Sinus CT

1. See Also
   1. Sinusitis
   2. Sinus XRay
2. Epidemiology
   1. High False Positive Rate
      1. Upper Respiratory Infection: 85% with CT changes
      2. Asymptomatic adults: 40% with CT changes
   2. References
      1. Gwaltney (1994) N Engl J Med 330:25-30 [PubMed]
      2. Havas (1988) Arch Otolaryngol Head Neck Surg 114:856 [PubMed]
3. Advantages
   1. Much more sensitive than Sinus XRay
   2. Good Sinus Anatomy definition
      1. Views sphenoid and Ethmoid Sinuses well
      2. Defines osteomeatal complex well
4. Indications
   1. Sinusitis refractory to maximal medical management
      1. Recurrent Acute Sinusitis
      2. Persistent Chronic Sinusitis Symptoms
      3. Suspected Osteomeatal complex Occlusion
      4. Suspected Allergic Fungal Sinusitis
   2. Confusing presentation
   3. Evaluation before endoscopic surgery
5. Technique
   1. Full Coronal non-contrast Sinus CT
      1. Standard view indicated in most cases
   2. Limited Sinus CT
      1. Consider as alternative to full Sinus CT
      2. Four non-contiguous 5 mm slices in coronal plane
         1. Frontal Sinus
         2. Anterior ethmoid and Maxillary Sinuses
         3. Posterior ethmoid and Maxillary Sinuses
         4. Sphenoid Sinus
      3. Advantages
         1. Less expensive
         2. Less radiation
      4. Disadvantage
         1. Unknown efficacy
   3. Contrast Sinus CT
      1. Indicated in Periorbital Cellulitis or abscess
6. Timing of scan
   1. Perform during maximal medical therapy
   2. Delay if URI present
7. Relative Contraindications
   1. Submaximal medical Management
   2. Upper Respiratory Infection
   3. Acute sinus infection
8. Interpretation
   1. Findings consistent with Rhinosinusitis
      1. Air-fluid levels
      2. Total opacification
      3. Mucosal thickening >5 mm
   2. Complications identified by Sinus CT
      1. Osteomeatal Complex Obstruction
      2. Allergic Fungal Sinusitis
9. References
   1. Mukherji (1998) Radiology 207:417-22 [PubMed]
   2. Okuyemi (2002) Am Fam Physician 66:1882-6 [PubMed]