Effects of combining multiple dose reduction techniques on coronary computed tomography angiography

Figure 1 For group A₁, the isocentric scan was performed with the patient in supine position and their body shifted to the right. A: Conventional position; B: Isocentric scanning.

Figure 2 Subjective imaging quality scores. A: Excellent imaging quality (IQ) (score = 5) with sharp, smooth contours of the vascular wall and no streaking or radiating artifacts; B: Good IQ (score = 4) with slight irregularities on the contour and few streaks or radiating artifacts; C: Fair IQ (score = 3) with blurred and irregular contours of the vascular wall and numerous streaks or radiating artifacts; D: Poor IQ (score = 2) with deformation of the vascular wall and various artifacts; E: Very poor IQ (score = 1) with obvious deformation of the vascular wall and extensive artifacts. Images with IQ scores within 3-5 satisfy the requirements for the diagnostic assessment.

Figure 3 A 69-year-old female patient in group A₁. For the multislice computed tomographic angiography, the image quality score was 5 (excellent) for left anterior descending artery segments 5-8. A and B: Volume rendering; C: Curved planar reformation. Body mass index: 26.40; Effective dose: 1.18 mSv; Noise: 18.80; Signal-to-noise ratio: 52.68; Contrast signal-to-noise ratio: 42.89.

Figure 4 A 64-year-old female patient in group A₁. For the multislice computed tomographic angiography, the image quality score was 5 (excellent) for left anterior descending artery segments 5-8. A and B: Volume rendering; C: Curved planar reformation. Body mass index: 26.40; Effective dose: 1.83 mSv; Noise: 22.50; Signal-to-noise ratio: 43.90; Contrast signal-to-noise ratio: 30.40.

Figure 5 A 68-year-old female patient in group A₂. For the multislice computed tomographic angiography, the image quality score was 5 (excellent) for left anterior descending artery segments 5-8. A and B: Volume rendering; C: Curved planar reformation. Body mass index: 22.38; Effective dose: 3.33 mSv; Noise: 13.10; Signal-to-noise ratio: 74.69; Contrast signal-to-noise ratio: 58.85.