Suzuki and Takaku first described this staging system for moyamoya disease in their seminal 1969 article ¹. Formally, staging refers to findings from catheter angiography.

Usage

Although in wide use (c. 2023), the clinical utility of the Suzuki staging system has been questioned due to difficulties in delineating between stages and when used without serial evaluation ^6,7.

Classification

The Suzuki stages are as follows *:

• stage I

  • "narrowing of the carotid fork"

  • narrowed ICA bifurcation

• stage II

  • "initiation of the moyamoya"

  • dilated ACA, MCA and narrowed ICA bifurcation with moyamoya change

• stage III

  • "intensification of the moyamoya"

  • further increase in moyamoya change of the ICA bifurcation and narrowed ACA and MCA

• stage IV

  • "minimisation of the moyamoya"

  • moyamoya change reducing with occlusive changes in ICA and tenuous ACA and MCA

• stage V

  • "reduction of the moyamoya"

  • further decrease in moyamoya change with occlusion of ICA, ACA and MCA

• stage VI

  • "disappearance of the moyamoya"

  • ICA essentially disappeared with supply of brain from ECA

* the description in inverted commas (quotation marks) is that of Suzuki in the original paper

Interpretation

Suzuki stage appears to correlate with collateralisation in children, but not in adults ³.​ The vast majority of patients will progress through some or all of the Suzuki stages, although progression may occur at different rates ⁵, and appears to occur more rapidly in children than in adolescents or adults ⁴.