Table 3:

Linear mixed-effects model results using GE and Helical High Dose protocol as the reference for vendor and protocol, respectively. In this model, CT measurement depends on the true fat-fraction of each vial with fixed effects from vendor and protocol. CT number has high correlation with MRI-PDFF in a relationship with slope of −1.84±0.01 HU/%, intercept of 67.8±2.9 HU, and R²=0.997. CT vendor selection has a significant contribution (p<0.005) to the CT number versus MRI-PDFF calibration relationship (i.e., slope and intercept), however, CT protocol selection has no significant contribution (p>0.1) to the CT number versus MRI-PDFF calibration relationship (i.e., slope and intercept). PDFF, proton density fat-fraction.

			Coef.	Std.Err.	p	95% CI
Slope (HU/%)	Reference (GE)		−1.841	0.007	<0.001	[−1.855, −1.827]
	Vendor	Siemens	0.055	0.006	<0.001	[0.043, 0.067]
		Philips	0.024	0.008	<0.005	[0.008, 0.040]
	Protocol	Axial High Dose	−0.003	0.009	0.774	[−0.020, 0.015]
		Axial Low Dose	−0.001	0.009	0.968	[−0.018, 0.017]
		Helical Low Dose	0.004	0.009	0.685	[−0.014, 0.021]
		AAPM	0.013	0.009	0.154	[−0.005, 0.031]
Intercept (HU)	Reference (Helical High Dose)		67.8	2.9	<0.001	[62.1, 73.4]
	Vendor	Siemens	−5.6	0.2	<0.001	[−6.0, −5.1]
		Philips	−3.0	0.3	<0.001	[−3.6, −2.4]
	Protocol	Axial High Dose	−0.1	0.3	0.798	[−0.7, 0.6]
		Axial Low Dose	−0.4	0.3	0.188	[−1.1, 0.2]
		Helical Low Dose	−0.4	0.3	0.231	[−1.1, 0.3]
		AAPM	−0.4	0.3	0.288	[−1.0, 0.3]

Note: Coef., coefficient; Std.Err., standard error; 95% CI, 95% confidence interval; AAPM, American Association of Physicists in Medicine.