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CRMA
CT · By region

Sinus CT scan

Allows a detailed study of the paranasal sinuses and the nasal cavities. It is often requested for chronic or recurrent sinusitis, for nasal obstruction and to plan nasal and sinus surgery.

Duration5–10 min
EquipmentPhilips 128-slice
ContrastRarely
PreparationNo fasting
CRMA's Computed Tomography (CT) scanner, in Faro
In summary

A sinus CT scan — also known as a CT of the paranasal sinuses or of the face — is a very fast exam that uses X-rays to obtain detailed images of the maxillary, ethmoid, frontal and sphenoid sinuses and of the nasal cavities. It is often requested for chronic or recurrent sinusitis and to plan nasal and sinus surgery. At CRMA, in Faro, it is performed on a 128-slice scanner and takes about 5 to 10 minutes.

What is assessed in a sinus CT scan?

A sinus CT scan allows assessment of the four pairs of paranasal sinusesmaxillary, ethmoid, frontal and sphenoid —, the nasal cavities, the nasal septum and the drainage structures (the ostiomeatal complex), as well as the surrounding bony walls. It is the reference imaging exam for the anatomical study of this region.

It allows characterisation of mucosal thickening, filling of the sinuses (secretions, polyps), anatomical variants that predispose to obstruction and post-surgical changes — information that is useful to the ENT specialist, particularly in planning endoscopic sinus surgery. The report is produced by a radiologist; the clinical interpretation rests with your doctor.

Sinus CT scan: axial, coronal and sagittal slices of the paranasal sinuses, in a bone window.

When it is requested

  • Chronic or recurrent sinusitis — characterisation of the extent and of the causes of obstruction.
  • Persistent nasal obstruction — deviated septum, anatomical variants, polyps.
  • Planning endoscopic sinus surgery (FESS) — an anatomical map for the surgeon.
  • Assessment after surgery of the paranasal sinuses.
  • Headache in the region of the face, according to clinical guidance.
  • Changes in the sense of smell, according to clinical guidance.
  • Targeted study of the maxillary sinuses — including in the context of disease of dental origin.

What the exam is like

  • 1Before

    Reception

    Arrive 15 minutes early, with your referral and previous exams, if you have them.

  • 2

    Preparation

    You remove only the metal objects from the head area: hairpins, earrings, piercings, glasses, removable dentures. As a rule, you keep your own clothes on.

  • 3

    Positioning

    Lying on your back on the table, with your head in a dedicated support.

  • 45–10 min

    Image acquisition

    The table moves through the scanner's open ring. You just need to keep your head still for a few brief moments — acquisition takes seconds.

  • 5

    Finishing

    You can leave, drive and resume your normal day straight away.

Preparation

  • Fasting: not needed (the exam is usually without contrast).
  • Contrast: rarely needed. If your referral indicates it, 4 hours' fasting and the kidney-function recommendations apply (recent blood tests from 3 to 6 months, if you have them) — we let you know when booking.
  • Medication: keep your regular medication.
  • Metal objects: remove only those from the area being studied — hairpins, earrings, piercings, glasses, removable dentures.
  • Clothing: as a rule, you keep your own clothes on.
  • A cold on the day of the exam: an acute cold can temporarily change the appearance of the lining. If you have a heavy cold, talk to us — together with your doctor's guidance, we assess whether to keep the date.
  • Pregnancy: CT uses X-rays. If you are or think you may be pregnant, always let us know before the exam.
  • Children: let us know when booking, so we can prepare the exam and adjust the protocol.
  • Documents: referral, insurer/scheme card (if applicable), previous exams (X-ray/CT).

Results

The report is produced by a radiologist from the images. The report is available as a PDF (by email or printed) and the images on CD and on CRMA's imaging platform, to take to your doctor.

Frequently asked questions

About sinus CT scans.

Does a sinus CT scan hurt?

No. It is a painless, very fast exam — image acquisition takes seconds.

Is a CT scan the same as a CAT scan?

Yes. CT (computed tomography) and CAT (computed axial tomography) are names for the same exam — CAT is the older term, while CT is the term used today. You may come across both: the exam is exactly the same.

How long does it take?

In general, 5 to 10 minutes in total, including positioning.

Do I need any preparation?

No. Fasting is not needed and you keep your regular medication. You just remove metal objects from the head area, such as earrings, hairpins, glasses or removable dentures.

Will I need contrast?

Rarely. A sinus CT scan is usually performed without contrast. If your referral indicates it, we let you know when booking.

Is CT radiation dangerous?

CT uses X-rays. At CRMA, protocols are adjusted to use the minimum dose needed for diagnostic quality, on a recent 128-slice scanner (2026). The exam is performed when the clinical benefit of the information it provides justifies the exposure.

I have a cold. Should I still have the exam?

An acute cold can temporarily change the appearance of the nasal lining and of the sinuses. If you have a heavy cold on the day of the exam, talk to us — together with your doctor's guidance, we assess whether to keep the date.

What's the difference between a sinus CT scan and an X-ray?

An X-ray gives a general, overlapping view; CT shows the sinuses in thin slices, with great detail of the bone and the lining, including the drainage pathways. That is why it is the reference exam in the study of this region.

Can I have a CT scan if I'm pregnant?

CT uses X-rays and, in pregnancy, is only performed when the clinical benefit justifies it, by medical decision. Always let us know, before the exam, if you are or think you may be pregnant.

Ready to book?

Book your sinus CT scan at CRMA.

In Faro, with personal service in PT, EN and FR. We'll confirm your booking with you during working hours.