Influence of the analysis technique on estimating hepatic iron content using MRI

El-Sayed H. Ibrahim, Ayman M. Khalifa, Ahmed K. Eldaly
2016 Journal of Magnetic Resonance Imaging  
Purpose: To investigate the effect of the analysis technique on estimating hepatic iron content using MRI Materials and Methods: We evaluated the influences of single-exponential (EXP), biexponential (BEXP), and exponential-plus-constant (CEXP) models; and pixel-wise (MAP), average (AVG), and median (MED) signal calculation methods on T2* measurement using numerical simulations, calibrated phantoms, and nine patients scanned on 3T MRI, based on regression, correlation, and t-test statistical
more » ... lysis. Results: The T2* measurement error varied from 9 to 51% in the numerical simulations (T2*:5-20ms), depending on signal-to-noise ratio (SNR;range:8-233) with significant (P<0.05) difference between actual and predicted values. The MAP method performed well (error<10%) at high SNR (>100), but resulted in severe estimation errors at low SNR (<50). The EXP model resulted in significant measurement differences (P<0.05) compared to all other methods, irrespective of SNR. In-vivo T2* values ranged from 3.1 to 53.6ms, depending on the amount of iron overload and implemented analysis method. The BEXP (range:3.7-50ms) and CEXP (range:3.8-53.6ms) models, and the AVG (range:3.2-38.8ms) and MED (range:3.1-38.5ms) methods provided more accurate measurements than the EXP model (range:3.1-18.3ms) and MAP (range:3.8-53.6ms) method, respectively (P<0.05). The BEXP and CEXP models provided very similar measurements (P>0.87). Similarly, the AVG and MED methods provided very similar results (P>0.97), with slightly better performance of the AVG method. Conclusion: Different analysis techniques show different performances based on the fitting model and signal calculation method. Based on this study, the CEXP model and
doi:10.1002/jmri.25317 pmid:27240936 fatcat:twa2s47upfde3owjzw27dllwqi