Elastography is any of a class of medical imaging diagnostic methods that map the elastic properties and stiffness of soft tissue.

[citation needed] Palpation is the practice of feeling the stiffness of a person's or animal's tissues with the health practitioner's hands.

Another limit of this technique is that like manual palpation, it has difficulty with organs or tissues that are not close to the surface or easily compressed.

[4] Acoustic radiation force impulse imaging (ARFI)[5] uses ultrasound to create a qualitative 2-D map of tissue stiffness.

Virtual Touch imaging quantification (VTIQ) has been successfully used to identify malignant cervical lymph nodes.

[6] In shear-wave elasticity imaging (SWEI),[7] similar to ARFI, a 'push' is induced deep in the tissue by acoustic radiation force.

By using an image modality like ultrasound or MRI to see how fast the wave gets to different lateral positions, the stiffness of the intervening tissue is inferred.

The principal difference between SWEI and ARFI is that SWEI is based on the use of shear waves propagating laterally from the beam axis and creating elasticity map by measuring shear wave propagation parameters whereas ARFI gets elasticity information from the axis of the pushing beam and uses multiple pushes to create a 2-D stiffness map.

Supersonic shear imaging (SSI)[8][9] gives a quantitative, real-time two-dimensional map of tissue stiffness.

First, by using many near-simultaneous pushes, SSI creates a source of shear waves which is moved through the medium at a supersonic speed.

SSI provides a set of quantitative and in vivo parameters describing the tissue mechanical properties: Young's modulus, viscosity, anisotropy.

[23][24] This technique is implemented in a device which can also assess the controlled attenuation parameter (CAP) which is good surrogate marker of liver steatosis.

An imaging acquisition sequence that measures the velocity of the waves is used, and this is used to infer the tissue's stiffness (the shear modulus).

MR elastography has made significant advances over the past few years with acquisition times down to a minute or less and has been used in a variety of medical applications including cardiology research on living human hearts.

[29] For OCE, a mechanical load is applied to the tissue and the resultant deformation is measured using speckle tracking or phase sensitive detection.

[30] Early implementations of OCE involved applying a quasi-static compression to the tissue,[31] though more recently dynamic loading has been achieved through the application of a sinusoidal modulation via a contact transducer or acoustic wave.

[32] The resultant deformation can be measured from the microscopy images using image-based nodal tracking algorithms,[32][33] and mechanical properties can be discerned using finite element method (FEM) analyses.

It can be used for additional diagnostic information compared to a mere anatomical image, and it can be used to guide biopsies or, increasingly, replace them entirely.

Elastography is particularly advantageous in this case because when fibrosis is diffuse (spread around in clumps rather than continuous scarring), a biopsy can easily miss sampling the diseased tissue, which results in a false negative misdiagnosis.

Certain types of elastography are also suitable for musculoskeletal imaging, and they can determine the mechanical properties and state of muscles and tendons.

In 2015, preliminary reports on elastography used on transplanted kidneys to evaluate cortical fibrosis have been published showing promising results.