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.
2,649 results found
Article
Anterior cerebral artery (ACA) infarct
Anterior cerebral artery (ACA) territory infarcts are much less common than either middle or posterior cerebral artery territory infarcts.
Epidemiology
ACA territory infarcts are rare, comprising ~2% of ischemic strokes 1,2.
Clinical presentation
ACA stroke syndrome presents as 1-3:
dysarth...
Article
Anterior choroidal artery
The anterior choroidal artery (AChA) supplies several crucial anatomical structures of the brain important for vision and motor control. Identification of AChA is important because of its strategic and extensive area of supply as well as large variations in the territorial distribution.
Gross a...
Article
Anterior choroidal artery syndrome
Anterior choroidal artery syndrome is a rare entity characterized by the triad of
hemiplegia
hemianaesthesia and
contralateral hemianopia
This occurs as a result of cerebral infarction in the anterior choroidal artery territory.
The syndrome may also be associated with neuropsychological di...
Article
Anterior cingulate cortex
The anterior cingulate cortex (ACC), previously known as the precingulate, is a region of the brain surrounding the anterior corpus callosum. It is involved in the limbic system and the prefrontal cortex.
Summary
location: it is located superior to the anterior corpus callosum, more specifical...
Article
Anterior circulation
The anterior circulation is the blood supply to the anterior portion of the brain, including most of the supratentorial structures excluding the occipital lobes.
The anterior circulation is supplied by the internal carotid arteries which each divide into two the large terminal branches, the ant...
Article
Anterior commissure
The anterior commissure (AC) is a transversely oriented commissural white matter tract that connects the two cerebral hemispheres along the midline. It is a very important anatomical landmark that connects different parts of the limbic system on both sides and plays a role in the interhemispheri...
Article
Anterior commissure - posterior commissure line
The anterior commissure - posterior commissure line (AC-PC line), also known as the bicommissural line, has been adopted as a convenient standard by the neuroimaging community, and in most instances is the reference plane for axial imaging in everyday scanning. The creation of a standard image p...
Article
Anterior communicating artery
The anterior communicating artery (ACOM) arises from the anterior cerebral artery and acts as an anastomosis between the left and right anterior cerebral circulation. Approximately 4 mm in length, it demarcates the junction between the A1 and A2 segments of the anterior cerebral artery.
Branche...
Article
Anterior condylar confluence
The anterior condylar confluence is an extracranial venous structure at the base of skull that communicates extensively with regional veins and dural venous sinuses.
It is located immediately anterior to the hypoglossal canal and medial to the jugular vein, just inferior to the jugular bulb an...
Article
Anterior corticospinal tract
The anterior corticospinal tract is formed at the level of the of the medullary pyramids, where the majority (90%) of descending corticospinal tract fibers decussate to form the lateral corticospinal tract. The majority of the remaining non-decussating 10% of fibers form the much smaller anterio...
Article
Anterior epitympanic recess
The anterior epitympanic recess, also known as the supratubal recess, is a small discrete space in the epitympanum anterior to the malleus. It is separated from the epitympanum proper by the cog.
Article
Anterior ethmoidal foramen
The anterior ethmoid foramen is a small opening in the ethmoid bone. It is the anatomical border of anterior and posterior ethmoid air cells. It transmits the anterior ethmoidal artery, vein and nerve.
The anterior ethmoid foramen is situated 25 mm away from the lacrimal crest, 12 mm anterior t...
Article
Anterior ethmoidal nerve
The anterior ethmoidal nerve is an extraconal branch of the nasociliary nerve, a branch of the ophthalmic division of the trigeminal nerve. Some authors describe it as either the terminal branch or a direct continuation of the nasociliary nerve. It branches off distal to the infratrochlear nerv...
Article
Anterior fontanelle
The anterior or frontal fontanelle is the diamond-shaped soft membranous gap (fontanelle) at the junction of the coronal and sagittal sutures. It persists until approximately 18-24 months after birth, after which it is known as the bregma. The precise timing of the anterior fontanelle closure is...
