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.

16,914 results
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Cauda equina syndrome

Cauda equina syndrome (CES) is considered an incomplete cord syndrome, even though it occurs below the conus. Cauda equina syndrome refers to a collection of symptoms and signs that result from severe compression of the descending lumbar and sacral nerve roots. It is most commonly caused by an a...
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Crohn's disease

Crohn's 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 diagn...
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Medical abbreviations and acronyms (P)

This article contains a list of commonly used medical abbreviations and acronyms that start with the letter P and may be encountered in medicine and radiology (please keep the main list and any sublists in alphabetic order). A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R ...
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Neurocysticercosis

Neurocysticercosis is caused by the CNS infection with the pork tapeworm Taenia solium, which is endemic in most low-income countries where pigs are raised. This form of cysticercosis is a relevant cause of seizures in endemic areas. Epidemiology The disease is endemic in Central and South Ame...
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Pyloric stenosis

Hypertrophic pyloric stenosis (HPS) refers to the idiopathic thickening of gastric py­loric musculature which then results in progressive gastric outlet obstruction. Epidemiology Pyloric stenosis is relatively common, with an incidence of approximately 2-5 per 1000 births, and a male predilect...
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Gastroduodenal artery

The gastroduodenal artery (GDA) is a terminal branch of the common hepatic artery that mainly supplies the pylorus of the stomach, proximal duodenum, and the head of the pancreas. Due to its proximity to the posterior wall of the first part of the duodenum, the gastroduodenal artery is one of th...
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Primary cutaneous melanoma

Primary cutaneous melanoma is the most common subtype of melanoma, a malignant neoplasm that arises from melanocytes. Melanocytes predominantly occur in the basal layer of the epidermis but do occur elsewhere in the body. Primary cutaneous melanoma is by far the most common type of primary melan...
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Interarterial course of the right coronary artery

Interarterial course of the right coronary artery may occur if the right coronary artery (RCA) has an aberrant origin from the left coronary sinus. The interarterial course occurs because the artery passes between the ascending aorta and the pulmonary trunk 1-3. It is an uncommon anatomic varia...
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Caroticocavernous fistula

Caroticocavernous fistulas represent abnormal communication between the carotid circulation and the cavernous sinus. They can be classified as direct or indirect which are separate conditions with different etiologies.   Epidemiology Direct caroticocavernous fistulas are often secondary to tra...
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Anomalous aortic origin of coronary artery

Anomalous aortic origin of coronary artery (AAOCA) refers to a congenital coronary artery anomaly in which a coronary artery arises from a different coronary sinus. Terminology Anomalous origin of the coronary artery arising from the opposite sinus (ACAOS) is a narrower definition and refers t...
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Sellar spine

Sellar spine corresponds to a rare variant of the sella turcica bony structure characterized by a mid-line spur that projects anteriorly from the dorsum sellae. It has no clinical significance, but it may be confused with a hypophyseal nodule (e.g. microadenoma) on low-resolution MRI images, esp...
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k-space

k-space is an abstract concept and refers to a data matrix containing the raw MRI data. This data is subjected to mathematical function or formula called a transform to generate the final image. A discrete Fourier or fast Fourier transform 1-3 is generally used, though other transforms such as t...
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Pituitary carcinoma

Pituitary carcinomas or metastatic PitNET are rare tumors that are histologically indistinguishable from pituitary adenomas (PitNET) on imaging, defined only by the presence of central nervous system or systemic metastases. Terminology In the 5th edition of the WHO classification of CNS tumors...
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Pituitary gland

The pituitary gland (a.k.a. hypophysis cerebri), together with its connections to the hypothalamus, acts as the main endocrine interface between the central nervous system and the rest of the body.  Gross anatomy The pituitary gland sits atop the base of the skull in a concavity within the sph...
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Lunotriquetral coalition

A lunotriquetral coalition, also known as lunotriquetral fusion or synostosis, is a type of carpal coalition and represents a congenital lack of separation of the lunate and triquetral bones of the carpus.  Terminology The term coalition is preferred over fusion for congenital coalitions, as d...
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Pituitary macroadenoma

Pituitary macroadenomas are the most common suprasellar mass in adults, and responsible for the majority of transsphenoidal hypophysectomies. They are defined as pituitary adenomas greater than 10 mm in size and are approximately twice as common as pituitary microadenomas.  On imaging, they usu...
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Grey matter

The grey matter is the substance of the brain and spinal cord that contains the neuronal cell bodies of the central nervous system. Within the cerebrum the two main locations of grey matter are on the surface of the gyri (the cortical grey matter) and the nuclei of the basal ganglia. The brains...
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Velocity encoding

Velocity encoding or Venc is referred to as an operator-controlled parameter for the determination of the maximum velocity within a velocity-encoded phase contrast imaging study. Usage Velocity-encoding (Venc) gradients are used to generate a phase shift in magnetic resonance phase contrast im...
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Chipmunk sign (brainstem)

The chipmunk sign refers to the MRI appearance of the medulla in some patients with leukodystrophies, particularly Alexander disease. The same appearance has been described in adult polyglucosan body disease, vanishing white matter disease, Pelizaeus-Merzbacher disease, 4H syndrome, and adult-on...
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Mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE)

Mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE) is a histopathological entity primarily associated with drug-resistant frontal lobe epilepsy. MOGHE is characterized by a distinct histological phenotype that includes blurred gray-white matter bound...

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