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CT Angiogram, Pulmonary Arteries, With Intravenous Contrast

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

A CT scan uses intravenous contrast to image the pulmonary arteries and look for blood clots, most often to evaluate a suspected pulmonary embolism.

Quick summary

["This CT scan helps determine whether a blood clot is blocking blood flow through the lungs."]

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

Key facts at a glance

LOINC
36147-7
Short code
CTA PA W contr IV
Synonyms
CTA PA W contr IV
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-angio
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?

CT pulmonary angiography is an X-ray-based CT scan that uses intravenous contrast to show the pulmonary arteries, the blood vessels that carry blood from the heart to the lungs.

Why might I need this test?

It is most often used to evaluate a possible pulmonary embolism, especially after symptoms such as sudden shortness of breath, chest pain, coughing blood, or a rapid heartbeat. It may also be used to study other abnormalities of the pulmonary blood vessels.

How is the test performed?

You lie on a table that moves through the CT scanner. IV contrast is given through a vein, and the scanner rapidly takes images of the chest. The scan usually takes a short time, and a radiologist interprets the images.

How do I prepare for the test?

Follow the imaging center's instructions, including any fasting or medication guidance. Tell the care team about prior contrast reactions, kidney disease, pregnancy or possible pregnancy, and medications such as metformin; additional instructions may be needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A finding consistent with a pulmonary embolism means a clot or obstruction is affecting blood flow through the pulmonary arteries and may require prompt treatment. A negative scan generally makes a pulmonary embolism less likely, but very small or chronic clots may not be visible, so the result must be interpreted with symptoms and other testing. The scan may also identify alternative explanations for the symptoms or unrelated abnormalities in the lungs or blood vessels.

Short name

CT pulmonary angiography

Frequently asked questions

Is CT pulmonary angiography the same as a routine CT scan?
It uses the same CT scanner, but intravenous contrast and rapid imaging are used to examine the pulmonary arteries in greater detail.
Does the test require an IV line?
Yes. IV contrast is typically injected through a vein in the arm or another suitable site before or during the scan.
Will I need to stay afterward?
Most people can leave shortly after the scan. Observation may be needed if there was a contrast reaction, significant kidney concerns, or sedation was used.
  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