不同扫描延迟技术在大螺距冠状动脉CT血管成像中的对比研究

Comparative study of different scanning delay techniquesin high pitch coronary artery CT angiography

目的:比较2种扫描延迟技术在大螺距冠状动脉CT血管成像(CCTA)中运用的可行性。方法:前瞻性收集临床疑似冠心病行CCTA检查的心率≤60次/分病人58例,随机分为团注跟踪组31例和测试团注组27例。分别在主动脉根部、左主干、左前降支近段、左回旋支近段、右冠状动脉近段、肺动脉、左心房和左心室选取感兴趣区,测量CT值和噪声,计算信噪比、对比噪声比、左房室比、左室肺动脉比和主肺动脉比,评估2组图像质量,比较2组客观和主观评价指标差异。结果:2组各目标血管强化CT值、信噪比和对比噪声比差异均无统计学意义(P>0.05),团注跟踪组肺动脉CT值、左房室比、左室肺动脉比和主肺动脉比均明显低于测试团注组(P<0.01)。2组主观图像质量评分差异无统计学意义(P>0.05)。团注跟踪组CT剂量指数、剂量长度乘积、有效辐射剂量、注射流率和对比剂量均低于测试团注组(P<0.05~P<0.01)。结论:大螺距CCTA采用团注跟踪技术,可提高血管强化CT值并能降低辐射剂量和对比剂用量。

Objective:To compare the feasibility of two scanning delay techniques in high-pitch coronary CT angiography(CCTA).Methods:A total of 58 patients suspected with coronary heart disease detected by CCTA(heart rate≤60 beats/min)were prospectively collected,and randomly divided into the Bolus-tracking group(31 cases)and Test-bolus group(27 cases).The CT values and noise in the interest areas of aortic root,left main trunk,left anterior descending branch,left circumflex branch,right coronary artery,pulmonary artery,left atrium and left ventricle were measured.The CT values and noise were measured,the signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR),left atrioventricular ratio,left ventricular pulmonary artery ratio and principal pulmonary artery ratio were calculated,the image quality in two groups were evaluated,and the differences between objective and subjective evaluation indexes were compared between two groups.Results:The differences of the enhanced CT values,SNR and CNR of target vessels were not statistically significant(P>0.05),and the CT value of pulmonary artery,left atrioventricular ratio,left ventricular pulmonary artery ratio and principal pulmonary artery ratio in Bolus-tracking group were significantly lower than those in Test-bolus group(P<0.01).There was no statistical significance in the subjective image quality scores between two groups(P>0.05).The CT dose index,dose length product,effective radiation dose,injection flow rate and contrast dose in the Bolus-tracking group were significantly lower than those in Test-bolus group(P<0.05 to P<0.01).Conclusions:The high-pitch CCTA with Bolus-tracking method can increase the value of vascular enhanced CT and reduce the dose of radiation and contrast agent.