心率对640层动态器官容积 CT 冠状动脉成像图像质量及射线剂量的影响  

The impact of heart rate on image quality and radiation dose of coronary angiography using 640-slice dynamic volume CT

作　　者：龚佳英 覃杰[2] 曹务腾[1] 熊斐[1] 林扬皓 王馨华[1] 朱珊珊[1] 杜彩虹[1] 周智洋[1] 

机构地区：[1]中山大学附属第六医院放射科,广东广州510655 [2]中山大学附属第三医院放射科

出　　处：《实用放射学杂志》2014年第12期1993-1996,2023,共5页Journal of Practical Radiology

基　　金：广东省科技厅科技计划资助项目（2011A030400003）。

摘　　要：目的：回顾性分析不同心率对640层动态器官容积 CT 冠状动脉成像的图像质量及射线剂量的影响。方法对本院拟诊冠心病或进行体检的461例患者行640层容积 CT 冠状动脉成像,根据心率不同将其分为2组,A 组心率〈65次/min（337例）,B组心率65~122次/min（124例）,通过分析15个主要冠状动脉节段对图像质量进行评价,Ⅰ级代表优良,Ⅱ级为合格,Ⅲ级为差。同时对有效射线剂量进行评估。结果A 组和 B 组共461例（100%）患者均顺利完成640层容积 CT 冠状动脉成像,共有6915（15×461）个冠状动脉节段。可评估冠状动脉节段占94.5%（6535/6915）,冠状动脉节段管径太小（≤1.5 mm）难以评估者占5.5%（380/6915）。A 组和 B 组图像质量被评为Ⅰ级的分别占90.5%（305）和74.2%（92）,Ⅱ级占9.5%（32）和21.0%（26）,Ⅲ级占0%和4.8%（6）。2组间Ⅰ、Ⅱ级图像质量差异有统计学意义（P 〈0.001）。此外,A 组中32例（9.5%）患者出现轻微运动伪影但不影响观察,而 B 组中26例（21%）患者由于出现较大程度的伪影而被评为Ⅱ级,但仍能满足诊断要求。全部病例无阶梯伪影。本组病例 B 组的有效射线剂量较 A 组高32.05%（7.91 mSv±0.34 mSv vs 5.99 mSv±0.17 mSv）。结论将心率控制在65次/min 以下,640层动态器官容积 CT 冠状动脉成像时既可以保证优质图像质量又可以降低有效射线剂量,65次/min≤心率≤122次/min时,图像质量降低,但仍能满足诊断要求。Objective To analyze retrospectively the impact of different heart rates on image quality and radiation dose of coronary angiography using 640-slice dynamic volume CT.Methods A total of 461 patients with suspected coronary artery disease or referred to health check underwent coronary angiography with 640-slice dynamic volume CT.Two groups were created according to their heart rates：Group A had heart rate 〈 65 beats per minute （n=337）and Group B had heart rate between 65 to 122 beats per minute （n=124）.Image quality was assessed by analyzing the 1 5 segments of the main coronary branches using 3-grade scale （grade I-good,grade Ⅱ-acceptable,grade Ⅲ-poor）.Effective radiation dose was also evaluated.Results Patients in both A group and B group performed successful CT coronary angiography with a total of 6 91 5 coronary segments.Among them,coronary segments that could be evaluated reliably accounted for 94.5% （6 535/6 91 5）while 5.5% （380/6 91 5）were too small （≤1.5 mm）to be assessed. For the image quality,Group A and Group B had grade I in 90.5% （305/337）vs 74.2% （92 /124）,grade Ⅱ in 9.5% （32/337）vs 21.0% （26 / 124）and grade Ⅲ in 0 % （0 / 337 ）vs 4.8% （6 / 124）,respectively.Image quality was significantly different be-tween Group A and Group B （P 〈0.001）.In addition,32 patients （9.5%）in Group A had slight cardiac motion artifacts but with-out affecting image quality,whereas 26 patients （21.0%）in Group B had higher degree of cardiac motion artifacts thus graded as grade Ⅱ.Stair-step artifacts were not found in all patients.The effective radiation dose was higher in Group B than in Group A by 32.05%（7.91±0.34 mSv vs 5.99±0.17 mSv）.Conclusion Coronary angiography using 640-slice dynamic volume CT can guarantee excellent image quality when heart rate 〈 65 beats per minute.Although the image quality would decrease in some extent it is still diagnostic when heart rate is between 65 to 122（include 65 and 122）beats per minute.

关 键 词：640层动态器官容积CT 冠状动脉成像 心率 图像质量 射线剂量 

分 类 号：R814.42[医药卫生—影像医学与核医学] R322.121[医药卫生—放射医学]