Correlations Analysis of the Entrance Surface Dose according to the BMI at Computed Tomography and Angiography in Cardiovascular Examination

Abstract

Background/Objectives: The purpose of this study was to investigate the correlation between the entrance surface dose (ESD) and the patient’s body mass index (BMI) in coronary angiography (CAG) of the cardiovascular center and coronary computed tomography angiography (CCTA). Methods/Statistical analysis: This study was conducted on 300 patients (CAG 100 persons; CTA 200 persons), who underwent CAG and CCTA in this hospital from December 2012 to March 2017. To analyze the ESD, the CTDIvol value was obtained from CCTA, and the air kerma value was obtained from CAG for retrospective analysis. CCTA was conducted using the prospective ECG gating technique (PGT) and the retrospective ECG gating technique (RGT). Findings: In the cardiovascular lesion examinations, PGT showed a higher ESD compared to RGT, but the difference was not statistically significant (403.8±118.7 vs. 384.7±117.4, P=0.553). In the correlation between BMI and ESD, there were statistically significant differences among the three groups (PGT, RGT, and CAG) (p<0.05). In the linear relationship examined with a scatter plot, the dose in CAG increased with the increase in BMI (R2=0.144, p<0.001), but the doses in PGT (R2=0.04, p<0.05) and RGT (R2=0.144, p<0.05) decreased with the increase in BMI. Improvements/Applications: Although the dose of CAG tended to increase with the increase in the patient’s BMI, the dose of CCTA tended to decrease inversely. Therefore, BMI may be used as the criterion for the selection of an appropriate examination considering the exposure dose.