31P-MRS saturation transfer to assess hepatic ATP synthesis at 3T in individuals with type-1-diabetes and control volunteers

Motivation: 31P-MRS saturation transfer for detection of adenosine triphosphate (ATP) synthesis is currently almost exclusively performed at ultrahigh field. Goal(s): Establishing a method to robustly assess ATP synthesis in human liver using a clinical MRI system. Approach: A 2D-ISIS sequence was used to assess the hepatic apparent spin-lattice relaxation time of inorganic phosphate (T'1,Pi), equilibrium forward rate constant (kf) and forward ATP exchange flux (FATP) in healthy volunteers (n=9) and participants with type-1-diabetes (T1D) (n=8). Results: Reproducibility measurements resulted in CVs of 7.1% and 21.3% for T'1,Pi and kf, respectively. Mean hepatic kf and FATP were lower (p=.001 and p=.002) in T1D vs. controls. Impact: To make the 31P-MRS ST technique more broadly available for metabolic research, the method is established on a clinical scanner, allowing investigation of ATP synthesis in the liver with good localization and is sensitive to changes occurring with T1D.