Reading from the ACR website, I saw the word "open" but not "free". At least in my experience it means no beer or speech. Remember that PACS systems use different file formats, storage technologies (flat file, RDMS, tree storage, etc.) and the ACR has interfaces to them all for peer review and other clinical processes. In this context it could just mean its building a toolkit that can operate on all systems.
According to this link: https://www.acrdsi.org/Get-Involved/AI-LAB more information will be released next month at their conference.