title: MRI pattern in asymptomatic natalizumab-associated PML.
abstract: OBJECTIVE
  To investigate the MRI manifestation pattern of asymptomatic natalizumab-associated progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS).
  
  
  METHODS
  18 patients with MS with natalizumab-associated PML lesions on MRI were included. In 6 patients, the PML lesions were identified on MRI prospectively and in 12 patients PML lesions were identified retrospectively. MRI sequences were analysed for PML lesion distribution, appearance, grey matter/white matter involvement and possible signs of inflammation. Lesion probability maps were created to demonstrate lesion distribution pattern.
  
  
  RESULTS
  The frontal lobe was involved in 14 patients (77.8%) and the parietal lobe in 4 patients (22.2%). Most patients presented with focal lesions (13 patients, 72.2%) involving one single lobe (12 patients, 66.7%). The cortical grey matter was affected in 15 patients (83.3%) and 13 patients (72.2%) presented with a combination of cortical grey and white matter involvement. Signs of inflammation were detected in 7 patients (38.8%). Among patients with available diffusion-weighted imaging, 6 patients (40%) did not show high-signal-intensity lesions. A classical imaging pattern including unilateral and unilobar focal lesions in the frontal lobe affecting the cortical grey matter or the cortical grey and adjacent white matter was observed in 8 patients (44.4%).
  
  
  CONCLUSIONS
  Asymptomatic natalizumab-associated PML manifestations on MRI show a rather localised disease, frequently located in the frontal lobes, affecting the cortical grey matter and adjacent juxtacortical white matter. Awareness of this lesion pattern facilitates an earlier diagnosis of natalizumab-associated PML in an asymptomatic stage associated with a more favourable prognosis.
authors.affiliation: Department of Radiology and Nuclear Medicine, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Mike P
authors.initials: MP
authors.lastname: Wattjes
authors.affiliation: Department of Neurology, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Anke
authors.initials: A
authors.lastname: Vennegoor
authors.affiliation: Department of Radiology and Nuclear Medicine, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Martijn D
authors.initials: MD
authors.lastname: Steenwijk
authors.affiliation: Department of Radiology and Nuclear Medicine, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Marlieke
authors.initials: M
authors.lastname: de Vos
authors.affiliation: Department of Neurology, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Joep
authors.initials: J
authors.lastname: Killestein
authors.affiliation: Department of Neurology, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Bob W
authors.initials: BW
authors.lastname: van Oosten
authors.affiliation: Department of Neurology, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: Jop
authors.initials: J
authors.lastname: Mostert
authors.affiliation: Department of Neurology, Erasmus MC, University Medical Center Rotterdam, MS Center, Rotterdam, The Netherlands.
authors.forename: Dorine A
authors.initials: DA
authors.lastname: Siepman
authors.affiliation: Department of Neurology, Maasstad Hospital, Rotterdam, The Netherlands.
authors.forename: Wiebe
authors.initials: W
authors.lastname: Moll
authors.affiliation: Department of Neurology, GT Hospital Almelo, Almelo, The Netherlands.
authors.forename: Alex E L
authors.initials: AE
authors.lastname: van Golde
authors.affiliation: Department of Neurology, St. Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: Stephan T F M
authors.initials: ST
authors.lastname: Frequin
authors.affiliation: Multiple Sclerosis Clinical Development Group, Biogen Idec, Cambridge, Massachusetts, USA.
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Richert
authors.affiliation: Department of Radiology and Nuclear Medicine, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Frederik
authors.initials: F
authors.lastname: Barkhof
mesh_terms: D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects* / Q000627:therapeutic use; D058070:Asymptomatic Diseases; D001921:Brain / Q000187:drug effects / Q000473:pathology*; D005260:Female; D006801:Humans; D007968:Leukoencephalopathy, Progressive Multifocal / Q000139:chemically induced* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis; D000069442:Natalizumab; D059906:Neuroimaging
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000069442:Natalizumab
keywords: INFECTIOUS DISEASES; MRI; MULTIPLE SCLEROSIS; NEURORADIOLOGY