Compression of the left common iliac vein between the right common iliac artery and the spine — reported as percentage narrowing with collaterals, in a patient with left leg swelling or left iliofemoral DVT.
Orient first
- Some compression is common in asymptomatic people; it matters with symptoms, DVT or collaterals.
- Left-sided iliofemoral DVT in a young woman is the typical presentation.
- Stenting is the treatment; intravascular ultrasound is the procedural reference.
Acquire the study
- CT venography (delayed venous phase, around 120–180 s) of the abdomen and pelvis with axial and sagittal reformats.
The manoeuvre
- Left common iliac vein at the crossing of the right common iliac artery: minimal diameter in mm vs the distal vein — percentage narrowing.
- Pelvic and lumbar collaterals crossing to the right on coronal reformats; ascending lumbar vein calibre in mm.
- Thrombus as a filling defect in the venous phase from the iliac to the femoral veins.
What confirms it
- Left common iliac vein compression with collaterals or thrombus in a symptomatic patient.
What licenses you to exclude it
- No narrowing and normal phasic femoral flow on both sides make significant compression unlikely.
The classic misread
- Reporting asymptomatic anatomical compression as disease.
- Missing it in a left DVT because only the femoral veins were scanned.