The 50 most fascinating neuroradiological pareidolias

Humans have a tendency to see patterns and images where none exist. Many of these patterns were created (or evolved, depending on your view) as early warning systems against the many predators that plot our early demise as they lurk in dark and sinister shadows.

By Diego Delso, CC BY-SA 4.0, Link

The commonest image the brain imagines is the face. The brains of social media users require very little prompting to conjure up a smiley or a frownie (if that is the word for it). All it takes is a comma and a colon (:. It also doesn’t require much prompting for the brain to create faces out of the most mundane objects as in the image below:

By Aleph79Own work, CC BY-SA 3.0, Link

Neurology, perhaps more than any other field of medicine, has made the best use of this self-deception. This phenomenon that enables us to see non-existent faces and objects comes under the umbrella term of pareidolias. There are many very useful clinical pareidolias in neurology, for example the classical inverted champagne bottle appearance which describes the shape of the leg in Charcot Marie Tooth disease (CMT). The most intriguing patterns are however seen on brain imaging, and  Neurochecklists is keeping account of these countless neuroradiological pareidolias under three intriguing checklists:

Classic neuroradiological signs

Miscellaneous neuroradiological signs

Neuroradiological signs in stroke


Here then is our list of the 50 most fascinating neuroradiological pareidolias.


Banana sign

Bare/empty orbit sign

Bright tongue sign

Boxcar ventricle sign

Butterfly sign

Champagne bottle neck sign

Chasing the dragon sign

By David Revoy / Blender FoundationOwn work, CC BY 3.0, Link

Corpus callosum splenium sign

Dense middle cerebral artery sign

Double panda sign

Double rim sign

Dural tail  sign

Ears of the lynx sign

Profile of the lynx. Tambako the Jaguar on Flikr.

Elephant sign

Empty delta sign

Eye of the tiger sign

Face of the giant panda sign

Smithsonian’s National Zoo’s Giant Panda Turns Four! Smithsonian’s National Zoo on Flikr.

Figure of eight sign

Haemosiderin cap sign

Harlequin eye sign

Hockey stick sign

Hot cross bun sign

Hummingbird sign

By Joseph C BooneOwn work, CC BY-SA 4.0, Link

Hypodense artery sign

Infundibulum sign

Ivy sign

Lemon sign

Lentiform fork sign

Leopard skin sign

Medusa head sign

By Miguel Hermoso CuestaOwn work, CC BY-SA 4.0, Link

Middle cerebellar peduncle (MCP) sign

Molar tooth sign

Omega/trident sign

Puff of smoke sign

Pulvinar sign

Punched-out corpus callosum sign

Radial band sign

Salt and pepper sign

Scalpel sign

Snake eyes sign

Snake eyes. Thomas Hawk on Flikr.

Spot sign

Spring sign

Starfield sign

Starry sky/swiss cheese sign

Swallow tail sign

Swirl sign

Tigroid sign

Tram track sign

Wine glass sign

Zebra sign

By ClipartqueenOwn work, CC0, Link


Why not explore more neuroradiology pearls in our other 35 neuroradiology checklists such as:

Basal ganglia calcification

Bilateral thalamic lesions

Cerebellopontine angle (CP angle) lesions

Cortical abnormalities

Corticospinal tract hyperintensity

Enhancing meningeal lesions

Headache imaging pathologies


MRI T1 high signal lesions

Radiation necrosis v tumour recurrence

Reversible splenial lesions

Sellar and parasellar lesions

Third ventricle lesions

White matter lesions

By Thomas Schultz – Own work, CC BY-SA 3.0, Link

To explore these and many other comprehensive neurology checklists…

Go online at


Or get the book, 700 Essential Neurology Checklists

2 thoughts on “The 50 most fascinating neuroradiological pareidolias

  1. Fantastic collection and grouping of intriguing signs in Neuroradiology! Thank you!Prof. Capt. B. Biswakumar.

    Sent from Yahoo Mail for iPhone


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