舒张期冠状动脉CTA管腔内密度衰减率预测心肌桥收缩压迫程度

Percentage of attenuation drop of intra-mural coronary segment at diastolic phase coronary CTA in prediction of significant systolic compression of myocardial bridge

目的探讨舒张期冠状动脉CT血管成像(CCTA)参数壁冠状动脉管腔内密度衰减率预测心肌桥(MB)收缩压迫程度的价值。方法测量135例MB患者MB段以及MB近段冠状动脉管腔内平均CT值,计算壁冠状动脉管腔内密度衰减率(%)=(MB近端CT值-MB段CT值)/MB近端CT值×100%。以MB段管腔压迫致狭窄程度≥50%为显著收缩压迫,分析壁冠状动脉管腔内密度衰减率、MB长度、MB深度预测MB收缩压迫的效能。结果壁冠状动脉管腔内密度衰减率、MB长度在MB伴显著收缩压迫、MB伴轻度收缩压迫、MB不伴收缩压迫组患者中的差异均有统计学意义(P均<0.05)。ROC曲线显示密度衰减率的最佳临界值为15%,曲线下面积为0.75[95%CI(0.67,0.82),P<0.01],其诊断MB伴显著显著收缩压迫的准确率为73.3%。结论舒张期CT管腔内密度衰减率与MB收缩压迫程度有关,可通过该参数间接判断MB是否具有显著收缩压迫。

Objective To explore the diagnostic value of the percentage of attenuation drop measured by diastolic phase coronary CTA（CCTA）in identifying significant dynamic compression of myocardial bridge（MB）.Methods Totally 135 patients with MB confirmed by CCTA were enrolled.The CT value of MB segment and proximal MB segment was measureed respectively.Attenuation of mural coronary artery（%）=（CT value of proximal MB segment-CT value of MB segment）/CT value of MB segment×100%.Systolic compression≥50% was considered significant.The percentage of attenuation drop of MB vessel,length and depth of MB were measured and correlated with the presence and degree of dynamic compression.Results Attenuation drop of mural coronary artery（%）,length of MB in MB patients with significant systolic compression,slight systolic compression and without systolic compression had significant statistical differences（all P〈0.05）.ROC curve showed the percentage of attenuation had the best accuracy of 73.3% in diagnosis of MB with significant systolic compression with the cutoff value of 15% and the area under the curve（AUC）of 0.75（95% CI[0.67,0.82],P〈0.01）.Conclusion Attenuation drop of MB segment has relationship with the extent of dynamic compression of MB and it has value to identify significant dynamic compression of MB.