Case report: the "aurora sign"--a new sonographic sign of pneumatosis cystoides intestinalis.

Pneumatosis cystoides intestinalis (PCI) is a rare condition characterized by multiple gas-filled cysts of varying size within the intestinal wall. Although the characteristic findings on plain abdominal radiograph, computed tomography (CT), and barium enema have been well described, the sonographic findings have not. We recently encountered a case of PCI in which abdominal sonography disclosed a unique finding. We were able to reproduce the finding experimentally and have coined it the "aurora sign".