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Catheter Angiography (CA)

A catheter angiography (CA) is a minimally invasive test that uses x-rays and a contrast material to produce pictures of blood vessels for diagnosis and treatment.

Angiograms are done to detect or confirm abnormalities within the blood vessels in the brain, including:

  • An aneurysm, bulge or sac that develops in an artery due to weakness of the arterial wall
  • Arteriovenous malformation, a tangle of dilated blood vessels that disrupts normal blood flow in the brain
  • Carotid stenosis, narrowing of the carotid arteries
  • Brain tumour
  • Blood clot
  • Vasculitis, an inflammation of the blood vessels
  • Vascular dissection, a tear in the artery wall
  • Stroke
  • Evaluation of arteries of the brain and neck before surgery
  • In preparation for minimally invasive treatment of a vessel abnormality
  • Additional information on abnormalities seen on Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scans

Frequently Asked Questions

How should I prepare for the procedure?

  • Inform our staff if you are/have:
    • Pregnant
    • Any allergies, especially to contrast materials or anaesthetic medications
  • You may be advised to stop certain medications like aspirin and blood thinners
  • Do not eat or drink for 4 to 6 hours before the test
  • Breastfeeding patients may consider pumping milk ahead of time
  • Have a relative or friend accompany you

What to expect during the procedure?

  • Your doctor would have discussed this test with you in advance and a written consent will be needed
  • Before the test, empty your bladder
  • Devices will be used to monitor your blood pressure, breathing and heart rate
  • Next, you will be asked to lie down where your groin area is shaved and cleaned. You will be covered from
    the shoulders down with a sterile drape
  • Local anaesthetic will be given at the groin

Figure 1 Preparation for CA

  • A small cut is made in the skin for a long, thin and hollow plastic tube (catheter) to be inserted
  • Contrast material is injected through the catheter. You may feel a hot sensation and a metallic taste in your
    mouth that lasts a few seconds
  • Images are taken using x-rays
  • After the test, the catheter is removed and the wound is bandaged
  • The test may take up to an hour but may vary. Remain still throughout the test

What happens after the procedure?

  • You will be sent to your ward
  • For the next 6 hours, lie down and keep your legs straight to prevent bleeding from the wound
  • Inform the nurse if there is bleeding, swelling or pain at the site where the catheter was inserted
  • You may resume your normal diet immediately or as advised by your doctor
  • You may engage in light activities 6 hours after the test, but avoid exercise and strenuous activities for 3 days

Other procedures may follow after a CA:


  • Closing the aneurysm by filling it with a material (coil, or flow-diverting stent) to reduce the risk of bleeding
  • Blocking abnormal blood vessels to reduce blood supply in patients with tumour before surgery

Figure 2 Closing an aneurysm sac by filling it with a coil

Endovascular Therapy

  • Non-surgical treatment for the sudden loss of brain function due to blood clots

Carotid Stenting

  • Deployment of a metal mesh tube (stent) into the carotid artery to treat narrowing of the vessel and decrease the risk of stroke

Figure 3 Stent in vessel

What are the benefits, risks and limitations?


  • No radiation remains in the body after the scan
  • Usually no side effects
  • Use of a catheter makes it possible to combine diagnosis and treatment in a single procedure
  • Detailed, clear and accurate images of blood vessels in the brain
  • May produce more accurate results than a Carotid Doppler Ultrasound or other non-invasive methods


  • Bruising/bleeding at the wound
  • Injury to the blood vessel
  • Kidney damage in patients with impaired kidney function
  • Allergy to contrast medium
  • Infection
  • Stroke if the catheter dislodges plaque from a vessel wall that blocks blood flow within the brain, but it is rare


  • Patients with impaired kidney function and/or allergy to contrast materials may not be suitable for this test
  • Pregnant patients are advised not to have a CA unless necessary