What Can a Sinus CT Show When Nasal Congestion Is Mostly on One Side?

What Can a Sinus CT Show About One-Sided Nasal Congestion?

A sinus CT scan can provide detailed images of the nasal and sinus anatomy, helping identify structural differences, inflammation, and other abnormalities that may be associated with persistent one-sided symptoms.

CT imaging may reveal findings such as:

• A deviated nasal septum
• Enlarged turbinates
• Narrowed or obstructed sinus drainage pathways
• Thickening of the sinus lining
• Fluid accumulation within a sinus
• Soft-tissue abnormalities or unusual growths

However, a sinus CT scan does not always establish the exact cause of nasal congestion or explain whether an imaging finding is responsible for a patient’s symptoms.

Results must be interpreted alongside the patient’s medical history, symptoms, examination findings, and response to previous treatments.

What Is a Sinus CT Scan?

A CT scan, or computed tomography scan, is a diagnostic imaging tool that uses specialized X-ray technology and computer processing to create detailed cross-sectional images of targeted areas of the body.

A sinus CT scan provides detailed images of the nasal passages, paranasal sinuses, sinus drainage pathways, and surrounding bone and tissue structures.

These images may help an ENT specialist:

• Evaluate persistent or recurring sinus symptoms
• Assess structural differences in the nose and sinuses
• Identify narrowed or obstructed sinus drainage pathways
• Look for fluid accumulation or thickening of the sinus lining
• Evaluate the location and extent of suspected sinus inflammation
• Investigate certain concerning findings
• Obtain additional information for treatment or surgical planning

CT imaging is one component of a broader ENT evaluation rather than a replacement for a clinical examination.

What Happens During a Sinus CT Scan?

During a conventional sinus CT scan, the patient typically lies on a padded table that moves through a ring-shaped scanner.

Depending on the equipment used, some in-office sinus CT systems may instead allow the patient to sit or stand during imaging.

The scanner captures multiple images, which are processed to provide detailed views of the sinuses and surrounding structures.

The scanning procedure is generally quick and noninvasive.

Most routine sinus CT scans do not require contrast dye. However, contrast-enhanced imaging or another imaging examination may be recommended when certain complications or abnormalities are suspected.

CT imaging uses ionizing radiation and should be performed when the expected diagnostic benefits justify the exposure.

What Can a Sinus CT Scan Show?

Persistent one-sided nasal congestion can have several possible causes. A sinus CT scan may provide useful information about the following findings.

One-Sided Inflammation

Sinusitis involves inflammation of the lining of one or more paranasal sinuses.

When inflammation primarily affects one side, a sinus CT scan may show:

• Thickening of the sinus lining
• Fluid accumulation within a sinus cavity
• Partial or complete sinus opacification
• Changes involving a sinus drainage pathway

These findings may help identify which sinuses are affected and the extent of the abnormalities.

However, CT imaging alone generally cannot determine whether inflammation is caused by a viral, bacterial, fungal, or dental condition.

An ENT specialist will interpret the images alongside the patient’s symptoms, examination findings, and medical history.

A Deviated Septum

A deviated septum is an anatomical variation in which the nasal septum is displaced away from the center.

The nasal septum is a wall made primarily of cartilage and bone that separates the nasal cavity into left and right passages.

When the septum deviates significantly toward one side, it may narrow that nasal passage and contribute to difficulty breathing through the nose.

A sinus CT scan can show the position and shape of the nasal septum.

However, a visible deviation does not automatically establish that it is responsible for one-sided nasal congestion.

An ENT examination can help determine whether the deviation is contributing to the patient’s symptoms.

Enlarged Turbinates

Turbinates are structures along the sidewalls of the nose that help warm, humidify, and filter inhaled air.

The tissue covering these structures may swell due to allergies, irritants, infections, or other inflammatory conditions.

A sinus CT scan may show enlarged turbinates or narrowing of the surrounding nasal passages.

However, turbinate swelling can change over time, and CT imaging captures the anatomy at a particular moment.

An ENT specialist will consider the imaging findings alongside the nasal examination and the patient’s symptoms to determine whether turbinate enlargement may be contributing to obstruction.

Nasal Polyps or Other Soft-Tissue Abnormalities

Nasal polyps are soft, painless, noncancerous growths that develop from the lining of the nasal passages or sinuses.

They may contribute to nasal congestion, difficulty breathing through the nose, impaired sinus drainage, reduced sense of smell, and postnasal drip.

A sinus CT scan may reveal soft-tissue abnormalities that could represent nasal polyps or other conditions.

However, CT imaging does not always reliably distinguish polyps from other soft-tissue abnormalities.

Depending on the findings, additional evaluation with nasal endoscopy, MRI, or biopsy may be recommended.

