1 Department of Radiology, University Medical Center, E.01.132, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. Electronic address: d.rutgers@umcutrecht.nl.
2 Department of Radiology, University Medical Center, E.01.132, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
3 Center for Image Sciences, University Medical Center, Utrecht, The Netherlands.
4 Center for Research and Development of Education, University Medical Center, Utrecht, The Netherlands.