1. Department of Computer Science, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada
2. Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
3. Nova Scotia Health Authority, Halifax, NS B3H 1V7, Canada
4. Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02215, USA