1. From the Department of Radiology (H.K., S.G., C.B., M.A., R.K., W.B., D.F.K.), Mayo Clinic, Rochester, MN; College of Medicine (H.K.), Central Michigan University, Mount Pleasant; Department of Radiology (G.A.), Massachusetts General Hospital, Boston; Department of Neurology (H.T.), Medical College of Wisconsin, Milwaukee; Department of Neurologic Surgery (R.K.), Mayo Clinic, Rochester, MN; Department of Radiology and Neurosurgery (J.J.H.), Stanford University, CA; and Department of Neurology (A.A.R...