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.

2,020 results found
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Dorsal root ganglion

The dorsal root ganglia are an enlargement of the dorsal root of spinal nerves representing the cell bodies of the primary somatosensory neurons. Gross anatomy Each dorsal root ganglion is oval and proportional in size to its related root. They are usually found just distal to the intervertebr...
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Dorsal thoracic arachnoid web

Dorsal thoracic arachnoid web is a cause of focal thoracic cord distortion with resulting neurological dysfunction.  Clinical presentation Due to the limited number of reported cases the incidence of this condition may well be under-recognised. The cases reported have a variety of signs and sy...
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Double density sign (berry aneurysm)

Double density sign of berry aneurysms refers to the angiographic appearance of a small intracranial aneurysm projecting in front or behind a vessel of similar calibre. As such, the border of the aneurysm cannot easily be seen, but the extra contrast within it can be seen as a rounded area of in...
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Double density sign (osteoid osteoma)

The double density sign, also sometimes clumsily referred to as the hotter spot within hot area sign, is a bone scan sign of an osteoid osteoma. It refers to a central focus of intense uptake (the nidus) within a surrounding lower, but nonetheless increased uptake, rim. See also double densit...
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Double inversion recovery sequence

Double inversion recovery (DIR) is a MRI pulse sequence which suppresses signal from the CSF as well as from the white matter and hence enhances any inflammatory lesion. To obtain such sequence in 3T MRI scanner, two inversion times are required. TI1 which is used for suppression of CSF and usu...
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Double panda sign

The double panda sign refers to the combination of the face of the giant panda and face of the miniature panda (cub of the giant panda) seen on T2 weighted images of midbrain and pons respectively in Wilson disease. The midbrain face of the giant panda sign consists of normal intensity of red n...
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Down syndrome

Down syndrome (or trisomy 21) is the most common trisomy and also the commonest chromosomal disorder. It is a major cause of intellectual disability, and also has numerous multi-system manifestations. Epidemiology According to the world health organisation (WHO), the approximate worldwide inci...
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Dual rim sign

The dual or double rim sign is seen on MRI in approximately 75% of cerebral abscesses and is helpful in distinguishing an abscess from a glioblastoma (GBM).  On both susceptibility weighted imaging (SWI) and T2WI it consists of two concentric rims surrounding the abscess cavity, outer one of wh...
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Duane syndrome

Duane syndrome, also known as Duane retraction syndrome, is a rare congenital disease characterised by non-progressive strabismus. It is caused by a variable degree of abnormal development of one or both 6th cranial nerves (CN VI). Epidemiology It presents during childhood and it accounts for ...
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Dumbbell appearance of spinal tumours

The dumbbell appearance of spinal tumours refers to a tumour which has both a component within the canal and a component in the paravertebral space contiguous with each other via a thinner tumour component traversing the neural exit foramen. The appearance can be seen in: spinal nerve sheath t...
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Duplicated middle cerebral artery

The duplicated middle cerebral artery is an anatomical variant in which there are two middle cerebral arteries (MCA) originating from the distal end of the internal carotid artery (ICA). Supply The duplicated artery supplies the anterior temporal lobe. Differential diagnosis It should not be...
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Dural arteriovenous shunts

Dural arteriovenous shunts (DAVS) are rare congenital arteriovenous malformations (CAVMs). On the basis of clinical and anatomical features DAVS have three different types: dural sinus malformations (DSMs) infantile or juvenile DAVS (IDAVS) adult DAVS (ADAVS)
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Dural ectasia

Dural ectasia refers to ballooning or widening of the dural sac which can result in posterior vertebral scalloping and is associated with herniation of nerve root sleeves. Clinical presentation Patients with dural ectasia may present with low back pain or radicular pain in the buttocks or legs...
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Dural enhancement

Pachymeningeal enhancement, also known as dura-arachnoid enhancement 4, refers to a dural and outer layer of arachnoid pattern of enhancement seen following contrast administration and may occur in the conditions listed below: infection intracranial tumour metastases intracranial hypotension...
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Dural masses

Dural masses can be the result of a number of different tumours and conditions, although meningiomas are by far the most common. The differential of a dural mass includes: meningioma haemangiopericytoma primary dural lymphoma Rosai-Dorfman disease solitary fibrous tumour of the dura EBV-as...
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Dural metastases

