Neurosonography of the Neonatal Brain Abnormalities Holdorf

Congenital Brain Malformations Disorders of Organogenesis Disorders of Neural Tube Closure Disorders of Diverticulation and Cleavage Disorders of Sulcation/Cellular Migration Destructive Lesions Hydrocephalus Infection – Congenital/Acquired Intracranial masses – Brain Tumors/Cystic Lesions

Disorders of Organogenesis Four stages of organogenesis Neural tube formation - occurs 3-4 weeks gestation Segmentation and diverticulation – occurs 5-6 weeks gestation; forebrain divides; formation of olfactory bulbs, optic vessels and face development Neuronal Proliferation and Migration – occurs 8-24 weeks gestation; cells proliferate and migrate and organize into functional structures Myelination – occurs from 2nd trimester

Chiari Malformations Chiari I – downward displacement of cerebellar tonsils, without displacement of 4th ventricle or medulla ; most common Chiari II – Of greatest clinical importance due to myelomeningocele; displacement of medulla and brainstem Chiari III – the medulla, 4th vent and cerebellum are encased by a high encephalomeningocele

Chiari I

Chiari II Sonographic findings Batwing appearance – Anterior and inferior pointing frontal horns Enlarged lateral ventricles, occipital horns larger than frontal horns (colpocephaly) Slightly enlarged 3rd ventricle displacement of pons, medulla and vermis Non-visualized 4th vent due to compression CSP is completely or partially absent CC usually absent May be hydrocephalus Obliterated Cisterna Magna

Chiari II

Chiari II

Chiari II Diagnosed usually in utero with sonography MS-AFP 4

Chiari III Cerebellum, 4th vent and medulla are contained within a cervical encephelomeningocele 5

Agenesis of Corpus Callosum CC neural fibers that connect the two hemispheres of the cerebrum Allows for communication Development of CC occurs 8-20 weeks gestation Usually associated with other anomalies

Agenesis of CC Sonographic Appearance Widely spaced ventricles Narrow frontal horns Absence of SP Dilated and elevated third vent Sulci are arranged radially – “sunburst sign” Colpocephaly

Agenesis of Corpus Callosum

Agenesis of Corpus Callosum

Agenesis of Corpus Callosum

Lipoma of Corpus Callosum May result from mal-development of neural crest tissues Found in the interhemispheric fissure Can be associated with agenesis of corpus callosum

Lipoma of Corpus Callosum

Dandy Walker Malformation Dilated 4th ventricle that communicates with posterior fossa Theories for its formation include Agenesis of Foramen of Luschka and Magendie Malformation of roof of 4th ventricle Delayed opening of Foramen Magendie 70% associated with other CNS anomalies Can also have chromosomal abnormalities and gastrointestinal, cardiac, MSK, etc., abnormalities

Dandy Walker Malformation Sonographic findings Enlarged 4th ventricle that connects with the cisterna magna Large posterior fossa Hypoplastic cerebellar vermis Hypoplastic cerebellar hemispheres displaced laterally by fourth vent May also have absent CC May have hydrocephalus

Dandy Walker Malformation Images of Dandy Walker Malformation

Disorders of Diverticulation and Cleavage Holoprosencephaly – results from a failure of the prosencephalon to divide into the telencephalon and diencephalon between 4-8 weeks gestation 3 types Alobar Semi Lobar Lobar

Holoprosencephaly Alobar Most severe Characterized by cyclopia and/or hypotelorism with a proboscis above eyes Single crescent shaped vent Thin, fused cerebral cortex usually found in anterior portion of head No falx, no interhemispheric fissure, no corpus callosum Absent 3rd ventricle Fused echogenic Choroid plexus Fused thalami Images

Holoprosencephaly Semi Lobar Single ventricle More brain matter present May see a small portion of falx and interhemispheric fissure in occipital lobe Thalami partially separated May have corpus callosum Less severe facial abnormalities Images

