Evaluation of the diagnostic accuracy of contrast enhanced ultrasonography in chronic iliac venous obstruction.

OBJECTIVE

The noninvasive diagnosis of chronic iliac vein obstruction can be challenging. Noninvasive modalities are available, but each has its own merits and drawbacks. Intravascular ultrasound (IVUS) is considered the diagnostic reference standard, but it is invasive. The role of contrast-enhanced ultrasonography in chronic iliac vein obstruction has so far not been studied.

METHODS

This is a single-center retrospective study. Thirty-nine patients, suspected to have chronic iliac venous obstruction, underwent unenhanced ultrasonography, contrast-enhanced ultrasonography with Lumason, and IVUS on the same day.

RESULTS

Most of the data set was female, had post thrombotic lesions, and belonged to CEAP Class C4 or higher. The intraclass correlation coefficient (kappa, average measures) between enhanced and unenhanced ultrasonography was 0.9 (95% confidence interval [CI], 0.87-0.92), indicative of very good agreement. However, the correlation coefficients between enhanced ultrasonography and IVUS and unenhanced ultrasonography and IVUS were 0.6 (95% CI, 0.16-0.67) and 0.5 (95% CI, 0.37-0.75), respectively, indicative of less optimal agreement. Considering IVUS as the reference standard, diagnostic accuracies for ultrasonography for external iliac vein with and without Lumason use were 71.3% and 71.4%, respectively. Diagnostic accuracies for ultrasonography for common iliac vein with and without Lumason use were 53.2% and 56.7%, respectively, when compared with IVUS.

CONCLUSIONS

The measures of diagnostic accuracy of contrast-enhanced ultrasonography and unenhanced ultrasonography are similar to each other in the diagnosis of chronic iliac vein obstruction when compared with a reference standard such as IVUS. Further studies are needed to delineate the complimentary value of contrast-enhanced ultrasonography in the diagnosis of chronic iliac vein obstruction.