You may have been told by your doctor that you have sinusitis. What is sinusitis?


  • Sinusitis is an infection of the paranasal sinuses; the airspaces that exist around your nasal passage. There are 4 major sinuses, the frontal, ethmoid, maxillary and sphenoid sinuses. While any of these may be involved in sinus infections, involvement of the ethmoid and maxillary are fairly typical. Sinusitis is a very common disease. Almost all people suffer from either a primary sinus infection, or involvement of the sinuses as an association with the common cold or other infections and inflammatory conditions of the nasal cavity. The symptoms may include nasal discharge, headache or facial pain, fever, and a "stuffy nose".

Why do I need an imaging study of my sinuses?

  • Very often, sinusitis is treated empirically with decongestants and aspirin or acetaminophen, or when your physician is concerned about bacterial infection with an antibiotic.  However, not all sinus disease is easily managed, and there are important potential complications from sinus disease.  You may have recurrent sinusitis, with repetitive infections in one or more sinuses, in which case more involved therapy or even surgery has been proposed.  Among the most feared complications of sinusitis are involvement of the eye and brain.  Also, the symptoms and infections of the sinuses may be chronic and unremitting in some patients.  In these cases, a study to visualize the extent of sinus disease and to depict your own individual anatomy of the sinuses may be proposed.  You may have discussed surgical management of your sinus disease, or it may be a potential therapy for your disease.

What Imaging studies are available to examine my sinuses?

  • While x-rays of the sinuses may provide occasional information regarding sinusitis, a CT scan of the sinuses is a very commonly ordered examination in the setting of recurrent acute sinusitis, or in chronic sinusitis.  A CT study can accurately show your physician the extent of involvement of the sinuses as well as accurately display your own sinus anatomy, which is widely variable between different people.  The CT study can serve as a surgical "road map" if surgery is indicated, and can also show involvement of the eye or brain. MRI of the sinuses may be also be ordered by your physician if there is expectation of serious problems involving either the eyes or brain. MRI is a very powerful tool for displaying the extent of an infection that has involved either the eye or brain, but is not as useful as a surgical map for the head and neck surgeon who may operate on the sinuses.  If you are being imaged primarily as a surgical planning tool, there is a chance that your surgeon may wish the study performed with markers positioned on your head or over your face to provide additional localization information for surgery. 

    A CT study of the sinuses has few complications, and is most often performed without the use of intravenous contrast agent.  You will be asked to lie on a table that travels into the ring of the CT scanner.  The ring contains the x-ray tube and the detectors that receive the x-rays after they gather the information.  Computers reconstruct the collected data into a series of images that the neuroradiologist and your physician can review.  The images obtained by a modern CT scanner take very little time to acquire.  You should expect to be in the scanner for no more than 10 minutes for a typical CT of the sinuses.  The major risk of this study is the exposure to radiation required to image the sinuses.  Your neuroradiologist or the technologists at the center performing the sinus CT can give you information regarding this radiation dose.  The scans are performed with a dose that is as low as reasonably achievable or “ALARA” to provide the information that your treating physician needs.

    MRI studies are performed in a powerful magnet, with a similar patient couch and a longer tube, which you will travel partially into for the examination.  The magnetic field and a series of radiofrequency pulses (somewhat like a standard radio transmitter) are used to gather information from the tissue of your body.  There is no radiation exposure, but some patients may be uncomfortable in the long, contained tube that is necessary for the MRI to function.  You should discuss potential issues of claustrophobia with your physician when you are discussing the examination. If you have metal-containing internal devices or implanted electrical medical appliances, such as cerebral aneurysm clips, spinal cord or brain stimulators, certain heart valves, cardiac pacemakers, cochlear implants, ocular metallic foreign bodies, or some types of inner ear (ossicle) prostheses, you should consult your physician before having an MRI. Certain devices or implants are not safe within the magnetic field of the MRI.  The MRI scans take considerably longer than CT, and may take 20-45 minutes for completion, during which time a technologist will be talking to you and instructing you on the progress of the scan.

    As soon as either the CT or MRI images are acquired, they will be reviewed by a neuroradiologist who is trained in the anatomy of the sinuses and in pathology that involves the sinuses, and the exam results will be transmitted to your physician.  Copies of the examination often are immediately available to your treating physician as well.  You are always free to go over the examination with the radiologists at the facility where the exam is performed, or with your surgeon after the exam reaches them. 


  • Sinusitis may be a very simple, uncomplicated disease which can be self-limited, or it can be a more involved and complicated disease. Imaging studies (CT or MRI) of the sinuses may be ordered by your physician, and provide important information for management of the process. Consultation with a neuroradiologist will insure that the proper examination is performed and the correct diagnosis is reached.