Cerebral blood volume and water extraction from cerebral parenchyma by hyperosmolar contrast media.

The attenuation coefficients of cerebral parenchyma and systemic blood were simultaneously measured at varying times after injection of two contrast agents with differing osmolarities. Cerebral parenchyma was in fact denser than the theory would predict. The osmolarity of the iodinated contrast agents seems to play only a very minor part. However, liposolubility could perhaps explain the leakage of iodine across the BBB and thus the increase in the attenuation coefficient of cerebral parenchyma.