Retrolenticular afterglow could occur through diffraction and refraction on interfaces. A circular object may act as a lens to the ultrasound beam, showing an artifact region of increased echogenicity.

Reverberation artifacts are produced from the multiple reflections from an object if the acoustical impedances of tissue layers are too much different and the detected echo does not run the shortest sound path because it bounces back and forth between the object and the transducer. In a reverberation artifact, the sound wave is reflected back into the body from the transducer-skin interface.

Radio frequency (RF) thermal ablation is a technique that uses the thermal effect created by radio frequencies to destroy tumors or metastases in the liver.
This treatment for liver cancer can accurately be evaluated by contrast enhanced ultrasound. RF thermal ablation monitored by sonography can lead to immediate re-treatment, preventing a second anesthesia and shortening the hospitalization time.

Ringing means the rise and decay time before and after the transducer reaches the maximum amplitude. Expressed as the mechanical Q of the transducer, which is the number of cycles it takes to get up to 90% of maximum amplitude or down to 10% above zero amplitude.

Different sound velocities in tissue are causing run-time artifacts.