Diffuse signal abnormalities in the spinal cord in multiple sclerosis: Direct postmortem in situ magnetic resonance imaging correlated with in vitro high‐resolution magnetic resonance imaging and histopathology

Abstract
In this study, we compared direct postmortem in situ (whole‐corpse) sagittal spinal cord magnetic resonance imaging (1.5T) of 7 multiple sclerosis cases with targeted high‐resolution in vitro axial magnetic resonance imaging (4.7T) and histopathology. On sagittal in situ magnetic resonance imaging, 1 case had a normal spinal cord, 2 had only focal lesions, 3 had a combination of focal and diffuse abnormalities, and 1 had only diffuse abnormalities. All spinal cords showed abnormalities on high‐resolution magnetic resonance imaging and histopathology, confirming the existence of diffuse cord changes as genuine multiple sclerosis‐related abnormalities while highlighting the limited resolution of in vivo magnetic resonance imaging.