Transit time of a radionuclide bolus through inferior vena cava

The effect of an intrinsic block or extrinsic pressure on blood flow through the inferior vena cava (IVC) was studied after rapid injection of 99mTc-pertechnetate or 99mTc-phytate into the femoral vein. Peak-to-peak transit time (PTT) between the curves generated at IVC origin and over the cardiac blood pool was measured in twelve normal patients (PTT = 2.0 +/- 0.7 s) and six patients clinically suspected of circulatory impediment through the IVC (PTT = 3.0 to 30.0 s). PTT measurements augmented the information obtained from sequential scintiphotos of IVC circulation. It is felt that this may be a more objective parameter for follow-up of patients having a progressive, primary disease of this vessel.