Table 3b.

Repeatability results for Patient #5 returning 22 months later.

Repeatability Results	Renal Tissue Stiffness (kPa)
	at 90 Hz	at 120 Hz	at 150 Hz
MRE #1	5.2 ± 1.9	7.0 ± 2.3	8.9 ± 2.9	(8.9 ± 2.3)
MRE #2	5.5 ± 1.7	7.5 ± 2.1	9.7 ± 2.5	(9.7 ±− 2.2)
MRE #3	5.4 ± 1.7	7.3 ± 4.5	9.5 ± 36.2§	(8.8 ± 2.1)
mean	5.4	7.3	9.4	(9.1)
sd	0.2	0.3	0.4	(0.5)
COV	2.9%	3.5%	4.4%	(5.4%)

^§Large standard deviation is due to spikes (outliers) in the elastogram. Since the median is a more robust measure of the central value in this case, we parenthetically report the “trimmed mean and standard deviation.” Data more than three standard deviations above or below the median of the original ROI data were removed to exclude outliers while maintaining 99.7% of the original data, and then the mean and standard deviation of the remaining data were reported. This methodology was also performed for the other data which did not have significant outliers, and as expected, the other data were minimally affected.

Tissue stiffness values were determined using a 3×3×3 DI DF algorithm. Level of pathological fibrosis (NS: no significant fibrosis; Mild: mild fibrosis; Mod: moderate fibrosis; Non-Dx: non-diagnostic) based on Banff criteria is noted for each patient (Table 3a). MRE at 150 Hz vibrations was not performed on the first two patients in the study (denoted by “NA.”). MRE was repeated three times with complete disassembly and reassembly of the MRE apparatus between each repetition for Patient #5 who returned for clinical follow-up 22 months later (Table 3b).