A CT scan of the face produces images that also show a patient's paranasal sinus cavities. The paranasal sinuses are hollow, air-filled spaces located within the bones of the face and surrounding the nasal cavity, a system of air channels connecting the nose with the back of the throat. There are four pairs of sinuses, each connected to the nasal cavity by small openings.
CT scanning provides more detailed information on head injuries, stroke, brain tumors and other brain diseases than regular radiographs (x-rays).
What are some common uses of the examination?
CT scanning of the head is typically used to detect:
- bleeding, brain injury and skull fractures in patients with head injuries
- bleeding caused by a ruptured or leaking aneurysm in a patient with a sudden severe headache
- a blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke
- brain tumors
- enlarged brain cavities (ventricles) in patients with hydrocephalus
- diseases or malformations of the skull
- SinusesA CT scan of the sinuses is primarily used to:
- detect the presence of inflammatory diseases.
- plan for surgery by defining anatomy or giving further information about tumours of the nasal cavity and sinuses.
- evaluate sinuses that are filled with fluid or thickened sinus membranes.
- help diagnose sinusitis.
- Other Areas
A CT scan for the head and neck can also be used to:
- evaluate the extent of bone and soft tissue damage in patients with facial trauma, and planning surgical reconstruction
- diagnose diseases of the temporal bone on the side of the skull, which may be causing hearing problems.
- determine whether inflammation or other changes are present in the paranasal sinuses
- plan radiation therapy for cancer of the brain or other tissues.
- guide the passage of a needle used to obtain a tissue sample (biopsy) from the brain
- assess aneurysms or arteriovenous malformations through a technique called CT angiography
- Wear comfortable, loose-fitting clothing.
- Remove metal objects such as jewellery, glasses, dentures, hairpins, underwire bras and piercings.
- Bring a list of any allergies and current medications and inform your doctor of them in advance of appointment.
- Inform your doctor of any recent illnesses or medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems.
- Inform the Radiologist if you have asthma, multiple myeloma or any disorder of the heart, kidneys or thyroid gland, or if you have diabetes—particularly if you are taking a medication called Glucophage.
- Women should inform their Doctor and the Radiologist if there is a posibility that they are pregnant.
Image courtesty of Siemens Healthcare
What will I experience during my scan?
CT exams are generally painless, fast and easy. With multi-detector CT, the amount of time that the patient needs to lie still for is reduced.
When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are properly positioned. With modern CT scanners, you will hear only slight buzzing, clicking and whirring sounds as the CT scanner's internal parts, not usually visible to you, revolve around you during the imaging process.
You will be alone in the examination room during the CT scan, unless due to specific circumstances you require someone present. However, the radiographer will always be able to see, hear and speak with you through a built-in intercom system.
Occasionally a contrast material is used via an intravenous line through your arm. You will feel a pin prick when the needle is inserted into your vein. You will likely have a warm, flushed sensation during the injection of the contrast material and a metallic taste in your mouth that lasts for at most a minute or two. You may experience a sensation like you have to urinate; however, this is actually a contrast effect and subsides quickly. In the majority of cases contrast is not required in this type of examination.
After a CT exam, if an intravenous line was used to inject contrast material through your vein, it will be removed and you can return to your normal activities
Who interprets the results and how do I receive them?
A Consultant Radiologist with expertise in supervising and interpreting radiology examinations will analyse the images and send an official report to your referring physician, who will discuss the results with you.
Follow-up examinations may be necessary, and your doctor will explain the reason why. Sometimes a follow-up examination is carried out because a suspicious or questionable finding needs clarification with the advice of another physician or a special imaging technique. It may also be necessary for monitoring any abnormality over a period of time to determine if it is stable or has changed.