Simultaneous Quantification of Fat Fraction and Fatty Acid Composition Using MRI

Introduction The distinction between non-alcoholic fatty liver disease (NAFLD) and steatohepatitis is currently only possible using invasive techniques. Possibly, the fatty acid (FA) composition of hepatic fat may be able to discriminate between the two conditions [1]. MR spectroscopy (MRS) has been proposed as a non-invasive method of estimation of FA composition [1-3]. Hamilton et al. have recently suggested the use of theoretical knowledge of the chemical structure of FAs to achieve detailed information on the FA composition from H-MRS measurements [2]. In addition, an MR-imaging technique would provide spatial information in case of a non-diffuse disease. In a previous work, we were able to use multi-echo imaging to quantify the fraction unsaturated FA (UF) [4]. However, not including water, this technique required the estimation of seven unknowns.