脑血管CT值定量评估对大动脉闭塞的诊断价值

The Diagnosis Value of Quantitative Assessment of Cerebrovascular Density in Large Vessel Occlusion

目的:探索基于薄层CT的脑血管密度定量测量能否作为急性大动脉闭塞的客观诊断标准及其临床应用价值。方法:回顾性分析47例在我院接受急诊机械取栓治疗患者的CT影像和临床资料,并按照年龄和性别一对一匹配一组无大血管闭塞患者作为对照组,由2名医生在多平面重建(MPR)模式下对血管进行评估并测量其CT值,测量区域包括脑动脉高密度征(HAS)段和对侧血管相应位置,对照组测量两侧大脑中动脉对称位置。结果:病例组HAS段血管的CT值明显高于对侧相应位置和对照组,其中病例组HAS段密度范围33~69HU(平均55HU),对侧相应位置血管密度值范围29~51HU(平均40HU);对照组平均CT值约43HU。HAS段与对侧CT值差值以7.55HU为界值诊断急性大血管闭塞的灵敏度为80.4%,特异度为91.5%;以HAS段与对侧CT值的比值1.12为界值诊断的灵敏度为80.4%,特异度为89.4%。结论:基于薄层CT对脑血管CT值的定量评估(差值和比值)或可作为诊断大血管闭塞的客观指标;以HAS段CT值与对侧血管密度差值7.55HU或比值为1.12为界值均表现出较高的灵敏度和特异度。

Purpose:To explore the quantitative measurement of cerebrovascular density based on thin-slice CT as an objective diagnosis index for hyperdense artery sign(HAS)and its clinical application.Methods:The CT images and clinical data of 47 patients received emergency mechanical thrombectomy were analyzed retrospectively.As the control group,a group of patients without large vessel occlusion were collected and matched with those 47 patients one-to-one according to age and gender.Visual assessment and the CT density in Hounsfield units(HU)were evaluated in multi-planar reformation images by two doctors.In the patient group,the measurements were performed in the hyperdense segment of the involved artery and the corresponding position of the contralateral vessels.In the control group,two symmetrical segment of lateral middle cerebral artery were measured.Results:The CT value of HAS segment in patients group was significantly higher than that of the contralateral side and the control group.The density of HAS segment in the patient group ranged from 33 HU to 69 HU,with a mean value of 55 HU,and the density of segment in the contralateral side ranged from 29 HU to 51 HU,with a mean value of 40 HU;the mean value of control group was about 43 HU.When the CT density difference between hyperdense artery and contralateral side 7.55 HU was used as a cut-off to diagnose HAS,the sensitivity was 80.4%and specificity was 91.5%;When the density ratio of hypersense artery density to contralateral density 1.12 was used as a cut-off,the sensitivity was 80.4%and specificity was 89.4%.Conclusion:The quantitative measurements of cerebral vascular CT value based on thin-slice CT may be used as an objective diagnostic index for HAS which suggests possibility of large vessel occlusion.Both of the cutoff values(ie.,difference and ratio)showed high sensitivity and specificity.