Comparative Evaluation of Single-Voxel and Multi-Voxel Proton Magnetic Resonance Spectroscopy Using Small-Sized Voxels in Healthy Beagle Dogs: A Pilot Study.

Magnetic resonance imaging has limitations in definitively diagnosing canine brain diseases due to overlapping lesion morphologies. Magnetic resonance spectroscopy (MRS) can complement conventional MR imaging by evaluating brain metabolites at a molecular level, though voxels under 1 cm3 have not been routinely evaluated in veterinary medicine. This study evaluated the usefulness of single-voxel spectroscopy (SVS) using small-sized voxels (0.125 cm3) by comparing it with multi-voxel spectroscopy (MVS). Both techniques were performed on the white matter and gray matter of the frontoparietal lobe, the caudate nucleus, and the thalamus in seven healthy beagle dogs using a 1.5T system. Brain metabolite concentrations and their ratios to creatine were compared. SVS had a significantly shorter mean acquisition time (4.79 ± 0.29 min) than MVS (11.64 ± 0.23 min). No significant differences were observed in metabolite concentrations or ratios between SVS and MVS following multiplicity correction, confirming no statistically significant discrepancies between the two protocols. No significant differences were found between the left and right hemispheres. While small-voxel SVS is technically feasible and reduces scan time, these findings represent protocol-specific descriptive data in a small sample of healthy dogs and do not establish clinical reference values or diagnostic accuracy.