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.
16,929 results
Article
Propeller blade distribution (CT chest)
A propeller blade distribution on a CT chest is a type of variant pattern in those with interstitial lung disease where reticular changes and honeycombing when seen on sequential axial images from caudal (base) to cranial (apices) change from being predominantly posterior to predominantly anteri...
Article
Prostate Imaging-Reporting and Data System (PI-RADS)
PI-RADS (Prostate Imaging–Reporting and Data System) is a structured reporting scheme for multiparametric prostate MRI in the evaluation of suspected prostate cancer in treatment naive prostate glands. This article reflects version 2.1 (v2.1), published in 2019 and developed by an internationall...
Article
Ventriculitis
Ventriculitis refers to inflammation, usually due to infection, of the ependymal lining of the cerebral ventricles. It is most often due to concurrent meningitis.
Terminology
The entity or closely related variants have also been variously referred to as ependymitis, ventricular empyema, intrav...
Article
Cholangiocarcinoma
Cholangiocarcinomas (commonest type of bile duct cancers) are malignant epithelial tumors arising from the biliary tree, excluding the gallbladder or ampulla of Vater. Cholangiocarcinoma is the third most common primary hepatobiliary malignancy after hepatocellular carcinoma (HCC) and gallbladde...
Article
Ascites
Ascites (hydroperitoneum is a rare synonym) is defined as an abnormal amount of intraperitoneal fluid.
Terminology
Ascites (plural is the same word) tends to be reserved for relatively sizable amounts of peritoneal fluid. The amount has not been defined formally. It is noted physiologically, h...
Article
Perianal abscess
Perianal abscess refers to a formed infective-inflammatory collection within the perianal region. It forms part of the broader group of anorectal abscesses. They are often associated with perianal fistulae and are components of grades 2 and 4 fistulae of the St James’ University Hospital classif...
Article
Ischioanal fossa
The ischioanal (or ischiorectal) fossa is a fat-filled space of the perineum.
Gross anatomy
The ischioanal fossa is a paired triangular-shaped space lateral to the anal canal with an apex directed anteromedially towards the pubic symphysis. Each ischioanal fossa is separated from the other by...
Article
Choledochal cyst
Choledochal cysts represent congenital cystic dilatations of the biliary tree. Diagnosis relies on excluding other conditions as a cause of biliary duct dilatation, e.g. tumor, gallstone, inflammation.
Epidemiology
Choledochal cysts are rare, with an overall incidence of 1:100,000-150,000. The...
Article
Hamate
The hamate is one of the carpal bones, forms part of the distal carpal row and has a characteristic hook on its volar surface.
Gross anatomy
Osteology
The hamate has a wedge-shaped body. It bears an uncinate (unciform) hamulus (hook of hamate) which projects in a volar fashion from the distal...
Article
Baxter neuropathy
Baxter neuropathy is a nerve entrapment syndrome resulting from the compression of the inferior calcaneal nerve (Baxter nerve).
Clinical presentation
heel pain with maximal tenderness over the course of the inferior calcaneal nerve (on the plantar medial aspect of the foot and anterior to the ...
Article
Locked thumb metacarpophalangeal joint
Locked thumb metacarpophalangeal (MCP) joints are rare hyperextension injuries caused by the radial sesamoid preventing flexion 1,2.
Epidemiology
These injuries have been reported in all age groups but are most common in patients in their 20s 2. They can be due to ball sports, in particular do...
Article
Acetabulum
The acetabulum (plural: acetabula) is the large cup-shaped cavity on the anterolateral aspect of the pelvis that articulates with the femoral head to form the hip joint.
Gross anatomy
All three bones of the pelvis (the ilium, ischium, and pubis) together form the acetabulum. The three bones ar...
Article
Wallerian degeneration
Wallerian degeneration is the process of antegrade degeneration of the axons and their accompanying myelin sheaths due to a proximal axonal or neuronal cell body insult. It may result following neuronal loss due to cerebral infarction, trauma, necrosis, focal demyelination, or hemorrhage.
Path...
Article
Trapezium
The trapezium (also known as the greater multangular) is one of the eight carpal bones of the hand. It is the most lateral (radial) bone of the distal row, located between the scaphoid and the first metacarpal bone. It articulates with the scaphoid proximally, the trapezoid medially, and the thu...
Article
Erosive osteoarthritis
Erosive (inflammatory) osteoarthritis is a form of hand osteoarthritis (OA) where, as the name implies, there is an additional erosive/inflammatory component.
Epidemiology
There is marked female predilection (F:M ~12:1), typically presenting in the postmenopausal patient.
Clinical presentatio...
Article
Breast imaging-reporting and data system (BI-RADS) assessment category 5
BI-RADS 5 lesions under the BI-RADS (breast imaging reporting and data system) refer to breast lesions that are highly suspicious for malignancy, requiring appropriate action to be taken (i.e. biopsy and management as appropriate). BI-RADS 5 lesions have the characteristic morphology of breast c...
Article
Bullet-shaped vertebra
Bullet-shaped vertebra, also known as ovoid vertebra, refers to the anterior beaking of the vertebral body.
It is seen in the following conditions:
mucopolysaccharidosis
Hurler disease usually with inferior beaking
Morquio disease often with central beaking
achondroplasia
congenital hypoth...
Article
Central nervous system germinoma
Intracranial germinomas, also known as dysgerminomas or extra-gonadal seminomas, are a type of germ cell tumor and are predominantly seen in pediatric populations. They tend to occur in the midline, either at the pineal region (majority) or along the floor of the third ventricle/suprasellar regi...
Article
Hurler syndrome
Hurler syndrome is one of the mucopolysaccharidoses (MPS type I).
Epidemiology
The estimated incidence is ~1:100,000.
Clinical presentation
It manifests in the first years of life with intellectual disability, corneal clouding, deafness, and cardiac disease. Death usually occurs within the f...
Article
Mucopolysaccharidoses
Mucopolysaccharidoses (MPS) constitute a group of hereditary disorders, one of a number of lysosomal storage disorders, having in common an excessive accumulation of mucopolysaccharides secondary to deficiencies in specific enzymes (lysosomal hydrolases) responsible for degradation of mucopolysa...
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