Article
Anterior horn syndrome
Anterior horn syndrome is a fairly generic term used to refer to flaccid paralysis and areflexia due to involvement of the anterior grey matter horns of the spinal cord. Sensation is typically preserved.
Causes of anterior horn syndrome include:
anterior spinal artery ischemia
poliomyeliti...
Article
Anterior inferior cerebellar artery
The anterior inferior cerebellar artery (AICA) is one of three vessels that provides arterial blood supply to the cerebellum. It has a variable origin, course and supply, with up to 40% of specimens not having an identifiable standard AICA. The amount of tissue supplied by the AICA is variable (...
Article
Anterior inferior cerebellar artery (AICA) infarct
Anterior inferior cerebellar artery (AICA) territory infarcts are much less common than posterior inferior cerebellar artery (PICA) infarcts. AICA generally arises from the caudal third of the basilar artery and supplies the lateral pons, inner ear, middle cerebellar peduncle and the anterior in...
Article
Anterior meningocele
Anterior meningocele is characterized by herniation of CSF-filled sac through a sacral anterior osseous defect. It is consistently found in the caudal regression syndrome.
It is in continuity with the thecal sac and lined by arachnoid and dura mater, but does not contain neural tissue.
Contrar...
Article
Anterior perforated substance
The anterior perforated substance, or substantia perforata anterior, is an area in the basal forebrain that plays an important role with regards to the blood supply of deep grey matter structures of the brain.
Gross anatomy
Located within the basal forebrain, the anterior perforated substance...
Article
Anterior pituitary
The anterior pituitary (or adenohypophysis) is by far the largest part of the pituitary gland, and is responsible for synthesis and release of most pituitary hormones (with the exception of oxytocin and antidiuretic hormone (ADH) which are released by the posterior pituitary).
It consists of 3 ...
Article
Anterior pontine membrane
The anterior pontine membrane is an arachnoid membrane located anteriorly in the posterior fossa to the side of the basilar artery, separating the prepontine cistern (medially) form the cerebellopontine cistern (laterally) 1.
The abducens nerve (CN VI) travels within the membrane as it ascends...
Article
Anterior ramus of the lateral sulcus
The anterior ramus of the lateral sulcus, is located at the very anterior end of the lateral sulcus (sylvian fissure), just anterior to the ascending ramus, and passes superiorly into the inferior frontal gyrus separating the pars orbitalis form the pars triangularis of the frontal operculum.
...
Article
Anterior sacral meningocele
Anterior sacral meningocele is a congenital defect seen in the anterior aspect of the spine. It is defined as a meningeal cyst that occurs in the presacral space secondary to agenesis of a portion of the anterior sacrum.
Pathology
Associations
In approximately 50% of cases, associated malform...
Article
Anterior spinal artery
The anterior spinal artery supplies the anterior portion of the spinal cord and arises from the vertebral artery in the region of the medulla oblongata. The two vertebral arteries (one of which is usually bigger than the other) anastamose in the midline to form a single anterior spinal artery at...
Article
Anterior spinal commissure
The anterior spinal commissure connects the left and right sides of the spinal cord anteriorly. It is located between the posterior-most extent of the anterior median fissure anteriorly and the ventral grey matter commissure posteriorly 1.
It is composed of anterior and lateral spinothalamic t...
Article
Anterior spinothalamic tract
The anterior spinothalamic tract, also known as the ventral spinothalamic fasciculus, is an ascending pathway located anteriorly within the spinal cord, primarily responsible for transmitting coarse touch and pressure.
The lateral spinothalamic tract (discussed separately), in contrast, primar...
Article
Anterior temporal artery
The anterior temporal artery is usually a branch of the M1 segment of the middle cerebral artery (MCA) that curves out of the Sylvian fissure and runs over the temporal lobe to supply the anterior third of the superior, middle and inferior temporal gyri.
Variant anatomy
The temporopolar arter...
