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Crescent Sign
In radiology, the crescent sign is a finding on conventional radiographs that is associated with avascular necrosis. It usually occurs later in the disease, in stage III of the four-stage Ficat classification system. It appears as a curved epiphysis, subchondral radiodensity, radiolucent line that is often found on the proximal femur, femoral or humerus, humeral head. Usually, this sign indicates a high likelihood of collapse of the affected bone. The crescent sign may be best seen in an abducted (frog-legged) position. The crescent sign is caused by the necrosis, necrotic and repair processes that occur during avascular necrosis. Osteosclerosis occurs at a margin where new bone is placed over dead Cancellous bone, trabeculae. When the trabeculae experience stress leading to microfractures and collapse, the crescent sign appears. The crescent sign may be seen with other bone diseases, such as shear fractures. References {{Radiologic signs Musculoskeletal radiographic sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Crescent Sign
In radiology, the air crescent sign is a finding on chest radiograph and computed tomography that is crescenteric and radiodensity, radiolucent, due to a lung cavity that is filled with air and has a round radiodensity, radiopaque mass. Classically, it is due to an aspergilloma, a form of aspergillosis, that occurs when the fungus ''Aspergillus'' grows in a cavity in the lung. It is also referred as Monad sign. Additional images References External linksAir crescent sign on CXR Radiologic signs {{med-sign-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
