Response to Letter Regarding Article, “Perfusion Characteristics of Moyamoya Disease: An Anatomically and Clinically Oriented Analysis and Comparison”

We thank Mugikura and Takahashi1 for their thoughtful analysis of our data on cerebral perfusion characteristics in Moyamoya disease (MMD).2 The authors present a detailed discussion of particular compensatory mechanisms provided by the posterior cerebral artery (PCA), namely a descriptive subcategorization into deep (proximal PCA to pericallosal artery) and more superficial collateralization (distal PCA to middle cerebral artery and anterior/posterior watershed). On the basis of our findings of relative preservation within the pericallosal territory, the authors hypothesize an insufficiency predominantly of superficial collateralization pathways. This particular territory may even be more at risk, if the …