Imaging for Deviated Septum
CT of the paranasal sinuses without contrast is the recommended imaging study when a patient with deviated nasal septum is being evaluated for surgical correction, but imaging should NOT be performed solely for septal deviation itself 1.
When to Order Imaging
The key distinction is understanding when imaging adds value beyond clinical examination:
Do NOT order imaging if:
- The patient has isolated nasal obstruction from septal deviation visible on anterior rhinoscopy and nasal endoscopy
- No symptoms suggesting chronic rhinosinusitis (CRS) are present
- Physical examination adequately visualizes the entire nasal cavity and septum
CT has limited correlation with physical examination for septal deviation alone and may underestimate obstruction at the internal nasal valve 1. Clinical examination (anterior rhinoscopy and endoscopy) remains the reference standard for evaluating septal deviation 1, 2.
DO order CT paranasal sinuses (without contrast) if:
- Symptoms of chronic rhinosinusitis are present (nasal obstruction, facial congestion/pressure, discolored discharge, hyposmia lasting >12 weeks) 1
- Severe anterior deviation prevents visualization of the middle meatus and posterior nasal cavity on endoscopy 3
- Obstructive middle turbinate hypertrophy is present 3
- Nasal polyps are identified 3
- Recurrent sinusitis or suspected sinus pathology 1
- Surgical planning is needed to identify anatomic variants that increase risk for intracranial, intraorbital, or vascular injury 1
Why CT When Indicated
When imaging is appropriate, CT provides critical information that changes surgical management:
Identifies concomitant pathology not visible on examination: Studies show CT reveals additional sinonasal pathologies in 23.6-84% of patients, including concha bullosa, chronic sinusitis, retention cysts, paradoxical middle turbinate, and antrochoanal polyps 4, 3, 5
Modifies surgical planning: CT findings change the original surgical plan in 8.3-84% of cases, leading to additional procedures beyond simple septoplasty 4, 3, 5
Maps anatomic variants: Critical for identifying structures that increase surgical risk (cribriform plates, lamina papyracea, anterior ethmoidal artery canal) 1
Technical Specifications
- Standard multidetector CT without IV contrast is the modality of choice 1
- Use a sinus CT protocol compatible with image guidance systems if available 1
- Contrast is NOT necessary for inflammatory disease or surgical planning 1
- Cone beam CT (CBCT) is an alternative with lower radiation but limited soft-tissue evaluation 1
Common Pitfalls
Avoid ordering CT reflexively for every septoplasty: The 2022 ACR Appropriateness Criteria explicitly state that CT should not be performed solely for septal deviation evaluation 1. This represents unnecessary radiation exposure and cost when clinical examination is adequate.
Don't rely on CT alone: Physical examination findings often differ significantly from CT findings for septal deviation (p<0.05), and CT doesn't correlate with symptom severity (NOSE scores) 2. Clinical decisions should be based on physical examination and patient complaints, not imaging alone 2.
Recognize when endoscopy is insufficient: If severe anterior deviation blocks your view of posterior structures, or if you identify middle meatal pathology, CT becomes essential rather than optional 3, 6.