There is an ongoing debate in the myelin imaging community about which MR-based biomarker has the greatest precision, sensitivity and specificity to myelin. In this work, we compared several MR-based myelin imaging techniques (quantitative magnetization transfer, myelin water fractions, and macromolecular tissue volume) by evaluating their repeatability and their relation to large-scale histology in dog spinal cord. Qualitatively the contrasts were similar, and all techniques had comparable scan-rescan and correlations with histology. Surprisingly, the correlations between the various myelin measures were almost as high as the scan-rescan correlations. The correlations decreased when only white matter was considered, which could be due to the small dynamic range of the measurement, or due to artifacts related to the preparation and panoramic scanning of the tissue.