Perfusion patterns in CT transit studies.

Transit studies consist of a rapid sequence of single cross-section CT scans performed during and following the bolus injection of contrast medium into the venous system. The low vascular volume of the brain leads to small changes in attenuation thereby reflecting the perfusion of vasculature. Studies were carried out following 45 examinations on 24 stroke patients and 15 tumor patients. Hypo-, normo- and hyperperfusion were observed in different tissue categories and related to specific tissue elements. The comparison of perfusion patterns with pre-contrast CT values and enhancement after 5 min elucidates cerebral hemodynamics in hypodense to hyperdense lesions with or without damage of the blood-brain barrier (BBB)