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Denervation changes in muscles

Denervation changes in muscles can be observed in a number of settings. Radiographic features MRI in the very early stage, muscle signal may be normal earliest change is increased T2 signal (best seen on a fat saturated T2WI such as STIR) chronic changes are marked by muscle atrophy and fat...

Dense vein sign

The dense vein sign refers to hyperattenuating thrombus within a cortical vein or dural venous sinus due to acute venous thrombosis. When located in the superior sagittal sinus, particularly posteriorly, it is sometimes referred to as the delta, triangle or pseudodelta sign. It is really the sa...

Dentate gyrus

The dentate gyrus is located in the mesial temporal lobe and forms part of the hippocampal formation, along with the hippocampus proper and subiculum. The dentate gyrus receives fibers from the entorhinal cortex via the perforant path and projects fibers to the CA3 portion of the hippocampus. ...

Dentate nucleus

The dentate nucleus is the largest and most lateral of the cerebellar nuclei, located medially within each cerebellar hemisphere, just posterolateral to the fourth ventricle 1. It is part of the triangle of Guillain and Mollaret, connected to the contralateral red nucleus via the superior cere...

Dentatorubral–pallidoluysian atrophy

Dentatorubral–pallidoluysian atrophy (DRPLA) is a clinically heterogenous autosomal dominant CAG repeat expansion disorder that is particularly prevalent within the Japanese population. Epidemiology The majority of case reports are in patients of Japanese origin, where disease prevalence is 1...

Denticulate ligaments

The denticulate ligaments are bilateral triangular lateral extensions of pia mater that anchor the spinal cord to the dura mater. They are formed by pia mater of the spinal cord coursing in-between the dorsal and ventral nerve roots bilaterally. They function to provide stability to the spinal ...

Denver criteria for blunt cerebrovascular injury

The Denver criteria are a set of screening criteria for blunt cerebrovascular injury (BCVI) in trauma used to reduce the need for CT angiography and its associated radiation exposure. Screening criteria The screening protocol criteria 1,3 for blunt cerebrovascular injury are divided into sign...

Desmoplastic infantile astrocytoma and ganglioglioma

Desmoplastic infantile astrocytoma and gangliogliomas are a rare intracranial tumor, which despite their aggressive appearances tend to have a good prognosis and are considered WHO grade I tumors. Terminology Previously considered separate entities, desmoplastic infantile astrocytoma and desm...

Developmental venous anomaly

Developmental venous anomaly (DVA), also known as cerebral venous angioma, is a congenital malformation of veins which drain normal brain. They were thought to be rare before cross-sectional imaging but are now recognized as being the most common cerebral vascular malformation, accounting for ~5...

Dialysis disequilibrium syndrome

The dialysis disequilibrium syndrome (DDS) is a situation characterized by development of neurological symptoms caused by rapid removal of urea during hemodialysis. It develops primarily from an osmotic gradient that develops between the brain and the plasma as a result of rapid haemodialysis. I...

Diaphragma sellae

The diaphragma sellae is one of the folds (or reflections) of the dura mater. It covers the sella turcica and forms the roof over the pituitary fossa 1. Gross anatomy The diaphragma sellae consists of two horizontal leaves of dura mater on the sphenoid bone. It extends from the tuberculum sell...

Diastematomyelia

Diastematomyelia, also known as a split cord malformation, refers to a type of spinal dysraphism (spina bifida occulta) when there is a longitudinal split in the spinal cord. Terminology Although traditionally it has been distinguished from diplomyelia (in which the cord is duplicated rather ...

Diencephalon

The diencephalon is connected above and in front with the cerebral hemispheres; behind with the mid-brain. Its upper surface is concealed by the corpus callosum, and is covered by a fold of pia mater, named the tela choroidea of the third ventricle; inferiorly it reaches to the base of the brain...

Differential diagnoses for temporal lobe tumors

Most tumors of the CNS can potentially occur in the temporal lobe, but entities with a predilection for being diagnosed in this location include: pleomorphic xanthoastrocytoma (PXA) ganglioglioma pilocytic astrocytoma dysembryoplastic neuroepithelial tumor (DNET) multinodular and vacuolatin...

Diffuse astrocytoma

Diffuse astrocytomas, also referred to as low-grade infiltrative astrocytomas, are designated as WHO II tumors of the brain. The term diffuse infiltrating means there is no identifiable border between the tumor and normal brain tissue, even though the borders may appear well-marginated on imagin...

