Purpose: Adult patients with moyamoya disease present with ischemic symptoms or intracranial hemorrhages. Our purpose is to determine the angiographical differences between the two.
Methods and Materials: Eighty-six adult-onset patients were eligible, including those with focal ischemic symptoms or with intracranial hemorrhages on CT scans in which referable side were determined or those without symptoms. We classified all hemispheres into one of three types: hemispheres with ischemic symptoms (ischemic type) (n=51), those with intracranial hemorrhage (hemorrhagic type) (n=41) and those without symptoms (asymptomatic type) (n=80). We reviewed angiograms for the severity of stenoocclusive involvement in the internal carotid artery (ICAs), that in the posterior cerebral artery (PCAs). We also reviewed for the degree of development of transdural collateral circulations mainly from the external carotid artery and ophthalmic artery (transdural collaterals) in 78 patients. In all patients, CT scans or MR imaging or both were reviewed for the prevalence of infarctions. We examined the difference in angiographic and CT/MR findings between three types of hemispheres.
Results: ICA stages in the ischemic or hemorrhagic type hemispheres were significantly more advanced than asymptomatic type hemispheres(P value by Bonferroni correction, P<0.05 and P<0.05, respectively), however there was no significant difference in ICA stages between in ischemic and hemorrhagic types. PCA stages in the ischemic type was significantly more advanced than in the hemorrhagic type or in asymptomatic hemispheres(P<0.05 and P<0.05, respectively). Transdural collaterals in the ischemic type were more significantly developed than in the hemorrhagic type or in asymptomatic hemispheres(P<0.05 and P<0.05, respectively).The prevalence of infarctions in the ischemic type was significantly higher than in the hemorrhagic type or in asymptomatic hemispheres (P<0.01 and P<0.01, respectively).
Conclusion: Patients with less advanced PCA stages tend to present with intracranial hemorrhages. While patients with the more advanced PCA stages tend to present with ischemic symptoms with infarctions. Transdural collaterals are well developed in patients with ischemic symptoms, but they may not be sufficient to compensate for reduced leptomeningeal collaterals from often affected PCA.