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.
16,861 results found
Article
Cardiac amyloidosis
Cardiac amyloidosis (plural: amyloidoses) is a significant source of morbidity among patients with systemic amyloidosis and is the most common cause of restrictive cardiomyopathy outside the tropics.
Pathology
Amyloidosis represents the extracellular deposition of insoluble fibrillar proteinac...
Article
Niacin (vitamin B3) excess
In general taking large doses of water-soluble vitamins has not been found to have a deleterious clinical effect. However niacin (vitamin B3) excess can be problematic, usually when greater than 100 mg niacin is taken per day. To put this in context the recommended daily allowance (RDA) in the U...
Article
Hypervitaminosis D
Hypervitaminosis D (also known as vitamin D toxicity (VDT)) is very rare, and is usually secondary to exogenous administration of megadoses of vitamin D over long periods. Clinically it manifests as the clinical sequelae of chronic hypercalcemia.
Epidemiology
Incidence is unknown, however inte...
Article
Glucagon
Glucagon is a polypeptide hormone central to the regulation of glucose homeostasis, acting as an antagonist to insulin. In imaging, it is used as an antiperistaltic agent in GI studies, although its clinical efficacy is controversial.
Structure
Glucagon is a 29-amino acid polypeptide hormone ...
Article
Pulmonary infarction
Pulmonary infarction is one of the key complications of pulmonary embolism (PE).
Epidemiology
Pulmonary infarction occurs in the minority (10-15%) of patients with PE 1. Although in a necropsy study of those with lethal PE, 60% of cases developed infarction 2.
Historically it was thought tha...
Article
Transthyretin amyloidosis
Transthyretin (ATTR) amyloidosis is a form of systemic amyloidosis characterized by the misfolding, aggregation and deposition of transthyretin-related (TTR) protein in various organs 1-6. This can occur in the following two forms namely in the setting of a genetically normal transthyretin-relat...
Article
Nasopharyngeal carcinoma
Nasopharyngeal carcinomas (NPC) are the most common primary malignancy of the nasopharynx. They are of squamous cell origin. Some types are strongly associated with the Epstein-Barr virus (EBV).
Epidemiology
Nasopharyngeal carcinoma accounts for ~70% of all primary malignancies of the nasophar...
Article
COVID-19
For a quick reference guide, please see our COVID-19 summary article.
COVID-19 (coronavirus disease-2019) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a strain of coronavirus. The first cases were seen in Wuhan, China, in December 2019 before ...
Article
Articular-sided rotator cuff tear
Articular-sided rotator cuff tears are partial-thickness rotator cuff tears extending from the articular side into the rotator cuff.
Epidemiology
Articular-sided rotator cuff tears commonly occur in athletes with overhead activity 1.
They are more common than bursal-sided tears and most commo...
Article
CT head (protocol)
CT head, also known as CT brain, refers to a computed tomography (CT) examination of the brain and surrounding cranial structures. It is most commonly performed as a non-contrast study, but the addition of a contrast-enhanced phase is performed for some indications.
This article covers non-cont...
Article
Occipital vertebra
Occipital vertebrae are rare anatomical variants that result from incomplete or aberrant fusion of occipital bone ossification centers. There is a broad spectrum of occipital vertebrae, the more common variants include:
third condyle (condylus tertius)
basilar process
prebasioccipital arch
p...
Article
Rotator cuff repair
Rotator cuff repair involves suturing the torn tendon(s) back onto its attachment to the humerus and may be performed either via arthroscopy or open surgery, using sutures and/or bone anchors.
Procedure
a suture is passed across the long limb of the tear from side to side, using a special inst...
Article
Angiolipoma
Angiolipomas are rare soft tissue tumors composed of mature adipocytes and vessels. They most commonly arise in the subcutaneous tissues of the extremities.
Please refer to the epidural (spinal) angiolipoma article for a specific discussion. The remainder of this article describes the general f...
Article
Candida esophagitis
Candida esophagitis is the most common cause of infectious esophagitis that commonly affects immunocompromised patients. On imaging, it is characterized by irregular plaque-like lesions separated by normal mucosa and small (<1 cm) ulcers, which are assessed on esophagogram studies.
Epidemiolo...
Article
F-18 DOPA
F-18 DOPA (3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine) is a PET radiotracer primarily used in the evaluation of neuropsychiatric diseases, movement disorders, and brain malignancies 1.
Production
L-DOPA is the non-proteinogenic amino acid precursor to dopamine, with F-18 DOPA usually being s...
Article
Focal nodular hyperplasia
Focal nodular hyperplasia (FNH) is a regenerative mass lesion of the liver and the second most common benign liver lesion (the most common is a hemangioma). Many focal nodular hyperplasias have characteristic radiographic features on multimodality imaging, but some lesions may be atypical in app...
Article
Modality
Modality is the term used in radiology to refer to one form of imaging, e.g. CT. It is often used in the plural form, e.g. "various modalities can be employed to evaluate this liver lesion."
More generally, in clinical medicine, the term 'modality' refers to different types of procedures and th...
Article
Contrast-enhanced ultrasound
Contrast-enhanced ultrasound (CEUS) involves the administration of intravenous contrast agents consisting of microbubbles/nanobubbles of gas.
Clinical applications
liver
hepatic metastasis
cystadenoma/cystadenocarcinoma
cholangiocarcinoma
hepatocellular carcinoma
hepatic adenoma
focal no...
Article
Electrical impedance tomography
Electrical impedance tomography (EIT) is a type of imaging based on sending small amounts of electrical current across tissue (when used for medical imaging) and measuring conductivity.
Terminology
There are several ways in which the EIT signal can be generated and processed, and these are oft...
Article
Placental site trophoblastic tumor
Placental site trophoblastic tumors (PSTT) are rare and one of the least common (~0.2% 7) forms of gestational trophoblastic disease.
Epidemiology
Placental site trophoblastic tumors typically occur in women of reproductive age with an average age of ~30 years. They may occur after a normal pr...
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