Skip to content

CT Scan of the Mastoid with Intravenous Contrast

Published: August 9, 2026Updated: August 17, 2026

A CT scan uses X-rays and intravenous contrast to create detailed images of the mastoid and nearby structures in the temporal bones.

Quick summary

["This imaging test helps evaluate the mastoid and middle-ear region for infection, inflammation, injury, tumors, and other structural problems."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
87900-7
Short code
CT Mastoid W contr IV
Synonyms
CT Mastoid W contr IV
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?

This is a computed tomography (CT) scan of the mastoid, the honeycomb-like bone behind the ear. Intravenous contrast may be given through a vein to improve the visibility of blood vessels, inflammation, and certain abnormalities.

Why might I need this test?

The scan may be ordered to investigate persistent ear drainage, hearing changes, ear pain, or complications of an infection. It can also assess fractures, tumors, congenital abnormalities, and the location of infection before or after ear surgery.

How is the test performed?

You will lie on a table while a CT scanner rotates around your head and takes X-ray images. If contrast is required, it is usually injected into a vein in your arm; the scan itself is generally painless and takes a relatively short time.

How do I prepare for the test?

Follow the instructions provided by the imaging center, including removing metal objects and telling the care team about contrast allergies, kidney disease, or pregnancy. Ask how to handle diabetes medications, especially if you take metformin, and whether any prescribed medicines should be temporarily stopped.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CT Mastoid with IV Contrast

Frequently asked questions

Is this the same as a routine CT scan?
No. This CT focuses specifically on the mastoid and nearby structures in the temporal bones. Intravenous contrast may be used to make certain abnormalities easier to identify.
Does the scan involve radiation?
Yes. CT scans use a small amount of ionizing radiation, and the dose is selected for the specific examination being performed.
Can I have the test if I am allergic to iodine-based contrast?
Tell the imaging team about any previous contrast reaction before the appointment. The team can assess the allergy and determine whether the examination should be modified or performed with special precautions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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