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.

2,567 results found
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Trigeminal nerve branches (mnemonic)

A mnemonic for remembering the names of the skull foramina that the division of the trigeminal nerve (CN V) pass through is: Standing Room Only Mnemonic S: superior orbital fissure (ophthalmic division of trigeminal nerve) R: foramen rotundum (maxillary division of trigeminal nerve) O: fora...
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Trigeminal nerve stimulator

Trigeminal nerve stimulators are devices intended for the treatment of trigeminal neuropathic pain (e.g. trigeminal neuralgia, post-herpetic, post-surgical, multiple sclerosis-associated trigeminal neuropathies), although evidence is lacking and implantation of devices, for this reason, is consi...
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Trigeminal neuralgia

Trigeminal neuralgia or tic douloureux corresponds to a clinical manifestation of sudden severe paroxysms of excruciating pain on one side of the face which usually lasts a few seconds to a few minutes, involving one or more branches of the trigeminal nerve (CN V). Vascular compression is the mo...
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Trigeminal neuralgia protocol (MRI)

MRI protocol for trigeminal neuralgia assessment is a group of MRI sequences put together to best approach a possible cause for this condition. The diagnosis of trigeminal neuralgia is based on patient's history, and an imaging study is usually indicated when alert signs are noted. Imaging can ...
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Trigeminal schwannoma

Trigeminal schwannomas are uncommon slow-growing encapsulated tumors composed of schwann cells. They are the second most common intracranial schwannoma, far less common than vestibular schwannoma, and has a predominantly benign growth.  Epidemiology  Patients usually present in middle age, typ...
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Trigone of the lateral ventricle

The trigone of the lateral ventricle is an area of the lateral ventricle at the confluence of the occipital and temporal horns. It refers either to the three-dimensional space at the transition between the body of the lateral ventricle and the occipital and temporal horns, in which case it is al...
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Trigonocephaly

Trigonocephaly refers to the triangular appearance of the frontal skull created by premature fusion of the metopic suture (metopic craniosynostosis) 2.  Trigonocephaly accounts for around 5% of all craniosynostosis cases. Pathology The metopic suture divides the frontal bones in the midline. I...
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Trilateral retinoblastoma

Trilateral retinoblastoma refers to the combination of retinoblastoma (usually bilateral) and pineoblastoma. This relationship highlights the close relationship between these highly aggressive small round blue cell tumors. It affects only a minority of patients with retinoblastoma (1.5-5%) and ...
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Trochlear nerve

The trochlear nerve is the fourth cranial nerve and is the motor nerve of the superior oblique muscle of the eye.  It can be divided into four parts: nucleus and an intraparenchymal portion cisternal portion cavernous sinus portion orbital portion Gross anatomy Nucleus and intraparenchy...
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Trochlear nerve palsy

Trochlear nerve palsies, or fourth nerve palsies, result in weakness of the superior oblique muscle. Clinical presentation Vertical diplopia and ipsilateral hypertropia in the absence of ptosis, combined with a head tilt away from the affected side, are strongly suggestive of trochlear nerve p...
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Trotter syndrome

Trotter syndrome relates to advanced nasopharyngeal carcinoma and is the constellation of: unilateral conductive hearing loss due to middle ear effusion trigeminal neuralgia due to perineural spread soft palate immobility
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Trumpeted internal acoustic meatus sign

A trumpeted internal acoustic meatus (IAM) is an indirect sign of a vestibular schwannoma and is useful in helping to differentiate between one and other cerebellopontine angle entities, especially from a meningioma which typically does not extend into the meatus and is more often associated wit...
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Tuber cinereum

Tuber cinereum is a hollow eminence of gray matter. It is a part of the hypothalamus. Gross anatomy It is located between mammillary bodies and optic chiasm. Devoid of the blood brain barrier, it normally enhances after contrast administration. Relations It is continuous: laterally: with an...
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Tuberculoma

Tuberculomas or tuberculous granulomas are well defined focal masses that result from Mycobacterium tuberculosis infection and are one of the more severe morphological forms of tuberculosis. Tuberculomas most commonly occur in the brain (see: CNS tuberculosis) and the lung (see: pulmonary tuberc...
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Tuberculosis

Tuberculosis encompasses an enormously wide disease spectrum affecting multiple organs and body systems predominantly caused by the organism Mycobacterium tuberculosis. A small proportion can also be caused Mycobacterium bovis.  Epidemiology Although tuberculosis continues to be very common in...
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Tuberculosis (intracranial manifestations)

