PMC7568101_01
Magnetic resonance image (MRI) of giant perivascular spaces (PVSs) (arrows). (a) Axial T2-weighted image (T2WI) at the level of midbrain. (b-e) Axial images at the level of thalamus. (b) T1WI, (c) T2WI, (d) postgadolinium T1WI, (e) fluid-attenuated inversion recovery image. (f) Coronal T2WI. (g) Sagittal T2WI.
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F1
MRI on June 2020 showed a cluster of cystic lesion, 28 mm in diameter as whole, in the left mesencephalothalamic region [Figure 1a]. T2-weighted MRI [Figure 1b-g]. There was no hyperintensity on FLAIR surrounding the lesion suggesting edema or gliosis. The similarity of MR intensity of cyst content to cerebral fluid on all MR sequences, lack of perilesional edema, and absence of gadolinium enhancement strongly suggested this lesion to be asymptomatic giant PVSs.
Enlarged PVSs in other locations.  : Part of the giant PVSs in the mesencephalothalamic region. (a) Right hippocampus (arrows). (b) Bilateral basal ganglia (boxes) and left hippocampus (arrow). (c) Bilateral basal ganglia (boxes) and left frontal operculum (arrowhead). (d) Subcortical white matter (circles).
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F2
Smaller PVSs were seen in other brain regions including bilateral-hippocampi, basal ganglia, white matter under convexity gray matter, and left frontal operculum [Figure 2a-d].
Chronological changes in the volume of the giant perivascular spaces. (a) September 2003: 6.54 ml. (b) May 2014: 8.05 ml. (c) February 2016: 8.19 ml. (d) July 2017: 8.79 ml. (e) June 2020: 9.83 ml. (f) 3D volumetric analysis showing steady and slow growth with gentle slope of linear function: y (ml) = 0.1752x+6.0012, R2=0.9072.
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F3
Retrospective review of the medical record and image archives found four previous MR studies on September 2003, May 2014, February 2016, and July 2017 [Figure 3a-e] in our and other hospitals due to chronic headache and uneasiness caused by suggestion of brain tumor by a previous attending. 3D volumetric analysis of the giant PVSs using Synapse Vincent software (Fuji film, Tokyo) showed a very slow enlargement, 6.54 ml in September 2003-9.83 ml in June 2020. It has grown with slope of linear function: y (ml) = 0.1752x+6.0012 (x: year-2000), R2 = 0.9072 [Figure 3f].
PMC7568101_02