MOYAMOYA-DISEASE IN THE UNITED-STATES

The epidemiology and radiological features of Moyamoya disease (MMD) i n the US were investigated. This study encompassed 98 cases; 26 were n ewly collected from eight US institutions and 72 were previously repor ted in the US literature. The patients ranged in age from 6 months to 67 years with age peaks in the first, third and fourth decades. MMD wa s seen in various ethnic groups and females were more commonly involve d (71%) than males. A specific etiology could not be determined in mos t cases but arteriosclerosis and use of oral contraceptives were occas ional associations. On angiography and/or magnetic resonance angiograp hy (MRA), carotid arterial stenosis or occlusion was seen bilaterally in 95 cases (97%) and unilaterally in three. On MR or MRA, internal ca rotid steno-occlusive lesions were well demonstrated in all cases but Moyamoya collateral vessels (MMVs) were visualized in only 65% of the patients. MMVs in the basal ganglia and thalami were best demonstrated on T1 weighted images. Parenchymal lesions were seen in all patients and were often bilateral. With advances in MR techniques and increasin g awareness of diagnostic guidelines, MMD will be diagnosed more frequ ently than before in the US. (C) 1997 Elsevier Science B.V.