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
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
Anatomic classification of congenital limb deficiencies
The anatomic classification of congenital limb deficiencies is used to classify limb deficiencies.
The anatomic classification is proposed to systematically classify all congenital limb reduction defects and avoid terminology that can be considered imprecise or derogatory 1.
This system is cur...
Article
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...
Article
Aluminum
Aluminum (chemical symbol Al) is a trace metal and a nonessential element which is widely distributed throughout the Earth’s crust.
Chemistry
Physical chemistry
Aluminum is an element with the atomic number 13, one of the post-transition metals in the boron group (Group 13, IIIA) of the perio...
Article
Mean glandular dose
The mean glandular dose (MGD) is an estimate of the average absorbed dose to the glandular tissues of a breast during mammography. It is measured in Gray (Gy).
The most commonly accepted method of calculating the mean glandular dose is described by Dance et al (2000):
...
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 ...
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.
...
Article
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...
Article
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...
Article
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...
Article
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.
...
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...
Article
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...