Skip to content

Computed Tomography (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 injected contrast dye. It is commonly used to evaluate head injuries, bleeding, and other urgent neurologic concerns.

Quick summary

["This imaging test uses X-rays to examine the brain and skull without injecting contrast dye."]

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

Key facts at a glance

LOINC
36104-8
Short code
CT Head Ltd WO contr
Synonyms
CT Head Ltd 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 produces detailed pictures of the brain, skull, and nearby structures. In this version, no contrast dye is injected.

Why might I need this test?

A CT scan may be ordered to evaluate a head injury, sudden severe headache, weakness, confusion, seizures, or other changes in mental status. It can help identify bleeding, fractures, swelling, or other structural abnormalities.

How is the test performed?

You will lie on a table while an X-ray machine rotates around your head. The scan is generally quick and does not require an injection.

How do I prepare for the test?

Fasting is usually not required. Remove metal objects, such as hairpins, jewelry, and hearing aids, if instructed. Tell the imaging team if you are pregnant or may be pregnant.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Head CT without contrast

Frequently asked questions

Does a head CT without contrast use dye?
No. This test is performed without injected contrast dye. If contrast-enhanced imaging is needed, the care team will discuss that separately.
Is a head CT painful?
The test is usually painless. You may feel some pressure or hear clicking sounds from the scanner, and you may be asked to remain still.
How soon are the results available?
A radiologist typically reviews the images and sends a report to your healthcare team. The timing of the final results and discussion depends on the urgency and the care setting.
  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