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.

1,984 results found
Article

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 ...
Article

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...
Article

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...
Article

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...
Article

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 dura...
Article

Transient lesion of the splenium

Transient lesions of the splenium of the corpus callosum, also known as mild encephalitis/encephalopathy with a reversible isolated SCC lesion (MERS), are occasionally encountered on MRI studies and may be due to a number of underlying aetiologies. Clinical presentation Unlike other causes of ...
Article

Transmantle sign (brain)

The transmantle sign is an MRI feature of focal cortical dysplasia, 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 type ...
Article

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...
Article

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
Article

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...
Article

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...
Article

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...
Article

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 ...
Article

Traumatic spinal cord injury

Traumatic spinal cord injury (SCI) 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 ...
Article

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 ...
Article

Triangle of Guillain and Mollaret

The triangle of Guillain and Mollaret, also known as dentatorubro-olivary pathway, has three corners 1: red nucleus inferior olivary nucleus contralateral dentate nucleus Connecting fibres are only identified between the red nucleus and inferior olivary nucleus (central tegmental tract) and ...
Article

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...
Article

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...
Article

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...
Article

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 ...
Article

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...
Article

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. ...
Article

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...
Article

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...
Article

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
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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...
Article

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

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

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...
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...
Article

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 su...
Article

Ulegyria

Ulegyria refers to a shrunken and flattened cortex due to global hypoxic ischaemic 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 ischaemic damage. It is one of t...
Article

Uncal herniation

Uncal herniation is a subtype of transtentorial downward brain herniation, usually related to cerebral mass effect increasing the intracranial pressure. Clinical presentation Abnormal posture and poor GCS. There may be pupillary dilation and loss of light reflex due to direct compression of th...
Article

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 brain asymmetr...
Article

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...
Article

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...
Article

Upper T sign

The upper T sign is one of the features useful in identifying the central sulcus 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 sulcus is the next posterio...
Article

Uraemic encephalopathy

Uraemic encephalopathy (UE) is an acquired toxic syndrome characterised 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 phas...
Article

US carotids (summary)

US carotids is a standard test performed in the assessment of cranial arterial blood supply. Reference article This is a summary article; we do not have a more in-depth reference article. Summary indications (acute) assessment of carotid stenosis TIA/stroke important pathology carotid st...
Article

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...
Article

Vagus nerve

The vagus nerve is the tenth 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 the ...
Article

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...
Article

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...
Article

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...
Article

Vascular dementia

Vascular dementia, also known as vascular cognitive impairment, is the second most common cause of dementia after the far more common Alzheimer's disease. It is primarily seen in patients with atherosclerosis and chronic hypertension and results from the accumulation of multiple white matter or ...
Article

Vasculopathies caused by varicella zoster virus

Vasculopathies caused by varicella zoster virus (VZV) represent a group of illness involving both small and large CNS arteries caused by a inflammatory process involving the media and the vascular endothelium, usually in immunocompromised individuals due the viral reactivation and spread thought...
Article

Vasogenic cerebral oedema

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

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...
Article

Vein of Galen aneurysmal malformation

Vein of Galen aneurysmal malformations (VGAM's), probably better termed as median prosencephalic arteriovenous fistula, 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...
Article

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 and ...
Article

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...
Article

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 ...
Article

Venous vascular malformation of the facial nerve

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

Ventral cord herniation

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

Ventricular system

The ventricular system in the brain is composed of CSF-filled ventricles and their connecting foraminae. CSF is produced by ependymal cells which line the ventricles. They are continuous with the central spinal canal. Ventricles contain around 1/5 of normal adult CSF volume, which is around 20-2...
Article

Ventriculitis

Ventriculitis refers to inflammation, usually due to infection, of the ependymal lining of the cerebral ventricles. It is most often due to intraventricular rupture of brain abscess. Epidemiology Its epidemiology is varied and depends on the underlying cause.  meningitis (both pyogenic and vi...
Article

Ventriculoatrial shunt

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

Ventriculomegaly

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

Ventriculoperitoneal shunt

Ventriculoperitoneal (VP) shunts are a device used in the treatment of non-obstructive hydrocephalus. As the name suggests, a catheter is placed in the ventricle, and another catheter travels under the skin to opens into the peritoneal cavity, both the catheters being connected to each other th...
Article

Ventriculopleural shunt

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

Ventriculus terminalis

The ventriculus terminalis, also known as the 5th ventricle, is an ependymal-lined, anatomical remnant, positioned at the transition from the tip of the conus medullaris to the origin of the filum terminale.  It represents the canalization and retrogressive differentiation of the caudal end of ...
Article

Venus necklace

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

Vermis

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

Verocay bodies

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

Vertebral artery dissection

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

Vertebral artery thrombosis

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

Vertebral scalloping

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

Vidian nerve

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

Viking helmet appearance

The viking helmet appearance refers to the lateral ventricles in coronal projection in patients with dysgenesis of the corpus callosum. The cingulate gyrus is everted into narrowed and elongated frontal horns.  An alternative name is moose head appearance. 
Article

Viral encephalitides

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

Viral meningitis

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

Visual agnosia

Visual agnosia is a special type of agnosia where patients are unable to recognize objects despite having knowledge about them and being able to visually perceive them. It typically occurs when there is damage to the ventral occipito-temporal pathway, such as in posterior cerebral atrophy (Bens...
Article

Visual hallucinations

Visual hallucinations are relatively uncommon, and can be due to a variety of 'organic' brain diseases, affecting a variety of regions of the brain.  The use of the term organic here is by convention, and should not be taken to imply absence of brain dysfunction in psychiatric illness Clinic...
Article

Visual pathway deficits

Visual pathway deficits are determined by the location of the lesion or pathology. Understanding of the visual system is paramount and provided the globe is normal, the field defects can be defined from anterior to posterior as: unilateral central scotoma optic nerve bitemporal hemianopsia o...
Article

Visual system

The visual system transmits visual information from the retina within the eyes to the primary visual cortex of the occipital lobe as well as the pretectal nuclei and superior colliculi of the midbrain. Gross anatomy Below the visual pathway is described from distal to proximal in a single hemi...
Article

Vitamin B1

Vitamin B1 (thiamine) is a water soluble vitamin that is an important coenzyme for two reactions in the citric acid cycle (Kreb’s cycle). It therefore is vital for cellular ATP production, particularly in the central nervous system. Related pathology Pathological manifestations only occur with...
Article

Vitamin B3

Vitamin B3 (niacin or nicotinic acid) is a water soluble vitamin that is an important part of the coenzyme nicotinamide adenine dinucleotide (NAD+) which is involved in many reactions of cellular metabolism. Related pathology Pathological manifestation occur in niacin deficiency known as pella...

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.