Venous duplex imaging for the diagnosis of acute deep venous thrombosis

Acute deep venous thrombosis (DVT) continues to be a common clinical problem requiring objective evaluation. Hemodynamic testing for acute DVT has been popular, but is inadequate for evaluating asymptomatic patients and symptomatic patients with isolated calf vein thrombi. Venous duplex imaging (VDI) has rapidly gained in popularity, and is generally accepted to be the noninvasive technique of choice for the evaluation of patients with acute DVT. Twenty-five reports evaluate gray-scale venous duplex imaging versus ascending phlebography in 2,781 symptomatic patients. The sensitivity for proximal DVT and calf DVT is 96 and 80%, respectively. Seven reports review the use of VDI for surveillance in 857 asymptomatic patients, with an overall sensitivity of 76% for proximal DVT and of 11% for isolated calf vein thrombosis. The results of color-flow duplex appear to be somewhat better; however, the numbers are considerably smaller. The results for identification of calf vein thrombosis in asymptomatic surveillance patients continue to be poor. VDI appears to be the best noninvasive diagnostic test for acute DVT, and may challenge ascending phlebography as the best diagnostic test for proximal DVT in symptomatic patients, although it will miss 20% of isolated calf DVT. VDI appears to be the best noninvasive screening technique for high-risk asymptomatic patients under surveillance; however, additional correlative studies with ascending phlebography are required. The addition of color Doppler images appears to have improved results, although these higher sensitivities may be the consequence of improved experience as much as the addition of color to the image.