Computed tomography pulmonary angiography using a 20% reduction in contrast medium dose delivered in a multiphasic injection

Table 1 Characteristics of the study population

	60 mL	75 mL (control)
Size	57	70
Gender (M:F)	23:34	32:38
Mean age (yr)	65.7	62.7
Age range (yr)	34-93	16-92

M: Male; F: Female.

Table 2 A comparison of mean opacification values in the pulmonary arteries between the two groups

	Mean opacification ± standard deviation
	60 mL of contrast agent	75 mL of contrast agent	Mean difference (95%CI)
Main pulmonary artery	437 ± 121	438 ± 142	1 (-45 to 47)
Right pulmonary artery	417 ± 115	420 ± 130	3 (-41 to 47)
Left pulmonary artery	417 ± 110	424 ± 140	7 (-38 to 50)

All values are given in Hounsfield units.

Table 3 Number of sub-optimal studies in each group

Group	Number of sub-optimal studies
75 mL	10
60 mL	7
	P = 0.96