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.
319 results found
Article
Gadolinium
Gadolinium (chemical symbol Gd) is a metallic element that can be chelated into paramagnetic complexes for use as gadolinium contrast media.
Chemistry
Basic chemistry
Gadolinium is a silvery rare earth metal, and a member of the lanthanides, with the atomic number 64 and an atomic weight of 1...
Article
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a thin, slightly curved bacillus. A member of the Mycobacterium tuberculosis complex, it is an obligate aerobic bacterium that is the etiologic agent of the majority of tuberculosis cases.
Epidemiology
The worldwide incidence of tuberculosis was 8.7 million in 20...
Article
Oxygen
Oxygen (chemical symbol O) is one of the basic organic elements, and is a constituent of most of the known organic molecules - and therefore all lifeforms - on earth.
Chemistry
Basic chemistry
Oxygen is a colourless odorless diatomic gas with an atomic number 8 and atomic weight 15.999. It h...
Article
Nitrogen
Nitrogen (chemical symbol N) is one of the basic organic elements and is a key constituent of amino acids, the building blocks of proteins, and of nucleic acids (i.e. DNA and RNA). On earth it is the most abundant element found in its pure form and comprises 78% of all breathable air.
Chemistr...
Article
Tungsten
Tungsten (chemical symbol, W) is a hard refractory metallic element with remarkable resilience which forms the basis for its industrial uses. It is the metal of choice in the filaments and targets of x-ray tubes. There is no evidence that tungsten is required by the human body, although some mic...
Article
Lipohyalinosis
Lipohyalinosis (also known as fibrinoid necrosis) is a disease affecting the small cerebral arteries associated with lacunar infarction and deep white matter changes related to small vessel chronic ischemia.
Pathology
The histopathological landmarks of lipohyalinosis are irregular fibrosis and...
Article
Atresia
Atresia (plural: atresias) refers to a situation where there is absence, underdevelopment or abnormal closure, of a normal anatomical tubular structure or opening.
Contrast this with agenesis which refers to the complete absence of any anatomical structure including its primordial precursors.
...
Article
PSA velocity
The PSA velocity (PSAV) is a statistically-derived measure of how the prostate specific antigen (PSA) changes over time, and has been used as a marker of how prostate malignancy progresses or regresses.
Any cancer grows over time and relative changes of tumor markers, such as PSA, would seem t...
Article
Monomelic
Monomelic is typically used to refer to a condition that is confined to only one limb. Examples of conditions that can be monomelic include fibrous dysplasia and melorheostosis.
See also
monostotic
polyostotic
monomelic
Article
Familial hypercholesterolemia
Familial hypercholesterolemia is a common autosomal dominant 1 condition resulting in hyperlipidemia.
Epidemiology
1 in 200 individuals are estimated to be carriers of at least one gene associated with familial hypercholesterolemia 1.
Pathology
Features of hyperlipidemia such as early/exces...
Article
BRAF
BRAF (B-Raf proto-oncogene serine/threonine-protein kinase) is a proto-oncogene, encoding for a serine/threonine protein kinase. Mutations of BRAF are the most common alteration of the RAS/MAPK pathway and these have been identified in a variety of tumors and congenital syndromes including 1-5: ...
Article
Anaplastic lymphoma kinase (ALK) gene rearrangements
Anaplastic lymphoma kinase (ALK) gene rearrangements are known to occur in association with several tumors. The genes code for an enzyme called anaplastic lymphoma kinase (ALK) or ALK tyrosine kinase receptor (also known as CD246) which is thought to play a role in brain development and exerts i...
Article
Amylase
Amylase is widely employed as a marker of acute pancreatitis and a significant elevation is diagnostic.
Physiology
α-amylase is a digestive enzyme that is predominantly secreted by the acinar cells of the exocrine pancreas. It is also secreted by the salivary glands. Pancreatic amylase is enco...
Article
MAPK pathway
The MAPK pathway (mitogen-activated protein kinase pathway) also known as the RAS/MAPK pathway is an oncogenic pathway and is most commonly involved in human cancers.
It consists of a membrane receptor tyrosine kinase which when bound to by a growth factor results in activation of the signal t...
Article
Lepidic growth
Lepidic growth is a pathological term referring to a pattern of cell proliferation along the lining of the alveolar structures of the lung as is seen in a subset of lung tumors 1.
History and etymology
‘lepidic’ was coined by the English pathologist John George Adam (1862-1926) whilst at McGil...
Article
Columnar alteration with prominent apical snouts and secretions
Columnar alteration with prominent apical snouts and secretions (CAPSS) is a pathological entity encountered when breast biopsies are done for investigation of punctate or amorphous calcifications. CAPSS involves the terminal ductal and lobular units (TDLU's).
It is sometimes classified under t...
Article
Metastatic axillary lymphadenopathy of unknown primary
Metastatic axillary lymphadenopathy of unknown primary can be a very challenging situation.
Pathology
Usual potential sites include:
occult breast cancer: the incidence of an axillary lymph node manifestation from an occult primary breast cancer is low, ranging from 0.3-0.8% of all patients ...
Article
Cyst
A cyst is an abnormal fluid-filled structure which is lined by epithelium; with one exception: lung cysts may contain gas or fluid. By contradistinction, a pseudocyst lacks an epithelial lining and instead has a vascular and fibrotic capsule.
Cysts are extremely common and found in most organs....
Article
Parathyroid proliferative disease
Parathyroid proliferative disease is the collective term for a spectrum of parathyroid disorders 1:
parathyroid adenoma
parathyroid carcinoma
parathyroid atypical adenoma: controversial entity
parathyroid hyperplasia
primary chief cell hyperplasia
primary water-clear cell hyperplasia (rare...
Article
Ependymal cells
Ependymal cells are one of the four main types of glial cells, and themselves encompass three types of cells 1:
ependymocytes: line the ventricles of the brain and central canal of the spinal cord
tanycytes: line the floor of the third ventricle overlying the median eminence of the hypothalam...
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