多层螺旋CT评价冠状动脉支架的体外实验

目的研究多层螺旋CT(MSCT)对冠状动脉支架的成像效果.方法将不同类型及内径的支架置入硅管内,制作成冠脉内支架模型.观察不同材料支架、灌注液、内径及MSCT重建层厚对支架成像效果的影响,并与冠脉内超声(ICUS)结果比较.结果钽制支架不能显示,而内径3 mm以上的不锈钢支架可以清晰的由MSCT显示;MSCT灌注对比剂时所测得的支架内径值明显低于灌注蒸馏水的结果(P＜0.05);3 mm和4 mm不同内径的支架相比,灌注对比剂时的剖面曲线最低CT值明显高于灌注蒸馏水的值(P＜0.05).且无论是灌注蒸馏水还是对比剂,内径4 mm的支架剖面曲线最低CT值都明显低于内径3 mm的支架(P＜0.05);与1.0 mm重建层厚相比,0.5 mm重建层厚可得到较清晰的图像;MSCT和ICUS对支架内径的测定结果有高度相关性(r=0.85,P＜0.05).结论MSCT可以对冠脉支架的形态进行评价,但其成像受支架材料、内径及重建条件的影响.

Evaluation of coronary artery stents by multi-slice helical CT: in vitro experiment

Objective To evaluate the lumen visualization of different kinds of coronary artery stents using multi slice helical CT (MSCT). Methods The stents made of different materials were implanted into silicon tubes to make coronary phantom (CP). Stents were scanned by a 4 slice detector scanner. The effects of different stent material, stent diameter and reconstructed slice thickness on the image quality were evaluated, and the measurements of inner stent diameters by MSCT were compared with the results of intracoronary ultrasound (ICUS). Results Tantalum stent could not be evaluated by MSCT and stainless steel stent over 3 mm inner diameter could be clearly visualized. The measurement of stent diameters filled with Omnipaque was significantly lower than filled with water ( P <0.05) when scanned by MSCT. The lowest CT value of profile curves filled with water was lower than filled with Omnipaque ( P <0.05), and the lowest CT value of 4 mm diameter stents was significantly lower than 3 mm diameter stents ( P <0.05) either by water or by Omnipaque. For coronary stent visualization, 0.5 mm slice thickness was better than 1.0 mm. The stent diameters measured by MSCT were significantly correlated with those measured by ICUS ( r=0.85, P <0.05). Conclusion MSCT can be used to evaluate the stent status, but the stent material, stent diameter, stent strut and reconstructed slice thickness should be considered.