Colour Doppler Ultrasound

A colour Doppler test is performed to evaluate the functioning of blood vessels (arteries and veins). It helps in:

• Monitoring blood flow through various organs of the body (liver, kidneys, etc.)
• Detecting blood clots in the major veins of legs or arms (deep vein thrombosis [DVT])
• Identifying blockages, such as stenosis, plaques or emboli
• Determining the fitness level of an individual for cardiac procedures, such as angioplasty
• Determining the presence of an aneurysm
• Evaluating the patency of the graft after bypass surgery to check if the graft is obstructing blood flow
• Evaluating varicose veins

In case of children, colour Doppler is helpful in finding an artery or vein for inserting a catheter or needle. It also aids in detecting congenital vascular malformations.

Additionally, a Colour Doppler is used for diagnosing the following conditions:

• Arterial occlusion
• Blood clot
• Renal vascular disease
• Abdominal aorta aneurysm
• Carotid occlusion
• Varicose veins
• Venous insufficiency

Colour Doppler test needs specific preparations depending on the organs or areas of the body to be tested. 

Colour Doppler of the extremities (arms and legs) does not require any special preparations, whereas about eight hours of fasting is required for doppler scan of abdominal organs (Sips of water are allowed if certain regular medicines need to be taken) and six hours of fasting for aortic or vena cava Doppler.

A transducer device is used for this test. The device looks like a microphone. It sends sound waves into body parts. Before starting the procedure, a clear water-based gel is applied over the area that needs to be examined. The gel helps in easy movement of the transducer over the body part and eliminates air between the skin and transducer. The transducer is gently moved over the area that needs to be examined, and images are taken from various angles for better evaluation.

A colour Doppler evaluation is a simple and harmless procedure that takes about 30-45 minutes. It is painless, noninvasive and does not involve any risk.

Normal results: Normal results are indicated by unobstructed blood flow through the examined arteries or veins and absence of blockages.

Abnormal results: Presence of a clot or obstruction in an artery or a vein or presence of blockages or narrowing of an artery or a vein indicate abnormal results.

Depending on the area scanned, abnormal colour Doppler test results may indicate conditions such as:

• DVT
• Arterial occlusion
• Varicose veins
• Venous insufficiency
• Renal vascular disease
• Arterial occlusion

Definitive or diagnosing investigations are carried out when abnormal results are obtained from a colour doppler test. Unlike doppler scan, a majority of these investigations are either invasive - catheter angiography, which involves the injection of a contrast agent, to identify the location of the blockage or minimally invasive - computed tomography (CT)-based angiography, which involves injecting a contrast agent to evaluate blood flow. However, depending on the condition to be diagnosed, your doctor may also suggest noninvasive investigations such as magnetic resonance imaging-based angiography or MRA.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.