1. School of Engineering, Institute for Biology, Engineering and Medicine, Brown University, Providence, Rhode Island 02912, United States
2. Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, United States
3. School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
4. Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94143, United States