Dural or pachymeningeal metastases are a relatively common cause of dural masses, although they are less common than brain metastases and meningiomas. They can occur both within the spine and intracranially - this article is focussed on intracranial dural masses.  Clinical presentation Patient...
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Dural osteoma

Dural osteomas are a cause of focal intracranial calcification (colloquially known as brain stones). They are difficult to differentiate from an ossified "burnt out" meningiomas and ossification of the falx. Some reports are actually contradictory 1,4, suggesting that at least some lesions have ...
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Dural sinus malformations

Dural sinus malformations (DSMs) are congenital vascular malformations characterized by massive dilatation of one or more dural venous sinuses. This condition is typically associated with arteriovenous shunts (DAVS). Sub types There are two types of DSMs DSM involving the confluence of sinuse...
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Dural sinus occlusive disease

Dural sinus occlusive disease (DSOD) is an infective form of dural sinus thrombosis (thrombophlebitis) commonly seen in the setting of acute otomastoiditis. It typically presents with: severe headaches high fevers sixth nerve palsy - due to involvement of Dorello's canal altered conscious st...
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Dural tail sign

The dural tail sign occurs as a result of thickening and enhancement of the dura and is most often seen adjacent to a meningioma. Initially, the sign was felt to be pathognomonic of meningiomas, however as experience grew, it has become increasingly noted to be present in many other conditions,...
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Dural venous sinuses

Dural venous sinuses are venous channels located intracranially between the two layers of dura mater (endosteal layer and meningeal layer). They can be conceptualised as trapped epidural veins. Unlike other veins in the body they run alone, not parallel to arteries. Furthermore, they are valvele...
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Dural venous sinus thrombosis

Dural venous sinus thrombosis is a subset of cerebral venous thrombosis, often coexisting with cortical or deep vein thrombosis, and presenting in similar fashions, depending mainly on which sinus is involved. As such, please refer to the cerebral venous thrombosis article for a general discuss...
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Dura mater

The dura mater, also known as the pachymeninx, is the tough outer layer of the meninges that surrounds the central nervous system and is pierced by the cranial nerves, the internal carotid arteries and the vertebral arteries.  Intracranially it is formed by two layers: outer endosteal layer, c...
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Duret haemorrhage

Duret haemorrhage is a small haemorrhage (or multiple haemorrhages) seen in the medulla or pons of patients who are rapidly herniating.  Pathology Raised supratentorial pressure causes the brainstem and mesial temporal lobes to be forced downwards through the tentorial hiatus. As a result of t...
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Dyke-Davidoff-Masson syndrome

Dyke-Davidoff-Masson syndrome (DDMS) was initially described as changes in the skull seen on skull x-ray in patients with cerebral hemiatrophy but is now applied more broadly to cross-sectional imaging also. It is characterised by: thickening of the skull vault (compensatory) enlargement of th...
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Dynamic contrast enhanced (DCE) MR perfusion

Dynamic contrast-enhanced (DCE) MR perfusion, sometimes also referred to as permeability MRI, is one of the main MRI perfusion techniques which calculates perfusion parameters by evaluating T1 shortening induced by a gadolinium-based contrast bolus passing through tissue. The most commonly calcu...
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Dynamic susceptibility contrast (DSC) MR perfusion

Dynamic susceptibility contrast (DSC) MR perfusion is one of the most frequently used techniques for MRI perfusion, and relies on the susceptibility induced signal loss on T2* weighted sequences which results from a bolus of gadolinium-based contrast passing through a capillary bed.  The most co...
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Dysembryoplastic neuroepithelial tumour

Dysembryoplastic neuroepithelial tumours (DNET) are benign (WHO Grade I) slow growing glioneuronal tumours arising from either cortical or deep grey matter. The vast majority are centred in cortical grey matter, arise from secondary germinal layers, and are frequently associated with cortical dy...
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Dysgenesis of the corpus callosum

Dysgenesis of the corpus callosum may be complete (agenesis) or partial and represents an in utero developmental anomaly. It can be divided into: primary agenesis: the corpus callosum never forms secondary dysgenesis: the corpus callosum forms normally and is subsequently destroyed Epidemiolo...
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Dysgerminoma

