Accuracy of Doppler ultrasound in clinically suspected venous thrombosis of the calf.

Doppler ultrasonic examinations and contrast phlebography were performed on 55 limbs of 43 patients with a clinical diagnosis of venous thrombosis of the calf and without phlebographic evidence of thrombosis above the knee. There was diagnostic concurrence of Doppler and venographic evaluations in 46 of 55 limbs studied. There was only one instance of a false-negative diagnosis by Doppler examination. Of the eight false-positive Doppler examination findings, an alternate clinical diagnosis affecting venous flow in the calf was evident in six patients. The diagnostic importance of augmentation of flow velocity of the posterior tibial vein upon release of compression of the calf is emphasized. A normal Doppler examination finding may accurately exclude significant deep venous disease in a patient with clinical manifestations of venous thrombosis in the calf.