You are here 1.5 Ultrasound and Tissue Ultrasound is marked by a
number of properties when it passes through tissue. Reflection
occurs on border surfaces between tissues with different wave
propagation properties (such as fat, muscle, and blood). The
degree of reflection depends on the magnitude of this
difference. The remaining ultrasound energy may either penetrate
deeper or be absorbed by the tissue. Usually the ultrasound wave
hits several different reflector surfaces. Interaction with
tissue causes the ultrasound energy to diminish and become
weaker as it penetrates deeper. This is also known as
attenuation and is similar to sound that becomes fainter when
one moves further away from it. You will read more about
attenuation when we discuss 2D imaging and artifacts. As border
zones are usually marked by more or less irregular surfaces, the
ultrasound waves are scattered in all directions. This allows
some of the reflected ultrasound waves to return to the
transducer and be used to generate an image. |Atte