Intravascular ultrasound (IVUS) imaging is a powerful tool for cardiovascular diagnosis and treatment guidance, and if often used as an adjunct to several cardiovascular procedures. IVUS can reduce potential complications for procedures such as stent deployment, and has been investigated as a diagnostic tool for vulnerable plaque identification. Accumulated clinical experience, however, has revealed two major limitations of these devices. First, image resolution is not adequate to detect the early stages of certain arterial pathologies. Such limited resolution masks early stages of atherosclerosis, especially thin fibrous plaque development. In addition, image contrast cannot consistently identify lipid pools within plaques. Very high frequency ultrasound imaging in the range from 30 to 100 MHz can resolve structures almost down to the cellular level. Developing such an imaging modality for clinical use could have tremendous impact on diagnostic and therapeutic procedures in many clinical areas. For example, interventional cardiologists would be able to visualize in greater detail the arterial walls using advanced IVUS systems. Cancer diagnosis for oncologists could be revolutionized as in-situ microscopy could replace the traditional biopsy. Image-guided therapy systems could leverage these devices since pathology is localized at great precision.
Researchers at the University of Michigan have developed a novel optical technique for ultrasound detection and generation. It uses optical microresonators of very high quality factor acting as highly sensitive ultrasound receivers. Preliminary measurements using resonators of moderate quality factors have shown extraordinarily high sensitivity. These results imply that a resonator having a greater quality factor could deliver even higher sensitivity and provide image resolution at least five times better than that of existing ultrasound scanners.
Applications and Advantages
- Image-guided therapies
- Functional and pharmacological-nl-testing in vitro.
- Increased image resolution over existing-nl-scanners
- Small and can be manufactured at low cost
- Ideal for disposable systems and for-nl-incorporation into existing interventional-nl-devices