QUICK CONCEPT : ACOUSTIC SHADOWING
If you have spent any time in Texas during the summer months, you will appreciate the value of shadowing – or the more popular descriptive term: shade.
While the fact that it is HOT in Texas is no revelation, the understanding of how sound (similarly to light) can generate a ‘shadow’ has relevant clinical importance.
SHADOWING ARTIFACT ASSOCIATED WITH IMAGING A FETAL CRANIUM
Acoustic shadowing is an attenuation artifact, implying a change to the intensity of the ultrasound signal. Locational artifacts, by comparison, result in structures appearing displaced in the ultrasound image from the ‘true’ location, or indicating the appearance of a structure that is not ‘real’.
On many occasions, I have emphasized that artifacts are not necessarily ‘bad’. With a proper understanding of the underlying physics of how artifacts are generated, you can draw valuable insights from the existence of an artifact in an ultrasound study.
This subject matter is discussed more thoroughly in Chapter 8: Artifacts, of Frank Miele’s Ultrasound Physics and Instrumentation (5th edition). Acoustic shadowing and attenuation artifacts are referenced specifically on pages 275-276 and 284-285.
