1. From the Departments of Medicine (Dr. Ahmed), Biomedical Statistics (Dr. Greer), Radiology (Dr. Bakheet), Surgery (Drs. Abdulkareem, Ingemansson) and Pathology (Drs. Akhtar, Ali), King Faisal Specialist Hospital and Research Centre; Department of Medicine (Dr. Al-Nuaim), King Saud University, Riyadh, and Dammam Central Hospital (Dr. Al Saihati), Dammam