(Stroke. 1999;30:1263-1270.)
© 1999 American Heart Association, Inc.
Original Contributions |
From the Department of Medical Physics and Bioengineering, University College London (G.S.P., D.L.T., R.J.O.), and The Royal College of Surgeons Unit of Biophysics, Institute of Child Health, University College London Medical School, (D.L.T., F.C., M.F.L., M.D.K., D.G.G.), London, UK.
Correspondence to Gaby Pell, RCS Unit of Biophysics, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. E-mail g.pell{at}medphys.ucl.ac.uk
Background and PurposeExisting methods for the quantitative measurement of the changing cerebral blood flow (CBF) during reperfusion suffer from poor spatial or temporal resolution. The aim of this study was to implement a recently developed MRI technique for quantitative perfusion imaging in a gerbil model of reperfusion. Flow-sensitive alternating inversion recovery (FAIR) is a noninvasive procedure that uses blood water as an endogenous tracer.
MethodsBilateral forebrain ischemia of 4 minutes' duration was induced in gerbils (n=8). A modified version of FAIR with improved time efficiency was used to provide CBF maps with a time resolution of 2.8 minutes after recirculation had been initiated. Quantitative diffusion imaging was also performed at intervals during the reperfusion period.
ResultsOn initiating recirculation after the transient period of ischemia, the FAIR measurements demonstrated either a symmetrical, bilateral pattern of flow impairment (n=4) or an immediate side-to-side difference that became apparent with respect to the cerebral hemispheres in the imaged slice (n=4). The flow in each hemisphere displayed a pattern of recovery close to the preocclusion level or, alternatively, returned to a lower level before displaying a delayed hypoperfusion and a subsequent slow recovery. The diffusion measurements during this latter response suggested the development of cell swelling during the reperfusion phase in the striatum.
ConclusionsThe CBF during the reperfusion period was monitored with a high time resolution, noninvasive method. This study demonstrates the utility of MRI techniques in following blood flow changes and their pathophysiological consequences.
Department of Neurology, University of New Mexico School of Medicine, Albuquerque, New Mexico
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