RIU 320 Lecture Notes - Lecture 71: Deep Structure And Surface Structure, Refraction, Comet Tail
21 Jun 2020
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Document Summary
In sonographic imaging, it is assumed that all reflections are received by the transducer before the next pulse is transmitted. Imagine that a reflection is created by a very deep structure and arrives at the transducer after the next pulse has been transmitted. This very deep reflection will be interpreted as being created by the second pulse and is therefore associated with a very shallow structure. Range ambiguity artifact occurs when a reflecting structure is located deeper than the imaging depth of the image. This reflector is placed at a shallow location on the image. Range ambiguity artifact is eliminated by increasing the pulse repetition period. Longer prp means deeper imaging and decreased prf. Appears as small amplitude echoes and results from many sources, including electrical interference, signal processing, and spurious reflections. Noise is more likely to affect low-level hypoechoic regions rather than bright echogenic areas.
