Shear Wave Elasticity Imaging

Shear Wave Elasticity Imaging (SWEI) is a method of tissue elasticity assessment and visualization developed and patented by A. Sarvazyan, Chief Scientific Officer of Artann. In SWEI, the radiation force of focused ultrasound remotely induces localized shear waves, which are visualized by ultrasonic or MRI methods in order to assess tissue elasticity [1-6]. Since the terms “Elasticity Imaging” and "Elastography" are synonyms, the original term SWEI is often changed to SWE, which commonly stands for Shear Wave Elastography. Generally speaking, SWEI is a branch of both the Ultrasonic Elasticity Imaging (UEI) and Magnetic Resonance Elastography (MRE) - the rapidly maturing areas in the biomedical engineering [7,8]. UEI has already established a distinct niche among other methods of medical imaging and was successfully used to visualize various organs or lesions in organs including liver, prostate gland, breast, coronary arteries, etc. SWEI expands the fields of application of UEI as well as MRE by allowing characterization and imaging of such tissues as brain, which cannot be deformed or stressed by an outside vibrator.

In SWEI, radiation force exerted by a focused ultrasonic beam acts as a virtual finger remotely probing the elasticity of tissue. Analytical equations describing the spatial and temporal behavior of the radiation force induced shear waves in tissue-like media have been derived [9,10]. SWEI with MRI detection of the radiation force induced shear waves has been first realized in the NIH funded collaborative research project between Artann and the University of Michigan. SWEI with Doppler ultrasound detection of radiation force induced shear waves has been realized in another NIH funded research project conducted in Artann in collaboration with the University of Paris and Kharkov State University, Ukraine [11,12].

A license to SWEI and patents in this field is granted to Supersonic Imagine.

Publications and Patents
  1. Sarvazyan A, Hall TJ, Urban MW, Fatemi M, Aglyamov SR, Garra BS. An Overview of Elastography An Emerging Branch of Medical Imaging. Current Medical Imaging Reviews, 2011, 7(4):255-282.
  2. Sarvazyan AP, Urban MW, Greenleaf JF. Acoustic waves in medical imaging and diagnostics. Ultrasound Med Biol. 2013 39(7):1133-1146.
  3. Sarvazyan AP: Method and device for shear wave elasticity imaging. US Patent 5,606,971 1997.
  4. Sarvazyan AP, Rudenko OV: Method and apparatus for elasticity imaging using remotely induced shear wave. US Patent 5,810,731 1998.
  5. Sarvazyan AP, Rudenko OV, Swanson SD, Fowlkes JB, Emelianov SY: Shear wave elasticity imaging -- A new ultrasonic technology of medical diagnostics. Ultrasound Med Biol 1998; 24:1419-35.
  6. Sarvazyan AP, Skovoroda AR, Emelianov SY, Fowlkes JB, Pipe JG, Adler RS, Buxton RB, Carson PL:Biophysical bases of elasticity imaging. Acoustical Imaging 1995; 21(ed Jones JP, Plenum Press, New York and London), 223-40.
  7. Fowlkes JB, Emelianov SY, Pipe JG, Carson PL, Adler RS, Sarvazyan AP, Skovoroda AR: Possibility of cancer detection through measurement of elasticity properties. Radiology 1992; 185:123-4.
  8. Fowlkes JB, Emelianov SY, Pipe JG, Skovoroda AR, Adler RS, Carson PL, Sarvazyan AP: Magnetic resonance imaging techniques for detection of elasticity variation. Med Phys 1995; 22:1771-8.
  9. Rudenko OV, Sarvazyan AP, Emelianov SY: Acoustic radiation force and streaming induced by focused nonlinear ultrasound in a dissipative medium. J Acoust Soc Am 1996; 99:2791-98.
  10. Ostrovsky L, Sutin A, Ilinskii Y, Rudenko O, Sarvazyan A: Radiation force and shear motions in inhomogeneous media. J Acoust Soc Am 2007; 121(3):1324-31.
  11. Barannik EA, Girnyk A, Tovstiak V, Marusenko AI, Emelianov SY, Sarvazyan AP: Doppler ultrasound detection of shear waves remotely induced in tissue phantoms and tissue in vitro. Ultrasonics 2002; 40:849-52.
  12. Barannik EA, Girnyk A, Tovstiak V, Marusenko AI, Volokhov VA, Sarvazyan AP, Emelianov SY: The influence of viscosity on the shear strain remotely induced by focused ultrasound in viscoelastic media. J Acoust Soc Am 2004; 115(5):2358-64.