Table 1.

Least squares linear regression correlation coefficient (R), intercept and slope for the principal frequency and LFE-based shear stiffness estimation inversion algorithms as a function of inflation (i.e transpulmonary (P_tp)) pressure. The R and slopes were calculated for each data set which consisted of between two to five points (slices) per P_tp value. Both LFE and principal frequency values represent the average shear stiffness within the lung within each slice with each point corresponding to a single slice.

	Principal Frequency-Based Shear Stiffness			Local Frequency Estimation (LFE)-Based Shear Stiffness
Data Set	Intercept (kPa)	Slope	R	Intercept (kPa)	Slope	R
1	1.42	0.720	0.642	1.36	-0.169	-0.264
2	1.72	1.35	0.856	1.76	-0.0126	-0.0186
3	1.67	1.14	0.777	1.69	-0.225	-0.256
4	1.66	1.93	0.825	1.70	0.392	0.384
5	2.15	1.79	0.855	1.98	-0.705	-0.649

Note: Before performing the least squares linear regression, P_tp values were converted from units of centimeters of H₂O to kPa (1 cm H₂O (at 4 °C) = 0.0981 kPa). Therefore the slope and R values quoted in this table are unit less.