Current consensus and guidelines of contrast enhanced ultrasound for the characterization of focal liver lesions

Abstract

The application of ultrasound contrast agents (UCAs) is considered essential when evaluating focal liver lesions (FLLs) using ultrasonography (US). Microbubble UCAs are easy to use and robust; their use poses no risk of nephrotoxicity and requires no ionizing radiation. The unique features of contrast enhanced US (CEUS) are not only noninvasiveness but also real-time assessing of liver perfusion throughout the vascular phases. The later feature has led to dramatic improvement in the diagnostic accuracy of US for detection and characterization of FLLs as well as the guidance to therapeutic procedures and evaluation of response to treatment. This article describes the current consensus and guidelines for the use of UCAs for the FLLs that are commonly encountered in US. After a brief description of the bases of different CEUS techniques, contrast-enhancement patterns of different types of benign and malignant FLLs and other clinical applications are described and discussed on the basis of our experience and the literature data.

Visualization of liver lesions in standardized video-documented ultrasonography – inter-observer agreement and effect of contrast injection

“…As for the inter-observer agreement, the radiologists were fairly consistent in their assessment, but no effect of contrast injection was found. It is often asserted that standardized and adequate training is needed to obtain optimal and reproducible results from ultrasound examinations, including CEUS [4]. For a complete examination, it is important with a detailed written protocol to establish the exact images that constitute a comprehensive examination [15].…”

“…Contrast-enhanced ultrasonography (CEUS) has improved both the detection and characterization of focal liver lesions and is a useful imaging method for distinguishing benign from malignant liver lesions [2,3]. There are three vascular phases, the late phase being the most important phase for distinguishing benign from malignant lesions, the hypovascularisation in this phase being the most specific signs of malignancy [4,5]. Previous studies have shown that CEUS is an accurate imaging method for the characterization of focal liver lesions and could be compared with contrast-CT and contrast MRI [6].…”

“…CEUS using a second-generation micro-bubble contrast agent poses no risk of nephrotoxicity and requires no radiation. It is possible to visually assess the liver perfusion throughout the vascular phases in real time [4].…”

Analysis of only 0-1 min clip or 1-4 min Clip for focal liver lesions during contrast-enhanced ultrasonography

“…Both readers were blinded to clinical features, laboratory examinations and other imaging findings. Then readers were asked to provide the most likely diagnosis (i.e., benign or malignant diagnosis, pathological diagnosis or indeterminate) for each focal liver lesion according to standard diagnostic criteria [3,4].…”

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