Holoprosencephaly Lobar Least severe Almost complete separation of hemispheres Falx and interhemispheric fissure are present but may be shallow anteriorly Frontal lobes of cerebrum may be fused Absent SP Anterior horns of lateral ventricles are fused and square shaped by occipital horns are separate Third ventricle is usually present Separated thalami Mild facial abnormalities Images

Disorders of Sulcation and Migration Schizencephaly Lissencephaly

Schizencephaly Believed to be caused by neuronal migration malformation Rare Characterized by clefts within the cerebral hemispheres May be unilateral or bilateral May be closed or open

Schizencephaly Open Lip – cleft through cortex and communicates with ventricle

Schizencephaly Open Lip Cleft extends from ventricle to cortical surface of brain

Schizencephaly Closed Lip Gray matter extending from pia mater to ventricle

Lissencephaly Abnormal migration of neurons Lack of sulci Brain appears smooth

Cystic Encephamalacia Destructive Lesions Porencephalic Cyst Hydranencephaly Cystic Encephamalacia

Porencephalic Cyst Area within brain parenchyma filled with CSF Results from brain destruction due to injury, illness, infection, stroke, gene mutations Images - http://www.ultrasoundcases.info/Slide- View.aspx?cat=506&case=2161

Hydranencephaly Thought to be caused by bilateral occlusion of internal carotid arteries May also result from other destructive processes Involves almost complete destruction of cerebral cortex Severest form of porencephaly

Hydranencephaly

Hydranencephaly

Cystic Encephalomalacia Area of focal brain damage due to insult Lesion typically does not communicate with ventricular system Can be caused by infection, thrombus, hypotension, etc. Appears as cystic areas with glial septations

Cystic Encephamalacia Sonographic Appearance Cystic areas containing CSF replace areas of cerebral hemispheres Echogenic septations between cystic cavities

Hydrocephalus Abnormal accumulation of cerebrospinal fluid Caused by one of the following Obstruction to flow (IVOH or EVOH) Decreased absorption Increased production

Hydrocephalus CSF protects brain and spinal cord Regulates chemical environment surrounding the brain Supplies nutrients to nervous system tissue Removes waste from from cerebral metabolism

Hydrocephalus Can be detected in utero by 15 weeks gestation Detected with measurement of lateral ventricle Atrium of lateral vent and glomus > 10mm Evaluate the rest of CNS for abnormalities

Hydrocephalus Intraventricular obstruction – flow obstructed within the ventricular system Post hemorrhagic at Aqueduct or fourth ventricle Posterior fossa subdural hematoma Dandy Walker Malformation Chiari II Malformation Tumor or cyst

Hydrocephalus Extraventricular Obstruction – flow obstructed outside the ventricle Posthemorrhagic scarring Postinfectious scarring Venous obstruction Absence or hypoplasia of arachnoid granulations

Hydrocephalus

Hydrocephalus

Hypoxic-Ishemic Events Germinal Matrix Hemorrhage Posterior Fossa Hemorrhage Subarachnoid Hemorrhage Periventricular Leukomalacia

Germinal Matrix Hemorrhage Germinal Matrix – network of tiny blood vessels and primitive neural tissue located in the subependymal layer of the ventricular system At birth small amount located at caudothalmic groove Highly susceptible to pressure changes Most bleeds occur between within first 7 days Often occur after 1st day of life

Subependymal Hemorrhage Grade I Echogenic, homogeneous mass near caudothalmic groove May appear as prominence in choroid plexus Will become sonolucent with age May completely resolve or result in subependymal cyst

Subependymal Hemorrhage

Intraventricular Hemorrhage Grade II Subependymal hemorrhage extends into the lateral ventricle without ventricular dilation Hyperechoic clot can be seen in a portion of ventricle Choroid plexus may appear asymmetric Clot/choroid may be indistinguishable As clot ages will become sonolucent http://www.ultrasoundcases.info/Slide- View.aspx?cat=501&case=4131

Intraventricular Hemorrhage with Hydrocephalus Grade III Clot extending into ventricle with hydrocephalus The clot and choroid may become more defined Variable degrees of hydrocephalus

