64层螺旋CT脑动脉、混合脑动静脉和脑静脉血管成像─智能跟踪扫描减影技术

目的:探讨64层螺旋CT智能跟踪扫描减影技术在脑动脉、混合脑动静脉和脑静脉血管成像中的最佳启动扫描阈值和价值。方法:在我院行减影脑血管成像患者共105例,按启动扫描阈值大小分为三组,A组(90HU),共36例;B组(80HU),共34例;C组(70HU),共35例。对整个头部平扫、增强动脉早期和静脉早期扫描获得未减影数据,将动、静脉早期数据减去平扫数据获得减影动脉期、减影混合动静脉期数据,静脉早期数据减去动脉早期数据获得减影静脉期数据。采用VR、MIP重建减影血管图像。根据血管图像质量分为四级并分别记分。结果:(1)三组患者血管密度减影动脉期动脉较静脉显著高,减影混合动静脉期动脉和静脉均较高,减影静脉期静脉较动脉显著高。减影动脉期、减影混合动静脉期和减影静脉期血管密度组间比较相似,但减影动脉期C组动脉密度最低,减影混合动静脉期C组动脉密度最高、静脉密度最低,减影静脉期C组静脉密度最高。(2)减影图像与未减影图像相比去除了动脉、静脉相互的及颅骨的干扰,对脑动、静脉解剖结构显示清楚。①减影动脉期三组脑动脉图像质量均无0分,有诊断价值的病例均占100%,C组较A、B组图像质量稍好;②减影混合动静脉期三组混合脑动静脉图像质量均无0分,有诊断价值的病例均占100%,B、C组较A组图像质量好,B、C组图像质量相似;③减影静脉期A组脑静脉图像质量有诊断价值的病例占69.5%,B组脑静脉图像质量有诊断价值的病例占88.3%,C组脑静脉图像质量有诊断价值的病例占100%,C组图像质量明显好于A、B组。结论:64层螺旋CT智能跟踪扫描减影技术能分别显示脑动静脉、混合脑动静脉和脑静脉,以动脉期启动扫描阈值70HU图像质量最好,全部血管均有诊断价值,特别是对脑静脉的显示,值得临床推广应用。

64-rows helical CT intelligent tracing scanning subtraction angiography research in cerebral arteries, mixing cerebral vessels and cerebral veins

Objective：To investigate the best start scanning threshold and the value with 64-row helical CT intelligence tracking scanning substraction angiography in cerebral arteries, mixing cerebral vessels and cerebral veins. Methods： 105 cases, which underwent cerebral imaging by subtraction angiography in our hospital, were divided into three groups ac- cording to the start scanning threshold, i. e. , group A （90 HU） had 36 cases, group B （80 HU） had 34 cases, and group C （70 HU）had 35 cases. All cases were performed unenhanced, early arterial and venous phase enhanced scanning to ac- quire no-subtracted data. The early arterial phase and venous phase enhanced data subtracted the unenhanced data to obtain cerebral arterial or merged arteriovenous subtracted data. The early venous phase enhanced data subtracted the early arte- rial phase enhanced data to acquire the subtracted cerebral venous data. Volume rendering （VR） and maximum intensity projection （MIP） were used to reconstruct vessels, which were further classified into four grades according to the image quality and scored respectively. Results： （l） In arterial phase, the vascular density of artery was significantly higher than that of venous vein, in subtraction mixed phase, the arterial density was as the same as the venous density, and the subtraction density was significantly higher than that of artery in venous phase of patients in three groups. In subtraction arte-rial phase, subtraction mixed phase and subtractiQn vein phase, the vascular density was similar among the groups. However, in arterial phase, the arterial density in group C was lowest, in mixed phase, the arterial density was lowest and venous density was highest in group C, in venous phase, the venous density of group C was highest. （2） When the subtracted images were removed the mutual interference between artery and vein and, also, removed the interference of bone in the same time, anatomical structure of brain artery and vein was showed clearly. （!） None of subtraction arterial image quality in three groups was zero point in subtraction arterial phase, with 100% of diagnostic value. The image quality in group C and B group was slightly better;@ As for the mixed arteriovenous images quality of three groups in subtraction mixed phase, there was no zero-point case, with the diagnostic value of 100%. The image qualities of B, C group were better than those in group A. The image qualities in group B were similar to thise in C; ③In substraction vein phase, the vein images quality of group A, which had the diagnostic value, accounted for 69.5%, the vein image quality of group B, which had di- agnostic value, for 88.3%, and the image quality in group C, which had diagnostic value, for 100% The image quality of group C was significantly better than that in group A or B. Conclusion： 64-rows heli- cal CT scanning subtraction intelligent tracing technique can separately showed that cerebral arteries, mixing cerebral ves- sels and cerebral veins. To start scanning threshold arterial at 70 HU, the image quality is best, in which all vessels have diagnostic value, especially to display cerebral veins, being worth applying in clinic practice.