A narrowed or occluded SVC with chest wall and mediastinal collaterals; name the cause (tumour, nodes, thrombus around a line) and the extent (brachiocephalic veins, azygos) because stenting depends on it.
Orient first
- Malignancy (lung cancer, lymphoma) causes most; catheter-related thrombosis is the benign leader.
- Collaterals: azygos, internal mammary, lateral thoracic, and a hot spot in the liver (quadrate lobe) on CT.
- Stanford classification describes extent (verify the one in use).
Acquire the study
- CT chest with contrast timed for the SVC (or with injection in both arms), axial and coronal reformats.
The manoeuvre
- SVC: narrowest diameter in mm, length of stenosis or occlusion in cm.
- Brachiocephalic and subclavian veins; azygos arch patency (above or below the obstruction).
- Cause: mass, nodes, fibrosing mediastinitis, thrombus around a catheter.
- Collaterals: chest wall, mediastinal, internal mammary; focal hepatic enhancement in segment IV.
- Airway compression and pericardial effusion.
What confirms it
- Narrowed or occluded SVC with collateral circulation.
What licenses you to exclude it
- A normal-calibre opacified SVC without collaterals excludes obstruction.
The classic misread
- Calling an inflow artefact from unopacified blood a thrombus.
- Missing the azygos level, which changes the haemodynamics and stent planning.