arXiv:2603.08829v1 Announce Type: new
Abstract: How the human brain adjusts fuel handling and its bioenergetic state during changing glucose levels remains difficult to assess noninvasively. In this study, we established an interleaved multinuclear 7 T MR spectroscopy protocol to track a glucose-related 1H signal alongside 31P measures of high-energy phosphate metabolism during a hyperglycemic clamp. Five healthy adults completed a morning, fasted infusion experiment consisting of baseline, ramp-up, and hyperglycemic stages over approx. 120 min. Short-block, short-TE 1H single-voxel spectroscopy (STEAM, TE = 11 ms; mean block duration 5.71 (SD:0.62 min)) was acquired in frontal cortex and quantified using the composite Glucose+Taurine (Glc+Tau) measure. 31P was acquired with rapid 3D PETALUTE MRSI using an ultrashort echo time (UTE; TE = 65 micros; 381 s per block), and high-energy phosphate ratios were derived from a posterior cortical region of interest. Across participants, 1H Glc+Tau increased with blood glucose and showed significant elevations from baseline into hyperglycemia. In parallel, 31P ratios exhibited smaller but significant glycemia-linked responses: both PCr/Pi and gamma-ATP/Pi increased with blood glucose and differed across glucose clamp stages. These findings show that 1H and 31P MRS(I) can be interleaved at 7 T to measure energy metabolism within a single session