All-Optical Ultrasound Enables Real-Time Tissue Imaging
Video-rate 2D imaging captures the dynamics of pulsating blood-vessel sections.
All-optical ultrasound is an emerging imaging technique in which ultrasound is generated and detected using optical components, which may overcome certain fundamental limitations of its electronic counterparts. Because the optical parts are insensitive to electromagnetic interference, it is suitable for real-time monitoring of radiofrequency ablation, electrophysiology and neuromodulation. Moreover, all-optical ultrasound can be used during MRI-guided interventional procedures, such as high-precision instrument localization, high-intensity focused ultrasound treatment, and microbubble-mediated drug delivery.
Although high-quality 2D and 3D all-optical ultrasound images of tissues have previously been presented, long acquisition times ranging from minutes to hours have hindered clinical application. In a study published in the August issue of Biomedical Optics Express, researchers describe an all-optical ultrasound imaging system capable of video-rate, real-time 2D imaging of biological tissue. This was achieved in part through the use of a highly efficient optical ultrasound generator and a highly sensitive fiber-optic receiver.
The system demonstrated a sustained frame rate of 15 hertz and a penetration depth of at least 6 millimeters, and captured the dynamics of pulsating blood-vessel sections. Moreover, the sensitivity of the system was suitable for imaging weak reflections from deep within biological tissue. According to the authors, this is the first demonstration of video-rate 2D all-optical ultrasound imaging of tissue.
“All-optical ultrasound imaging probes have the potential to revolutionize image-guided interventions,” said first author Erwin Alles of the University College London in the United Kingdom. “A lack of electronics and the resulting MRI compatibility will allow for true multimodality image guidance, with probes that are potentially just a fraction of the cost of conventional electronic counterparts.”