1H-磁共振波普成像联合弥散加权成像、3D-动脉内源性标记对急性脑梗死缺血半暗带的评估价值

目的探讨¹H-磁共振波谱成像（MRS）联合弥散加权成像（DWI）、3D-动脉内源性标记（ASL）的磁共振成像方法，对评估急性脑梗死患者缺血半暗带的应用价值。 方法收集绵阳市第三人民医院2016年10月至2018年3月诊断为急性脑梗死且还未进行临床干预的患者，入组的31例急性脑梗死患者，在症状出现后最短时间内接受DWI、T1加权成像（T1WI）、T2加权成像（T2WI）、磁共振成像液体衰减反转恢复序列（FLAIR）、3D-ASL及¹H-MRS序列扫描，通过ASL-DWI不匹配区来判断患者脑梗死病灶周围的缺血半暗带的范围，再利用¹H-MRS对梗死灶中心区、缺血半暗带及梗死周围正常区的代谢产物浓度［乳酸（Lac）、N-2酰-天门冬氨酸（NAA）、胆碱（Cho）及肌酸（Cr）］进行分析，采用配对样本t检验比较不同区域的Lac、NAA、Cho及Cr的代谢物浓度差异。 结果本研究的31例急性脑梗死患者中，有26例患者ASL低灌注面积大于DWI信号异常区面积，5例患者ASL低灌注面积约等于DWI信号异常区面积。脑梗死中心区的Lac、NAA、Cho及Cr峰值分别为44.79±16.90、25.34±12.12、34.44±8.24、27.91±7.83；缺血半暗带的Lac、NAA、Cho及Cr峰值分别为22.57±8.57、46.64±10.41、51.37±10.86、36.86±6.00；脑梗死周围正常区的Lac、NAA、Cho及Cr峰值分别为6.54±3.34、58.78±9.01、48.02±7.93、39.02±4.74。脑梗死中心区的Lac、NAA、Cho及Cr峰值明显低于缺血半暗带，差异均具有统计学意义（P<0.05）。脑梗死周围正常区与缺血半暗带相比，Lac峰值较高，NAA峰值较低，差异均具有统计学意义（P<0.05）；而Cho及Cr峰值2者差异无统计学意义（P均>0.05）。 结论¹H-MRS联合DWI、3D-ASL可以更准确的评估急性脑梗死患者缺血半暗带的存在及其物质代谢变化，为急性脑梗死患者的临床治疗方式的选择提供了更好的影像学依据。

~1H-MRS combined with DWI and 3D-ASL for evaluation of ischemic penumbra of acute cerebral infarction

ObjectiveTo assess the value of proton magnetic resonance spectroscopy (¹H-MRS) combined with diffusion-weighted imaging (DWI) and three-dimensional arterial spin labeling (3D-ASL) magnetic resonance imaging in the evaluation of ischemic penumbra in patients with acute cerebral infarction. MethodsThis study included 31 patients with acute infarction. DWI, T1WI, T2WI, FLAIR, 3D-ASL, and ¹H-MRS sequence scans were performed within the shortest time after symptoms appeared. The extent of the ischemic penumbra around the patient's infarcted lesion was determined by the ASL-DWI mismatch zone. ¹H-MRS was used to analyze the metabolite concentrations (lactic acid [Lac], acetyl aspartate [NAA], choline [Cho], and creatine [Cr]) in the central region of the infarct, the ischemic penumbra, and the normal area around the infarct. The concentrations of Lac, NAA, Cho, and Cr in different regions were compared by the paired sample t-test. ResultsOf the 31 patients with acute cerebral infarction in this study, 26 patients had an ASL low perfusion area that was larger than the DWI signal abnormal area, and 5 patients had an ASL low perfusion area that was approximately equal to the DWI signal abnormal area. The peaks of Lac, NAA, Cho, and Cr in the central region of cerebral infarction were 44.79±16.90, 25.34±12.12, 34.44±8.24, and 27.91±7.83, respectively, and the corresponding values in the ischemic penumbra and the normal area around the infarction were 22.57±8.57, 46.64±10.41, 51.37±10.86, and 36.86±6.00, and 6.54±3.34, 58.78±9.01, 48.02±7.93, and 39.02±4.74. The peaks of Lac, NAA, Cho, and Cr in the central area of cerebral infarction were significantly lower than those in the ischemic penumbra (P<0.05). Compared with the ischemic penumbra, the normal area around the infarction had a significantly higher Lac peak and significantly lower NAA peak (P<0.05), although there was no statistical difference in Cho and Cr peaks. Conclusion¹H-MRS combined with DWI and 3D-ASL can more accurately assess the presence of ischemic penumbra and its metabolic changes in patients with acute cerebral infarction, providing a better imaging basis for selecting optimal clinical treatment for patients with acute cerebral infarction.