Tuberculosis of the central nervous system can result from either haematogenous spread from distant systemic infection (e.g. pulmonary tuberculosis) or direct extension from local infection (e.g. tuberculous otomastoiditis). Intracranial manifestations of tuberculosis are protean and can affect...
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Tuberculous encephalopathy

Tuberculous (TB) encephalopathy is a rare manifestation of CNS tuberculosis and is exclusively seen in children and infants with pulmonary TB. It is characterized by cerebral edema sometimes with features similar to acute disseminated encephalomyelitis (ADEM), and may manifest with a variety of ...
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Tuberculous meningitis

Tuberculous meningitis is the most common presentation of intracranial tuberculosis, and usually refers to infection of the leptomeninges. Uncommonly tuberculosis can be limited to the pachymeninges (dura mater), it is called tuberculous pachymeningitis and is discussed separately.  The remaind...
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Tuberculous otomastoiditis

Tuberculous otomastoiditis is an uncommon form of acute otomastoiditis that occurs secondary to tuberculosis infection, although its frequency is increasing as a result of greater population of immunocompromised patients. Clinical presentation Classically it is described as presenting with pa...
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Tuberculous pachymeningitis

Tuberculous pachymeningitis is a rare form of CNS tuberculosis characterized by a chronic tuberculous infection leading to a dura mater involvement. Common sites of involvement are cavernous sinuses, floor of middle cranial fossa and tentorium. This condition should not be confused with the com...
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Tuberculous rhombencephalitis

Tuberculous rhombencephalitis is a particular form of neurotuberculosis that affects primarily the hindbrain (brainstem and cerebellum) and usually is manifested as a tuberculoma. Please refer to the article on rhombencephalitis for a general discussion of that entity. Epidemiology Studies ha...
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Tuberculous spondylitis versus pyogenic spondylitis

Tuberculous spondylitis and pyogenic spondylitis are both common causes of spinal infection. Imaging findings of these 2 diseases can be challenging to distinguish, yet crucial because the treatments for these infections are particularly different 2. Radiographic features Useful distinguishing...
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Tuberculum sellae - occipital protuberance line

The tuberculum sellae-occipital protuberance line (TS-OP line), is an imaging reference line that runs almost parallel to the anterior commissure-posterior commissure line (AC-PC line) 1.It is a practical reference line for reformatting or tilting of the gantry during CT acquisition of the head ...
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Tuberous sclerosis

Tuberous sclerosis, also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterized by the development of multiple benign tumors of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosis has an in...
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Tuberous sclerosis (diagnostic criteria)

The tuberous sclerosis diagnostic criteria have been developed to aid the diagnosis of tuberous sclerosis and have most recently been updated in 2012 by the International Tuberous Sclerosis Complex Consensus Group (at time of writing - 2019) 1.  Criteria Genetic criteria The identification of...
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Tubulinopathy

Tubulinopathy refers to a wide spectrum of cortical malformations that result from defects in genes encoding the tubulin protein that regulates neuronal migration during brain development. Clinical presentation Some series report a high prevalence of seizures during infancy which may the initi...
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Tumefactive demyelinating lesion

Tumefactive demyelinating lesion (TDL), also sometimes referred to as monofocal acute inflammatory demyelination (MAID), is a locally aggressive form of demyelination, usually manifesting as a solitary lesion (or sometimes a couple of lesions) greater than 2 cm that may mimic a neoplasm on imagi...
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Tumefactive multiple sclerosis

Tumefactive multiple sclerosis is a term used to describe patients with established multiple sclerosis who develop large aggressive demyelinating lesions, similar/identical in appearance to those seen in sporadic tumefactive demyelinating lesions (TDL). TDL is now considered to be a separate ent...
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Tumefactive perivascular spaces

Tumefactive perivascular spaces (TPVS) is a rare finding of enlargement of perivascular spaces. It is important to recognize this condition as it can be easily mistaken for a neoplasm and also rarely local mass effect from TPVS can result in a complication. Clinical presentation Small case ser...
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Tumor pseudoprogression

Tumor pseudoprogression, also known just as pseudoprogression, corresponds to an increase of lesion size related to treatment, which simulates progressive disease. The term is largely used in brain tumors imaging follow-up, especially for high grade gliomas (e.g. glioblastoma), and is observed a...
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Tumor pseudoresponse

