Pediatric Neuroradiology

2ND

RADIOLOGY Subject PEDIATRIC NEURO RADIOLOGY Topic DR. BANDONG Lecturer SHIFTING/ SEPT 25,2008 Shifting /Date COFFEE LOVERS Trans group

PEDIATRIC NEURORADIOLOGY

STAGE 1: DORSAL INDUCTION

– Formation and closure of the Neural

Tube • •

3-4 weeks THREE PHASES: a) Neurulation b) Canalization c) Retrogressive differentiation ANENCEPHALY Failure of brain and skull development Most severe anomaly UTZ diagnosis as early as 20 weeks Polyhydramnios, high alpha-fetoprotein Death

CHIARI II Myelomeningocele Low tentorium Medully kink Hydrocepahalus Beaked tectum Corpus callosum agenesis Polymicrogyria Syringomyelia Lacunar skull -

CEPHALOCELE Defect in the dura and cranium with associated extracranial herniation felt to be related to abnormal closure of the neural tube TWO TYPES: a) Meningocele – herniation of meninges with CSF b) Encephalocele – herniation of brain and meninges Usually midline Occipital location = US Frontal ethmoidal = Asia Often the herniated brain is dysgenic and nonfunctional

CHIARI I Low tonsils Small fourth ventricle Hydromyelia Klippel-Feil Occipitilization of the atlas syrinx -

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CHIARI III Cervical occipital encephalocele that contains cerebellum

MARY YVETTE ALLAIN TINA RALPH SHERYL BART HEINRICH PIPOY KC JAM CECILLE DENESSE VINCE HOOPS CES XTIAN LAINEY RIZ KIX EZRA GOLDIE BUFF MONA AM MAAN ADI KC PENG KARLA ALPHE AARON KYTH ANNE EISA KRING CANDY ISAY MARCO JOSHUA FARS RAIN JASSIE MIKA SHAR ERIKA MACKY VIKI JOAN PREI KATE BAM AMS HANNAH MEMAY PAU RACHE ESTHER JOEL GLENN TONI

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c)

LOBAR  Fusion of only anterior inferior frontal lobes so no faux in that location  Otherwise the brain appears to be quite normal except for lack of septum pellucidum

d) SEPTAL OPTIC DYSPLASIA  Most mild form in w/c ther is no septum pellucidum and the optic nerves are very atrophic.  Schizencephaly may be present in 50% of these cases  Corpus Callosum agenesis may also be seen in this entity

SPINAL DYSRAPHISM

STAGE 2: VENTRAL INDUCTION - Formation of the Brain segments and Face • 5-10 weeks • Three vesicles (prsencephalon, mesencephalon, & rhombencephalon) form the cerebrum, midbrain, cerebellum, and lower brainstem • Division into two hemispheres HOLOPROSENCEPHALIES Failure to separate into hemispheres TYPES: a) ALOBAR  Complete failure  No falx  Single monoventricle  Fused thalami b) SEMI LOBAR  Partial separation of the posterior occipital and temporal lobes  Frontal brain is fused  Thalami partially fused  Ace of spades configuration of the ventricles

•

The optic tracts are thinned bilaterally

The absent septum pellucidum on this coronal T2 image results in a boxlike configuration of the anterior horn of the lateral ventricles. Also note the thin optic tracts.

Coronal T1 demonstrates callosum

image corpus

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CORPUS CALLOSUM AGENESIS • Growth anterior to posterior starting at the genu. Myelination from posterior to anterior • Association with Chiari II, Dandy Walker, Holoprosencephaly and lipomas. • Splaying of the anterior horns (Bulls horn appearance) due to realignment of the Probst bundles. • High third ventricle

DANY WALKER • Defective development of the roof of the fourth ventricle. • Posterior fossa cyst; hydrocephalus often. • Large posterior fossa; high torcula; absent falx in the posterior fossa • Partial Dandy Walker lacks high torcula. Represents a form of cerebellar hypoplasia • Mildest aspect of this spectrum would be mega cisterna magna. • DDX: arachnoid cyst, mega cisterna magna

Dandy Walker Variant • Open communication of the posteroinferior 4th ventricle and posterior CSF density cyst. • Large CSF density cyst occupies much of the posterior fossa which is not enlarged • Hypoplastic cerebellar hemispheres are “winged” anterolaterally by the cyst which stops at the lateral angle of the cerebellar hemispheres and does not extend anterior to them (demonstrate a hypoplastic vermis which is anteriorly and superiorly located). FACIAL ANOMALIES

STAGE 3: HISTOGENESIS

MIGRATION

AND

•

Neuronal migration from germinal matrix to the cortex • Cortical organization • Months: 2-5 • Disorders: o Heterotopias, agyria-pachygyria, polymicrogyria, vascular malformations, teratomas, phakomatosis GRAY MATTER HETEROTOPIAS • Interruption of normal migration of neural blast from the general matrix to the cortex • Various degrees range from simple nodular gray matter heterotopias to band heterotopias to schizencephaly to lissencephaly and to polymicrogyria. • Seizures, mental retardation • Association with corpus callosum agenesis, Chiari malformations, Tuberous Sclerosis, septooptic dysplasia. SCHIZENCEPHALY • Gray matter extension from the ventricle to the cortex. • Two types: closed lip (mild, no CSF within) and open lip (contains CSF, severe with cortical defects and large ventricles). • Association with septo-optic dysplasia and optic atrophy.

