In vivo Application of the 2-Point Dixon Method by Deuterium Metabolic Imaging and Spectroscopy

Vinay R. Malut, Mario C. Chang, Geraldine L. Pierre, and Matthew E. Merritt

University of Florida

Magnetic resonance spectroscopy is a standard technique utilized to assess the distribution of various metabolites within tissues. However, spectroscopy may require relatively lengthy acquisition times and does not provide spatial information, limiting its diagnostic utility in clinical contexts. 2-Point Dixon (2PD) techniques preserve the ability to distinguish between different metabolites while encoding spatial information, allowing for the generation of metabolic images. This, combined with their shorter acquisition times, makes 2PD a valuable alternative to spectroscopy. However, careful optimization of imaging parameters and methods is necessary to achieve accurate and reliable separation of metabolite signals. In this work, we demonstrate the application of multi-gradient echo (MGE) techniques to perform a 2PD method and separately image partially-deuterated water (HDO) and [²H₇]glucose. To test our method, we imaged mouse brain metabolism before and after the injection of [²H₇]glucose and validated our imaging platform through a comprehensive analysis of glucose utilization kinetics measured by in vivo ²H spectroscopy. We performed global single pulse spectroscopy as well as selective slice spectroscopy throughout the course of our imaging paradigm to generate matched spectra and images of the same animal. Our work demonstrates clear separation of both HDO and [2H7]glucose, establishes a foundation for kinetic modeling of brain glucose utilization, and presents a platform for additional studies investigating altered brain metabolism. Given the safety of the tracer used, our work could be directly applicable to the clinical setting.