Computed tomography (CT) of the sinuses is a special noninvasive X-ray scan used to detect and diagnose health problems in the paranasal sinus cavities (commonly called “sinuses”). The sinuses are air-filled spaces in the bones found behind the cheeks, bridge of nose, and forehead. Sinus CT can help determine if you have sinusitis or other abnormality involving the sinuses.
Although uncommon, your doctor may order a sinus CT with intravenous (IV) contrast. This allows for better visualization of blood vessels and other structures. Please refer to the Computed Tomography section for more details about CT scanning and the associated risks and benefits.
Doctors may order a sinus CT to help evaluate symptoms associated with the sinuses. For example, if you have chronic sinus congestion, sinus CT can help confirm the diagnosis of sinusitis. Disorders of the sinuses that can be evaluated by CT scan include:
- Sinusitis – Caused by inflammation and/or infection of the sinuses.
- Sinus fluid – Abnormal collection of fluid in the sinuses. Also, sinus membranes may be thickened.
- Inflammation – Inflammatory disease may be detected by CT sinus.
- Tumors – Nasal cavity and sinus tumors can be identified by CT scan.
Sinus CT may also be recommended when planning for sinus surgery, radiation therapy, or biopsy.
- Sinus CT scan is fast, noninvasive, accurate, and painless.
- In a single scan, sinus CT can evaluate structures, soft tissue, bones, and blood vessels.
- When compared to MRI scan, CT scanning is not affected as much by patient movement.
- Unlike MRI, if you have metal in your body (shrapnel, bullets, needles, etc.) or an implanted medical device, you can still have a sinus CT since no magnets are used in the procedure.
- X-rays used in CT scans have no immediate side effects and do not remain in the body.
- Excessive radiation can increase the risk for cancer. However, the amount of radiation received from sinus CT alone is unlikely to cause cancer or increase cancer risk significantly.
- If you have a history of allergy to iodine-based contrast, you may need to take a steroid medication up to 12 hours before your CT. Inform your doctor if you have any contrast allergies.
- If you have a history of kidney dysfunction or failure, contrast may worsen your kidney function. Consult with your doctor about this risk if you have kidney disease.
- Pregnant women should be aware of the risk of radiation to the developing child. Doctors may recommend a different test instead of CT. For more details, please refer to the section What if I am pregnant? Can I still have a CT scan? below.
If you are, or think you are pregnant, be sure to notify your doctor or technologist before undergoing a CT scan. The amount of radiation received during a CT scan is unlikely to harm you or your baby. However, in general, CT scans are not recommended in pregnant women. In every case, the mother’s health must be considered as well. The benefit to the pregnant woman of having the CT scan to diagnose an illness may outweigh the small amount of risk to the baby from a low-dose CT scan.
The part of your body being scanned should also be considered. For example, brain CT exposes the unborn baby to little or no radiation. Even if the fetus is directly exposed to CT scan radiation (such as in CT scans of the abdomen or pelvis), the increased risk of developing cancer later in life is one in 1000. Some doctors may recommend another type of exam (ultrasound or MRI) to avoid exposing your baby to radiation.
The ACR states that current information suggests breastfeeding is safe after the use of intravenous contrast. Please discuss your breastfeeding options with your medical provider.
For more information on contrast, please see About CT Contrast.
- Sinus CT is available at multiple ARA imaging centers and takes a total of about 10 to 15 minutes.
- You may be asked to change into a hospital gown, however, for sinus CT this may not be necessary.
- Since metal can distort the CT images, all metal objects and jewelry should be removed prior to the procedure. This may include hearing aids, removable dental prostheses, eyeglasses, piercings, hairpins, etc.
- The CT scanner is a large box shaped machine with a large hole in the middle.
- You’ll be placed on a moveable exam table which may have straps or bolsters to help keep your head and body from moving. You will need to remain as still as possible so the images will be clear.
- If your study requires intravenous (IV) contrast, your paramedic or technologist will place an IV line into your arm or hand to administer the contrast. IV placement may be uncomfortable and may cause bruising later. A saline solution drip may be used to help keep the IV line clear.
- The technologist will leave the CT scan room where you are and conduct the exam from a computer in a nearby room. You will be able to talk with the technologist at all times.
- The table will make a first quick pass through the scanner to set your body position. Next, the table will move you into the scanner more slowly while the CT images are being taken. It may require several passes through the machine to complete the scan.
- You may hear slight buzzing, clicking or rotating sounds during the scanning process.
- You may be asked to hold your breath during some parts of the scan. Breathing or any other movement can distort the images.
- When the scan is finished, you may be asked to wait a few minutes while the technologist checks the quality of the images. If needed, more images may be taken.
- Wear comfortable, loose fitting clothing. You may want to leave all jewelry, piercings, and any other metal objects at home.
- If your exam requires contrast, you will be asked not to eat or drink for a few hours prior to the CT scan. In most cases, you should take all your medications as usual. Ask your doctor for specific directions about your daily medications.
- Be sure to tell your health care provider, ARA scheduler, and ARA technologist about any illness or allergies you may have. Health care providers should know if you have asthma, multiple myeloma, heart, kidney, or thyroid issues, or if you have diabetes. Also, provide a list of your current medications.
- Inform your radiologist if you are pregnant. Although the risk of sinus CT is very low for the unborn baby, your doctor may choose an alternate exam. Depending on the circumstances, both the physician and patient may decide it is necessary to go ahead with the CT scan. Also, pregnant women should not receive IV contrast unless the benefits clearly outweigh the risks. For more details, please refer to the section What if I am pregnant? Can I still have a CT scan?
- Sinus CT is fast and painless. If you feel like you might be anxious during the exam, tell your scheduler. ARA technologists and our clinical staff are experts at helping people through CT exams with minimum anxiety.
- You can return to your normal activities after the exam. Drinking plenty of water will help flush the contrast agent from your system.
A radiologist, a physician specifically trained to interpret radiological examinations, will analyze the images and send a signed report to the provider who referred you to ARA. The physician will then share the results with you.