Iliac vein obstruction: accuracy of Direct Multidetector Computed Tomographic Venography and duplex ultrasound.

Objectives: To evaluate the accuracy of direct computed tomographic venography (DCTV) and duplex ultrasound (DUS) in the identification of iliac vein obstruction in highly symptomatic patients with severe chronic venous disease (CVD) compared with intravascular ultrasound (IVUS).

Methods: this study involved patients who had advanced CVD (CEAP C3-6). All patients underwent DCTV, venous duplex scanning, and IVUS. The presence of iliac vein obstruction was detected, and degree of obstruction was classified into 3 grades (grade I, 0% to 49%; grade II, 50% to 79%; and grade III, 80% or greater). The sensitivity, specificity, PPV, NPV, and accuracy were calculated for each modality compared with IVUS. Inter-observer agreement was assessed using the κ coefficient.

Results: of 94 patients with CVD, IVUS identified iliac vein obstruction in 55 (58.5%) patients (25.5% was grade 1, 27.3% was grade 2, 47.3% was grade 3). The sensitivity, specificity of DCTV in diagnosing obstruction was (96%, 95% in grade 1; 100%, 100% grade 2; 100%, 100% in grade 3, respectively). The sensitivity, specificity of DUS was (63.9%, 65% in grade 1; 68%, 82% in grade 2, and 70%, 85% in grade 3, respectively). The overall agreement of DUS was 0.73 (95% CI, 0.70-0.79), and DCTV was 0.96 (95% CI, 0.91- 0.97).

Conclusions: DUS is a reasonable initial imaging modality for the identification of significant iliac vein obstruction. DCTV provides an accurate reproducible imaging for accurate estimation needed for treatment planning.

Advances in knowledge: Direct CT Venography provides accurate reproducible radiological information required for treatment planning of patients with Iliac vein obstruction including accurate assessment of site of obstruction, its morphology, and degree of obstruction and it can replace the use of indirect CT venography using smaller amount of contrast media with accurate diagnosis.