In: Biology
Why ultrasound images of bones are distorted? Why there is no such an effect on images of air-cavities?
Ans. Ultrasound images of bones are distorted by the principle of Reflection of sound waves.
Ultrasound is performed by generating high frequency sound waves Ii.e 5 -10KHz, and directed them through body tissues using a probe held on skin ,further it also contain a receiver to detect sound waves from tissues. Further there are some material such as bone or metal can block or distort the sound wave encounters a tissue that absorbs or transmits the sound and a wave is reflected back to the probe (reflect echoes) and appears bright white on an ultrasound (that translates the waves into images).
These obstructive materials are known as aberrating layers and cause all kinds of problems for medical professionals when trying to image and diagnose patients.
Air cavities:-
No distortion in the case of image of Air cavities. Due to uniform travelling of sound waves through uniform substances i.e air, water, oil, etc without any resist and therefore no echoes are generated.The image seen on the screen is black .