Grade III

Posterior Fossa Hemorrhage Can occur due to 4th ventricle germinal matrix Traumatic delivery Coagulopathy ECMO Therapy Mastoid fontanelle or MR evaluation for diagnosis

Intraparenchymal Hemorrhage Grade IV Extension of bleed into brain parenchyma Usually in cerebral cortex] Usually in frontal or parietal lobe Acutely appears as echogenic, homogeneous area with cortex Porencephaly will later develop Images

Subarachnoid Hemorrhage Sonographically can appear as Enlarged interhemispheric fissure Enlarged sylvan fissure Thickened sulci Increased echogenicity

Periventricular Leukomalacia Infarction and necrosis of periventricular white matter Usually occurs adjacent to the external angles of the lateral ventricles Usually bilateral and are often symmetrical Can be diffuse or focal

Periventricular Leukomalacia Initial sonogram may be normal Within 2 weeks, periventricular white matter increases in echogenicity 2-4 weeks, cystic changes develop; ventricles enlarge Cysts can be single or multiple Cystic areas may enlarge or resolve Images - http://emedicine.medscape.com/article/975728-workup

Congenital Infection TORCH Toxoplasma gondii Other (i.e. syphilis) Rubella Cytomegalovirus Herpes simplex virus

Congenital Infection CMV is most common (1% of all births) Can be acquired at birth or after birth with little or no consequence Prenatal CMV infections can cause serious damage Toxoplasmosis caused by toxoplasma gondii is second most common The earlier the infection, usually the worse the associated abnormalities

Congenital Infection Early infection can result in Microcephaly Lissencephaly Hypoplastic cerebellum Polymicrogyria Ventriculomegaly

Congenital Infection Infection can result in Death Congenital malformations Developmental delays Mental deficiencies Seizures

Congenital Infection Sonographic Appearance of CMV and Toxoplasma gondii Periventricular (CMV) or scattered cerebral calcifications (TP) Echogenic foci with or without shadowing Ventriculomegaly and/or intraventricular septations Periventricular cysts Echogenic vasculature

Congenital Infection Herpes (HSV-2) can be acquired transplacentally or vaginal exposure Cystic encephalomalacia of peri-ventricular white matter Scattered calcifications Rubella – extremely rare

Neonatal Acquired Infections Meningitis – clinical diagnosis; imaging used to evaluate complications Subdural fluid collections Edema Ventriculitis – complication of meningitis Hydrocephalus Echogenic debris within ventricle Intraventricular septa formation

Intracranial Masses Only 11% of children with brain neoplasms present before 2 years old Tumors that present prior to that are usually congenital Can be difficult to detect Teratomas – most frequent neoplasms reported in the first year of life Astrocytomas Rhabdoid tumor Ependymomas

Intracranial Masses Ultrasound appearance Usually evaluated with MRI Variable Nonspecific Many are hyperechoic Usually evaluated with MRI

Cystic Intracranial Lesions Common US is best method to evaluate these lesions Arachnoid cysts – most common true cyst of the brain; CSF collects between a split arachnoid Choroid Plexus cysts – usually single and not associated with other CNS abnormalities Subependymal cysts - beneath ependymal lining of vents Frontal Horn cyst – attached directly to frontal horn of lateral vent Galenic Venous malformation - dilation of the Vein of Galen due of vascular malformation

