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Postmortem diffusion of autoradiographic blood flow tracers
J H Greenberg1, C LoBrutto, K M Lombard
1Department of Neurology, Cerebrovascular Research Center, University of Pennsylvania, 429 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6063, USA. greenberg@cvrc.med.upenn.edu
Brain Research
|October 20, 1999
Summary
Rapid freezing is crucial for accurate brain blood flow measurements using [14C]iodoantipyrine autoradiography. Delays cause postmortem diffusion, degrading image quality and local cerebral blood flow data.
Area of Science:
- Neuroscience
- Radiochemistry
Background:
- Autoradiography is used to measure local cerebral blood flow.
- [14C]iodoantipyrine is a common tracer due to its properties.
- Postmortem diffusion of the tracer can cause errors in measurement.
Purpose of the Study:
- To measure the diffusion coefficient of [14C]iodoantipyrine in brain tissue.
- To assess the impact of postmortem diffusion on cerebral blood flow autoradiography.
- To emphasize the need for rapid tissue freezing.
Main Methods:
- Measured the bulk diffusion coefficient of [14C]iodoantipyrine in vitro.
- Measured cerebral blood flow in anesthetized rats using [14C]iodoantipyrine.
- Utilized a novel freeze-capture device for rapid postmortem tissue freezing.
Main Results:
- The diffusion coefficient for [14C]iodoantipyrine in brain tissue was determined to be 2.1 x 10(-6) cm(2)/s.
- Autoradiograms revealed significant heterogeneity in cerebral blood flow.
- Computer simulations demonstrated that tracer diffusion significantly degrades image quality.
Conclusions:
- Rapid postmortem freezing is essential to prevent tracer diffusion artifacts.
- Accurate measurement of local cerebral blood flow requires minimizing postmortem diffusion.
- The developed freeze-capture technique enhances the reliability of autoradiographic studies.