1. CT Pulmonary angiogram (CTPA)
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2. At a glance …
Medical diagnostic test that employs computed
tomography to obtain an image of the pulmonary
arteries.
 CT offers a method of direct visualization of the
pulmonary vessels and lung parenchyma (structure in
the lungs that permits gas exchange) using diagnostic
x-ray images.
 Main use is to diagnose pulmonary embolism(PE).
 Uses a special dye (contrast material) and x-rays to see
how blood flows through the lungs.
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3. Why the Test is Performed?
 The test is used to detect blood clots (pulmonary
embolism)
 May also be used to help your doctor diagnose:
• AV malformations of the lung
• Congenital (present from birth) narrowing of the
pulmonary vessels
• Pulmonary artery aneurysms
• Pulmonary hypertension - high blood pressure in the
arteries of the lungs
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4. Pulmonary embolism
Blockage of the pulmonary artery by foreign
matter or by a blood clot
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5. Arteriovenous malformation of the lung
Arteriovenous malformation or AVM is an abnormal
connection between arteries and veins, bypassing
the capillary system
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6. Pulmonary artery aneurysm
An excessive localized swelling of the wall of pulmonary
artery.
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How to Prepare for the Test?
 You should not eat or drink anything for 6
- 8 hours before the test.
 Health care provider need to be informed :
• If the patient is pregnant.
• If the patient ever had any allergic reactions to
x-ray contrast material or iodine substances.
• If the patient is allergic to any medications.
• Which medications patient is taking .
• If the patient ever had any bleeding problems.

8. How the Test is Performed ?
 Performed in the radiology department scanning room
 Patient lying flat (supine) on a CT table
 A timed intravenous injection of contrast media allows for
evaluation for pulmonary emboli.
 CT scanner gantry (donut) passes over and around the
patient to perform the scan. The gantry travels over the
patient from the neck to the abdomen to create the scan.
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9. How the Test is Performed ?(cont..)
 Timing is essential and the radiographer will use
instructions to indicate when to breathe in, breath out
or hold breath.
 Intravenous contrast is used to highlight the pulmonary
vessels, and to determine the presence of a clot in the
lung. If the patient lies very still, and the chest is
stationary (breath hold) this optimizes the quality of the
scan.
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10. Gantry(donut)
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11. Example of a CTPA
 demonstrating a saddle embolus. The white area above the
center is the pulmonary artery, opacified by radio contrast.
 Inside it, the grey matter is blood clot.
 The black areas on either side are the lungs, with around it the
chest wall.
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12. Risks
 Allergic reaction to the contrast dye.
 Damage to the blood vessel as the needle and catheter
are inserted.
 Blood clot traveling to the lungs, causing an embolism
 Excessive bleeding or a blood clot where the catheter is
inserted, which can reduce blood flow to the leg.
 Heart attack or stroke.
 Hematoma (a collection of blood at the site of the needle
puncture).
 Injury to the nerves at the puncture site
 Kidney damage from the dye.
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13. Advantages
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Sensitivity
Specificity
Lesser volume of contrast needed
Can be done in out patient basis
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14. References
 http://www.nlm.nih.gov/medlineplus/ency/article/003813.htm
 http://healthengine.com.au/info/CT_Pulmonary_Angiogram
 http://en.wikipedia.org/wiki/CT_pulmonary_angiogram
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