梗死区  结论  3D-ASL联合DWI、MRA检测可准确评估急性缺血性脑梗死患者IP区的存在和血管狭窄程度，有利于梗死临床精准化治疗方案的选择。 

Value of 3D-ASL combined with DWI and MRA in assessment of ischemic penumbra in acute ischemic cerebral infarction

  Objective  To investigate the value of three-dimensional arterial spin labeling (3D-ASL) combined with diffusionweighted imaging (DWI) and magnetic resonance angiography (MRA) in assessment of ischemic penumbra (IP) in acute ischemic cerebral infarction.  Methods  A total of 62 patients with acute ischemic cerebral infarction were treated in the hospital from January 2021 to June 2022. All patients underwent 3D- ASL, DWI and MRA. The presence or absence of IP was determined according to the area of DWI hyperintensity at the maximum slice of the lesion and the abnormal perfusion area of ASL. According to the time from onset to first MRI, the patients were divided into the hyperacute phase (T<6 h) group and the acute phase (6 h≤T≤24 h) group. The apparent diffusion coefficient (ADC) values and cerebral blood flow (CBF) of central infarct area, IP area and contralateral area of IP were recorded. The degree of vascular stenosis was graded according to MRA images.  Results  The lesions of patients with acute ischemic cerebral infarction showed spotted or small pieces of high signals on DWI. 48 patients had significantly larger abnormal perfusion area on 3D-ASL than abnormal high signal area on DWI, which indicated the existence of IP area. MRA showed segmental stenosis of a intracranial main branch, significantly thinned or even disappeared distal blood vessels, and some blood vessels without obvious abnormalities. The CBF and ADC values of central infarct area, IP area, and contralateral area of IP increased in order (P<0.05). The rCBF and rADC values in hyperacute phase were higher than those in acute phase (P<0.05). MRA showed that vascular stenosis mainly was grade 0 in patients with IP, and mainly was grade 3 in patients without IP (P<0.05).  Conclusion  3D-ASL combined with DWI and MRA can help to accurately assess the presence or absence of IP area and the degree of vascular stenosis in patients with acute ischemic cerebral infarction, which is beneficial to the selection of clinical treatment plan.