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CT Scan of the Head Without Contrast

Published: August 9, 2026Updated: August 16, 2026

A CT scan creates detailed images of the brain and skull without using an injected contrast dye.

Quick summary

["This test uses X-rays to evaluate the brain and skull and does not require injected contrast dye."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
30799-1
Short code
CT Head WO contr
Synonyms
CT Head WO contr
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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 head CT is an X-ray-based imaging test that creates detailed pictures of the brain, skull, and nearby structures. This version is performed without injecting an iodine-based contrast dye.

Why might I need this test?

Your clinician may order this test to evaluate head injuries, severe headache, confusion, weakness, seizures, or suspected bleeding in the brain. It may also help identify conditions affecting the skull or brain tissue.

How is the test performed?

You will lie on a table while a CT scanner takes X-ray images from different angles. The procedure is generally quick and does not require injected contrast dye.

How do I prepare for the test?

Usually no special preparation is needed. Tell the imaging staff if you are pregnant, may be pregnant, or have metal implants, removable dental work, or other devices in your body.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Head CT Without Contrast

Frequently asked questions

Does this test use contrast dye?
No. A head CT without contrast does not require injected iodine-based contrast dye.
Is a CT scan the same as a standard X-ray?
No. CT uses multiple X-ray images taken from different angles and combines them to create detailed cross-sectional pictures.
How long does the test take?
The scan itself is usually brief, although check-in and preparation may take additional time. The imaging center can provide a more specific estimate.
  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 16, 2026. · Read our editorial policy