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.
321 results found
Article
14-3-3 protein
14-3-3 proteins are found in the cerebrospinal fluid (CSF) and are currently used to help identify patients with sporadic Creutzfeldt-Jakob disease (sCJD).
Seven distinct 14-3-3 proteins have been found in humans.
In diagnosing sCJD, the sensitivity of 14-3-3 protein is 92%, and its specifici...
Article
1p19q codeletion
1p19q codeletion stands for the combined loss of the short arm chromosome 1 (i.e. 1p) and the long arm of chromosome 19 (i.e. 19q) and is recognized as a genetic marker predictive of therapeutic response to both chemotherapy and combined chemoradiotherapy and overall longer survival in patients ...
Article
2-hydroxyglutarate
2-hydroxyglutarate (2HG) is a metabolite that accumulates in the brains of patients with IDH1 mutated (IDH1 positive) brain tumors, particularly diffuse low-grade gliomas. Although not in widespread clinical use, it is likely that 2-hydroxyglutarate, which resonates at 2.25 ppm, will be able to ...
Article
Acanthosis nigricans
Acanthosis nigricans is a cutaneous disorder characterized by symmetric hyperpigmented velvety plaques on the neck, axillae, antecubital and popliteal fossae, inframammary, and groin areas. It is associated with acquired lipodystrophy.
Pathology
The benign form of acanthosis nigricans is assoc...
Article
Adenocarcinoma (endometrium)
Endometrial adenocarcinoma (EAC) is the commonest histological subtype of endometrial cancer and accounts for up to 90% of such cases 1.
Pathology
Histological subtypes
endometrioid carcinoma
serous adenocarcinoma of the endometrium
clear cell adenocarcinoma of the endometrium
mixed adeno...
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...
Article
Ahumada-Del Castillo syndrome
Ahumada-Del Castillo syndrome is a rare endocrine disorder affecting adult females, which is characterized by galactorrhea-amenorrhea not associated with pregnancy with estrogen deficiency and decreased urinary gonadotropin levels.
Clinical presentation
lactation not associated with breastfeed...
Article
Alcian blue stain
Alcian blue stain is a histological stain utilized for the identification of extracellular matrix proteoglycans, like glycosaminoglycans and hyaluronic acid 1, commonly in connective tissue and epithelial malignant neoplasms 2, and also Barrett esophagus, where it can highlight mucosal intestina...
Article
Alpha-fetoprotein
Alpha-fetoprotein (AFP) is an important plasma protein synthesized by the yolk sac and fetal liver. In adults, its main utility is as a tumor marker, primarily for hepatocellular carcinoma or teratoma. Functionally it is the fetal homologue of albumin, i.e. it acts as a major carrier protein in ...
Article
Alpha-thalassemia intellectual disability syndrome X-linked (ATRX) gene (tumor marker)
Alpha-thalassemia intellectual disability syndrome X-linked (ATRX) gene is an important genomic marker of gliomas and is either intact (ATRX-wildtype) or mutated (ATRX-mutant) and is correlated with other important genomic markers including IDH, 1p19q codeletion, and p53 expression 1,2.
ATRX a...
Article
Alzheimer type I glia
Alzheimer type I glia are a type of glial cell. They are large multinucleated astrocytes encountered in glial tumors and progressive multifocal leukoencephalopathy (PML) 1.
Article
Alzheimer type II glia
Alzheimer type II glia are a type of glial cell. They are a pathological reactive astrocyte seen in the brain, unrelated to Alzheimer disease. They are seen most frequently in Wilson disease, but also in other systemic metabolic disorders, particularly those with elevated ammonia levels, typical...
Article
Amino acids
Amino acids are the monomeric building blocks of proteins. Amino acids concatenate into chains, which are arbitrarily divided into peptides, polypeptides, or proteins according to chain length. Generally, chains of 10 or fewer amino acids are deemed to be peptides, chain length from 10-100 are p...
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
Anemia
Anemia is the presence of reduced hemoglobin in the blood. Formally, the World Health Organizatiοn (WHO) defines anemia by the hemoglobin concentration in the blood according to age and sex 1:
adult men: <130 g/L
adult women: <120 g/L
Values for pregnant women and children are different.
Cli...
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
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
Angiotensin converting enzyme
Angiotensin converting enzyme (ACE) is a central component of the renin-angiotensin system (RAS) which assists in blood pressure control by regulating the volume of fluids in the body.
Normal individuals may have a small volume of the angiotensin converting enzyme circulating in their blood.
M...
Article
Antineutrophil cytoplasmic antibody
Antineutrophil cytoplasmic antibodies (ANCAs) are a heterogenous class of IgG autoantibodies raised against the cellular contents of neutrophils, monocytes and endothelial cells 1. Under indirect immunofluorescence (IIF) microscopy, three ANCA staining patterns are observed, based on the varying...
Article
Antinuclear antibody
Antinuclear antibodies (ANAs) are a heterogenous class of autoantibodies raised against antigens present in the cell nucleus, including nucleic acids themselves and the enzymes involved in their processing. Under indirect immunofluorescence (IIF) microscopy, four major ANA staining patterns are ...
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