CT Pulmonary Angiography with Intravenous Contrast
A CT scan that uses intravenous contrast to examine the pulmonary arteries, often to look for a blood clot causing a pulmonary embolism.
["This imaging test can identify blood clots and other problems in the arteries carrying blood from the heart to the lungs."]
Key facts at a glance
- LOINC
- 87840-5
- Short code
- CTA CA+PA W contr IV
- Synonyms
- CTA CA+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, or CTPA, is an X-ray-based CT scan that creates detailed pictures of the pulmonary arteries. Intravenous contrast is used to make the blood vessels easier to see.
Why might I need this test?
This test is commonly used when a pulmonary embolism is suspected, especially with sudden shortness of breath, chest pain, coughing blood, or a rapid heartbeat. It may also be used to evaluate other abnormalities of the pulmonary blood vessels.
How is the test performed?
An intravenous line is placed in a vein, usually in the arm, and contrast is injected while you lie on a CT scanner. The scanner takes rapid images as the contrast moves through your bloodstream, so it is important to remain still and follow the technologist's instructions.
How do I prepare for the test?
Follow the instructions provided by the imaging center. Fasting is often not required, but your care team may request it for certain situations. Tell the care team about any contrast allergy, kidney disease, pregnancy possibility, or prior contrast reaction before the scan.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The scan may show a blood clot blocking a pulmonary artery, which can confirm a pulmonary embolism. It may also reveal narrowing, aneurysms, or other vascular abnormalities. Results should be interpreted together with symptoms, examination findings, and other tests because some abnormalities may be unrelated to the reason for imaging.
Short name
CT pulmonary angiogram (CTPA)
Frequently asked questions
Does a CT pulmonary angiogram use radiation and contrast?
Is this the same as a routine CT scan of the chest?
What should I do if I have an allergy to iodine or contrast?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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