Early diffusion evidence of retrograde transsynaptic degeneration in the human visual system

• Published in: Neurology Vol. 87; no. 2; p. 198
• Main Authors: Patel, Kevin R, Ramsey, Lenny E, Metcalf, Nicholas V, Shulman, Gordon L, Corbetta, Maurizio
• Format: Journal Article
• Language: English
• Published: United States 12.07.2016
• Subjects: Adult; Aged; Brain Ischemia - complications; Brain Ischemia - diagnostic imaging; Brain Ischemia - physiopathology; Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging; Female; Humans; Intracranial Hemorrhages - complications; Intracranial Hemorrhages - diagnostic imaging; Intracranial Hemorrhages - physiopathology; Longitudinal Studies; Male; Middle Aged; Neurodegenerative Diseases - diagnostic imaging; Neurodegenerative Diseases - etiology; Neurodegenerative Diseases - physiopathology; Prospective Studies; Stroke - complications; Stroke - diagnostic imaging; Stroke - physiopathology; Vision Disorders - diagnostic imaging; Vision Disorders - etiology; Vision Disorders - physiopathology; Visual Field Tests; Visual Pathways - diagnostic imaging; Visual Pathways - physiopathology; White Matter - diagnostic imaging; White Matter - physiopathology
• ISSN: 1526-632X
• DOI: 10.1212/WNL.0000000000002841

We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system after stroke. We performed a prospective longitudinal analysis of the sensitivity of DTI markers of optic tract health in 12 patients with postsynaptic visual pathway stroke, 12 stroke controls, and 28 healthy controls. We examined group differences in (1) optic tract fractional anisotropy (FA-asymmetry), (2) perimetric measures of visual impairment, and (3) the relationship between FA-asymmetry and perimetric assessment. FA-asymmetry was higher in patients with visual pathway lesions than in control groups. These differences were evident 3 months from the time of injury and did not change significantly at 12 months. Perimetric measures showed evidence of impairment in participants with visual pathway stroke but not in control groups. A significant association was observed between FA-asymmetry and perimetric measures at 3 months, which persisted at 12 months. DTI markers of RTD are apparent 3 months from the time of injury. This represents the earliest noninvasive evidence of RTD in any species. Furthermore, these measures associate with measures of visual impairment. DTI measures offer a reproducible, noninvasive, and sensitive method of investigating RTD and its role in visual impairment.