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By gaining a basic understanding of ultrasound physics and the common ultrasound artifacts, the nonradiologist veterinarian or veterinary sonographer can more clearly interpret the ultrasound image (Table 3.1). Always keep in mind the basic assumptions used to generate the image when scanning or viewing the ultrasound image. Your interpretive and diagnostic skills, and hence your patient, will benefit greatly.

 Knowing the basic assumptions used to generate the image leads to less misinterpretation of the ultrasound image.

 Artifacts are one of the primary pitfalls of ultrasonographic imaging.

Table 3.1. Summary of common artifacts and examples.

Name of artifact	Fluid‐associated	Air‐associated	Other	Common examples
Shadowing, clean	No	No	Bone/stone	Cystouroliths, ribs
Shadowing, dirty	No	Yes	Irregular/partial penetration into gas	Lung, stomach, colon, small intestine
Edge shadowing	No	No	Refraction off round structures	Stomach wall, gallbladder wall, urinary bladder wall
Acoustic enhancement	Yes	No	Decreased attenuation	Gallbladder, cysts, eye
Mirror image	No	Frequently	Reflection	Diaphragm/liverUrinary bladder/colon
Reverberation A‐lines	No	Yes	Typically used only in reference to lung ultrasound	Lung surface
Comet‐tail, ring‐down	No	No	Bone/stone/metal	Calculi, surgical clips, tissue mineralization
B‐lines, also called ultrasound lung rockets (ULRs)	Yes	Yes	Air–fluid interfaces	Lung
Pseudo B‐lines	Yes	Yes	Air–fluid interfaces (gastric luminal contents); strong soft tissue–air interfaces, i.e., lung nodules	Stomach contents, lung nodules
Side‐lobe	Yes	No	Multiple echoes	Urinary bladder lumen,gallbladder lumen
Slice‐thickness	Yes	No	Multiple echoes	False appearance of sludge in gallbladder, cysts