title: Dynamic dephasing changes in developing ischemic cerebral infarction in rats studied by Carr-Purcell T2 magnetic resonance imaging.
abstract: Carr-Purcell (CP) T(2) MRI with adiabatic pulses, acquired with varying interecho interval (tau(CP)), was used to study the time course of T(2) and relative dynamic-dephasing contrast in the rat brain. Exposure to 30 min of middle cerebral artery occlusion (MCAo) resulted in an irreversible increase in absolute CP-T(2) relaxation times. This was not associated with signal change in the relative dynamic-dephasing images, as computed by subtracting short tau(CP) CP-T(2) images from long tau(CP) images and normalizing for long tau(CP) images. A day after MCAo strong CP-T(2) hyperintensity and low apparent diffusion coefficient were evident in the striatum with a decline in relative dynamic-dephasing contrast. Low dynamic dephasing contrast prevailed in striatum until day 5 post-MCAo, returning to control levels with similar time course to normalizing T(2) and diffusion. The present results show a novel behavior of dynamic-dephasing contrast in poststroke brain tissue, providing data to assess the age of infarction in association to T(2) images.
authors.affiliation: Department of Biomedical NMR and National Bio-NMR Facility, A. I.Virtanen Institute, University of Kuopio, Kuopio, Finland.
authors.forename: Martin
authors.initials: M
authors.lastname: Kavec
authors.forename: Olli H J
authors.initials: OH
authors.lastname: Gröhn
authors.forename: Heidi I
authors.initials: HI
authors.lastname: Gröhn
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.forename: Risto A
authors.initials: RA
authors.lastname: Kauppinen
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000473:pathology*; D002544:Cerebral Infarction / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D017208:Rats, Wistar