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.
16,873 results found
Article
Excessive dynamic airway collapse
Excessive dynamic airway collapse (EDAC) refers to a dynamic form of central airway obstruction characterized by a decrease of ≥50% (some publications suggest >70% ref) in the cross-sectional area of the tracheobronchial lumen. Diagnosis is usually confirmed by dynamic cross-sectional imaging st...
Article
Common hepatic duct
The common hepatic duct (CHD) is formed by the right and left hepatic ducts junction. It joins the cystic duct to form the common bile duct (CBD). It is approximately 4 cm long and 4 mm in diameter, typically.
Together with the cystic duct (laterally) and cystic artery (superiorly), they form ...
Article
Meningeal hemangiopericytoma (historical)
Hemangiopericytomas of the meninges are rare tumors of the meninges, now considered to be an aggressive form of solitary fibrous tumors of the dura. They often present as large and locally aggressive dural masses, frequently extending through the skull vault. They are difficult to distinguish on...
Article
Osteonecrosis of the femoral head
Osteonecrosis of the femoral head, previously known as avascular necrosis (AVN) of the hip, is the most common site for osteonecrosis, presumably due to a combination of precarious blood supply and high loading when standing.
Idiopathic osteonecrosis of the femoral head epiphysis in children (...
Article
Systemic lupus erythematosus (CNS manifestations)
Central nervous system manifestations of systemic lupus erythematosus (CNS lupus), also known as neuropsychiatric systemic lupus erythematosus (NPSLE), describe a very diverse range of neuropsychiatric manifestations that are secondary to systemic lupus erythematosus (SLE) in the central nervous...
Article
Hemiplegic migraine
Hemiplegic migraines are an uncommon type of migraine with aura wherein patients present with usually reversible motor weakness, typically unilateral. They can be challenging to distinguish from seizure with Todd paresis or ischemic stroke, even with the benefit of MRI 1.
Epidemiology
Compared...
Article
Medulloepithelioma of the brain
Medulloepitheliomas of the brain are rare, highly malignant, primitive embryonic tumors derived from the primitive medullary plate and neural tube. These tumors, once considered distinct entities, are now thought to be a pattern of embryonal tumors with multilayered rosettes. Please refer to tha...
Article
Anal atresia
Anal atresia, or imperforate anus, refers to a spectrum of anorectal abnormalities ranging from a membranous separation to complete absence of the anus.
Epidemiology
The estimated incidence is 1 in 5000 live births.
Associations
There are frequent associations with other congenital abnormali...
Article
Flow-diverter stent
Flow-diverter stents are important devices in the management of intracranial aneurysms in both acute and elective settings, especially ones that are large, broad-necked, or fusiform.
Complications
Understanding the complication rates is important in obtaining informed consent from patients. In...
Article
Chemical shift artifact
Chemical shift artifact or misregistration is a type of MRI artifact. It is a common finding on some MRI sequences and used in magnetic resonance spectroscopy (MRS). This artifact occurs in the frequency-encoding direction and is due to spatial misregistration of fat and water molecules.
Chemi...
Article
Small bowel mesentery internal hernia
Small bowel mesentery internal hernias (alternative plural: herniae) are a form of internal bowel herniation involving protrusions of viscera through defects in the peritoneum or bowel mesentery.
Epidemiology
This type of internal herniation is more often seen in neonates than in adults ref.
...
Article
External auditory canal cholesteatoma
External auditory canal cholesteatomas are a rare subtype of acquired cholesteatoma.
Epidemiology
The external acoustic canal is a rare location for a cholesteatoma with an estimated incidence of around 1.2 per 1,000 new otological patients ref. The overall incidence rate in one large study wa...
Article
Tracheomalacia (differential)
A dilated trachea has numerous causes, and in almost all cases represents tracheomalacia (increased size and increased compliance).
As is almost always the case, various diameters have been used. Typical figures include >26 mm in men, >23 mm in women or >30 mm for both genders ref.
Although ma...
Article
Critical zone in rotator cuff tendons
The critical zone of the rotator cuff is an area approximately 8-15 mm from the insertion of the rotator cuff tendons onto the greater tubercle of the humeral head, mainly within the supraspinatus tendon. This is a watershed zone between the anterior and posterior circumflex humeral, thoracoacro...
Article
Ligamentum nuchae
The ligamentum nuchae or nuchal ligament is a large median ligament composed of tendons and fascia located between the posterior muscles of the neck.
Gross anatomy
The ligament nuchae covers the spines of C1 to C6 vertebrae. It is a superior and posterior extension of the supraspinous ligament...
Article
Rosette-forming glioneuronal tumors
Rosette-forming glioneuronal tumors (RGNTs) are rare, usually midline, tumors that involve the fourth ventricle and/or aqueduct of Sylvius.
Although relatively well-circumscribed on MRI and clinically indolent, they often invade surrounding tissues, involving the cerebellum, pons and even the ...
Article
Reye syndrome
Reye syndrome is a rare pediatric condition characterized by acute onset encephalopathy, severe vomiting and fatty liver failure. It typically presents in children recovering from a viral illness, most commonly influenza or chickenpox 1.
Epidemiology
Reye syndrome is usually seen between the ...
Article
Myocardium
The myocardium defines the middle layer of the cardiac wall between the endocardium and the pericardium and forms the muscular part of the heart.
Gross anatomy
The myocardium represents the middle layer of the cardiac wall. It is located between the endocardium and the epicardial layer of the ...
Article
Essex-Lopresti fracture-dislocation
Essex-Lopresti fracture-dislocation is characterized by a fracture of the radial head, dislocation of the distal radioulnar joint and rupture of the antebrachial interosseous membrane 3.
Epidemiology
As little as 20% of Essex-Lopresti fracture-dislocations are recognized at the time of initial...
Article
Crohn disease
Crohn disease, also known as regional enteritis, is an idiopathic inflammatory bowel disease characterized by widespread discontinuous gastrointestinal tract inflammation. The terminal ileum and proximal colon are most often affected. Extraintestinal disease is common.
Epidemiology
The diagnos...
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