Table 1. Detailed information of CT imaging protocol.

Hospital	Manufacturers model name	Tube current (mAs)	Tube volume (kVp)	Pitch (mm)	Matrix	Slice thickness (mm)
Hospital 1	Aquilion ONE	100	100	0.828	512×512	5
	Discovery CT750 HD	300	120	0.984	512×512	5
	iCT 256	103	120	0.758	512×512	5
	IQon-Spectral CT	108	120	0.765	512×512	5
	LightSpeed16	280	120	1.375	512×512	5
	LightSpeed VCT	145	120	1.375	512×512	5
	SOMATOM Definition Flash	360	120	1.2	512×512	5
	uCT 528	106	120	1.325	512×512	1.5
	uCT 760	194	120	1.0875	512×512	5
	uCT S-160	100	120	1.1	512×512	5
Hospital 2	Perspective	150	110	0.6	512×512	1
	uCT 760	158	120	1.0875	512×512	1.25
Hospital 3	Discovery CT	185	120	1.375	512×512	0.625
	SOMATOM Definition AS+	138	120	1.2	512×512	1
	uCT 760	185	120	1.0875	512×512	0.625
	uCT 530	187	120	1.175	512×512	1
Hospital 4	Brilliance16	188	120	1.1	512×512	2
	Brilliance 64	308	120	1.2	512×512	1
Hospital 5	SOMATOM Definition AS+	151	120	1.2	512×512	1.5
	Brilliance16	188	120	1.1	512×512	2
Hospital 6	LightSpeed VCT	150	120	1.375	512×512	5
	SOMATOM Definition Flash	329	120	1.2	512×512	1
Hospital 7	LightSpeed16	250	120	1.375	512×512	1.25
	LightSpeed Ultra	250	120	0.875	512×512	2.5
	Revolution Frontier	219	120	0.984375	512×512	1.25
Hospital 8	Aquilion ONE	172	120	0.813	512×512	5
	SOMATOM Perspective	128	120	0.95	512×512	1
Hospital 9	uCT 510	174	120	1.0625	512×512	1.5
	uCT 528	42	120	1.15	512×512	1.2
Hospital 10	LightSpeed16	250	120	1.375	512×512	5
	LightSpeed VCT	349	120	1.375	512×512	5
	uCT 510	185	120	1.1875	512×512	1.5
Hospital 11	SOMATOM Definition AS+	279	120	1.2	512×512	0.6

A total of 33 CT scanners from 11 hospitals were used in this study. Tube current, tube volume, pitch, matrix and slice thickness were described. CT, computed tomography.