1. Department of Surgery, Western Hospital, Gordon St, Footscray, Victoria 3011, Australia
2. Department of Gastroenterology, Royal Melbourne Hospital, Grattan St, Parkville, Victoria 3011, Australia
3. Department of Radiology, Alfred Hospital, Commercial Rd, Prahran, Victoria 3181, Australia
4. School of Medicine, James Cook University, Townsville, Queensland 4814, Australia