Article
Anterior temporal lobe perivascular spaces
Anterior temporal lobe perivascular spaces are recently recognized special variants of tumefactive perivascular spaces, which can mimic cystic tumors with surrounding edema.
Epidemiology
A predilection for women has been reported 1. Age range is wide, from 24 to 86 years old reported 1.
Clini...
Article
Anthrax
Anthrax is a zoonosis caused by Bacillus Anthracis. There are four types of anthrax: inhalational anthrax (also known as woolsorter's disease and ragsorter's disease), cutaneous anthrax, injection anthrax and intestinal anthrax.
Epidemiology
The disease burden of anthrax decreased so dramatica...
Article
Anti-GQ1b IgG antibody syndrome
Anti-GQ1b IgG antibody syndrome refers to a number of conditions which share autoantibodies to the ganglioside complex GQ1b, and have overlapping clinical spectrums.
The conditions believed to represent various clinical manifestations of a common immunological disorder include 1:
acute ophth...
Article
Anti-MOG associated encephalomyelitis
Anti-MOG associated encephalomyelitis represents a group of inflammatory demyelinating disorders united by the presence of IgG antibodies to myelin oligodendrocyte glycoprotein (MOG) that overlap but are distinct from acute disseminated encephalomyelitis (ADEM), neuromyelitis optica spectrum dis...
Article
Anti-N-methyl-D-aspartic acid receptor encephalitis
Anti N-methyl-D-aspartic acid (NMDA) receptor encephalitis is an autoimmune encephalitis with antibodies against the NMDA receptors. It is sometimes considered a form of autoimmune limbic encephalitis. It usually affects young patients particularly young females, in about 60% of whom ovarian ter...
Article
Antiphospholipid syndrome
Antiphospholipid syndrome is a systemic autoimmune disorder. It is usually defined as the clinical complex of vascular occlusion and ischemic events occurring in patients who have circulating antiphospholipid antibodies.
Clinical presentation
Antiphospholipid syndrome is characterized by venou...
Article
Antonio Egas Moniz
Antonio Egas Moniz (1874-1955) 1 was a pioneering Portuguese neurologist that is notable in radiology history for his development of cerebral angiography in 1927.
He is also known as the developer of prefrontal leucotomy (now better known as a lobotomy) for which he received a Nobel Prize in 1...
Article
Aphakia
Aphakia (less commonly aphacia) is the absence of the lens from the ocular globe.
Pathology
Etiology
surgical removal of a cataract (commonest cause)
trauma
congenital
Treatment and prognosis
Surgical insertion of an intraocular lens implant, in which case the aphakic appearance is calle...
Article
Apoplexy
Apoplexy is a term that has been part of medical terminology since antiquity and now means a sudden and catastrophic clinical presentation restricted to a few intracranial events, namely pituitary apoplexy and the far less common pineal apoplexy. Importantly, it remains a term that denotes a cli...
Article
Apraxia
Apraxia is the inability to perform tasks which the patient has previously learned and has no physical impairment which would preclude them from performing them 1.
Typically apraxia stems from damage to the parietal lobes.
Article
Aprosencephaly
Aprosencephaly is an extremely rare anomaly fetal cerebral development the derivatives of the telencephalon as well as the diencephalon are absent or dysplastic, while more caudal structures are normal or mildly deformed. It falls under the aprosencephaly / atelencephaly spectrum (AAS).
See al...
Article
Aquaporin
Aquaporin is a family of transmembrane water channels found throughout the body of both humans and many other species, facilitating the passage of water, cations and gases 1.
At least 13 types of aquaporin have been described, and these are variably expressed.
Aquaporin 4
Aquaporin 4 (gene:...
Article
Aqueduct stenosis
Aqueductal stenosis is the most common cause of congenital obstructive hydrocephalus, but can also be seen in adults as an acquired abnormality.
Epidemiology
Congenital aqueductal stenosis has an estimated incidence of ~1:5000 births although the reported range varies greatly (3.7:1,000,000 t...
