The library is aimed at developers of perfusion methods looking for specific functionality or development templates, or who want to share their own in-house developments with others. Task force 2.1 will define the structure of the library, licensing, naming conventions, documentation conventions, version control, code review, etc. . The library will include open-source functions, scripts and pipelines for perfusion imaging analysis. Contributions will be sourced from the community, and may include individual functions and more complete pipelines in various programming languages. OSIPI will organise these in a coherent and well-documented library structure, then identify and develop any missing functionality.