Can a computed tomography (CT) scan of the head and brain visualize the sinus cavity?

Visualization of Sinus Cavity on CT Scan of Head and Brain

Yes, a CT scan of the head and brain can visualize the paranasal sinuses, but it typically provides incomplete coverage of the sinus cavity compared to a dedicated CT maxillofacial examination. 1

Limitations of Head CT for Sinus Evaluation

• Standard CT head protocols are not optimized for sinus evaluation and typically provide incomplete coverage of the paranasal sinuses 1
• According to the ACR Appropriateness Criteria, "CT head is not typically performed for the evaluation of CRS (chronic rhinosinusitis) or for presurgical planning of paranasal sinus inflammatory disease" due to this incomplete coverage 1
• When sinus pathology is the primary concern, a dedicated CT maxillofacial examination is preferred over a standard head CT 1

What Can Be Visualized

Despite limitations, a head CT will show:

• Portions of the paranasal sinuses that fall within the field of view
• Maxillary teeth (particularly upper molars and premolars) due to their proximity to the maxillary sinuses 2
• Gross sinus pathology such as significant opacification or air-fluid levels
• Bony structures of the sinuses within the scan field

Comparison with Dedicated Sinus Imaging

For comprehensive sinus evaluation, dedicated imaging is superior:

1. CT Maxillofacial (dedicated sinus CT):

   • Provides excellent bony detail of the entire sinus cavity
   • Shows mucosal thickening, sinus opacification, polyps, and retention cysts 1
   • Identifies anatomic variants that narrow sinus drainage pathways 1
   • Critical for surgical planning 1

2. Cone Beam CT (CBCT) Paranasal Sinuses:

   • Alternative with lower radiation dose than standard CT
   • High accuracy for evaluating odontogenic and nonodontogenic sinusitis 1
   • Limited in evaluation of soft-tissue structures 1, 3

Clinical Implications

• If sinus pathology is suspected as the primary concern, a dedicated CT maxillofacial examination should be ordered rather than a head CT 1
• For suspected intracranial complications of sinusitis, both CT maxillofacial and CT head with contrast may be complementary 1
• For suspected CSF leak involving the sinuses, high-resolution CT of the paranasal sinuses is the first study of choice 1

Common Pitfalls

• Relying on head CT alone for sinus evaluation may miss pathology in areas not included in the field of view
• Mistaking normal anatomic variants for pathology (common in sinus anatomy)
• Not recognizing that soft tissue evaluation is limited on non-contrast head CT
• Failing to order dedicated sinus imaging when sinus pathology is the primary concern

In summary, while a CT scan of the head and brain will show portions of the sinus cavity, a dedicated CT maxillofacial examination is the appropriate choice when comprehensive evaluation of the paranasal sinuses is needed.