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

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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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 ...
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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...
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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...
Article

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.  ...
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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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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 ...
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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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Amyand hernia

Amyand hernias (alternative plural: herniae) are a rare form of inguinal hernia in which the vermiform appendix is located within the hernial sac. They are seen in less than 1% of inguinal hernias.  It should not be confused with an appendix-containing femoral hernia, known as a De Garengeot he...
Article

Esophageal web

Esophageal webs refer to an esophageal constriction caused by a thin mucosal membrane projecting into the lumen. Epidemiology Esophageal webs tend to affect middle-aged females. Clinical presentation Patients are usually asymptomatic and the finding may be incidental and unimportant. However...
Article

Medical abbreviations and acronyms (V)

This article contains a list of commonly used medical abbreviations and acronyms that start with the letter V and may be encountered in medicine and radiology (please keep the main list and any sublists in alphabetic order). A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R ...
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Renal trauma

Renal trauma can result from direct, blunt, penetrating, and iatrogenic injury. Epidemiology Renal injuries account for ~10% of abdominal trauma, and thus the demographic of affected individuals reflect that population. The incidence of renal injuries increases in pre-existing congenital or ac...
Article

West Point classification of humeral avulsion of the glenohumeral ligament

The West Point classification of humeral avulsion of the glenohumeral ligament (HAGL) was created to describe avulsion injuries of the inferior glenohumeral ligament (IGHL). Classification This classification has six types of lesions divided into two categories based on anterior or posterior i...

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