Computed tomography venography versus intravascular ultrasound in the diagnosis of iliofemoral vein stenosis.

: Iliofemoral vein stenosis can cause debilitating chronic venous disease. Diagnostic tools include both computed tomography venography (CTV) and intravascular ultrasonography (IVUS). We aim to compare the diagnostic performance of CTV and IVUS. : We performed a retrospective study of patients with chronic venous disease presenting with iliac vein compression or post-thrombotic limb symptoms, excluding those with acute deep vein thrombosis, high anaesthesia risk, or who had contrast allergy. All patients received CTV before IVUS, as part of the diagnostic work-up and intervention. The cross-sectional area (CSA) of iliofemoral vein segments obtained from both studies were compared against reference CSAs to derive percentage stenosis. A 50% reduction in CSA was considered significant. : We studied 50 patients between May 2018 and April 2019. 58% of patients had severe disease CEAP C5-6. 48% of patients had at least one vein segment with significant stenosis. The left proximal common iliac vein was the most commonly stenosed vein segment (n = 12, 24% on IVUS). CSA measurements from CTV were greater than those of IVUS, with a correlation coefficient of 0.57 (p < 0.005). Conversely, percentage stenosis measured on CTV was lower than on IVUS, with approximately one-third of significant stenosis missed on CTV (58 veins from CTV vs. 78 from IVUS, p < 0.005). With IVUS as the gold standard, CTV has low sensitivity (37.2%, 95% CI 26.5-48.9) and high specificity (92.5%, 95% CI 89.3-94.9) in detecting significant stenosis. : CTV has limited diagnostic performance in identifying iliofemoral vein stenosis. Patients with normal CTV findings should proceed with IVUS imaging if the clinical features are supportive of iliofemoral vein stenosis.