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We read with great interest the recent article by Drs Page & Gaillard describing neuroradiology signs and their variable utility .
We recently attempted to bring science to the art of descriptive radiological signs by conducting a randomized controlled trial to assess the utility of these signs for medical student radiology education . We found that ‘Metaphoric Signs’ (linking radiology resemblance to an object or concept which is not actually present in an image) increased descriptive and diagnostic ability as well as students’ lesson enjoyment, when compared to teaching with normal anatomy comparators.
The importance of diagnostic accuracy of commonly used signs was similarly emphasised in our discussion. In addition to being diagnostically accurate, the success of a metaphoric sign also relies on how well it resonates with each individual learner, based on their perception of the real-world similarity alluded to in the radiology image and their prior experiences[3,4]. This is aptly exemplified by Author FG’s stronger association of the pontine appearance in osmotic demyelination with a blockbuster sci-fi trilogy than classical mythology.
An interesting observation in our study was that several students used incorrect wording for the name of the signs yet identified the correct diagnosis. Students who correctly diagnosed agenesis of the corpus callosum from a coronal MRI image containing the ‘Moose head sign’  varia...
An interesting observation in our study was that several students used incorrect wording for the name of the signs yet identified the correct diagnosis. Students who correctly diagnosed agenesis of the corpus callosum from a coronal MRI image containing the ‘Moose head sign’  variably described a ‘Mule head’, ‘deer head’ and ‘antler head’ appearance. This may be explained by the wording of a sign having lesser importance for diagnosis than the strength of the metaphoric association identified by the learner between the radiological appearance and the real-world metaphoric resemblance, or ‘Pareidolia’.
Following on from this, we would suggest that the hoofed ruminant animal in Figure 2d of the paper by Page & Gaillard is actually stag deer (Subfamily: Cervinae, Genus: Cervus) rather than a Moose (Subfamily: Capreolinae, Genus: Alces). However, in our opinion, the coronal MRI provided (Figure 2c) appearance of agenesis of the corpus callosum truly does resemble a male deer (Stag) rather than a Moose! Therefore, the image provided may result in the strongest metaphoric association with the correct diagnosis in readers.
1. Page I, Gaillard F. Descriptive neuroradiology: beyond the hummingbird. Pract Neurol Published Online First: 27 August 2020. doi:10.1136/practneurol-2020-002526
2. Gibney B, Ghadir KH, Redmond CE et al. Pareidolia in Radiology Education: A Randomized Controlled Trial of Metaphoric Signs in Medical Student Teaching. Acad Radiol. 2020 Sep 17:S1076-6332(20)30498-0. doi: 10.1016/j.acra.2020.08.017.
3. Baker SR, Partyka L. Relative Importance of Metaphor in Radiology versus Other Medical Specialties. RadioGraphics. 2012;32:235–40. doi:10.1148/rg.321115721
4. Lakoff G. The contemporary theory of metaphor. Metaphor and Thought. 1993;:202–51. doi:10.1017/cbo9781139173865.013
5. Cherian EV, Shenoy KV, Bukelo MJ, et al. Racing car brings tear drops in the moose. BMJ Case Rep 2013;2013. doi:10.1136/bcr-2012-008165