American College of Radiology Releases New and Updated ACR Appropriateness Criteria ACR releases 13 new topics and five revised topics to support referring physicians and other providers in making the most appropriate imaging or treatment decisions April 26, 2021 — The American College of Radiology (ACR) released an update to its ACR Appropriateness Criteria (ACR AC), which includes 211 diagnostic imaging and interventional radiology topics with more than 1,000 clinical variants covering approximately 1,900 clinical scenarios. This update includes 13 new and five revised topics. All topics include a narrative, evidence table and a literature search summary. Patient-friendly summaries, a tool to help patients understand what tests are appropriate for their situation and enhance communication from ordering physicians and radiologists, are available for numerous topics.