title: Transient increase of fractional anisotropy in reversible vasogenic edema.
abstract: Brain vasogenic edema, involving disruption of the blood-brain barrier, is a common pathological condition in several neurological diseases, with a heterogeneous prognosis. It is sometimes reversible, as in posterior reversible encephalopathy syndrome, but often irreversible and our current clinical tools are insufficient to reveal its reversibility. Here, we show that increased fractional anisotropy in magnetic resonance imaging is associated with the reversibility of vasogenic edema. Spontaneously, hypertensive rats-stroke prone demonstrated posterior reversible encephalopathy syndrome-like acute encephalopathy in response to high-dose cyclosporine A treatment; the deteriorating neurological symptoms and worsening scores in behavioral tests, which were seen in acute phase, dissappered after recovery by cessation of cyclosporine A. In the acute phase of encephalopathy, the fractional anisotropy and apparent diffusion coefficient increased in areas with IgG leakage. This increase of fractional anisotropy occurred in the absence of demyelination: fluid leakage into the myelinated space increased the axial, but not the radial, diffusivity, resulting in the increased fractional anisotropy. This increased fractional anisotropy returned to pre-encephalopathy values in the recovery phase. Our results highlight the importance of the fractional anisotropy increase as a marker for the reversibility of brain edema, which can delineate the brain areas for which recovery is possible.
authors: Department of Neurology, University of New Mexico, Albuquerque, USA ShKimura@salud.unm.edu skimura@ped.med.osaka-u.ac.jp.
authors: Shihoko
authors: S
authors: Kimura-Ohba
authors: Department of Neurology, University of New Mexico, Albuquerque, USA.
authors: Yi
authors: Y
authors: Yang
authors: Department of Neurology, University of New Mexico, Albuquerque, USA.
authors: Jeffrey
authors: J
authors: Thompson
authors: Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, USA.
authors: Tomonori
authors: T
authors: Kimura
authors: Department of Neurology, University of New Mexico, Albuquerque, USA.
authors: Victor M
authors: VM
authors: Salayandia
authors: Department of Neurology, University of New Mexico, Albuquerque, USA.
authors: Melissa
authors: M
authors: Cosse
authors: BRaIN Imaging Center and College of Pharmacy, University of New Mexico, Albuquerque, USA.
authors: Yirong
authors: Y
authors: Yang
authors: Department of Neurology, University of New Mexico, Albuquerque, USA BRaIN Imaging Center and College of Pharmacy, University of New Mexico, Albuquerque, USA.
authors: Laurel O
authors: LO
authors: Sillerud
authors: Department of Neurology, University of New Mexico, Albuquerque, USA Department of Neurosciences, University of New Mexico, Albuquerque, USA Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA.
authors: Gary A
authors: GA
authors: Rosenberg
mesh_terms: D000818:Animals; D016880:Anisotropy; D001522:Behavior, Animal / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging; D001929:Brain Edema / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000473:pathology; D016572:Cyclosporine / Q000008:administration & dosage / Q000633:toxicity; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004195:Disease Models, Animal; D007074:Immunoglobulin G / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D054038:Posterior Leukoencephalopathy Syndrome / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000473:pathology; D011918:Rats, Inbred SHR
chemical_list: D007074:Immunoglobulin G; D016572:Cyclosporine
keywords: Blood-brain barrier; brain vasogenic edema; diffusion tensor imaging; fractional anisotropy; posterior reversible encephalopathy syndrome