PMC5491820_01
PMC5491820_02
Magnetic resonance imaging (MRI) at two time points in the clinical course. T1-weighted (A, F), gadolinium-enhanced T1-weighted (B, G), T2-weighted (C, H), diffusion-weighted (D, I), and fluid-attenuated inversion recovery (E, J) images are displayed. A set of MRI scans was performed after a one-month history of progressive visual disturbance (A-E), showing white matter lesions in the occipital lobe without gadolinium enhancement. Two months later, another set of MRI scans was performed (F-J), showing enlarged white matter lesions that included gray matter with cortical laminar necrosis and negative gadolinium enhancement.
1349-7235-56-1219-g001.jpg
PMC5491820_02_1349-7235-56-1219-g001.jpg
g001
T1-weighted images showed hypointensity (Fig. 1A-E). The results of gadolinium enhancement were negative. These MRI findings were typical of PML. The MRI findings at this time showed enlarged PML lesions that included the gray matter with cortical laminar necrosis and negative gadolinium enhancement (Fig. 1F-J).
A set of positron emission tomography (PET) images. Images for 18F-FDG (B), 11C-flumazenil (C), 11C-methionine (D), and 11C-4DST (E) superimposed on an MRI scan (A) are displayed in native space. The MRI scan (A) corresponds to Figure 1G and was used as an anatomical reference for the PET images. One month after conducting MRI (A), a set of PET scans was performed (B-E). Z maps, which are superimposed on a standard brain, represent the regions where the 18F-FDG (F) or 11C-flumazenil (G) uptake had decreased. The rainbow and red-yellow scales represent the magnitude of the standardized uptake values (B-E) and Z scores (F, G), respectively. MRI: magnetic resonance imaging, 18F-FDG: 18F-fluorodeoxyglucose, 11C-4DST: [methyl-11C] 4'-thiothymidine, R: right, L: left
1349-7235-56-1219-g002.jpg
PMC5491820_02_1349-7235-56-1219-g002.jpg
g002
Fig. 2. For 18F-FDG and 11C-flumazenil images, in order to determine the areas where the uptake of each radioligand decreased, statistical Z maps were created with the mean and standard deviation values from controls that belonged to a normal database at the institute (Fig. 2F and G). The uptake of 18F-FDG and 11C-flumazenil was found to have widely decreased in the occipital lobe and in the posterior part of the parietal lobe (Fig. 2B and C). The statistical Z maps showed that the magnitude of the decrease in the uptake of 18F-FDG and 11C-flumazenil on the left side was larger than that on the right side (Fig. 2F and G), consistent with the MRI findings. The 11C-methionine uptake tended to increase in the PML legions (Fig. 2D), whereas the 18F-FDG uptake tended to decrease and gadolinium enhancement was negative. No regions showed an increase in the 11C-4DST uptake (Fig. 2E).