1. Medical Research Center Oulu, University of Oulu, P.O. Box 8000, Oulu, Finland
2. Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland
3. Department of Radiology, Turku University Hospital, P.O. Box 52, 20521 Turku, Finland
4. Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, 6th St SE, Minneapolis, MN 55455, USA
5. Department of Diagnostic Radiology, Oulu University Hospital, P.O. Box 50, 90029 Oulu, Finland