Article
Arachnoid cyst
Arachnoid cysts are relatively common benign and asymptomatic lesions occurring in association with the central nervous system, both within the intracranial compartment (most common) as well as within the spinal canal. They are usually located within the subarachnoid space and contain CSF.
On ...
Article
Arachnoid cyst (fetal presentation)
A fetal arachnoid cyst is term given when an arachnoid cyst is diagnosed in utero. For a general discussion of arachnoid cysts refer to the parent article.
Pathology
They can be classified as being primary or secondary 2.
primary (congenital) arachnoid cysts: result from a benign accumulation...
Article
Arachnoid granulation
Arachnoid granulations, also known as Pacchionian granulations, are projections of the arachnoid membrane (villi) into the dural sinuses that allow CSF to pass from the subarachnoid space into the venous system.
Epidemiology
They increase in size and number with age and are seen in approximate...
Article
Arachnoid hyperplasia
Arachnoid hyperplasia refers to an extensive thickening of meninges surrounding optic glioma often seen in patients with neurofibromatosis.
It appears as high signal on T2 sequences surrounding the low signal glioma and resembles perineural CSF space.
Article
Arachnoiditis
Arachnoiditis is a broad term encompassing inflammation of the meninges and subarachnoid space.
Terminology
Arachnoiditis affecting the cauda equina may be referred to as spinal/lumbar adhesive arachnoiditis.
Clinical presentation
Lumbar spine arachnoiditis can result in leg pain, sensory c...
Article
Arachnoid mater
The arachnoid mater forms the middle layer of the meninges and together with the pia mater is sometimes referred to as the leptomeninges.
Gross anatomy
The arachnoid mater is a membrane that comes into direct contact with the dura mater and is separated from the pia mater by a CSF-filled spac...
Article
Arachnoid membranes
Arachnoid membranes represent sheet-like connective tissue that crosses the subarachnoid space, from the pia mater to the arachnoid mater, dividing the subarachnoid space into cisterns. A number of these membranes are named 1:
Liliequist membrane: separates the chiasmatic cistern and interpedun...
Article
Arc sign (CARASIL)
The arc sign has been described in late-stage CARASIL and is seen on axial T2 weighted images. It describes high signal extending from one middle cerebellar peduncle, across the pons, to the contralateral middle cerebellar peduncle 1.
Article
Area postrema
The area postrema, also known as the chemoreceptor trigger zone is one of the so-called circumventricular organs located on the dorsal inferior surface of the medulla oblongata at the caudal end of the fourth ventricle.
The specialized ependymal cells in the area postrema detect toxins in the b...
Article
Argyll Robertson pupil
Argyll Robertson pupil is usually bilateral and presents as bilaterally miotic and irregular pupils, which constrict briskly with accommodation but do not react to bright light therefore displaying light-near dissociation 1.
It is a highly specific sign of late neurosyphilis, however can also ...
Article
Arnold's nerve
Arnold's nerve is the eponymous name of the auricular branch, also known as the mastoid branch, of the vagus nerve (CN X).
Origin and course
Arnold's nerve originates from the superior ganglion of the vagus nerve and also has a small contribution from the inferior ganglion of the glossopharyng...
Article
Arterial spin labeling MR perfusion
Arterial spin labeling (ASL) MR perfusion is an MR perfusion technique which does not require intravenous administration of contrast (unlike DSC perfusion and DCE perfusion). Instead it exploits the ability of MRI to magnetically label arterial blood below the imaging slab. The parameter most c...
Article
Arterial supply of the head and neck
The arteries of the head and neck are branches of the common carotid and subclavian arteries.
common carotid artery
carotid body
carotid bifurcation
internal carotid artery (segments)
caroticotympanic artery
persistent stapedial artery
ophthalmic artery
supraorbital artery
lacrimal arte...
Article
Arterial vasocorona
The arterial vasocorona is part of the spinal cord blood supply and is formed by pial anastomoses between the anterior and posterior spinal arteries on the surface of the spinal cord. It encircles the cord and supplies the peripheral lateral aspect of the spinal cord.
