1. Department of Neurology, University of Iowa Carver College of Medicine, Iowa City (D.Q.-O., C.Z., M.F., A.M.-R., S.O.-G.).
2. Siemens Healthcare, Imaging and Therapy Systems, Forchheim, Germany (S.S.).
3. Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA (G.A.).
4. Department of Neurology, Yale University School of Medicine, New Haven, CT (N.P.).