1. From the Department of Neuroradiology (M.N.P., D.B., K.S., I.T., J.R.L., J.T., M.K.), Neurology (I.L.M., M.B., J.L.), and Medical Statistics (A.Z.), University Medical Center Göttingen, Germany; and Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (K.S.).