Engorgement of arterial v...
Article
Artery of Adamkiewicz
The artery of Adamkiewicz, also known as the great anterior radiculomedullary artery or arteria radicularis anterior magna, is the name given to the dominant thoracolumbar segmental artery that supplies the spinal cord.
Gross anatomy
Origin
The artery of Adamkiewicz has a variable origin but ...
Article
Artery of Bernasconi and Cassinari
The artery of Bernasconi and Cassinari, also known as medial or marginal tentorial artery (of Bernasconi–Cassinari), commonly arises from the cavernous segment of the internal carotid artery.
Gross anatomy
The artery of Bernasconi and Cassinari is ~2 cm long and is an important branch of the m...
Article
Artery of Percheron
The artery of Percheron is a rare variant of the posterior cerebral circulation characterized by a solitary arterial trunk that supplies blood to the paramedian thalami and the rostral midbrain bilaterally. From the original classification of arterial patterns at the origin of the paramedian art...
Article
Artery of Percheron territory infarct
Artery of Percheron territory infarct is rare, on account of the relative rarity of the artery of Percheron, and presents with a variety of signs and symptoms collectively termed the paramedian thalamic syndrome. It is a type of posterior circulation infarction.
On imaging, it is classically ch...
Article
Ascending ramus of the lateral sulcus
Ascending ramus of the lateral sulcus, is located at the anterior end of the lateral sulcus (sylvian fissure), just posterior to the anterior ramus, and passes superiorly into the inferior frontal gyrus separating the pars triangularis from the pars opercularis of the frontal operculum.
Termin...
Article
Ascending transtentorial herniation
Ascending transtentorial herniation is a situation where space-occupying lesions in the posterior cranial fossa cause superior displacement of superior parts of the cerebellum through the tentorial notch.
Clinical presentation
nausea and/or vomiting
rapid progression toward a decreased leve...
Article
ASCOD classification (ischemic stroke)
The ASCOD classification system 1, published in 2013, aims to define phenotypes of ischemic strokes for individual patients by assigning a degree of probability to each of the most common causes of this pathology.
It serves most strictly as a research tool but is also useful clinically as a mne...
Article
ASIA impairment scale for spinal injury
The American Spinal Injury Association Impairment Scale was developed by the American Spinal Injury Association (ASIA) in 2006, was revised in 2011, and remains the most widely used neurologic classification of spinal cord injury.
Classification
The scale divides spinal cord injuries into 5 ca...
Article
Association fibers of the brain
Association fibers of the brain, also known as association tracts of the brain or intrahemispheric tracts (cortex-cortex connections 1) are a type of white matter tract that connects different areas in the same hemisphere. There are two types of association fibers: long-range and U-fibers (short...
Article
Astroblastoma
Astroblastomas are rare glial tumors usually found in the cerebral hemispheres of young adults and children.
Epidemiology
They occur at all ages range from early childhood to 6th decade but are most commonly seen in children, adolescents, and young adults with a mean age between 10-30 years 2...
Article
Astrocytes
Astrocytes are cells of the central nervous system which act as both physical and physiological support for the neurons that are embedded between them. They are particularly abundant in the grey matter, where they are the most abundant glial cells 1.
They are highly branched and contribute to t...
Article
Astrocytic tumors
Astrocytic tumors are primary central nervous system tumors that either arises from astrocytes or appear similar to astrocytes on histology having arisen from precursor cells. They are the most common tumors arising from glial cells.
They can be divided into those that are diffuse in growth (th...
Article
Astronomical inspired signs
Many signs in radiology have been inspired by astronomical phenomena:
comet tail (disambiguation)
comet tail artifact (ultrasound)
color comet tail artifact
comet tail sign (chest)
comet tail sign (phleboliths)
earth-heart sign
galaxy sign (chest)
loss of half-moon overlap sign
milky wa...
Article
Asymmetrically large jugular bulb
Asymmetrically large jugular bulbs are entirely normal and asymptomatic; its only significance is to distinguish it from pathology.
