Diffusion measurement of Mobile Lipids using co-resonant coupled metabolite dephasing

Introduction: The H spectra of certain tumor cells, in vivo tumors and biopsies, show an intense resonance in the 1.26-1.30 ppm area that has been usually assigned to NMR visible mobile lipids (MLs) . The presence of large ML signal seems to correlate with necrotic areas in the tumors 3 and the non-invasive detection of necrosis would suggest a high grade of malignancy in untreated tumors or could be used to monitor the response to tumor therapy . The MLs remain visible at long echo times (TE = 136 ms) and were investigated in different studies using diffusion weighted NMR spectroscopy . The altered glycolysis in many tumors results in a lactate (Lac) accumulation and an increased Lac CH3 signal at 1.31 ppm, which is overlapping with MLs and complicates its analysis. In this study a single scan selective spin-echo sequence for the MLs is presented, where an additional selective pulse on the Lac CH pulse minimizes Lac CH3 contribution to the ML signal.