Suspected deep venous thrombosis: Is US of both legs necessary?

PURPOSE: The first purpose was to test the assumption that ultrasound (US) examination of the asymptomatic leg was unnecessary. The second was to confirm the absence of deep venous thrombosis (DVT) in patients with bilateral symptoms. MATERIALS AND METHODS: Four hundred eighty-eight patients were evaluated at a peripheral vascular laboratory for signs and symptoms of DVT. All patients then underwent bilateral color Doppler US of their leg veins. RESULTS: Ninety-four patients had no lower extremity symptoms. Of these, 73 had no DVT, 11 had unilateral DVT, and 10 had bilateral DVT. Of 245 patients with unilateral symptoms, 180 had no DVT, 44 had ipsilateral DVT, three had contralateral DVT, and 18 had bilateral DVT. Of 149 patients with bilateral symptoms, 114 had no DVT, 10 had unilateral DVT, and 25 had bilateral DVT. CONCLUSION: The frequent finding of bilateral DVT and unsuspected contralateral DVT in patients with unilateral symptoms, and the even more frequent finding of DVT in patients with bilateral symptoms, clearly indicates that both categories of patients need to be evaluated with bilateral US.