The size of the jugular bulbs is variable, with the right side being significantly larger than the left in two-thirds of people.
A normal but large bulb will have...
Article
Asymmetric fatty bone marrow of the petrous apex
Asymmetric pneumatization of petrous apex is a frequent normal anatomic variant resulting in asymmetric fatty bone marrow within the petrous apex. It is a common incidental finding on brain and skull base MRI.
Clinical presentation
Asymptomatic.
Pathology
Asymmetric pneumatization of the pet...
Article
Asymmetric ventriculomegaly, interhemispheric cyst and dysgenesis of the corpus callosum (AVID)
Asymmetric ventriculomegaly, interhemispheric cyst, and dysgenesis of the corpus callosum (AVID) is a triad of congenital cerebral anomalies.
Radiographic features
markedly asymmetric enlargement of the lateral ventricles may be the initial finding on routine fetal morphology ultrasound.
inte...
Article
Asymmetry of the lateral ventricles
The lateral ventricles occasionally show small side to side differences in size on CT or MRI of the brain. This asymmetry of the lateral ventricles (ALV) is an anatomic variant in most cases.
Epidemiology
The prevalence of asymmetry in lateral ventricle size in those without evidence of underl...
Article
Ataxia (clinical sign)
Ataxia denotes the impaired coordination of voluntary muscle function. It is not a specific disease, but a clinical sign that can have diverse etiologies. It is typically caused by either cerebellar damage or impaired vestibular or proprioceptive afferent sensory input to the cerebellum.
Clinic...
Article
Ataxia telangiectasia
Ataxia-telangiectasia is a rare multisystem disorder that carries an autosomal recessive inheritance, sometimes classified as a phakomatosis. It is characterized by multiple telangiectasias, cerebellar ataxia, pulmonary infections, and immunodeficiency.
On brain imaging, it usually demonstrate...
Article
Atelencephaly
Atelencephaly (also termed atelencephalic microcephaly) is a rare and extreme disorder with only a handful of published cases. In this anomaly, the derivatives of the telencephalon are absent or dysplastic, while more caudal structures are normal or mildly deformed. It falls under the aprosencep...
Article
Atlantodental interval
The atlantodental interval (ADI) is the horizontal distance between the anterior arch of the atlas and the dens of the axis, used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis.
It is the distance (in mm) between the posterior cortex of the anteri...
Article
Atretic parietal cephalocele
Atretic parietal cephaloceles (APC), also known as atretic cephaloceles, are small subscalp lesions that consist of dura, fibrous tissue, and dysplastic brain tissue.
Epidemiology
Common presentation in infants and young children.
Clinical presentation
Palpable midline parietal soft tissue ...
Article
Atypical callosal dysgenesis
Atypical callosal dysgenesis is a term used to denote an unusual pattern of dysgenesis of the corpus callosum.
The development of the corpus callosum occurs between the 12th and 16-20th weeks of gestation 2-3. It begins with the genu and then continues posteriorly along the body to the splenium...
Article
Atypical choroid plexus papilloma
Atypical choroid plexus papillomas are WHO grade II tumors derived from choroid plexus epithelium with intermediate clinical and pathological features between the much more common, and more indolent, WHO grade I choroid plexus papilloma and the more aggressive WHO III choroid plexus carcinoma.
...
Article
Atypical meningioma
Atypical meningioma refers to a more aggressive form of meningioma and denotes a WHO grade II tumor (along with two histological variants, clear cell meningioma and chordoid meningioma). Atypical meningiomas account for 20-30% of all meningiomas 1,3.
It should be noted that epidemiology, clini...
Article
Atypical teratoid/rhabdoid tumor
Atypical teratoid/rhabdoid tumors (AT/RT) are an uncommon WHO grade IV tumor, which in the vast majority of cases occurs in young children less than two years of age. It most frequently presents as a posterior fossa mass. AT/RT often resembles medulloblastoma by imaging and even H&E microscopy, ...
