Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.

16,834 results found
Article

Leber hereditary optic neuropathy

Leber hereditary optic neuropathy (LHON) is a mitochondrial genetic disorder characterized by bilateral, progressive, central vision loss secondary to loss of the retinal ganglionic cell layer 1,2. Epidemiology Leber hereditary optic neuropathy classically presents in young, Caucasian, adult m...
Article

Multinodular and vacuolating neuronal tumor

Multinodular and vacuolating neuronal tumors (MVNT) are lesions with distinct cytoarchitectural patterns. They are often considered part of the heterogeneous group of tumors known as long-term epilepsy-associated tumors (LEATs). Radiologically, MVNTs appear as small "bubbly" indolent subcortica...
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Pool sign (intracranial; metastatic adenocarcinoma)

The pool sign describes the brain MRI appearance whereby an intracranial mass exhibits a T2 hyperintense rim adjacent to a solid mass surrounded by peritumoral edema. This appearance has suggested to be a feature characteristic of metastatic adenocarcinoma (with various primaries). The "pool" p...
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Central vein sign

The central vein sign is a marker for multiple sclerosis (MS) and is the imaging manifestation of the perivenular nature of demyelinating plaques. It is not pathognomonic but can be useful in helping differentiate multiple sclerosis from mimics, such as cerebral small vessel disease, neuromyelit...
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Limb deficiency

Limb deficiencies or limb reduction defects are a spectrum of musculoskeletal disorders characterized by the absence or severe hypoplasia of a limb or part of a limb 1,2. Terminology Currently (c. 2024) the preferred terminology for limb deficiencies is based on the anatomic classification. Te...
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Demyelinating disorders

Demyelinating disorders are a subgroup of white matter disorders characterized by the destruction or damage of normally myelinated structures. These disorders may be inflammatory, infective, ischemic or toxic in origin and include 1-7: autoimmune demyelination multiple sclerosis (MS) Marburg ...
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Hepatomegaly

Hepatomegaly refers to an increase in size or enlargement of the liver.  Pathology Etiology Hepatomegaly can result from a vast range of pathology including, but not limited to, the following: malignancy/cellular infiltrate multiple metastases lymphoma(s) leukemia(s) hepatocellular carci...
Article

Neurobrucellosis

Neurobrucellosis refers to central nervous system involvement by brucellosis and occurs secondary to ingestion or contact with gram-negative, facultative intracellular coccobacilli of the Brucella species. Up to 10% of infections are complicated by neurological involvement 1.  The remainder of ...
Article

Describing recency

Describing when medical information was generated (e.g. new evidence, discoveries, etc.) is commonplace, and often essential, within articles. When providing these descriptions, the preference is to avoid use of 'recent', variations thereof (e.g. 'recently'), and synonyms thereof (e.g. 'new', '...
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Pulmonary hypertension

Pulmonary hypertension is currently defined as a resting mean pulmonary arterial pressure of >20 mmHg at right heart catheterization, which is a hemodynamic feature that is shared by all types of pulmonary hypertension. A resting mean pulmonary arterial pressure of ≤20 mmHg is considered normal...
Article

Lobar intracerebral hemorrhage

Lobar intracerebral hemorrhage is a subtype of intracerebral hemorrhage defined by their location in the peripheral cerebral hemispheres. Compared to deep intracerebral hemorrhages (involving the deep grey nuclei or brainstem), lobar hemorrhages are less likely to be related to hypertension and ...
Article

Cecal volvulus

Cecal volvulus describes torsion of the cecum around its mesentery which often results in obstruction. If unrecognised, it can result in bowel perforation and fecal peritonitis. Epidemiology Cecal volvulus accounts for ~10% of all intestinal volvuluses, and generally occur in somewhat younger ...
Article

Osmotic demyelination syndrome

Osmotic demyelination syndrome refers to acute demyelination seen in the setting of osmotic changes, typically with the rapid correction of hyponatremia. It is the preferred term replacing central pontine myelinolysis, recognizing that extrapontine structures can also be affected, previously kno...
Article

Hypothalamic hamartoma

Hypothalamic hamartomas, also known as tuber cinereum hamartomas, are benign non-neoplastic heterotopias in the brain that typically occur in the region of the hypothalamus, arising from the tuber cinereum, a part of the hypothalamus located between the mammillary bodies and the optic chiasm. E...
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Polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS), also known as hyperandrogenic anovulation, is a chronic anovulation syndrome associated with androgen excess.  The Rotterdam criteria is used to make the diagnosis of PCOS and require any two of the following three criteria for the diagnosis, as well as the e...
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Polycystic ovaries

Polycystic ovaries (PCO) or polycystic ovarian morphology (PCOM) is an imaging descriptor of a particular type of change in ovarian morphology. A proportion of women with polycystic ovaries will have the polycystic ovarian syndrome (PCOS), which in turn requires additional clinical, as well as b...
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Osteoporosis

Osteoporosis is a metabolic bone disease characterized by decreased bone mass and skeletal fragility. The World Health Organization (WHO) operationally defines osteoporosis as a bone mineral density T-score less than -2.5 SD (more than 2.5 standard deviations under the young-adult mean), which ...
Article

Sonic hedgehog-activated hepatocellular adenoma

Sonic hedgehog-activated hepatocellular adenomas (sh-HCA) are a subtype of hepatocellular adenomas. On imaging, it is still mostly diagnosed by exclusion of the other adenomas subtypes and other liver tumors. Epidemiology Most of sh-HCA were previously grouped under the unclassified adenomas,...
Article

Incidental thyroid nodule

Incidental thyroid nodules, sometimes called thyroid incidentalomas, are discrete lesions in the thyroid gland found on cross-sectional imaging performed for indications other than thyroid evaluation. They are common but occasionally represent thyroid cancer 1. This article discusses the epidemi...
Article

Brain metastases

Brain metastases are estimated to account for approximately 25-50% of intracranial tumors in hospitalized patients. Due to great variation in imaging appearances, these metastases present a common diagnostic challenge that can importantly affect the management approach for individual patients. ...

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