ARF-OCE for mapping mechanical properties of ocular and vascular tissues
July 23-26, 2017
Elastography is an imaging modality for clinical diagnosis based on the tissue stiffness. Benefiting from the high resolution, three-dimensional, and noninvasive nature of optical coherence tomography (OCT), optical coherence elastography (OCE) has the ability to determine elastic properties with a resolution of ~10 μm in 3D. Typical OCE imaging includes excitation for inducing mechanical vibrations, measurement of the sample response using OCT, and estimation of elastic parameters. Acoustic radiation force (ARF) generated by an ultrasonic transducer can noninvasively excite internal tissues without contact; thus, ARF-OCE is suitable for measuring the mechanical properties in deeper tissues. For assessment of the elastic properties of tissues using ARF-OCE, the shear wave velocity, resonant frequency, and vibrational displacement can be measured. Shear wave velocity measurements can be conveniently used for quantitative calculation of the elastic modulus.1-3 The resonant frequency of a tissue has a squared relationship with the Young's modulus, and thus can quantify the elasticity.4 Vibrational displacement can be compared directly when the same pressure is applied to different samples.5 Several diseases are accompanied by and result in the changes in composition and local geometry of tissues. Keratoconus, which causes vision distortions and blurriness, will change the geometry of the cornea. The development of presbyopia is generally caused by the loss of elasticity in the lens. The composition and biomechanical properties of vessels will usually be altered when atherosclerosis occurs. The ARF-OCE technology provides a new opportunity for the early diagnosis of ocular and vascular diseases. Based on the shear wave measurements, our system can be used to quantify the elastic modulus of the cornea and the crystalline lens. By comparing the vibrational displacement, we have detected the differences between normal and cross-linked cornea.6 Recently we developed a miniature probe for mapping the mechanical properties of vascular lesions using ARF-OCE. It has the ability to detect the a vulnerable plaque due to its higher stiffness.7 Because of the noninvasive nature, ARF-OCE has the potential to perform in vivo imaging of deep tissues for the early diagnosis of ocular and vascular diseases. 1. Zhu, J., Qu, Y., Ma, T., Li, R., Du, Y., Huang, S., Shung, K.K., Zhou, Q. and Chen, Z., 2015. Imaging and characterizing shear wave and shear modulus under orthogonal acoustic radiation force excitation using OCT Doppler variance method. Optics letters, 40(9): 2099-2102. 2. Zhu, J., Qi, L., Miao, Y., Ma, T., Dai, C., Qu, Y., He, Y., Gao, Y., Zhou, Q. and Chen, Z., 2016. 3D mapping of elastic modulus using shear wave optical micro-elastography. Scientific reports, 6: 35499. 3. Xu, X., Zhu, J. and Chen, Z., 2016. Dynamic and quantitative assessment of blood coagulation using optical coherence elastography. Scientific reports, 6: 24294. 4. Qi, W., Li, R., Ma, T., Li, J., Kirk Shung, K., Zhou, Q. and Chen, Z., 2013. Resonant acoustic radiation force optical coherence elastography. Applied physics letters, 103(10): 103704. 5. Qi, W., Li, R., Ma, T., Kirk Shung, K., Zhou, Q. and Chen, Z., 2014. Confocal acoustic radiation force optical coherence elastography using a ring ultrasonic transducer. Applied physics letters, 104(12): 123702. 6. Qu, Y., Ma, T., He, Y., Zhu, J., Dai, C., Yu, M., Huang, S., Lu, F., Shung, K.K., Zhou, Q. and Chen, Z., 2016. Acoustic radiation force optical coherence elastography of corneal tissue. IEEE Journal of Selected Topics in Quantum Electronics, 22(3): 288-294. Qu, Y., Ma, T., He, Y., Yu, M., Zhu, J., Miao, Y., Dai, C., Patel, P., Shung, K.K., Zhou, Q. and Chen, Z., 2017. Miniature probe for mapping mechanical properties of vascular lesions using acoustic radiation force optical coherence elastography. Scientific Reports, 7: 4731
Jiang Zhu; Youmin He,; Yueqiao Qu; and Zhongping Chen, "ARF-OCE for mapping mechanical properties of ocular and vascular tissues" in "Advances in Optics for Biotechnology, Medicine and Surgery XV", Peter So, Massachusetts Institute of Technology, USA Kate Bechtel, Triple Ring Technologies, USA Ivo Vellekoop, University of Twente, The Netherlands Michael Choma, Yale University, USA Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/biotech_med_xv/36
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