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.

2,130 results found
Article

Tay sachs disease

Tay-Sachs disease is a hereditary neurodegenerative disorder resulting from excess storage of GM2 ganglioside within the lysosomes of cells.  Epidemiology The incidence of the disease is estimated to be 1 in 3600 in Ashkenazi Jews with carrier frequency of 1 in 30 and 1 in 360,000 in other pop...
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Technetium agents

Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. The radioactive technetium radiotracer can be chelated to a number of different compounds to create specific radiopharmaceuticals and optimise the functional imaging of various stru...
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Tectal beaking (midbrain)

Tectal beaking refers to the fusion of the midbrain colliculi into a single beak pointing posteriorly and invaginating into the cerebellum. It is seen with a Chiari type II malformation. Terminology The term bird beak sign is used in a number of other contexts: see bird beak sign (disambiguati...
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Tectal glioma

Tectal gliomas fall under the grouping of childhood brainstem gliomas and unlike the other tumours in that group they are typically low grade astrocytomas with good prognosis.  Epidemiology Tectal plate gliomas are encountered in children and adolescents 4. A male predilection has sometimes be...
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Tegmentovermian angle

The tegmentovermian angle is an important measurable parameter in the assessment of posterior fossa abnormalities in the fetus. The angle is constructed on midsagittal images of the fetal brain, ideally on MRI. The angle is formed by the intersection of the following two lines 1: line 1: along...
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Tegmentum

The tegmentum (Latin: "hood") is one of the areas of the brainstem. It is a phylogenetically old part of the brainstem and in adults, is the location of the brainstem nuclei.  In the midbrain, it sits between the quadrigeminal plate and cerebral peduncles. In the pons, it is posterior to the ba...
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Tela choroidea

The tela choroidea is the thin, highly vascularised, loose connective tissue portion of pia mater that gives rise to the choroid plexus. Thus, it is basically the lamina propria of the ependyma and lies directly adherent to it, without any tissue in between the two 6. Gross anatomy Being part ...
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Temporal bone destructive lesions (differential)

Destructive lesions of the temporal bone (petrous pyramid, middle ear and antrum) have a relatively broad differential including 1: lesions affecting petrous pyramid acoustic schwannoma meningioma glioma neuroma of trigeminal and facial nerve chordoma glomus jugulare tumour epidermoid of...
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Temporal bone fracture

Temporal bone fracture is usually a sequela of significant blunt head injury. In addition to potentially damage to hearing and the facial nerve, associated intracranial injuries, such as extra-axial haemorrhage, diffuse axonal injury and cerebral contusions are common. Early identification of te...
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Temporal lobe

The temporal lobe is one of the four lobes of the brain (along with the frontal lobe, parietal lobe, and occipital lobe), and largely occupies the middle cranial fossa. Gross anatomy The temporal lobe is the second largest lobe, after the larger frontal lobe, accounting 22% of the total neocor...
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Temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is the most common type of partial epilepsy, with often characteristic imaging and clinical findings. It is divided into two broad groups: medial epilepsy most common involves the mesial temporal lobe structures most frequently due to mesial temporal sclerosis l...
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Temporal pole

The temporal pole is an anatomical landmark that corresponds to the anterior end of the temporal lobe, lying in the middle cranial fossa.  It corresponds to Brodmann area 38 and has strong connections with the amygdala and orbital prefrontal cortex, and is sometimes recognised as a component of...
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Temporopolar artery

The temporopolar artery is usually a dorsolateral branch from the M1 segment of the middle cerebral artery (MCA) and supplies the polar and anterolateral portions of the temporal lobe.  This artery may arise as a branch from the anterior temporal artery 1.  
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Tension pneumocephalus

Tension pneumocephalus is a neurosurgical emergency that occurs when subdural air causes a mass-effect over the underlying brain parenchyma, often from a ball-valve mechanism causing one-way entry of air into the subdural space 1. Clinical features Tension pneumocephalus has a varied clinical ...
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Tentorial angle

The tentorial angle is measured between a line connecting the nasion with the tuberculum sellae and the the angle of the straight sinus. Normally it should measure between 27° and 52°. Abnormalities of the posterior fossa / base of skull can alter this. For example this angle is elevated in ach...
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Tentorium cerebelli