Choroid Plexus Cyst

Subependymal Cysts

Frontal Horn Cyst

Vein of Galen Malformation

Vein of Galen Malformation

References Image slide 5 Chiari 1 retrieved from http://www.mayfieldclinic.com/PE-Chiari.htm#.UoPIzKXIblI on November 13, 2013 Image slide 7 Chiari II retrieved from http://upload.wikimedia.org/wikipedia/commons/d/dc/Chiari2.jpg Image slide 8 Chiari II retrieved from http://www.fetalultrasound.com/online/text/5-022.HTM on November 12, 2013 Image slide 9 Chiari II retrieved from http://embryology.med.unsw.edu.au/embryology/images/8/85/Chiari_II_malformation_MRI02.jpg on November 12, 2013 Image slide 11 Chiari III Encephalocele retrieved from http://rad.usuhs.edu/medpix/cow_image.html?pt_id=12310&imid=45053&quiz=&week=#top on November 12, 2013 Image slide 13 Agenesis of CC retrieved from http://sonoworld.com/fetus/page.aspx?id=107 on November 13, 2013 Image slide 14 from retrieved from http://www.fetalultrasound.com/online/text/5-077.HTM on November 13, 2013 Image slide 15 – Agenesis of CC retrieved from http://www.pear.co.nz/asum/doc.php?d=273&t=-1&tab=2&imageID=1879 November 13, 2013 Image Slide 17 - Corpus Callosum Lipoma retrieved fromhttp://www.adhb.govt.nz/newborn/TeachingResources/Radiology/HUSS/Images/TumourAndAgenesisOfTheCorpusCallosum/ACC%20Lipoma%20coronal%20 1.jpg on November 13, 2013 Image slide 20 – Dandy Walker Malformation retrieved from http://www.ultrasoundcases.info/Case-List.aspx?cat=500 on November 13, 2013 Image Slide 27 – Schizencephaly retrieved from http://www.jultrasoundmed.org/content/28/10/1379/F4.expansion on November 13, 2013 Image slide 28 – Schizencephaly retrieved from http://emedicine.medscape.com/article/413051-overview#a22 on November 13, 2013 Image slide 29 – Schizencephaly retrieved from http://emedicine.medscape.com/article/413051-overview#a22 on November 13, 2013

References Image slide 30 – Lissencephaly retrieved from http://www.glowm.com/ultrasoundAtlas#us561 on November 13, 2013 Image slide 34 Hydranencephaly retrieved from http://radiopaedia.org/images/1479999 on November 13, 2013 Image slide 35 – Hydranencephaly retrieved from http://radiopaedia.org/images/151704 on November 13, 2013 Image slide 37 Cystic Encephelamalacia retrieved from http://www.mdconsult.com/books/figure.do?figure=true&eid=4-u1.0-B978-0-323-05397-6..00047-X-- f9700&sectionEid=4-u1.0-B978-0-32 on November 13, 2013 Image slide 43 Hydrocephalus retrieved from http://www.adhb.govt.nz/newborn/teachingresources/radiology/huss/neonatalotherhuss.htm on November 13, 2013 Image slide 44 Hydrocephalus retrieved from http://www.adhb.govt.nz/newborn/teachingresources/radiology/huss/neonatalotherhuss.htm on November 13, 2013 Image Slide 48 Grade 1 hemorrhage retrieved from http://www.radiologyassistant.nl/en/p440c93be7456fon November 13, 2013 Images slide 51 Grade 3 http://radiopaedia.org/articles/germinal-matrix-haemorrhage on November 13, 2013 Image slide 51 Grade 3 http://radiopaedia.org/articles/germinal-matrix-haemorrhage on November 13, 2013 mage slide 67 choroid Plexus Cyst -retrieved from http://radiopaedia.org/cases/choroid-plexus-cyst-on-ultrasound on November 13, 2013 Image slide 68 Subependymal cyst - http://www.ultrasound-images.com/pediatric.htm on November 13, 2013 Image slide 69 – Frontal Horn Cyst retrieved from http://www.adhb.govt.nz/newborn/teachingresources/radiology/huss/Images/FrontalCyst/FrontalCystCoronal.jpg on November 13, 2013 Image Slide 70 – Vein of Galen Malformation – retrieved from http://lifewiththemyhres.blogspot.com/2011/09/vein-of-galen-malformation-is-special.html on November 13, 2013 Image slide 71 Vein of Galen Malformation retrieved from http://www.adhb.govt.nz/newborn/teachingresources/radiology/huss/Images/VeinOfGalen/VOG%20Coronal%20colour%201.jpg on November 13, 2013