What Can a Sinus CT Show When Sinus Infections Keep Returning?

What Can a Sinus CT Show?

When sinus symptoms repeatedly return, a CT may show:

• Thickened or inflamed sinus tissue
• Fluid or opacification inside a sinus
• Narrowed or obstructed drainage pathways
• Nasal polyps or another soft-tissue finding
• A deviated septum or other anatomical variation
• A pattern suggesting dental-related sinus inflammation
• An uncommon abnormality requiring further evaluation

A CT cannot determine from imaging alone whether every episode was a bacterial infection. Its findings must be interpreted alongside the patient’s symptoms, medical history, examination, and the timing of the scan.

Are the Infections Recurrent—or Are the Symptoms Chronic?

This distinction is important because recurring acute rhinosinusitis and chronic rhinosinusitis describe different patterns.

Recurrent acute rhinosinusitis

Recurrent acute rhinosinusitis generally refers to four or more separate episodes within one year, with symptoms resolving between episodes.

Someone with this pattern may feel relatively normal between infections. An evaluation may focus on whether allergies, impaired drainage, anatomy, or another factor is making acute episodes more likely.

Chronic rhinosinusitis

Chronic rhinosinusitis involves symptoms that persist for at least 12 weeks. Patients may have ongoing nasal obstruction or drainage, with possible facial pressure and reduced smell.

A chronic rhinosinusitis diagnosis requires objective evidence of inflammation, which may be identified through nasal endoscopy, CT imaging, or another appropriate examination.

If symptoms never fully clear, the condition may be chronic rather than a series of separate infections.

What Is a Sinus CT?

A sinus CT scan is an imaging examination that uses specialized X-ray equipment and computer processing to produce cross-sectional images of the nose and paranasal sinuses.

The images can be reviewed in multiple planes, allowing a provider to evaluate:

• The individual sinus cavities
• Sinus drainage pathways
• The nasal septum
• The turbinates
• Surrounding bony anatomy
• Areas of fluid or thickened tissue
• Certain soft-tissue abnormalities

Routine sinus CT scans are commonly performed without contrast. Contrast, MRI, or another examination may be recommended when more information is needed about a complication, mass, blood vessel, or surrounding soft tissue.

The imaging process is generally brief and noninvasive, but the exact procedure and total appointment time depend on the equipment and facility.

What Might a CT Show When Symptoms Keep Returning?

Several CT findings may help explain why a patient repeatedly develops sinus symptoms.

Persistent sinus inflammation

CT imaging may show thickening of the sinus lining, fluid, or partial or complete opacification of a sinus cavity.

These findings may support a diagnosis involving sinus inflammation when they correspond with symptoms such as nasal obstruction, drainage, facial pressure, or reduced smell.

An abnormal scan does not automatically mean that an active bacterial infection is present. CT cannot always determine whether inflammation is viral, bacterial, fungal, dental, allergic, or related to another cause.

Narrowed sinus drainage pathways

Each sinus drains through a relatively small opening. Inflammation, anatomy, polyps, or another condition may narrow these pathways and interfere with ventilation or mucus drainage.

CT imaging can map drainage anatomy that cannot be completely seen during a routine examination. This information may help determine whether a recurring pattern involves the same sinus or drainage region.

The ostiomeatal complex is not a single canal. It is an anatomical drainage region used by the frontal, maxillary, and anterior ethmoid sinuses. A CT may show inflammation or narrowing in this area.

Nasal polyps or another soft-tissue finding

Nasal polyps are noncancerous growths associated with inflammation of the nasal and sinus lining. They may contribute to congestion, reduced smell, postnasal drip, and impaired sinus drainage.

A CT may show soft-tissue changes consistent with polyps and help determine how extensively the sinuses are involved. However, CT imaging cannot always distinguish a routine inflammatory polyp from every other soft-tissue abnormality.

A finding that is unusual or limited to one side may require nasal endoscopy, MRI, biopsy, or another evaluation.

A deviated septum

A deviated septum occurs when the wall of cartilage and bone separating the nasal passages bends toward one side.

A CT can show the position of the septum and its relationship to the surrounding anatomy. A deviation may contribute to nasal obstruction, but it does not automatically cause recurring infections.

Many people have some degree of septal deviation without significant symptoms. The provider must determine whether the finding corresponds with the patient’s symptoms and drainage pattern.

Enlarged turbinates

Turbinates are structures along the sidewalls of the nose that warm, humidify, and filter inhaled air. Their soft tissue can swell in response to allergies, irritants, infection, or other inflammation.

