A _____ is created when the sound beam bounces off one or more reflectors before it encounters a reflector that redirects it back to the transducer.

A _____ is created when the sound beam bounces off one or more reflectors before it encounters a reflector that redirects it back to the transducer.

• A. Multipath artifact
• B. Side lobe artifact
• C. Ring-down
• D. Acoustic shadow

Answer: (A)

Multipath artifact is being tested here. When the sound beam encounters one or more reflectors on its way back to the transducer, the path it travels isn’t the straight, single path assumed by the imaging system. That extra bouncing changes the travel time and the location from which echoes are interpreted, so the reflected signal may be displayed at an incorrect depth or as an unexpected additional feature. Other artifacts don’t involve this sequence of multiple reflections along the path: side lobe artifacts come from energy in off-axis lobes interfering with the main beam; ring-down results from resonating structures like gas bubbles; acoustic shadow shows up behind a highly attenuating object.

Multipath artifact is being tested here. When the sound beam encounters one or more reflectors on its way back to the transducer, the path it travels isn’t the straight, single path assumed by the imaging system. That extra bouncing changes the travel time and the location from which echoes are interpreted, so the reflected signal may be displayed at an incorrect depth or as an unexpected additional feature.

Other artifacts don’t involve this sequence of multiple reflections along the path: side lobe artifacts come from energy in off-axis lobes interfering with the main beam; ring-down results from resonating structures like gas bubbles; acoustic shadow shows up behind a highly attenuating object.