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MR microscopy of perfused brain slices
S J Blackband1, J D Bui, D L Buckley
1Department of Neuroscience, University of Florida, Gainesville 32610, USA.
Abstract:
To study the origins of signal changes in clinical MRI we have previously studied isolated single neuronal cells by MR microscopy. To account for the extracellular environment of the cells, we have developed a prototype perfusion chamber for MR microimaging of perfused rat hippocampal brain slices. To demonstrate the utility of this model, brain slices were initially perfused in isotonic solutions and then subjected to osmotic perturbations via perfusate exchange with 20% hypertonic and 20% hypotonic solutions. In diffusion weighted images, signal intensity changes of +16(sigma(n-1) = 11)% (hypotonic) and -26(sigma(n-1) = 10)% (hypertonic) were observed. No significant variation in response was observed across the slice when several subregions were examined. These observations are consistent with the view that contrast changes are driven primarily by changes in the intra- and extracellular compartmentation of water. This is the first report of MR microimaging of the isolated brain slice. The technique will enable the correlation of MR microimaging measurements with microscopic changes using other modalities and techniques to provide a better understanding of signals in clinical MRI.
Insights
Researchers developed a novel MR microimaging technique for brain slices to understand clinical MRI signals. This method reveals how water movement between cell compartments affects MRI contrast.
Area of Science:
- Neuroscience
- Biophysics
- Medical Imaging
Background:
- Clinical MRI signal changes are not fully understood.
- Previous studies used isolated single neuronal cells.
- The extracellular environment's role requires further investigation.
Purpose of the Study:
- To develop a model for MR microimaging of perfused rat hippocampal brain slices.
- To investigate the origins of signal changes in clinical MRI.
- To correlate MR microimaging with microscopic changes.
Main Methods:
- Developed a prototype perfusion chamber for MR microimaging.
- Perfused rat hippocampal brain slices in isotonic solutions.
- Subjected slices to osmotic perturbations using hypertonic and hypotonic solutions.
Main Results:
- Observed signal intensity changes of +16% (hypotonic) and -26% (hypertonic) in diffusion-weighted images.
- No significant regional variation in response was noted across slices.
- Results suggest contrast changes are driven by water compartmentation.
Conclusions:
- This is the first report of MR microimaging of isolated brain slices.
- The technique provides insights into water movement and MRI signal origins.
- Enables correlation with other microscopic techniques for better clinical MRI understanding.