Noninvasive detection of deep venous thrombosis. A critical evaluation.

The problems associated with deep venous thrombosis are well established. Correct diagnosis cannot be made by clinical examination; therefore, an objective test for accurate assessment becomes necessary. Contrast venography is recognized as the gold standard examination. However, the disadvantages of venography including radiation, dye exposure, and cost are also well recognized. These disadvantages have led to the development of the noninvasive studies. To evaluate Duplex B-mode ultrasound, Doppler, and air plethysmography, a retrospective review of patients referred to the vascular laboratory for evaluation of deep venous thrombosis was performed. From June 1984 until June 1987, 1,870 patients were examined in the laboratory. Forty eight of these patients underwent all three noninvasive tests as well as contrast venography. There were 16 men and 32 women with a mean age of 60. A total of 50 limbs was examined in these patients. The noninvasive tests had the following sensitivities as compared with venography: Doppler 71 per cent, air plethysmography 71 per cent, and Duplex B-mode ultrasound 95 per cent. These results were statistically significant at P less than 0.05. The specificities for Doppler, air plethysmography, and Duplex B-mode ultrasound were 90 per cent, 83 per cent, and 100 per cent, respectively. These results were also statistically significant at P less than 0.02. Based on these findings, we conclude that Duplex B-mode ultrasound is a superior noninvasive examination as compared with air plethysmography or Doppler, and is a reliable, economical, and efficient substitute for contrast venography.