Korean J Radiol.  2017 Dec;18(6):992-1004. 10.3348/kjr.2017.18.6.992.

Signs in Neuroradiology: A Pictorial Review

• Kizilca O
• Öztek A
• Kesimal U
• Åženol U

• KMID: 2427209
• DOI: http://doi.org/10.3348/kjr.2017.18.6.992

Abstract

One of the major problems radiologists face in everyday practice is to decide the correct diagnosis, or at least narrow down the list of possibilities. In this context, indicative evidences (signs) are useful to recognize pathologies, and also to narrow the list of differential diagnoses. Despite classically being described for a single disease, or a closely related family of disorders, most indications are not restricted exclusively to their traditional definition. Therefore, using signs for prognosis requires knowledge of the mechanism of their appearance, and which pathologies they are observed in. In this study, we demonstrate some of the more common and useful neuroradiologic signs with relevant images, and discuss their use in differential diagnosis.

Keyword

Neuroradiology; Signs/indications; MRI; CT; Ultrasound; Brain

MeSH Terms

Brain/diagnostic imaging
Diagnosis, Differential
Humans
Magnetic Resonance Imaging
Nervous System Diseases/*diagnosis/diagnostic imaging
Tomography, X-Ray Computed
Ultrasonography

Figure

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  Fig. 1 Black hole sign. On this MRI T1WI, areas that are hypointense with respect to normal appearing white matter, are socalled “black holes” (arrow). T1WI = T1-weighted images

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  Fig. 2 Caput medusa sign. Coronal postcontrast MRI images demonstrate tubular converging towards common point in left cerebellar hemisphere (arrow). This appearance is characteristic of venous angiomas.

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  Fig. 3 Cloverleaf skull sign. Coronal CT image of infant with thanatophoric dysplasia shows trilobular cranium that looks like cloverleaf.

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  Fig. 4 Coca-Cola bottle sign. T1WI images of patient with Graves' ophthalmopathy demonstrates extraocular muscles having shape similar to Coca-Cola bottle (arrow), due to relative sparing of tendinous areas.

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  Fig. 5 Cord sign. Sagittal T1WI shows loss of flow void in cerebral vein, therefore appearing as hyperintensity (arrow).

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  Fig. 6 Cotton wool sign. Transverse CT image of patient with Paget's disease shows cotton wool appearance.

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  Fig. 7 Dawson fingers. Sagittal MRI FLAIR image of patient with MS shows hyperintensities perpendicular to corpus callosum (arrows), socalled Dawson fingers. FLAIR = fluid attenuated inversion recovery, MS = multiple sclerosis

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  Fig. 8 Dense MCA sign. On transverse CT image, left MCA appears hyperdense due to thrombus (arrow). MCA = middle cerebral artery

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  Fig. 9 Dural tail. Transverse MRI image shows dural “tail” of lesion (arrow), classically considered feature of meningiomas.

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  Fig. 10 Eye of tiger sign. Coronal T2WI shows eye of tiger sign (arrows) in patient with Hallervorden-Spatz syndrome. T2WI = T2weighted images

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  Fig. 11 Figure of 8. Coronal T1WI of MRI shows pituitary macroadenoma resembling figure of 8 (or snowman) (arrow) due to indentation at diaphragma sellae.

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  Fig. 12 Ground-glass appearance. Coronal CT image demonstrates ground-glass appearance in right temporal bone (arrow). Patient had diagnosis of fibrous dysplasia.

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  Fig. 13 Harlequin appearance. Head radiography shows uplifting of orbital roof with elevation of superolateral corner, so-called harlequin appearance.

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  Fig. 14 Horseshoe sign. In patient with MS, postcontrast MRI image demonstrates incomplete ring of enhancement, resembling horseshoe (arrow).

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  Fig. 15 Hot cross bun sign. T2WI shows cross shaped hyperintensity in pons (arrow). This patient had multiple system atrophy.

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  Fig. 16 Hot nose and empty skull. Tc99m-DTPA images show lack of activity inside cranium (“empty skull”) with increased activity in nasopharyngeal area due to increased flow via external carotid arteries (“hot nose”).

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  Fig. 17 Hummingbird sign. Mid-sagittal T1WI shows appearance similar to head and body of hummingbird (arrow), due to selective atrophy of tegmentum and relatively preserved pons.

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  Fig. 18 Ice cream cone sign. Coronal CT image shows normal appearance of incus and malleus, resembling ice cream cone (arrows).

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  Fig. 19 Ivy sign. Transverse FLAIR images of patient with moyamoya disease, showing sulcal hyperintensities that cover brain like ivy (arrows).

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  Fig. 20 Lemon sign. In patient with Chiari II malformation, transverse view of fetal head during prenatal ultrasonographic examination shows bifrontal flattening, causing head to look like lemon.

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  Fig. 21 Molar tooth sign. Transverse T1WI of MRI demonstrates appearance resembling molar tooth with horizontal tubular structure originating from midbrain on both sides of midline (arrows). This was patient with Joubert syndrome.

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  Fig. 22 Onion bulb sign. Coronal T1WI of patient with diagnosis of Balo's concentric sclerosis, shows concentric isointense and hypointense rings that look like onion bulb (arrow).

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  Fig. 23 Popcorn sign. Transverse T1WI demonstrates well-defined lobulated lesion with central area of heterogeneous signal intensities (arrow). This appearance is typical for cavernous hemangiomas.

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  Fig. 24 Puff of smoke. Lateral digital subtraction angiography image of patient with moyamoya disease shows characteristic appearance of network of tiny intracranial collateral vessels resembling “puff of smoke.”

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  Fig. 25 Pulvinar sign. Pulvinar hyperintensities (arrows) on FLAIR images of patient with Fabry disease.

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  Fig. 26 Swirl sign. Transverse CT image demonstrates hypoattenuating areas in otherwise hyperdense epidural hematoma (arrow), corresponding to active hemorrhage.

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  Fig. 27 Target sign. Postcontrast transverse MRI image reveals target-like lesions (arrow) in patient with cerebral metastases of malignant melanoma.

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  Fig. 28 Tiger stripe pattern. Transverse FLAIR image shows alternating hyperintense and hypointense bands in tiger stripe pattern, in right cerebellar hemisphere (arrow).

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  Fig. 29 Tigroid pattern. Transverse T2WI shows hypointense lines in otherwise hyperintese periventricular white matter (arrows), characteristically seen in metachromatic leukodystrophy.

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  Fig. 30 White cerebellum sign Transverse CT image of infant shows “white cerebellum” that appears denser than cerebral parenchyma (arrow). This appearance has very poor prognosis.

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