For chronic sinusitis, is a non-contrast or contrast-enhanced computed tomography (CT) facial scan preferred?

CT Imaging for Chronic Sinusitis: Non-Contrast is Preferred

For chronic sinusitis, CT imaging of the facial sinuses should be performed without contrast, as contrast-enhanced CT is not necessary to demonstrate findings of chronic rhinosinusitis or for surgical planning of paranasal sinus inflammatory disease. 1

Rationale for Non-Contrast CT in Chronic Sinusitis

Benefits of Non-Contrast CT

• Provides excellent bony detail, which is crucial for:

  • Confirming and evaluating chronic rhinosinusitis (CRS)
  • Identifying anatomic variants for presurgical planning
  • Visualizing mucosal thickening, sinus opacification, polyps, retention cysts, and sclerosis/thickening of sinus walls 1
  • Evaluating the extent of disease and identifying anatomic variants that narrow sinus drainage pathways 1

• Critical for surgical planning by identifying:

  • Anatomic variants that increase risk for intracranial, intraorbital, and vascular injury
  • Potential sites for CSF leak 1

When is Contrast Indicated?

Contrast-enhanced CT is generally NOT indicated for routine chronic sinusitis evaluation but may be appropriate in specific scenarios:

• Suspected invasive fungal sinusitis (particularly in immunocompromised patients) 1
• Suspected sinonasal mass requiring differentiation from inflammatory disease 1
• Cases with suspected orbital or intracranial complications 1
• When MRI cannot be performed but soft tissue detail is needed 1

Imaging Protocol Considerations

• Multiplanar CT imaging is recommended:

  • Thin-slice axial images with reformations in coronal and sagittal planes
  • Or direct coronal images as clinically warranted 1
  • Sinus CT protocol that can be used by image guidance systems if surgery is planned 1

• Low-dose techniques may be limited in visualizing surgically relevant anatomical structures in patients with:

  • CRS with nasal polyps
  • History of sinus surgery 1

Important Clinical Considerations

• Asymptomatic sinusitis found incidentally on CT scans should not be treated, as it represents a normal variant 2
• CT findings should always be interpreted in conjunction with clinical and endoscopic findings to avoid overdiagnosis 2, 3
• Up to 40% of asymptomatic adults may have abnormalities on sinus CT scans 2
• Dual-phase imaging (without and with contrast) is not necessary for chronic sinusitis 1

Special Situations

• For suspected sinonasal mass: Both non-contrast CT (for bone detail) and contrast-enhanced MRI (for soft tissue detail) may be needed 1
• For invasive fungal sinusitis: MRI with contrast provides more accurate evaluation of complex sinus secretions and extension of disease into adjacent soft tissues 1
• For silent sinus syndrome: CT is superior to MRI in demonstrating osseous thinning, obstruction of the infundibulum, and lateralization of the uncinate process 1

In conclusion, non-contrast CT is the imaging modality of choice for chronic sinusitis, providing the necessary anatomical detail for diagnosis and surgical planning while avoiding unnecessary radiation exposure and contrast administration.