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Reversal of early diffusion-weighted magnetic resonance imaging abnormalities does not necessarily reflect tissue salvage in experimental cerebral ischemia.
- Source :
-
Stroke [Stroke] 2001 Oct; Vol. 32 (10), pp. 2362-9. - Publication Year :
- 2001
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Abstract
- Background and Purpose: Diffusion-weighted MRI (DWI) can detect early ischemic changes and is sometimes used as a surrogate neurological end point in clinical trials. Recent experimental stroke studies have shown that with brief periods of ischemia, some DWI lesions transiently reverse, only to recur later. This study examined the histological condition of the tissue during the period of DWI reversal.<br />Methods: Rats underwent 30 minutes of middle cerebral artery occlusion followed by reperfusion. DWI images were obtained during ischemia and 3 to 5 hours, 1 day, and 7 days later. MRI scans were compared with histology (5 hours, n=5; 7 days, n=5) with the use of neuronal (microtubule-associated protein 2 [MAP2]) and astrocytic (glial fibrillary acidic protein [GFAP]) markers and heat-shock protein 72 (HSP72).<br />Results: DWI abnormalities reversed 3 to 5 hours after ischemia onset but recurred at 1 day. Four animals showed complete reversal of the initial DWI hyperintensity, and 6 showed partial reversal. When the 5-hour DWI was completely normal, there was significant loss of MAP2 immunoreactivity, comprising approximately 30% of the initial DWI lesion. However, GFAP staining revealed morphologically normal astrocytes. HSP72 immunoreactivity at 5 hours was extensive and corresponded to the initial DWI lesion.<br />Conclusions: After brief ischemic periods, normalization of the DWI does not necessarily imply that the tissue is normal. Neurons already exhibit evidence of structural damage and stress. Normal GFAP staining suggests that other nonneuronal cell populations may partially compensate for altered fluid balances at the time of DWI reversal despite the presence of neuronal injury. These observations suggest that caution is warranted when relying solely on DWI for assessment of ischemic damage.
- Subjects :
- Animals
Astrocytes cytology
Astrocytes metabolism
Brain blood supply
Brain metabolism
Brain pathology
Brain Ischemia metabolism
Diffusion
Disease Models, Animal
Disease Progression
Glial Fibrillary Acidic Protein biosynthesis
HSP70 Heat-Shock Proteins biosynthesis
HSP72 Heat-Shock Proteins
Heat-Shock Proteins biosynthesis
Image Processing, Computer-Assisted
Male
Microtubule-Associated Proteins biosynthesis
Neurons metabolism
Neurons pathology
Predictive Value of Tests
Rats
Rats, Sprague-Dawley
Brain Ischemia diagnosis
Brain Ischemia pathology
Magnetic Resonance Imaging methods
Subjects
Details
- Language :
- English
- ISSN :
- 1524-4628
- Volume :
- 32
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Stroke
- Publication Type :
- Academic Journal
- Accession number :
- 11588327
- Full Text :
- https://doi.org/10.1161/hs1001.096058