CT Paranasal Sinuses (often called CT PNS) is a specialized CT scan used to get detailed images of the paranasal sinuses. The paranasal sinuses are small, air-filled spaces in the bones around your nose that connect with the back of your throat.
This scan is very helpful in diagnosing sinus infections, blockages, polyps, fractures, or tumors that cannot be fully evaluated by a simple X-ray.
Common Indications for CT PNS
Doctors may request a CT PNS for:
- Chronic or recurrent sinus infections that don’t respond to treatment
- Persistent nasal blockage or discharge
- Headaches or facial pain suspected to be sinus-related
- Nasal polyps or growths
- Planning for sinus surgery (FESS) or follow-up after surgery
- Facial trauma — suspected fractures around the nose or orbits
- Congenital sinus or nasal abnormalities
- Evaluation for suspected tumor or mass
What does a CT scanner look like?
The scanner looks like a large doughnut. You lie on a flat table that slides through the scanner while it takes quick, detailed images of your sinuses.
What happens during a CT PNS procedure?
- You will lie flat, usually on your back, with your head positioned carefully.
- The table moves slowly through the scanner while images are taken.
- You need to stay very still to avoid motion blur.
Do I need to prepare for a CT PNS scan?
No special preparation is usually required.
- You can eat and drink normally.
- You may be asked to remove eyeglasses, earrings, or hairpins to avoid image interference.
Will contrast dye be used?
Usually no, most CT PNS scans are done without contrast.
However, contrast may be used if your doctor wants to check for:
- Tumors or masses
- Complicated infections (like abscesses)
- Involvement of blood vessels or surrounding structures
If contrast is needed
If contrast is needed, it is injected through a vein. Kidney-function testing is based on risk factors and local policy rather than being required for everyone.
How long does a CT PNS scan take?
The scan itself usually takes less than 5 – 10 minutes.
Is CT PNS safe?
Yes, the radiation dose is relatively low and localized to the sinus area.
Pregnancy Precaution
If you are or might be pregnant, inform your doctor and the radiographer before the scan.
Does the scan hurt?
No, the scan is painless. You just need to remain still during the scan.
What does CT PNS show?
It provides detailed images of:
- Sinus cavities (for infection, fluid, thickening)
- Nasal septum (for deviation)
- Polyps or masses
- Bone structures (for fractures or bony blockage)
Are there alternatives to CT PNS?
Yes, a simple sinus X-ray can be done but is far less detailed.
MRI may be used if there is concern about soft-tissue masses, but CT is preferred for bone detail and surgical planning.
Sources and further reading
Conclusion
CT PNS is a fast, painless, and highly accurate way to evaluate your sinuses and surrounding structures. It helps your doctor detect infections, blockages, or growths and is an important tool in planning treatment or surgery when needed.