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.

20 results found
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

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

Atypical small acinar proliferation

Atypical small acinar proliferations (ASAP) are premalignant lesions of the prostate, which can be found in as many as 5% of prostate biopsies. They are suspicious glands without adequate histologic atypia to establish a definitive diagnosis of prostate cancer. Some studies showed that there is ...
Article

Corpora amylacea

The corpora amylacea ("bodies of starch") are a histologic finding, encountered more frequently in the brain, prostate, lung, and uterus. The corpora amylacea are thought to be sulfated glycosaminoglycans 1. Some have described it as a localized amyloidosis 2.  In the prostate they appear to ar...
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

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

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.  Calculation The eGFR is calculated using a four variables Modification of Diet in Renal...
Article

Fistula

A fistula (plural: fistulae) is an abnormal connection between two epithelial surfaces such as between hollow organs, skin or vessels. Conventionally, the name of a specific fistula type is a combination of the two organs For discussions of specific fistulae please refer to individual articles....
Article

Hernia (general)

Hernias (or herniae) are a common pathological entity, in which an anatomical structure passes into an abnormal location via an opening. The opening may be a normal physiological aperture (e.g. hiatus hernia: stomach passes through the diaphragmatic esophageal hiatus) or pathological. Iatrogeni...
Article

Lactate dehydrogenase

Lactate dehydrogenase (LDH or LD) is a key enzyme in most cells, catalyzing the reversible conversion of pyruvate to L-lactate. Its contemporaneous main clinical uses are limited primarily to the investigation of hemolysis, serous collections and as a tumor marker. Physiology L-lactate dehydro...
Article

Lamellated

The term lamellated (or laminated which means the same thing) is a radiopathological term used to describe the layered appearance of many calculi, including those of the renal tract, the salivary glands, and the biliary tree. The internal structure of these calculi has been likened to that of an...
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

Multilocular cystic renal neoplasm of low malignant potential

Multilocular cystic renal neoplasm of low malignant potential is a low-grade adult renal tumor composed entirely of numerous cysts. The entity was previously known as multilocular cystic renal cell carcinoma, which usually had clear cell morphology, but was redefined in the 2016 WHO classificati...
Article

Prostate specific antigen

Prostate specific antigen (PSA) is currently used as a tumor marker for prostate adenocarcinoma. PSA is a 33 kilodalton glycoprotein produced in prostate epithelial cells. Its normal physiologic role is as a liquefying agent for seminal fluid; only a tiny amount leaks into the blood, therefore ...
Article

Prostate-specific membrane antigen

Prostate-specific membrane antigen (PSMA) (also known as glutamate carboxypeptidase II) is a type II transmembrane glycoprotein that has become an increasingly prominent imaging biomarker 1. PSMA has emerged as a useful target in PET imaging of prostate cancer, especially in the evaluation of sm...
Article

Prostatic acid phosphatase

Prostatic acid phosphatase (PAP) also known as prostatic specific acid phosphatase (PSAP) is an enzyme generated by prostatic glandular tissue. Usage It can be used in immunohistochemistry to identify prostatic tissue including prostatic epithelium and prostatic ducts and is usually expressed ...
Article

PSA density

The PSA density (PSAD), is a calculation performed at diagnosis and is the serum prostate specific antigen (PSA) level (ng/mL) divided by the volume of the prostate gland (mL)1. Prostate volume is calculated from TRUS measurements 2,3.  Alternatively, PSA density may be calculated using MRI mea...
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

Schiller-Duval body (histology)

Schiller-Duval body is a perivascular structure that can be found in 50% of testicular yolk sac tumors also known as endodermal sinus tumors. If present it is considered pathognomonic.  Pathology A central vessel is surrounded by tumor cells, and the cell-vessel complex is contained in a cysti...
Article

Urine

Urine represents the biofluid end-product of the renal filtration process. Normally it is a transparent, sterile, pale-yellow liquid (although clearly color varies with the person's hydration status).  Urine is one of the most easily-accessible biofluids in the human body and has been intensive...

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