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.

2,505 results found
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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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Toxic leukoencephalopathy (mnemonic)

Toxic leukoencephalopathy has myriad causes, the more common of which can be remembered with an acronymic mnemonic: CHOICES​ 1 See the main article for details: toxic leukoencephalopathy. Mnemonic C: chemotherapy H: heroin O: other opioids I: immunosuppressant medication or imidazole C: ...
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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, as these represent the most common brain lesions with mass effect in this population. As treatment is substantially different, distinguishing the two on imaging is important, particularly when the lesion ...
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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 pseudotumor perioptic neuritis orbital sarcoidosis orbital leukemia orbital lymphoma orb...
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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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Transcranial Doppler sonography (ultrasound)

Transcranial​ ​Doppler​ ​(TCD)​, also known as transcranial color-coded duplex sonography (TCCS) is a sonographic study of intracranial structures and blood vessels, used most commonly to identify the hemodynamic state present in the vertebrobasilar circulation and the circle of Willis.  Termin...
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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 epidural steroid injection

Transforaminal epidural steroid injections (TFESI), also known as transforaminal nerve root injection or nerve root blocks, are performed for treatment and diagnosis of radicular pain. They differ from selective nerve root blocks (SNRB), as the aim is to get "epidural spill" and get the injectat...
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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 (disambiguation)

Transition zone may refer to the: transition zone of a nerve zone of transition of a bone lesion transition zone (TZ) of the prostate
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Transition zone (nerve)

The transition zone of a nerve describes a region of a few millimeters 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 popularized by Harvey Cu...
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Transsphenoidal basilar skull fracture

Transsphenoidal 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 incid...
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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 fissure

The transverse fissure (of Bichat) is the cerebral fissure that extends laterally from the ambient cistern towards the hippocampus. Gross anatomy The transverse fissure is the lateral extension of the ambient cistern that connects with the choroidal fissure superolaterally and hippocampal fiss...
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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 paired left and right transverse sinuses are major dural venous sinuses and arise from the confluence of the superior sagittal, occipital and straight sinuses at the torcular herophili (confluence of sinuses). On each side, the transverse sinus then runs in the lateral border of the tentori...
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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. The diagnosis of traumatic brain injury is a clinical decision, however, imaging, particularly CT, plays a key role in diagnostic work-up, classification, prognostication and follow-up.  The...
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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 more...
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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 appearance (disambiguation)

The trident appearance (or sign) can refer to a variety of entities: trident acetabulum trident hand trident sign (osmotic demyelination) trident sign (persistent trigeminal artery) History and etymology The trident is a three-pronged lance employed for spearing fish, and in Classical myth...
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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 primitive 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 ganglion

The trigeminal ganglion, also known as the Gasser, Gasserian or semilunar ganglion, is the large crescent-shaped sensoryganglion of the trigeminal nerve located in the trigeminal cave (Meckel cave) surrounded by cerebrospinal fluid. The ganglion contains the cell bodies of the sensory root of t...
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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 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 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') 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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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, 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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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 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. 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...
Article

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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