What Is an ENT Looking for on a Sinus CT Scan?

Dr. Madeleine Samuelson Herman, MD, MPH, FAAOA

If you’ve ever had a sinus CT scan, you may have wondered what your ENT is actually looking at—and how those black-and-white images explain your symptoms.

A sinus CT is one of the most valuable tools we use to diagnose chronic sinus problems, nasal obstruction, and recurrent sinus infections. Unlike a regular exam, it allows us to see deep inside the sinus cavities and nasal passages to understand why you’re not breathing well. Here’s what an ENT is evaluating when we review your sinus CT scan.

1. Sinus Drainage Pathways (The Most Important Part)

Healthy sinuses constantly produce mucus that drains through tiny openings into the nose.On a sinus CT, we carefully examine whether these drainage pathways are:

• Open and functioning normally

• Narrowed or blocked

• Completely obstructed by inflammation, polyps, or anatomy

Blocked drainage is one of the most common causes of chronic sinus infections, facial pressure, and postnasal drip.

2. Mucosal Thickening & Inflammation

Sinus cavities should normally be filled with air.On CT imaging, inflammation shows up as thickened lining or gray areas inside the sinuses.

An ENT looks for:

• Mild vs. severe inflammation

• Which sinuses are involved (maxillary, ethmoid, frontal, sphenoid)

• Patterns that suggest chronic sinusitis versus acute infection

This helps determine whether symptoms are better treated with medication—or whether procedures like balloon sinuplasty or sinus surgery should be considered.

3. Nasal Polyps

Nasal polyps are soft, inflammatory growths that can block airflow and sinus drainage.

On a sinus CT scan, polyps appear as:

• Soft tissue filling the nasal cavity or sinuses

• Areas where air should normally be present

Identifying polyps is essential because they often require long-term medical therapy, steroid treatment, or surgery—and are sometimes associated with asthma or allergies.

4. Septal Deviation & Structural Anatomy

Your nasal septum is the wall between the two sides of your nose.ENTs evaluate whether it is:

• Straight

• Deviated (bent)

• Contributing to nasal blockage or sinus drainage problems

We also look at other anatomical variations—such as enlarged turbinates or narrow sinus openings—that can predispose patients to recurrent sinus infections.

5. Signs of Infection or Trapped Fluid

A sinus CT can show:

• Fluid levels inside the sinuses

• Complete sinus opacification (sinus filled with mucus or infection)

• Chronic changes suggesting long-standing disease

This helps differentiate sinus infections from migraine headaches, allergies, or facial pain from other causes.

6. Surgical Planning (When Needed)

If surgery is being considered, a sinus CT acts as a roadmap.

ENTs use it to:

• Safely navigate sinus anatomy

• Identify delicate structures like the eyes and brain

• Customize surgery to each patient’s anatomy

This precision improves outcomes and safety when performing endoscopic sinus surgery or balloon sinuplasty.

Why In-Office Sinus CT Scans Matter

Many ENT offices now offer in-office sinus CT scans, which provide:

• Quick imaging (usually just a few minutes)

• Lower radiation than traditional CT scans

• Same-day diagnosis and treatment planning

For patients, this means faster answers and fewer delays.

The Bottom Line

A sinus CT scan helps your ENT move beyond symptoms and see what’s really happening inside your sinuses. By evaluating drainage pathways, inflammation, polyps, anatomy, and infection, we can create a treatment plan that’s accurate, personalized, and effective.

If you’re dealing with chronic congestion, facial pressure, or repeated sinus infections, a sinus CT scan may be the key to finally understanding—and treating—the problem.