Table 2.

Patient demographic and dosage characteristics

	Standard-dose CT	Low-dose CT (n = 137)	p-value
Demographic characteristic
Male-to-female ratioa	61:65	72:65	0.58
Age (year)	44.9 ± 15.4	43.8 ± 14.7	0.55
Male	42.4 ± 14.7	41.5 ± 13.8	0.72
Female	47.5 ± 16.0	46.0 ± 15.8	0.59
BMIa
Group 1b	35	34	0.68
Underweight	1	2	0.98
Lower range of the normal weight	34	32
Group 2c	60	64	0.98
Group 3d	31	39	0.57
Overweight	28	34	0.73
Obese	3	5	0.84
Dose characteristic
mAs	237.3 ± 67.2	121.8 ± 34.1	<0.001
Volume CT dose index (mGy)	11.9 ± 3.8	6.2 ± 2.8	<0.001
Dose-length product (mGy × cm)	360.5 ± 59.7	188.4 ± 21.5	<0.001
Effective dose	4.9 ± 2.3	2.1 ± 0.9	<0.001
BMI Group 1	3.6 ± 1.8	1.1 ± 0.4	<0.001
BMI Group 2	4.7 ± 2.1	2.0 ± 0.8	<0.001
BMI Group 3	5.7 ± 2.9	3.0 ± 1.4	<0.001

Unless otherwise specified, data are means ± standard deviations. BMI, body mass index; CTDI_vol, volume CT dose index; DLP, dose-length product.

^aData are numbers of patients.

^bUnderweight (<18.5 kg m^–2) and lower range of the normal weight (18.5–22.9 kg m^–2).

^cUpper range of the normal weight (23–24.9 kg m^–2).

^dOverweight (25–29.9 kg m^–2) and obese (≥30 kg m^–2).