十六层螺旋CT冠状动脉造影的初步探讨

目的 探讨十六层螺旋CT冠状动脉造影的技术操作要点和临床应用价值。方法 对64例临床可疑冠心病及5例置入冠状动脉支架的患者进行十六层螺旋CT心电门控平扫及增强扫描。对所有患者行冠状动脉钙化积分扫描,用增强扫描重建像行多曲面重建(MPR)、最大密度投影(MIP)重建及容积再现技术(VRT)重建,其中10例可疑冠心病患者有常规冠状动脉造影作对照。总结CT冠状动脉造影的评价方法和显示情况,分析影响冠状动脉成像的原因。对5例患者置入的7个冠状动脉支架另行垂直切面MPR及MIP重建,并行仿真血管内窥镜重建,观察支架通畅情况。结果 拟订出四步扫描步骤。十六层螺旋CT平扫可测定钙化积分,增强扫描MPR、MIP及VRT重建像能多角度各向同性地显示冠状动脉的所有1级、绝大部分2、3级以及部分4级分支。MPR及MIP图像对冠状动脉分支的显示优于VRT图像。用VRT重建像评价图像质量79．7％(55例)为1级,10．1％(7例)为2级,10．1％为3级。图像质量的影响因素有主动脉根部造影剂浓度、心率、有无心律不齐和患者屏气情况等。评价10例冠状动脉狭窄情况,与常规冠状动脉造影结果基本相符。7个支架均显示良好,6个支架通畅,1个不通畅。结论 十六层螺旋CT冠状动脉造影可一次检查完成冠状动脉钙化积分和狭窄评价,也可评价支架通畅情况,是一种无创、简便、优良的冠状动脉成像方法。

Coronary angiography with sixteen-slice spiral CT: an initial study

Objective To evaluate the scanning technique and primary clinical value of sixteen-slice spiral CT coronary angiography. Methods Plain and enhanced sixteen-slice spiral CT imaging was performed in 69 patients, including 64 cases of suspected coronary heart disease and 5 cases of coronary stent. Calcium scoring with plain scan images and MPR, MIP and VRT reconstruction with enhanced scan images were made in all cases, among which 10 underwent conventional coronary angiography. The demonstration and stenosis of coronary arteries were evaluated. The factors influencing the image quality were analyzed. Additional MPR and MIP reconstruction of slices perpendicular to the stent and virtual endoscopy of stent were made in 7 stents of the 5 cases of coronary stent. The patency of the stents was evaluated. Results A four-step scanniing procedure was devised. Coronary calcium score could be got by plain scanning with sixteen-slice spiral CT angiography. All of the primary, most of the secondary and tertiary, and part of the fourth level branches of coronary artery could be shown isotropically with MPR, MIP and VRT reconstruction images of enhanced scanning. MPR and MIP were better than VRT in demonstrating small branches. Evaluated by VRT image, the image quality of 79.7% of the patients were first class, 10.1% second class, and 10.1% third class. The image quality was correlated to the contrast concentration in the root of aorta, heart rate, existence or absence of arrythmia, and the patient's breath-holding ability. Stenosis of coronary arteries was evaluated by sixteen-slice spiral CT imaging in 10 cases, with a result comparable to that by conventional coronary angiography. The stents were well shown, six stents being evaluated as patent, while one not. Conclusion Sixteen-slice spiral CT coronary angiography is a noninvasive,simple and good method. Coronary calcium score and coronary artery stenosis can be evaluated with one study. The patency of stents can also be evaluated.