Post Graduate Diploma in Ultrasonography

The ultrasound image is produced by sending sound waves of 1-10 million hertz through a transducer by placing it over structures of the body. The sound waves are either absorbed or bounce back to crystals in the head of the transducer. For example, sound waves go through areas that are hollow or fluid-filled, such as the bladder and blood vessels. These areas appear black on the screen. Areas filled with tissue allow some penetration and refraction of sound and produce a grayish-white image. Really hard structures,such as bone, produce a bright white image as the sound waves completely bounce back to the transducer.

In pregnancy, this allows providers to have an image of the woman's womb. The amniotic fluid will appear black, which enhances the bones and tissues of the baby, which will appear white.