The Study Of The Arterial Walls Of Moyamoya Disease By High-resolution Magnetic Resonance Imaging

Objective:By high-resolution magnetic resonance imaging(HR-MRI) to depict pathologicalarterial walls of middle cerebral artery (MCA),we explored the possible mechanismsof arterial progressive stenosis and remodel mode in moyamoya disease (MMD) andfurther elucidated differences in vessel wall changes compared to intracranialatherosclerotic disease.Methods:We studied21patients with MMD,13patients with atherosclerotic moyamoyasyndrome(AS-MMS) and44patients with atherosclerotic stenosis of middle cerebralartery(AS-MCA) from June2012to December2013in the neurology department ofthe second affiliated hospital of Nanchang University. Three-dimensionaltime-of-flight magnetic resonance angiography (3D TOF-MRA) and HR-MRI wereperformed on each patient.We analyzed the size of the outer diameter and wallthickness and other stenotic vessel wall characteristics of MCAs, including lumenmorphology,signal homogeneity and small and collateral vascular structures adjacentto stenosis position. In addition, the MCAs of MMD were divided into4groupsaccording to Houkin s MRA grades. We compared outer diameter and wall thicknessof the MCAs among different MRA grades.Results：(1) The age in the MMD group were39.00±9.68years, the AS-MMS groupwere49.31±8.50years and the AS-MCA group were61.57±7.74years. There werestatistically difference between any two groups (p <0.05).(2) The outer diameter（MMD,2.00±0.30mm vs. AS-MMS,2.54±0.46mm vs.AS-MCA,3.31±0.37mm）and wall thickness（MMD,0.39±0.19mm vs. AS-MMS,1.05±0.58mm vs. AS-MCA,1.64±0.38mm）were significantly smaller, along with concentric stenosis（MMD,91.4%vs. AS-MMS,44.4%vs. AS-MCA,36.9%）andwall singal homogeneous（MMD,85.7%vs. AS-MMS,27.8%vs. AS-MCA,32.6%）were significantly more in the MMD group than in the other two groups.(3) Compared with the AS-MCA group, the MMS-AS group were significantlymore small and collateral vascular structures（P<0.05）, but concentric stenosis andwall singal homogeneous were similar（P>0.05）.(4) Among all MCAs of MMD patients, MRA grade3was the most（42.86%）,followed were MRA grade2（31.43%）and MRA grade4（17.14%）,MRA grade1wasthe least（8.57%）.(5) In different MRA grade of MMD, the outer diameter were significantlydifference (p=0.006),but without wall thickness (p=0.077).Conclusion：(1) HR-MRI can study the pathological arterial walls of middle cerebral arteryin-vivo.(2) Arterial walls in MMD display smaller outer diameter and wall thickness,and have more concentric stenosis, homogeneous signal and small and collateralvascular structures compared with atherosclerotic disease. HR-MRI may have utilityin differentiating MMD from atherosclerotic disease.(3) Arterial stenosis in MMD may be a process of outside diameter reducing, andwithout the change of wall thickness. Arterial pathological vascular contraction mayparticipate process of progressive stenosis in moyamoya disease.(4) HR-MRI may provide information of arterial walls to the diagnosis ofatherosclerotic moyamoya syndrome.