1 Director of ED MRI and ED Radiology QA, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA. Electronic address: john.conklin@mgh.harvard.edu.
2 Director of Emergency Radiology and Emergency Neuroradiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA. Electronic address: mlev@partners.org.