Magnetic Resonance Imaging using Proton Density Fat Fraction (MRI-PDFF) is a commonly used method to quantify the effect of pharmacological interventions on liver fat content. MRI-PDFF can be analysed in several ways, including via a) single Region-Of-Interest (ROI), b) multiple ROIs, c) assessment using up to 27 ROIs throughout the liver as reported by Le et.al1 or d) segmentation of the entire liver as reported by Tang et.al2. We have a developed a semi-automated tool to segment the entire liver from axial MRI data excluding veins and bile ducts. In addition to liver fat, this method also allows for rapid assessment of liver volume. The purpose of this study was to investigate the impact of different analysis methods on the detection of liver fat%, and to investigate the relationship between changes in liver fat and liver volume following weight loss intervention.