Interpretation of99mTc Superior Vena Cavograms and Results of Studies in 92 Patients

Superior vena cavography, using 99mTc, was performed in 92 patients including 45 with superior vena caval obstruction and 47 normal subjects. As an aid in the intepretation of findings seen on the 99mTc vena cavogram, 27 patients with obstruction also underwent contrast medium vena cavography. Normal variants seen on the 99mTc cavogram included collateral pathways accompanying superior vena caval obstruction, observation of the pulmonary circulation phase, and determination of transit time from the antecubital vein to the right heart. Radionuclide vena cavography is suggested as a simple safe procedure for initial screening for superior vena caval obstruction and follow-up studies.