Magnetic resonance imaging indicators of blood-brain barrier and brain water changes in young rats with kaolin-induced hydrocephalus
| Autor: | Marc R. Del Bigio, Tanya L Kemp-Buors, Angela E. Schellenberg, Richard Buist, Ili Slobodian |
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| Rok vydání: | 2011 |
| Předmět: |
medicine.medical_specialty
Pathology Neurology endothelium Endothelium tissue water Blood–brain barrier lcsh:RC346-429 030218 nuclear medicine & medical imaging magnetic resonance 03 medical and health sciences Cellular and Molecular Neuroscience 0302 clinical medicine Developmental Neuroscience medicine skin and connective tissue diseases lcsh:Neurology. Diseases of the nervous system density medicine.diagnostic_test business.industry Research Magnetic resonance imaging General Medicine medicine.disease Hydrocephalus medicine.anatomical_structure Ventricle Permeability (electromagnetism) Cerebral ventricle sense organs business 030217 neurology & neurosurgery |
| Zdroj: | Fluids and Barriers of the CNS Fluids and Barriers of the CNS, Vol 8, Iss 1, p 22 (2011) |
| ISSN: | 2045-8118 |
| DOI: | 10.1186/2045-8118-8-22 |
| Popis: | Background Hydrocephalus is associated with enlargement of cerebral ventricles. We hypothesized that magnetic resonance (MR) imaging parameters known to be influenced by tissue water content would change in parallel with ventricle size in young rats and that changes in blood-brain barrier (BBB) permeability would be detected. Methods Hydrocephalus was induced by injection of kaolin into the cisterna magna of 4-week-old rats, which were studied 1 or 3 weeks later. MR was used to measure longitudinal and transverse relaxation times (T1 and T2) and apparent diffusion coefficients in several regions. Brain tissue water content was measured by the wet-dry weight method, and tissue density was measured in Percoll gradient columns. BBB permeability was measured by quantitative imaging of changes on T1-weighted images following injection of gadolinium diethylenetriamine penta-acetate (Gd-DTPA) tracer and microscopically by detection of fluorescent dextran conjugates. Results In nonhydrocephalic rats, water content decreased progressively from age 3 to 7 weeks. T1 and T2 and apparent diffusion coefficients did not exhibit parallel changes and there was no evidence of BBB permeability to tracers. The cerebral ventricles enlarged progressively in the weeks following kaolin injection. In hydrocephalic rats, the dorsal cortex was more dense and the white matter less so, indicating that the increased water content was largely confined to white matter. Hydrocephalus was associated with transient elevation of T1 in gray and white matter and persistent elevation of T2 in white matter. Changes in the apparent diffusion coefficients were significant only in white matter. Ventricle size correlated significantly with dorsal water content, T1, T2, and apparent diffusion coefficients. MR imaging showed evidence of Gd-DTPA leakage in periventricular tissue foci but not diffusely. These correlated with microscopic leak of larger dextran tracers. Conclusions MR characteristics cannot be used as direct surrogates for water content in the immature rat model of hydrocephalus, probably because they are also influenced by other changes in tissue composition that occur during brain maturation. There is no evidence for widespread persistent opening of BBB as a consequence of hydrocephalus in young rats. However, increase in focal BBB permeability suggests that periventricular blood vessels may be disrupted. |
| Databáze: | OpenAIRE |
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