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.

dx.doi.org/10.1136/jnnp-2014-308630, hdl.handle.net/1765/87664
Journal of Neurology, Neurosurgery and Psychiatry: an international peer-reviewed journal for health professionals and researchers in all areas of neurology and neurosurgery
Department of Neurology

Wattjes, M.P, Vennegoor, A, Steenwijk, M.D, de Vos, M, Killestein, J, Van Oosten, B.W, … Barkhof, F. (2015). MRI pattern in asymptomatic natalizumab-associated PML. Journal of Neurology, Neurosurgery and Psychiatry: an international peer-reviewed journal for health professionals and researchers in all areas of neurology and neurosurgery, 86(7), 793–798. doi:10.1136/jnnp-2014-308630