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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

39 results found
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14-3-3 protein

14-3-3 proteins are found in the cerebrospinal fluid (CSF), and are currently used to help identify patients with sporadic Creutzfeldt-Jakob disease (sCJD).  Seven distinct 14-3-3 proteins have been found in humans. In diagnosing sCJD, the sensitivity of 14-3-3 protein is 92% and its specifici...
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1p19q codeletion

1p19q codeletion stands for the combined loss of the short arm chromosome 1 (i.e. 1p) and the long arm of chromosome 19 (19q) and is recognised as a genetic marker predictive of therapeutic response to both chemotherapy and combined chemoradiotherapy and overall longer survival in patients with ...
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2-hydroxyglutarate

2-hydroxyglutarate is a metabolite that accumulates in the brains of patients with IDH-1 mutated (IDH-1 positive) brain tumours, particularly diffuse low-grade gliomas. Although not in widespread clinical use, it is likely that 2-hydroxyglutarate, which resonates at 2.25 ppm, will be able to be ...
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Alzheimer type I glia

Alzheimer type I glia are a type of glial cell. They are large multinucleated astrocytes encountered in glial tumours and progressive multifocal leukoencephalopathy (PML) 1. 
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Alzheimer type II glia

Alzheimer type II glia are a type of glial cell. They are a pathological reactive astrocyte seen in the brain, unrelated to Alzheimer disease. They are seen most frequently in Wilson disease, but also in other systemic metabolic disorders, particularly those with elevated ammonia levels, typical...
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Astrocytes

Astrocytes are cells of the central nervous system which act as both physical and physiological support for the neurones that are embedded between them. They are particularly abundant in the grey matter, where they are the most abundant glial cells 1. They are highly branched and contribute to ...
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Choristoma

A choristoma is simply a collection of microscopically normal cells or tissues in an abnormal location. This is different to a hamartoma which is derived only from local tissues. Examples include: adrenal choristoma (myelolipoma) nasopharyngeal choristoma facial nerve choristoma optic nerve...
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Choroidal epithelial cells

Choroidal epithelial cells are one of the three types of ependymal cells, themselves a type of glial cell. They cover the surface of the choroid plexus and produce cerebrospinal fluid (CSF). 1. 
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Cowdry bodies

Cowdry bodies are neuronal intranuclear inclusions seen in Herpes simplex virus infections 1. Pathology Cowdry bodies are in fact fixation artifacts and not directly the result of the intracellular virus 2. 
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Ependymal cells

Ependymal cells are one of the four main types of glial cells, and themselves encompass three types of cells 1:  ependymocytes: line the ventricles of the brain and central canal of the spinal cord tanycytes: line the floor of the third ventricle choroidal epithelial cells: line the surface o...
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Ependymal rosettes (ependymoma)

Ependymal rosettes correspond to a histologic architectural pattern that very characteristic of ependymomas, as tumour cells form structures similar to the lining of normal ventricles. They are characterised by a halo or spoke-wheel arrangement of tumour cells surrounding an empty central tubule...
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Ependymocytes

Ependymocytes are one of the three types of ependymal cells, which in turn are one of the four principles types of glial cells, and are found lining the ventricular system of the brain and the central canal of the spinal cord 1.  They do not form a water-tight barrier between the cerebrospinal ...
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Epithelial membrane antigen (EMA)

Epithelial membrane antigen (EMA) is a commonly used target for immunohistochemisty, found on the surface of many epithelial cells and thus present in a wide variety of tumours. It also is sometimes seen within the cytoplasm of cells (e.g. perinuclear dot in ependymomas). 
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Flexner-Wintersteiner rosette

The presence of Flexner-Wintersteiner rosette is characteristic for retinoblastoma but is also seen in pineoblastoma and medulloepitheliomas. 
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Glial cells

Glial cells, or neuroglia, are cells that surround the neurones of the central nervous system embedded between them, providing both structural and physiological support 1-3.  Together they account for almost half of the total mass 1 and 90% of all cells of the central nervous system 3. These num...
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Glial fibrillary acid protein (GFAP)

Glial fibrillary acid protein (GFAP) is a commonly used target for immunohistochemistry and is positive in many glial cells and tumours of glial origin. GFAP is the building block for intermediate filaments which are abundant in the cytoplasms particularly of astrocytes. 
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Gliosis

Gliosis is the focal proliferation of glial cells in the CNS in response to insult. By strict definition, gliosis is not synonymous with encephalomalacia which is the end result of liquefactive necrosis of brain parenchyma following an insult. Radiologically they share similar features and the d...
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Homer Wright rosettes

Homer Wright rosettes are differentiated tumour cells grouped around a central region containing neuropil (therefore its association with tumors of neuronal origin). Pathology Examples of tumours where these can be seen include: medulloblastoma (the presence of Homer Wright rosettes in a post...
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Intracranial arteries

Intracranial arteries have unique structure when compared to extracranial vessels of similar size: see general histology of blood vessels entry. Proximal larger arteries The proximal arteries, arising from the internal carotid and vertebral arteries have differing distribution of elastic fiber...
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Isocitrate dehydrogenase

Isocitrate dehydrogenase (IDH) gene mutations are increasingly being recognised as key genetic prognostic markers for diffuse gliomas, and have been included in a recent (2016) update of diffuse astrocytomas in the WHO classification of brain tumours 7. Somatic mutations of IDH result in enchond...
Article