Tumor pseudoresponse, also known just as pseudoresponse, refers to the phenomenon of tumors appearing to respond to a specific treatment on imaging criteria, when the lesion actually remains stable or has even progressed. The term is largely used in brain tumors imaging follow-up, especially fo...
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Tumors of the meninges (differential)

Tumors of the meninges are a heterogeneous group of lesions which usually occur as extra-axial masses.  Although a large number of lesions that can involve meninges are scattered throughout the  WHO classification of CNS tumors, the main entities to be considered include:  meningioma and numero...
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Tumor-to-tumor metastasis

A tumor-to-tumor metastasis, also known as a collision tumor, is a rare metastatic process in which a primary malignant tumor ('donor') metastasizes to another tumor ('recipient'), most commonly a benign tumor such as a meningioma. Epidemiology Tumor-to-tumor metastasis is considered very rare...
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Turcot syndrome

Turcot syndrome is one of the variations in polyposis syndromes. It is characterized by multiple colonic polyps and an increased risk of colon and primary brain cancers. Epidemiology Turcot syndrome is a rare disease. Patients typically present in the second decade 3. Pathology Turcot syndro...
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Twig-like middle cerebral artery

A Twig-like middle cerebral artery or rete mirabile anomaly is a term to describe a discontinuity of a single trunk of the middle cerebral artery with several small vessels reconstituting the artery and giving it a twig-like appearance. Distally, normal vascular anatomy of the MCA branches need ...
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Tympanic membrane retraction

Tympanic membrane retraction usually occurs when a portion of the tympanic membrane becomes weakened and is pulled inwards by the negative pressure within the middle ear.  Pathology As the tympanic membrane is pulled inwards (medially), it can become draped over the ossicles, resulting in a va...
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Typhoid fever

Typhoid fever or just typhoid is an infectious disease caused by the Salmonella enterica serovar Typhi bacterium, usually spread by the orofecal route. The condition is characterized by severe fever, acute systemic symptoms, with occasionally serious enterocolic complications. Terminology Do n...
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Ulegyria

Ulegyria refers to a shrunken and flattened cortex usually due to global hypoxic ischemic injury in term infants, centering on the deepest portion of gyri, usually in the parasagittal region. It is here that perfusion is most tenuous and, therefore, most susceptible to ischemic damage. Clinical...
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Ultrahigh field MRI

Ultrahigh field (UHF) magnetic resonance imaging refers to imaging done on any MRI scanner with a main magnetic field (B0) strength of 7 tesla or greater. Until recently purely a research tool, following the introduction of the first 7 T clinical scanner in 2017, there are now a slowly increasin...
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Ultrasound carotids (summary)

This is a basic article for medical students and other non-radiologists. US (ultrasound) carotids is a standard test performed as part of the assessment of the cranial arterial blood supply. Reference article This is a summary article; we do not have a more in-depth reference article. Summar...
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Uncal herniation

Uncal herniation is a subtype of transtentorial downward brain herniation that involves the uncus, usually related to cerebral mass effect increasing the intracranial pressure. Clinical presentation pupils and globe clinical features 3 initially, an ipsilateral dilated pupil that is unrespons...
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Uncinate fasciculus

The uncinate fasciculus is a white matter tract that connects the uncus (Brodmann area 35), the anterior temporal areas (temporal pole; Brodmann area 38), the amygdala and the hippocampal gyrus (Brodmann areas 36 and 30) with areas of the frontal lobe (polar and orbital cortex); runs - forming a...
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Unclassified cerebellar dysplasia

Unclassified cerebellar dysplasia is defined as focal or diffuse dysplasia of cerebellar hemispheres or vermis not associated with other known malformations or syndromes. Clinical presentation Can present with hypotonia, microcephaly or speech delay. Radiographic features MRI asymmetry or f...
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Uncus

The uncus (plural: unci) is the innermost part of the anterior parahippocampal gyrus, part of the mesial temporal lobe.  Gross anatomy The uncus is the most anterior portion of the medial parahippocampal gyrus. It belongs to the limbic system. Housing the primary olfactory cortex, it is part o...
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Unverricht-Lundborg disease

Unverricht-Lundborg disease (ULD or EPM1) inherited neurodegenerative disorder which often results in a progressive myoclonic epilepsy. Epidemiology It is considered the most common single cause of progressive myoclonic epilepsy worldwide. Pathology Genetics It carries an autosomal recessiv...
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Upper T sign

The upper T sign is one of the features useful in identifying the central sulcus of the cerebral cortex on cross-sectional imaging. It relies on identifying the superior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulc...
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Uremic encephalopathy

