【摘要】 【目的】探讨前瞻性心电门控螺旋扫描联合低管电压、低对比剂注射速度及剂量技术在全主动脉及冠状动脉一站式CT成像中的应用。【方法】收集心率≤75次/min且心律齐的临床可疑主动脉病变或主动脉术后复查CT的患者60例,将其随机分为两组,每组各30例。两组均采用320排CT前瞻性心电门控螺旋模式扫描,除实验组(G1)采用管电压80 kV、对比剂注射速率3 m/s及对比剂容量0.65 mL/kg扫描方案,常规组(G2)组采用管电压120 kV、对比剂注射速率4 m/s及对比剂容量1.2 mL/kg扫描方案扫描外,其他扫描及重建参数相同。测量主动脉及冠状动脉各节段的CT值及其相应平面脂肪组织的CT值及标准差,计算信噪比(SNR)及对比噪声比(CNR),由两名高年资放射医师对三维后处理图像质量进行主观评分,并记录对比剂使用剂量、辐射剂量。比较和分析两组的客观图像质量(血管CT值、噪声、SNR及CNR)、主观图像质量、辐射剂量及对比剂使用剂量等指标。【结果】G1组检出主动脉异常率83.33%(25/30),正常率16.67%(5/30);冠状动脉异常率43.33%(13/30),正常率56.67%(17/30)。G2组检出主动脉异常率86.67%(26/30),正常率13.33%(4/30);冠状动脉异常率53.33%(16/30),正常率46.67%(14/30)。客观图像质量指标中,除升主动脉、降主动脉、腹主动脉、肠系膜上动脉、双侧肾动脉、左冠状动脉主干、前降支、回旋支、右冠状动脉SNR及腹主动脉、肠系膜上动脉、双侧肾动脉、前降支、回旋支CNR无统计学差异外,其余的指标均有显著的统计学差异。G1组的辐射剂量与对比剂使用剂量明显低于G2组(P<0.05)。两组的血管三维后处理图像主观质量评分无统计学差异(P>0.05)。【结论】在全主动脉及冠状动脉一站式CT扫描中,运用前瞻性心电门控螺旋扫描联合低管电压及低流速、低对比剂剂量技术,能够在无明显降低图像质量的前提下降低患者的辐射剂量和对比剂使用剂量。更多还原

【Abstract】 【Objective】To investigate the clinical value of using prospective ECG-gating Helical protocol in whole aorta and coronary arteries CT angiography combined with low tube voltage,low contrast medium injection rate and dose technology.【Methods】A total of 60 patients(heart rate≤ 75 bpm and normal heart rhythm)with suspected aortic disease or post-operation were randomly divided into 2 groups:G1(n = 30;tube voltage:80 kV;contrast medium injection rate:3 mL/s;contrast medium dose:0.65 mL/kg)and G2(n = 30;tube voltage:120 kV;contrast medium injection rate:4 mL/s;contrast medium dose:1.2 mL/kg). The two groups underwent aorta angiography with prospective ECG-gating Helical protocol by using 320-detector CT. The mean CT values and standard deviation of aorta,coronaries and adjacent adipose tissue were measured,signal to noise ratio(signal-to-noise ratio,SNR)and contrast to noise ratio(contrast-to-noise ratio,CNR)were calculated. The subjective quality scoring of 3-d post-processing images were evaluated independently by 2 senior radiologists. The mean CT values and standard deviation of aorta,coronaries and adipose tissue,SNR,CNR,subjective quality scoring,contrast medium dose and radiation dose were compared and analyzed.【Results】The abnormal and normal rate of aorta in two groups were 83.33%(25/30),16.67%(5/30)and 86.67%(26/30),13.33%(4/30);while the abnormal and normal rate of coronary arteries in two groups were 43.33%(13/30),56.67%(17/30)and 53.33%(16/30),46.67%(14/30). SNR values of ascending aorta,descending aorta,abdominal aorta,superior mesenteric artery,bilateral renal artery,left main coronary artery,left anterior descending branch,left circumflex branch,right coronary artery and CNR values of abdominal aorta,superior mesenteric artery,bilateral renal artery,left anterior descending branch,left circumflex branch had no statistical significance,while the other indicators were significant differences between the two groups. The radiation dose and the contrast medium dose of G1 was significantly lower than G2(P < 0.05). There was no difference in the subjective image quality of 3D post-processing images between the two groups(P > 0.05).【Conclusions】Using prospective ECG-gating Helical protocol in whole aorta and coronary arteries CT angiography combined with low tube voltage,low contrast medium injection rate and low contrast medium dose technology can help to reduce radiation and contrast medium dose without impacting on the imaging quality satisfactorily.更多还原