2D real-time imaging artifacts

anisotropy

occurs when the sound beam strikes a structure in a non-perpendicular manner, resulting in a loss of the true echogenicity of the structure

comet-tail

caused by several small, highly reflective interfaces

dirty shadowing

caused by air or bowel gas

edge shadowing

reflective or refractive effect seen deep to the margins of a round structure that has a significantly different speed of sound compared to surrounding tissue; may be termed refractive shadowing

mirror image

produced by a strong specular reflector and results in a copy of the anatomy being placed deeper than the correct location

(posterior) acoustic enhancement

produced when the sound beam is barely attenuated through a fluid or a fluid-filled structure; may occasionally be referred to as through transmission

refraction

caused by the bending of the ultrasound beam when it passes through an interface between two tissues with vastly dissimilar speeds of sound and the angle of the approach is not perpendicular

reverberation artifact

caused by a large acoustic interface and subsequent production of false echoes

ring-down artifact

artifact that appears as a solid streak or a chain of parallel bands radiating away from a structure

shadowing

• caused by attenuation of the sound beam

• can be seen posterior to bone, and calculi like gallstones and renal stones

side lobes

caused by sound beams that are peripheral to the main sound beam

slice thickness

caused by compression from 3D to 2D images