Diffuse astrocytoma grading

Diffuse astrocytomas can be graded in according to a number of systems, the most popular being the WHO grading system. In general these grading systems focus on the presence or absence of a number of histological features 3: cellular atypia/anaplasia mitotic activity microvascular proliferat...

Diffuse axonal injury

Diffuse axonal injury (DAI), also known as traumatic axonal injury (TAI), is a severe form of traumatic brain injury due to shearing forces. It is a potentially difficult diagnosis to make on imaging alone, especially on CT as the finding can be subtle, however, it has the potential to result in...

Diffuse axonal injury (grading)

Grading of diffuse axonal injury has been described histologically according to the anatomic distribution of injury, which correlated with outcome 1-3. The classification was first proposed by Adams in 1989 4 and divides diffuse axonal injury (DAI) into three grades: grade I: involves grey-whit...

Diffuse brainstem gliomas

Diffuse brainstem gliomas, also known as diffuse intrinsic brainstem glioma (DIBG), is a term used to describe infiltrating astrocytomas, no longer recognized as a distinct entity in the 2016 update to the WHO classification of CNS tumors. It encompassed a variety of tumors, ranging from WHO gra...

Diffuse cerebellar atrophy

Diffuse atrophy of the cerebellum refers to a progressive and irreversible reduction in cerebellar volume. It is a relatively common finding and found in a wide variety of clinical scenarios. Terminology Diffuse cerebellar atrophy can be difficult to distinguish from global cerebellar hypopla...

Diffuse cutaneous neurofibroma

Diffuse cutaneous neurofibromas are a rare neurofibroma variant, similar to plexiform neurofibromas which may be co-existent. Both neurofibromas and plexiform neurofibromas are discussed separately. Terminology There are variable uses and some confusion about the distinction between plexiform...

Diffuse dural calcification

Diffuse dural calcification can occur in a number of settings. These include parathyroid abnormalities hyperparathyroidism secondary hyperparathyroidism 2 tertiary hyperparathyroidism 3 renal failure 6 nephrogenic systemic fibrosis 1 congenital syndromes basal cell nevus syndrome Differ...

Diffuse glioma

Diffuse glioma is a term used to encompass a variety of tumors of the central nervous system, which histologically appear similar to glial cells, specifically astrocytomas, oligodendrogliomas and oligoastrocytomas, ranging from WHO grade II to grade IV tumors 1. Importantly, it does not include ...

Diffuse leptomeningeal glioneuronal tumor

Diffuse leptomeningeal glioneuronal tumor (also previously known as disseminated oligodendroglial-like leptomeningeal tumor of childhood) is a rare and only recently described tumor of the central nervous system included in the WHO classification of CNS tumors in the 2016 update 2,5. Morphologic...

Diffuse midline glioma H3 K27M–mutant

Diffuse midline glioma H3 K27M–mutant is a specific entity added to the 2016 update of the WHO classification of CNS tumors, that represents the majority of diffuse intrinsic pontine gliomas, although identical tumors are also found elsewhere in the midline (e.g. brainstem, spinal cord and thala...

Diffusion kurtosis imaging

Diffusion kurtosis imaging (DKI) is an advanced neuroimaging modality which is an extension of diffusion tensor imaging by estimating the kurtosis (skewed distribution) of water diffusion based on a probability distribution function. It provides a high order diffusion of water distribution and a...

Diffusion tensor imaging and fiber tractography

Diffusion tensor imaging (DTI) is an MRI technique that uses anisotropic diffusion to estimate the axonal (white matter) organization of the brain. Fiber tractography (FT) is a 3D reconstruction technique to assess neural tracts using data collected by diffusion tensor imaging. Diffusion-weigh...

Diffusion weighted MRI in acute stroke

Diffusion weighted imaging (DWI) is a commonly performed MRI sequence for evaluation of acute ischemic stroke, and is sensitive in the detection of small and early infarcts. Conventional MRI sequences (T1WI, T2WI) may not demonstrate an infarct for 6 hours, and small infarcts may be hard to appr...

Diplomyelia

Diplomyelia is a rare spinal cord malformation in which the cord is duplicated. It should be distinguished from diastematomyelia in which a single cord is split. Having said that it has been proposed that the term be abandoned in favor of split cord malformation, which encompasses both diastemat...

Disappearing basal ganglia sign

The disappearing basal ganglia sign is one of the early signs of a middle cerebral artery (MCA) infarction. It is defined as the loss of delineation of the basal ganglia, due to blurring of their grey-white matter interface and hypoattenuation, consequent to cytotoxic edema at the time of an isc...