A dysgerminoma refers to class of tumour with germ cell origin This can refer to CNS dysgerminoma ovarian dysgerminoma See also germ cell tumours
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Dysmyelinating disorders

Dysmyelinating disorders are a subset of white matter disorders characterised by abnormal myelination 1. They are also known by the term leukodystrophy and are composed of a group of inherited conditions that are characterised by a defective structure and function of the myelin sheath 2. They a...
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Early DWI reversal in ischaemic stroke

Early DWI reversal in ischaemic stroke (also referred to as diffusion lesion reversal) is encountered early in the course of ischaemic infarction, most frequently in the setting of reperfusion within 3 to 6 hours of onset 1. In the vast majority of cases it is transient and does not represent tr...
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Eastern equine encephalitis

Eastern equine encephalitis (EEE) is one of many viral encephalitides and results from infection with the eastern equine encephalitis virus. Clinical presentation Most patients have non-specific viral prodromal symptoms for approximately one week, including fevers, headache, nausea and vomitin...
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EBV-positive diffuse large B-cell lymphoma, NOS

EBV-positive diffuse large B-cell lymphoma, NOS (not otherwise specified) is one of the immunodeficiency-associated CNS lymphomas, usually seen in elderly individuals. Unlike other EBV-associated CNS lymphomas, these individuals do not have a defined cause for immunosuppression. It is believed t...
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Eccentric target sign (cerebral toxoplasmosis)

The eccentric target sign is considered pathognomonic for cerebral toxoplasmosis. It is seen on postcontrast MRI/CT as a ring enhancing lesion with an eccentrically located enhancing mural nodule. It is believed that this mural nodule is an extension from the abscess wall itself with inflamed ve...
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Ecchordosis physaliphora

Ecchordosis physaliphora is a congenital benign hamartomatous lesion derived from notochord remnants, usually located in the retroclival prepontine region, but can be found anywhere from the skull base to the sacrum.  Terminology There has been some controversy as to whether intradural chordom...
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Ectopia lentis

Ectopia lentis refers to subluxation or dislocation of the lens of the eye secondary to dysfunction or disruption of zonular fibres.  Pathology Aetiology trauma systemic and syndromic disorders Marfan syndrome typically upwards and out most common spontaneous cause 2 homocystinuria -  ty...
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Ectopic posterior pituitary

An ectopic posterior pituitary reflects a disruption of normal embryogenesis of the posterior pituitary and is one of the more common causes of pituitary dwarfism. Although it can be an isolated abnormality, numerous other congenital central nervous system malformations have been identified. Ep...
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Efface

Efface is a term frequently used by radiologists, most often in the context of CSF containing spaces in the brain (sulci and ventricles). Unfortunately it is often used incorrectly.  The word efface, in general english usage, means to cause something to fade or disappear 1-2. In the context of...
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Elevated prolactin (differential)

Elevated prolactin can be due to a number of causes, including elevated production/secretion as well as reduced inhibition.  Prolactin is controlled by numerous homeostatic mechanisms, with tonic secretion of prolactin inhibitory hormone (dopamine) by the hypothalamus having a dominant effect 1...
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Eloquent cortex

Eloquent cortex is a term that refers to specific brain areas that directly controls function, thus damage to this areas generally produces major focal neurological deficits. Examples of eloquent cortex are:  primary motor cortex (precentral gyrus) primary somatosensory cortex (postcentral gyr...
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Embryonal tumours with multilayered rosettes (ETMR)

Embryonal tumours with multilayered rosettes (ETMR) are rare small round blue cell tumour of the central nervous system and are one of the most aggressive brain tumours usually encountered in children.  Terminology Previously embryonal tumours with multilayered rosettes (ETMR) where known as e...
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Emergency CT head (mnemonic)

A useful mnemonic which is used to read an emergency head CT scan is: Blood Can Be Very Bad Mnemonic Using a systematic approach will help to ensure that significant neuropathology will not be missed. B: blood look for epidural hematoma, subdural hematoma, intraparenchymal hemorrhage, intra...
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Empty delta sign

