Articles

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16,906 results found
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Alexander disease

Alexander disease, also known as fibrinoid leukodystrophy, is a rare fatal leukodystrophy. Usually clinically evident in the infantile period, neonatal, juvenile, and adult variants are recognized. As with many diseases with a variable age of presentation, the earlier it manifests the more fulmi...
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External auditory canal cholesteatoma

External auditory canal cholesteatomas are a rare subtype of acquired cholesteatoma. Epidemiology The external acoustic canal is a rare location for a cholesteatoma with an estimated incidence of around 1.2 per 1,000 new otological patients ref. The overall incidence rate in one large study wa...
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Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common gastrointestinal condition in premature neonates. It is characterized by inflammation, ischemia, and permeability of the neonatal bowel wall to bacteria. It is potentially life-threatening with significant associated morbidity 1. Epidemiology ...
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Multiplanar reformation (MPR)

Multiplanar reformation or reconstruction (MPR) involves the process of converting data from an imaging modality acquired in a certain plane, usually axial, into another plane 1. It is most commonly performed with thin-slice data from volumetric CT in the axial plane, but it may be accomplished ...
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Periosteal osteosarcoma

Periosteal osteosarcomas are intermediate-grade bone-forming neoplasms originating on the bony surface in strong association, typically underneath the periosteum. Epidemiology Periosteal osteosarcomas are the second most common type of surface-based osteosarcoma after parosteal osteosarcoma an...
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Parotid gland tumors

Parotid gland tumors include a variety of benign and malignant entities that are also found in other salivary glands (see salivary gland tumors). The frequency of different tumors varies considerably among the salivary glands with the parotid gland hosting the majority of all salivary gland tumo...
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Animal and animal produce inspired signs

Animal and animal produce inspired signs may sound a little silly, but the radiology literature is replete with such signs, some more fanciful than others. Fish and marine life cluster of black pearls sign endosteal scalloping: medullary cavity masses, e.g. multiple myeloma fish vertebra (al...
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Chipmunk sign (brainstem)

The chipmunk sign refers to the MRI appearance of the medulla in some patients with leukodystrophies, particularly Alexander disease. The same appearance has been described in adult polyglucosan body disease, vanishing white matter disease, Pelizaeus-Merzbacher disease, 4H syndrome, and adult-on...
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Idiopathic orbital inflammation

Idiopathic orbital inflammation, also known as orbital pseudotumor, or idiopathic orbital inflammatory syndrome and non-specific orbital inflammation, is an idiopathic inflammatory condition that most commonly involves the extraocular muscles. Less commonly there is inflammatory change involving...
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Autoimmune glial fibrillary acid protein (GFAP) astrocytopathy

Autoimmune glial fibrillary acid protein (GFAP) astrocytopathy, or simply GFAP astrocytopathy, is a rare inflammatory central nervous system (CNS) disorder. Epidemiology Given the rarity of the condition, epidemiological data pertaining to autoimmune GFAP astrocytopathy are not well establishe...
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Iterative reconstruction (CT)

Iterative reconstruction refers to an image reconstruction algorithm used in CT that begins with an image assumption and compares it to real-time measured values while making constant adjustments until the two are in agreement. Computer technology limited early scanners in their ability to perf...
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Active surveillance

Active surveillance describes a management option aiming at close monitoring of a specific stage of disease and minimizing adverse treatment-related effects without compromising survival at the same time. Curative or definite treatment is intended and offered upon deterioration or explicit patie...
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Double skull sign (cephalohematoma)

The double skull sign is an eggshell calcification seen on CT in early cases of calcified cephalohematomas.
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Optic neuritis

Optic neuritis denotes inflammation of the optic nerve and is one of the more common causes of optic neuropathy. It can be thought of as broadly divided into infectious and non-infectious causes, although the latter is far more frequent (including idiopathic cases). On imaging, optic neuritis is...
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Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD)

Myelin oligodendrocyte glycoprotein​ antibody-associated disease (MOGAD) represents a group of inflammatory demyelinating disorders united by the presence of IgG antibodies to myelin oligodendrocyte glycoprotein (MOG). MOGAD represents a distinct clinical entity that clinically overlaps but is n...
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Optic perineuritis

Optic perineuritis, also known as perioptic neuritis, refers to inflammation of the optic nerve sheath. Optic perineuritis may manifest on its own, or together with inflammation of adjacent ocular or orbital structures. Epidemiology Optic perineuritis is likely rare 1, but the exact incidence ...
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Lingual thyroid

A lingual thyroid is a specific type of ectopic thyroid and results from the lack of normal caudal migration of the thyroid gland. NB: Location at the base of the tongue aside, the information in this article can relate to any ectopic thyroid tissue. Epidemiology The condition is congenital a...
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Thyroglossal duct cyst

Thyroglossal duct cysts are the most common type of congenital neck cysts and pediatric neck masses. They are typically located in the midline and are the most common midline neck mass in young patients. They can be diagnosed with multiple imaging modalities including ultrasound, CT and MRI. Ep...
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Area postrema syndrome

Area postrema syndrome is a disorder of the chemoreceptor trigger zone (area postrema) which is located on the medial posteroinferior surface of the medulla oblongata. It is usually a demyelinating disorder, as one of the core clinical characteristics of neuromyelitis optica spectrum disorder 1,...
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Neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a severe demyelinating diseases, which in seropositive cases, is caused by an autoantibody to the aquaporin-4 (AQP4) water channel. The classic presentation of NMOSD is with the triad of optic neuritis, longitudinally extensive myelitis, and posi...

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