Musculoskeletal Imaging

Pneumatocyst

a subchondral cyst containing gas. Pneumatocysts may occur in the ilium or sacroiliac joint in various diseases, including osteoarthritis and calcium pyrophosphate dihydrate crystal deposition disease. Rarely, these cysts occur in the spine, especially the cervical region. CT scanning is valuable diagnostically because gas present in soft tissue or bone has a very low attenuation.

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