The empty delta sign is a CT sign of dural venous sinus thrombosis of the superior sagittal sinus, where contrast outlines a triangular filling defect (thrombus). It is only described with CECT-scan or MRI, not with NECT nor non-contrast MRI. Pathology The exact mechanism for this appearance i...
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Empty light bulb sign in brain death

In brain death, on HMPAO-Tc99m imaging there is absent or reduced flow in the internal carotid arteries and increased flow within the external carotid arteries. This leads to absent uptake in the brain with subsequent increased perfusion in the nasal region. This appearance has been called the e...
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Empty sella

An empty sella, also known as an empty pituitary fossa, is a relatively common incidental finding and posed more of a diagnostic problem before modern cross-sectional imaging. In addition to being incidental, a well-established association with benign intracranial hypertension is also recognised...
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Empty thecal sac sign

The empty thecal sac sign or empty sac sign is when the thecal sac appears empty on MRI of the lumbar spine, best seen on T2-weighted images. If the empty thecal sac sign is present, a diagnosis of adhesive arachnoiditis can be made.​ Radiographic features MRI There is usually no gadolinium c...
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Empyema

Empyemas are purulent inflammatory collections within a body cavity. They are similar to abscesses, which arise within parenchymal tissue rather than occupying a pre-existing anatomical space. Terminology Colloquially, the term empyema is used to refer to thoracic empyemas but there are variou...
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Encephalitis due to herpesvirus family

Although sporadic viral encephalitis is most commonly due to herpes simplex virus 1 (HSV-1) the extended herpesvirus family consists of many other viruses many of which can also infect the central nervous system. Encephalitis due to herpesvirus family include 1:   herpes simplex virus 1 (HSV-1)...
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Encephalitis lethargica

Encephalitis lethargica (EL) is a rare disease that is also known as von Economo encephalitis. It affects the midbrain and basal ganglia, and the exact aetiology is unknown.  Clinical presentation Symptoms are initially that of pharyngitis followed by lethargy, extrapyramidal movements (parkin...
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Encephalocoele

Encephalocoele, also known as meningoencephalocele, is a form of neural tube defect and a type of cephalocoele where brain tissue and overlying meninges herniate out through a defect in the cranium.  Terminology It should be distinguished from cranial meningocele in which the lesion contains o...
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Encephalocraniocutaneous lipomatosis

Encephalocraniocutaneous lipomatosis (ECCL), also known as Haberland syndrome, is a rare congenital neurocutaneous syndrome characterised by unilateral lipomas of the cranium, face, and neck, ipsilateral lipodermoids of the eye, and ipsilateral brain anomalies. The clinical features of ECCL ove...
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Encephalomalacia

Encephalomalacia is term given to describe softening or loss of brain parenchyma with or without surrounding gliosis, as a late manifestation of injury.  Clinical presentation asymptomatic  serve as a focus of seizure Pathology Encephalomalacia is the end result of liquefactive necrosis of ...
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Endolymphatic sac tumour

Endolymphatic sac tumours (ELST) are very rare, locally invasive tumours of endolymphatic sac. Early detection of these tumours is critical, because early surgical intervention may prevent further hearing loss. Endolymphatic sac tumours do not metastasize but are highly locally aggressive.  Epi...
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Enlarged sella turcica (differential)

Enlargement of sella turcica can be seen in situations including the following: empty sella syndrome slight globular enlargement of the sella with no erosion, destruction or posterior displacement of dorsum sellae intracranial hypertension enlargement with erosion of anterior cortex of dorsu...
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En plaque meningioma

En plaque meningiomas refer to a specific meningioma macroscopic appearance characterised by diffuse and extensive dural involvement, usually with extracranial extension into calvarium, orbit, and soft tissues. These tumours are thought to have a collar-like or sheet-like growth along the dura m...
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Enterovirus 71

Enterovirus 71 is one of the viruses that causes hand-foot-and-mouth disease in children. It is an enterovirus, one of the picornaviruses. Infection with enterovirus 71 predominantly results in a vesicular rash of the hands and feet that follows a prodrome of symptoms including fever, vomiting ...
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Enterovirus rhomboencephalitis

Enterovirus rhomboencephalitis is the most common neurological complication of enterovirus infection 1. Clinical presentation Enterovirus rhomboencephalitis causes acute and severe neurologic disorders such as ataxia, nystagmus, oculomotor palsies, or bulbar palsy. In some cases, neurologic af...
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Entorhinal cortex

