What is a cerebral angiogram?
Angiograms are very good at detecting problems with blood vessels such as an aneurysm, arteriovenous malformation (AVM), artery stenosis from plaque build-up, tumors, and clots.
What should I expect during an angiogram?
An angiogram works similar to an x-ray. The body casts a “shadow” on film when it is exposed to the x-ray, much like when you hold a flashlight up to your hand and cast a shadow on a wall. Normally your blood vessels cannot be seen in an x-ray, but adding a dye (contrast agent) into the blood stream makes your arteries and veins visible. Contrast agent contains iodine, a substance that x-rays cannot pass through.
To deliver the contrast agent, a catheter is advanced from the femoral artery in the leg to one of the four arteries in the neck that lead to the brain. The doctor steers the catheter through the blood vessels while watching a monitor. A fluoroscope machine, called a C-arm is an arc shaped piece of equipment that generates x-rays from one side and photography them on the other side. Contrast is injected into the bloodstream to make the blood vessels visible on the monitor. The result is a kind of roadmap of the arteries.
Today many catheter angiographic studies have been replaced by less invasive methods such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) that do not require a catheter be inserted. Catheter angiography has the benefit of combining diagnosis and treatment in patients who may undergo surgery or other endovascular procedures such as angioplasty, aneurysm coiling, or stent placement.
What are the risks of an angiogram?
An angiogram is an invasive test, so it is not without risk. There is a very small risk of the catheter damaging your artery or losing a piece of plaque lining the artery wall. The loose piece of plaque can travel up the artery into the brain and could block blood flow causing a stroke.
Some people are sensitive to the contrast agent used. The most common side effects from the iodine contrast are brief metallic taste in your mouth and a feeling of warmth throughout your body.
An extremely rare reaction occurs when you experience severe hives and have difficulty breathing. Medications such as antihistamines can reverse this reaction. If you have diabetes or kidney problems you may experience kidney failure, but this too is extremely rare.
Be sure to tell your doctor if you are pregnant or have a history of allergies (to medications, previous iodine injections, or shellfish), diabetes, asthma, a heart condition, kidney problems, or thyroid conditions. Also tell them if you take any blood thinning medication such as aspirin or Coumadin.