ARDMS Ultrasound Physics & Instrumentation Practice Exam

Areas of high pressure and density in ultrasound are known as what?

1. Cycles

2. Compressions

3. Rarefactions

4. Frequencies

The correct answer is: Compressions

In ultrasound, areas of high pressure and density within the sound wave are referred to as compressions. During the propagation of a sound wave, particles of the medium are compressed together in regions of high pressure, resulting in increased density. This compression is integral to how sound travels through different media. When a transducer emits an ultrasound pulse, it creates alternating areas of compression and rarefaction, where compression represents the regions of high pressure. Understanding this concept is essential for interpreting various ultrasound phenomena, including image formation and wave propagation behaviors. Compressions and their counterpart, rarefactions, are foundational to the nature of sound waves. They enable us to grasp how ultrasonic imaging works, as the machine detects the returning echoes from these pressure variations when the sound waves encounter different tissues within the body.