Fig 6.

Typical disease course of cPML in an HIV-positive patient receiving HAART. Top panel, a set of images at presentation with focal diffusion restriction (A and B) and very subtle but typical hypointensity on T1 (C) and hyperintensity on FLAIR (D). This initial study was confused with acute subcortical infarction. Middle panel, a set of images 1 month after the initial presentation. No HAART was administered before this scanning. Now the lesion has enlarged in size with typical diffusion restriction (arrows) at the medial and posterior advancing edges (E and F). Now the T1 hypointensity is more obvious (G). The adjacent cortex is not involved (arrows). Typically the lesion is hyperintense on FLAIR (H). Bottom panel, a set of images 19 months after initial presentation. The patient received HAART for 18 months. Now there is no diffusion restriction (I). On the T1-weighted sequence (J), there is profound T1 hypointensity associated with new/progressive atrophy. There is FLAIR hyperintensity in the adjacent areas. However, the main lesion is not hyperintense on FLAIR (K). On T2 (L), the lesion itself is very hyperintense compared with the adjacent white matter, suggesting cystic encephalomalacia. Note that the adjacent cortical architecture is preserved.