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Computed Tomography (CT) Scan of the Knee

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

A CT scan creates detailed X-ray images of the knee to help evaluate bones, joint tissue, and surrounding structures.

Quick summary

["A knee CT can help identify fractures, joint disease, and other structural problems within or around the knee."]

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

Key facts at a glance

LOINC
87878-5
Short code
CT Knee-Bl W contr IS
Synonyms
CT Knee-Bl W contr IS
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 knee CT scan uses X-rays and computer processing to create cross-sectional images of the knee. It provides detailed views of the bones, cartilage, joint space, and nearby soft tissues.

Why might I need this test?

A CT scan may be ordered to evaluate a suspected fracture, severe joint pain, swelling, injury, or abnormalities that are not clearly visible on standard X-rays. It may also be used to assess infection, a bone lesion, or the structure of the knee before treatment or surgery.

How is the test performed?

You will lie on a padded table while the CT scanner rotates around the affected knee. The scan is generally painless and usually takes only a few minutes. If your order includes intravenous contrast, a contrast injection may be used to improve the visibility of certain tissues.

How do I prepare for the test?

Wear comfortable clothing that does not cover the knee with metal. Tell the imaging staff if you are pregnant, have kidney disease, or have had a reaction to contrast dye. The facility will confirm whether your scan is being performed with or without contrast and provide any specific preparation instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Knee CT

Frequently asked questions

Is a CT scan of the knee painful?
The scan itself is usually painless. You may feel brief pressure or discomfort from the scanner, and an injection can cause a warm sensation if contrast is used.
How is a CT scan different from a regular X-ray?
A CT scan produces many detailed cross-sectional images and can show complex fractures and surrounding tissues more clearly than a standard X-ray.
Will I need contrast dye?
Some knee CT scans are performed without contrast, while others use intravenous contrast. Confirm the plan with the imaging facility, especially if you have kidney disease or a previous reaction to contrast dye.
  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