The tentorium cerebelli is the second largest dural fold after the falx cerebri. It lies in the axial plane attached perpendicularly to the falx cerebri and divides the cranial cavity into supratentorial and infratentorial compartments 1. It contains free and attached margins 2. Gross anatomy ...
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Terminal myelocystocele

Terminal myelocystoceles are an uncommon form of spinal dysraphism representing marked dilatation of the central canal of the spinal cord, herniating posteriorly through a dorsal spinal defect. The result is a skin-covered mass in the lower lumbar region, consisting of an ependyma-lined sac.  E...
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Terminal zones of myelination

The terminal zones of myelination are located at the posterior aspect of the lateral ventricles (the peritrigonal regions) and are the only part of the cerebral white matter that may exhibit high T2 signal in a normal brain at 2 years of age, when myelination of cerebral white matter normally be...
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Terson syndrome

Terson syndrome refers to vitreous haemorrhage associated with subarachnoid haemorrhage, however some authors include retinal haemorrhage as well. The syndrome is a poor prognostic marker in patients with subarachnoid haemorrhage. Epidemiology Terson syndrome has been reported to occur in 13-5...
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TERT promoter mutations

TERT promoter mutations affect the TERT promoter (located on the short arm of chromosome 5) which encodes for the hTERT component of telomerase, an enzyme which maintains and lengthens telomeres 1. Mutations that result in enhanced activity of telomerase, and therefore longer telomeres, can be i...
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Tethered cord

Tethered spinal cord syndrome, also known as an occult spinal dysraphism sequence, is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column. Clinical presentation The condition is closely linked to spina bifida, and as such pre...
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Thalamencephalon

The thalamencephalon is an anatomic region that includes the thalamus, metathalamus and epithalamus. It is one of the components that form the diencephalon.
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Thalamic haemorrhage

Thalamic haemorrhages or thalamic haemorrhagic strokes are often the result of chronic hypertension. The thalamus transmits or prevents transmission of sensory signals from sensory areas of the cerebral cortex through internal capsule fibres and has a role in memory thus the clinical presentatio...
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Thalamostriate veins

Thalamostriate veins are formed by the joining of anterior caudate vein and the vein of stria terminalis. They join the septal veins and form internal cerebral veins. Related pathology The thalamostriate veins can be compressed in preterm neonates who have had germinal matrix haemorrhage. This...
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Thalamus

The thalamus is the largest of the structures comprising the diencephalon. Role The thalamus acts as a relay centre, receiving and distributing information between the peripheries and higher centres such as the cerebral cortices. It contributes to functions such as: consciousness sleep memo...
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Thallium-201 chloride

Thallium-201 chloride is a radiopharmaceutical used primarily in cardiac imaging. Characteristics photon energy: 80 keV physical half life: 73 hours biological half life rest: 3 minutes exercise: 30 seconds normal distribution: myocardium, skeletal muscle, GI tract, liver, kidneys excret...
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Third ventricle

The third ventricle is one of the four CSF-filled cavities that together comprise the ventricular system. Gross anatomy The third ventricle is a median cleft between the two thalami and is bounded laterally by them and the hypothalamus. Its anterior wall is formed by the lamina terminalis, and...
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Third ventriculostomy

A third ventriculostomy is a type of surgical treatment for obstructive hydrocephalus, especially when obstruction is located at the level of the aqueduct of Sylvius (e.g. aqueduct stenosis). A permanent defect is created in the floor of the third ventricle anterior to the mammillary bodies, thu...
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Thrombolysis in cerebral infarction (TICI) scale

The thrombolysis in cerebral infarction (TICI) grading system was described in 2003 by Higashida et al. 1 as a tool for determining the response of thrombolytic therapy for ischaemic stroke. In neurointerventional radiology it is commonly used for patients post endovascular revascularisation. Li...
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Thumb sign (chordoma)

The thumb sign or thumbing of the pons is described in chordomas as is meant to be relatively specific. It is seen in midline sagittal projection as a projection of the tumour indenting the pons 1,2. See also thumb sign (disambiguation)
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Thyroid-associated orbitopathy

