Mapping tissue water T1 in the liver using the MOLLI T1 method in the presence of fat, iron and B0 inhomogeneity

This article proposes an algorithm that provides an independent water MOLLIT1 (referred to as on ‐resonance waterT1) that would have been measured if a subject had no fat and normal iron, and imaging had been done on resonance. Fifteen NiCl2‐doped agar phantoms with different peanut oil concentrations and 30 adults with various liver diseases, nineteen (63.3%) with liver steatosis, were scanned at 3 T using the shortened MOLLI (shMOLLI)T1 mapping, multiple ‐echo spoiled gradient‐recalled echo and1H MR spectroscopy sequences. An algorithm based on Bloch equations was built in MATLAB, and water shMOLLIT1 values of both phantoms and human participants were determined. The quality of the algorithm's result was assessed by Pearson's correlation coefficient between shMOLLIT1 values and spectroscopically determinedT1 values of the water, and by linear regression analysis. Correlation between shMOLLI and spectroscopy ‐basedT1 values increased, fromr = 0.910 (P <  0.001) tor = 0.998 (P <  0.001) in phantoms and fromr = 0.493 (for iron‐only correction;P = 0.005) tor = 0.771 (for iron, fat and off‐resonance correction;P <  0.001) in patients. Linear regression analysis revealed that the determined water shMOLLIT1 values in patients were independent of fat and iron. It can be concluded that determination of on ‐resonance water (sh)MOLLIT1 independent of fat, iron and macroscopic field inhomogeneities was possible in phantoms and human subjects.
Source: NMR in Biomedicine - Category: Radiology Authors: Tags: RESEARCH ARTICLE Source Type: research