[1] Univ Washington, Harborview Med Ctr, Dept Radiol, Seattle, WA 98104 USA
[2] Univ Washington, Harborview Med Ctr, Harborview Injury Prevent & Res Ctr, Seattle, WA 98104 USA
[3] Univ Vienna, Dept Radiol, A-1090 Vienna, Austria
[4] Univ Washington, Harborview Med Ctr, Dept Surg, Seattle, WA 98104 USA