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.

16,857 results found
Article

Unilateral hypertransradiant hemithorax (mnemonic)

Unilateral hypertransradiancy is the correct term for the chest radiograph appearance of increased blackness affecting one lung. Hyperlucency is a commonly used alternative but is inaccurate; the chest is not penetrated by light! A logical approach begins by checking for: technical factors p...
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Aortic nipple

Aortic nipple is the name given to the chest radiography appearance of the left superior intercostal vein as it courses over the aortic arch. This small convexity is seen in less than 10% of PA chest x-rays. The caliber of the vein normally changes with intrathoracic pressure and patient positio...
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Ataxia-telangiectasia

Ataxia-telangiectasia, also known as Louis-Bar syndrome, is a rare multisystem autosomal recessive disorder, sometimes classified as a phakomatosis. It is characterized by multiple telangiectasias, cerebellar ataxia, pulmonary infections, and immunodeficiency.  On brain imaging, it usually demo...
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Cerebral hyperperfusion syndrome

Cerebral hyperperfusion syndrome is a rare complication seen after treatment of long-standing severe carotid stenosis by carotid endarterectomy or carotid artery stenting. It is believed to be the result of failure of normal cerebral blood flow autoregulation.  Terminology Cerebral hyperperfus...
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Hartmann procedure

Hartmann procedure, a.k.a. proctosigmoidectomy, is an operation in which the sigmoid colon is resected and the distal colon brought out as a colostomy in the left iliac fossa. The remnant rectum stump is sewn shut. It is a quick and straightforward intervention and currently finds most favor in ...
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Benjamin Felson

Benjamin "Benny" Felson (1913-1988) was a renowned Cincinnati chest radiologist who coined or popularized several of the most commonly-used terms in the everyday parlance of the English-speaking radiology community.   Early life Benjamin Felson was born in Newport, Kentucky on 21 October 1913 ...
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Endometriosis

Endometriosis is a common, chronic gynecological condition defined as the presence of functional endometrial glands and stroma-like lesions outside the uterus. It manifests in three ways: superficial (peritoneal) disease, ovarian disease (endometriomas), and deep endometriosis. Endometriosis is...
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Calcific tendinitis

Calcific tendinitis, also known as calcific tendinopathy or tendonitis, is a self-limiting condition due to the deposition of calcium hydroxyapatite within tendons, usually of the rotator cuff. It is a common presentation of hydroxyapatite crystal deposition disease (HADD).  Epidemiology Typic...
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Hydroxyapatite deposition disease

Hydroxyapatite crystal deposition disease (HADD) or calcium apatite deposition disease (CADD) is a disease of uncertain etiology characterized by periarticular and intra-articular calcium deposits. The shoulder is the most frequently involved site with classic calcific tendinitis presentation. ...
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Rotator cuff calcific tendinitis barbotage

Rotator cuff calcific tendonitis can be treated with various techniques including ultrasound-guided barbotage, which is also known as ultrasound-guided needling and lavage. It is often performed in conjunction with a subacromial bursal injection. Alternative treatments include extracorporeal sho...
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Central neurocytoma

Central neurocytomas are WHO grade 2 neuroepithelial intraventricular tumors with fairly characteristic imaging features, appearing as heterogeneous masses of variable size and enhancement within the lateral ventricle, typically attached to the septum pellucidum. They are typically seen in young...
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Supraclavicular triangle

The supraclavicular triangle is one of the paired triangles in the posterior triangle of the neck. The triangles of the neck are surgically focussed, first described from early dissection-based anatomical studies which predated cross-sectional anatomical description based on imaging (see deep sp...
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Iliolumbar ligament

The iliolumbar ligament is a strong band of connective tissue which courses from the transverse process of L5 (in over 96% of cases) to the posterior iliac wing and crest of the ilium. It functions to maintain the alignment of L5 on the sacrum during various movements 1,2. It is an important la...
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Skull

The skull (TA: cranium) is the superior-most part of the human skeleton and houses the brain and includes the skeletal elements of the face. It consists of numerous bones connected to each other by sutures which renders them immobile. Terminology Variability in which bones to include and how ...
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Melioidosis

Melioidosis is an infectious disease caused by the bacterium Burkholderia pseudomallei (previously known as Pseudomonas pseudomallei) and is a multisystem disorder which may affect the lungs, brain, visceral organs, or musculoskeletal system. Epidemiology Melioidosis is a disease of the monsoo...
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Rule of 4 of the brainstem

The rule of 4 of the brainstem elegantly simplifies and explains the anatomy of the brainstem and the basis for various brainstem stroke syndromes. This article summarizes the original four rules 1-3, associated important clinical deficits, important exceptions, and provides two examples of thei...
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Cobalt

Cobalt (chemical symbol Co) is an essential trace element. Its most important function in humans is as the active metal atomic center of vitamin B12. Chemistry Basic chemistry Cobalt is a shiny grey-silvery transition metal with an atomic number 27 and an atomic weight of 58.93 Daltons (Da). ...
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Coxa vara

Coxa vara describes a hip deformity where the femoral neck-shaft angle is decreased, usually defined as <120°. Pathology It can be congenital or acquired. The common mechanism in congenital cases is a failure of the medial growth of the physeal plate 3.   Etiology The etiology of coxa vara w...
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Paget disease (bone)

Paget disease of the bone is a common, chronic metabolic bone disorder characterized by excessive abnormal bone remodeling. The classically described radiological appearances are expanded bone with a coarsened trabecular pattern. The pelvis, spine, skull, and proximal long bones are most frequen...
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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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