← All patterns
Widened mediastinum
ChestRadiograph / CT
Mediastinal widening on a chest radiograph (>8 cm on supine AP). The urgent task is to exclude acute aortic injury while considering technical and mass causes.
Differential
Technical (AP / supine / rotation)
common- •Magnification from supine AP projection or poor inspiration
- •Normal on erect PA repeat
Tortuous / unfolded aorta
common- •Elderly, hypertensive; smooth aortic contour
- •Calcified aortic knuckle
Mediastinal haematoma (traumatic aortic injury)
less-common- •Deceleration trauma; loss of aortic contour, left apical cap
- •Contour irregularity/pseudoaneurysm at the isthmus on CT
Lymphadenopathy
less-common- •Lobulated widening; lymphoma, sarcoid or metastatic nodes
- •Systemic symptoms
Mediastinal mass
less-common- •Compartment-specific soft-tissue mass (e.g. thymoma, retrosternal goitre)
- •Displacement of adjacent structures
Thoracic aortic aneurysm
rare- •Focal aortic dilatation with mural calcification/thrombus
- •Smooth contour continuous with the aorta
Key discriminators
- •Projection and technique (repeat erect PA)
- •Aortic contour integrity (trauma) and calcification
- •Trauma history / mechanism
- •Lobulated (nodal/mass) vs smooth vascular contour
- •Displacement of trachea and mediastinal lines
Work-up / next steps
- 1.Repeat erect PA radiograph if technical cause suspected
- 2.CT angiography urgently when aortic injury/dissection possible
- 3.Characterise any mass by compartment on CT
- 4.Correlate with trauma mechanism and haemodynamics
References
- Radiopaedia: Widened mediastinum.
- Wintermark M et al. Imaging of acute aortic injury. RadioGraphics.
Educational clinical decision support only. This differential does not make a diagnosis, is not a medical device, and must never substitute for interpretation by a qualified radiologist correlated with the full clinical picture and prior imaging.