1From the Department of Diagnostic Radiology, Chonnam National University Hospital, Chonnam National University Medical School, 8 Hak-dong, Dong-Ku, Gwangju 501–757, South Korea. Presented as an education exhibit at the 2003 RSNA scientific assembly. Received March 4, 2004; revision requested April 7; received and accepted April 26. All authors have no financial relationships to disclose. Address correspondence to W.Y. (e-mail: [email protected]).