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.
318 results found
Article
Lipoma
Lipomas are benign tumors composed of mature adipocytes. They are the most common soft tissue tumor, seen in ~2% of the population.
Epidemiology
Patients typically present in adulthood (5th-7th decades).
Associations
In some cases, multiple lipomas are associated with syndromes and other di...
Article
Pleomorphic adenoma of the salivary glands
Pleomorphic adenomas of the salivary glands, also known as benign mixed tumors (see below), are the most common salivary gland tumors. The salivary glands are the most common site of pleomorphic adenomas.
On imaging, they commonly present as well-circumscribed rounded masses, most commonly loca...
Article
Fecal calprotectin
Fecal calprotectin (FCAL) is a protein marker of gut inflammation. It is used as a diagnostic tool and marker of disease activity for Crohn disease and ulcerative colitis.
Biochemistry
Calprotectin is a protein complex from the S-100 family, which is formed of three polypeptide chains, two hea...
Article
Non-pulsatile tinnitus
Non-pulsatile tinnitus is a form of tinnitus where there is a continuous ringing sensation of the ears. It is thought to have a considerable subjective component in many individuals.
Pathology
Many factors have been postulated, inclusive of 1-5:
cerumen impaction
middle ear infection
medica...
Article
Cobalt
Cobalt (chemical symbol Co) is an essential trace element. Its most important function in humans is as the active metal atomic center of vitamin B12.
Chemistry
Basic chemistry
Cobalt is a shiny grey-silvery transition metal with an atomic number 27 and an atomic weight of 58.93 Daltons (Da). ...
Article
Flail mandible
A flail mandible is an uncommon type of comminuted fracture through the mandibular symphysis and bilateral condyle and/or rami which can result in posterior displacement and internal rotation of the mandibular bodies, eversion of the angles of the mandible, and glossoptosis. Together with concom...
Article
Inflammation
Inflammation is a response to noxious stimuli that can be acute or chronic.
The cardinal signs of inflammation include:
heat (calor)
redness (rubor)
swelling (tumor)
pain (dolor)
loss of tissue function (functio laesa)
Subtypes
Acute Inflammation
Acute inflammation occurs within the fir...
Article
Tumor spread through air spaces
Tumor spread through air spaces (STAS) is a pattern of invasion in lung adenocarcinoma. According to the 2015 WHO classification, tumor spread through air spaces is defined as “micropapillary clusters, solid nests, or single cells spreading within air spaces beyond the edge of the main tumor” 2,...
Article
Biotin
Biotin, less commonly known as vitamin B7, and previously known as vitamin H or coenzyme R, is a water-soluble vitamin, part of the vitamin B complex, and a coenzyme for many reactions, including gluconeogenesis and the synthesis of fatty acids and amino acids.
Biotin deficiency is very rare.
...
Article
Radiogenomics
Radiogenomics denotes the relationship between the imaging features of a particular disease and various genetic or molecular features. The former is referred to as an imaging phenotype, whereas the later as genomic phenotype.
Radiogenomics, therefore, provides a tool for clinicians to correlat...
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
Zinc
Zinc (chemical symbol Zn) is a trace element with a key role as a constituent of enzymes (e.g. carbonic anhydrase), as a part of zinc finger proteins vital for the correct folding of macromolecules (such as DNA), and as an important cellular messenger 3.
Chemistry
Basic chemistry
Zinc is a tr...
Article
Heavy metals
Heavy metals is a vague term referring to metals of toxicologic significance. While historically this referred to metals of a high density/mass, such as those in the lanthanides and actinides (on the periodic table), it now encompasses a broad array of elements, including some metalloids (e.g. a...
Article
Grocott-Gomori methenamine silver stain
Grocott-Gomori methenamine silver (GMS) stain is a histological stain frequently used to screen specimens for fungal organisms. The procedure relies on the presence of polysaccharides along the fungal cell wall.
During the staining process, chromic acid is first applied to the specimen which ox...
Article
Estimated glomerular filtration rate
The estimated glomerular filtration rate (eGFR) is widely used as a surrogate marker of renal function and is mathematically derived from the patient's serum creatinine, using their age, sex and ethnicity. There is some controversy over whether ethnicity should be included in the calculations.
...
Article
Eosinophilia
Eosinophilia is defined as an abnormally high level of eosinophils in the blood, this is usually defined as >500 cells/μL (normal eosinophil level: <450 cells/μL). Hypereosinophilia is defined as >1500 cells/μL and is usually due to hematological malignancy 1,2.
This article includes recommenda...
Article
Sessile
Sessile is a pathological term which is used for lesions that are attached by their base, that is they lack a stalk i.e. are not pedunculated. It is most commonly used for intraluminal polyps in the GI tract.
History and etymology
Sessile is derived from the Latin word "sessilis" which means s...
Article
S100
S100 is a family of cytoplasmic calcium-binding proteins expressed in numerous cell lines which can be targeted by immunohistochemistry. Staining for S100 is helpful in characterizing a number of tumors, including malignant melanoma, glial tumors, neurogenic tumors (e.g. schwannomas and neurofib...
Article
Aneurysm
Aneurysms are focal abnormal dilatation of a blood vessel. They typically occur in arteries; venous aneurysms are rare. Aneurysms may also occur in the heart.
Pathology
Pathological types
true aneurysm
false aneurysm (or pseudoaneurysm)
Etiology
Atherosclerotic
atherosclerosis
Non-athero...
Article
Adenoma-carcinoma sequence
The adenoma-carcinoma sequence refers to a stepwise pattern of mutational activation of oncogenes (e.g. K-ras) and inactivation of tumor suppressor genes (e.g. p53) that results in cancer. An oncogene is a gene that has the potential to cause cancer. In tumor cells, these are often mutated or ex...
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