[1] Univ Maryland, Sch Med, Dept Diagnost Radiol & Nucl Med, 670 West Baltimore St,Room L103, Baltimore, MD 21201 USA
[2] Univ Maryland, Sch Med, Ctr Adv Imaging Res CAIR, Baltimore, MD 21201 USA
[3] Univ Maryland, Sch Med, Dept Epidemiol & Publ Hlth, Baltimore, MD 21201 USA
[4] Univ Maryland, Sch Med, Neurol Program & Trauma, Dept Neurol, Baltimore, MD 21201 USA
[5] Walter Reed Natl Mil Med Ctr, Natl Intrepid Ctr Excellence, Bethesda, MD USA