1. Department of Radiology, New York Presbyterian Hospital-Weill Cornell Medical Center, 525 E 68th St, Box 141, New York, NY 10065.
2. Department of Anatomy in Radiology, Weill Cornell Medical College, New York, NY.
3. Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY.
4. Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY.