Dynamic computed tomography time--density study of normal human tissue after intravenous contrast administration.
Dynamic sequential 3-second CT scans of human abdominal organs were obtained after an intravenous bolus injection of diatrizoate. Time--density curves obtained from the renal cortex and medulla were compared with similar curves obtained from the aorta, inferior vena cava, muscle, and normal liver. CT scans revealed the changes in density produced by the contrast agent reflecting the differential phases of blood flow in the aorta and inferior vena cava. Changes in density in the liver, muscle, and the cortex and medulla of the kidney undoubtedly were related to vascular and extravascular contrast agent. Renal cortical density increased rapidly after bolus administration and peaked approximately 6 seconds after the peak in aortic contrast and slowly declined over the observation period. Renal medullary density increased slowly and at first remained significantly below the cortex but was slightly above cortical values after 30 seconds. These studies indicate that dynamic CT scanning is an effective way of monitoring the contrast media pharmacokinetics within tissue and that human renal function can be monitored and evaluated by using this technique.