基于碘流率注射方案实现冠状动脉CT血管成像质量均一化的可行性研究

Feasibility study on iodine flow rate injection protocol to achieve consistent image quality in coronary CT angiography

目的探讨在冠状动脉CT血管成像(CCTA)检查中,参考指南推荐的不同体重患者碘流率注射方案,获得优质图像和图像质量均一化的可行性。方法2017年10月至2018年1月前瞻性入选阜外医院159例疑诊冠心病行CCTA检查的连续患者,根据体重划分为5组:≤60、61~70、71~80、81~90、>90 kg,其中前3组应用100 kV管电压扫描,后两组应用120 kV管电压扫描,均使用含碘370 mg/ml对比剂,每组分别应用1.0、1.2、1.4、2.0和2.2 mg/s的注射碘流率。测量主动脉根部、前降支近段以及右冠状动脉远段的CT值和噪声(SD),以及前降支近段和右冠状动脉远段的对比度噪声比(CNR)和信噪比(SNR),所有参数均采用Shapiro-Wilk检验分析数据正态性,符合正态分布的参数间比较采用单因素方差分析。结果5组患者的主动脉根部CT值分别为(368.7±32.4)、(356.7±30.8)、(366.0±34.6)、(360.7±25.0)和(352.3±28.4)HU,差异无统计学意义(F=1.541,P=0.19);前降支近段CT值及右冠状动脉远段CT值组间差异也均无统计学意义(P>0.05)。5组患者间前降支近段、右冠状动脉远段的SD、CNR及SNR差异也均无统计学意义(P>0.05);各组图像质量主观评分分别为(3.9±0.2)、(3.8±0.3)、(3.9±0.2)、(3.9±0.3)、(4.0±0.2)分,差异无统计学意义(F=1.202,P=0.36)。结论对于不同体重患者,参考指南的碘流率对比剂注射方案行CCTA检查,可在保证图像质量的前提下实现血管强化程度的均一性,从而有可能真正实现个体化和规范化的检查效果。

Objective To investigate the feasibility of using a specific iodine delivery rate in coronary computed tomography angiography(CCTA) to obtain high and uniform image quality in patients with different body weight, according to the latest guideline of contrast medium injection protocol. MethodsA total of 159 consecutive patients who had undergone CCTA for ruling out coronary heart disease were prospectively enrolled and divided into five subgroups according to body weight:≤60, 60-70, 70-80, 80-90,>90 kg, the former three subgroups were scanned using 100 kV tube voltage, the latter two subgroups were scanned using 120 kV tube voltage. All patients were injected with the contrast agent of which concentration was 370 mgI/ml, using a specific iodine delivery rate (1.0, 1.2, 1.4, 2.0 and 2.2 mgI/s, respectively). The Shapiro-Wilk test was performed to assess the normality of data distribution, including the CT attenuations in the aortic root, proximal left anterior descending artery, the distal segments of the right coronary artery, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and subjective image quality scores. Parameters accorded with normal distribution were compared by analysis of variance (ANOVA). ResultsThere were no statistical differences in the CT attenuations (HU) of the aortic root (368.7±32.4, 356.7±30.8, 366.0±34.6, 360.7±25.0, 352.3±28.4, respectively, F=1.541, P=0.19);This was also true for the proximal segments of the left anterior descending arteries and the distal segments of right coronary arteries (all P>0.05). Also, there were no statistical differences of SD, CNR and SNR in neither the proximal part of the left anterior descending coronary arteries nor the distal right coronary arteries in these five groups (all P>0.05);There were no statistical differences in subjective scores of each group (3.91±0.23, 3.83±0.30, 3.94±0.21, 3.90±0.27, 3.95±0.20, respectively, F=1.202, P=0.36). ConclusionFor patients undergoing CCTA with different body weights, using guideline introduced iodine delivery rate injection protocol of contrast medium could achieve consistent vascular enhancement with satisfied image quality. This protocol is promising to make personalized and standardized CCTA possibly.