Objective To compare the image quality and artifact between 640 - slice and 64 - slice CT coronary angiography in the patients with pacemaker, and to evaluate the success rate and applicability of CT coronary angiography. Methods Twenty - four patients with pacemaker were divided into two groups. Group A ( 16 patient) underwent 640 - slice CT coronary angiography, and Group B ( 8 patient) underwent 64 - slice CT coronary angiography. Image quality and artifact of the fifteen coronary segments were assessed by two blinded observers. Radiation dosage and patient's common information were recorded. Data sets were analyzed using parametric and nonpara-metric statistical tests with the SPSS 13.0 software. Results There was no significant difference in body weight and body height between the two groups. Radiation exposure was significantly higher with 64 - slice CT than with 640 - slice CT ( 13. 8 ± 1. 53 mSv vs 9. 14 ± S.6S mSv; P<0.001) despite significantly higher heart rates in the 640 - slice CT group [61 ±4bpm ( beats per minute) vs 71 ±6bpm; P <0. 001 ] . The rate of available diagnostic images was greater for images obtained with 640 - slice CT than for images obtained with 64 -slice CT(99.06% vs93.27% ; P<0.05). Artifacts were the cause of coronary arteries that cannot be evaluated for coronary MSCT angiography. They were blurring artifact, stairstep artifact, streak artifact, missing data. There were significant differences in these artifacts between the two groups( continuity corrected^2 = 5.009,/* <0.05). Artifacts of group A were mild (94.3% ) , and artifacts of group B were severe artifacts (31.8% ). Conclusion 640 - slice and 64 - slice CT coronary angiography have excellent image quality in patients with pacemaker. 640 - slice CT provides significantly better diagnostic image quality and artifacts of little influence than those of 64 - slice CT, and it had more success rate and applicability of CT coronary angiography.%目的 比较起搏器置入患者行640层容积CT与64层螺旋CT冠状动脉造影的图像质量和伪影,探讨CT冠状动脉造影的成功率和适用性.方法 24例拟行CT冠状动脉造影的起搏器置入病例根据使用设备的不同分为A组(640层CT组)与B组(64层CT组)两组,请两位有经验的评价者双肓评价冠脉15个节段的图像质量以及各种伪影对冠脉节段的影响,同时记录辐射剂量和患者一般资料,并进行统计分析.结果 两组之间的身高、体重等一般影响因素均无统计学差异.尽管A组的心率显著高于B组(A组的心率:71±16次/分；B组的心率:61±4次/分；P＜0.001),但A组的辐射剂量显著低于B组(A组的ED:13.8±1.53mSv:B组的ED:9.14±5.65mSv;P＜0.001).在起搏器置入患者冠状动脉图像可诊断率(1级+2级)的比较上,A组与B组间有统计差异(A组:99.06％,B组:93.27％,连续校正x2=6.572,P＜0.05).影响两组冠状动脉图像质量的伪影有运动伪影、阶梯伪影、金属伪影、数据缺失等,各种伪影对冠状动脉图像质量的影响程度两组间有统计学差异(连续校正x2=5.009,P＜0.05).其中,A组的冠状动脉图像伪影以不影响诊断的轻度伪影为主,占94.3％,中重度伪影节段仅占伪影节段总数的5.78％,而B组的冠状动脉中重度伪影节段占伪影总数的31.8％.结论 起搏器置入患者行CT冠状动脉造影时,640层容积CT与64层螺旋CT均能提供优秀的图像质量,但640层容积CT以较高的图像可诊断率和较轻的伪影干扰而比64层螺旋CT具有更高的成功率和适用性.
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