title: Chronic brain tissue remodeling after stroke in rat: a 1-year multiparametric magnetic resonance imaging study.
abstract: Rats subjected to 2h of transient middle cerebral artery occlusion were studied temporally over 1 year by magnetic resonance imaging (MRI) and behavioral testing. Multiparameter MRI measures of T(2), T(1), T(1) in the presence of off-resonance saturation of the bound proton signal (T(1sat)), apparent diffusion coefficient (ADC) and susceptibility-weighted imaging (SWI) were obtained at 1 day, 1, 2, 3 and 4 weeks, and 3, 6, 9 and 12 months post-ischemia. Regions of interest included: ischemic core (damaged both at 1 day and later); new lesion (normal at 1 day, but damaged later); and recovery (damaged at 1 day, but normal later) areas. Hematoxylin and eosin, Prussian blue and ED-1, a monoclonal antibody murine macrophage marker, stainings were performed for histological assessment. Core area T(2) and ADC values increased until ~6 months, and T(1) and T(1sat) until ~12 months. New lesion area MRI parameter values increased until ~6 months (T(2), T(1) and ADC), or ~1 year (T(1sat)). Lesion area was largest at 1day (mean±SD: 37.0±13.7mm(2)) and smallest at 1 year (18.1±10.5mm(2)). Recovery area was largest at 3 weeks (8.9±3.8mm(2)) and smallest at 1year (6.4±3.3mm(2)). The ipsilateral/contralateral ventricle area ratio was 0.7±0.2 at 1 day and increased significantly at 1 year (2.4±0.7). Iron-laden macrophages, histologically confirmed at 1 year, were detected in the lesion borders by SWI at 3, 6, 9 and 12 months. Our data indicate that MRI detectable changes of ischemia-damaged brain tissue continue for at least 1 year post-ischemia.
authors.affiliation: Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Kishor
authors.initials: K
authors.lastname: Karki
authors.forename: Robert A
authors.initials: RA
authors.lastname: Knight
authors.forename: Li Hong
authors.initials: LH
authors.lastname: Shen
authors.forename: Alissa
authors.initials: A
authors.lastname: Kapke
authors.forename: Mei
authors.initials: M
authors.lastname: Lu
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Michael
authors.initials: M
authors.lastname: Chopp
mesh_terms: D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000150:complications / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D017352:Echo-Planar Imaging; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008279:Magnetic Resonance Imaging; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D020521:Stroke / Q000473:pathology*