CT Scan of the Mastoid Without Contrast
A CT scan uses X-rays to create detailed images of the mastoid portion of the temporal bone and nearby structures without IV contrast.
["This imaging test evaluates the mastoid and middle-ear region for conditions such as infection, inflammation, or bone abnormalities."]
Key facts at a glance
- LOINC
- 103881-9
- Short code
- CT Mastoid WO contr
- Synonyms
- CT Mastoid WO contr
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ct
- CPT
- 84484
- SNOMED
- 302774002
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
A CT scan of the mastoid creates detailed cross-sectional images of the mastoid, a honeycomb-like area of bone behind the outer ear. The scan may also show nearby parts of the middle and inner ear and the base of the skull.
Why might I need this test?
This test may be recommended to evaluate persistent ear symptoms, drainage from the ear, hearing changes, suspected infection, or inflammation. It can also help identify bony abnormalities, complications of ear disease, or the location and extent of a growth before treatment or surgery.
How is the test performed?
You will lie on a CT table while an X-ray machine rotates around your head. The scan is generally quick and painless. A radiologist reviews the images and sends the report to your healthcare professional.
How do I prepare for the test?
Usually, no special preparation is needed. Remove metal objects such as earrings, hairpins, and removable hearing devices before the scan, and tell the care team if you are pregnant, may be pregnant, or have metal implants. Follow any instructions provided by the imaging center.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal findings may indicate fluid or infection in the middle ear or mastoid, inflammation, bone erosion, or another structural abnormality. The results may also help assess complications of chronic ear disease. Your healthcare professional will interpret the scan together with your symptoms, examination, and other tests.
Short name
Mastoid CT Without Contrast
Frequently asked questions
Does this CT scan use contrast dye?
Is a CT scan of the mastoid painful?
Can I have this scan if I am pregnant?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy