To evaluate right iliac vein and left iliac vein compression in asymptomatic subjects, right-sided and left-sided iliofemoral deep vein thrombosis patients.

A retrospective analysis of records and computed tomography images was conducted in 200 asymptomatic subjects (male:female, 100:100). A prospective analysis was conducted in 79 consecutive deep vein thrombosis patients (left:right deep vein thrombosis, 47:32) who had undergone contrast-enhanced computed tomography examination. The minor diameter and percentage compression of the iliac vein were evaluated.

In asymptomatic subjects, 13.5% had right iliac vein compression >50%, 2.0% had right iliac vein compression >70%, mean compression was 23.48%; 45.0% had left iliac vein compression >50% and 17.0% had left iliac vein compression >70%, mean compression was 47.58%. Right iliac vein sandwiched between the right external iliac artery and the right internal iliac artery was the most common compression pattern (59.26%). Males had higher right iliac vein compression than the females (male:female, 26.29%:20.68%, P < 0.001). Mean percentage compression of the right iliac vein was higher in right deep vein thrombosis patients than in left deep vein thrombosis patients (right:left deep vein thrombosis, 48.54%:22.29%, P < 0.001).

Similar to left iliac vein compression, right iliac vein compression was a frequent imaging finding in CT and represented a normal anatomic pattern. Right deep vein thrombosis patients had more serious right iliac vein compression than left deep vein thrombosis patients, and further research is required on the association of right iliac vein compression with right iliofemoral deep vein thrombosis.