MRI PNS (Paranasal Sinuses), MRI Protocol for PNS:, Advantages of MRI PNS:, Sequences commonly used:

 MRI PNS (Paranasal Sinuses)

MRI of the Paranasal Sinuses (PNS) is a non-invasive imaging technique that provides detailed information about the soft tissues, mucosa, sinus cavities, and adjacent structures. Unlike CT, which is excellent for bony anatomy, MRI is particularly useful for evaluating soft tissue pathology and complications.

📌 Indications:

1. Chronic Sinusitis – when medical or surgical treatment is being considered.

2. Sinonasal Polyps – differentiation from retained secretions.

3. Fungal Sinusitis – invasive vs. non-invasive.

4. Tumors of paranasal sinuses and nasal cavity.

5. Perineural Spread of malignancy.

6. Orbital or Intracranial Complications of sinus disease.

7. Cerebrospinal Fluid (CSF) Leak – evaluation of meningoencephalocele.

📌 MRI Protocol for PNS:

• Planes: Axial, Coronal, Sagittal.

• Sequences commonly used:

  • T1-weighted – anatomy and tumor characterization.

  • T2-weighted – fluid, inflammation, edema.

  • STIR / Fat-suppressed T2 – to identify mucosal thickening, polyps, edema.

  • Post-contrast T1 with fat suppression – for tumor, abscess, complications.

  • Diffusion-weighted imaging (DWI) – for abscess, cholesteatoma-like lesions.

📌 Advantages of MRI PNS:

• Excellent soft tissue contrast (tumor vs. inflammation vs. secretions).

• Useful in orbital and intracranial extension assessment.

• Detects perineural spread of malignancy.

• Differentiates mucocele vs. tumor.

📌 Limitations:

• Poor visualization of bony anatomy (CT is superior for bone and surgical planning).

• Motion artifacts (especially in uncooperative patients).

• Less sensitive for small osteomeatal complex obstruction.