Measurement of canine cerebral oedema using vector impedance methods.

The introduction of distilled water in vitro into brain tissue increases the water content of the cerebral white matter. The increase in water content for canine white matter may be predicted from impedance measurements on the tissue and the empirical equations determined in this study. However, the equations may only be valid for osmotic oedema induced in vitro as the behaviour of impedance related parameters is dependent on the type of oedema induced. The tissue volume measured with this technique may be reduced by the use of a smaller diameter probe. New equations relating impedance parameters to the water content for this probe and more accurate instrumentation may be required.