Incidental lung & mediastinal findings

What to systematically look for outside the heart on every cardiac CT — nodules, cystic spaces (with vs without the central dot), pulmonary edema, and mediastinitis.

When evaluating a cardiac CT, reading physicians must systematically review the lung fields and mediastinum for incidental pathologies. These are the high-yield categories you should be looking for on every read.

1
Pulmonary nodules

The sensitivity of detecting small, scattered pulmonary nodules can be substantially improved by using Maximum Intensity Projections (MIP) during post-processing.

See Reconstruction views for the broader MPR / MIP / VR primer.

2
Cystic lung spaces — the central dot sign

If cystic air spaces are identified in the lungs, internal morphology offers a diagnostic clue:

  • Cysts with a central “dot” → characteristic of emphysema (the dot is the centrilobular vessel)
  • Cysts lacking a central dot → more indicative of collagen vascular diseases, lymphoma, or HIV
3
Pulmonary edema / heart failure

Frequently seen incidentally on cardiac CTs. Left ventricular failure manifests in the lungs as:

  • Diffuse ground-glass opacities
  • Smooth interlobular septal thickening (Kerley B lines)
  • Peribronchial cuffing
  • Bilateral pleural effusions
4
Mediastinitis

Inflammatory or infectious conditions in the mediastinum present as distinct thickening and increased attenuation of the mediastinal fat. High clinical mortality — flag it.

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Pulmonary embolism on cardiac CT
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Cardiac chambers & wall motion