Disproportionately enlarged subarachnoid space hydrocephalus (DESH)

Disproportionately enlarged subarachnoid space hydrocephalus (DESH) is a pattern of communicating hydrocephalus characterized by crowding of the sulci superiorly near the vertex accompanied by enlargement of CSF spaces more inferiorly, particularly in the Sylvian fissures 1. It is a prominent fe...

Distal dural ring

The distal dural ring is an anatomical landmark that separates the extradural from the intradural intracranial internal carotid artery (ICA). It is located at the junction of the cavernous, clinoid and ophthalmic segments of the ICA. Gross anatomy Anatomy of this region is complex and varied a...

Divry van Bogaert syndrome

Divry van Bogaert syndrome is a familial juvenile-onset syndrome characterized by livedo racemosa, juvenile ischemic stroke, juvenile cerebral white matter disease leading to premature dementia, and epilepsy. Clinical presentation juvenile ischemic stroke epilepsy early-onset cognitive impai...

Dolichoectasia

The term dolichoectasia means dilated and elongated. It is used to characterize arteries that have shown a significant deterioration of their tunica intima (and occasionally the tunica media), weakening the vessel walls and causing the artery to elongate and distend. Epidemiology Dolichoectasi...

Dopaminergic pathways

Dopaminergic pathways include: mesolimbic mesocortical striatonigral tuberoinfundibular

Dorsal brainstem syndrome

Dorsal brainstem syndrome is a rare subset of hypoxic ischemic encephalopathy in neonates limited to the isolated involvement of the brainstem with sparing of the supratentorial brain. Due to its subtle imaging features it is often undiagnosed. Clinical presentation Injuries involving the tegm...

Dorsal columns

The dorsal columns, or posterior columns, are ascending pathways primarily concerned with sensory function. They are responsible for transmitting vibration, conscious proprioception, and fine (discriminative) touch 1,2. The dorsal columns are divided two tracts, which are discussed separately 2...

Dorsal cord syndrome

Dorsal cord syndrome, also known as posterior spinal cord syndrome, is one of the incomplete cord syndromes resulting from pathology affecting the posterior part of the spinal cord, particularly the dorsal columns and potentially (in larger lesions) the lateral corticospinal tracts 1. Clinical...

Dorsal cyst of holoprosencephaly

The dorsal cyst of holoprosencephaly is a large cerebrospinal fluid cavity present in holoprosencephaly that occupies the area above the dorsocaudal aspect of the diencephalon. This communicates directly with the prosencephalic, telencephalic, or diencephalic ventricle. This cavity usually abuts...

Dorsal dermal sinus

Dorsal dermal sinus is an epithelium-lined tract from the skin to the spinal cord, cauda equina, or arachnoid as in a form of spinal dysraphism. Clinical presentation A dorsal dermal sinus manifests as a small dimple or pinpoint ostium, which is often associated with an area of hyperpigmented...

Dorsal horn

The dorsal horn of the spinal cord is one of the grey longitudinal columns found within the spinal cord. It primarily acts as the termination of primary afferent fibers via the dorsal roots of the spinal nerves. Gross Anatomy On transverse section of the spinal cord the spinal grey matter is d...

Dorsal root ganglion

The dorsal root ganglia are an enlargement of the dorsal root of spinal nerves representing the cell bodies of the primary somatosensory neurons. Gross anatomy Each dorsal root ganglion is oval and proportional in size to its related root. They are usually found just distal to the intervertebr...

Dorsal thoracic arachnoid web

Dorsal thoracic arachnoid web refers to a thickened band of arachnoid over the dorsal aspect of the cord. It usually causes a focal thoracic cord distortion with consequent neurological dysfunction. On imaging, it is characterized by a focal dorsal indentation and anterior displacement of the ...

Double density sign (berry aneurysm)

Double density sign of berry aneurysms refers to the angiographic appearance of a small intracranial aneurysm projecting in front or behind a vessel of similar caliber. As such, the border of the aneurysm cannot easily be seen, but the extra contrast within it can be seen as a rounded area of in...

Double density sign (disambiguation)

The double density sign can refer to several radiological signs: double density sign (left atrial enlargement) double density sign (berry aneurysm) double density sign (osteoid osteoma)

Double density sign (osteoid osteoma)

The double density sign, also sometimes clumsily referred to as the hotter spot within hot area sign, is a bone scan sign of an osteoid osteoma. It refers to a central focus of intense uptake (the nidus) within a surrounding lower, but nonetheless increased uptake, rim. See also double densit...

