超低剂量宽探测器CT扫描模式在冠状动脉CTA检查患者中的应用价值

The application value of ultra-low-dose wide-detector CT scan mode in patients undergoing coronary CTA

目的探究超低剂量宽探测器CT扫描模式对冠状动脉CT血管成像(CT angiography,CTA)检查患者辐射剂量、图像优良率的影响及对冠状动脉狭窄的诊断价值。方法选取我院疑似冠状动脉粥样硬化性心脏病(Coronary heart disease,CHD)患者85例作为研究对象,均行东芝320排螺旋CT检查,常规组采取100 kV管电压检查,超低剂量组采取70 kV管电压检查。比较两组检查过程中平均心率、辐射剂量[CT容积剂量指数(CT dose index-volume,CTDIvol)、剂量长度乘积(dose-length product,DLP)、有效剂量(effective dose,ED)]、图像客观评价参数[最佳信噪比(signal-to-noise ratio,SNR)、噪声对比度(contrast-to-noise ratio,CNR)]、图像质量评分、图像优良率,并以数字减影血管造影(digital subtraction angiography,DSA)为金标准,评价超低剂量检查冠状动脉狭窄程度与DSA的一致性,分析其对冠状动脉狭窄程度≥50%(中度及以上)的诊断价值。结果超低剂量组CTDIvol、DLP、ED低于常规组,SNR、CNR高于常规组,差异有统计学意义(P<0.05)。经2名资深影像诊断医师以双盲法对图像质量的评估,两组图像质量评分、图像优良率差异比较,差异无统计学意义(P>0.05);2名医师对图像质量评估的一致性较高(Kappa值=0.772)。以DSA检查为金标准,超低剂量宽探测器CT扫描模式与DSA诊断冠状动脉狭窄程度的一致性较高(Kappa值=0.943)。以DSA为金标准,超低剂量宽探测器CT扫描模式诊断冠状动脉狭窄程度≥50%(中度及以上)的AUC为0.939,敏感度、特异度、准确率分别为88.89%、98.87%、98.16%。结论超低剂量宽探测器CT扫描模式具有图像客观评价较高、对图像优良率影响小等优势,有助于减少冠状动脉CTA检查患者辐射剂量,指导临床评估冠状动脉狭窄程度,实施个性化治疗方案。

Objective To explore the effect of ultra-low-dose wide-detector CT scanning mode on the radiation dose and excellent and good rate of image by coronary CT angiography(CTA)and its diagnostic value for coronary stenosis.Methods A total of 85 patients with suspected coronary heart disease(CHD)were selected as the research subjects,all of whom underwent Toshiba′s 320-slice spiral CT examination.The conventional group was tested with 100 kV tube voltage,and the ultra-low-dose group was tested with 70 kV tube voltage.The mean heart rate during the examination and radiation dose[CT dose index-volume(CTDIvol),dose-length product(DLP),effective dose(ED)],objective evaluation parameters of image[optimal signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)],image quality score,the excellent and good rate of image were compared between two groups.Digital subtraction angiography(DSA)was used as the gold standard,the consistency of the degree of coronary artery stenosis in ultra-low dose examination with DSA was evaluated,and its diagnostic value for coronary artery stenosis degree≥50%(moderate and above)was analyzed.Results CTDIvol,DLP,and ED in the ultra-low-dose group were lower than those in the conventional group,while SNR and CNR were higher than those in the conventional group,with significant difference(P<0.05).After two senior diagnostic imaging physicians assessed the image quality with a double-blind method,there was no statistically significant difference between two groups in the image quality score and the excellent and good rate of image(P>0.05).The agreement of the two doctors on the image quality assessment was high(Kappa value=0.772).With DSA examination as the gold standard,the ultra-low-dose wide-detector CT scan mode was consistent with DSA in the diagnosis of coronary stenosis(Kappa value=0.943).With DSA as the gold standard,the AUC of ultra-low-dose wide-detector CT scan mode in the diagnosis of coronary stenosis≥50%(moderate and above)was 0.939.The sensitivity,specificity,and accuracy were 88.89%,98.87%,and 98.16%,respectively.Conclusion The ultra-low-dose wide-detector CT scan mode has the advantages of higher objective evaluation of images and less impact on the excellent and good rate of image quality.It is helpful to reduce the radiation dose of patients undergoing coronary CTA examination,guide clinical assessment of coronary stenosis degree,and implement personalized treatment plan.