Uremic encephalopathy (UE) is an acquired toxic syndrome characterized by delirium in patients with untreated or inadequately treated end-stage renal disease. Uremic encephalopathy is often associated with lethargy and confusion in the acute phase, which can progress to seizures, coma, or both i...
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Urbach-Wiethe disease

Urbach-Wiethe disease, also known as lipoid proteinosis or hyalinosis cutis et mucosae, is a rare autosomal recessive genodermatosis that primarily affects the skin, upper respiratory tract, and central nervous system (CNS). Epidemiology Urbach-Wiethe disease is a very rare condition, with few...
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U sign (central sulcus)

The U sign denotes the characteristic U-shaped appearance of the subcentral gyrus which surrounds the inferolateral end of the central sulcus and abuts the lateral (Sylvian) fissure. It has been found, at least in one study, to be the most reliable anatomical feature to identify the central sulc...
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Vagoglossopharyngeal neuralgia

Vagoglossopharyngeal neuralgia is an uncommon presentation of glossopharyngeal neuralgia where the typical symptoms of pain are associated with cardiac symptoms including arrhythmias, asystole, and syncope. It is believed to be due to complex interconnections between the nervus intermedius, the...
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Vagus nerve

The vagus nerve is the tenth (X) cranial nerve and provides the bulk of the parasympathetic input to the gastrointestinal system and to the heart. It is a complex mixed sensory, motor and parasympathetic nerve.  Gross anatomy Central connections The vagus nerve arises as multiple rootlets at ...
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Valproate-induced hyperammonemic encephalopathy

Valproate-induced hyperammonemic encephalopathy (VHE), also known as valproic acid-induced hyperammonemic encephalopathy, is a rare type of non-cirrhotic hyperammonemic encephalopathy caused by use of sodium valproate, a drug commonly used as an anti-epileptic and mood stabilizer. Epidemiology ...
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Vanishing white matter disease

Vanishing white matter disease (VWM), also known as childhood ataxia with central hypomyelination (CACH), is an exceedingly rare entity only fully described in 1997, but due to its name sometimes over-represented in differentials for white matter disease. Epidemiology Most cases are encountere...
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Variably protease-sensitive prionopathy

Variably protease-sensitive prionopathy (VPSPr) is a very rare type of sporadic human prion disease that was first described in 2008. Clinical presentation Clinical presentation is varied, but most patients demonstrate a combination of: progressive neuropsychiatric features: dementia and psyc...
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Varicella zoster virus encephalitis

Varicella zoster virus (VZV) encephalitis can be due to either an immune reaction to primary infection or reactivation of latent infection in cranial nerve or dorsal root ganglia following childhood chickenpox. Manifestations following primary infection include:  cerebellar ataxia meningoence...
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VASARI MRI feature set

The VASARI (Visually AcceSAble Rembrandt Images) MRI feature set is a system designed to enable consistent description of gliomas using a set of defined visual features and controlled vocabulary. It is the result of work by The Cancer Imaging Archive (TCIA) who publish relevant guides to use, an...
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Vascular dementia

Vascular dementia, also known as vascular cognitive impairment, is the second most common cause of dementia after the far more common Alzheimer disease. It is primarily seen in patients with atherosclerosis and chronic hypertension and results from the accumulation of multiple white matter lesio...
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Vasculopathies caused by varicella zoster virus

Vasculopathies caused by varicella zoster virus (VZV) represent a group of illnesses involving both small and large CNS arteries caused by a inflammatory process involving the media and the vascular endothelium. Usually it occurs in immunocompromised individuals due the viral reactivation and sp...
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Vasogenic cerebral edema

Vasogenic cerebral edema refers to a type of cerebral edema in which the blood brain barrier (BBB) is disrupted (cf. cytotoxic cerebral edema, where the blood-brain barrier remains intact). It is an extracellular edema which mainly affects the white matter via leakage of fluid from capillaries. ...
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Vein of Galen

The vein of Galen, also known as the great cerebral vein or great vein of Galen, is a short trunk formed by the union of the two internal cerebral veins and basal veins of Rosenthal. It lies in the quadrigeminal cistern. It curves backward and upward around the posterior border of the splenium o...
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Vein of Galen aneurysmal malformation

Vein of Galen aneurysmal malformations (VGAMs), probably better termed as median prosencephalic arteriovenous fistulas, are uncommon intracranial anomalies that tend to present dramatically during early childhood with features of a left-to-right shunt and high-output cardiac failure. Epidemiolo...
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Vein of Labbé

