Published on February 23, 2014
DR/Ahmed Bahnassy Consultant radiologist PSMMC
Safe Bedside- compatible Reliable Early imaging Serial imaging: Brain maturation Evolution of lesions Inexpensive Suitable for screening
Exclude/demonstrate cerebral pathology Assess timing of injury Assess neurological prognosis Help make decisions on continuation of neonatal intensive care Optimise treatment and support
Embryology At the end of the 4th week after conception, the cranial end of the neural tube differentiates into 3 primary brain vesicles Prosencephalon (Forebrain) Diencephalon Thalmus Hypothalmus Posterior Pituitary Telencephalon Cerebral hemispheres Cortex & Medullary Center Corpus Striatum Olfactory System Mesencephalon (midbrain) Cerebral Aqueduct Superior and inferior colliculi (quadrigeminal body) Rhombencephalon (hindbrain) Myelencephalon Closed part of medulla oblongata Metencephalon Pons Cerebellum 3rd, 4th, and lateral ventricles Choroid Plexus
Anatomy of the Neonatal Brain Cerebrum 2 Hemispheres (Gray and White Matter) Lobes of the Brain Frontal Parietal Occipital Temporal Gyrus and Sulcus Gyrus: convulutions of the brain surface causing infolding of the cortex Sulcus: Groove or depression separating gyri.
Anatomy of the Neonatal Brain Cerebrum Fissures Interhemispheric Area of Falx Cerebri Sylvian Most lateral aspect of brain Location of middle cerebral artery Quadrigeminal Posterior and inferior from the cavum vergae Vein of Galen posterior to fissure Falx Cerebri Fibrous structure separating the 2 cerebral hemispheres Tentorium Cerebelli “V” shaped echogenic extension of the falx cerebri separating the cerebrum and the cerebellum
Cerebrum Basal Ganglia collection of gray matter Caudate Nucleus & Lentiform Nucleus Largest basal ganglia Relay station between the thalmus and cerebral cortex Germinal Matrix includes periventricular tissue and caudate nucleus Thalmus 2 ovoid brain structures Located on either side of the 3 rd ventricle superior to the brainstem Connects through middle of the 3rd ventricle through massa intermedia Hypothalmus “Floor” of 3rd Ventricle Pituitary Gland is connected to the hypothalmus by the infundibulum
Anatomy of the Neonatal Brain Meninges Dura Mater Arachnoid Pia Mater Cerebral Spinal Fluid (CSF) Surrounds and protects brain and spinal cord. 40% formed by ventricles, 60% extracellular fluid from circulation.
Ventricular System Lateral Ventricles: Largest of the CSF cavities. Frontal Horn Body Occipital Horn Temporal Horn Trigone “Atrium” Foramen of Monro 3rd Ventricle Aqueduct of Sylvius 4th Ventricle Foramen of Luschka Foramen of Megendie Cisterns Cisterna Magna Spaces at the base of the skull where the arachnoid is widely separated from the pia mater.
Anatomy of the Neonatal Brain Cavum Septum Pellucidum Choroid Plexus Corpus Callosum Broad band of connective fibers between cerebral hemispheres. The “roof” of the lateral ventricles. Cavum Septum Pellucidum Thin, triangular space filled with CSF Lies between the anterior horn of the lateral ventricles. “Floor” of the corpus callosum Choroid Plexus Mass of specialized cells that regulate IV pressure by secretion/absorption of CSF Within atrium of the lateral ventricles
Anatomy of the Neonatal Brain Brain Stem Midbrain Pons Medulla Oblongata
Anatomy of the Neonatal Brain Cerebellum Posterior cranial fossa 2 Hemispheres connected by Vermis 3 Pairs of Nerve Tracts Superior Cerebellar Peduncles Middle Cerebellar Peduncles Inferior Cerebellar Peduncles
Cerebrovascular System Internal Cerebral Arteries Vertebral Arteries Circle of Willis Middle Cerebral Artery Longest branch in Circle of Willis that provides 80% of blood to the cerebral hemispheres
Anatomy of the Neonatal Skull Fontanelles (“Soft Spots”) Spaces between bones of the skull
Function and Physiology Cerebellum Controls Skeletal Muscle Movement Cerebral Hemispheres Frontal Voluntary muscles, speech, emotions, personality, morality, and intellect Parietal Pain, temperature, and spatial ability Occipital Vision Temporal Auditory and Olfactory
Indications for Sonographic Exam Cranial abnormality found on pre-natal sonogram Increasing head circumference with or without increasing intracranial pressure Acquired or Congenital inflammatory disease Prematurity Diagnosis of hypoxia, hypertension, hypercapnia, hypernaturemia, acidosis, pneumothorax, asphyxia, apnea, seizures, coagulation defects, patent ductus arteriosus, or elevated blood pressure History of birth trauma or surgery Suctioning of infant Genetic syndromes and malformations
Sonographic Technique What anatomy do you scan? Supratentorial Compartment Both cerebral hemispheres Basal Ganglia Lateral & 3rd Ventricle Interhemispheric fissure Subarachnoid space Views Coronal Modified Coronal (anterior fontanelle) Sagittal (anterior fontanelle) Parasagittal (anterior fontanelle) Infratentorial Compartment Cerebellum Brain Stem 4th Ventricle Basal Cisterns Views Coronal (mastoid fontanelle and occipitotemporal area) Modified Coronal Sagittal Parasagittal (with increased focal depth & decreased frequency)
Transucers : 5–7.5–10 MHz Appropriately sized Standard examination: use 7.5–8 MHz Tiny infant and/or superficial structures: use additional higher frequency (10 MHz) Large infant, thick hair, and/or deep structures: use additional lower frequency (5 MHz)
