门控心肌灌注异常与双源CT冠状动脉狭窄程度间的关系分析

Relationship Between Myocardial Perfusion Abnormality and Degree of Dual Source CT Coronary Artery Stenosis

目的通过分析潘生丁负荷门控心肌灌注显像（G-MPI）不同灌注异常程度与双源CT冠状动脉成像（DSCTCA）冠状动脉不同狭窄程度间的关系,评价DSCTCA预测患冠心病可能性为中-高度可能性病人心肌灌注异常程度的能力。方法115例患者一个月内行潘生丁负荷MPI和DSCTCA。心肌灌注异常的程度采用半定量分析分为：轻、中、重度放射性减低及放射性缺损。DSCTCA按照国际通用目测法将冠状动脉狭窄程度分为：狭窄〈50%、50%~69%、70%~99%及闭塞性病变。分析心肌灌注减低程度与不同程度冠状动脉狭窄间的关系。以MPI为参考标准,将DSCTCA预测心肌灌注减低的冠脉狭窄程度判定界值设为≥50%或≥70%,确定该方法的诊断效能。计数资料分析采用Mantel-Haenszelχ2、Pearsonχ2检验。结果冠状动脉狭窄〈50%、50%~69%、70%~99%及闭塞性病变中心肌灌注异常比例分别为55.6%（20/36）,71%（25/35）、81%（21/26）及83%（5/6）,随着冠状动脉狭窄程度增加心肌灌注减低发生率增加（χ2=28.16,P〈0.05）。冠脉狭窄判断界值为≥50%或≥70%时,DSCTCA预测心肌灌注减低的诊断敏感性、特异性、准确性、阳性预测值、阴性预测值分别为63.21%（67/106）或30.19%（32/106）（χ2=23.21,P〈0.05）、97.07%（232/239）或99.16%（237/239）（χ2=2.83,P〉0.05）、86.67%（299/345）或77.97%（269/345）（χ2=10.87,P〈0.05）、90.54%（67/74）或94.12%（32/34）（χ2=0.39,P〉0.05）、85.61%（232/271）或76.21%（237/311）（χ2=8.18,P〈0.05）。结论随着冠状动脉狭窄程度增加心肌灌注减低缺损发生率及程度均呈增高趋势。在冠心病中、高度可能性的患者中,以冠脉狭窄界值≥70%时DSCTCA预测心肌缺血的特异性和阳性预测值较冠脉狭窄界值为≥50%为佳。

Objective Through comparative analysis between the dipyridamole stress gated myocardial perfusion imaging（G-MPI） defect and severity of coronary stenosis on dual source CT coronary angiography（ DSCTCA）, to evaluate the diagnostic ability of dual source CTCA in predicting myocardial perfusion abnormality degree in patients with a medium or high possibility of CAD. Methods One hundred and fifteen patients who underwent dipyridamole stress 99Tcm-MIBI MPI and DSCTCA in the same period were involved in the study. The extent of myocardial perfusion abnormalities by semi quantitative analysis was divided into light, moderate, severe radioactive reduce and radioactive defect groups. According to the severity of coronary artery stenosis judged by international general visual method evaluation of the vessel diameter, the patients were divided into four groups 〈 50%, 50 ~ 69%, 70% - 99% and total occlusion. The relationship between myocardial perfusion defects and the degree of coronary artery stenosis was analyzed. Taking MPI as the standard reference, the cut-off of stenotic severity for predicting myocardial perfusion reduced was set to I〉50% or~〉70%. Mantel-Haenszel Chi- square test were used to compare ordinal variables. The diagnostic performance of DSCTCA were calculated and analyzed by Pearson Chi-square test. Results The myocardial perfusion abnormal rates in luminal stenosis 〈 50%, 50 -69%, 70% ~99% and total occlusion groups were 55.6%, 71%, 81% and 83%, respectively. The degree of coronary artery stenosis increased with myocardial perfusion defect occurrence rate increased （X2 =28.16, P 〈 0.05）. When the cut-off was designated as ≥50% and ≥70% respectively, the diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive values for DSCTCA predicting myocardial perfusion reduce were 63.21% or 30.19%, 97.07% or 99.16%, 86.67% or 77.97%, 90.54% or 94.12%, 85.61% or 76.21%, respectively. Conclusion The prevalence and degree of myocardial perfusion defects showed an increased trend with greater coronary artery stenosis. When the cut-off value is set at I〉70%, the specificity and positive predictive value of DSCTCA predict perfusion defects in patients with medium and high probability of CAD is significantly improved.