Determination of absolute concentrations of cardiac highenergy phosphates using 31P-MR-spectroscopy and SLOOP in healthy and diseased myocardium

Purpose: A quantitative 31P-MR-spectroscopic technique was used to assess the energy metabolism in healthy and diseased myocardium. Methods: 31P-spectra were acquired on a 1.5 T scanner using a 3D-chemical shift imaging technique. Based on the anatomical information provided by 1H- images, SLOOP (Spatial Localization with Optimal Pointspread Function) allows to obtain spectra from defined compartments. With SLOOP a free voxel shape with adaption to anatomic structures, e.g. the myocardium, is possible. Absolute values for phosphocreatine (PCr) and adenosine triphosphate (ATP) were determined using an external standard. Results: 31P-spectra showed only minimal contamination by surrounding tissue. The standard deviation for the determined values of healthy volunteers was low. Compared to healthy volunteers, reduced PCr and ATP concentrations were seen for dilative cardiomyopathies and coronary artery disease and unchanged concentrations were observed for hypertensive heart disease. Conclusion: 31P-MR- spectroscopy with SLOOP allows a non-invasive, quantitative analysis of cardiac energy metabolism