Acoustic radiation force optical coherence elastography based on acousto-optic coupling for elasticity measurements

The elastic properties can be an indicator of pathological changes of biological tissue. Acoustic radiation force optical coherence elastography (ARF-OCE) allows remote, non-invasive assessment of the elastic properties of tissue. In this study, we proposed an acousto-optic coupling ARF-OCE method for the elasticity measurements. The acousto-optic coupling unit employs a rectangular prism with a close refractive index but significantly different acoustic impedance compared to water. Therefore, the surface of the rectangular prism immersed in water can reflect the ultrasound beam while transmitting the optical coherence tomography (OCT) detection beam. We demonstrated the acousto-optic coupling ARFOCE method using agar phantoms. The results show that the ARF-OCE method can induce elastic vibrations in the direction parallel to the OCT beam, resulting in higher detection sensitivity and a larger scanning range.