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82 Cards in this Set
- Front
- Back
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What is the pial-ependymal seam
What lines the walls of the opening between the ventricle and the subarachnoid |
A cleft extends from the ependymal surface of brain to the pia mater, and the two layers meet in the cleft : the so-called pial-ependymal seam
dysplastic grey matter..this is often polymicrogyria |
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Is schizencephaly associated with polymicrogyria
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yes ( the gyri by the communticating space)
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What is schizencephaly
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Schizencephaly is a rare developmental disorder of brain characterized by abnormal continuity of histologic grey matter tissue extending from the ependyma lining of the cerebral ventricles to the pial surface of the cerebral hemisphere surface
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What is type 1 schizencephaly
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The clefts can be unilateral or bilateral and may be closed (fused lips). In closed-lip (type I), the cleft walls are in apposition, causing obliteration of the CSF space within the cleft.
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What is type 2 schizencephaly
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The clefts can be unilateral or bilateral and may be separated (open lips). In open-lips (type II), the clefts walls are separated. The CSF fills the cleft from the lateral ventricles to the subarachnoid space that surrounds the hemispheres.
In other words, the pia and the subependymal cells do not create the seam and CSF gets in to the subarachnoid space directly from the opening of the ventricle |
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Which type of schizencephaly has open lips and subarachnoid space filling the with CSF
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type 2
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What is an open lip schizencephaly
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when the wall of the cleft are seperated (epenymal cells and pia cells donot form seam)
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Is schizencephaly associated with polymicrogyria
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yes
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What is common among all holoprosencehaly
What are the 3 types of holoprosencephay What is the most severe form of holoprosencephaly |
As with all types of holoprosencephaly, it is a rare congenital brain malformation in which there is failure of complete separation of the two hemispheres and failure of transverse cleavage into diencephalon and telencephalon.
lobar, alobar, semilobar alobar |
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What is schizencephaly
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Characterized by a cleft lined by heterotopic gray matter (polymicrogyria) that extends from the ependyma of the lateral ventricles to the pial surface of the cerebral cortex.
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What are the features of alobar holoprosencephaly
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single midline monoventricle (or holosphere)
lateral and third ventricles are absent absent septum pellucidum agenesis or hypoplasia of the corpus callosum absent interhemispheric fissure and falx cerebri anosmia fused thalami |
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Why does a monoventricle form in holoprosencephaly
What are the 3 portion of the brain in early brain development What is the prosencephalon |
The anterior telencephalon fails to divide into cerebral hemispheres and a monoventricle results
The prosencephalon (forebrain), the mesencephalon (midbrain), and rhombencephalon (hindbrain) are the three primary portions the prosencephalon separates into the diencephalon (prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum) and the telencephalon (cerebrum). |
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Why is there a fused thalamus and anosmia in holoprosencephaly
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The diencephalon fails to divide into separate thalami, and the olfactory bulbs fail to develop.
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What chromosomal abnormality is holoprosencephaly associated with
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13
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What is the characteristics of semilobar holoprosencephaly
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absence of septum pellucidum
monoventricle with partially developed occipital and temporal horns rudimentary falx cerebri : absent anteriorly incompletely formed interhemispheric fissure partial or complete fusion of the thalami absent olfactory tracts and bulbs agenesis or hypoplasia of the corpus callosum |
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How do the fused ventricles appear in holoprosencephaly
What is the order of severity of the holoprosencehalies |
The fused thalami and basal ganglia are seen as bumps at the base of the holoventnicle anteriorly in the midline.
alobar, semilobar, lobar |
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in alobar holoprosencephaly are the cerebral veins normal
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no, the internal cerebral veins, superior and inferior sagittal sinuses, straight sinuses, and vein of Galen are absent.
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How is alobar holoprosencephaly differentiated from massive hydrocephalus and hydranencephaly
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because in massive hydnocephalus the falx and interhemisphenic fissure are present and in hydranencephaly the thalami are not fused.
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How is semilobar holoprosencephaly differentiated from alobar holoprosencephaly
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there is beginning formation of the occipital or temporal horns or both, and there is some development of the interhemisphenic fissure and falx posteriorl
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What are the characteristics of lobar holoprosencephaly
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fusion of the frontal horns of the lateral ventricles
wide communication of this fused segment with the third ventricle fusion of the fornicies absence of septum pellucidum agenesis or hypoplasia of the corpus callosum |
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Can there be posterior aspects of the callosum present without anterior aspects present in holoprosencephally
Are the thalami fused and is there a falx in lobar holoprosencephally |
yes, despite the callosum forming from front to back
yes to both |
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What is the position of the cerebellar tonsil chiari 1 malformatin
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5mm below the foramen magnum
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What must u exclude before diagnosing chiari 1 malformation
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intracerebral hypotension (look for venous dilation)
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Why does intracranial hypotension cause herniation
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A decrease in CSF volume leads to compensatory dilatation of the vascular spaces and consequent herniation
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What are findings of intracranial hypotension
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enhancing dura, pituitary enlargement, venous vessel enlargement
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Besides intracranial hypotension what are 2 other causes of herniation of the tonsil that can be mistaken for chiari 1
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mass or intracranial hypertension
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What is assiciated with chiari 1 and dandy walker malformation
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syrinx
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What is associated with chiari 2 malformation
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myelomenigocele
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What is a characteristic of chiari 2 malformation
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small bony posterior fossa
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What are 5 associated features of chiari 2 malformation
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(1) colpocephaly; (2) beaked tectum; (3) cascade of an inferiorly displaced vermis behind the medulla; (4) elongated, tubelike fourth ventricle; (5) low-lying torcular herophili; (6) cerebellar hemispheres wrapping around the brainstem anteriorly; (7) concave clivus; (8) medullary spur; and (9) medullary kink.
