[1] Univ Maryland, Sch Med, Baltimore, MD USA
[2] Univ Maryland, Sch Med, Dept Diagnost Radiol & Nucl Med, Baltimore, MD 21201 USA
[3] Univ Maryland, Sch Med, Dept Neurol, Baltimore, MD USA
[4] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD USA
[5] Univ Maryland, Sch Med, Dept Otorhinolaryngol Head & Neck Surg, Baltimore, MD 21201 USA
[6] Univ Maryland, Sch Med, Dept Pediat, Baltimore, MD 21201 USA
[7] Univ Maryland, Inst Hlth Comp, Bethesda, MD 20814 USA