Leptomeningeal high signal intensity (ivy sign) on fluid-attenuated inversion-recovery (FLAIR) MR images in moyamoya disease

Leptomeningeal high signal intensity (ivy sign) on FLAIR images is predominantly seen in the frontal and parietal lobes. Because this sign can be seen in patients with unremarkable moyamoya vessels, LMHI is a useful sign in conventional MR imaging for the diagnosis of moyamoya disease.