TABLE 1

Computed tomography (CT) with and without contrast: indications and protocols

Intravenous contrast required
Malignancy workup and follow-up may require contrast to delineate hila, chest wall, vascular margins, or recurrent or residual tumor
CT pulmonary angiography for pulmonary embolism
CT pulmonary venography for superior vena cava syndrome
CT pulmonary angiography for arteriovenous malformation Suspected or known malignancy or infection of chest wall or mediastinum
Intravenous contrast usually not required
Solitary pulmonary nodule a
Lung screening with low-dose CT
Pulmonary parenchyma, to evaluate for infection, inflammation, edema
Interstitial lung diseaseb
Pleural effusionc
Airway assessment

  • ↵a However, contrast enhancement may help identify tumors such as carcinoid and may better highlight internal morphology. Dynamic enhancement is also occasionally performed.

  • ↵b Tailored protocol uses thinner slices and expiratory images to evaluate for air-trapping and dynamic airway compromise.

  • ↵c Contrast is required to evaluate for empyema and suspected or known pleural malignancy.