About a sinus MRI scan
The sinuses are air-filled spaces in the bones of the face and skull, around and behind the nose and eyes. They are lined with a thin layer of tissue that makes mucus, which drains into the nose. A sinus MRI uses a strong magnetic field and radio waves, not X-rays, to show the sinuses and the soft tissues around them, including the eye sockets and the brain just above.
Sinusitis (sinus infection) is common and is usually diagnosed from your symptoms, without a scan. When the bony detail of the sinuses needs to be seen, for example before sinus surgery for long-term (chronic) sinusitis, a CT scan is usually used. MRI is better at showing soft tissue, so it is mainly used to:
- look at growths in the nose and sinuses, such as polyps, inverted papillomas and, rarely, cancers, and see how far they extend
- tell a sinus filled with mucus or fluid apart from a growth, which can look the same on CT
- check for complications of sinusitis spreading to the eye socket or brain
- investigate symptoms on one side only, such as a blocked nose, nosebleeds or reduced sense of smell that does not get better
Mild thickening of the sinus lining is often seen on MRI scans of the head in people with no symptoms, so the findings are always read alongside your symptoms and examination. For the bones of the face, see face and facial bones MRI, and for the brain, see brain MRI.
What happens during the scan
You lie on your back on the scanner bed with your head in a head coil, which fits around your head like a helmet but does not touch your face. The scanner is loud, so you will wear ear plugs or headphones, and the radiographer can talk to you throughout. You need to keep your head still and try not to swallow too often while the pictures are being taken. An injection of contrast dye (gadolinium) is often used when looking at a growth or a complication of infection; where contrast is needed, it is charged separately.
What the scan can show
A sinus MRI can help to look at:
- nasal polyps and other growths in the nose and sinuses
- inverted papilloma and sinus tumours
- mucus-filled cysts (mucocoeles)
- fungal sinusitis
- complications of sinusitis affecting the eye socket or brain
- the cause of one-sided nasal symptoms or loss of smell
When to get urgent help: call 999 or go to A&E if you have sinus symptoms with swelling or redness around the eye, changes to your vision, a severe headache, confusion or a stiff neck.
Preparing for your scan
No special preparation is needed, and you can eat and drink normally. Upload any previous scan reports and letters from an ENT specialist when you book. Remove any make-up around the eyes, as some types contain metal.
You can usually eat, drink and take your normal medicines unless the scanning centre tells you otherwise. Wear loose, comfortable clothing without metal zips or buttons, and leave jewellery at home. You will be asked to remove metal items such as hair clips, hearing aids, coins and keys, and you may be asked to change into a gown.
Before the scan you will complete a safety questionnaire. Tell the team if you have a pacemaker, any metal implant, surgical clips or other device, if you have kidney problems or allergies, or if you are, or might be, pregnant or breastfeeding. If you feel anxious in enclosed spaces, let us know when you book. Some centres can offer a relaxant, and if you take one you will need someone to take you home and must not drive for 24 hours.
Frequently asked questions
Do I need a scan for sinusitis?
Usually not. Most sinusitis gets better on its own and is diagnosed from your symptoms. A scan may be suggested if symptoms last a long time, keep coming back, affect one side only, or if a complication is suspected.
Is MRI or CT better for the sinuses?
CT shows the thin bones of the sinuses best and is usually used before sinus surgery. MRI shows soft tissue better, so it is used to look at growths and to check whether a problem has spread to the eye socket or brain. Your referrer will say which is needed; if you are unsure, contact us before booking.
Can MRI find nasal polyps?
Yes. MRI can show polyps and how far they extend, and helps to tell them apart from other growths. Polyps are often first seen by a doctor looking inside your nose.
Do I need a referral?
You can tell us if you have a referral from your GP, physiotherapist or consultant and upload it when you book. If you do not have one, select “no referral” when you book and the scanning centre will confirm the next steps with you.
Sources
- NHS – Sinusitis (sinus infection)
- NHS – Nasal polyps
- NHS – Nasal and sinus cancer
- RadiologyInfo.org – Sinusitis
- NHS – MRI scan
The information on this page has been gathered from various sources and is provided for general information only. It is not medical advice. TOP MRI is not liable for the accuracy or completeness of this information. Please speak to your doctor or the scanning centre about your own situation.