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What causes a large posterior fossa
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dandy walker malformation
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Can dandy walker and chiari 2 both have agenesis of the corpus callusum and syrinx
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yes
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What malformation causes cystic dilatation of the 4th ventricle, abscent or incomplete vermis
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dandy walker
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Does dandy walker have a large posterior fossa, cystic dilation of the 4th ventricle and possible agenesis of the corpus callosum
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yes
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What are features of DWM?
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large posterior fossa
absent or imcomplete vermis cystic dilation of 4th ventricle hydrocephalus ACC ocipital encephaloceles cortical malformation syrinx |
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Can chiari 1 and DWM both have syrinx
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yes
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What malformation has both ocipital encephaloceles and cortical malformations
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DWM
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absent vermis
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DWM
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DWM
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absent vermis
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What causes pontine enlargement and enlargement of the medulla secondary to gliomas
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NF 1
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Does neurofibromatosis type 1 cause optic glioma and cerebellar glioma in addition to brainstem gliomas
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yes
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Can a neurofibromatosis 1 pt get a tectal glioma (oart of the brainstem)
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yes
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What location of NF1 gliomas are common
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brainstem
tectum optic cerebellum |
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Can optic gliomas extend into the optic tracts in the brain parenchyma
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yes, including the nucleus in the brainstem and the pathway to the occiptial lobe
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What is the ddx of a mass of the intraorbital optic nerve
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optic glioma
optic nerve sheath tumor |
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Do optic nerve sheath tumors enhance
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no, but optic gliomas do
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What are the features of NF1 on MR (T1,T1 gad, T2)
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T1 : enlargement, often iso to hypointense compared to the contralateral side
T1 C+ (GAD) : enhancement is variable T2 hyperintense centrally low signal at the periphery representing the dura 5 |
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What are the features of myelin vacuolization
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no mass effect
no enhancement not seen on T1 hyperintense on T2 |
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Where does myelin vacoulizaion occur
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there are frequently areas of high signal seen on the T2 sequences in the pons, cerebellar white matter, internal capsule and around the corpus callosum. The precise cause for these areas of high signal is uncertain but may be related to myelin vacuolization.
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When does myelin vacuolization occur
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NF1
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What is the classic finding of NF2
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bilat acoustic swhwannoma
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What are 3 neurologic findings of NF2
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intracranial schwannoma(s) : mostly vestibular schwannoma(s)
intracranial and spinal meningioma(s) intraspinal-intramedullary ependymoma(s). |
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What are 2 considerations when periventricular calcification is seen
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TS and congenital infections
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Do hamartomas of the globe of the eye occur in TS
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yes
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What is the most common neurologic abnormality in TS
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cortical or subependymal tubers and white matter abnormalities
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What white matter abnormalities occur in TS
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superficial, radial white matter bands and cyst like lesions
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What are 5 neurologic findings in TS
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cortical tubers
subependymal hamartomas subependymal giant cell astrocytoma white matter abnormalities retinal phakomas |
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What are the features of the white matter abnormalities in TS on MR
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hypointense on T1 and hyperintense on T2
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What is the neuroligic finding of sturge weber
What does the term leptomenigeal mean |
The leptomeningeal haemangioma results in a vascular steal affecting the subjacent cortex and white matter producing localised ischaemia
is a term used to refer to the pia mater and arachnoid mater (not including the dura matter) |
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Does sturge weber result in a vascular malformation
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yes
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What causes the ischemia to adjeacent cortex in sturge weber
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venous congestion
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What happens to the affected area of the brain in TS after contrast is given
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cortical enhancement
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What is static encephalopathy and diplegia associated with
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preterm birth and or in utero white matter injury
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What is diplegia
What does the term static encephalopathy refer to |
refers to paralysis affecting symmetrical parts of the body.
Permanent or unchanging brain damage, that is non-progressive |
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What is static encephalopathy associated with 2
What does the term encephalopathy refer to |
fetal alcohol syndrome, cerebral palsy, and many others
global brain disease and therefore static encephalopathy is a misnomer because different parts are affected in different diseases and this can have many causes of pathology |
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Where is the white matter injury classicaly seen in static encephalopathy
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posterior region of the brain?
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What does acute hypoxic ischemic injury look like
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high signal on T2 in dorsal lateral putamina, and ventrolateral thalami
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What are the causes of stroke in children
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sickle cell
moyamoya trauma infection chd lupus venous |
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What are some infections that may cause stroke 2
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meningitis
post varicella |
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What is moyamoya
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is a vasculo-occlusive disease involving the circle of Willis, typically the terminal ICA. This often leads to stenosis
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What is the difference between moya moya disease and syndrome
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the syndrome is associated with other condition
disease is isolated |
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What do the development of collaterals in moya moya look like
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puff of smoke on angiogram
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What other disease are moya moya associated with
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NF1, downs, sickle cell, XRT
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What should be suspected in a child with reccurent TIA, focal neur deficit, sz and headaches
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moya moya
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What does slow flow on flair cause
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increased signal (brighter)
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What is the signal on flair and postgad in moya moya
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hyperintense
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Does the posterior circulation ever get affected in moya moya
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yes, in the late phases
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What vessels are affected in moya moya
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supraclinoid ICA, MCA, ACA, lenticulostriate
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What is MELAS
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mitochondrial encephalopathy with lactic acidosis and stroke like episode
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When should MELAS be consider
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in non vascular territory infarcts
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Besides MELAS what else should be considered in a nonvasculare territory infarct
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venous occlusion
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What are two findings that are associated with MELAS
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hearing loss and developmental delay
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