The vein of Labbé, also known as inferior anastomotic vein, is part of the superficial venous system of the brain.  The vein of Labbé is the largest channel that crosses the temporal lobe between the Sylvian fissure and the transverse sinus and connects the superficial middle cerebral vein to t...
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Velum interpositum

The velum interpositum is a small membrane containing a potential space just above and anterior to the pineal gland which can become enlarged to form a cavum velum interpositum.  Gross anatomy The velum interpositum is formed by an invagination of pia mater forming a triangular membrane the ap...
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Venous circle of Trolard

The anastomotic venous circle of the base of the brain 1, also referred to as the venous circle of Trolard 2,3,5, is an inconsistently found venous homologue of the better-known arterial circle of Willis. It should not be confused with other venous structures also described by Trolard such as t...
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Venous distension sign

The venous distension sign is a finding that may be identified on sagittal imaging of the dural venous sinuses which is said to have a diagnostic sensitivity and specificity of 94% for intracranial hypotension. The sign is positive when there is a convex inferior margin of the midportion of the...
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Venous vascular malformation of the facial nerve

Venous vascular malformations of the facial nerve, previously known as facial nerve hemangiomas, are rare benign vascular malformations of the facial nerve usually presenting as a facial nerve palsy, which can be rapid in onset mimicking a Bell palsy.  Terminology As they do not appear to have...
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Ventral cord herniation

Ventral cord herniation, also known by a variety of other terms such as spontaneous thoracic cord herniation or idiopathic spinal cord herniation, is a rare cause of focal myelopathy due to herniation of the thoracic cord through a dural defect.  Post-surgical cord herniation can occur at any l...
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Ventral cord syndrome

Ventral cord syndrome (also known as anterior cord syndrome) is one of the incomplete cord syndromes and affects the anterior parts of the cord resulting in a pattern of neurological dysfunction dominated by motor paralysis and loss of pain, temperature and autonomic function. Anterior spinal ar...
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Ventral horn

The ventral horn of the spinal cord is one of the grey longitudinal columns found within the spinal cord. It contains the cell bodies of the lower motor neurons which have axons leaving via the ventral spinal roots on their way to innervate muscle fibers. Gross anatomy On transverse section of...
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Ventricular system

The ventricular system in the brain is composed of CSF-filled ventricles and their connecting foraminae. CSF is produced by ependymal cells which line the ventricles. They are continuous with the central canal. Ventricles contain around 1/5 of normal adult CSF volume, which is around 20-25 ml. ...
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Ventriculitis

Ventriculitis (plural: ventriculitides) refers to inflammation, usually due to infection, of the ependymal lining of the cerebral ventricles. It is most often due to meningitis. Terminology The entity or closely related variants have also been variously referred to as ependymitis, ventricular ...
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Ventriculoatrial shunt

Ventriculoatrial shunting is an alternative option for the diversion of CSF and relief of hydrocephalus. In this technique, the distal catheter is placed in the right atrium or even in the superior vena cava 1,2.  It is not the only alternative for the traditional ventriculoperitoneal shunt, an...
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Ventriculogallbladder shunt

Ventriculogallbladder shunts are a rare form of cerebrospinal fluid diversion, used when a ventriculoperitoneal shunt is not possible (e.g. intra-abdominal adhesions, peritonitis). Differential diagnosis a ventriculoperitoneal shunt in a right upper quadrant CSFoma See also ventriculoperiton...
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Ventriculomegaly

Ventriculomegaly is defined as enlargement of the ventricles. Simply, there are two causes: hydrocephalus communicating non-communicating parenchymal atrophy Refer to the article on hydrocephalus vs atrophy for more details on how to differentiate both entities. 
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Ventriculoperitoneal shunt

Ventriculoperitoneal (VP) shunts are a device used to shunt cerebrospinal fluid in the treatment of hydrocephalus. As the name suggests, a catheter is placed with its tip in the ventricle. The external portion of the catheter is connected to a valve that regulates the flow of CSF based on a pre...
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Ventriculopleural shunt

Ventriculopleural shunting is an alternative option for the diversion of CSF and relief of hydrocephalus. In this technique, the distal catheter is placed in the pleural space. It is an alternative to a ventriculoperitoneal shunt (often considered a next most used alternative). Complications s...
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Ventriculus terminalis

