心率对64层螺旋CT冠状动脉成像质量的影响

Noninvasive coronary angiography with 64-slice spiral CT:effect of heart rate

目的 评价心率对64层螺旋CT冠状动脉成像质量的影响.方法 对260例行64层CT冠状动脉CTA检查的连续病例进行分析评价,心率为46～113次/min,平均（72.10±12.54）次/min.应用1～4级评分标准进行图像质量评分,统计检查成功率（评分2以上）和图像优良率（评分3以上）,比较心率为＜60次/min、60～69次/min、70～79次/min、80～89次/min和≥90次/min 时冠脉图像质量与心率的关系.同时分析不同心率下图像重建时相选择.统计分析心率与成像质量的关系以及不同心率时,冠脉检查成功率、显示优良率和重建心动周期时相的差异.结果 260名受检者,冠状动脉显示成功率为99.26%（2581/2600）,显示优良率为88.69%（2306/2600）.心率与成像质量呈负相关（r=-0.92）.心率＜70次/min与心率≥70次/min者在显示优良率方面存在显著性差异（χ^2=44.68,P＜0.01）.心率＜80次/min,重建时相以舒张中期（50%～75%）为主,心率≥80次/min,重建时相以收缩末期（25%～45%）为主（χ^2=98.88,P=0.000）.结论 心率与冠状动脉成像质量明显相关,64层螺旋CT在高心率下可以获得达诊断标准冠脉图像,心率在70次/min以下图像质量较高.

Objective To evaluate the effect of heart rate on the quality of coronary angiography performed by 64-slice spiral CT. Methods Two hundreds and sixty consecutive patients underwent CT coronary angiography （heart rate range, 46- 113/min, mean [72.10±12.54]/min）. Five groups were designed according to the heart rate （〈60, 60-69, 70-79, 80- 89 and 〉90/min）. Image quality of each segment was graded with a four-point scale from one （worst image quality） to four （best image quality）. Images scored between two and four were considered valuable for coronary artery assessment; those with a score of 3 or 4 were excellent images. The heart rate, image quality and reconstruction phase were evaluated. Results Two thousands five hundreds and eight-one segments diagnostic images were available from 2600 coronary segments （99.26%）, while 2306 （88. 69%） of them were excellent images. A significant negative correlation was observed between heart rate and image quality （r=-0.92）. Significant differences of excellent images were shown between heart rate lower and higher than 70/min（χ^2 = 44.68, P〈 0.01 ）. Reconstruction phase at mid-diastolic （ 50 % - 75% ） and end-systolic phase （25 %-45 %） yielded the best images when heart rates were lower and higher than 80/min, respectively （χ^2 = 98.88, P= 0. 000）. Conclusion Diagnostic coronary artery images can be obtained at high heart rates with 64-slice spiral CT scanners, but image quality was negatively correlated with heart rate, and excellent image can be achieved as heart rates less than 70/min.