Double inversion recovery sequence

Double inversion recovery (DIR) is an inversion recovery MRI pulse sequence that uses two different inversion pulses. The technique can be used to suppress signal from two different tissues or to suppress signal that moved between the two pulses. In the first instance, used in neuroimaging, two...

Double panda sign

The double panda sign refers to the combination of the face of the giant panda and face of the miniature panda (cub of the giant panda) seen on T2 weighted images of midbrain and pons respectively in Wilson disease. The midbrain face of the giant panda sign consists of normal intensity of red n...

Double skull sign (cephalohematoma)

The double skull sign is an eggshell calcification seen on CT in early cases of calcified cephalohematomas.

Down syndrome

Down syndrome (or trisomy 21) is the most common trisomy and also the commonest chromosomal disorder. It is a major cause of intellectual disability, and also has numerous multisystem manifestations. Epidemiology According to the World Health Organization (WHO), the approximate worldwide incid...

Dravet syndrome

Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is a rare form of epilepsy usually presenting in the first 1-2 years of life. Clinical presentation The typical presentation occurs during the first six months to one year of life as tonic-clonic seizures in a fe...

Dual rim sign (brain abscess)

The dual or double rim sign is seen on MRI in approximately 75% of cerebral abscesses and is helpful in distinguishing an abscess from a glioblastoma. On both susceptibility weighted imaging (SWI) and T2WI it consists of two concentric rims surrounding the abscess cavity, outer one of which is...

Duane syndrome

Duane syndrome, also known as Duane retraction syndrome, is a rare congenital disease characterized by non-progressive strabismus. It is caused by a variable degree of abnormal development of one or both 6th cranial nerves (CN VI). Epidemiology It presents during childhood and it accounts for ...

Dumbbell appearance of spinal tumors

The dumbbell appearance of spinal tumors refers to a tumor which has both a component within the canal and a component in the paravertebral space contiguous with each other via a thinner tumor component traversing the neural exit foramen. The appearance can be seen in: spinal nerve sheath tumo...

Duplicated middle cerebral artery

The duplicated middle cerebral artery is an anatomical variant in which there are two middle cerebral arteries originating from the distal end of the internal carotid artery. Supply The duplicated artery supplies the anterior temporal lobe. Differential diagnosis It should not be confused wi...

Dural arteriovenous fistula

Dural arteriovenous fistulas (dAVF) are a heterogeneous collection of conditions that share arteriovenous shunts from dural vessels. They present variably with hemorrhage or venous hypertension and can be challenging to treat. Epidemiology Most dural arteriovenous fistulas present in adulthood...

Dural arteriovenous shunts

Dural arteriovenous shunts (DAVS) are rare congenital arteriovenous malformations (CAVMs). On the basis of clinical and anatomical features DAVS have three different types: dural sinus malformations (DSMs) infantile or juvenile DAVS (IDAVS) adult DAVS (ADAVS)

Dural ectasia

Dural ectasia refers to ballooning or widening of the dural sac which can result in posterior vertebral scalloping and is associated with herniation of nerve root sleeves. Clinical presentation Patients with dural ectasia may present with low back pain or radicular pain in the buttocks or legs...

Dural enhancement

Pachymeningeal enhancement, also known as dura-arachnoid enhancement 4, refers to a dural and outer layer of arachnoid pattern of enhancement seen following contrast administration and may occur in the conditions listed below: infection intracranial tumor metastases intracranial hypotension ...

Dural masses

Dural masses can be the result of a number of different tumors and conditions, although meningiomas are by far the most common. The differential of a dural mass includes: meningioma hemangiopericytoma primary dural lymphoma Rosai-Dorfman disease solitary fibrous tumor of the dura primary i...

Dural metastases

Dural or pachymeningeal metastases are a relatively common cause of dural masses, although they are less common than brain metastases and meningiomas. They can occur both within the spine and intracranially - this article is focused on intracranial dural masses. Clinical presentation Patients...

Dural osteoma

Dural osteomas are a cause of focal intracranial calcification (colloquially known as brain stones). They are difficult to differentiate from an ossified "burnt out" meningiomas and ossification of the falx. Some reports are actually contradictory 1,4, suggesting that at least some lesions have ...

Dural sinus malformations

Dural sinus malformations (DSMs) are congenital vascular malformations characterized by massive dilatation of one or more dural venous sinuses. This condition is typically associated with arteriovenous shunts (DAVS). Subtypes There are two types of DSMs DSM involving the confluence of sinuses...

