Brain tissue elasticity and CSF elastance

In the analysis of the pressure-volume relationship of the intracranial system, the concept of brain elastance, sometimes called tissue elastance or CSF elastance, is often used. It is generally designated as Ecsf and is calculated as the slope of the pressure-volume curve of the system. Variations in Ecsf are related to, for example, changes in the buffering capacity of the system which, however, could be influenced by the cerebral vascular volume, compressibility of the meningeal membranes, and compressibility of the subpial brain tissue. Our interest is in isolating the effect of controlled changes in the intracranial system with changes in the subpial tissue only. Here we discuss the measurement of brain tissue elasticity and describe two experimental conditions in which simultaneous measurements showed distinct differences between the behaviour of the system CSF elastance and brain tissue elastic behaviour.