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Journal of Biomedicine and Biotechnology
Volume 2011 (2011), Article ID 318346, 8 pages
http://dx.doi.org/10.1155/2011/318346
Research Article

Blood-Oxygenation-Level-Dependent-(BOLD-) Based R2 MRI Study in Monkey Model of Reversible Middle Cerebral Artery Occlusion

Department of Radiology, General Hospital, Tianjin Medical University, 154 Anshan Road Heping District Tianjin 300052, China

Received 10 September 2010; Revised 25 November 2010; Accepted 30 December 2010

Academic Editor: Andrea Vecchione

Copyright © 2011 Jing Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. To investigate the value of BOLD-based reversible transverse relaxation rate (R2′) MRI in detecting ischemic penumbra (IP) in a monkey model of reversible middle cerebral artery occlusion (MCAO) and time evolution of relative R2′ (rR2′) in infarcted core, IP, and oligemia. Materials and Methods. 6 monkeys were used to make MCAO by the microcatheter method. MR scans were performed at 0 h (1 h after MCAO), 1 h, 3 h, 6 h, 12 h, 24 h, and 48 h after reperfusion. R2′ was calculated using quantitative T2 and T2 maps. Ischemic area was subdivided into infracted core, IP and oligemia. rR2′ was calculated respectively. Results. Reversible MCAO model for 4/6 monkeys was made successfully. rR2′ values were significantly different at each time point, being highest in oligemia followed by IP and infarcted core ( 𝑃 < . 0 5 ). With reperfusion time evolution, rR2′ in infarcted core showed a decreased trend: sharply decreased within 6 hours and maintained at 0 during 6–48 hours ( 𝑃 < . 0 5 ). rR2′ values in IP and oligemia showed similar increased trend: sharply increased within 6 hours, maintained a plateau during 6–24 hours, and slightly increased until 48 hours. Conclusion. BOLD-based R2′ MRI can be used to describe changes of cerebral oxygen extract in acute ischemic stroke, and it can provide additional information in detecting IP. The time evolution rR2′ in infarcted core, IP, and oligemia is in accordance with the underlying pathophysiology.