320排容积CT冠状动脉成像低剂量扫描技术的临床应用

目的：评价与比较320排容积CT的前瞻性心电门控技术扫描和ECG管电流调制扫描技术的冠状动脉成像图像质量以及辐射剂量。方法：对临床拟诊为冠心病的97例患者，随机分成两组：①常规组（A组）53例，采用ECG管电流调制扫描技术；②低剂量组（B组）44例，采用前瞻性心电门控技术扫描。采用4分法主观评价冠状动脉可评估率，通过对比两组的升主动脉根部的平均强化CT值（SI）、噪声（SD）、信噪比（SNR）、对比信噪比（CNR）客观评价冠状动脉。采用Mann-WhitneyU检验比较两组冠状动脉可评估率，采用两独立样本t检验比较两组的辐射剂量。结果：A组平均有效辐射剂量为（8.66±3.67）mSv，B组平均有效辐射剂量为（3.99±2.42）mSv，两组比较差异有统计学意义（t=-7.503，P＜0.05）。A、B两组共1187段血管，A组中较为优秀（3分或4分）的血管段数占92.4%（599/648），B组占92.9%（501/539），A、B两组冠状动脉图像质量主观评分比较差异无统计学意义（Z=-0.480，P=0.631）。A、B两组的SI、SD、SNR、CNR分别为（433.4±82.5） HU、22.1±6.2、20.7±5.7、16.6±5.0和（436.1±94.7）HU、21.5±4.9、20.9±5.5、16.9±4.7，两组冠状动脉段图像质量从客观上比较差异无统计学意义（t=0.153、-0.522、0.240、0.311，均P＞0.05）。结论：320排容积CT冠状动脉成像采用低剂量技术可以减少54%的辐射剂量，又可保证图像质量。

Clinical application of low dose research for coronary CT angiography with 320-slice volume CT

tomography angiography （CCTA） received by prospective ECG-gated CTA mode with tube current modulated CFA mode on 320-slice volume CT.Methods： Ninety-seven patients with suspected coronary artery disease were randomly divided into two groups： 53 consecutive patients were performed CCTA with tube current modulated CFA mode （group A） and 44 patients with prospective electrocardiographic gating （group B）. Evaluating coro-nary artery by subjective and objective judgements, the image quality of CCTA were subjectively evaluated using a 4-point scale, while objectively evaluated by comparing mean intraluminal attenuation （SI）, noise （SD）, signal-to-noise ratio （SNR）, contrast-to-noise ratio （CNR） of the ascending aorta. The image quality of coronary artery between groups was compared by Mann-WhitneyU test, and the radiation dose between groups was compared byt test.Results： The average radiation dose was （8.66±3.67） mSv in group A and （3.99±2.42） mSv in group B, with signiifcant difference for A vs B （t=-7.503,P〈0.05）. Of 1187 coronary artery segments in group A and B, good image quality （score of 3 or 4） was achieved in 92.4% （599∕648） in group A, 92.9% （501/539） in group B, with no signiifcant difference for A vs B （Z=-0.480,P=0.631）. The values of SI, SD, SNR, CNR in group A were （433.4±82.5）HU, （22.1±6.2）, （20.7±5.7）, （16.6±5.0）, and the values of SI, SD, SNR, CNR in group B were （436.1±94.7） HU, （21.5±4.9）, （20.9±5.5）, （16.9±4.7）. There was no signiifcant difference of the image quality between group A and B objectively （P〉0.05）.Conclusion： 54% radiation dose of CCTA is reduced in 320-slice volume CT scan by using prospective ECG-gated CTA mode, moreover, the diagnostic quality of the image is also ensured.