[1] HAMMERSMITH HOSP, MRC, CYCLOTRON UNIT, 150 DUCANE RD, LONDON W12 0HS, ENGLAND
[2] UNIV ROME LA SAPIENZA, DIPARTIMENTO SCI NEUROL, CATTEDRA NEUROPATOL & PSICOPATOL, I-00185 ROME, ITALY
[3] HOP PURPAN, SERV NEUROL, TOULOUSE, FRANCE
[4] HAMMERSMITH HOSP, DEPT RADIOL, LONDON W12 0HS, ENGLAND