Assessment of the Diurnal Variability of Hepatic Fat Concentration

The goal of this proposal is to assess the diurnal variability of liver fat concentration in asymptomatic adult subjects. Determining the diurnal variability will provide a reference for analyzing the performance of fat quantification techniques as well as for evaluating whether treatments aimed at reducing liver fat concentration provide statistically significant effects.
Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the US, affecting approximately 95 million Americans. The hallmark histological feature of NAFLD is fatty liver, which without proper treatment, can progress to severe conditions including fibrosis, cirrhosis, and liver failure. Thus, the ability to diagnose and treat fatty liver in its early stages is crucial for improving the outcome of patients with NAFLD.
Advanced chemical shift encoded MRI (CSE-MRI) techniques have been developed and validated for measuring liver fat concentration. However, in order to understand their clinical value, the performance (e.g. repeatability) of these techniques must be determined in the context of the normal diurnal variability of liver fat concentration. Normal changes in fat concentration throughout the day, with regards to meals and changes in hydration status (which in theory affects the concentration of water in tissue, and therefore relative fat concentration) is unknown. Furthermore, treatment options including pharmaceutical-based and surgery are under development. To evaluate the efficacy of these different treatment options, their effect must be placed into context with the diurnal variability of liver fat concentration.
In this study, we propose to assess the diurnal variability of liver fat concentration in asymptomatic adult subjects. Furthermore, we will measure the liver fat concentration throughout the day using a CSE-MRI-based quantitative technique, which provides a safe, accurate, and non-invasive means for assessment. Upon successful completion, this study will establish the diurnal variability of liver fat concentration, to be used for understanding the clinical value of techniques that measure liver fat concentration as well as for evaluating the efficacy of treatments aimed at reducing excessive fat accumulation.