. Author manuscript; available in PMC: 2018 Dec 1.

Published in final edited form as: Abdom Radiol (NY). 2017 Dec;42(12):2843–2854. doi: 10.1007/s00261-017-1206-4

Table 5.

Relative ROI sizes under different conditions for 2D and 3D MRE

	2D MRE		3D MRE

Condition	Difference in ROI size	p- value	Difference in ROI size	p- value
Expiration – inspiration	10.9 cm² (2.5, 19.3)	0.01	−14.6 cm² (−50.1, 20.8)	0.42
Expiration – inspiration	15.0% (3.4%, 25.6%)	0.01	−4.4% (−15.2%, 6.3%)	0.42
Rigid – flexible driver	1.7 cm² (−6.7, 10.0)	0.69	29.5 cm² (−10.2, 61.7)	0.11
Rigid – flexible driver	2.3% (−9.5%, 14.2%)	0.69	8.4% (−2.9%, 17.6%)	0.11

For 2D and 3D MRE, difference in sizes of ROIs drawn for different conditions (expiration vs. inspiration; rigid driver vs. flexible driver) were estimated using an LME model. Shown are the mean differences and their 95% confidence intervals (as well as the mean percent differences and their 95% confidence intervals). A positive mean difference means ROI size was larger in expiration or using the rigid driver, depending on the condition being modeled. There was no interaction between driver and respiratory phase. Percentage difference for expiration vs. inspiration is defined as (stiffness in expiration − stiffness in inspiration)/(stiffness in expiration). Percentage difference in stiffness between rigid vs. flexible driver is defined as (stiffness using rigid driver − stiffness using flexible driver)/(stiffness using rigid driver).