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.
More than 200 results
Article
DNA
DNA (deoxyribonucleic acid) is a nucleic acid that encodes the genetic information (genome) necessary for RNA (ribonucleic acid) transcription (transcriptome) and protein synthesis (proteome) 1. It is contained in the nucleus of eukaryotic cells in the form of chromatin or chromosomes 7,8. Human...
Article
Dermolipoma
Dermolipomas are fat-containing epibulbar mass lesions of the lateral canthal area beneath the temporal or superotemporal bulbar conjunctivae. This should be differentiated from subconjunctival fat prolapse as they have different radiological features and treatment stratagies 4.
Epidemiology
...
Article
Sirenomelia
Sirenomelia, also known as the mermaid syndrome, is a rare congenital malformation characterized by the fusion of lower limb structures. The exact etiology of this disease is unknown.
Terminology
sirenomelia sequence
sirenomelia syndrome
Epidemiology
The estimated incidence is at ~1 in 60,0...
Article
Subconjunctival fat prolapse
Subconjunctival fat prolapse is an acquired herniation of intraconal fat due to the weakening of the Tenon capsule by normal aging, surgery, or trauma. It presents clinically with a fat-containing epibulbar mass in the lateral canthal area.
Epidemiology
Subconjunctival fat prolapse occurs mai...
Article
Gamekeeper's thumb
Gamekeeper's thumb, also known as skier's thumb or break-dancer's thumb, is an avulsion or rupture of the ulnar collateral ligament (UCL) of the first metacarpophalangeal joint.
Terminology
Skier's thumb refers to acute injury due to trauma, from hyperabduction of the thumb as it is caught by ...
Article
Diaphragma sellae
The diaphragma sellae is one of the folds (or reflections) of the dura mater. It covers the sella turcica and forms the roof over the pituitary fossa 1.
Gross anatomy
The diaphragma sellae consists of two horizontal leaves of dura mater on the sphenoid bone. It extends from the tuberculum sell...
Article
Chevron sign (achondroplasia)
The chevron sign refers to an inverted-V, or caret (^) shaped physis due to central depression of the metaphysis with focal protrusion of the adjacent epiphysis noted in children with achondroplasia. It is most commonly seen in the epiphysis of the distal femur and proximal tibia. It tends to di...
Article
Pott puffy tumor
Pott puffy tumor refers to a non-neoplastic complication of acute sinusitis. It is characterized by a primarily subgaleal collection, subperiosteal abscess, and osteomyelitis. It is usually related to infective pathologies of the frontal sinus.
Epidemiology
Although it may affect patients of a...
Article
Subdural empyema
Subdural empyema is a type of intracranial infection characterized by a suppurative collection between the dura mater and the arachnoid mater. It is commonly seen as a complication of sinusitis, otitis, mastoiditis, or surgical intervention.
On imaging, it tends to present as a subdural collect...
Article
Acute cerebellitis
Acute cerebellitis and acute cerebellar ataxia represent a spectrum of inflammatory processes characterized by sudden onset cerebellar dysfunction. It usually affects children and is related as a consequence of primary or secondary infection, or much less commonly as a result of a post-vaccinati...
Article
Superior peroneal retinaculum injuries
Superior peroneal retinaculum injuries refer to a spectrum of acute and chronic injuries to the superior peroneal retinaculum at the ankle. They are one of the causes of lateral ankle pain and instability.
Clinical presentation
Acutely, superior peroneal retinaculum injuries can present simil...
Article
Tolosa-Hunt syndrome
Tolosa-Hunt syndrome is an idiopathic inflammatory condition that involves the cavernous sinus and orbital apex and is essentially a clinical diagnosis of exclusion.
Epidemiology
The estimated incidence of Tolosa-Hunt syndrome is 1 per 1,000,000 person-years with an average age of onset at 41 ...
Article
Congenital pseudoarthrosis of the tibia
Congenital pseudoarthrosis of the tibia, or anterolateral bowing of the tibia with congenital dysplasia, describes abnormal bowing that can progress to a segment of bone loss simulating the appearance of a joint. The condition is usually apparent shortly after birth and rarely diagnosed after ag...
Article
Cardiac wall motion abnormalities
Cardiac wall motion abnormalities describe kinetic alterations in the cardiac wall motion during the cardiac cycle and have an effect on cardiac function. Cardiac wall motion abnormalities can be categorized with respect to their degree and their distribution pattern that is whether they are glo...
Article
Lymph node enlargement
Lymph node enlargement (rarely lymphadenomegaly) is often used synonymously with lymphadenopathy, which is not strictly correct.
Terminology
Lymphadenopathy (or adenopathy) is, if anything, a broader term than lymph node enlargement, referring to any pathology of lymph nodes, not necessarily r...
Article
Dead pixel artifact
Dead pixel artifact is an artifact seen in direct digital radiography systems where a detector element fails to receive a proper signal and therefore appears as a bright white dot in an x-ray image.
A defective pixel on the display monitor can also lead to a white dot appearance (termed stuck p...
Article
Photon-counting computed tomography
Photon-counting computed tomography uses energy-resolving detectors, thereby enabling scanning at multiple energies.
Technique
Physical principles
Clinical CT systems rely on energy-integrating detectors, which measure the total x-ray energy reaching the detector during the measurement period...
Article
Supracondylar humeral fracture
Supracondylar humeral fractures, often simply referred to as supracondylar fractures, are a classic pediatric injury which requires vigilance as imaging findings can be subtle.
Epidemiology
Simple supracondylar fractures are typically seen in younger children, and are uncommon in adults; 90% a...
Article
Electron
Electrons are fundamental subatomic particles involved in various atomic processes, including those relevant to X-ray production and interactions with matter.
Properties
Subatomic particle with a mass of 9.109 × 10⁻³¹ kg (~0.0005 relative mass to proton).
Carries a -1 charge (-1.6 × 10⁻19 C)....
Article
Inferior mesenteric vein
The inferior mesenteric vein (IMV) drains blood from the distal portion of the colon as well as the rectum (i.e. the hindgut).
Gross anatomy
Origin and course
The inferior mesenteric vein drains the mesenteric arcade of the hindgut (comprising of distal transverse, descending, and sigmoid co...
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