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Abstract #22891 Published in IGR 11-1
Assessing optic nerve pathology with diffusion MRI: From mouse to human
Xu J; Sun S-W; Naismith RT; Snyder AZ; Cross AH; Song S-KNMR in Biomedicine 2008; 21: 928-940
See also comment(s) by Yeni Yucel •
The optic nerve is often affected in patients with glaucoma and multiple sclerosis. Conventional MRI can detect nerve damage, but it does not accurately assess the underlying pathologies. Mean diffusivity and diffusion anisotropy indices derived from diffusion tensor imaging have been shown to be sensitive to a variety of central nervous system white matter pathologies. Despite being sensitive, the lack of specificity limits the ability of these measures to differentiate the underlying pathology. Directional (axial and radial) diffusivities, measuring water diffusion parallel and perpendicular to the axonal tracts, have been shown to be specific to axonal and myelin damage in mouse models of optic nerve injury, including retinal ischemia and experimental autoimmune encephalomyelitis. The progression of Wallerian degeneration has also been detected using directional diffusivities after retinal ischemia. However, translating these findings to human optic nerve is technically challenging. The current status of diffusion MRI of human optic nerve, including imaging sequences and protocols, is summarized herein. Despite the lack of a consensus among different groups on the optimal sequence or protocol, increased mean diffusivity and decreased diffusion anisotropy have been observed in injured optic nerve from patients with chronic optic neuritis. From different mouse models of optic nerve injuries to the emerging studies on patients with optic neuritis, directional diffusivities show great potential to be specific biomarkers for axonal and myelin injury.
Dr. S.-K. Song, Biomedical MR Laboratory, Washington University School of Medicine, 4525 Scott Ave., St. Louis, MO 63110, USA. ssong@wusfl.edu
Classification:
6.9.5 Other (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
2.15 Optic nerve (Part of: 2 Anatomical structures in glaucoma)