John Cunningham virus

John Cunningham virus (but universally called the JC virus) is a ubiquitous double-stranded DNA virus of the polyomaviridae family 1. It is the aetiological agent of progressive multifocal leukoencephalopathy (PML). Cases of cerebellar neuronal involvement (JC virus granule cell neuronopathy) as...
Article

Lipohyalinosis

Lipohyalinosis is a disease affecting the small cerebral arteries associated with lacunar infarction and deep white matter changes related to small vessel chronic ischaemia. Pathology The histopathological landmarks of lipohyalinosis are irregular fibrosis and hyaline of small cerebral arterie...
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Liquefactive necrosis

Liquefactive necrosis is a form of necrosis where there is transformation of the tissue into a liquid viscous mass. Pathology In liquefactive necrosis, the affected cell is completely digested by hydrolytic enzymes leading to a soft, circumscribed lesion which can consist of fluid with remains...
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Microglia

Microglia is one of the four types of glial cell and are the central nervous system equivalent of monocyte-macrophage system 1,2. During health, they are essentially inactive with small cell bodies and numerous processes extending throughout the local parenchyma 1,2. When presented a condition w...
Article

Myoinositol peak

Myoinositol is one of the compounds images with MR spectroscopy (MRS) at both 1.5 T and 3 T and is seen to resonate at 3.5 ppm chemical shift (right of the choline peak).  Myoinositol is a precursor of both phosphatidylinositol (the major inositol-containing phospholipid) and of phosphatidylino...
Article

Neuritic plaques

Neuritic plaques (also known as senile plaques) are pathological extracellular aggregates formed around a core of amyloid β peptide and are a hallmark of Alzheimer's disease.  They should not be confused with neurofibrillary tangles which are intracytoplasmic. Pathology Neuritic plaques are e...
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Neurofibrillary tangles

Neurofibrillary tangles (NFTs) are abnormal cytoplasmic accumulations of tau proteins, found in neuronal and glial cells of the central nervous system. They are responsible for a number of neurodegenerative diseases (collectively known as tauopathies) including 1: progressive supranuclear palsy...
Article

Neurone

Neurones are cells of the central nervous system, located within the grey matter, and responsible for all neurological functions of the brain.  Structure Neurones vary in morphology and size substantially, but all share a number of features 1: a cell body nucleus perikaryon: cytoplasm surro...
Article

Oligodendrocytes

Oligodendrocytes are one of the four principles types of glial cells and are the central nervous system equivalent of the Schwann cells found peripherally. They wrap the neurones of the brain and spinal cord with myelin 1.  See also oligodendroglioma
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Perivascular pseudorosettes (ependymoma)

Perivascular pseudorosettes are a common histologic feature of central nervous system ependymomas. They represent sections through papillary structures composed of tumour cells arranged radially around a central vessel. Between the central vessel and the tumour cells is a relatively microscopica...
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Pick bodies

Pick bodies are intracytoplasmic spherical inclusions found in Pick's disease. They are composed of tau fibrils (thus Pick's disease is a tauopathy) arranged in a disorderly array 1. Although tau protein is a major component a number of other protein products are present, including ubiquitin and...
Article

Pseudocyst

A pseudocyst is an abnormal fluid-filled cavity which is not lined by epithelium.  It is this fact that distinguishes it pathologically from a cyst, which is lined by epithelium. Examples of pseudocysts are: pancreatic pseudocyst pulmonary pseudocyst pseudocysts of the germinal matrix
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Rosenthal fibres

Rosenthal fibres are astrocytic cytoplasmic inclusions, typically found in areas of longstanding gliosis. These elongated or "corkscrew" structures occur within astrocytic processes and are brightly eosinophilic (stain bright pink on the H&E stain) 1-3. They represent astrocytic processes swolle...
Article

Tanycytes

Tanycytes are one of the three types of ependymal cells, themselves a type of glial cell. They are found lining the floor of the third ventricle and the median eminence of the hypothalamus 1.   It is believed that these specialised cells are involved in the feedback mechanisms on the anterior p...
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Tissue tropism

Tissue tropism is a phenomenon by which certain host tissues preferentially support the growth and proliferation of pathogens. This concept is central to the radiological evaluation of infectious disease.  Pathology As infections that display tissue tropism will thrive in certain tissue locati...
Article

Verocay bodies

Verocay bodies are a histological feature of schwannomas and represent a particular growth pattern of Antoni type A pattern in which tumour cells form alternating parallel rows of nuclear palisades separated by regions of acellularity 1. 
Article

Vitamin B1

Vitamin B1 (thiamine) is a water soluble vitamin that is an important coenzyme for two reactions in the citric acid cycle (Kreb cycle). It therefore is vital for cellular ATP production, particularly in the central nervous system. Related pathology Pathological manifestations only occur with t...
Article

Vitamin B3

Vitamin B3 (niacin or nicotinic acid) is a water-soluble vitamin that is an important part of the coenzyme nicotinamide adenine dinucleotide (NAD+) which is involved in many reactions of cellular metabolism. Related pathology Pathological manifestations occur in niacin deficiency, which is kno...
Article

Vitamin B9

Vitamin B9 (folate or folic acid) is a water-soluble vitamin that is vital for the synthesis of several amino acids, the purines adenosine and guanine and the pyrimidine thymine (three of the four nucleotide bases and hence critical for the synthesis of nucleic acids.) The antimicrobial drug cl...

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