Assessment of the difference in posterior circulation involvement between pediatric and adult patients with moyamoya disease

There is no description of the change in the posterior cerebral artery (PCA) in the diagnostic criteria of moyamoya disease (MMD). However, PCAs are often involved in the clinical setting, and an understanding of the significance of PCA lesions is therefore of great importance when evaluating the disease progression and predicting prognosis. The aim of this study was to assess the difference in posterior circulation involvement in pediatric and adult patients with MMD.The records of 120 consecutive patients with MMD were reviewed. The clinical manifestations at diagnosis were evaluated on the basis of symptoms and CT and MRI findings. The degree of steno-occlusive internal carotid artery (ICA) lesions and the existence of steno-occlusive PCA lesions were evaluated by observing a total of 240 ICAs and PCAs on angiography. Angiographic correlation between anterior and posterior circulation was assessed in pediatric and adult patients with MMD.Seventeen (26%) of 66 pediatric patients and 18 (33%) of 54 adult patients exhibited steno-occlusive PCA lesions. There was no significant difference in the prevalence of PCA lesions between pediatric and adult patients with MMD (p = 0.36). The prevalence of infarction in pediatric and adult patients with PCA involvement was significantly higher than that in pediatric and adult patients without PCA involvement (p = 0.0003 and p = 0.003, respectively). There was no significant difference in the distribution of infarction areas between pediatric and adult patients with PCA involvement (p = 0.62). On the basis of the staging system used, steno-occlusive lesions in ICAs ipsilateral to PCAs with lesions were in significantly advanced stages compared with lesions in ICAs ipsilateral to PCAs without lesions in both pediatric and adult cases (p < 0.0001 and p = 0.0008, respectively). Pediatric patients had less advanced steno-occlusive lesions in ICAs ipsilateral to PCAs with lesions compared with adults (p < 0.05).The clinical significance of posterior circulation involvement in MMD was similar between pediatric and adult patients. The only significant difference was that less advanced ICA lesions could complicate posterior circulation involvement in pediatric patients.