Diagnosis of deep vein thrombosis using duplex ultrasonography

Duplex ultrasonography is a safe, accurate, efficient, inexpensive, noninvasive diagnostic test for deep vein thrombosis (DVT). The sensitivity and specificity of this technique is comparable to venography in symptomatic patients in many studies. The diagnostic accuracy of this test can be further enhanced by serial studies. We report our experience with the use of this technique for study of 180 patients with clinically suspected DVT. Only 55 (30.6%) patients were confirmed to have DVT on duplex ultrasonography which illustrates the inaccuracy of bedside diagnosis of this potentially life-threatening condition. Almost all our DVT patients have proximal vein involvement, indicating that venous thrombosis usually do not cause signs or symptoms until they become large, occlusive and extend into the proximal veins. It is also observed in our study cohort that half of the patients with proximal vein thrombosis has incomplete recanalisation on follow-up study. None of them with normal study developed significant sequelae of untreated DVT, suggesting that it is safe to withhold treatment based on result of this non-invasive test. Duplex ultrasonography is the diagnostic modality of choice for suspected DVT in symptomatic patients and is an excellent substitute for conventional contrast venography.