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.
16,931 results
Article
Polyglandular autoimmune syndromes
Polyglandular autoimmune syndromes (PAS) are a rare set of diseases characterized by the presence of ≥2 autoimmune endocrine disease.
Pathology
Three types of PAS have been described.
PAS type I
a.k.a. APECED (autoimmune polyendocrinopathy, candidiasis and ectodermal dystrophy) or MEDAC (mu...
Article
Nephrotic syndrome
Nephrotic syndrome results from loss of plasma proteins in the urine and characterized by hypoalbuminemia, hyperalbuminuria, hyperlipidemia, and edema. It may be caused by primary (idiopathic) renal disease or by a variety of secondary causes.
Clinical presentation
Patients present with marked...
Article
Half-value layer
Half-value layer (HVL) is the thickness of a material required to reduce the air kerma of an x-ray or gamma ray to half its original value. It applies to narrow beam geometry only, as with broad-beam geometry, a greater amount of scatter will reach the detector, overestimating the degree of atte...
Article
Gastrointestinal tract
The gastrointestinal (GI) tract (TA: systema digestorium) includes any part of the oral cavity, oropharynx, hypopharynx, esophagus, stomach, small bowel, colon, appendix, rectum and anal canal.
Terminology
The terms gastrointestinal system, alimentary canal, digestive system and digestive tra...
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
Rokitansky-Aschoff sinuses
Rokitansky-Aschoff sinuses are diverticula of the gallbladder wall which may be microscopic or macroscopic. Histologically, they are outpouchings of gallbladder mucosa that sit within the gallbladder muscle layer.
Related pathology
They are not themselves considered abnormal but may be associa...
Article
Aerodigestive tract
The aerodigestive tract is a non-TA descriptive collective term for the respiratory tract and proximal portion of the digestive tract. As it is a non-standard term, its precise components vary somewhat with the context in which the term is being employed.
Terminology
Definitions of what precis...
Article
Oropharynx
The oropharynx forms part of the pharynx, being the continuation of the oral cavity and nasopharynx superiorly, and the larynx and hypopharynx inferiorly. It also forms part of the upper respiratory tract and the gastrointestinal tract.
Its mucosa layer is continuous with the oral cavity, its s...
Article
Facial vein
The facial vein (previously known as the anterior facial vein) is the continuation of the angular vein and joins the anterior branch of the retromandibular vein to form the common facial vein 1-3.
Gross anatomy
At the level of the lower margin of the orbit, the angular vein becomes the facial ...
Article
Nutcracker syndrome
Nutcracker syndrome is a vascular compression disorder that refers to the compression of the left renal vein, most commonly between the superior mesenteric artery (SMA) and aorta, although other variations can exist 1. This can lead to renal venous hypertension, resulting in the rupture of thin-...
Article
Calyceal diverticulum
Calyceal diverticula, also known as pyelocalyceal diverticula, are outpouchings of the renal calyx or pelvis into the renal cortex. These diverticula are lined with transitional cell epithelium.
Epidemiology
Relatively uncommon, historically seen in 0.21% to 0.60% of intravenous urograms (IVU)...
Article
Intravenous urography
Intravenous urography (IVU) is a radiographic study of the renal parenchyma, pelvicalyceal system, ureters and urinary bladder using intravenous contrast medium. This exam has been largely replaced by CT urography.
Terminology
The term "urography" refers to evaluation of the entire urinary tr...
Article
CT urography (protocol)
CT urography (CTU or CT IVU), also known as CT intravenous pyelography (CT IVP), has now largely replaced traditional IVU in imaging the genitourinary tract. It gives both anatomical and functional information, albeit with a relatively higher dose of radiation.
Indications
hematuria
urothelia...
Article
Ureteral stricture
Ureteral or ureteric strictures are narrowing of the ureter that result in functional obstruction. They can occur anywhere along the ureter but are commonly seen at the ureteropelvic junction.
Epidemiology
The incidence of post-ureteroscopy strictures has increased from 0.5 to 1.4% 1,2. Studie...
Article
Omentum
An omentum is a double layer of peritoneum that attaches the stomach to another viscus:
the greater omentum hangs from the greater curvature of the stomach like an apron
the lesser omentum attaches the lesser curvature of the stomach to the liver superiorly
Gross anatomy
Greater omentum
The...
Article
Gastrosplenic ligament
The gastrosplenic ligament is a peritoneal ligament which is formed by ventral part of the dorsal mesentery.
Gross anatomy
The gastrosplenic ligament extends from the greater curvature of the stomach to the hilum of the spleen.
It contains
the short gastric arteries.
the left gastroepiploi...
Article
Swyer-James syndrome
Swyer-James syndrome, also known as Swyer-James-MacLeod syndrome and Bret syndrome, is a rare lung condition that manifests as unilateral hemithorax lucency as a result of postinfectious obliterative bronchiolitis.
Epidemiology
The condition typically follows a viral respiratory infection suc...
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...
Article
Kidneys
The kidneys are paired retroperitoneal organs that lie at the level of the T12 to L3 vertebral bodies.
Gross anatomy
Location
The kidneys are located to either side of the vertebral column in the perirenal space of the retroperitoneum, within the posterior abdominal wall. The long axis of the...
Article
Kugel artery
An uncommon variant of coronary arterial anatomy, Kugel artery was originally described as an anastomotic communication between branches of the proximal left circumflex artery with the distal right coronary artery. These coronary trunks often communicate indirectly through atrial anastomotic net...
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