Beam width artifact
Ultrasound beam width artifact occurs when a reflective object located beyond the widened ultrasound beam, after the focal zone, creates false detectable echoes that are displayed as overlapping the structure of interest.
To understand this artifact, it is important to remember that the ultrasound beam is not uniform with depth, the main beam leaves the transducer with the same width as it, then narrows as it approaches the focal zone and widens again distal to this zone 1.
Usually, it occurs when scanning an anechoic structure and some peripheral echoes are identified, i.e. gas bubbles in the duodenum simulating small gallstones and peripheric echoes in the bladder.
It is possible to avoid this artifact adjusting the focal zone to the depth level of interest and by placing the transducer at the center of the object being studied.