The technical part of these Guidelines and Recommendations, produced under the auspices of EFSUMB, provides an introduction to the physical principles and technology on which all forms of current commercially available ultrasound elastography are based. A difference in shear modulus is the common underlying physical mechanism that provides tissue contrast in all elastograms. The relationship between the alternative technologies is considered in terms of the method used to take advantage of this. The practical advantages and disadvantages associated with each of the techniques are described, and guidance is provided on optimisation of scanning technique, image display, image interpretation and some of the known image artefacts.

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The clinical part of these Guidelines and Recommendations produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology EFSUMB assesses the clinically used applications of all forms of elastography, stressing the evidence from meta-analyses and giving practical advice for their uses and interpretation. Diffuse liver disease forms the largest section, reflecting the wide experience with transient and shear wave elastography . Then follow the breast, thyroid, gastro-intestinal tract, endoscopic elastography, the prostate and the musculo-skeletal system using strain and shear wave elastography as appropriate. The document is intended to form a reference and to guide clinical users in a practical way.

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Ultrafast ultrasonic imaging is a rapidly developing field based on the unfocused transmission of plane or diverging ultrasound waves. This recent approach to ultrasound imaging leads to a large increase in raw ultrasound data available per acquisition. Bigger synchronous ultrasound imaging datasets can be exploited in order to strongly improve the discrimination between tissue and blood motion in the field of Doppler imaging. Here we propose a spatiotemporal singular value decomposition clutter rejection of ultrasonic data acquired at ultrafast frame rate. The singular value decomposition (SVD) takes benefits of the different features of tissue and blood motion in terms of spatiotemporal coherence and strongly outperforms conventional clutter rejection filters based on high pass temporal filtering. Whereas classical clutter filters operate on the temporal dimension only, SVD clutter filtering provides up to a four-dimensional approach (3D in space and 1D in time). We demonstrate the performance of SVD clutter filtering with a flow phantom study that showed an increased performance compared to other classical filters (better contrast to noise ratio with tissue motion between 1 and 10mm/s and axial blood flow as low as 2.6 mm/s). SVD clutter filtering revealed previously undetected blood flows such as microvascular networks or blood flows corrupted by significant tissue or probe motion artifacts. We report in vivo applications including small animal fUltrasound brain imaging (blood flow detection limit of 0.5 mm/s) and several clinical imaging cases, such as neonate brain imaging, liver or kidney Doppler imaging.

The concept of contrast imaging was introduced to ultrasound almost 30 years ago. The development of ultrasound contrast agents (USCAs), initially slowed by technical limitations, has become more dynamic during the past decade. The ideal USCA should be non-toxic, injectable intravenously, capable of crossing the pulmonary capillary bed after a peripheral injection, and stable enough to achieve enhancement for the duration of the examination. While satisfying cost-benefit requirements, it should provide not only Doppler but also gray-scale enhancement. Already, Doppler examinations are improved by using USCAs when studying deep and small vessels, vessels with low or slow flow, or vessels with a non-optimal insonation angle. Ultrasound contrast agents also enhance detection of flow within abnormal vessels, including tumor vascularization and stenotic vessels, and provide better delineation of ischemic areas. Research is focusing on the development of specific contrast imaging sequences that allow detection of tissue enhancement similar to that obtained with CT or MRI. These sequences take advantage of the nonlinear behavior of the microbubbles within the ultrasound field, bringing real-time perfusion imaging for liver, kidney, and the myocardium into reach. New objectives include targeted agents that could further widen USCA applications to specific delivery of active drugs such as anticoagulants or cytotoxic compounds. The combination of new generations of USCAs and new ultrasound image sequences appears to be very promising and currently represents a significant part of ultrasound research.

Dynamic Contrast Enhanced Ultrasound (DCE-US) is an imaging technique that utilizes microbubble contrast agents in diagnostic ultrasound. The EFSUMB guidelines published in 2004, updated in 2008 and 2011 focused on the use of DCE-US, including essential technical requirements, training, investigational procedures and steps, guidance on image interpretation, established and recommended clinical indications and safety considerations. However the quantification of images acquired with ultrasound contrast agents (UCAs) is not discussed in the guidelines. The purpose of this EFSUMB document is to provide some recommendations and descriptions of the quantification of ultrasound images, technical requirements for analysis of time-intensity curves (TICs), methodology for data analysis, and interpretation of the results.

“How to perform contrast-enhanced ultrasound (CEUS)” provides general advice on the use of ultrasound contrast agents (UCAs) for clinical decision-making and reviews technical parameters for optimal CEUS performance. CEUS techniques vary between centers, therefore, experts from EFSUMB, WFUMB and from the CEUS LI-RADS working group created a discussion forum to standardize the CEUS examination technique according to published evidence and best personal experience. The goal is to standardise the use and administration of UCAs to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients.