An ultrasound scan, also referred to as a sonogram, diagnostic sonography, and ultrasonography, is a device that uses high frequency sound waves to create an image of some part of the inside of the body, such as the stomach, liver, heart, tendons, muscles, joints and blood vessels.
Experts say that as sound waves, rather than radiation are used, ultrasound scans are safe. Obstetric sonography is frequently used to check the baby in the womb.
Ultrasound scans are used to detect problems in the liver, heart, kidney or the abdomen. They may also be useful in helping the surgeon when carrying out some types of biopsies.
The word “ultrasound”, in physics, refers to all sound with a frequency humans cannot hear. In diagnostic sonography, the ultrasound is usually between 2 and 18 MHz. Higher frequencies provide better quality images, but are more readily absorbed by the skin and other tissue, so they cannot penetrate as deeply as lower frequencies. Lower frequencies can penetrate deeper, but the image quality is inferior.
How do ultrasound scans work?
Although ultrasound travels through soft tissue and fluids, it bounces back off denser surfaces. Ultrasound will travel through blood, for example in the heart chamber, but much of it will echo (bounce back) when hitting a heart valve.
If there are no solid gallstones in the gallbladder, ultrasound will travel straight through, but when there are stones, ultrasound will bounce back from them.
The denser the object the ultrasound hits, the more of it bounces back.
The bouncing back, or echo, is what gives the ultrasound image its features – varying shades of gray reflect different densities.
What can ultrasound scans be used for?
Ultrasound is commonly used in medicine today. Health care professionals can use sonography for either diagnosis or treatment (therapeutic procedures), as well as for guidance during procedures that require intervention, such as biopsies.
A medical professional who performs ultrasound scans is called a Sonographer. Scans, or images are then interpreted by radiologists, cardiologists, or other medical specialists. The sonographer usually holds a transducer; a hand-held device which is placed on the skin of the patient.