Fig. 2

MRI from a 53-year-old woman with PML. a T2-weighted sequence, axial section, shows poor definition and high SI in PML in the white matter of the right frontal lobe (white arrow). b T1-weighted sequence, axial section, shows poor definition and low SI in PML in the white matter of the right frontal lobe (white arrow). c 3D contrast-enhanced T1-weighted sequence, axial section, shows no enhancement in PML. d 3D ASL sequence, axial section, shows isointensity in PML. e APT scout image, axial section, shows the ROI placed in PML. f APT scout image, axial section, shows the ROI placed in normal-appearing tissue contralateral to lesion. g APT imaging shows low SI in PML (white arrow). PML progressive multifocal leukoencephalopathy, SI signal intensity, ASL arterial spin labelling, APT amide proton transfer