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

Table 1 Computed tomography parameters for the conventional and multi-modality treatment groups

Dose group	Conventional group	Multi-modality group
Tube voltage, kV	100	80
Tube current, mA	Smart milliampere	80% smart milliampere
D-FOV, mm	220	220
Rotation time, s	0.275	0.275
Thickness, mm	0.5	0.5
Interval, mm	0.5	0.5
AIDR3D	Standard EU10	Standard EU10
Scanning method	ECG gating	ECG gating
Cardiac cycle	30%-80%	60%-80%
Scan position	Conventional	Isocentric
Scan length	140 mm	140 mm

AIDR3D: Adaptive Iterative Dose Reduction Using Three Dimensional Processing; ECG: Electrocardiography.

Table 2 Characteristics of the two groups

Group, n	Sex, F/M	Age, yr	BMI, kg/m2	CTDvol, mGy	DLP, mGy × cm	ED, mSv
A1, n = 82	31/51	59.59 ± 9.66	23.06 ± 1.95	5.89 ± 1.85	80.58 ± 24.80	1.13 ± 0.36
A2, n = 36	19/20	64.15 ± 13.28	22.58 ± 1.96	17.92 ± 8.02	250.90 ± 112.25	3.36 ± 1.30
P value	0.43	0.17	0.89	0.00	0.00	0.00

BMI: Body mass index; CTD_vol: Computed tomography dose index volume; DLP: Dose length product; ED: Effective dose; F: Female; M: Male.

Table 3 Computed tomography values and objective image quality scores for the aortic roots and proximal coronary vessels

Group, n	Aortic root, HU			Noise
A1, n = 82	512.18 ± 108.22	477.20 ± 117.93	485.88 ± 4100.40	15.52 ± 4.73	66.00 ± 25.30	41.32 ± 16.13
A2, n = 39	601.92 ± 125.34	534.67 ± 117.33	546.99 ± 109.30	19.29 ± 6.26	54.28 ± 17.72	38.45 ± 12.06
P value	0.07	0.32	0.37	0.00	0.00	0.00

HU: Hounsfield unit.

Table 4 Subjective image quality scores and the number of score segments in the two groups

Group	All segments	5	4	3	2	1	Average IQ score
A1	1085	420 (38.71%)	611 (56.48%)	45 (4.15%)	6 (0.55%)	1 (0.09%)	4.46 ± 0.59
A2	518	258 (49.81%)	232 (44.79%)	19 (3.67%)	8 (1.54%)	1 (0.19%)	4.45 ± 0.62
P value							0.12

IQ: Image quality.