A carotid Doppler, also known as carotid duplex ultrasound, is an ultrasound exam of carotid arteries. Ultrasound is an imaging modality that uses sound waves, a transducer, and a computer to create images of the inside of the body. The Carotid arteries are the chief blood vessels that carry blood to your brain and are located on either side of your neck. A carotid Doppler is performed to determine the blood flow through the carotid arteries and to assess for the presence of any blockage due to atherosclerotic plaque or narrowing of the carotids that can hinder the blood flow resulting in the stroke. It is a non-invasive and painless test that does not use any radiation or X-rays.
Why and when do you need this test?
The formation of plaque can narrow or even block the lumen of the carotid arteries, obstructing the blood flow to the brain. A plaque is formed by a combination of fatty deposits, cholesterol, fibrin, calcium, etc., in the inner layer of the blood vessels. Your doctor may advise this test if you have risk factors associated with plaque formation. Or you show signs and symptoms of an impending stroke like TIA (transient ischemic stroke)
Some of the indications for a carotid Doppler include the following;
- Previous stroke
- Transient ischemic attack (TIA)
- To assess the position of the stent after the surgery for plaque removal
- To follow up on the progression of the plaque
- Medical history of long-standing high blood pressure, diabetes, or high cholesterol
- Family history of heart disease or stroke
- Lifestyle risk factors: Obesity, smoking, lack of exercise, poor diet, excessive alcohol use.
- Findings in the physical examination, for example, bruit (a whooshing sound in the blood flow)
- Sickle cell disease
Do you need to prepare for the test?
It is a simple test that may not need any special preparation.
- You may need to wear loose, easy clothing without a collar that should be able to expose your neck
- Do not wear a necklace or heavy pieces of jewelry
What can you expect?
- You will be asked to lie down on the table
- The radiologist or the sonographer would put some gel on your neck
- He will then put a transducer probe which looks like a microphone, over the gel.
- The transducer will transmit sound waves to the body and back from the body to the computer to form images.
- After the exam, you may return to daily activities normally.
- The procedure lasts for about 30 minutes but may take longer.
Are there any risks to this test?
It is a non-invasive, painless test that usually has no risks.
What do the test results mean?
The radiologist or sonographer will send a signed report to your doctor. Your doctor could tell you if the report shows any blockage or narrowing. It is usually defined in percentages. For example, your doctor may tell you that your carotid artery is 50% blocked, etc. the more the blockage, the higher the risks of stroke. Your doctor will decide your future course depending upon your results. If you have more than 60% blockage, you may need surgery to remove the plaque. If you have less than 50% blockage, your doctor may advise you to improve your lifestyle habits and may prescribe some medicines to dissolve or decrease the formation of plaques.
Other related tests may include:
- CT angiography
- MR angiography