1. The Radiology Department, The Royal Hospital , P.O. Box 1331, Ghala St, 111 Muscat , Oman
2. The National Heart Center, The Royal Hospital , P.O. Box 393, 18 November St, 100 Muscat , Oman
3. Centre of Studies and Research, Ministry of Health , P.O. Box 393, 100 Muscat , Oman