Supplemental Digital Content 1. HU measurements with BMI as a covariate
370 mg I/ml 320 mg I/ml 270 mg I/ml
Average HU (HU) 444.3
(421.8, 466.9) 532.7
(509.4, 556.0) 488.5
(465.9, 511.1)
Noise 32.9
(30.6, 35.2)
46.9 (445, 49.3)
45.2 (42.9, 47.6)
SNR 14.3
(13.5, 15.0) 11.9
(11.1, 12.7) 11.2
(10.5, 12.0) Pericardial fat (HU) -95.4
(-101.1, -89.7)
-99.9 (-105.8, -94.0)
-102.2 (-107.9, -96.5) Contrast
enhancement (HU) 539.7
(516.3, 563.2) 632.6
(608.4, 656.7) 590.7 (567.2, 614.2)
CNR 17.4
(16.5, 18.2)
14.2 (13.3, 15.1)
13.6 (12.7, 14.5) Data are presented as mean (95% confidence interval).
BMI, body mass index; CNR, contrast-to-noise ratio; HU, Hounsfield unit; SNR, signal-to- noise ratio
Supplemental Digital Content 2. Comparative analysis of HU measurements with BMI as a covariate
Overall 370 vs 320 mg I/ml 370 vs 270 mg I/ml 320 vs 270 mg I/ml P-
value
Difference (95% CI)
p- value
Difference (95% CI)
p- value
Difference (95% CI)
p- value Average HU <.001 88.4
(55.9, 120.8)
<.001 44.2 (12.2,
76.2)
0.007 -44.2 (-76.6, -11.7)
0.008
Noise <.001 14.0
(10.7, <.001 12.4
(9.0, 15.7) <.001 -1.7
(-5.0, 0.334
17.4) 1.7)
SNR <.001
-2.4 (-3.4,
-1.3) <.001
-3.0 (-4.1,
-2.0)
<.000 1
-0.7
(-1.7, 0.4) 0.223 Pericardial
fat 0.247
-4.5 (-12.7,
3.7) 0.283
-6.8 (-14.9,
1.3) 0.1
-2.3 (-10.5,
5.9) 0.582
Contrast enhanceme
nt <.001
92.8 (59.1,
126.5) <.001
51.0 (17.8,
84.2) 0.003
-41.9 (-75.6,
-8.2) 0.015
CNR <.001
-3.2 (-4.4,
-2.0) <.001
-3.8 (-5.0,
-2.6) <.001 -0.6
(-1.8, 0.6) 0.326 BMI, body mass index; CI, confidence interval; CNR, contrast-to-noise ratio; HU,
Hounsfield unit; SNR, signal-to-noise ratio
Supplemental Digital Content 3. HU measurements with tube voltage as a covariate
370 mg I/ml 320 mg I/ml 270 mg I/ml
Average HU (HU) 531.3
(519.9, 542.6)
506.7 (497.6, 515.7)
445.2 (436.0, 454.5)
Noise 37.0
(34.0, 40.0) 45.0
(42.6, 47.5) 42.6
(40.1, 45.1)
SNR 14.6
(14.3, 14.8)
12.0 (11.8, 12.3)
11.2 (11.0, 11.5) Pericardial fat (HU) -94.3
(-101.6, -87.0) -101-4
(-107.3, -95.6) -103.7 (-109.7, -97.7) Contrast
enhancement (HU)
550.6 (542.4, 558.8)
642.5 (634.1, 650.8)
590.7 (582.6, 599.0)
CNR 17.7
(17.5, 18.0) 14.3
(14.1, 14.6) 13.7
(13.4, 13.9) Data are presented as mean (95% confidence interval).
BMI, body mass index; CNR, contrast-to-noise ratio; HU, Hounsfield unit; SNR, signal-to- noise ratio
Supplemental Digital Content 4. Comparative analysis of HU measurements with tube voltage as a covariate
Overall 370 vs 320 mg I/ml 370 vs 270 mg I/ml 320 vs 270 mg I/ml P-
value
Difference (95% CI)
p- value
Difference (95% CI)
p- value
Difference (95% CI)
p- value Average HU <.001 -24.6 (-
44.6, -4.6)
<.001 -86.1 (- 107, -65.5)
0.010 -61.4 (- 75.7, -47.2)
<.001
Noise 0.002 8.0 (-
1.4, 6.2) 0.001 5.6
(0.1, 11.1) 0.045 -2.4 (-
6.2, 1.4) 0.383
SNR <.001
-2.6 (- 3.0,
-2.1) <.001
-3.3 (- 3.7,
-2.9) <.001
-0.8 (- 1.2,
-0.3) <.001 Pericardial
fat 0.235 (, ) 0.553 (, ) 0.268 (, ) 0.1
Contrast enhanceme nt
<.001 91.9 (77.5, 106.2)
<.001 40.1 (26.0,
54.3)
<.001 -51.7 (- 66.0, -37.5)
<.001
CNR <.001 -3.4 (- 3.9, -2.9)
<.001 -4.1 (- 4.5, -3.6)
<.001 -0.7 (- 1.2, -0.2)
0.001 BMI, body mass index; CI, confidence interval; CNR, contrast-to-noise ratio; HU,
Hounsfield unit; SNR, signal-to-noise ratio
Supplemental Digital Content 5. Comparative analysis of the HU measurements and radiation dose in all patient
Overall 370 vs 320 mg I/ml 370 vs 270 mg I/ml 320 vs 270 mg I/ml P-
value Difference
(95% CI) p-
value Difference
(95% CI) p-
value Difference
(95% CI) p- value Average HU <.001 79.0 (45.0,
113.1) <.001 26.3 (-
7.4, 60.0) 0.126 -52.7 (- 86.9,
-18.6) 0.003
Noise <.001 14.0 (10.9,
17.2) <.001 12.1 (8.9,
15.2) <.001 -2.0 (-
5.2, 1.2) 0.222 SNR <.001 -2.7 (-
3.8,
-1.7) <.001 -3.4 (- 4.5,
-2.4) <.001 -0.7 (-
1.8, 0 .3) 0.173 Pericardial
fat 0.183 -4.7 (-
12.1, 2.8) 0.220 -6.8 (-
14.2, 0.6) 0.072 -2.1 (-
9.6, 5.4) 0.578 Contrast
enhanceme
nt <.001
83.7 (48.8,
118.6) <.001 33.1 (-
1.5, 67.6) 0.061 -50.6 (- 85.6,
-15.7) 0.005
CNR <.001 -3.5 (-
-2.3)4.7, <.001 -4.2 (-
-3.0)5.3, <.001 -0.7 (-
1.9, 0.5) 0.268
DLP <.001 133.0
(53.4,
212.6) <.001 110.4 (32.7,
188.1) 0.003 -22.6 (- 101.3,
56.1) 0.777
Effective
dose 0.003 (0.5, 3.4)1.9 0.005 1.6 (0.2
3.0) 0.024 -0.4 (-
1.9, 1.1) 0.833 CI, confidence interval; CNR, contrast-to-noise ratio; DLP, dose length product; HU, Hounsfield unit; SNR, signal-to-noise ratio