LISSENCEPHALY (AGYRIA-PACHYGYRIA) • Most severe form of neuronal migrational anomalies. Patients often have small brains, mental retardation, spasticity, seizures. • Agyria (complete lissencephaly) presents with smooth brain and is identified by figure eight configuration with clefts extending to the sylvian fissure. • Pachygyria (incomplete lissencephaly) has broad, shallow gyre. More mild form the agyria. Type I Lissencephaly • Lack of gyri and alternating layers of grey and white matter. • With a thin outer cortical layer and • A thicker deep layer of neurons

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•

Sylvian fissures shallow

are

vertically

oriented

and

months Anterior portion of the posterior limb of the internal capsule Posterior portion of the posterior limb of the internal capsule Anterior limb of internal capsule Genu of the corpus callosum Splenium corpus callosum Central occipital white matter Peripheral occipital white matter Central frontal white matter Peripheral frontal white matter Centrum semiovale

2-3 months

4-7 months

4-6 months

Birth-2 months

2-3 months 4-6 months 3-4 months 3-5 months 4-7 months 3-6 months 7-11 months 2-6 months

7-11 months 5-8 months 4-6 months 9-14 months 11-15 months 11-16 months 14-18 months 7-11 months

NEUROFIBROMATOSIS 1 (von Recklinghausen) 1:4000 births Chromosome 17 Optic nerve gliomas Hamartomas, gliosis Bone dysplasias Vascular dysplasias Neurofibromas Café-au-lait spots

Pachygyria development of abnormal broad and flat gyri with abnormal shallow sulci

STAGE 4: MYELINATION • • • •

Inferior to superior; posterior to anterior 5-15 months; matures by 3 years Failure: developmental delay, dysmyelinating disease Myelination Milestones o Brain stem, cerebellum, posterior limb of internal capsule: term birth o Anterior limb internal capsule: two months o Splenium of the corpus callosum: three months o Genu corpus callosum: six months o Occipital white matter  Central: five months (T1)/fourteen months (T2)  Peripheral: seven months (T1)/fifteen months (T2) o Frontal white matter  Central: six months (T1)/sixteen months (T2)  Peripheral: eleven months (T1)/eighteen months (T2) Anatomic Region

T1 Weighted Image

Middle cerebellar peduncle

Birth

Cerebral white matter

Birth – 4

T2 Weighted Image Birth – 2 months 3 - 5 months

NEUROFIBROMATOSIS 2 Bilateral acoustic schwannomas Meningiomas Ependymomas Chromosome 22 1:40,000 births NF2 has less skin manifestations than NF1

TUBEROUS SCLEROSIS (BOURNEVILLE’S DISEASE) Chromosome 9 Seizures, mental retardation, adenoma sebaceum Ash leaf spots Cortical tubers, periependymal nodules (hamartomas)

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-

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Giant cell astrocytoma Gray matter heterotopias Angiomyolipomas of the kidneys Rhabdomyoma of the heart Adenoma of the liver Skeletal cysts Lymphangiomyomatosis of the lungs The most common imaging findings are tubers, which are hamartomas along the subependymal surface and cortex. These lesions tend to calcify.

VON HIPPEL LINDAU Hemangioblastomas of the brain and spine Retinal angiomas and hemangioblastomas (? Retinal hemorrhages) Renal cell carcinoma Cysts in any visceral organ Pheochromocytoma

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flammeus in the trigeminal nerve distribution (V1 most common), leptomeningeal venous angiomatosis, and additional clinical symptoms The etiology is probably due to faulty development of cortical venous drainage. There is resultant cortical hypoxia with progressive atrophy and dystrophic calcification. Imaging Findings: o Intracranial “tram track” gyriform calcifications in parietal/occipital lobes in the middle layers of the cortex, ipsilateral to the facial angioma, are common. These were characteristic on plain films and are easily identified on CT, but may not be obvious on MRI. o Cortical atrophy o Skull changes include thickened diploic space, and enlargement of the ipsilateral frontal sinus o Enhancement of the angioma,

gyri, enlarged choroid plexus and subependymal and enlarged medullary veins (the latter two are possibly related to collateral venous drainage. It is unclear if the cortical and surface enhancement is related to the angioma alone or in combination with cortical ischemia). Hyperdensity is seen bilaterally in the parietoocipital region in the cortex, suggesting calcification, in a relatively symmetric distribution

Bone windows. This confirms that the hyperdense material in the cortex is calcification.

