Isotope phlebography in the study of lower extremity venous thrombosis.

Isotope phlebography is performed using 99mTc as pertecnetate, macroaggregates of albumin (MAA) or microspheres of albumin (MISA). The isotope is injected at a dose of 6-10 mCi into the dorsal foot veins. The area studied begins at the knee and is followed successively by the groin, the iliac area and the region of the IVC. A pulmonary scan is performed when MAA or MISA are used. Our method has proven to be reliable in showing 1) thrombosis of the veins of the groin and iliac area, which appear as a 'non visualisation' of the venous tract, 2) delayed transit time of the isotope, 3) visualisation of the superficial circulation (changes and irrgularities). The association of istope phlebography with pulmonary scan is useful for evaluating the femoral-iliac and the vena caval system and for detecting the presence of pulmonary embolism.