The ventriculus terminalis or terminal ventricle of Krause, also known as the 5th ventricle, is an ependymal-lined fusiform dilatation of the terminal central canal of the spinal cord, positioned at the transition from the tip of the conus medullaris to the origin of the filum terminale. This di...
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Venus necklace

A Venus necklace is a term almost never used, but for the sake of completeness is included here. It has been used by some authors 1 to describe a series of T2 hyperintense lesions on the inferior surface of the corpus callosum in the midline (callososeptal interface), most frequently seen in mul...
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Vermian lobulation

Evaluation of vermian lobulation is essential in assessment of the vermian maturity. MRI is a useful tool in assessment of the fetal posterior fossa. Radiographic features Normal vermian lobulation by weeks 1: by 21 weeks: the prepyramidal fissure can be seen between the tuber and pyramis 21...
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Vermian maturity assessment (approach)

Radiological evaluation of the posterior fossa is an essential part of the routine fetal assessment, including vermian maturity assessment. Radiographic features Ultrasonography is a readily available diagnostic tool in the assessment of the fetal posterior fossa but is sometimes limited due t...
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Vermis

Gross anatomy The vermis (pl: vermes) of the cerebellum is an unpaired medial structure which separates the cerebellar hemispheres. The neocerebellar posterior lobes join in the midline behind the primary fissure to separate the vermis into superior and inferior portions. The vermis can be furt...
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Vernet syndrome

Vernet syndrome, also known as jugular foramen syndrome, is a constellation of cranial nerve palsies due to compression from a jugular foramen lesion, such as a glomus jugulare tumor, schwannoma, or metastasis 2. Clinical presentation It consists of motor paralysis of: glossopharyngeal nerve ...
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Verocay bodies

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

Vertebral artery dissection, like arterial dissection elsewhere, is a result of blood entering the media through a tear in the intima. It is potentially lethal and can be difficult to diagnose clinically and radiologically. Epidemiology Vertebral artery dissections have an incidence of 1-5 per...
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Vertebral artery thrombosis

Vertebral artery thrombosis results in complete or partial occlusion of the vertebral artery and alteration of blood flow to the posterior cerebral circulation. Ischemia or infarction to structures supplied by these arteries may result in a range of symptoms. brainstem cerebellum occipital lo...
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Vertebral scalloping

Vertebral scalloping is a concavity to the posterior (or less commonly anterior) aspect of the vertebral body when viewed in a lateral projection. A small amount of concavity is normal, as is concavity of the anterior vertebral body (see vertebral body squaring). Posterior scalloping Causes of...
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Vestibular neuritis

The vestibular nerve is a large division of cranial nerve eight (CN VIII) that transfers the equilibrium information from the inner ear to the central nervous system. The cochlear nerve is the other large branch of the vestibulocochlear nerve that transports the sounds findings to the central ne...
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Vestibular schwannoma

Vestibular schwannomas, also known as acoustic neuromas, are relatively common tumors that arise from the vestibulocochlear nerve (CN VIII) and represent ~80% of cerebellopontine angle (CPA) masses. Bilateral vestibular schwannomas are strongly suggestive of neurofibromatosis type 2 (NF2). On i...
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Vestibulocochlear nerve

The vestibulocochlear nerve is the eighth cranial nerve and has two roles: innervation to the cochlea for hearing innervation to the vestibule for acceleration and balance senses Gross anatomy It emerges between the pons and the medulla, lateral to the facial nerve and nervus intermedius, pa...
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Vidian nerve

Vidian nerve, also known as the nerve of the pterygoid canal or nerve of the Vidian canal, is so named because of the canal in which is travels: the Vidian canal. It is formed by the confluence of two nerves: greater superfical petrosal nerve (from the geniculate ganglion of the facial nerve) ...
Article

Viking helmet appearance

The Viking helmet appearance refers to the morphology of the lateral ventricles in the coronal plane in patients with dysgenesis of the corpus callosum. The cingulate gyrus is everted into narrowed and elongated frontal horns. An alternative name is moose head appearance. Other names include st...
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Viral encephalitides

Viral encephalitides are the result of brain parenchymal infection by a number of different viruses, many of which have similar presentations and imaging features. Specific diagnosis often requires PCR.  For viral infection of the meninges, please refer to the general article on viral meningiti...
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Viral meningitis

Viral meningitides correspond to a relatively common and self-limited type of CNS infection clinically diagnosed based on the cerebrospinal fluid analysis and proportionally more frequent in young children than adults. Enteroviruses represent nowadays the most common cause of viral meningitis fo...

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