不同对比剂浓度对能谱CT冠脉成像的影响

The Effect of Different Contrast Media Concentration on Spectral CT Coronary Angiography

目的:探讨能谱CT冠状动脉成像(CTCA)不同浓度对比剂对冠状动脉管腔内CT值、冠脉显示图像质量以及斑块局部显示质量。方法:51名怀疑或诊断为冠状动脉性心脏病的病人被分为A、B、C三组,每组17人;所有病人都用能谱CT进行CTCA检查,A组对比剂浓度为320mgI/ml,B组为350mgI/ml,C组为370mgI/ml。通过能谱后处理工作站分析每个病人冠脉显示的最佳对比噪声比(CNR),得到最佳单能量点(keV);分别在最佳单能量图像上的升主动脉根部、左主干以及右侧冠状动脉近段的三个不同水平及斑块局部放置感兴趣区(ROI),测量以上各位置管腔内平均CT值、图像噪声(SD)、信噪比(SNR)以及斑块局部显示质量(SNR、CNR),并对各主要冠脉节段图像质量进行评分。结果:51例患者共663个冠脉节段纳入图像质量评分,其中满足诊断要求者658段(99.2%),共检出不同斑块成分51处(A组20处,B组14处,C组17处),其中钙化22处(A组7处,B组6处,C组9处),非钙化19处(A组8处,B组6处,C组5处);与B、C组相比,A组的对比剂浓度分别降低了9%、14%;三组间最佳单能量点、最佳CNR、管腔CT值、SD、SNR、图像质量评分、斑块局部显示质量比较差异均无统计学意义(P>0.05)。结论:冠状动脉CT能谱成像时,应用320mgI/ml对比剂具有相对较低的浓度,并且不会降低冠脉管腔增强效果以及冠脉图像质量。

Purpose：To study the effect of different concentration of contrast agent on the CT values in coronary lumen and the image quality in spectral CT coronary angiography （CTCA）.Methods：Fiftyone patients diagnosed or suspected with coronary heart diseases （CAD） were divided into three groups with seventeen patients in each group.All of them were undergone spectral CTCA.The contrast agent concentration was 320mg/100ml for group A,350mg/100ml for group B and 370mg/100ml for group C.ROIs were respectively set at three different levels of aortic root,left main （LM） coronary artery and proximal right coronary artery （RCA） and plaques.The optimal contrast-noise-ratio （CNR） analysis software was used in spectral CT workstation to select the optimal energy for displaying the coronary artery.CT value and noise （SD） and signal to noise （SNR） of each ROI and SNR and CNR of every plaque was measured under the optimal energy.The scores of image quality of main coronary segments were recorded.Results：Fifty-one patients were successfully completed inspection.In 663 coronary segments,there were 658 segments meet the diagnostic requirements （99.2%）.There were 41 different compositions of plaques （20 in group A,14 in group B,17 in group C）,among which there were 22 calcified components （7 in group A,6 in group B,9 in group C） and 19 non-calcified components （8 in group A,6 in group B,5 in group C）.There was 9% and 14% contrast media dosage reduction between group A and group B,and between group A and group C,respectively.There was no significant difference of optimal Kev,CNR,luminal CT value,SD,SNR and the scores and the image quality of every plaque among there groups （P〉0.05）.Conclusion：It might not affect the enhancement in vessels and image quality with the reduced contrast concentration （320mgI/ml） in spectral CT coronary angiography（CTCA） under the optimal Kev.