A Novel Proposal for an Index for Regional Cerebral Perfusion Pressure – A Theoretical Approach Using Fluid Dynamics

Cerebral blood flow (CBF) / cerebral blood volume (CBV) ratio derived by [ 15 O] H 2 O/ CO 2 and CO positron emission tomography (PET) examination has been used empirically as an index for cerebral perfusion pressure (CPP). However, this equation lacks a theoretical basis and furthermore, has not been confirmed to be proportionate to CPP, as direct measurement of local CPP is not practical. We have developed a new index for CPP using the Poiseuille equation based on a simple model. Our model suggests that CBF/CBV 2 is proportionate to CPP and that it is mathematically a more accurate index than CBF/CBV.