Isochoic wave is a term used in
ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
. Substances of a different medium are called isochoic if waves travel through them at the same speed.
Isochoic in ultrasound means that two structures have the same echogenicity in 2D mode (B-mode).
References
Basic Principles of Ultrasound Physics and Artifacts Made Easy
Ultrasound
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