What it is (overview)

A CT Sinuses without IV Contrast (also called a CT scan of the sinuses or CT of the nasal cavity) is a diagnostic imaging test that uses X-rays and computer processing to create detailed, cross-sectional pictures of your sinus cavities and nearby structures, including the nasal passages. “Without IV contrast” means no contrast dye is injected into a vein—this exam focuses on the natural differences between air, bone, and soft tissue to show sinus anatomy clearly.

This scan helps your clinician see whether your sinuses are open and draining normally or blocked by swelling, mucus, polyps, or structural issues. It can also show thickened sinus lining, fluid levels, and bony changes. Results are interpreted by a radiologist and reported to your ordering provider (often an ENT evaluation).

In plain language, results may mean:

Normal/clear sinuses: Air-filled sinuses with open drainage pathways and no significant inflammation.

Signs of sinusitis (sinus infection/inflammation): Swollen lining, mucus or fluid in a sinus, or blocked openings. This may support treatment decisions (medications vs. further evaluation).

Obstruction or anatomic variant: A deviated nasal septum, narrowed drainage channels, enlarged turbinates, or other structural differences that may contribute to chronic sinus problems, congestion, headaches, or facial pain.

Other findings: The scan may show nasal polyps, dental-related sinus changes, or (less commonly) masses or bony abnormalities that need additional follow-up testing.

When & why it's usually done

Healthcare providers most often order a CT scan of the sinuses when symptoms suggest ongoing or complicated sinus disease, when symptoms are not improving with treatment, or when planning procedures. Because CT images bone and air spaces extremely well, it is especially helpful for mapping sinus anatomy and locating areas of blockage.

This test is commonly ordered if you have:

Persistent or recurrent sinus symptoms such as nasal congestion, thick drainage, post-nasal drip, reduced sense of smell, or pressure/fullness lasting weeks or coming back frequently (possible chronic sinusitis).

Facial pain, pressure, or headaches that may be related to sinus inflammation or blocked drainage pathways—especially when symptoms keep returning or don’t match a simple cold.

Concern for sinus infection complications (for example, severe symptoms, fever with significant facial swelling, or symptoms that worsen despite treatment). While CT can help evaluate severity and anatomy, your clinician will decide if other imaging is needed based on your situation.

Nasal obstruction or breathing difficulty possibly due to a deviated septum, enlarged turbinates, polyps, or other structural problems in the nasal cavity.

Pre-surgical planning before endoscopic sinus surgery or to guide ENT treatment decisions. CT helps the ENT specialist understand your individual sinus anatomy and the extent of disease.

Follow-up of known chronic sinus disease to assess response to treatment or to evaluate ongoing symptoms.

Common diseases related to it

• Acute sinusitis (sinus infection)
• Chronic sinusitis (chronic rhinosinusitis)
• Recurrent sinus infections
• Nasal polyps
• Deviated nasal septum
• Turbinate hypertrophy (enlarged turbinates)
• Sinus ostial obstruction (blocked sinus drainage pathways)
• Allergic rhinitis with secondary sinus inflammation
• Fungal sinusitis (in select cases)
• Odontogenic sinusitis (sinus inflammation related to dental infection)
• Mucocele (mucus-filled sinus cyst)

Health goals where it may help

• Identifying the cause of chronic nasal congestion, sinus pressure, headaches, or facial pain
• Confirming or ruling out sinusitis when symptoms persist despite treatment
• Guiding an ENT evaluation by clarifying sinus and nasal cavity anatomy
• Planning targeted treatment (medical therapy, allergy management, or possible sinus surgery)
• Reducing repeat infections by finding structural contributors to poor sinus drainage
• Monitoring chronic sinus problems to support long-term symptom control and quality of life