Echocardiography Techniques II Exam 1 Practice 2026 – All-in-One Resource to Master Your Exam!

Doppler effect describes the change in frequency of a wave caused by relative motion between the source and observer. When the source and observer move toward each other, the observed frequency increases; when they move apart, it decreases. In ultrasound, moving blood cells or cardiac tissue create a shifted frequency in the received signal, and the amount of shift relates to the velocity along the line of sight. This shift is often described by a Doppler equation and is the principle behind measuring flow and tissue motion in echocardiography. Bernoulli's principle speaks to pressure-velocity relationships in fluids, tissue Doppler is a specific Doppler application to heart tissue, and refraction is the bending of waves at interfaces—not the frequency change due to motion.