不同体质量指数患者冠状动脉CT血管成像扫描模式的优化选择

Optimal selection of coronary artery CT angiography scanning mode in patients with different body mass indices

目的探讨体质量指数(BMI)不同的患者冠状动脉CT血管成像(CCTA)扫描模式的优选方案。方法前瞻性研究。选取2022年4—8月淮北市人民医院影像科行CCTA检查的心前区不适患者180例,其中男93例、女87例,年龄26~82(55.4±11.5)岁,体质量指数(BMI)≥18.5 kg/m^(2)。180例中,18.5 kg/m^(2)≤BMI<28.0 kg/m^(2)者和BMI≥28.0 kg/m^(2)者各90例,分别纳入对照组与观察组,采用随机法分别分成A1、B1、C1亚组和A2、B2、C2亚组,每个亚组30例。其中A1、A2组采用常规管电压、管电流扫描模式,B1、B2组采用低管电压、正常管电流扫描模式,C1、C2组采用低管电压、高管电流扫描模式,进行CCTA扫描,以及轴位多平面重组(MPR)、曲面重建(CPR)和薄层最大密度投影(MIP)重组。采用冠状动脉分段评分法对图像质量进行主观评价;测量升主动脉根部的CT值和图像噪声(SD),计算并比较各组的图像信噪比(SNR),以及左冠状动脉主干、各分支近段的对比噪声比(CNR)等定量指标,对图像质量进行客观评价;计算并比较各组患者有效辐射剂量(ED)。结果患者年龄、性别、心率等基线资料在对照组与观察组2组间比较、组内3个亚组间比较,以及组内3个亚组间BMI比较,差异均无统计学意义(P值均>0.05)。A1、B1、C1组冠状动脉分段评分比较差异无统计学意义(H=1.35,P=0.510);A2组冠状动脉分段评分高于B2、C2组,差异均有统计学意义(P值均<0.05)。左冠状动脉主干、各分支近段的CT值比较,B1、C1组高于A1组,B2、C2组高于A2组,差异均有统计学意义(P值均<0.001)。主动脉根部SNR值,以及左冠状动脉主干、各分支近段的CNR值,在A1、B1、C13组间和A2、B2、C23组间分别进行比较,差异均无统计学意义(P值均>0.05)。B1、C1组ED值分别为(10.27±0.61)mSv、(11.65±0.96)mSv,均低于A1组的(17.31±1.27)mSv;B2、C2组ED值分别为(10.27±0.52)mSv、(11.66±0.87)mSv,均低于A2组的(17.05±0.91)mSv,差异均有统计学意义(P值均<0.05)。结论在CCTA检查时,对于18.5 kg/m^(2)≤BMI<28.0 kg/m^(2)的患者优选低管电压扫描模式,而对于BMI≥28.0 kg/m^(2)的患者则可适当增加管电压。

Objective This study aimed to explore the optimal scheme of coronary CT angiography(CCTA)scanning mode in patients with different body mass index(BMI).Methods A prospective study was conducted.A total of 180 patients with precordiac discomfort underwent CCTA examination in the Department of Medical Imaging of the Directly Affiliated Huaibei People's Hospital of Bengbu Medical College from April 2022 to August 2022,including 93 males and 87 females aged 26-82(55.4±11.5)years and with BMI≥18.5 kg/m².Among the 180 cases,90 cases with 18.5 kg/m²≤BMI<28.0 kg/m²and 90 cases with BMI≥28.0 kg/m²were included in the control and observation groups,respectively.They were further divided into A1-C1 subgroups and A2-C2 subgroups by simple random method,with 30 cases in each subgroup.Among them,the A1 and A2 groups adopted conventional tube voltage and tube current scanning mode,the B1 and B2 groups adopted low tube voltage and normal tube current scanning mode,and the C1 and C2 groups adopted low tube voltage and top current scanning mode to carry out CCTA scanning.Axial multiplanar reformatting(MPR),curved plannar reformatting(CPR),and thin layer maximal intensity projection(MIP)were also conducted.Image quality was evaluated subjectively by coronary artery segmental scoring.The CT value and image noise of the ascending aorta root were measured,and the image signal to noise ratio(SNR)of each group was calculated and compared.Moreover,the contrast to noise ratio(CNR)of the main trunk and branches of the left coronary artery were compared to evaluate the image quality Objective ly.Furthermore,the effective dose(ED)was calculated and compared in each group.Results No significant differences in age,gender,heart rate,and other baseline data was found between the control group and the observation group and among the three subgroups in the two groups,and BMI among three subgroups in the two groups(all P values>0.05).No significant difference was observed in the coronary artery segmentation scores among the A1-C1 groups(H=1.35,P=0.510).The coronary artery segmentation score in A2 group was higher than that in B2 and C2 groups,and the differences were statistically significant(all P values<0.05).The CT values of the left main coronary artery and its branches were higher in the B1 and C1 groups than in the A1 group,and higher in the B2 and C2 groups than in the A2 group,with statistical significance(all P values<0.001).The SNR values of aortic root and the CNR values of the left main coronary artery and proximal branches were compared among the A1-C1 groups and the A2-C2 groups,respectively,with no statistical significance(all P values>0.05).The ED values of the B1 and C1 groups were(10.27±0.61)and(11.65±0.96)mSv,respectively,which were lower than those of the A1 group at(17.31±1.27)mSv.The ED values of the B2 and C2 groups were(10.27±0.52)and(11.66±0.87)mSv,respectively,which were lower than those of the A2 group(17.05±0.91)mSv,and the differences were statistically significant(all P values<0.05).Conclusion For patients with 18.5 kg/m²≤BMI<28.0 kg/m²,low tube voltage scanning mode is preferred,whereas for patients with BMI≥28.0 kg/m²,the tube voltage could be appropriately increased.