Artifacts and Pitfalls in Contrast-Enhanced Ultrasound of the Liver

Abstract

Ultrasound technology is always connected to possible artefacts. Since introduction of ultrasound technology the knowledge of those artefacts is eminent to avoid misinterpretations. It is important to know that with the introduction of new ultrasound technology the possibility of artefacts are rising.Whereas artefacts initially were limited to B-mode sonography, every technological step (colour Doppler sonography, contrast enhanced sonography) comes with a range of new artefacts. This article is written to explain the technological basics of ultrasound artefacts and provide the reader with examples in daily practice and how to avoid them.

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“…Conventional, but imprecise time points separate these different phases (see also "contrast phases of enhancement") [40]. By convention, however, the timing of events on CEUS is routinely recorded by its actual time in seconds as shown on a visible timer on the scanner screen.…”

“…ver, a high frame rate is also important during sweeps of the liver to detect lesions so as to avoid skipping significant regions of the organ [40]. However, increased frame rates can augment bubble destruction, and decreasing the frame rate in the late vascular phases will prolong the enhancement time.…”

“…It is important to note that there is a direct linear relationship between P and the MI (within linear acoustics). Choosing the appropriate MI is important for effective CEUS because as summarized in [40] this parameter affects several processes relevant to image quality and microbubble behaviour. These parameters are listed below and discussed in more detail later.…”

“…Again, it is important to evaluate the status of the liver as being healthy or diseased. In difficult cases, a second (higher) dose may be administered, with no or only limited scanning in the early phases [40] to reduce bubble destruction. The exact dose depends on the UCA, ultrasound equipment (software version, transducer), type of examination, organ and target lesion, size and age of the patient and other factors.…”

“…The CEUS "circle of disaster" is characterized by the following criteria: Microbubble destruction → increase in contrast agent dose →attenuation (shadowing) → higher mechanical index → additional microbubble destruction [40,41,58].…”