Trauma is a predominant cause of acute shoulder pain, commonly secondary to fractures (clavicle, scapula, or proximal humerus) or soft tissue injuries (typically involving the rotator cuff, acromioclavicular ligaments, or labroligamentous complex). Radiography is the imaging modality of choice for initial assessment of acute shoulder pain and identification of potential fractures. In cases where radiographs yield normal or inconclusive results, additional imaging modalities such as ultrasound, MRI, or CT of the shoulder without contrast, or MR or CT arthrography, may be useful to diagnose the underlying pathology. These modalities aid in the detection of conditions including nondisplaced fractures, tears of the labrum and rotator cuff, as well as detailed assessment of soft tissue and bony injury following glenohumeral joint dislocation. This document presents a comprehensive review of the evidence supporting or refuting the use of various imaging modalities in diagnosing acute shoulder pain. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.
