Pareidolia in Radiology Education: A Randomized Controlled Trial of Metaphoric Signs in Medical Student Teaching

A radiology sign that references a resemblance to something which is not actually present within an image has been termed a 'metaphoric' sign. Metaphoric signs are widely described in the literature and commonly used in teaching as a form of pattern recognition, or 'pareidolia'. However, the educational benefit of metaphoric signs has not been previously assessed. We aimed to assess the utility of metaphoric signs in medical student teaching.

Fifteen radiology cases were prepared into two lecture formats for medical student education. A 'test' lecture utilizing metaphoric radiology signs to describe the appearance of the cases and a 'control' lecture where pathology was compared to normal anatomical appearances without reference to metaphoric signs. Forty-nine volunteer medical students were randomized with cluster sampling to receive either the test or control lecture. Four days later, students were quizzed to determine retention of knowledge and to assess interest in the lecture on a visual analogue scale from 0 to 100.

The median interest level of the test group (69.5) was higher than the control group (50) (p = 0.001). The mean quiz score was higher in the test group (34.5) than in the control group (29) (Difference 5.5, 95% confidence interval 0.08-10.92, p = 0.047).

The use of metaphoric signs in radiology education of medical students increased interest, descriptive ability and short-term knowledge retention, compared to the same material taught with normal anatomy correlation. Metaphoric signs should be considered as a useful radiology teaching tool.