Objective and Impact Statement: Simultaneous imaging of ultrasound and optical contrasts can help map structural, functional and molecular biomarkers inside living subjects with high spatial resolution. There is a need to develop a platform to facilitate this multimodal imaging capability to improve diagnostic sensitivity and specificity. Introduction: Currently, combining ultrasound, photoacoustic and optical imaging modalities is challenging due to complex arrangements, in order to co-align both optical and ultrasound waves within the same field of view, because conventional ultrasound transducer arrays are optically opaque. Methods: One elegant solution is to make the ultrasound transducer transparent to light. Here, we demonstrate a novel transparent ultrasound transducer (TUT) liner array fabricated using a transparent lithium niobate piezoelectric material for real-time multimodal imaging. Results: The TUT array consisted of 64 elements and centered at ~6 MHz frequency. We demonstrate a quad-mode ultrasound, Doppler ultrasound, photoacoustic and fluorescence imaging in real-time using the TUT array directly coupled to the tissue mimicking phantoms. Conclusion: The TUT array successfully showed a multimodal imaging capability, and has potential applications in diagnosing cancer, neuro and vascular diseases, including image-guided endoscopy and wearable imaging.
Recent Developments in Vascular Imaging Techniques in Tissue Engineering and Regenerative Medicine