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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

19 results found
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 t...
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

Brunner glands

Brunner glands are compound tubular submucosal glands found in the duodenum. They are only found proximal to the sphincter of Oddi. Related pathology Brunner gland hyperplasia Brunner gland adenoma
Article

CA 19-9

CA 19-9 (carbohydrate antigen 19-9 or cancer antigen 19-9) is a serum antigen (monosialoganglioside) that has increased diagnostic use in the management of several malignancies, mainly of hepatopancreaticobiliary origin. It is non-specific, however, and can rise in both malignant and non-maligna...
Article

CEA

Serum CEA (carcinoembryonic antigen) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumor markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue. Normal range of CEA is ...
Article

Circumferential resection margin

The circumferential resection margin (CRM) is a term used in rectal carcinoma excision surgery (such as total mesorectal excision (TME)). Pathologic evaluation of the resection margin on the excised rectum has been considered important for determining the risk of local recurrence. A margin of ≤...
Article

Diverticulum

Diverticula are outpouchings of a hollow viscus and can be either true or false. Occasionally a diverticulum is used in a more general sense to mean the outpouching of other anatomical structures, e.g. frontal intersinus septal cells are hypothesized to form as diverticula from the frontal sinu...
Article

Elevated vitamin B12

Elevated vitamin B12 (also known as hypervitaminosis B12 or hypercobalaminemia) is most important as a diagnostic and prognostic marker for malignant disease 1,3. Very high serum levels of vitamin B12 do not seem to have any observable deleterious effects 2. 
Article

Fecal calprotectin

Fecal calprotectin (FCAL) is a protein which is a marker of inflammation of the gut 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 chai...
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 t...
Article

Haggitt level

The Haggitt level is a histopathological term used for describing the degree of infiltration from a malignant polypoidal lesion. Levels of invasion 0: carcinoma in situ or intramucosal carcinoma 1: invasion of the submucosa, but limited to the head of the polyp 2: invasion extending into the...
Article

Kikuchi level

The Kikuchi level is a histopathological term used for describing the degree of infiltration of a sessile early invasive colorectal cancer1. Preoperative assessment of the level of invasion using this classification may decrease the incidence of unnecessary surgery for sessile polyps.  Levels o...
Article

KRAS mutation

KRAS (shortened name for the gene Kirsten RAt Sarcoma viral oncogene homolog) mutations are associated in a number of malignancies including:  certain adenocarcinomas of the lung colorectal carcinoma 1 pancreatic ductal adenocarcinoma Several germline KRAS mutations have also been found to b...
Article

Lipase

Lipase, more specifically pancreatic lipase, is an enzyme produced in the pancreas and is responsible for the digestion of fat molecules. It may be raised (hyperlipasemia) in numerous pancreatic, hepatobiliary and other diseases but is most commonly associated with acute pancreatitis. Physiolog...
Article

Macroamylasemia

Macroamylasemia is the presence of serum amylase of a large molecular size, seen in both otherwise healthy individuals, and also in various diseases. Amylase seems to be able to self-polymerize and/or form complexes with other blood proteins, e.g. immunoglobulins. Epidemiology Macroamylasemia ...
Article

Macrolipasemia

Macrolipasemia is the presence of serum lipase of a large molecular size, seen occasionally in otherwise healthy individuals, but more commonly in various diseases. Lipase is able to self-polymerize and/or form complexes with other blood proteins e.g. immunoglobulins. Epidemiology Epidemiologi...
Article

Metaplasia

Metaplasia is a general pathology term that refers to process when one cell type is replaced by another. It usually occurs in the context of a changed cellular environment to which the new cell type is better adapted 1. Examples include 2-5: Barrett esophagus: normal squamous epithelium replace...
Article

Tissue tropism

Tissue tropism is a phenomenon by which certain host tissues preferentially support the growth and proliferation of pathogens. This concept is central to the radiological evaluation of infectious disease.  Pathology As infections that display tissue tropism will thrive in certain tissue locati...
Article

Vitamin B3

Vitamin B3 (niacin or nicotinic acid) is a water-soluble vitamin, part of the vitamin B complex, that is an important part of the coenzyme nicotinamide adenine dinucleotide (NAD+) which is involved in many reactions of cellular metabolism. Related pathology pellagra is the clinical syndrome of...

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