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Fig 1. Axial MR images of the brain in a case with multiple, prominent dilated perivascular spaces in left cerebral hemisphere.
A, Fluid-attenuated inversion-recovery (FLAIR) (TR/TEeff/TI, 6000/120/2000; echo-train length, 17) image shows multiple, well-defined, rounded hypointense foci of various sizes in the left cerebral hemisphere with signal intensity similar to that of CSF. Hyperintense areas adjacent to the hypointense foci are also observed in the left cerebral hemisphere. Two small dilated PVSs are seen in the right hemisphere.
B, FA map, obtained at a location similar to that in A shows decreased FA in the left cerebral white matter. This decreased FA is probably due to partial volume effect of dilated perivascular spaces.
C–E, FA maps at the levels of the corona radiata (C), posterior rim of the internal capsule (D), and cerebral peduncle (E). There was no alteration in the FA and ADC values for the corticospinal tracts of these areas, indicating no wallerian degeneration associated with dilated perivascular spaces. Circles indicate the region of interest we chose. The right and left FA values were 0.60 and 0.59 for the corona radiata, 0.62 and 0.64 for the posterior rim of the internal capsule, and 0.61 and 0.61 for the cerebral peduncle, respectively. The right and left ADC values (x 10–3mm2/s) were 0.76 and 0.76 for the corona radiata, 0.69 and 0.68 for the posterior rim of the internal capsule, and 0.73 and 0.72 for the cerebral peduncle, respectively.
F, Color-coded axial (upper) and coronal (lower) maps show preservation of the deep portion of the left corticospinal tract (arrows). The superficial portion of the left corticospinal tract is not demonstrated probably due to partial volume effect of dilated perivascular spaces.
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