- Zhu, Yang;
- Deng, Kaicheng;
- Zhou, Jianwei;
- Lai, Chong;
- Ma, Zuwei;
- Zhang, Hua;
- Pan, Jiazhen;
- Shen, Liyin;
- Bucknor, Matthew;
- Kim, Seungil;
- Chen, Guangjie;
- Ye, Sang-Ho;
- Zhang, Yue;
- Liu, Donghong;
- Gao, Changyou;
- Xu, Yonghua;
- Wang, Huanan;
- Wagner, William;
- Ozhinsky, Eugene
Shape-memory materials hold great potential to impart medical devices with functionalities useful during implantation, locomotion, drug delivery, and removal. However, their clinical translation is limited by a lack of non-invasive and precise methods to trigger and control the shape recovery, especially for devices implanted in deep tissues. In this study, the application of image-guided high-intensity focused ultrasound (HIFU) heating is tested. Magnetic resonance-guided HIFU triggered shape-recovery of a device made of polyurethane urea while monitoring its temperature by magnetic resonance thermometry. Deformation of the polyurethane urea in a live canine bladder (5 cm deep) is achieved with 8 seconds of ultrasound-guided HIFU with millimeter resolution energy focus. Tissue sections show no hyperthermic tissue injury. A conceptual application in ureteral stent shape-recovery reduces removal resistance. In conclusion, image-guided HIFU demonstrates deep energy penetration, safety and speed.