STURGE-WEBER SYNDROME (ENCEPHALOTRIGEMINAL ANGIOMATOSIS) A sporadically occurring phakomatosis characterized by a “port-wine”vascular nevus

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MULTIPLE SCLEROSIS •

Serpiginous calcifications are seen overlying the involved segment of the parenchyma.

DYSMYELINATING DISEASES -

Alexander’s disease Adrenoleukodystrophy Metachromatic leukodystrophy Canavan’s disease Krabbe’s disease

ADRENOLEUKODYSTROPHY Metabolic encephalopathy of childhood with widespread demyelination of white matter with inflammatory reaction and atrophy of the adrenal cortex The classical form presents with onset between 5 and 10 years of age A sex-linked recessive inheritance pattern Clinical presentation is typically a young boy previously in good health with behavior problems and compromise of vision, hearing, and intellectual function. Visual and hearing impairment are characteristic features with frequent involvement of white matter adjacent to the medial and lateral geniculate bodies and auditory and visual pathways. Radiologic features include: o White matter involvement in the parietooccipitotemporal regions o Peripheral rim enhancement along the advancing anterior edge of the disease. The enhancement correlates with the active phase of the disease. o Calcifications are infrequently identified on CT scans o Mass effect is not noted, but atrophy is a typical finding as the disease progresses o Atypical patterns of white matter involvement have been described with predilection for the frontal region or asymmetrical involvement of the hemispheres • characterized by central white matter T2 abnormally posteriorly

• • • • • • • • •

possible due to autoimmune-mediated demyelination it is the most common demylenating disease a female preponderance (20 and 40 years) typical location is the callo-septal interface the most typical course is a prolonged relapsingremitting disease. Later, the disease often shifts into a chronicprogressive phase Iso- to hypointense on T1-weighted scans and hyperintense compared to brain on T2-weighted scans Presence of 3 or more discrete lesions that are 5mm or greater in size Periventricular extension of these lesions into the deep white matter, the so called “Dawson’s finger” is characteristic Enhancement is variable and transient and is seen during the active demyelinating stage

ALZHEIMER’S DISEASE • • • • • • •

one of the most common causes of dementia in the elderly approximately 50% of the cases Neuropathologic findings for AD include senile plaques, neurofibrillary tangles, and granulovacuolar degeneration Generalized atrophy – most frequent description Atrophic structural changes in the temporal lobe and hippocampus – as characteristic of AD Increase Fe deposition in the cerebral cortex (MR). Decreased flow and metabolic activity in temporoparietal locations – functional imaging studies (PET, SPECT)

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•

Generalized ventricular enlargement and prominence of the sulci

PARKINSON’S DISEASE • •

• • • • •

chronic progressively disabling disease that falls under the heading of akinetic-rigid syndromes a clinical syndrome, Parkinson’s disease is clinically evident by its triad of bradykinesia and hypokinesia, resting tremor and increased tonicity of voluntary musculature and loss of postural reflexes 1 in 100 individuals over the age of 60 Only a slight male predominance No cure for Parkinson’s disease Current treatment include anticholinergic and dopaminergic medications If left untreated, Parksinson’s disease progresses to frank deterioration of all brain functions and total disability. Consequently, these loss of functions may result in early death.

binds reversibly to hemoglobin much more avidly than oxygen (200-250 times more avidly) leading to high levels of carboxyhemoglobin • it also binds to myoglobin with an even greater affinity than to hemoglobin Pathology in the brain • white matter demyelination • edema and necrosis bilaterally in the globus pallidus, caudate nucleus and cerebellum Clinical Findings • may be subtle and suggest merely a viral illness • headaches, confusion, chest pain, nausea & vomiting, drowsiness, memory impairment, agitation • cherry red skin is not often present

NECT shows bilaterally symmetrical low attenuation lesions in the cerebellum, globus pallidus and caudate nuclei

Imaging: • nonspecific atrophy with enlarged lateral ventricles and widened sulci on CT • On MR, decreased width of the parts compacta between the pars reticularis and the red nucleus may be evident

SPECIAL THANKS KE SHARLYN PATIGAS 

Area of decreased width of the low signal intensity in the pars compacta within the substancia nigra

CO POISONING • •

most fatalities result from fires, malfunctioning stoves, exhaust systems, heaters, suicide attempts impairs oxygen delivery and has its most lethal effects on organs requiring high levels of oxygen, i.e. the brain and heart

VICTORIA

RAMOS

PATI

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