Dural sinus occlusive disease

Dural sinus occlusive disease (DSOD) is an infective form of dural sinus thrombosis (thrombophlebitis) commonly seen in the setting of acute otomastoiditis. It typically presents with: severe headaches high fevers sixth nerve palsy - due to involvement of Dorello's canal altered conscious st...

Dural tail sign

The dural tail sign occurs as a result of thickening and enhancement of the dura and is most often seen adjacent to a meningioma. Initially, the sign was felt to be pathognomonic of meningiomas, however as radiologist's experience grew, it has become increasingly noted to be present in many oth...

Dural tail sign (mnemonic)

A useful mnemonic to remember differential diagnoses associated with a dural tail sign is: My Scary Dog Likes To Stand Guard Mnemonic M: meningioma S: sarcoidosis D: dural metastases L: lymphoma T: tuberculoma S: schwannoma G: glioma

Dural venous sinuses

Dural venous sinuses are venous channels located intracranially between the two layers of the dura mater (endosteal layer and meningeal layer). They can be conceptualised as trapped epidural veins. Unlike other veins in the body, they run alone, not parallel to arteries. Furthermore, they are va...

Dural venous sinus thrombosis

Dural venous sinus thrombosis is a subset of cerebral venous thrombosis, often coexisting with cortical or deep vein thrombosis, and presenting in similar fashions, depending mainly on which sinus is involved. As such, please refer to the cerebral venous thrombosis article for a general discuss...

Dura mater

The dura mater, also known as the pachymeninx (plural: pachymeninges), is the tough outer layer of the meninges that surrounds the central nervous system and is pierced by the cranial nerves, the internal carotid arteries and the vertebral arteries. Intracranially, it is formed by two layers: ...

Duret hemorrhage

Duret hemorrhage is a small hemorrhage (or multiple hemorrhages) seen in the medulla or pons of patients who are rapidly herniating. Pathology Raised supratentorial pressure causes the brainstem and mesial temporal lobes to be forced downwards through the tentorial hiatus. As a result of this...

Dyke-Davidoff-Masson syndrome

Dyke-Davidoff-Masson syndrome (DDMS) is a condition characterized by hemicerebral atrophy/hypoplasia secondary to brain insult usually in fetal or early childhood period and is accompanied by ipsilateral compensatory osseous hypertrophy and contralateral hemiparesis. It is characterized by: th...

Dynamic contrast enhanced (DCE) MR perfusion

Dynamic contrast-enhanced (DCE) MR perfusion, sometimes also referred to as permeability MRI, is one of the main MRI perfusion techniques which calculates perfusion parameters by evaluating T1 shortening induced by a gadolinium-based contrast bolus passing through tissue. The most commonly calcu...

Dynamic susceptibility contrast (DSC) MR perfusion

Dynamic susceptibility contrast (DSC) MR perfusion is one of the most frequently used techniques for MRI perfusion, and relies on the susceptibility induced signal loss on T2* weighted sequences which results from a bolus of gadolinium-based contrast passing through a capillary bed. The most co...

Dysembryoplastic neuroepithelial tumor

Dysembryoplastic neuroepithelial tumors (DNET) are benign (WHO Grade I) slow growing glioneuronal tumors arising from either cortical or deep grey matter. The vast majority are centered in cortical grey matter, arise from secondary germinal layers, and are frequently associated with cortical dys...

Dysgenesis of the corpus callosum

Dysgenesis of the corpus callosum may be complete (agenesis) or partial and represents an in utero developmental anomaly. It can be divided into: primary agenesis: the corpus callosum never forms secondary dysgenesis: the corpus callosum forms normally and is subsequently destroyed Epidemiolo...

Dysgerminoma

A dysgerminoma refers to a class of tumor with germ cell origin. This can refer to: CNS dysgerminoma ovarian dysgerminoma See also germ cell tumors

Dysmyelinating disorders

Dysmyelinating disorders are a subset of white matter disorders characterized by abnormal myelination 1. They include numerous inherited conditions that are characterized by a defective structure and function of the myelin sheath 2. Terminology Dysmyelinating disorders are often thought of be...

Early DWI reversal in ischemic stroke

Early DWI reversal in ischemic stroke (also referred to as diffusion lesion reversal) is encountered early in the course of ischemic infarction, most frequently in the setting of reperfusion within 3 to 6 hours of onset 1. DWI reversal is defined as the interval disappearance of the initially-v...

