1. Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
2. Department of Diagnostic Radiology, Japanese Red Cross Kyoto Daiichi Hospital, Kyoto 605-0981, Japan.
3. Department of Radiology, Tokai University Hachioji Hospital, Tokai University School of Medicine, Tokyo 192-0032, Japan.