Evaluation of recurrent deep venous thrombosis using colour duplex scanning--comparison with venography.

Recurrent deep venous thrombosis (DVT) is clinically difficult to evaluate and diagnosis is often unreliable. In this study we compared colour duplex scanning and venography in 150 limbs (133 patients) with recurrent DVT and in 20 normal limbs. A 7.5 mHz linear probe colour duplex was used. Venography was unclear or did not show DVT in 10% of limbs with chronic DVT and in 20% of limited/initial DVTs. Also, venography did not show 10.44% iliac/femoral thrombi, 9.73% popliteal thrombi and 4.08% thrombi below the knee. In total venography did not reveal 14.7% of the sites of recurrent DVT documented by colour duplex. In conclusion colour duplex is effective in detecting recurrent DVT and, according to these preliminary data, may reveal thrombosis sites not seen by venography.