Accepted for Publication: June 15, 2011.
Author Contributions:Study concept and design: Adachi and Yokoro. Acquisition of data: Adachi. Analysis and interpretation of data: Adachi. Drafting of the manuscript: Adachi. Critical revision of the manuscript for important intellectual content: Adachi and Yokoro. Administrative, technical, and material support: Adachi. Study supervision: Adachi and Yokoro.
Financial Disclosure: None reported.
Additional Contributions: Yukari Takada, MD, PhD, Department of Radiology, Tokyo Metropolitan Tama Medical Center, provided expertise in the radiographic analysis.