Radionuclide venography: two stage--flow and equilibrium technique using 99mTc pertechnetate, and 99mTc RBC labelled "in vivo".

A new method involves 2 stages: 1st, injection of three 10 ml boluses of 99mTc-pertechnetate through a dorsal vein of the foot with recording of 3 separate dynamic studies of venous flow in the calf, thigh and pelvis; and 2nd, static equilibrium venography (EV), which can be completed 15 min later after 99mTc-RBC labelling in vivo. The method was performed in 100 patients with suspected DVT. Due to the large pertechnetate bolus followed with 20-40 ml flush of normal saline, the flow study provides a significant improvement in filling of major calf veins, which makes this technique more similar to contrast phlebography. The flow study was found much more sensitive than EV, especially for calf DVT. However, EV, providing information about the unaffected leg, plays an important complementary role when the study is negative for DVT. In conclusion, both stages are recommended for routine examination of patients referred with suspected DVT.