1. Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY 10065.
2. Department of Radiology, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain.
3. Lymphoma Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY.
4. Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY.