脑血管电子束CT(EBCT)成像技术的初步探讨

Preliminary Investigation on Scanning Protocols of Cerebrovascular EBCT

目的：探讨合理的脑血管电子束ＣＴ（ＥＢＣＴ）的检查模式。材料与方法：选择７２例ＥＢＣＴＡ检查结果正常者随机分组、对照，进行前瞻性研究，采用ＩｍａｔｒｏｎＣ１５０ＥＢＣＴ扫描仪，连续容积（ＣＶＳ）和步进式（ＳＶＳ）两种扫描模式，３～５ｍｌ／ｓ注射速度，重建方法选择最大信号强度投影（ＭＩＰ）和表面遮盖法（ＳＳＤ）。结果：（１）同一剂量下，ＣＶＳ扫描组的不同脑血管部位ＣＴ值要高于相同条件下的ＳＶＳ扫描组（Ｐ＜０．０１）；同一扫描模式组内，５ｍｌ／ｓ组的不同脑血管部位ＣＴ值高于３ｍｌ／ｓ组（Ｐ＜０．０１）；３ｍｌ／ｓＣＶＳ扫描组的不同脑血管部位ＣＴ值与５ｍｌ／ｓＳＶＳ组无明显差异（Ｐ＞０．０５）；（２）各组对于各级脑血管的主干及１～３级分支显示率为１００％，对于大脑中动脉４～５级分支５ｍｌ／ｓＣＶＳ组显示率仍高达９４．４％，前、后交通动脉的显示率存在较大差异。结论：注射速度５ｍｌ／ｓ，延迟时间由小剂量试验而定（一般为１２～１６ｓ），层厚３ｍｍ，间隔１．５ｍｍ，ＣＶＳ重叠扫描模式是较为理想的电子束ＣＴ检查模式。

Objective: To investigate the optimal scanning protocols of cerebrovascular EBCT.Materials and Methods:A randomized, controlled and prospective study of 3D EBCTA was conducted in 72 normal subjects. Using an Imatron C 150 EBCT scanner, continuous volume scanning (CVS) and step volume scanning (SVS), together with 3 or 5ml/s contrast injection, were performed. Images were reconstructed with maximum intensity projection (MIP) and shaded surface display (SSD).Results:(1)When the same dose was used, the CT values of various cerebrovascular site of CVS group were higher than that of SVS group (P<0.01). When the same scanning model was used, the CT values in 5ml/s group were higher than that in 3ml/s group (P<0.01), while no significant difference in CT values was found between 3ml/s CVS group and 5ml/s SVS group (P>0.05); (2)All main trunk and 1～3 branches of cerebral arteries in every group were well visualized. In 5ml/s CVS group, 94.4% of 4～5 branches of middle cerebral arteries were demonstrated. Significant difference in visualizing was found between anterior communicating artery and posterior communicating artery.Conclusion: