PMC6152556_01
PMC6152556_02
PMC6152556_03
PMC6152556_04
Axial T2-weighted image of the brainstem shows symmetrical abnormal signal within posterolateral medulla oblongata and inferior cerebellar peduncles bilaterally as well as ill-defined, more diffuse high signal intensities in pons (arrows).
asm-1-64f1.jpg
PMC6152556_04_asm-1-64f1.jpg
f1-asm-1-64
The study included sagittal T1-weighted spin-echo, axial proton density and T2-weighted fast spin echo, axial fluid-attenuated inversion recovery (FLAIR), axial T1-weighted inversion recovery, and axial echo-planar diffusion-weighted (b: 0, 500, and 1000) imaging sequences. The long TR (T2-weighted FLAIR) images showed abnormal symmetrical high signal intensities within posterolateral medulla oblongata and inferior cerebellar peduncles as well as patchy hyperintensities within pons (Figure 1).
Axial FLAIR image showing symmetrical high signal intensity periventricular bands in both cerebral hemispheres (black arrows). A small subcortical white matter lesion is also noted (white arrow). Note incidental persistent cavum septi pellucidi.
asm-1-64f2.jpg
PMC6152556_04_asm-1-64f2.jpg
f2-asm-1-64
Additional subtle signal abnormalities were present supratentorially in frontal periventricular white matter bilaterally (Figure 2). A few scattered non-specific hyperintense foci were also noted within the cerebral hemispheric white matter on FLAIR images (Figure 2).
Axial echo-planar diffusion-weighted images of brainstem and cerebral hemispheres. No definite signal abnormalities are seen in lesion areas identified by conventional long TR images.
asm-1-64f3.jpg
PMC6152556_04_asm-1-64f3.jpg
f3-asm-1-64
The lesions were not associated with swelling or restricted water diffusion, suggesting a burned-out, early chronic state of the underlying histopathological processes (Figure 3).
Single-voxel proton MR spectroscopic findings. The spectrum with short echo time (STEAM, TE: 20 ms) demonstrates (from right to left) elevated levels of branched-chain amino acids and lipids (Baa/Lip), lactate (Lac), normal N-acetylaspartate (NAA), elevated glutamate and glutamine (Glu/Gln), normal creatine (Cr), choline (Cho), and myoinositol (mI) peaks (a). On long echo-time spectrum (PRESS, TE: 135 ms), the abnormal peaks all disappear (b).
asm-1-64f4.jpg
PMC6152556_04_asm-1-64f4.jpg
f4-asm-1-64
TE: 20 ms) showed a prominent positive peak doublet at the 1.3 to 1.4 ppm level (Figure 4a), which with a long echo-time (PRESS, TE: 135 ms) almost totally disappeared (Figure 4b). This was consistent with the elevated cerebral lactate.