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September 1981

Extraction of Water Labeled With Oxygen 15 During Single-Capillary Transit: Influence of Blood Pressure, Osmolarity, and Blood-Brain Barrier Damage

Author Affiliations

From the Departments of Neurosurgery (Dr Go) and Nuclear Medicine (Ms Paans and Drs Vaalburg and Woldring), University of Groningen, the Netherlands. Dr Lammertsma is a Fellow of the Stichting Koningin Wilhelmina Fonds.

Arch Neurol. 1981;38(9):581-584. doi:10.1001/archneur.1981.00510090075009

• By external detection, the influence of arterial blood pressure (BP), osmolarity, and cold-induced blood-brain barrier damage was assessed on the extraction of water labeled with oxygen 15 during single-capillary transit in the rat. There was an inverse relation between arterial BP and extraction that was attributable to the influence of arterial BP on cerebral blood flow (CBF) and the relation between CBF and extraction. Neither arterial BP nor osmolarity of the injected bolus had any direct effect on extraction of water15O, signifying that the diffusional exchange component (determined by blood flow) of extraction greatly surpasses the convection flow contribution by hydrostatic or osmotic forces. Damage to the blood-brain barrier did not change its permeability to water.