1. From the Department of Radiology (J.K., J.W., R.W.H.), University of Pennsylvania, Philadelphia; Department of Radiology (J.K.), Medical University of Gdansk, Poland; Medical University of Bialystok, Poland (A.U.); Department of Neurology, Ageing, Degenerative, and Cerebrovascular Diseases (M.A.), Silesian Medical University, Katowice, Poland; and Department of Neurology (S.E.K., B.L.C., S.R.M.), University of Pennsylvania, Philadelphia.