Comparison of impedance plethysmography with ascending venography for the diagnosis of proximal deep-vein thrombosis.

In a series of 56 patients with proximal lower-limb deep-vein thrombosis (DVT) diagnosed on ascending venography, impedance plethysmography (IPG) and Doppler ultrasound examinations were performed and the results compared. Both IPG and Doppler ultrasonography were highly sensitive for the diagnosis of proximal occlusive DVT, but considerably less sensitive for the potentially more dangerous proximal non-occlusive thrombosis. If, in the presence of clinically suspected DVT, these non-invasive investigations are both negative, ascending venography remains essential.