Elastic wave imaging for elasticity measurements using handheld optical coherence elastography

Optical coherence tomography (OCT) enables high-resolution, label-free cross-sectional and volumetric imaging of biological tissues. Combining OCT imaging with external force excitation, optical coherence elastography (OCE) provides noninvasive elasticity quantification for the pathological analysis of tissues and early diagnosis of diseases. However, the OCE system with a fixed OCT sample arm cannot be used for elasticity measurements of tissues located in a narrow space, such as an oral cavity and an ear canal, because the OCT beam and external force cannot easily reach the tissues. In this study, we developed a handheld OCE method for the elasticity measurements based on elastic wave imaging. The handheld probe integrated an air pulse excitation unit and a microelectromechanical system-based scan imaging unit. The short air pulse induced the elastic wave in a sample. Then, the OCT data was captured by an M-B scan protocol, and the tissue vibration was analyzed by Doppler phase shifts. After elastic wave visualization, the elastic wave velocity was measured for the elasticity quantification. The results show that the handheld OCE method can quantify the elastic modulus with high flexibility for the tissue in a narrow, deep space.