Thromboembolic disease.

In 52 patients with pulmonary embolism, the deep venous circulation of the lower extremities and the pulmonary arterial blood flow were studied with albumin macroaggregates labeled with technetium-99m. A gamma camera with a data processor was used for this study. At the beginning, the perfusion lung scintigrams were abnormal in all the patients, 42 of them also had abnormal phlebograms and in half of them the perfusion by lung scintigram became normal when the phlebograms were obtained. These findings establish the high incidence of deep thrombophebitis in the legs of the patients with pulmonary embolism and indicate that the leg is of the most important 'thrombi factory' and that the deep venous circulation of the extremities should be studied to determine the primary cause of the pulmonary embolism.