Gamma-ray densitometry in the analysis of hemodynamic function.

An instrument has been developed to record contrast dilution curves by a noninvasive technique. Transthoracic roentgen density alterations are recorded by use of a solid state radiation detector array. A small amount of injected nonradioactive, radiopaque contrast material is distrubuted throughout the central circulation. The detector array positioned over the cardiopulmonary silhouette, records changes in density during the passage of the contrast material, and typical indicator dilution curves are transcribed. These curves reflect changes in blood flow distribution, vascular volume, cardiac function, and intrathoracic vascular shunts; and define the hemodynamic status of the circulatory system.