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.

2,302 results found
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Tight filum terminale syndrome

Tight filum terminale syndrome is caused by incomplete involution of the distal spinal cord during embryogenesis. This leads to development of an abnormally thickened filum terminale, which may be associated with lipomas or cysts within the filum. Tight filum terminale syndrome is always associ...
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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...
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Toast classification in acute ischemic stroke

The TOAST (trial of ORG 10172 in acute stroke treatment) classification denotes five sub types of ischemic stroke. large-artery atherosclerosis (embolus / thrombosis)* cardioembolism (high-risk / medium-risk)* small-vessel occlusion (lacune)* stroke of other determined etiology * stroke of ...
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Todd paralysis

Todd paralysis, also known as Todd paresis or postictal paralysis, describes transient focal neurological deficits after an epileptic seizure. It is an important clinical and imaging differential diagnosis of ischemic stroke presenting with a seizure.   Epidemiology The incidence of Todd paral...
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Tolosa-Hunt syndrome

Tolosa-Hunt syndrome (THS) is an idiopathic inflammatory condition that involves the cavernous sinus and orbital apex, and is essentially a clinical diagnosis of exclusion. Clinical presentation Clinically it refers to the presence of a painful ophthalmoplegia secondary to surrounding cavernou...
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Tonsillar herniation

Tonsillar herniation is a type of cerebral herniation characterized by the inferior descent of the cerebellar tonsils below the foramen magnum. The terminology of caudally displaced tonsils is discussed in the article on cerebellar tonsillar ectopia. Pathology It is a secondary sign of signif...
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Top of the basilar syndrome

Top of the basilar syndrome, also known as rostral brainstem infarction, occurs when there is thromboembolic occlusion of the top of the basilar artery. This results in bilateral thalamic ischemia due to occlusion of perforator vessels. Clinical presentation Clinically, top of the basilar synd...
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Torticollis

Torticollis (wryneck) is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group.  Pathology Torticollis can be acute (<1 week) or chronic (...
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Toxic leukoencephalopathy

Toxic leukoencephalopathy is an encephalopathy predominantly affecting white matter as a result of a toxic substance. The presentation can either be chronic or acute. In the acute phase, acute toxic leukoencephalopathy can have a characteristic and profound MR imaging appearance that is potentia...
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Toxoplasmosis

Toxoplasmosis is a common worldwide parasitic disease caused by the protozoan Toxoplasma gondii. It is usually an asymptomatic infection, but it is related with several sequelae when acquired in-utero or related with cerebral abscesses due to its reactivation in immunocompromised patients (e.g. ...
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Toxoplasmosis vs lymphoma

Toxoplasmosis and lymphoma are frequently differential diagnoses in patients with HIV/AIDS and as treatment is substantially different distinguishing the two is important.  In many instances, the imaging appearance is classic and differentiation is not problematic; however, in 50-80% of cases, ...
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Tram-track sign (brain)

Tram-track sign in the brain refers to the parallel calcification of the cortex in patients with Sturge-Weber syndrome 1.  It should not be confused with other tram-track signs elsewhere in the body. 
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Tram-track sign (orbit)

Tram-track sign refers to the parallel thickening and enhancement around the optic nerve, and is most frequently seen in the setting of optic nerve meningioma. It may however also be seen in 1: orbital pseudotumour perioptic neuritis orbital sarcoidosis oribtal leukemia orbital lymphoma or...
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Transalar herniation

Transalar (transsphenoidal) herniation describes herniation of brain matter in and around the middle cranial fossa across the greater sphenoid wing and can be ascending or descending. Compression of structures against the sphenoid bone results in symptoms. Pathology Transalar herniation is not...
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Transcallosal approach

Interhemispheric transcallosal approach is a common access route for surgery on the bodies of the lateral ventricles, and third ventricle, which does not lead to serious neurological deficits. It is therefore used for resection of intraventricular tumors such as: central neurocytomas choroid p...
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Transependymal edema

Transependymal edema, also known as interstitial cerebral edema, is a type of cerebral edema that occurs with increased pressure within the cerebral ventricles. FLAIR is the most sensitive MRI sequence for detection. Pathology The ventricular ependymal lining is eventually disrupted, allowing ...
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Transforaminal nerve root injection

Transforaminal nerve root injfection is performed for radicular pain treatment and diagnosis. See spinal interventional procedures for complications and equipment. cervical spine thoracic spine lumbar spine The desired needle tip position is just lateral to the pedicle immediately below the...
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Transient global amnesia

Transient global amnesia (TGA) is a clinical syndrome with no clear etiology identified. Most symptoms are transient and resolve within a few hours.  Epidemiology Most common in patients of older age (50-70 years old). Clinical presentation Anterograde and partial retrograde amnesia lasting ...
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Transient ischemic attack

Transient ischemic attacks (TIAs), in the most recent definition, correspond to a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction. Terminology  In the past, TIA was arbitrarily distinguished from stroke by the dura...
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Transition zone

The transition zone of a nerve describes a region of a few millimetres where the myelin sheath changes from central to peripheral type. This zone is susceptible to mechanical irritation and is implicated in neurovascular compression syndromes such as trigeminal neuralgia (CN V), hemifacial spasm...
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Transmantle sign (brain)

The transmantle sign is an MRI feature of focal cortical dysplasia (FCD), almost exclusively seen in type II focal cortical dysplasia (Taylor dysplasia - also known as transmantle cortical dysplasia for this reason). However, it is not always present, seen in ~45% (range 21-72%) of patients with...
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Transsphenoidal hypophysectomy

