Contrast-enhanced US in the assessment of the ilio-caval axis in deep venous thrombosis

To assess the feasibility and the accuracy of a new technique in the evaluation of deep venous thrombosis (DVT) in the ilio-caval axis.

Thirty-eight patients with suspected DVT were prospectively examined with unenhanced and enhanced colour-Doppler ultrasonography, and ascending contrast venography. Thirty-five out of 38 patients underwent US phlebography, consisting in manual injection of Levovist (Schering Ag, Berlin, Germany) through a 21-G cannula in a suitable dorsal vein of the foot ipsilateral to the suspected DVT. Three patients in whom it was not possible to cannulate a dorsal vein of foot underwent contrast-enhanced US after injection of Levovist through an antecubital vein, but where excluded from the present study. A contrast venogram was nonetheless carried out in all out three patients for comparison with the US-phlebography findings.

US-phlebography allowed better definition of the presence and extension of deep vein thrombosis in all patients, when compared to conventional color-Doppler US. In the evaluation of suspected acute thrombosis, the comparative efficacy of Doppler-US and US phlebography compared with ascending phlebography as the gold standard, was as follows: sensitivity of 85.7% and 90%, specificity of 71.4 and 100%, accuracy of 80.9 and 95.2%, PPV of 85.7, and 100%, and NPV of 71.4, and 75%, respectively. In the assessment of chronic thrombosis, US and US phlebography achieved a sensitivity of 90% and 100%, a specificity of 75% and 100%, an accuracy of 85.7% and 100%, a PPV of 100, 100%, a NPV of 87.5, 100%, respectively. No complications related to US phlebography were observed.

US-phlebography is a promising tool in the assessment of deep vein thrombosis, being highly accurate and feasible. However, further studies based on larger series are mandatory to confirm our promising results and establish a standardised role for this new technique.