Persistent one-sided nasal obstruction or a suspected growth affecting only one side should be evaluated rather than automatically attributed to benign nasal polyps.

A Narrowed Sinus Drainage Pathway

Sinus drainage pathways are relatively small openings that allow mucus to drain from the sinuses into the nasal cavity.

Inflammation or certain structural changes may narrow these pathways and interfere with sinus ventilation and mucus drainage.

A sinus CT scan can help visualize these areas, including structures that cannot be fully assessed during a routine nasal examination.

However, narrowing of a sinus drainage pathway does not necessarily cause obstruction of airflow through the main nasal passages.

An ENT specialist can assess whether these findings are relevant to the patient’s sinus symptoms and whether further evaluation or treatment may be appropriate.

Findings That May Suggest Fungal Sinus Disease

A sinus CT scan may show dense material or calcifications within an affected sinus that raise suspicion for certain conditions, including a fungal ball.

Some forms of fungal sinus disease may primarily affect one sinus and be associated with one-sided symptoms.

However, these imaging findings are not specific to fungal disease, and CT imaging alone cannot confirm a fungal diagnosis.

Depending on the suspected condition, additional examination, imaging, or tissue evaluation may be necessary.

Dental-Related Sinus Inflammation

The roots of the upper teeth are located close to the maxillary sinuses.

In some cases, dental infections, extractions, implants, or other dental conditions may contribute to inflammation in a nearby sinus.

A sinus CT scan may show findings that raise suspicion for a possible dental source, particularly when abnormalities primarily affect one maxillary sinus.

However, sinus CT imaging does not replace a dedicated dental examination or dental imaging when those are needed.

An ENT specialist may recommend further evaluation by a dentist or another oral healthcare provider if a dental-related cause is suspected.

An Abnormal Growth or Mass

Most cases of one-sided nasal congestion are not caused by cancer.

However, persistent unilateral symptoms, particularly when accompanied by bleeding, facial numbness, unexplained swelling, or vision changes, may warrant additional investigation.

A sinus CT scan may identify an abnormal growth, unusual soft-tissue changes, or changes involving nearby bone.

These findings do not automatically indicate a malignant condition.

Depending on the clinical findings, additional diagnostic steps such as nasal endoscopy, MRI, or biopsy may be recommended to better understand the abnormality.

When Should One-Sided Nasal Congestion Be Evaluated by an ENT Specialist?

Consider scheduling an ENT appointment if you experience:

• Nasal or sinus symptoms that continue for several weeks despite appropriate home care or medication
• Persistent blockage affecting the same nostril
• Frequently recurring sinus infections
• Nasal congestion that interferes with sleep, breathing, work, or daily comfort
• Facial pain or pressure that consistently affects one side
• Persistent changes in your sense of smell
• Nasal drainage that is bloody, foul-smelling, or consistently occurs on one side

Persistent one-sided congestion does not necessarily indicate a serious condition. However, an ENT evaluation can help determine whether structural narrowing, inflammation, or another abnormality may be contributing.

When Should You Seek Emergency Medical Attention?

Some symptoms may indicate a more serious condition and should not be attributed to routine sinus congestion.

Seek emergency medical attention for:

• Sudden vision changes or loss of vision
• Significant swelling around the eyes, especially when accompanied by pain or vision changes
• A severe headache accompanied by fever, neck stiffness, or confusion
• New facial weakness or other sudden neurological symptoms
• Rapidly worsening facial swelling accompanied by fever or severe pain

When Should You Arrange Prompt Medical Evaluation?

Other symptoms may not require emergency care but should be assessed without unnecessary delay.

Arrange prompt medical evaluation for:

• Persistent one-sided nasal obstruction
• Recurrent bloody or foul-smelling nasal discharge
• New or unexplained facial numbness
• Persistent or worsening one-sided facial pressure
• A suspected growth affecting only one side of the nose

An ENT specialist can determine whether nasal examination, endoscopy, CT imaging, or other testing may be appropriate based on the symptoms and clinical findings.

Conclusion: Understanding One-Sided Congestion With St. Louis Sinus Center

Persistent one-sided nasal congestion can result from several possible causes, including structural differences, inflammation, sinus drainage abnormalities, and other nasal or sinus conditions.

A sinus CT scan may help identify abnormalities that cannot be fully visualized during a routine examination.

However, CT imaging alone does not always establish the cause of nasal obstruction. Results must be interpreted alongside the patient’s symptoms, medical history, and examination findings.

St. Louis Sinus Center provides ear, nose, and throat care services for patients in St. Louis and Festus, MO.

If you are experiencing persistent one-sided nasal congestion, consider scheduling an appointment with our team to explore possible underlying causes and discuss whether sinus CT imaging or another diagnostic approach may be appropriate for your individual needs.