Transsphenoidal hypophysectomy is a commonly used surgical approach for pituitary region masses, with many significant advantages over open craniotomy.  History The transsphenoidal approach was first described in 1907 by Schloffer, modified by Halstead and subsequently popularised by Harvey Cu...
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Trans-sphenoidal basilar skull fracture

Trans-sphenoidal basilar skull fractures are a particularly serious type of basilar skull fracture usually occurring in the setting of severe traumatic brain injury and with potential for serious complications including damaging the internal carotid arteries and optic nerves as well as high inci...
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Transtentorial herniation

Transtentorial herniation is a type of cerebral herniation. There are two types: descending transtentorial herniation, more frequently known as uncal herniation ascending transtentorial herniation, which is less common than uncal herniation
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Transverse myelitis

Acute transverse myelitis (ATM) is an inflammatory condition affecting both halves of the spinal cord and associated with rapidly progressive motor, sensory, and autonomic dysfunction. It is mostly imaged with MRI, which generally shows a long segment (3-4 segments or more) of T2 increased sign...
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Transverse sinus

The transverse sinus is one of the dural venous sinuses and drains the superior sagittal sinus, the occipital sinus and the straight sinus, and empties into the sigmoid sinus which in turn reaches the jugular bulb. The two transverse sinuses arise at the confluence of the three aforementioned s...
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Trapped ventricle

Trapped ventricle, also known as isolated ventricle, is a condition in which there is an obstruction to the entry and exit path of CSF through the ventricle. Clinical presentation The presentation is that of increased intracranial pressure due to expanded trapped ventricle. trapped temporal h...
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Traumatic brain injury

Traumatic brain injuries (TBI) are common and come with a large cost to both society and the individual. Imaging, particularly CT, plays a key role in accurate diagnosis, classification and follow-up.  They can be broadly divided into closed and penetrating head injuries 4: closed head injury ...
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Traumatic spinal cord injury

Traumatic spinal cord injury can manifest as a wide variety of clinical syndromes resulting from damage to the spinal cord or its surrounding structures. It can result from minor injury if the spine is weakened from disease such as ankylosing spondylitis or if there is pre-existing spinal stenos...
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Traumatic subarachnoid hemorrhage

Traumatic subarachnoid hemorrhage (tSAH) is a common injury, and trauma is the most common cause of subarachnoid hemorrhage (SAH).  Epidemiology Traumatic subarachnoid hemorrhage occurs in ~35% (range 11-60%) of traumatic brain injuries 1.  Pathology Traumatic subarachnoid hemorrhage is most...
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Triangle of Guillain and Mollaret

The triangle of Guillain and Mollaret, also known as the dentatorubro-olivary pathway, has three corners 1: red nucleus inferior olivary nucleus contralateral dentate nucleus Rubro-olivary fibers descend from the parvocellular division of each red nucleus along the central tegmental tracts t...
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Trident sign (osmotic demyelination)

The trident sign describes the typical appearances of the pons in osmotic demyelination syndrome, whereby the symmetrical high T2/FLAIR signal abnormality centrally in the pons is shaped like a trident, the three-pronged spear of classical Greece 1. The predominant involvement of the transverse ...
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Trident sign (persistent trigeminal artery)

The trident sign of a persistent primitive trigeminal artery refers to the appearance of the intracranial circulation on lateral projection. The internal carotid artery, the abnormal vessel and superior portion of the basilar artery resemble the Greek letter tau (thus tau sign). This configurati...
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Trigeminal autonomic cephalalgias

Trigeminal autonomic cephalalgias are a group of related unilateral headache syndromes with pain and autonomic activation n the trigeminal nerve distribution 1.  The headache syndromes considered to be trigeminal autonomic cephalalgias include 1: cluster headache paroxysmal hemicrania short-...
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Trigeminal nerve

The trigeminal nerve is the fifth cranial nerve and its primary role is relaying sensory information from the face and head, although it does provide motor control to the muscles of mastication. It is both large and complicated and has multiple brainstem nuclei (sensory and motor) as well as man...
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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 standing: superior orbital fissure (ophthalmic division of trigeminal nerve) room: foramen rotundum (maxillary division of trigeminal nerve...
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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 acoustic schwannoma, and has a predominantly benign growth.  Epidemiology  Patients usually present in middle age, typic...
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Trigone of the lateral ventricle

The trigone of of lateral ventricle, also known as the atrium, is a triangular area at the floor of the lateral ventricle that forms the transition point between the occipital and temporal horns. It is the classic location for intraventricular meningioma.
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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 an acoustic 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 with...
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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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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 - 2018) 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 complication. Clinical presentation Small case serie...
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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') metastasises 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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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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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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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, 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 unresponsive to light, signifying...
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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 is the innermost part of the anterior parahippocampal gyrus, part of 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 of the olfactory sys...
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Unverricht-Lundborg disease

Unverricht-Lundborg disease (ULD or EPM1) inherited neurodegenerative disorder which often results in myoclonic epilepsy. Epidemiology It is considered the most common single cause of progressive myoclonus epilepsy worldwide.   Pathology Genetics It carries an autosomal recessive inheritanc...
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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. UE is often associated with lethargy and confusion in the acute phase, which can progress to seizures, coma, or both in the chronic phase...
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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 ...
Article

Valproate-induced hyperammonaemic encephalopathy

Valproate-induced hyperammonaemic encephalopathy (VHE), also known as valproic acid-induced hyperammonaemic encephalopathy, is a rare type of non-cirrhotic hyperammonaemic encephalopathy caused by use of sodium valproate, a drug commonly used as an anti-epileptic and mood stabiliser. Epidemiolo...
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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 meningoenc...
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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 BBB is intact). It is an extracellular edema which mainly affects the white matter via leakage of fluid from capillaries. It is most frequentl...
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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 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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