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.
16,924 results
Article
Elastofibroma dorsi
Elastofibroma dorsi, a benign soft-tissue tumor, is distinctly situated in the infrascapular or subscapular region, being bilateral close to a third of cases. On imaging, it presents as a poorly defined soft-tissue mass with CT attenuation closely resembling adjacent skeletal muscle.
Epidemiolo...
Article
Menstrual cup
The menstrual cup is a reusable silicone device designed to be an alternative to tampons and sanitary pads. Various different brands are available but they all have the same shape.
It can be observed on all forms of abdominal imaging and it is worth being familiar with its normal appearances.
...
Article
Sesamoid
Sesamoids, also known as sesamoid bones, are focal areas of ossification within tendons as they pass over joints 1. They can also occur in ligaments and usually measure a few millimeters in diameter. Their function is purported to be to alter the direction of the tendon and modify pressure, ther...
Article
Taylor dysplasia
Taylor dysplasia is a type of focal cortical dysplasia and a common cause of refractory epilepsy. Under both the Palmini classification and the Blumcke classification of focal cortical dysplasia, Taylor dysplasia is classified as type II.
For further discussion of the radiographic features ple...
Article
Mirizzi syndrome
Mirizzi syndrome refers to an uncommon phenomenon that results from extrinsic compression of an extrahepatic biliary duct from one or more calculi within the cystic duct or gallbladder. It is a functional hepatic syndrome but can often present with biliary duct dilatation and can mimic other hep...
Article
Total knee arthroplasty
Total knee arthroplasty (TKA), or total knee replacement (TKR), or tricompartmental knee replacement is an orthopedic procedure whereby the three articular surfaces of the knee (femoral, tibial, and patellar) are replaced by prosthetic components.
TKA is the most common joint arthroplasty perfo...
Article
Microtia
Microtia refers to a small pinna of the ear, when is it completely absent it is termed anotia.
Epidemiology
The estimated incidence at around 1:9000 live births. It is more common in males and there is a recognized right sided predilection.
Pathology
Associations
Microtia can be associated ...
Article
de Carvalho index (knee)
The de Carvalho index is used to measure patellar height and identify patella alta. It is similar to the Caton-Deschamps index and relies upon the length of the patellar articular surface and its distance from the tibia. This helps in reducing erroneous measurements in those with long patella bo...
Article
Adrenal washout
Adrenal washout can be calculated using the density value of an adrenal mass on non-enhanced, portal venous phase and 15-minute delayed CT scans (density measured in Hounsfield units (HU)). It is primarily used to diagnose adrenal adenoma.
absolute washout
[(HUportal venous phase) - (HUdelayed...
Article
External auditory canal atresia
External auditory canal atresia, also known as congenital aural atresia, is characterized by complete or incomplete bony atresia of the external auditory canal (EAC), often in association with a dysplastic auricle and an abnormal middle ear cavity or ossicles.
Epidemiology
The incidence is 1 i...
Article
Proximal radio-ulnar synostosis
Proximal radio-ulnar synostosis is an upper limb skeletal malformation characterized by bony fusion at the proximal aspect of the radius and ulna. The proximal third is considered the most common site of the radio-ulnar synostoses.
Epidemiology
Proximal radioulnar synostoses are rare occurren...
Article
Crescent sign (osteonecrosis)
The crescent sign refers to a linear cleft due to a subchondral fracture in the setting of osteonecrosis.
It was originally described as a radiographic finding, however, it can also be seen on cross-sectional imaging.
In the setting of Legg-Calve-Perthes disease, it heralds the beginning of th...
Article
Metanephric adenofibroma
Metanephric adenofibroma, originally referred to as 'nephrogenic adenofibroma', is a rare, biphasic and benign metanephric tumor.
Epidemiology
Metanephric adenofibroma typically occurs in children and young adults with a mean age of 13 years 1,3.
Clinical presentation
Patients present with ...
Article
Arcuate sign (knee)
The arcuate sign is often a subtle but important finding on knee x-rays and represents an avulsion fracture of the proximal fibula at the site of insertion of the arcuate ligament complex, and is usually associated with cruciate ligament injury (~90% of cases) 2. The fracture fragment is attache...
Article
Incisional hernia
Incisional hernias (alternative plural: herniae) are relatively common and along with parastomal hernias, umbilical hernias, paraumbilical hernias, and Spigelian hernias, they are usually anterior abdominal hernias.
Epidemiology
Incisional hernias usually develop within a few months of surgery...
Article
Creutzfeldt-Jakob disease
Creutzfeldt-Jakob disease (CJD) is a transmissible spongiform encephalopathy that results in rapidly progressive dementia and death usually within a year from onset. The vast majority are sporadic, but familial and acquired forms are occasionally encountered.
On imaging, it classically manifest...
Article
Gadolinium contrast agents
Gadolinium-based contrast media (GBCM), gadolinium-based contrast agents (GBCAs), or simply gadolinium contrast agents, are molecular complexes containing the rare earth metal gadolinium, chelated to a carrier ligand. They are a type of paramagnetic contrast agent, which are the primary class of...
Article
Adrenal adenoma
Adrenal adenomas (alternative plural: adenomata) are the most common adrenal lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adr...
Article
Sacrococcygeal teratoma
Sacrococcygeal teratoma refers to a teratoma arising in the sacrococcygeal region. The coccyx is almost always involved 6.
Epidemiology
It is the most common congenital tumor in fetus 11 and neonate 3. The incidence is estimated at ~1:35,000-40,000. There is a recognized female predilection wi...
Article
Double doughnut sign
The double doughnut sign, or double-doughnut sign, is a radiological sign described in MRI of viral encephalitis, typically due to dengue encephalitis.
The double doughnut sign refers to a pattern of signal changes in the bilateral thalami that have a doughnut-like appearance 1-4. This sign is ...
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