Magnetic resonance imaging detection of multiple ischemic injury produced in an adult rat model of minor stroke followed by mild transient cerebral ischemia.
OBJECTIVE
To determine whether cumulative brain damage produced adjacent to a minor stroke that is followed by a mild transient ischemia is detectable with MRI and histology, and whether acute or chronic recovery between insults influences this damage.


METHODS
A minor photothrombotic (PT) stroke was followed acutely (1-2 days) or chronically (7 days) by a mild transient middle cerebral artery occlusion (tMCAO). MRI was performed after each insult, followed by final histology.


RESULTS
The initial PT produced small hyperintense T2and DW infarct lesions and peri-lesion regions of scattered necrosis and modestly increased T2. Following tMCAO, in a slice and a region adjacent to the PT, a region of T2augmentation was observed when recovery between insults was acute but not chronic. Within the PT slice, a modest region of exacerbated T2change proximate to the PT was also observed in the chronic group. Corresponding histological changes within regions of augmented T2included increased vacuolation and cell death.


CONCLUSIONS
Within regions adjacent to an experimental minor stroke, a recurrence of a mild transient cerebral ischemia augmented T2above increases produced by tMCAO alone, reflecting increased damage in this region. Exacerbation appeared broader with acute versus chronic recovery between insults.
Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3280 Hospital Dr, NW, Calgary, T2N 2T8, Canada. utuor@ucalgary.ca.
Ursula I
UI
Tuor
Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3280 Hospital Dr, NW, Calgary, T2N 2T8, Canada.
Min
M
Qiao
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D016923:Cell Death; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013696:Temperature; D013927:Thrombosis
Animals; Cell death; Ischemic attack; Magnetic resonance imaging; Stroke; Transient