心率波动对冠状动脉运动及64层螺旋CT冠状动脉成像质量的影响

Influence of Fluctuation of Heart Rate on Coronary Movement and Image Quality of 64-slice Spiral CT Coronary Angiography

目的探讨心率波动对冠状动脉运动及64层螺旋CT冠状动脉成像质量的影响。方法选取本院临床申请多层螺旋CT冠状动脉成像(MSCTCA)且同意参加试验者34例为试验组,根据两次扫描心率变化分为三组,A组:≤5次/minBMP,B组:6～10次/minBMP,C组:>10次/minBMP。分别测量心脏收缩末期和舒张末期右冠状动脉和左前降支间的距离,计算两次扫描的距离变化差。回顾性收集同期64SCTCA资料完整者137例为临床组,根据心率波动程度分成三组:Ⅰ组:0～2次/minBMP,Ⅱ组:3～6次/minBMP,Ⅲ组:>7次/minBMP。按5分法评价不同心率波动情况下的图像质量。结果试验组两次扫描右冠状动脉与左前降支的间距差以舒展期变化较大,同收缩期比较差异有统计学意义(P<0.05);心率变化越大,距离的变化值也越大(P<0.05)。临床组137例患者共有83.2%冠状动脉图像质量可满足诊断要求。不同心率波动组间冠状动脉图像质量有显著差异,心率变化越小图像质量越好(P<0.05)。结论心率波动时数据匹配错误是导致图像质量降低的根本因素,稳定心率有助于提高图像质量。

Objective To evaluate the influence of fluctuation of heart rate on coronary movement and image quality of coronary CT angiography. Methods According to the fluctuation of heart rate, 34 volunteers were classified into 3 groups： its fluctuation of mean heart rate ≤5 beat per minute （BMP） for group A, 6 - 10 BMP for group B, and 〉 10BMP f·group C. The distance between the right coronary and the left anterior descending branch in the late systole and diastole were measured, respectively. The distance variability under two different heart rate conditions were calculated. Meanwhile, 137patients were also classified into 3 groups： the fluctuation of the heart rate 42 BMP for group Ⅰ; 3 -6 BMP for group Ⅱ, and 〉 10BMP for group Ⅲ. The image quality of MSCTCA was scored 5 grades by coronary motion artifact. Results Compared with two images scanning on defferent heart rate, the variability of the distance between the right coronary and the left anterior descending branch in the late diastole was significantly obvious than that in the late systole. Diagnostic image quality was attained in 456 of 548 coronary arteries at the best reconstruction interval in 137 patients. There was a significant correlation between the fluctuation of heart rate and image quality. Conclusion Large fluctuation of heart rate will cause serious motion artifacts in the images caused by mismatches between the concurrent sectors used in the multisector reconstruction process. Reducing fluctuation of heart rate is beneficial for improving the image quality.