Multi-Frequency Coded ARFI Imaging of Porcine Eye Using Polarization-Inversion Piezocomposite Transducer

초록

For accurate diagnosis and management of anterior and posterior segment lesions, visualizing the elasticity of the entire eye is essential for comprehensive biomechanical assessment. Acoustic Radiation Force Impulse (ARFI) imaging provides a promising ultrasound-based approach, however, conventional pulse-based ARFI imaging suffers from low signal-to-noise ratio (SNR) and limited penetration, often requiring high input voltage, which may compromise safety in energy-sensitive ocular applications. In this study, we propose a whole-eye ARFI imaging technique that integrates multi-frequency coded excitation with a polarization-inversion piezocomposite transducer (PIPT), enabling whole-eye elastography at relatively low voltage. The PIPT, fabricated by stacking bulk and composite piezoelectric layers of identical thickness, simultaneously generates broadband fundamental (f0) and second-harmonic (2f0) components. Using chirp-based multi-frequency signal excitation, the mean displacement SNR in the far field increases by up to 12.2 dB compared with conventional pulse excitation. Furthermore, frequency compounding effectively combined complementary information from f0 and 2f0, yielding a more detailed representation of both anterior and posterior intraocular structures. Experimental validation with ex vivo porcine eye confirmed that the proposed method overcomes the limitation of conventional pulsed ARFI, achieving stable elastography across the entire eye. These results demonstrate that the proposed approach provides a promising pathway toward higher-resolution whole-eye ARFI imaging at increased operating frequencies under low-voltage operation. © 2013 IEEE.

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