Stroke is a leading cause of morbidity and mortality in the United States and throughout the world. The purpose of the proposed research project is to characterize in vivo brain parenchymal changes in a rat model of focal stroke with reperfusion using magnetic resonance (MR) techniques. Functional assessment of the ischemic region will be carried out using a novel technique for noninvasive quantitative MR imaging of tissue perfusion, which will be used to acquire time-resolved perfusion images following acute focal stroke and subsequent reperfusion. Further characterization will be carried out using various other types of MR imaging methods which yield complementary types of tissue contrast, and comparison will be made using histopathologic analysis in the chronic stage as a """"""""gold standard' of brain infarction and recovery. These techniques will be used to determine the MR correlates of the """"""""ischemic penumbra"""""""", namely the regions of potentially reversible ischemia injury. Once the MR correlates are determined, the effects of various therapies aimed at reducing tissue damage in brain ischemia can be readily tested using this model. Because MR techniques are noninvasive, this approach is immediately applicable to the investigation and therapy of acute stroke in humans. For example, the accurate determination of potentially salvageable brain tissue in a patient with acute stroke would improve the risk-benefit ratio for thrombolytic therapy or other therapies which carry significant risks. To this end, technical development of the MR perfusion technique for use in humans will take place simultaneously with the rat studies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08NS001668-05
Application #
2460450
Study Section
NST-2 Subcommittee (NST)
Program Officer
Jacobs, Tom P
Project Start
1993-08-01
Project End
1998-07-31
Budget Start
1997-08-01
Budget End
1998-07-31
Support Year
5
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Neurology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Ances, B M; Greenberg, J H; Detre, J A (2001) The effects of graded hypercapnia on the activation flow coupling response due to forepaw stimulation in alpha-chloralose anesthetized rats. Brain Res 911:82-8
Alsop, D C; Detre, J A; Grossman, M (2000) Assessment of cerebral blood flow in Alzheimer's disease by spin-labeled magnetic resonance imaging. Ann Neurol 47:93-100
Ances, B M; Detre, J A (2000) Laser Doppler imaging of changes in cerebral blood flow during acute carotid occlusion. J Clin Laser Med Surg 18:131-7
Gonzalez-At, J B; Alsop, D C; Detre, J A (2000) Cerebral perfusion and arterial transit time changes during task activation determined with continuous arterial spin labeling. Magn Reson Med 43:739-46
Ances, B M; Greenberg, J H; Detre, J A et al. (2000) Acute carotid occlusion alters the activation flow coupling response to forepaw stimulation in a rat model. Stroke 31:955-60
Ances, B M; Greenberg, J H; Detre, J A (1999) Laser doppler imaging of activation-flow coupling in the rat somatosensory cortex. Neuroimage 10:716-23
Detre, J A; Samuels, O B; Alsop, D C et al. (1999) Noninvasive magnetic resonance imaging evaluation of cerebral blood flow with acetazolamide challenge in patients with cerebrovascular stenosis. J Magn Reson Imaging 10:870-5
Alsop, D C; Detre, J A (1998) Multisection cerebral blood flow MR imaging with continuous arterial spin labeling. Radiology 208:410-6
Detre, J A; Ances, B M; Takahashi, K et al. (1998) Signal averaged laser Doppler measurements of activation-flow coupling in the rat forepaw somatosensory cortex. Brain Res 796:91-8
Detre, J A; Maccotta, L; King, D et al. (1998) Functional MRI lateralization of memory in temporal lobe epilepsy. Neurology 50:926-32

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