title: Effects of cerebral ischemic and reperfusion on T2*-weighted MRI responses to brief oxygen challenge.
abstract: This study characterized the effects of cerebral ischemia and reperfusion on T2*-weighted magnetic resonance image (MRI) responses to brief oxygen challenge (OC) in transient (60 minutes) cerebral ischemia in rats. During occlusion, the ischemic core tissue showed no significant OC response, whereas the perfusion-diffusion mismatch tissue showed markedly higher percent changes relative to normal tissue. After reperfusion, much of the pixels with initial exaggerated OC responses showed normal OC responses, and the majority of these tissues were salvaged as defined by endpoint T2 MRI. The initial core pixels showed exaggerated OC responses after reperfusion, but the majority of the core pixels eventually became infarct, suggesting exaggerated OC responses do not necessarily reflect salvageable tissue. Twenty-four hours after stroke, basal T1 increased in the ischemic core. Oxygen challenge decreased T1 significantly in the core, indicative of the substantial increases in dissolved oxygen in the core as the result of hyperperfusion. We concluded that exaggerated T2*-weighted MRI responses to OC offer useful insight in ischemic tissue fates. However, exaggerated OC pixels are not all salvageable, and they exhibited complex dynamics depending on reperfusion status, hyperperfusion, and edema effects.
authors.affiliation: 1] Department of Research Imaging Institute, San Antonio, Texas, USA [2] Department of Ophthalmology, San Antonio, Texas, USA [3] Department of Radiology, University of Texas Health Science Center, San Antonio, Texas, USA.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shen
authors.affiliation: Department of Research Imaging Institute, San Antonio, Texas, USA.
authors.forename: Fang
authors.initials: F
authors.lastname: Du
authors.affiliation: Department of Research Imaging Institute, San Antonio, Texas, USA.
authors.forename: Shiliang
authors.initials: S
authors.lastname: Huang
authors.affiliation: 1] Department of Research Imaging Institute, San Antonio, Texas, USA [2] Department of Ophthalmology, San Antonio, Texas, USA [3] Department of Radiology, University of Texas Health Science Center, San Antonio, Texas, USA [4] South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, Texas, USA.
authors.forename: Timothy Q
authors.initials: TQ
authors.lastname: Duong
mesh_terms: D000818:Animals; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002546:Ischemic Attack, Transient / Q000150:complications / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000209:etiology / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology
chemical_list: D010100:Oxygen