Overview
A Doppler ultrasound is an imaging test that uses sound waves to show blood moving through blood vessels. The colour doppler is a non invasive, painless procedure that doesn’t expose you to harmful radiation. The test uses a computer to change sound waves into different colors. These colors show the speed and direction of blood flow in real time.
What is it used for?
Color Doppler ultrasound tests are used to help health care providers find out if you have a condition that is reducing or blocking blood flow in the arteries or veins of your legs, arms, or neck. A reduced amount of blood flow may be due to a blockage in the artery, a blood clot inside a blood vessel, or an injury to a blood vessel. It may also be used to help diagnose certain heart diseases.
- Check heart function. It is often done along with an electrocardiogram, a test that measures electrical signals in the heart.
- Look for blockages in blood flow. Blocked blood flow in the legs can cause a condition called deep vein thrombosis (DVT)
- Check for blood vessel damage and for defects in the structure of the heart. Look for narrowing of blood vessels. Narrowed arteries in arms and legs can mean you have a condition called peripheral arterial disease (PAD). Narrowing of arteries in the neck can mean you have a condition called carotid artery stenosis.
- Monitor blood flow after surgery.
- Check for normal blood flow in a pregnant woman and her unborn baby.
Why you need a Doppler ultrasound?
You may need a Doppler ultrasound if you have symptoms of reduced blood flow or a heart disease. Symptoms vary depending on the condition causing the problem. Some common blood flow conditions and symptoms are below.
How to Prepare for a Color Doppler Ultrasound
Preparation is similar to a standard ultrasound but with a few extra considerations, especially when examining blood vessels.
- Fasting: For abdominal or renal (kidney) scans, you may be asked to fast for a certain period (e.g., 6-12 hours). This is to reduce gas and food in the digestive system, which can interfere with the sound waves and create blurry images.
- Full Bladder: For pelvic or pregnancy scans, you might be instructed to drink several glasses of water an hour before the test and avoid using the restroom. A full bladder helps to provide a better window for viewing the pelvic organs and blood vessels.
- Avoid Caffeine and Nicotine: For vascular scans, such as those of the neck (carotid) or limbs, you may be advised to avoid caffeine and nicotine for at least a few hours before the exam. These substances can constrict blood vessels, leading to inaccurate measurements of blood flow.
- Wear Loose Clothing: Wear comfortable, loose-fitting clothes that allow easy access to the area being scanned. You may need to remove jewelry or accessories.
- Medication and Medical History: Inform your doctor or the sonographer about any medications you are taking, especially blood thinners, and any relevant medical history.
How it’s Done
The procedure is very similar to a standard ultrasound.
1
Positioning:
You’ll be asked to lie down on an exam table, & clear gel is applied to the skin to remove air pockets and help transmit sound waves.
2
Preparation:
The sonographer moves a handheld transducer over the gel-covered area, sometimes producing a ‘whooshing’ sound.
3
Image Capturer:
Real-time images appear on the monitor, with color overlays showing blood flow. Measurements are taken.
4
Sensation:
The exam is painless, though you may feel cool gel, light pressure, or mild temporary discomfort.