aMike O'Callaghan Federal Medical Center, Nellis Air Force Base, NV
bDepartment of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA
cDepartment of Orthopedic Surgery, University of California San Francisco, San Francisco, CA
dVeterans Affairs Medical Center, San Francisco, CA
Financial Disclosure: The authors report no conflicts of interest.
Correspondence to Akash P. Kansagra, MD, 505 Parnassus Avenue, M-391, San Francisco, CA 94143-0628 Tel: +415 476 1537; fax: +415 476 0616; e-mail: firstname.lastname@example.org