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. Der technische Teil dieser Leitlinien und Empfehlungen, der unter der Federführung der EFSUMB entstanden ist, enthält eine Einleitung zu allen physikalischen Grundlagen und Methoden der aktuell kommerziell erhältlichen Ultraschall-Elastografie-Technologien. Unterschiede in der Schersteifigkeit sind der wesentliche physikalische Mechanismus, dem der Gewebekontrast in allen Elastogrammen zu Grunde liegt. Die Beziehung zu alternativen Technologien wird und die Vorteile der angewandten Methode herausgearbeitet. Die praktischen Vorteile und Nachteile jeder Technik werden beschrieben und Empfehlungen zur Optimierung der Scantechnik, der Bildqualität und der Bildinterpretation gegeben, ebenso werden einige der bekannten Artefakte dargestellt.

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. Der klinische Teil dieser unter der Schirmherrschaft der EFSUMB erstellten Richtlinien und Empfehlungen beurteilt die klinisch genutzten Anwendungen aller Formen der Elastografie, betont die Evidenz von Meta-Analysen und gibt praktische Hinweise in Bezug auf Einsatz und Interpretation der Elastografie. Die diffusen Lebererkrankungen nehmen den größten Teil ein und spiegeln somit die umfangreiche Erfahrung in der transienten und der ShearWave-Elastografie wider. Es folgen Brust, Schilddrüse, Gastrointestinaltrakt, endoskopische Elastografie, Prostata und Muskel-Skelett-System unter Verwendung von Strain und gegebenenfalls ShearWave-Elastografie. Diese Publikation soll als Empfehlung dienen und klinische Anwender auf praktische Art anleiten.

We present here the first update of the 2013 EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) Guidelines and Recommendations on the clinical use of elastography, focused on the assessment of diffuse liver disease. The first part (long version) of these Guidelines and Recommendations deals with the basic principles of elastography and provides an update of how the technology has changed. The practical advantages and disadvantages associated with each of the techniques are described, and guidance is provided regarding optimization of scanning technique, image display, image interpretation, reporting of data and some of the known image artefacts. The second part provides clinical information about the practical use of elastography equipment and the interpretation of results in the assessment of diffuse liver disease and analyzes the main findings based on published studies, stressing the evidence from meta-analyses. The role of elastography in different etiologies of liver disease and in several clinical scenarios is also discussed. All of the recommendations are judged with regard to their evidence-based strength according to the Oxford Centre for Evidence-Based Medicine Levels of Evidence. This updated document is intended to act as a reference and to provide a practical guide for both beginners and advanced clinical users.

This paper describes an inverse reconstruction technique based on a modified Newton Raphson iterative scheme and the finite element method, which has been developed for computing the spatial distribution of Young's modulus from within soft tissues. Computer simulations were conducted to determine the relative merits of reconstructing tissue elasticity using knowledge of (a) known displacement boundary conditions (DBC), and (b) known stress boundary conditions (SBC). The results demonstrated that computing Young's modulus using knowledge of SBC allows accurate quantification of Young's modulus. However, the quality of the images produced using this reconstruction approach was dependent on the Young's modulus distribution assumed at the start of the reconstruction procedure. Computing Young's modulus from known DBC provided relative estimates of tissue elasticity which, despite the disadvantage of not being able to accurately quantify Young's modulus, formed images that were generally superior in quality to those produced using the known SBC, and were not affected by the trial solution. The results of preliminary experiments on phantoms demonstrated that this reconstruction technique is capable in practice of improving the fidelity of tissue elasticity images, reducing the artefacts otherwise present in strain images, and recovering Young's modulus images that possess excellent spatial and contrast resolution.