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

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 ...
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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,...
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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...
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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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CSF-venous fistula

CSF-venous fistulas are an underdiagnosed cause of spontaneous intracranial hypotension. They are direct communication between the spinal subarachnoid space and epidural veins allowing for the loss of CSF directly into the circulation and can be either iatrogenic or spontaneous in etiology.  Ep...
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Coronary stent

Coronary stents or coronary artery stents are expandable tubular medical meshwork devices used for interventional treatment of coronary artery disease and prevention of negative remodeling and vascular recoil, restenosis as well as abrupt vessel occlusion from local coronary artery dissection af...
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Periprocedural anticoagulation

Periprocedural anticoagulation planning is essential when planning an interventional procedure so that the best balance between the risk of bleeding and thrombosis can be achieved. The following must be considered in assessment of periprocedural anticoagulation: bleeding risks associated with ...
Article

Lymphatic system

The lymphatic system (also known as the lymphoid system or systema lymphoideum in Terminologia Anatomica) is the collective term given to the lymphatic vessels and lymphoid tissues in the body 1,4. Terminology Occasionally the lymphatic system is considered with the reticuloendothelial system ...
Article

Nigrosomes

Nigrosomes are small clusters of dopaminergic cells within the substantia nigra that exhibit calbindin D28K negativity on immunohistochemistry. Five nigrosomes measuring up to a few millimeters in size have been described with the largest labeled as nigrosome-1 1. Nigrosome-1 Nigrosome-1 withi...
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White coat hypertension

White coat hypertension (WCH or WCHT), and not to be confused with the white coat effect (WCE), is commonly defined as typical in-clinic blood pressure (BP) measurements of 140/90 mm Hg or more in the presence of multiple daytime out-of-clinic home or ambulatory BP readings averaging less than 1...
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Alzheimer disease

Alzheimer disease is a common neurodegenerative disease, responsible for 60-80% of all dementias, and imposing a significant burden on developed nations. It is associated with an accumulation and deposition of cerebral amyloid-β (Aβ) and is the most common cerebral amyloid deposition disease.  ...
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...
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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...
Article

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 ...
Article

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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