Hemicerebrum Infarction or Artifact: Effects of Out-of Center Positioning

CT scans are widely used for their ability to easily and rapidly obtain medical information. However, they are also vulnerable for artifacts. Fortunately, the majority is easily recognizable or is so well known that they are included in differential diagnosis on interpreting CT and rarely cause misdiagnosis or additional investigations.

We report 2 infants with rare CT hemicerebrum density differences. They were not consistent with the clinical condition of the patients and could be classified as being artifacts after MRI proved to be normal. Retrospectively, this could have been detected on CT by examining the eyes, which also showed not otherwise explicable density differences.

These artifacts appeared to be caused by out-of center positioning, as we could demonstrate with experimental phantom scanning. We have not found any previous reports on this type of artifact.

Recognition of this specific type of artifacts by observing similar density differences in the eyes does prevent unnecessary additional imaging.