多层螺旋CT对冠状动脉支架的评价及其成像质量控制

Image quality control of MSCT in the evaluation of coronary artery stent

目的研究多层(16层)螺旋CT(muhi slice spiral CT,MSCT)冠状动脉造影成像在评价冠状动脉支架通畅性的临床意义,并分析影响其成像质量的因素。方法采用MSCT对32例冠状动脉支架患者行冠状动脉成像检查,以多种方式重建显示冠状动脉支架的位置、形态、术后再狭窄等。其中7例经X线冠状动脉造影进一步证实。将CT冠状动脉图像质量分三级予以评价,分析其影响图像质量的因素。结果MSCT显示所有32例患者41个冠状动脉支架的形态、位置,其中5个支架术后出现再狭窄;7例患者9个支架与冠状动脉造影对照,诊断符合率为88.9%;图像质量优良率为87.5%(28/32例),心率<60/min、61～70/min和>71次/ min图像质量优良率分别占94.7%、88.9%和50.O%,三种不同心率对图像质量显示有显著性差异(X^2=16.354,P<0.01)。结论MSCT冠状动脉成像是一种较可靠的冠状动脉支架无创性评价方法,对支架开通性显示较好,但对支架内情况显示受限,图像质量受心率等因素影响,质量控制是关键。

Objective To study the clinical significance of using MSCT （16 multi slice spiral CT, MSCT） to evaluate the patency of coronary arterial stent, and to explore the factors contributing to the image quality. Methods 32 patients with coronary arterial stent implantation received MSCT. The shape and position of the stent and the situation of restenosis were checked with several methods. Of the 32 patients, the results in 7 cases were further verified by X-ray coronary artery angiography. The image qualities were classified in three grades. The influence factors contributing to imaging quality were analyzed. Results The rate of good image quality for MSCT coronary artery angiography was 87.5% （28/32）. The rate of good image quality for the patients with heart rate less than 60 was 94. 7%, for those with heart rate of 61 -70 was 88. 9%, and for those with heart rate over 70 was 50. 0%, there existed significant differences （χ^2=16. 354, P〈0. 01） among three groups. The shape and position of all the 41 stents （in 32 patients） were well showed by MSCT. Restenosis was found in 5 stents. In 7 patients （with 9 stents） MSCT images were compared with conventional coronary artery angiography. The coincident rate of MSCT with angiography was 88. 9%. Conclusion MSCT coronary artery angiography is a reliable and non-invasive examination to evaluate coronary artery stent. It can display the patency of stent well, while it is limited in value in showing the stent lumen. The quality control is a key for successful MSCT coronary artery angiography, because it can be influenced by many factors （such as heart rate, etc. ）.