Table 1.
Demographic data for the 30 subjects in Group A and Group B.
Fig 1.
Comparison of radiation dose, computed tomography attenuation, and image noise between Group A and Group B. (a) The mean radiation dose in Group A is lower (sub-mSv levels) than that of Group B (p < 0.001). (b) The mean computed tomography attenuation is higher in Group A than in Group B (p < 0.001). (c) The image noise is not statistically different between Group A and B (p = 0.702).
Fig 2.
Differences in noise in coronary computed tomographic angiography images at the aortic root between Group A and Group B.
The non-inferiority of the image noise with the 80 kVp scan protocol was confirmed, because the upper limit of the two-sided 95% confidence interval (CI) of the mean image noise difference was smaller than the pre-defined non-inferiority margin of 5.0 (mean difference: -0.57, 95% CI: -3.56–2.41).
Table 2.
Quantitative analysis of coronary computed tomographic angiography image quality in Group A compared to Group B.
Fig 3.
Representative coronary computed tomographic angiography (CCTA) images in Group A and Group B.
Curved multi-planar images of the right coronary artery in Group A (a) and Group B (b). Note the substantial reduction in noise and the significantly increased vessel attenuation in (a) compared to (b). (a) A 48-year-old woman underwent CCTA using step-and-shoot axial scanning, 80 kVp tube voltage, and 150 mAs tube current for coronary disease screening. She was 160 cm tall and weighed 49 kg (body mass index: 19.1 kg/m2). Her mean heart rate during CCTA was 54 bpm, and the effective radiation dose was 0.63 mSv. The mean attenuation of the ascending aorta was 536.1 HU. The image noise on CCTA was 26.7. The overall image quality was 3.8. (b) A 53-year-old woman underwent CCTA using step-and-shoot axial scanning, 100 kVp tube voltage, and 150 mAs tube current for coronary disease screening. She was 166 cm tall and weighed 52 kg (body mass index: 18.9 kg/m2). Her mean heart rate during CCTA was 56 bpm, and the effective radiation dose was 1.33 mSv. The mean attenuation of the ascending aorta was 374 HU. The image noise on CCTA was 31.7. The overall image quality was 3.5.
Table 3.
Qualitative analysis of the images produced for Group A versus B.