Ears of the lynx sign (brain)

The ears of the lynx sign refers to abnormal T2/FLAIR cone-shaped hyperintensity at the tip of the frontal horn of the lateral ventricles in the region of forceps minor which resembles the tufts of hair crowning the ears of a lynx. This sign is seen in hereditary spastic paraplegia with thin co...

Eastern equine encephalitis

Eastern equine encephalitis (EEE) is one of many viral encephalitides and results from infection with the eastern equine encephalitis virus. Clinical presentation Most patients have non-specific viral prodromal symptoms for approximately one week, including fevers, headache, nausea and vomitin...

EBV associated smooth muscle tumor

Epstein-Barr virus-associated smooth muscle tumors (EBV-SMT) are rare and encountered in immunocompromised individuals. Epidemiology These tumors are generally exceedingly rare, and only seen with any frequency in the setting of immunosuppression, particularly in HIV/AIDS patients, but also po...

EBV-positive diffuse large B-cell lymphoma, NOS

EBV-positive diffuse large B-cell lymphoma, NOS (not otherwise specified) is one of the immunodeficiency-associated CNS lymphomas, usually seen in elderly individuals. Unlike other EBV-associated CNS lymphomas, these individuals do not have a defined cause for immunosuppression. It is believed t...

Eccentric target sign (cerebral toxoplasmosis)

The eccentric target sign is considered pathognomonic for cerebral toxoplasmosis. It is seen on postcontrast MRI/CT as a ring enhancing lesion with an eccentrically located enhancing mural nodule. It is believed that this mural nodule is an extension from the abscess wall itself with inflamed ve...

Ecchordosis physaliphora

Ecchordosis physaliphora is a congenital benign hamartomatous lesion derived from notochord remnants, usually located in the retroclival prepontine region, but can be found anywhere from the skull base to the sacrum. Terminology There has been some controversy as to whether intradural chordom...

Ectopia lentis

Ectopia lentis refers to subluxation or dislocation of the lens of the eye secondary to dysfunction or disruption of zonular fibers. Pathology Etiology trauma systemic and syndromic disorders Marfan syndrome typically upwards and out most common spontaneous cause 2 homocystinuria - typ...

Ectopic posterior pituitary

An ectopic posterior pituitary reflects a disruption of normal embryogenesis of the posterior pituitary and is one of the more common causes of pituitary dwarfism. Although it can be an isolated abnormality, numerous other congenital central nervous system malformations have been identified. Whe...

Edinburgh criteria for lobar intracerebral hemorrhage associated with cerebral amyloid angiopathy

The Edinburgh criteria were proposed in 2018 in order to diagnose lobar intracerebral hemorrhage associated with cerebral amyloid angiopathy (CAA) 1. They can potentially be used to rule CAA-associated lobar hemorrhage either in or out, but require external validation in other patient population...

Efface

Efface is a term frequently used by radiologists, most often in the context of CSF-containing spaces in the brain (sulci and ventricles). Unfortunately, it is often used incorrectly. The word efface, in general English usage, means to cause something to fade or disappear 1,2. In the context o...

Elevated prolactin (differential)

Elevated prolactin can be due to a number of causes, including elevated production/secretion as well as reduced inhibition. Prolactin is controlled by numerous homeostatic mechanisms, with tonic secretion of prolactin inhibitory hormone (dopamine) by the hypothalamus having a dominant effect 1...

Eloquent cortex

Eloquent cortex is a term that refers to specific brain areas that directly controls function, thus damage to this areas generally produces major focal neurological deficits. Examples of eloquent cortex are: primary motor cortex (precentral gyrus) primary somatosensory cortex (postcentral gyr...

Elster's rule (pituitary gland)

Elster's rule provides a guide to the expected approximate pituitary gland's height in relation to age 1. The rule follows an even-numbered pattern of 6, 8, 10, and 12 1: 6 mm pituitary gland height in infants and children 8 mm pituitary gland height in men and postmenopausal women 10 mm pitu...

Embryonal tumors with multilayered rosettes (ETMR)

Embryonal tumors with multilayered rosettes (ETMR) are rare small round blue cell tumor of the central nervous system and are one of the most aggressive brain tumors usually encountered in children. Terminology Previously embryonal tumors with multilayered rosettes (ETMR) were known as embryo...

Emergency CT head (mnemonic)

A useful mnemonic which is used to read an emergency head CT scan is: Blood Can Be Very Bad Mnemonic Using a systematic approach will help to ensure that significant neuropathology will not be missed. B: blood look for epidural hematoma, subdural hematoma, intraparenchymal hemorrhage, intra...

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