1. The Rheumatism Research Center, Catholic Research Institute of Medical Science, The Catholic University of Korea, Seoul 137-701, Korea.
2. Department of Internal Medicine, Bucheon St. Mary's Hospital, Bucheon 420-818, Korea.
3. Division of Rheumatology, Department of Internal Medicine, Kangnam Sacred Heart Hospital, Hallym University, Seoul 137-701, Korea.
4. Department of Radiology, Bucheon St. Mary's Hospital, Bucheon 420-818, Korea.