Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA. pavel_pospisil@hms.harvard.edu|Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA. pavel_pospisil@hms.harvard.edu|Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA. pavel_pospisil@hms.harvard.edu|Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA. pavel_pospisil@hms.harvard.edu