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
Citric acid cycle
The citric acid cycle, also known as the Krebs cycle or tricarboxylic acid cycle, is a central metabolic pathway in cells. It involves a series of chemical reactions that oxidize acetyl-CoA derived from carbohydrates, fats, and proteins to produce energy in the form of ATP and electron carriers ...
Article
Isocitrate dehydrogenase (IDH)
Isocitrate dehydrogenase (IDH) is an enzyme located within the cytoplasm, peroxisomes and mitochondria. Mutations of the IDH genes are important in a variety of diseases. They form the basis of the classification of diffuse adult-type gliomas in the WHO classification of brain tumors 7 with emer...
Article
Circumferential resection margin
Circumferential resection margin (CRM) is a term used to denote the standard plane of excision of total mesorectal excision, used for resection of rectal cancers. The anatomic correlate is the mesorectal fascia. The distance between tumor tissue or satellite tumor deposits and the mesorectal fas...
Article
Epidermal inclusion cyst
Epidermal inclusion cysts or epidermal cysts are common cutaneous lesions that represent proliferation of squamous epithelium within a confined space in the dermis or subdermis.
Terminology
These are occasionally termed sebaceous cysts, although this is a misnomer as the lesion does not origin...
Article
Pandemic
The epidemiological term, pandemic is applied to an outbreak of disease that has spread across the globe, or in other words, an epidemic that has crossed many regions, borders and multiple continents. Some of the largest pandemics in history include the bubonic plague in the 14th century and the...
Article
Cortical laminar necrosis
Cortical laminar necrosis, also known as pseudolaminar necrosis, is necrosis of cortical neurons in situations when the supply of oxygen and glucose is inadequate to meet regional demands. This is often encountered in cardiac arrest, global hypoxia and hypoglycemia.
It should not be confused wi...
Article
PSA density
The PSA density (PSAD) is calculated at diagnosis and is the serum prostate-specific antigen (PSA) level (ng/mL) divided by the prostate gland's volume (mL), resulting in a value in the units ng/mL2 1. Prostate volume is calculated from TRUS measurements, MRI measurements or, less commonly, rese...
Article
Klebsiella
Klebsiella is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria, which is relatively commonly encountered in the healthcare environment. It has numerous species, including K. pneumoniae, K. aerogenes, and K. rhinoscleromatis 1. Klebsiella may cause a range of infections, most commo...
Article
Calponin
Calponin is an actin-binding protein regulating actin/myosin interaction in smooth muscle and non-muscle cells 1,2. It inhibits actin-activated myosin ATPase and stabilizes the actin cytoskeleton. It also serves as a target in immunohistochemistry where it can be used for the identification of m...
Article
Thyroseq
Thyroseq® is an expanded gene classifier test designed for further evaluation of indeterminate thyroid nodules on fine needle aspiration (FNA). In particular, it is designed to further evaluate nodules that show atypia of undetermined significance/follicular lesion of undetermined significance (...
Article
Erythrocyte sedimentation rate
Erythrocyte sedimentation rate (ESR) is a non-specific marker of acute inflammation which is seen in a very wide spectrum of pathologies. It has been sidelined by the use of C-reactive protein and other acute phase markers but it still has an important role to play in the management of some cond...
Article
Greater tubercle fracture of the shoulder
Greater tubercle/tuberosity fractures of the shoulder are a subtype of proximal humeral fractures.
Gross anatomy
The greater tubercle is the most lateral bony part of the shoulder. It is the site where three of the rotator cuffs insert to abduct or laterally rotate the shoulder joint (supraspi...
Article
Hydrogen
Hydrogen (chemical symbol H) is one of the basic organic elements, and all organic compounds contain hydrogen. It is the commonest element in the visible universe comprising greater than 75% of all matter.
Chemistry
Physical chemistry
Hydrogen is an odorless, tasteless and colourless gas. It ...
Article
Psammoma bodies
Psammoma bodies are round microscopic calcific collections. It is a form of dystrophic calcification. Necrotic cells form the focus for surrounding calcific deposition. They have a lamellated concentric calcified structure, sometimes large enough to be seen on CT.
Psammoma bodies are found in ...
Article
Desmoplasia
Desmoplasia, also known as a desmoplastic reaction, is the term used by pathologists to refer to the growth of fibrous tissue around disease, usually cancer. However in dermatopathology, desmoplasia may also be seen with benign, as well as malignant, conditions.
Terminology
Pathologists prefer...
Article
DNA
DNA (deoxyribonucleic acid) is a nucleic acid that encodes the genetic information (genome) necessary for RNA (ribonucleic acid) transcription (transcriptome) and protein synthesis (proteome) 1. It is contained in the nucleus of eukaryotic cells in the form of chromatin or chromosomes 7,8.
Mole...
Article
Glucagon
Glucagon is a polypeptide hormone central to the regulation of glucose homeostasis, acting as an antagonist to insulin. In imaging, it is used as an antiperistaltic agent in GI studies, although its clinical efficacy is controversial.
Structure
Glucagon is a 29-amino acid polypeptide hormone ...
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
Human coronavirus
The human coronaviruses (hCoVs), members of the family Coronaviridae, are enveloped RNA viruses that affect humans, mammals and birds, causing both acute and chronic illnesses.
Four of the seven known human coronaviruses usually cause a mild coryzal illness only, these are HKU1, NL63, OC43, and...
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...
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