MANDUCA et Al. per year is increasing rapidly (Figure 1). However, numerous types of acquisitions and processing techniques are in use, and MRE results have been expressed in many different quantities: shear modulus (possibly complex), storage modulus, magnitude of the complex shear modulus, shear stiffness (defined in different ways), wave speed, propagation, loss modulus, attenuation, loss tangent or loss factor, phase angle, damping ratio, attenuation, and penetration rate. This list is not exhaustive and does not include additional quantities related to fitting specific assumed material models or anisotropic materials. This diversity of terminology and absence of standardization can lead to confusion (particularly among clinicians) as to the meaning of certain terms, or how to interpret or compare certain types of MRE results. This paper is written by the MRE Guidelines Committee, a group formalized at the first meeting of the ISMRM MRE Study Group, to attempt to clarify and (to some extent) standardize MRE terminology and practice. Specifically, the purpose of this paper is to (1) explain MRE terminology to those not familiar with it, (2) define "good practices" for practitioners of MRE, and (3) discuss some practices and terms that we believe should be standardized and some that should be discouraged. F I G U R E 2 Schematic stress-strain relationship for soft tissue unloaded and at three different tissue-loading states. Magnetic resonance elastography measures the slope of this curve at a given point, as indicated by the tangent line at ε 3