Placement of an echo is determined by the reflectors round trip time and:

The placement of an echo is fundamentally linked to the round trip time of the sound wave, which is crucial for determining the depth at which a reflector is located in the tissue being examined. This round trip time essentially measures how long it takes for the ultrasound pulse to travel to the reflector and back to the transducer.

Propagation speed plays a pivotal role in this process. It is the speed at which the sound wave travels through a medium, which, in the case of ultrasound, is typically biological tissue. Each type of tissue has its own propagation speed due to variations in density and stiffness. However, the ultrasound machine requires knowledge of the propagation speed to calculate the distance to the reflector accurately using the time it took for the ultrasound pulse to return.

For example, if the propagation speed in soft tissue is approximately 1540 meters per second, the system uses this value in conjunction with the round trip time to determine how far away the structure is. This allows the formation of an accurate image based on the echo's placement.

While other factors like density and stiffness do affect how sound travels through various materials, they do not directly influence the calculation of echo placement in the context of ultrasound imaging as much as propagation speed does. Understanding the role of propagation speed is