Removing barriers for lactate quantification in the portal vein using deuterium metabolic imaging

Introduction: Chronic mesenteric ischemia (CMI) results from reduced mesenteric blood flow. Its diagnosis is challenged by nonspecific symptoms and large morphological variability. Detecting lactate via 2H-MRSI in the portal vein could serve as a function test but may be affected by respiratory motion. This study assesses the impact of the current practice of non-gated acquisition on spectral quality, linewidth, signal-to-noise ratio, Cramér-Rao Lower Bounds and repeatability of quantification. Moreover, stomach-induced ghosting is simulated and suppressed in a phantom. Methods: The impact of respiratory motion on spectra was investigated in the liver using 31P-MRSI at 7T. Gated free breathing, non-gated free breathing and non-gated deep breathing scans were compared. Ghosting was investigated using a phantom simulation with a moving acetone container as surrogate for the stomach using 1H-MRSI at 1.5T. Results: No clear difference was found between gated and non-gated free breathing acquisitions. Deep breathing consistently performed worse in every aspect. Ghosting artifacts were successfully simulated and suppressed with a REST-slab-suppressive sequence. Impact: This study found no evidence that non-gated acquisition negatively affects liver MRSI in free breathing. Moreover, ghosting reduction appears feasible. Further research is required to confirm the applicability of these findings for 2H-MRSI in the portal vein.