Article
Auditory brainstem response tracing (mnemonic)
This mnemonic helps when remembering the ascending order of structures that correspond to each waveform in an auditory brainstem response (ABR) tracing:
E COLI
Mnemonic
E: eighth nerve action potential (wave I)
C: cochlear nucleus (wave II)
O: olivary complex (superior) (wave III)
L: later...
Article
Autoimmune encephalitis
Autoimmune encephalitis, also known as autoimmune limbic encephalitis, is an antibody-mediated brain inflammatory process, typically involving the limbic system, although all parts of the brain can be involved.
Autoimmune encephalitis can be divided broadly into two groups, based on whether or...
Article
Autoimmune glial fibrillary acid protein (GFAP) astrocytopathy
Autoimmune glial fibrillary acid protein (GFAP) astrocytopathy, or simply GFAP astrocytopathy, is a rare inflammatory central nervous system (CNS) disorder.
Epidemiology
Given the rarity of the condition, epidemiological data pertaining to autoimmune GFAP astrocytopathy are not well establishe...
Article
Autophony
Autophony, also known as tympanophony, is the experience of finding that one's own voice sounds much louder than normal or is unpleasantly garbled.
Autophony has been described in several clinical entities including superior semicircular canal dehiscence syndrome and patulous Eustachian tube d...
Article
Autosomal recessive spastic ataxia of Charlevoix-Saguenay
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a rare autosomal recessive spastic ataxia unique to the region of Charlevoix-Saguenay, in the Province of Quebec, Canada. It is due to a mutation on the SACS gene locus q12 of chromosome 13. It has been reported in other regio...
Article
AVAglio criteria for glioblastoma
The AVAglio criteria were developed to assess response to first-line treatment of glioblastoma, treated with radiotherapy and temozolomide with or without bevacizumab 1-2. These were adapted from the older Macdonald criteria, but have since been superseded by they RANO criteria (2010) 1.
The A...
Article
Axial plane for imaging of the brain
A consistent axial plane for imaging of the brain needs to be chosen to allow for reproducible image acquisition and comparison. Unlike the sagittal plane, which is intrinsically defined by our inherent left-right plane of symmetry, axial and coronal planes need to be agreed upon and over the ye...
Article
Azygos anterior cerebral artery
An azygos anterior cerebral artery is an uncommon to rare variant of the circle of Willis where the two A1 segments of the anterior cerebral artery (ACA) join to form a single trunk. As a result, there is no anterior communicating artery. This organization is similar to that seen in lower primat...
Article
Babinski-Nageotte syndrome
Babinski-Nageotte syndrome is thought to be a brainstem stroke syndrome in between that of the hemimedullary syndrome (Reinhold syndrome) and the lateral medullary syndrome (Wallenberg syndrome) 1,2.
Terminology
In many texts this eponymous syndrome is incorrectly used synonymously with hemim...
Article
Bálint syndrome
Bálint syndrome is characterized by:
simultanagnosia (inability to perceive more than one object at a time)
optic ataxia
oculomotor apraxia
Pathology
It typically results from damage to the parieto-occipital regions, and has been associated with 1-3:
corticobasal degeneration
posterior co...
Article
Baló concentric sclerosis
Baló concentric sclerosis is a rare and severe monophasic demyelinating disease, considered a subtype of multiple sclerosis, appearing as a rounded lesion with alternating layers of high and low signal intensity on MRI, giving it a characteristic 'bullseye' or 'onion bulb' appearance 1,9.
Epide...
Article
Band heterotopia
Band heterotopia, also known as double cortex syndrome, is a form of diffuse grey matter heterotopia affecting almost only women. Refractory epilepsy is present in nearly all affected patients, with partial complex and atypical absence epilepsy being the most common syndromes.
On imaging, this ...
Article
Band of Giacomini
The band of Giacomini, also known as the tail of the dentate gyrus or limbus Giacomini, is the anteromedial continuation of the dentate gyrus, which in turn is part of the hippocampal formation, along with the hippocampus, subicular complex and entorhinal cortex. It is an important anatomical la...