Refraction is the appearance of the sound wave being bent when the ultrasound beam obliquely crosses an interface with tissues with different densities and, thus, different propagation speeds. False or indirect reflection of the ultrasound wave.īy moving the transducer, the mirrored structure will disappear but the original structure will remain. Real or direct reflection of the ultrasound wave, 2. Mirrored structures can be found on the ultrasound image but not in the original structure. Ultrasound waves reflecting between structures can result in multiple reflections of the waves and mirroring of the structures between these layers. This can cause distortion of the Doppler waveform and make it difficult to accurately measure blood flow velocity. These artifacts can make it difficult to distinguish between small structures, such as blood vessels.ĭoppler artifacts occur when there is a high amount of motion in the area being imaged, such as blood flow. Speckle artifacts are caused by the interference of sound waves with each other, resulting in a granular or speckled appearance on the image. Structures with low acoustic impedance can artificially enhance the brightness below the structure, making it harder to visualize underlying structures (e.g., bladder, vessels). This can result in a hypoechoic or anechoic area on the image, making it difficult to visualize the underlying structure. This can cause a bright line to appear on the image, which can obscure underlying structures.Īttenuation artifacts occur when sound waves lose energy as they travel through tissue, causing a loss of signal intensity. Shadowing artifacts can also occur when sound waves encounter an area of decreased sound transmission.Įdge artifacts occur when sound waves encounter an abrupt change in tissue density, such as the boundary between two organs. Shadowing artifacts occur when sound waves are blocked by a dense object, such as a bone or gas-filled organ, causing a loss of signal and a shadow to appear on the image.
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