A-453 17:00 C. Extremities U. Linsenmaier; Munich/DE (ulrich.linsenmaier@med.uni-muenchen.de) Extremity injuries in patients after polytrauma can be very complex and are often difficult to be diagnosed comprehensively when patients undergo only an initial whole body CT (WBCT). Extremity injuries comprise: fractures of (1) long bones, (2) articular joints, (3) complex fractures of hands and feet; (4) vascular, (5) soft tissue and (6) nerval and plexus injuries and (7) amputations. The use of MDCT could replace conventional radiographs (CR) in many indications. MDCT is indicated in all major and complex bony fractures and should be carried out early. Many institutions include those extremity scans in the WBCT workup using the arterial contrast phase as CT angiography (CTA) providing an excellent workup of the vascular system. CR remains an important diagnostic mean; however, these CRs should only be carried out after completion of the initial WBCT to avoid any dangerous delays in diagnosis of life-threatening injuries. CRs are especially suitable for follow-up and postoperative controls. Magnetic resonance imaging (MR) is an adjunct to MDCT and CR in the diagnosis of extremity injuries. It is indicated in complex injuries with unstable articular injuries, those involving tendons or major ligaments and nerval and plexus injuries. However, MR should only be carried out after complete stabilisation of the patient. Finally, it has to be mentioned that the operative treatment of extremity injuries must be priority oriented and carefully planned in the context of possible concomitant injuries and a possible risk of multi-organ failure (MOF). Sunday examples. Epidemiological, clinical and imaging findings of these diseases will be discussed, and differential diagnostic features will be proposed. It will also be discussed as to how these diseases insert into the broader general context of lung diseases, and how imaging can contribute to a better understanding of their respective clinical characteristics. Learning Objectives: