. Author manuscript; available in PMC: 2012 May 1.

Published in final edited form as: Magn Reson Imaging. 2011 Jan 31;29(4):561–567. doi: 10.1016/j.mri.2010.10.011

Table 1.

Estimated accuracy and precision of T₂s and associated weights from multiexponential fits.

Group		T_2,PG	T_2,LB	w_PG	w_LB
Fresh	Accuracy	−14.94	−0.62	−8.37	2.08
Fresh	Precision	0.29	0.01	0.34	0.13
Frozen	Accuracy	−18.26	−0.31	−10.42	1.15
Frozen	Precision	0.41	0.01	0.33	0.13

Simulations results for accuracy and precision. Accuracy is defined as average percent error. Precision is reported as the coefficient of variation (CV), defined as the standard deviation over 100 noise realizations divided by the input parameter value × 100. Reliability (not shown), defined as correctly identifying the number of input T₂ components, was 100 percent for both young and mature tissue. Reported values are estimated using the average experimental SNRs of 13,249 and 16,301, for fresh and frozen BNC, respectively. In each case, 100 noise realizations using the average T₂s and associated weights as input values were simulated. Simulation input values for the PG component, C_PG, and the loosely-bound water component, C_LB, for fresh and frozen tissue were (T₂ ms, % magnetization): fresh C_PG = (36.61ms, 6.57%) and C_LB = (108.08ms, 83.92%); frozen C_PG = (36.31ms, 3.12%) and C_LB = (119.31ms, 89.16%).