A CT may show enlarged turbinates or reduced space within a nasal passage. Because turbinate swelling changes over time, an office examination or nasal endoscopy is also important.

Enlarged turbinates commonly affect nasal airflow but do not, by themselves, prove why infections or sinus symptoms keep returning.

Dental-related sinus inflammation

The roots of the upper teeth are located close to the maxillary sinuses. A dental infection, extraction, implant, or another dental condition may sometimes contribute to inflammation in a nearby sinus.

A CT may show a pattern that raises concern for a dental source, particularly when changes are concentrated in one maxillary sinus. It does not replace a dental examination or dedicated dental imaging.

Fungal material

Some fungal sinus conditions can affect an individual sinus and produce recognizable patterns on CT imaging. The scan may raise suspicion for fungal material, but clinical evaluation and sometimes a procedure are needed to establish the diagnosis.

An uncommon growth or mass

Most recurring sinus symptoms are not caused by a tumor. However, CT imaging may occasionally reveal an abnormal soft-tissue area, expansion of a sinus, or changes involving nearby bone.

Additional imaging or biopsy may be required to determine what the abnormality represents. Persistent one-sided obstruction, bleeding, facial numbness, or vision changes deserves careful evaluation.

Does Every Recurring Sinus Infection Require a CT?

No. Imaging is generally not recommended for an uncomplicated episode of acute rhinosinusitis.

According to the American College of Radiology’s patient-facing appropriateness guidance, imaging is not typically recommended for acute rhinosinusitis alone. CT may be considered when symptoms are chronic or recurrent, a complication is suspected, the diagnosis remains uncertain, or detailed anatomy is needed for treatment planning.

A provider may consider CT imaging when:

• Symptoms persist for at least 12 weeks
• Distinct sinus episodes repeatedly return
• Appropriate treatment has not produced the expected improvement
• Nasal endoscopy shows an abnormality
• One side is consistently affected
• Bloody drainage or another concerning symptom is present
• A procedure is being considered

CT imaging uses ionizing radiation, so it should be ordered when its expected diagnostic value outweighs the potential risk.

Why Does the Timing of the CT Matter?

A scan performed during a cold or an acute respiratory illness may show temporary inflammation. Those changes may resolve and may not explain why symptoms repeatedly return.

When evaluating recurrent episodes, a provider may choose the timing of the scan based on the clinical question. Imaging during symptoms may document an active pattern, while imaging between episodes may provide information about persistent inflammation or underlying anatomy.

There is no single correct timing for every patient. The provider can determine when the scan is most likely to answer the relevant diagnostic question.

What Happens After the CT?

Treatment depends on the entire evaluation rather than the scan alone.

If allergies are contributing, allergy testing and treatment may be considered. Chronic inflammation may be managed with an appropriate nasal spray, saline treatment, or another medical option.

Nasal irrigation should be performed only with distilled, sterile, or previously boiled and cooled water. The device should be cleaned and dried after use.

If a structural problem or persistent sinus disease significantly affects drainage, a provider may discuss additional options. A CT abnormality does not automatically mean that a procedure is necessary. Treatment recommendations should reflect the symptoms, examination, previous care, imaging findings, and individual health factors.

Results and recovery experiences vary.

When Should Recurring Sinus Symptoms Be Evaluated?

Consider scheduling an evaluation when:

• Four or more distinct sinus episodes occur within a year
• Symptoms last at least 12 weeks
• Congestion or drainage never fully clears
• Facial pressure repeatedly affects the same area
• The sense of smell decreases
• Symptoms return despite appropriate care
• One side is consistently affected
• Nasal drainage is bloody, foul-smelling, or persistently one-sided
• Symptoms interfere with sleep, work, or daily activities

Seek prompt medical attention for swelling or redness around the eyes, vision changes, facial numbness or weakness, severe headache, confusion, neck stiffness, significant facial swelling, high fever with worsening symptoms, or other rapidly progressing symptoms.

Understand Why Sinus Symptoms Keep Returning

A sinus CT may help identify chronic inflammation, narrowed drainage pathways, polyps, anatomical variations, dental-related disease, or another finding that could contribute to recurring symptoms. It cannot, by itself, confirm that every episode was a bacterial infection or establish that every abnormality is responsible.

Buckeye Breathe Free provides sinus and ENT evaluations for patients in Akron, Cuyahoga Falls, Fairlawn, and surrounding Northeast Ohio communities. Schedule an appointment to discuss recurring sinus symptoms and determine whether nasal endoscopy, CT imaging, allergy testing, or another approach may be appropriate.