title: Shear wave elastography using amplitude-modulated acoustic radiation force and phase-sensitive optical coherence tomography.
abstract: Investigating the elasticity of ocular tissue (cornea and intraocular lens) could help the understanding and management of pathologies related to biomechanical deficiency. In previous studies, we introduced a setup based on optical coherence tomography for shear wave elastography (SWE) with high resolution and high sensitivity. SWE determines tissue stiffness from the propagation speed of shear waves launched within tissue. We proposed acoustic radiation force to remotely induce shear waves by focusing an ultrasound (US) beam in tissue, similar to several elastography techniques. Minimizing the maximum US pressure is essential in ophthalmology for safety reasons. For this purpose, we propose a pulse compression approach. It utilizes coded US emissions to generate shear waves where the energy is spread over a long emission, and then numerically compressed into a short, localized, and high-energy pulse. We used a 7.5-MHz single-element focused transducer driven by coded excitations where the amplitude is modulated by a linear frequency-swept square wave (1 to 7 kHz). An inverse filter approach was used for compression. We demonstrate the feasibility of performing shear wave elastography measurements in tissue-mimicking phantoms at low US pressures (mechanical index < 0.6)
authors.affiliation: University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P.O. Box 355013, Seattle, Washington 98105, United States.
authors.forename: Thu-Mai
authors.initials: TM
authors.lastname: Nguyen
authors.affiliation: University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P.O. Box 355013, Seattle, Washington 98105, United States.
authors.forename: Bastien
authors.initials: B
authors.lastname: Arnal
authors.affiliation: University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P.O. Box 355013, Seattle, Washington 98105, United StatesbUniversity of Dundee, School of Engineering, Departments of Physics and Mathematics, Fulton Building, Dundee DD1 4HN, Un.
authors.forename: Shaozhen
authors.initials: S
authors.lastname: Song
authors.affiliation: University of Dundee, School of Engineering, Departments of Physics and Mathematics, Fulton Building, Dundee DD1 4HN, United Kingdom.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Huang
authors.affiliation: University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P.O. Box 355013, Seattle, Washington 98105, United StatescUniversity of Washington, Department of Ophthalmology, 325 9th Avenue, Seattle, Washington 98104, United States.
authors.forename: Ruikang K
authors.initials: RK
authors.lastname: Wang
authors.affiliation: University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P.O. Box 355013, Seattle, Washington 98105, United States.
authors.forename: Matthew
authors.initials: M
authors.lastname: O'Donnell
mesh_terms: D000818:Animals; D003315:Cornea / Q000033:anatomy & histology; D054459:Elasticity Imaging Techniques / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio; D013552:Swine; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods*