The Reliability of Venous Duplex Ultrasound and Clinical Findings for the Diagnosis of Lower Extremity Deep Venous Thrombosis.

INTRODUCTION AND OBJECTIVES: The gold standard for the diagnosis of lower extremity deep vein thrombosis (DVT) is reported to be venous duplex ultrasound (VDU) because it is noninvasive, sensitive, relatively inexpensive, and can be performed at a patients bedside. The objective of this investigation was to measure agreement in the interpretation of VDU between multiple medical specialties.

METHODS: Agreement among different physicians who typically interpret VDU images were examined. The physicians were from multiple specialties and included 3 vascular surgeons (VS), 3 emergency medicine physicians (EM), and 1 radiologist. Four complete VDU imaging tests originally obtained for suspected DVT and used for the diagnosis were organized onto a computer program and independently reviewed by the seven physicians. The physicians were asked to review and interpret the VDU imaging test and note whether the test was positive or negative for thrombosis.

RESULTS: For the first case, 2 physicians diagnosed a positive examination while 5 physicians diagnosed a negative examination. For the second case, 4 physicians diagnosed a positive examination while 3 physicians diagnosed a negative examination. For the third case, 4 physicians diagnosed a positive examination while 3 physicians diagnosed a negative examination. For the fourth case, 6 physicians diagnosed a positive examination, while 1 physician diagnosed a negative examination. These findings resulted in an intraclass correlation coefficient (ICC) value of 0.292 indicating a fair degree of agreement.

CONCLUSIONS: We think these findings indicate that VDU may lack the diagnostic accuracy to be considered a gold standard for the diagnosis of lower extremity DVT. We also think this finding highlights the importance of appreciating that VDU is a dynamic evaluation reliant on the clinical knowledge and technical skills of whoever is performing the test. Reviewing static imaging alone may not provide enough information to make the diagnosis consistently.