Determination of myocardial triglyceride using magnetic resonance imaging Cardiac abnormalities in diastolic and systolic function can be associated with excessive lipolysis and lipotoxic injury to cardiomyocytes in animal models. The overstorage of lipids, known as cardiac steatosis, produces lipotoxic substances that result in oxidative stress and can cause apoptosis. Measurement of the ectopic fat deposition in the myocardium may provide a useful index of the degree of lipid overload. The overall aim of this proposal is to develop robust imaging biomarkers using magnetic resonance imaging (MRI) to improve the diagnosis accuracy and characterization of cardiac steatosis. Several methods have been employed to quantify ectopic fat deposition in humans. Proton Magnetic Resonance Spectroscopy (1H MRS) has proven to be reliable and reproducible in measuring myocardial triglyceride content in humans. However, MRS is a relatively complicated and time-consuming method requiring extensive post-processing. New opportunities may be available to quantify fatty infiltration using MRI. To accurately quantify the fat fraction, four major issues should be addressed: the effect of tissue relaxation, image noise, and the field in homogeneity that results in a shift of in- and out-phase echo times. Over the past years, however, the PI has addressed the issues of accurate assessment of steatosis. In the first phase of this proposal, the focus is on the technical developments and ex-vivo experiments to validate our novel concepts and new fat-water separation methods at 3.0T magnetic field. Next, we will evaluate this technique in patients in correlation to the MRS results. We will evaluate patients with diabetes or HIV infection in a 3.0T clinical setting using the proposed methods. Ultimately we propose to achieve quantification of steatosis with less than 0.5% error to provide accurate assessment of steatosis for close monitoring of the disease progress. PUBLIC HEALTH RELEVANCE: Determination of myocardial triglyceride using magnetic resonance imaging the over-storage of fat in the heart muscle, known as cardiac steatosis, produces lipotoxic substances that result in cardiac abnormalities in diastolic and systolic function and can cause heart cell death. The overall aim of this proposal is to develop robust imaging biomarkers using magnetic resonance imaging (MRI) to improve the diagnosis accuracy and characterization of cardiac steatosis.