Standards Development

Scope

This International Standard is applicable to medical-diagnostic, ultrasonic shear-wave elastography systems exciting (internally or externally) shear waves and tracking the propagation of these shear waves within liver tissue.

 This International Standard establishes:

- requirements for defining particular types of test objects

- the preparation and validation of test objects

The previous Part 1 specifies quantities and parameters which must be provided to the user of shear-wave elastography systems. A future Part 3 will define test parameters and procedures to determine performance and constancy of shear-wave elastography systems. Note :The first edition of the standard focuses on liver applications of shear -wave elastography but
does not exclude its application to other organs (e. g. breast, thyroid, prostate, kidney).

Purpose

Elastography Imaging (EI) in general and shear-wave elastography (imaging) in particular has become a State-of-the-Art measurement and a quantitative-imaging modality. The relevant measurand is the speed of the shear waves travelling within the tissue unde r investigation, which is related to its elasticity. Although ultrasound elastography is already used in clinical diagnosis, no IEC standard describing the relevant metrological tools, the traceable characterisation of elastography phantoms and methods for EI system testing and quality assurance exists.

Justification

 The determined shear-wave speeds (and thus the derived elastic moduli) depend on many technical, operator- and patient-related factors, such as the device and method of use, the measurement depth, the size and shape of the region of interest (ROI), the bre athing phase, patient position, body-mass index (BMI), diet and blood pressure and also the operator's experience. To underpin and further establish shear-wave elastography as a well-understood, accurate and reproducible, quantitative-imaging modality, the metrological assessment of the method is necessary. The proposed multipart standard allows comparison of elastography images over time, across patients and different types of equipment, leading to advances in the sensitivity and specificity of clinical diagnosis, improving patient care and ensuring efficient use of resources.