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Ring artifact

Case contributed by Vikas Shah
Diagnosis certain

Presentation

40 year old man found collapsed. Persisting headache but no neurological signs.

Patient Data

Age: 40
Gender: Male

CT head

ct

There are no acute intracranial findings on this study. An artifact is seen, consisting of high density rings located in the same position on each slice. This is seen as a series of dots on the coronal reformatted image.

Case Discussion

This artifact is known as a ring artifact. It is caused by CT detector breakdown or malfunction, and a reboot of the machine usually solves the problem. In the days of film, this may have been confused for a mark left on the films by a cup of barium!

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