title: [Diffusion tensor imaging of the visual pathway in glaucomatous optic nerve atrophy].
abstract: In Germany more than one million inhabitants suffer from glaucoma, more than 100,000 are threatened with blindness because glaucoma is often diagnosed too late or not at all. Diagnosis and monitoring is usually carried out "only" by examination of the retina and not the whole visual pathway. However, the eye is just "the tip of the iceberg" of the actual visual pathway, which extends through the brain to the visual cortex. The interdisciplinary holistic assessment of the whole visual pathway in glaucoma is of crucial importance because glaucoma is a complex neurodegenerative disease. Subtypes, such as normal tension glaucoma (NTG), seem to originate from primary damage to the intracranial visual pathway with secondary retrograde retinal degeneration. Recent studies including glaucoma patients and healthy controls could show that diffusion tensor imaging with calculation of diffusion coefficients, i.e. fractional anisotropy (FA), mean and radial diffusivity (MD and RD) as markers of axonal integrity, provide the potential to assess the intracranial visual pathway with a high correlation to established ophthalmological examinations. In particular, calculation of FA maps of the visual pathway and accompanying voxel-based approaches, can be integrated into clinical routine. Thus, detection of glaucoma-related intracranial alterations, even in early stages of the disease, as well as differentiation of different glaucoma subtypes, is made possible. Furthermore, the diagnosis of normal tension glaucoma seems to be possible much earlier with these new imaging techniques compared to established ophthalmological work-up. Moreover, holistic imaging provides new insights into the pathophysiology of this form of glaucoma. This review article gives an overview of these novel magnetic resonance imaging techniques for assessment of the visual pathway in glaucomatous optic nerve atrophy and reveals the potential of an interdisciplinary approach.
authors.affiliation: Neuroradiologische Abteilung, Schwabachanlage 6 (Kopfklinik), Friedrich-Alexander Universität Erlangen-Nürnberg, 91054, Erlangen, Deutschland. tobias.engelhorn@uk-erlangen.de.
authors.forename: T
authors.initials: T
authors.lastname: Engelhorn
authors.affiliation: Neuroradiologische Abteilung, Schwabachanlage 6 (Kopfklinik), Friedrich-Alexander Universität Erlangen-Nürnberg, 91054, Erlangen, Deutschland.
authors.forename: M
authors.initials: M
authors.lastname: A Schmidt
authors.affiliation: Neuroradiologische Abteilung, Schwabachanlage 6 (Kopfklinik), Friedrich-Alexander Universität Erlangen-Nürnberg, 91054, Erlangen, Deutschland.
authors.forename: A
authors.initials: A
authors.lastname: Dörfler
authors.affiliation: Klinik für Augenheilkunde, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Deutschland.
authors.forename: G
authors.initials: G
authors.lastname: Michelson
mesh_terms: D056324:Diffusion Tensor Imaging; D005901:Glaucoma / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D033183:Interdisciplinary Communication; D000070516:Intersectoral Collaboration; D009896:Optic Atrophy / Q000000981:diagnostic imaging*; D018917:Optic Neuropathy, Ischemic / Q000000981:diagnostic imaging; D012307:Risk Factors; D014795:Visual Pathways / Q000000981:diagnostic imaging*
keywords: Diffusion tensor imaging; Diffusion weighted imaging; Glaucoma; Magnetic resonance imaging; Visual pathways