Quantification of Apparent Tissue Sodium Concentration (aTSC) in the Healthy Liver via 23Na and 1H MRI at 7T

Motivation: This study seeks to enhance the appeal of using quantitative 23Na MRI in clinical settings by providing essential reference data for healthy tissue. Goal(s): The goal is to determine the mean aTSC in the healthy liver as reference for diseased livers and to identify potential methodological limitations. Approach: In this study, we determined liver aTSC in 7 healthy volunteers using 1H images for segmentation and B1+- and B1--corrected 23Na images for quantification. Results: The healthy liver's aTSC was found to be (37.0 ± 11.4) mmol/l after fasting overnight, potentially impacted by nutrition, voxel model for B1- corrections, and sodium calibration setup. Impact: This study provides essential reference data for 23Na MRI in healthy livers and also highlights the need to investigate correlations between aTSC, B1- correction, food intake, and calibration methods in healthy livers.