Ultrasound scanning including color Doppler

An ultrasound scan is a widely used technique that makes use of high frequency sound waves to create images of organs and structures inside your body. It is a harmless procedure as it makes use of sound waves instead of radiation. Doppler ultrasound scans on the other hand are used to visualize blood or fluids flowing through the body.

Doppler Ultrasound

A Doppler ultrasound helps doctors by recording sound waves reflecting off fluids like blood and in turn gives a visual or audible representation of its movement through veins, arteries and blood vessels.It also helps measure their speed and other aspects of how they flow through the body.The reflected sound is useful for diagnosing conditions likeblood clots, restricted blood flow and fetal health. Doppler Ultrasound scans are carried out using a handheld device called transducer. There are three different kinds of Doppler Ultrasound - Color, Continuous and Duplex.

Unlike ultrasound imaging which is used to give parents a picture of their baby in-utero, Doppler Ultrasound technique is carried out to view blood flow in the fetus.

• Color Doppler Ultrasound: Color Doppler Ultrasound gives a view of blood flow in the fetus in the form of a picture that is created from the reflected sound waves. Instead of the sounds being converted into a graph, a coloredimage of speed of blood flow and movement is created from the sounds.
• Power Doppler Ultrasound: Power Doppler is a form of Color Doppler Ultrasound that has the ability to penetrate organs much deeper for a closer look in order to understand the blood flow inside an organ with more clarity. The resulting image is a color overlay and it also indicatesdirection and blood speed.
• Continuous Doppler Ultrasound: Continuous Doppler Ultrasound is used for a quick diagnosis of possible hindrances or restrictions to blood flow. Here the doctor uses it as an audible diagnostic tool wherein a small, portable unit is used to listen to the reflected sounds. Narrowed, open and blocked blood vessels make a certain sound that is very different from that of normal blood vessels which is considered as a differentiating factor.
• Duplex Doppler Ultrasound: The Duplex Doppler Ultrasound combines traditional ultrasound with Doppler ultrasound. Here sound waves bounce off blood vessels to create a visual picture or image. These sounds are also converted to graphs with the help of a computer program which helps doctorsunderstand the direction and speed of blood flow.

Color Doppler Test during Pregnancy

This test makes use of color codes to understand the blood flow to the fetus through blood vessels, its direction and speed. It is recommended only in cases of complicated pregnancy and is usually performed by a specialized doctor such as a radiologist or by an ultrasound technologist (sonographer) who is monitored by a radiologist. Here a probe covered with gel is placed over the pregnant womb which in turnis connected to a speaker.The doctor listens to the blood flow through the fetus's heart. If is a moving structure, then the echo comes back at a slightly different frequency (called the Doppler Effect) and this helps measure the speed of movement. Blood flowing in a blood vessel causes small echoes and these are used to measure the speed of movement of blood cells. All this allows the doctor to determine whether or not there is normal flow.

Color Doppler ultrasound makes use of a special technology to visualize the blood flowing in arteries and veins. Here the sound waves are converted to color pictures on a screen so that flow can be seen through the blood vessels (color Doppler) or on a graph showing changes in velocity.

Uses of Doppler Ultrasound during Pregnancy

Doctors make use of Doppler Ultrasound during pregnancy to monitor fetal placental blood flow, blood flow to the heart and brain and umbilical blood flow. The scan results in turn help doctors determine if restricted blood flow to the fetus is caused due to conditions like RH sensitization, sickle cell anemia and restricted blood vessels. Restricted blood flow to the fetus can cause:

• Reduced size of the baby
• Reduced birth weight
• Impaired development
• Complications of Doppler ultrasound scans

Unlike X-rays and other imaging tests which make use of radiation, these ultrasound scans are normally safe and painless as they use sound waves to generate images or sound. Hence they do not cause any kind of problems or complications.