1. Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Box 3808, Durham, NC 27710.
2. Department of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
3. Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC.
4. Department of Radiology, University of Washington School of Medicine, Seattle, WA.
5. Department of Radiology, Cantonal Hospital, Lucerne, Switzerland.
6. Department of Radiology and Nuclear Medicine, Cantonal Hospital, Lucerne, Switzerland.