High-resolution quantitative MRI of multiple sclerosis spinal cord lesions

Abstract

Purpose: Validation of quantitative MR measures for myelin imaging in the postmortem multiple sclerosis spinal cord.

Methods: Four fixed spinal cord samples were imaged first with a 3T clinical MR scanner to identify areas of interest for scanning, and then with a 7T small bore scanner using a multicomponent-driven equilibrium single-pulse observation of T₁ and T₂ protocol to produce apparent proton density, T₁ , T₂ , myelin water, intracellular water, and free-water fraction maps. After imaging, the cords were sectioned and stained with histological markers (hematoxylin and eosin, myelin basic protein, and neurofilament protein), which were quantitatively compared with the MR maps.

Results: Excellent correspondence was found between high-resolution MR parameter maps and histology, particularly for apparent proton density MRI and myelin basic protein staining.

Conclusion: High-resolution quantitative MRI of the spinal cord provides biologically meaningful measures, and could be beneficial to diagnose and track multiple sclerosis lesions in the spinal cord.

Keywords: multiple sclerosis; myelin water fraction; spinal cord.