Correct eye shielding limits image artifacts during head CT exams

Shielding patients' eyes during CT examinations can lead to artifacts in the images, according to research published in the American Journal of Roentgenology. Correct positioning is necessary if providers wish to keep such artifacts to a minimum.

“The eye lens is an important organ and has to be protected as much as possible. Our study shows that the protectors have to be improved,” wrote lead author Stefan A. Schmidt, MD, of the University Hospital of Ulm in Germany, and colleagues. 

Without eye protection during CT exams, radiation exposure may increase the chances of cataracts. To mitigate this adverse outcome, eye protectors have been developed; however, this is a major disadvantage and leads to image artifacts.

Schmidt and colleagues sought to assess the frequency and extent of artifacts caused by protectors that are specifically related to the eye, brain and bone and their dependence on protector positioning. 

They obtained and assessed 261 consecutive head CT scans of patients who wore eye protection. The researchers determined the diagnostic quality of the images by objectively measuring and subjectively scoring on a Likert scale. The researchers also reviewed the position of the lens protector in connection to the eye lens and the intensity and frequency of artifacts.

Overall, 95 percent of the CT scans exhibited artifacts in the orbital cavity, while approximately 5 percent of images were completely free from artifacts. About 28 percent of all scans had brain artifacts and 2 percent had cranial bone artifacts, though only 6 percent of these artifacts risked misinterpretation.

Additionally, Schmidt et al. found that in 25 percent of cases, the lens was not properly covered by the protector. 

“Our data show that care should be taken when positioning the protector because misplaced protectors increased the frequency of artifacts,” the authors wrote. 

Further research regarding alternative protection is needed, the team noted.