Contrast Venography, the Gold Standard for the Diagnosis of Deep-Vein Thrombosis: lmprovement in Observer Agreement

Abstract

SummaryTo determine whether the Rabinov-Paulin or the long-leg venography technique should be preferred in the diagnostic management of patients with clinically suspected deep-vein thrombosis, two independent experienced radiologists blindly assessed two different series of venograms of consecutive outpatients with clinically suspected deep-vein thrombosis. Venograms were obtained from two outpatient clinics of primary referral centres. In one centre the venograms were performed according to the technique of Rabinov and Paulin with the use of 100 ml of radiographic material and spot films of the calf, popliteal and more proximal veins. In the other centre, long-leg films were obtained after the administration of 150 ml of contrast material. The percentage venograms adjudicated as inadequate by at least one radiologist and inter-observer disagreement for both series were used as the main study outcome measures. Prior to the study, both radiologists agreed on the standardized criteria for a normal, abnormal and inadequate test result using a separate set of films.An inadequacy rate of 20% was found for the Rabinov-Paulin venography series (n = 123), whereas only 2% of the L26long-leg films were inadequate for interpretation (p <0.001). The interobserver disagreement for inadequacy, presence or absence of deep-vein thrombosis was 2I% for the Rabinov and Paulin venograms and 4o/" for the long-leg films (kappa, 0.65 and 0.92; 95% confidence intervals: 0.53 to 0.77 and 0.84 to 0.99, respectively; p <0.002).We conclude that the long-leg method is superior to the Rabinov-Paulin method in the venographic diagnosis of deep-vein thrombosis in symptomatic outpatients since noninterpretable test results are rarely observed and it reduces both unnecessary treatment of patients without deep-vein thrombosis and limits the undertreatment of patients with the disease.

Diagnosis of DVT

“…41 Even when venography is performed by experienced radiologists, inadequate imaging is common; in up to 20% of venograms there is inadequate visualization of a venous segment. 13,[42][43][44][45][46] Further, venography can be diffi cult to interpret and the designation of "DVT present" or "DVT absent" is subject to a considerable degree of both intraobserver ( k values ranging from 0.56-0.95) and interobserver ( k values ranging from 0.47-0.92) variation. 43 53 of patients).…”

Diagnosis of deep vein thrombosis, an overview

“…It was by the use of this technique that the errors of the clini cal examination were recognized. Currently it is still regarded as the gold standard for the assess ment of the diagnosis of DVT [30]. If adequately performed, CV outlines the entire deep venous system of the leg, including the common iliac vein and inferior caval vein.…”

“…The second limitation of CV is related to the sometimes difficult technique and interobserver disagreement in interpretation of the venograms [30,39,40], Lensing et a l compared the Rabinov technique [21] with the long-leg method: the in jection of a larger volume of contrast medium and the concomitant use of long films instead of spot films. They concluded that the long-leg method is superior, since it significantly improved interobserver agreement (from 79 to 96%) and increased the number of interpretable venograms (from 80 to 98%) [30].…”

“…They concluded that the long-leg method is superior, since it significantly improved interobserver agreement (from 79 to 96%) and increased the number of interpretable venograms (from 80 to 98%) [30].…”

Post-operative deepvein thrombosis is infrequent in Alaska Natives

“…Meta-analysis of level 1 studies evaluating this issue estimates a sensitivity of 62% (7). If a sensitivity of 62% and an expected rate of DVT of 30-60 % (10,(12)(13)(14) are assumed, the number of DVTs anticipated in this study would be 12 to 24. The study group may also be subject to a selection bias.…”