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.
16,883 results found
Article
Radial bands sign (tuberous sclerosis)
The radial bands sign, also known as radial migration bands, refers to linear bands seen on MRI, radiating from the periventricular white matter to the subcortical region, thought to be specific for tuberous sclerosis 1,2.
Pathology
The exact pathogenesis of radial bands is uncertain, but they...
Article
Floating knee
Floating knees occur when there are ipsilateral fractures of both femoral and tibial shafts. These are relatively rare injuries with reported poor outcomes.
Clinical presentation
The usual presentation is a combined closed midshaft femoral fracture and open midshaft tibial fracture. Vascular i...
Article
Compressive myelopathy
Compressive myelopathy refers to neurological deficits that result from compression of the spinal cord. It most commonly occurs in the cervical spinal cord.
Pathology
Any cause of spinal canal stenosis including cervical spondylosis (endplate changes, disc herniation, osteophytes, facet joint...
Article
Owl-eyes sign (spinal cord)
The owl-eyes sign, also known as snake-eyes sign or fried-eggs sign, represents bilaterally symmetric circular to ovoid foci of high T2-weighted signals in the anterior horn cells of the spinal cord and is seen on axial MR imaging. The sagittal corollary is a "pencil-like" vertical linear high T...
Article
Pulmonary artery pseudoaneurysm
Pulmonary artery pseudoaneurysm refers to a pseudoaneurysm arising from the pulmonary arteries.
Pathology
A pseudoaneurysm results from a tear or disruption of all three layers of the vessel wall. Extravasated blood is contained by compressed extravascular tissue or a clot, which makes up the ...
Article
Right-sided aortic arch
Right-sided aortic arch is a type of aortic arch variant characterized by the aortic arch coursing to the right of the trachea. Different configurations can be found based on the supra-aortic branching patterns, with the two most common patterns being the right-sided aortic arch with mirror imag...
Article
Lacunar stroke syndrome
Lacunar stroke syndrome is a description of the clinical syndrome that results from a lacunar infarct.
Each of the five classical lacunar syndromes has a relatively distinct symptom complex. Symptoms may occur suddenly, progressively, or in a fluctuating manner (e.g. the capsular warning syndr...
Article
Spondylolysis
Spondylolysis, commonly known as pars interarticularis defect or pars defect, is a defect in the pars interarticularis, the portion of the vertebral neural arch that connects the superior and inferior articular facets.
Epidemiology
Spondylolysis is present in ~5% of the population 2 and higher...
Article
AO/OTA classification of distal femur fractures
The AO/OTA classification of distal femoral fractures is a commonly used fracture classification system in orthopedic trauma.
Classification
In the AO/OTA classification system, the distal femur system's prefix is 33, indicating the femur (3) and the distal portion of the femur (3) 1. Each lo...
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
Scaphotrapeziotrapezoidal arthritis
Scaphotrapeziotrapezoidal (STT) or triscaphe joint arthritis is common, occurring on ~9% (range 2-16%) of wrist radiographs 3,4. It is typically degenerative (i.e. osteoarthritis) affecting the triscaphe articulation and presents with radial-sided wrist or base of thumb pain in patients over 50 ...
Article
Pulmonary artery atresia
Pulmonary artery atresia (or sometimes known as pulmonary atresia) is a congenital cardiovascular anomaly in which there is complete disruption between the right ventricular outflow tract (RVOT) and the pulmonary trunk.
Epidemiology
The estimated incidence is 1 in 10,000 births.
Pathology
Th...
Article
Superficial CD34-positive fibroblastic tumor
Superficial CD34-positive fibroblastic tumors (SCPFT) or PRDM10-rearranged soft tissue tumors are rare low-grade mesenchymal neoplasms of the dermis and subcutis 1-3 that have been just added to the WHO classification of soft tissue tumors in 2020 2,3.
Epidemiology
Superficial CD34-positive fi...
Article
Optic pathway glioma
Optic pathway gliomas are relatively uncommon tumors, with a variable clinical course and usually seen in the setting of neurofibromatosis type I (NF1). Histologically the majority are pilocytic astrocytomas.
They are characterized by imaging by an enlarged optic nerve seen either on CT or MRI....
Article
Machine learning processes
The specifics of how a machine learning algorithm is trained to recognize certain features and thereby become able to make accurate predictions on new examples varies depending on the type of data being used and the algorithm architecture. Four of the most commonly used learning processes are:
...
Article
Periaqueductal grey matter
Periaqueductal grey (PAG) matter is a column of grey matter that surrounds the cerebral aqueduct of Sylvius in the midbrain. The periaqueductal grey matter extends from the superior border of the midbrain (which forms the posterior aspect of the floor of the third ventricle), inferiorly towards ...
Article
Uremic encephalopathy
Uremic encephalopathy is an acquired toxic syndrome characterized by delirium in patients with untreated or inadequately treated acute or chronic kidney disease 13. Uremic encephalopathy is often associated with lethargy and confusion in the acute phase, which can progress to seizures, coma, or ...
Article
Dentate nucleus
The dentate nucleus is the largest and most lateral of the cerebellar nuclei, located medially within each cerebellar hemisphere, just posterolateral to the fourth ventricle 1.
It is part of the triangle of Guillain and Mollaret, connected to the contralateral red nucleus via the superior cereb...
Article
Lipohemarthrosis
Lipohemarthrosis results from an intra-articular fracture with escape of fat and blood from the bone marrow into the joint, and is most frequently seen in the knee, associated with a tibial plateau fracture or distal femoral fracture; rarely a patellar fracture. They have also been described in ...
Article
Classification system for malformations of cortical development
The classification system for malformations of cortical development organizes myriad conditions into one of three major underlying groups according to the main underlying mechanism:
group I: abnormal cell proliferation or apoptosis
group II: abnormal neuronal migration
group III: abnormal cor...
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