Abstract
Concentrations of the key metabolites of hepatic energy metabolism, adenosine triphosphate (ATP) and inorganic phosphate (P ), can be altered in metabolic disorders such as diabetes mellitus. Phosphorus ( P)-magnetic resonance spectroscopy (MRS) is used to noninvasively measure hepatic metabolites, but measuring their absolute molar concentrations remains challenging. This study employed a P-MRS method based on the phantom replacement technique for quantifying hepatic P-metabolites on a 3-T clinical scanner. Two surface coils with different size and geometry were used to check for consistency in terms of repeatability and reproducibility and absolute concentrations of metabolites. Day-to-day (n?=?8) and intra-day (n?=?6) reproducibility was tested in healthy volunteers. In the day-to-day study, mean absolute concentrations of ?-ATP and P were 2.32?±?0.24 and 1.73?±?0.26?mM (coefficient of variation [CV]: 7.3% and 8.8%) for the single loop, and 2.32?±?0.42 and 1.73?±?0.27?mM (CVs 6.7% and 10.6%) for the quadrature coil, respectively. The intra-day study reproducibility using the quadrature coil yielded CVs of 4.7% and 6.8% for ?-ATP and P without repositioning, and 6.3% and 7.1% with full repositioning of the volunteer. The results of the day-to-day data did not differ between coils and visits. Both coils robustly yielded similar results for absolute concentrations of hepatic P-metabolites. The current method, applied with two different surface coils, can be readily utilized in long-term and interventional studies. In comparison with the single loop coil, the quadrature coil also allows measurements at a greater distance between the coil and liver, which is relevant for studying people with obesity.
Original language | English |
---|---|
Article number | 5120 |
Journal | NMR in Biomedicine |
DOIs | |
Publication status | E-pub ahead of print - 25 Feb 2024 |
Keywords
- absolute quantification
- hepatic adenosine triphosphate
- hepatic inorganic phosphate
- reproducibility of 31P-MRS
- surface coil