High Resolution MR Imaging of Brain Lactate Using Selective Saturation Transfer

Christopher Lascola^1,2, Talignair Venkatraman¹, Sean Snodgress¹, Haichen Wang³

Lactate is an important metabolic biomarker for a variety of neurological disease states, and is now also recognized as an essential substrate of neuronal metabolism [1]. An improved MR method for mapping brain lactate would aid the study of this important metabolite in physiologic and pathologic conditions, and provide a clinically relevant diagnostic tool. 13C and 1H MR spectroscopic (MRS) methods have been used previously to measure brain lactate concentrations but have limited temporal and spatial resolution. The purpose of this study is to investigate whether magnetic coupling between lactate methyl and water protons previously reported in MRS studies [2] and in phantoms [3] can be exploited to generate MRI contrast specific localized lactate accumulations. Our initial findings show that selective radiofrequency saturation of lactate methyl protons results in cumulative saturation of dominant water protons via immobilized macromolecules in both protein phantoms and in vivo, increasing the sensitivity of lactate detection in vivo as compared to MRS, and enabling high resolution mapping of subtle lactate changes in brain.