1. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, MA 02134, USA.
2. Wyss Institute for Biologically Inspired Engineering, Boston, MA 20115, USA.
3. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
4. Division of Emergency Medicine, Boston Children’s Hospital, Boston, MA 02115, USA.
5. Department of Radiology, Boston Children’s Hospital, Boston, MA 02115, USA.
6. Departments of Pediatrics and Emergency Medicine, Harvard Medical School, Boston, MA 02115, USA.