请教大家一个问题，本人在阅读关于乳腺癌新辅助化疗文献中出现”central revision“ ，内容如下：Pathologists in the study centers graded response and central revision on diagnostic slides was performed by an experienced pathologist (VS). If central revision was not possible because of absence of revision material, the response grade by study centers’ pathologists was used.

”central revision“ 怎么理解呢，能否麻烦专家帮我解答一下，谢谢您！