The Leptomeningeal “Ivy Sign” on Fluid-Attenuated Inversion Recovery MR Imaging in Moyamoya Disease: A Sign of Decreased Cerebral Vascular Reserve?

N Mori,T Murata,T Kaneta,M Fujimura,S Mugikura,S Takahashi,A Umetsu,S Higano

doi:10.3174/ajnr.a1504

Abstract

Moyamoya disease is an idiopathic occlusive cerebrovascular disorder with abnormal microvascular proliferation. We investigated the clinical utility of leptomeningeal high signal intensity (ivy sign) sometimes seen on fluid-attenuated inversion recovery images in Moyamoya disease. We examined the relationship between the degree of the ivy sign and the severity of the ischemic symptoms in 96 hemispheres of 48 patients with Moyamoya disease. We classified each cerebral hemisphere into 4 regions from anterior to posterior. In 192 regions of 24 patients, we examined the relationship between the degree of the ivy sign and findings of single-photon emission CT, including the resting cerebral blood flow (CBF) and cerebral vascular reserve (CVR). The degree of the ivy sign showed a significant positive relationship with the severity of the ischemic symptoms (P < .001). Of the 4 regions, the ivy sign was most frequently and prominently seen in the anterior part of the middle cerebral artery region. The degree of the ivy sign showed a negative relationship with the resting CBF (P < .0034) and a more prominent negative relationship with the CVR (P < .001). The leptomeningeal ivy sign indicates decreased CVR in Moyamoya disease.

Highlights

AND PURPOSE: Moyamoya disease is an idiopathic occlusive cerebrovascular disorder with abnormal microvascular proliferation
A recent study found that the ivy sign was more prominent in the hemispheres with poorer visualization of the cortical branches of the middle cerebral artery (MCA) on MR angiography.[3]
In our experience, a greater prominence of the ivy sign indicates more severe ischemic symptoms, which were found to decrease on follow-up MR images after effective revascularization surgery

Summary

Methods

We examined the relationship between the degree of the ivy sign and the severity of the ischemic symptoms in 96 hemispheres of 48 patients with Moyamoya disease. In 192 regions of 24 patients, we examined the relationship between the degree of the ivy sign and findings of singlephoton emission CT, including the resting cerebral blood flow (CBF) and cerebral vascular reserve (CVR). The remaining 48 patients with focal ischemic symptoms attributable to 1 cerebral hemisphere (14 males and 34 females ranging from 2 to 64 years of age, mean age 33 years) were included in this retrospective review. The FLAIR imaging was performed by using a fast inversion recovery sequence with TR, 9002 and 9002 ms; TEeff, 120 and 117 ms; TI, 2200 and 2100 ms; section thicknesses, 5.9 and 6.9 mm; section gap, 1.0 and 1.0 mm; matrix, 320 ϫ 224 and 320 ϫ 192 on the 1.5 and 1T scanners, respectively

Results

Discussion

Conclusion