[1] Mayo Clin, Dept Radiol, Rochester, MN 55905 USA
[2] Mayo Clin, Dept Psychiat, Rochester, MN 55905 USA
[3] Gen Hosp Santa Chiara Trento, Dept Radiol, Trento, Italy
[4] Univ Utah, Dept Radiol, Neuroradiol Sect, Salt Lake City, UT 84132 USA
[5] Univ Utah, Dept Neurol, Salt Lake City, UT USA