The greater the impedance difference between two structures, the greater the:

The relationship between impedance difference and reflection is rooted in the fundamental principles of ultrasound physics. Impedance is a measure of how much resistance a medium provides to the passage of ultrasound waves. When an ultrasound wave encounters the boundary between two different tissues, the degree of reflection that occurs at that boundary is directly influenced by the difference in their acoustic impedances.

A greater impedance difference between two structures leads to a more pronounced reflection of the ultrasound wave. This is because a significant disparity in impedance means that the wave encounters a substantial change in resistance, causing a larger portion of the wave to be reflected back into the original medium. Conversely, when the impedance of the two structures is similar, less of the wave is reflected, and more energy continues to pass through (i.e., is transmitted).

This principle is critical in sonography, as it helps in distinguishing between various tissues and organs based on the intensity and characteristics of the echoes received. Recognizing the role of impedance differences is essential for optimizing image quality and diagnostic accuracy in ultrasound imaging.