The entorhinal cortex (Brodmann area 28) is located in the mesial temporal lobe and acts as the interface between the hippocampus and the neocortex. It has been considered part of the hippocampal formation (along with Ammon’s horn, subiculum and presubiculum), but is difficult to precisely local...
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Eosinophilia myalgia syndrome

Eosinophilia myalgia syndrome (EMS) is a fatal neurological condition caused by ingestion of improperly manufactured L-tryptophan.  Impurities and/or metabolites that block histamine degradation result in peripheral blood eosinophilia and myalgia.   In the brain, cortical and basal ganglia atro...
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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 cyst

Ependymal cysts are rare benign neuroepithelial cysts lined by ependymal cells. Most are small and asymptomatic and only cause symptoms if large. On imaging, these cysts are essentially indistinguishable from other intraventricular simple cysts (e.g. intraventricular arachnoid cysts). Epidemio...
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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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Ependymitis granularis

Ependymitis granularis sounds far more worrying than it actually is. The term refers to symmetrical foci of periventricular high T2 and FLAIR signal hyperintensity anterior and lateral to the frontal horns. It is just an anatomical variant, usually small, less than 1 cm, and have a triangular mo...
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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 cerebral spina...
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Ependymoma

Ependymomas represent a relatively broad group of glial tumours most often arising from the lining the ventricles of the brain or the central canal of the spinal cord. They account for ~5% of all neuroepithelial neoplasms, ~10% of all paediatric brain tumours and up to 33% of brain tumours occur...
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Ependymoma RELA fusion-positive

Ependymoma RELA fusion-positive is a recently accepted variant of ependymoma, only recognised in the 2016 update to the WHO classification of CNS tumours. They are the most common type of supratentorial ependymoma in children, and not found in the posterior fossa or spinal cord.  Epidemiology ...
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Ependymoma vs astrocytoma of the spinal cord

A number of factors are useful when differentiating between spinal cord ependymoma and spinal cord astrocytoma.  Ependymoma child or adult more central in location bone remodelling is common low T1 signal well-defined enhancement syrinx is more common haemorrhage is more common Astrocyt...
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Epidermoid cyst

The term epidermoid cyst can refer to a: epidermal inclusion cyst intracranial epidermoid cyst splenic epidermoid cyst spinal epidermoid cyst testicular epidermoid cyst
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Epidural angiolipoma

Epidural angiolipomas are rare benign tumours composed of mature adipocytes and abnormal vessels.  Epidemiology Epidural angiolipomas are more frequently encountered in women, and typically in middle age (40-50 years of age) 1.  Clinical presentation In keeping with the slow growth of these ...
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Epidural blood patch

Epidural blood patch is a treatment option for patients with craniospinal hypotension or post lumbar puncture headaches. The procedure can be done blind or under fluoroscopic or CT guidance, and is performed predominantly by radiologists and anaesthetists.  Indications craniospinal hypotension...
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Epidural empyema

Epidemiology and demography Epidural empyemas are relatively rare, but acount for ca. 30% of all intracranial infections. They can appear at every age with no sex preference. Etiology The most common pathogens are streptococci, Haemophilus influenzae, Staphylococcus aureus and Staphylococcus ...
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Epidural lipomatosis

Epidural lipomatosis refers to an excessive accumulation of fat within the spinal epidural space, typically in the lumbar region, such that the thecal sac is compressed, and in some instances results in compressive symptoms.  Epidemiology Demographic of affected individuals reflects the underl...
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Epilepsy

Epilepsy is a common neurological disorder that has a varied presentation and requires two or more unprovoked seizures at least 24 hours apart for diagnosis. MRI is the modality of choice for epilepsy, most often investigating for an underlying cause, especially in adults.  Epidemiology Epilep...
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Epilepsy protocol (MRI)

MRI protocol for epilepsy is a group of MRI sequences put together to improve sensitivity and specificity in identifying possible structural abnormalities that underlie seizure disorders (e.g. mesial temporal sclerosis and malformation of cortical development). MRI is the imaging procedure of ch...
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Epithalamus

