Articles

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16,914 results
Article

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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Modified Dallas discographic classification of intervertebral disc radial tears

The modified Dallas classification describes the discography appearance of radial annular tears of the intervertebral disc. Classification grade 0: contrast remains in the nucleus pulposus grade 1: contrast leaks into the inner 1/3 of the annulus fibrosus grade 2: contrast leaks into the mid...
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Anterior superior aortic recess

The anterior superior aortic recess is one of the variable invaginations of the superior aortic recess and is located anterior to the ascending aorta (mostly towards the left) 1-4. It can sometimes include aortopulmonary window region 1. Clinical importance It may occasionally mimic mediastina...
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Sinonasal glomangiopericytoma

Glomangiopericytomas (GPC), also known as sinonasal-type hemangiopericytomas, are rare vascular tumors that typically arise in the nasal cavity and paranasal sinuses characterized by a perivascular myoid pattern 1. Terminology  Glomangiopericytomas (GPCs) are often referred to as sinonasal hem...
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Mesenteric cyst

Mesenteric cysts are a very rare cause of abdominal pain and have a wide range of underlying causes.  Terminology The term "mesenteric cyst" is considered a descriptive of the location and gross appearance of "any cyst" arising in the mesentery 8. Epidemiology Mesenteric cysts are rare, with...
Article

Basilar invagination

Basilar invagination, also called basilar impression, is a congenital or acquired craniocervical junction abnormality where the tip of the odontoid process projects above the foramen magnum.  Terminology The following terms are often used interchangeably because they describe upwards migration...
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Airway foreign bodies in children

Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common. Epidemiology Children under the age of four years have an increased risk of foreign body (FB) aspiration, with a slight male predominance 1.  C...
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Mycetoma (soft-tissue)

Mycetoma refers to a chronic and progressively destructive granulomatous disease within the soft tissues. The defining clinical triad comprises of a: localized mass-like soft tissue injury with draining sinuses that discharge grains of contagious material It is one of the "neglected tropical...
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Xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis and represents a chronic granulomatous disease resulting in a non-functioning kidney. Radiographic features are usually specific. Epidemiology Xanthogranulomatous pyelonephritis is seen essentially in all age gro...
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Fat-containing renal lesions

There are numerous fat-containing renal lesions, including: renal angiomyolipoma renal cell carcinoma (often has calcifications when contains macroscopic fat) Wilms tumor (most common pediatric renal mass) renal oncocytoma renal or perirenal lipoma/liposarcoma Non-mass lesions may also occ...
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Acromioclavicular joint injury

Acromioclavicular joint injuries, commonly shortened to ACJ injuries, are characterized by damage to the acromioclavicular joint and surrounding structures. Almost invariably traumatic in etiology, they range in severity from a mild sprain to complete disruption. Epidemiology Acromioclavicular...
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Post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD), also referred as post-transplant lymphoproliferation disorder, represents a variety of conditions ranging from lymphoid hyperplasia to malignancy, included in the WHO classification of haematolymphoid tumors under "lymphoid proliferations and ...
Article

Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell, non-familial multisystemic histiocytosis, with widespread manifestations and of highly variable severity. The most common presenting symptom is bone pain. Epidemiology Erdheim-Chester disease is a rare, non-inherited disease of middl...

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