Table 3.

Effect of partial humeral head inclusion on radiation dose

Patient characteristics	All scans (n = 90)			Scans arms out (n = 35)			Scans arms in (= 55)			P-value
Body mass index (kg/m2)	90	21.1	(19.5; 22.4)	55	21.0	(19.6; 22.1)	35	21.6	(19.0; 23.0)	0.634
Weight (kg)	90	62.0	(57.5; 67.9)	55	61.2	(56.9; 67.5)	35	62.7	(58.2; 69.0)	0.317
Height (cm)	90	172.0	(168.0; 177.5)	55	171.0	(167.0; 177.0)	35	174.0	(170.0; 178.0)	0.081
Scan characteristics
CT scan length (cm)	90	4.9	(4.2; 5.4)	35	4.9	(4.2; 5.2)	55	4.8	(4.4; 5.5)	0.904
Scan length group, n (%)	90			35			55
≤ 4 cm		26	(28.9)		10	(28.6)		16	(29.1)
> 4 cm		64	(71.1)		25	(71.4)		39	(70.9)	0.958
Total humeral head inclusion (R&L) (cm)	90	0.4	(0.0; 2.3)	35	0.0	(0.0; 0.0)	55	1.8	(0.8; 3.60	< 0.001
Right humeral head inclusion (cm)	90	0.0	(0.0; 1.2)	35	0.0	(0.0; 0.0)	55	0.9	(0.2; 1.9)	< 0.001
Left humerus head inclusion (cm)	90	0.1	(0.0; 1.0)	35	0.0	(0.0; 0.0)	55	0.9	(0.3; 1.70	< 0.001
Humeral head position, n (%)	90			35			55
Arms in		55	(61.1)		0	(0.0)		55	(100.0)
Arms out		35	(38.9)		35	(100.0)		0	(0.0)	< 0.001
Humeral head inclusion/scan length, n (%)	90			35			55
Arms out, SL: ≤4 cm		10	(11.1)		10	(28.6)		0	(0.0)
Arms in, SL: ≤4 cm		16	(17.8)		0	(0.0)		16	(29.1)
Arms out, SL: >4 cm		25	(27.8)		25	(71.4)		0	(0.0)	< 0.001
Arms in, SL: >4 cm		39	(43.3)		0	(0.0)		39	(70.9)
Radiation doses
Effective CT tube current (mAs)	90	65.5	(58.0; 81.0)	35	58.0	(50.0; 74.0)	55	68.0	(61.0; 84.0)	< 0.001
CT dose index (mGy)	90	4.5	(3.9; 5.5)	35	3.9	(3.4; 5.0)	55	4.7	(4.2; 5.7)	0.001
Dose length product (mGy*cm)	90	30.0	(27.0; 38.0)	35	29.0	(24.0; 32.0)	55	33.0	(28.0; 42.0)	0.003
Effective dose (mSv)	90	0.4	(0.4; 0.5)	35	0.4	(0.3; 0.4)	55	0.5	(0.4; 0.6)	0.003

Continuous variables are described with median (IQR), p-values obtained by Wilcoxon rank sum test

Categorical variables are shown with number (%) in each category, p-values obtained by Chi-squared test or by Fisher’s exact test if appropriate