The epithalamus is a dorsal posterior segment of the diencephalon which includes the habenula, the stria medullaris and the pineal gland. Its function is the connection between the limbic system to other parts of the brain.
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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). 
Article

Epithelioid glioblastoma

Epithelioid glioblastoma is a variant of glioblastoma (along with gliosarcoma and giant cell glioblastoma) only recently added to the WHO classification of CNS tumours as part of the 2016 update 1.  Terminology Whether or not epithelioid glioblastomas are distinct from rhabdoid glioblastomas i...
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Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell, non-familial multisystemic granulomatosis, 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 midd...
Article

État criblé

État criblé, also known as status cribrosum, is a term that describes the diffusely widened perivascular spaces (Virchow-Robin spaces) in the basal ganglia, especially in the corpus striatum. It is usually symmetrical, with the perivascular spaces showing CSF signal and without diffusion restric...
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État lacunaire

État lacunaire is a term describing the presence of multiple lacunar infarcts, which are ischemic strokes due to occlusion of penetrating cerebral arterioles, especially in the basal ganglia. The term has been strongly described as a pathological substrate for a multi-infarct vascular dementia 4...
Article

Ethylene glycol toxicity

Ethylene glycol, best known as a component of antifreeze, has been ingested both deliberately and accidentally, resulting in neurotoxicity and renal failure.  Clinical presentation A delay is present between ingestion and development of symptoms. Initial symptoms of ethylene glycol toxicity is...
Article

Evans' index

The Evans' index is the ratio of maximum width of the frontal horns of the lateral ventricles and maximal internal diameter of skull at the same level employed in axial CT and MRI images. This ratio varies with the age and sex. It is useful as a marker of ventricular volume and thus has been pr...
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Exencephaly

Exencephaly is a lethal congenital fetal brain developmental anomaly (neural tube defect) considered to be a precursor to anencephaly in the acrania-exencephaly-anencephaly sequence. Pathology It is characterised by calvarial absence and loss of fetal brain tissue to variable degrees and is co...
Article

External auditory canal atresia

External auditory canal atresia (EACA) is characterised by complete or incomplete bony atresia of the external auditory canal (EAC) and, especially when seen in the setting of an associated syndrome, a dysplastic auricle and an abnormal middle ear cavity. Epidemiology The incidence is 1 in 10,...
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External capsule

The external capsule is a series of white matter tracts in the brain. They are situated between the putamen and claustrum.
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External petrosal nerve

The external petrosal nerve is one of the three branches from the geniculate ganglion. It carries sympathetic fibers to the middle meningeal artery.
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External ventricular drain

External ventricular drains (EVDs) are a common neurosurgical procedure used to monitor and treat raised intracranial pressure in the acute setting.  Treatment and prognosis Complications infection EVD malfunction EVD malposition intracranial haemorrhage (e.g. subdural, intraventricular) ...
Article

Extra-axial

Extra-axial is a descriptive term to denote lesions that are external to the brain parenchyma, in contrast to intra-axial which describes lesions within the brain substance.  Radiographic features Often it is trivially easy to distinguish an intra-axial from an extra-axial mass. In many cases,...
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Extra-axial collection (summary)

Extra-axial collections are collections of fluid within the skull, but outside the brain parenchyma. They may be comprised of CSF, blood or pus and may exist in the extradural, subdural or subarachnoid space.  Reference article This is a summary article; we do not have a more in-depth referenc...
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Extra-axial masses (differential)

Extra-axial masses of the intracranial compartment have a wide range of differentials, ranging from benign developmental cysts to malignant tumours.  Differential diagnosis neoplasms chordoma choroid plexus papilloma/carcinoma cranial nerve schwannoma meninges meningioma solitary fibrous...
Article

Extraconal orbital lesions

Extraconal orbital lesions include lesions which arise from structures within the extraconal orbital space and those extending from adjacent structures into the orbits. Differential diagnosis Intraorbital lesions dermoid cyst: most common lesion in paediatrics  lacrimial gland lesions dacry...
Article

Extracranial brain herniation

Extracranial brain herniation refers to herniation of brain tissue external to the calvaria through a skull bone defect, which may be post-traumatic or post-surgical. Unlike encephaloceles, brain herniation is surrounded by the meninges.  The herniated brain tissue requires surgical reduction a...

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