Validation of an inexpensive B-mode ultrasound device for detection of deep vein thrombosis

Objective: To validate a portable, inexpensive, real-time, B-mode ultrasound device compared with duplex ultrasound in the detection of proximal lower extremity deep vein thrombosis in hospitalized patients clinically suspected of having deep vein thrombosis. Design: Prospective cohort study. Setting: Tertiary care community teaching hospital. Patients: Medical-surgical hospitalized patients undergoing duplex ultrasonography for clinically suspected lower extremity deep vein thrombosis. Interventions: Hospitalized patients who underwent duplex ultrasound examinations were enrolled in the study. Blinded from the duplex ultrasound results, the investigators utilized the study ultrasound device to perform compression ultrasonography of the common femoral, superficial femoral, and popliteal veins within 48 h of the duplex examinations. The results of the study ultrasound device were recorded as normal (compressible) or abnormal (noncompressible). Results: Of the 198 lower limbs evaluated, duplex ultrasonography documented 34 proximal lower extremity deep vein thrombi. The study ultrasound device detected 32 of the 34 proximal thrombi detected by duplex ultrasonography. One false-positive result of an examination occurred with the study ultrasound device. Compared with duplex ultrasonography, the study ultrasound device had a sensitivity of 94%, specificity of 99%, positive predictive value of 97%, and negative predictive value of 98%. Conclusions: The results of this investigation document that the study ultrasound device has an acceptable sensitivity specificity and diagnostic accuracy for clinical use in detection of proximal lower extremity deep vein thrombosis. Further evaluation and validation of this ultrasound device are warranted.