Thyroid-associated orbitopathy (TAO) is the most common cause of proptosis in adults and is most frequently associated with Graves disease. On imaging, it is characterised by enlargement of the extraocular muscles' bellies (frequently: inferior rectus > medial rectus  > superior rectus) sparing...
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Tiger stripe appearance

The tiger stripe appearance refers to the characteristic alternating hypo and hyperintense bands on MRI in Lhermitte-Duclos disease. This rare cerebellar tumour appears like the coat of a tiger. See also tigroid pattern - in brain
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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 ischaemic stroke. large-artery atherosclerosis (embolus / thrombosis)* cardioembolism (high-risk / medium-risk)* small-vessel occlusion (lacune)* stroke of other determined aetiology * stroke o...
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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 ischaemic stroke presenting with a seizure.   Epidemiology The incidence of Todd para...
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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 characterised 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 ischaemia due to occlusion of perforator vessels. Clinical presentation Clinically, top of the basilar syn...
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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 paediatric 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

It is a relatively common occurrence for radiologists to be asked to distinguish between cerebral toxoplasmosis and primary CNS lymphoma (PCNSL) in patients with HIV/AIDS. Treatment is clearly different and thus accurate interpretation of CT and MRI is essential. In many instances appearances a...
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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 tumours such as: central neurocytomas choroid ...
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Transependymal oedema

Transependymal oedema, also known as interstitial cerebral oedema, is a type of cerebral oedema that occurs with increased pressure within the cerebral ventricles. FLAIR MRI sequence is the most sensitive MRI sequence to detect this type of oedema. Pathology The ventricular ependymal lining is...
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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 aetiology 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 ischaemic attack

Transient ischaemic attack (TIA), in the most recent definition, corresponds to a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction. Terminology  In the past, TIA was arbitrarily distinguished from stroke by the dur...
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Transition zone

The transition zone of a nerve describes a roughly 2 mm length region 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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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 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 haemorrhage

Traumatic subarachnoid haemorrhage (tSAH) is a common injury, and trauma is the most common cause of subarachnoid haemorrhage (SAH).  Epidemiology Traumatic subarachnoid haemorrhage occurs in ~35% (range 11-60%) of traumatic brain injuries 1.  Pathology Traumatic subarachnoid haemorrhage is ...
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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 fibres descend from the parvocellular division of each red nucleus along the central tegmental tracts t...
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Trident sign (CNS)

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 trident is most commonly associated with 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 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 tumours 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, typi...
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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 tumours. 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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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 differentiating between one and other cerebellopontine angle entities, especially from a meningioma which typically does not extend into the meatus 1. It is characterized by widenin...
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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 (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 characterised by cerebral oedema 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 as tuberculous pachymeningitis and is discussed separately.  The rema...
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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 characterised 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...
Article

Tuberous sclerosis

Tuberous sclerosis (TS), also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterised by the development of multiple benign tumours of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosis has...
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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 been adapted from Roach et al 1998 1: definitive TS complex: either 2 major features or 1 major and 2 minor probable TS complex: 1 major and 1 minor possible TS complex: either 1...
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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 recognise 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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Tumour pseudoprogression

Tumour 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 tumours imaging follow-up, especially for high grade gliomas (e.g. glioblastoma), and is observed...
Article

Tumour pseudoresponse

Tumour pseudoresponse, also known just as pseudoresponse, refers to the phenomenon of tumours 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 tumours imaging follow-up, especially...
Article

Tumours of the meninges (differential)

Tumours 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 tumours, the main entities to be considered include:  meningioma and nume...
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Tumour-to-tumour metastasis

A tumour-to-tumour metastasis, also known as a collision tumour, is a rare metastatic process in which a primary malignant tumour ('donor') metastasises to another tumour ('recipient'), most commonly a benign tumour such as a meningioma. Epidemiology Tumour-to-tumour metastasis is considered v...
Article

Turcot syndrome

Turcot syndrome is one of the variations in polyposis syndromes. Epidemiology Patients typically present in the second decade 3. Pathology Turcot syndrome  is characterised by: intestinal polyposis CNS tumours: most commonly glioblastoma or medulloblastoma Genetics It is thought to carry...
Article

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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