Articles

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16,906 results found
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Soft tissue abscess

Soft tissue abscesses are focal or localized collections of pus caused by an immune response to pathogenic microorganisms. They are surrounded by a peripheral rim or abscess membrane and can be found within the soft tissues in any body part 1. Soft tissue abscesses include subcutaneous abscesse...
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Penumbra sign (intraosseous abscess)

In musculoskeletal radiology, the penumbra sign represents a rim of vascularized granulation tissue surrounding an intraosseous abscess cavity, with a higher T1 signal intensity than the cavity itself 1. This finding is a specific (~98%) but relatively insensitive (~55%) sign to distinguish suba...
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Normal pressure hydrocephalus

Normal pressure hydrocephalus remains a controversial entity with often ambiguous imaging findings. It is classically characterized by the triad of gait apraxia/ataxia, urinary incontinence, and cognitive impairment, although not all patients with the condition have all three 31. On imaging, it...
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Persistent carotid-vertebrobasilar anastomoses

The persistent carotid-vertebrobasilar anastomoses are variant anatomical arterial communications between the anterior and posterior circulations due to abnormal embryological development of the vertebrobasilar system. They are named, with the exception of the proatlantal artery, using the crani...
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Sclerotic bone metastases

Sclerotic or osteoblastic bone metastases are distant tumor deposits of a primary tumor within bone characterized by new bone deposition or new bone formation. Epidemiology Bone metastases are the most common bone malignancy, with sclerotic bone metastases being less common than lytic bone met...
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Lytic bone metastases

Lytic bone (osteolytic) metastases are distant tumor deposits of a primary tumor within bone characterized by a loss of bone with the destruction of the bone matrix. Epidemiology Lytic bone metastases are more common than sclerotic bone metastases. Diagnosis The diagnosis is usually establis...
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Mixed lytic and sclerotic bone metastases

Mixed lytic and sclerotic bone (osteolytic and osteoblastic) metastases refer to metastatic bone disease with both sclerotic and lytic bone metastases or bone metastases with both components. Diagnosis The diagnosis is established by proof of sclerotic and lytic bone metastases of one primary ...
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Squamous cell carcinoma of the penis

Squamous cell carcinoma (SCC) of the penis is an uncommon condition that often presents at an advanced stage. Imaging is more often used for staging than for the initial diagnosis. It is the commonest histological subtype of penile cancer. Epidemiology Penile cancer is a relatively infrequent ...
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Monochorionic monoamniotic twin pregnancy

A monochorionic monoamniotic (MCMA) twin pregnancy is a subtype of monozygotic twin pregnancy. These fetuses share a single chorionic sac, a single amniotic sac, and, in general, a single yolk sac.  Epidemiology It accounts for the minority (~5%) of monozygotic twin pregnancies and ~1-2% of al...
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Lipomyelocele

Lipomyelocele, also known as lipomyeloschisis, is one of the most common closed spinal dysraphisms. It is most commonly encountered in the thoracolumbar region and usually presents as a fatty subcutaneous mass. It should not be confused with myeloschisis which is a severe form of open spinal dy...
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Spinal instability neoplastic score (SINS)

The spinal instability neoplastic score (SINS) helps to assess tumor-related instability of the vertebral column. It has been shown to be useful in guiding the mobilization or operative management of patients with neoplastic spinal disease and correlates with patient-reported outcomes 1-4. Stud...
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Spinal dysraphism

Spinal dysraphisms refer to a broad group of malformations affecting the spine and/or surrounding structures in the dorsum of the embryo. They are a form of neural tube defect. Terminology The term dysraphism implies that the cause of the abnormality is due to anomalous midline fusion and shou...
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Spatial compounding (ultrasound)

Spatial compounding is an advanced ultrasound technique that utilizes multiple angles of insonation to create a single averaged image 1. Clinical applications The advantages of spatial compounding are that angle dependent artefacts are reduced, curved surfaces appear more continuous and backgr...
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Esophageal stricture

Esophageal stricture refers to any persistent intrinsic narrowing of the esophagus.  Terminology The term peptic stricture refers specifically to those benign esophageal strictures caused by chronic acid reflux, although some - incorrectly - use it more loosely to refer to any benign esophagea...
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Schatzki ring

A Schatzki ring, also called a Schatzki-Gary ring, is a symptomatic, narrow esophageal B-ring occurring in the distal esophagus and usually associated with a hiatus hernia.  Epidemiology Relatively common, lower esophageal rings are found in ~6-14% of oesophagrams 9.  Associations More than ...
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Salter-Harris classification

The Salter-Harris classification was proposed by Salter and Harris in 1963 1 and, at the time of writing (January 2023) remains the most widely used system for describing physeal fractures.  Classification Conveniently the Salter-Harris types can be remembered by the mnemonic SALTR. type I s...
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Percutaneous nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is a surgical procedure for the extraction of large renal calculi. It is usually performed in the operating theater either by a urologist or combined urologist-radiologist team. Indication PCNL is used to destroy and remove renal calculi, typically over 2 cm...
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Autoimmune glial fibrillary acid protein (GFAP) astrocytopathy

Autoimmune glial fibrillary acid protein (GFAP) astrocytopathy, or simply GFAP astrocytopathy, is a rare inflammatory central nervous system (CNS) disorder. Epidemiology Given the rarity of the condition, epidemiological data pertaining to autoimmune GFAP astrocytopathy are not well establishe...
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Alexander disease

Alexander disease, also known as fibrinoid leukodystrophy, is a rare fatal leukodystrophy. Usually clinically evident in the infantile period, neonatal, juvenile, and adult variants are recognized. As with many diseases with a variable age of presentation, the earlier it manifests the more fulmi...
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External auditory canal cholesteatoma

External auditory canal cholesteatomas are a rare subtype of acquired cholesteatoma. Epidemiology The external acoustic canal is a rare location for a cholesteatoma with an estimated incidence of around 1.2 per 1,000 new otological patients ref. The overall incidence rate in one large study wa...

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