1. Department of Cardiology (S.M., T.Y.), Hokkaido Ohno Memorial Hospital, Sapporo, Japan.
2. Department of Radiology, Saitama Medical Center, Jichi Medical University, Saitama-shi, Japan (O.M.).
3. Department of Diagnostic Radiology (C.M.), Hokkaido Ohno Memorial Hospital, Sapporo, Japan.