1. Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY 10065.
2. Department of Radiology, Hospital Sírio-Libanês, Sao Paulo, Brazil.
3. Department of Surgery, Colorectal Service, Memorial Sloan Kettering Cancer Center, New York, NY.
4. Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY.