Imaging Case of the Week 79

The following erect chest x-ray is from a 60 year old female who presented with a sudden onset of epigastric pain. The patient was also experiencing vague right-sided abdominal pain for a few days prior to the presentation. What can you note in the x-ray?

Erect chest x-ray

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[peekaboo_link name=”Answer”]Answer[/peekaboo_link] [peekaboo_content name=”Answer”]

The erect chest x-ray shows a subtle curvilinear lucency under the right hemi diaphragm, which is suggestive of free intraperitoneal air.


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The following sagittal CT scan image shows free subdiaphragmatic air.

sagittal ct

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pneumoperitoneum ct with retrocaecal appendicitis

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This patient had a retrocaecal appendicitis which perforated, causing pneumoperitoneum.

To allow the free air in the peritoneal cavity to rise, a patient needs to be upright for at least 10 minutes prior to obtaining the erect chest x-ray.