Page Summary
- A CT scan shows the bones and anatomy of the nose and sinuses, while an MRI shows the soft tissues and the skull base in more detail.
- Which scan is used depends on the condition, and in some situations both are needed.
CT and MRI scans are two different types of imaging. We may use one of them to look closely at your sinuses or skull base. They're not needed for every patient. We order them only when a closer look is needed than an exam alone can give.
CT Scan
A CT (computed tomography) scan uses X-rays to build a detailed picture of your sinuses and the bones around them. It's the standard way to see the shape of your sinuses, how much inflammation is there, and any blockages. This is usually the main imaging test used to plan sinus surgery.
What to expect: a CT scan is quick, usually just a few minutes. A routine sinus CT doesn't need any needles or injections.
What is an MRI?
An MRI (magnetic resonance imaging) scan uses a magnetic field rather than X-rays to provide detailed images of the brain, nerves, and tissues around the skull base.
What to expect: an MRI takes longer than a CT, usually 30–45 minutes, and means lying still inside a scanner. Some MRI scans use an injected dye to show certain tissues more clearly.
If you are claustrophobic, let your doctor know before the MRI. Simple arrangements or medication may help make the scan more comfortable if needed.
Your doctor may request an MRI when more detail is needed, such as when evaluating areas close to the eye, brain, or nerves; some cerebrospinal fluid (CSF) leaks; complex chronic sinusitis with skull base erosion; or tumors of the nose, sinuses, or skull base.