Anterior Fontanel The Standard view window Temporal Supplementary view window Posterior Fontanel Supplementary view window Mastoid Fontanel Supplementary view window
Coronal Views (at least 6 standard planes)
Sagittal Views (at least 5 standard planes)
1. Interhemispheric fissure 2. Frontal lobe 3. Skull 4. Orbit 5. Frontal horn of lateral ventricle 6. Caudate nucleus 7. Basal ganglia 8. Temporal lobe 9. Sylvian fissure 10. Corpus callosum 11. Cavum septum pellucidum 12. Third ventricle 13. Cingulate sulcus 14. Body of lateral ventricle 15. Choroid plexus (*: plexus in third ventricle) 16. Thalamus 17. Hippocampal fissure 18. Aqueduct of Sylvius 19. Brain stem 20. Parietal lobe 21. Trigone of lateral ventricle 22. Cerebellum (a: hemispheres; b: vermis) 23. Tentorium 24. Mesencephalon 25. Occipital lobe 26. Parieto-occipital fissure 27. Calcarine fissure 28. Pons 29. Medulla oblongata 30. Fourth ventricle 31. Cisterna magna 32. Cisterna quadrigemina 33. Interpeduncular fossa 34. Fornix 35. Internal capsule 36. Occipital horn of lateral ventricle 37. Insula 38. Falx 39. Straight sinus (sinus rectus) 40. Temporal horn of lateral ventricle 41. Circle of Willis 42. Prepontine cistern
Questions to be answered during exam
Doppler uses Typical transcranial Doppler with imaging scan and recording from middle cerebral artery (MCA). Doppler image shows circle of Willis. A = anterior cerebral artery M = middle cerebral artery P = posterior cerebral artery RI = resistive index Demonstrates Decreased blood flow/ischemia/infarction Vascular abnormalities Cerebral Edema Hydrocephalus Intracranial Tumors Near-field structures
Middle Cerebral Artery
Carotid Siphon - Genu
Anterior Cerebral Artery
Posterior Cerebral Artery – P1
BLOOD FLOW VELOCITY • Changes in flow velocity occur when: • There is a change in vessel caliber • There is a change in volume flow
should we do doppler study vein of galen aneurysm cyst=doppler
Chiari Malformation Downward displacement of the cerebellar tonsils and the medulla through the foramen magnum. Arnold-Chiari malformation shows a small displaced cerebellum, absence of the cisterna magna, malposition of the fourth ventricle, absence of the septum pellucidum, and widening of the third ventricle Commonly related to meningomyelocele
Chiari Malformation Sonographic Features Small posterior fossa Small, displaced Cerebellum Possible Myelomeningocele Widened 3rd Ventricle Cerebellum herniated through enlarged foramen magnum 4th ventricle elongated Posterior horns enlarged Cavum Septum pellucidum absent Interhemispheric Fissure widened Tentorium low and hypoplastic
Holoprosencephaly Common large central ventricle because prosencephalon failed to cleave into separate cerebral hemispheres. Alobar Holoprosencephaly (Most Severe) Fused thalami anteriorly to a fused choroid plexus Single midline ventricle No falx cerebrum, corpus callosum, interhemispheric fissure, or 3rd ventricle Semilobar Holoprosencephaly Single ventricle Presents with portions of the falx and interhemispheric fissure Thalmi partially separated 3rd Ventricle is rudimentary Mild facial anomalies Lobar Holoprosencephaly (Least Severe) Near complete separation of hemipsheres; only anterior horns fused Full development of falx and interhemispheric fissure
Holoprosencephaly Alobar Holoprosencephaly Semilobar Holoprosencephaly
Dandy-Walker Malformation Congenital anomaly of the roof of the 4th ventricle with occlusion of the aqueduct of Sylvius and foramina of Magendie and Luschka A huge 4th ventricle cyst occupies the area where the cerebellum usually lies with secondary dilation of the 3rd ventricle; absent cerebellar vermis
Agenesis of the Corpus Callosum Complete or partial absence of the connection tissue between cerebral hemispheres Narrow frontal horns Marked separation of lateral ventricles Widening of occipital horns and 3rd Ventricle “Vampire Wings”
Agenesis of the Corpus Callosum
Ventriculmegaly Enlargement of the ventricles without increased head circumference Communicating Non-communicating Resut of cerebral atrophy Sonographic Findings Ventricles greater than normal size first noted in the trigone and occipital horn areas Visualization of the 3rd and possibly 4th ventricles Choroid plexus appears to “dangle” within the ventricular trium Thinned brain mantle in case of cerebral atrophy
Hydrocephalus Enlargement of ventricles with increased head circumference Communicating Non-communicating Sonographic Findings Blunted lateral angles of enlarged lateral ventricles Possible intrahemispheric fissure rupture Thinned brain mantle Aqueductal Stenosis Most common cause of congenital hydrocephalus Aqueduct of Sylvius is narrowed or is a small channel with blind ends; occasionally caused by extrinsic lesions posterior to the brain stem Sonographic Findings Widening of lateral and 3rd ventricles Normal 4th ventricle
Hydrancephaly Occlusion of internal carotid arteries resulting in necrosis of cerebral hemispheres Absence of both cerebral hemispheres with presence of the falx, thalmus, cerebellum, brain stem, and postions of the occipital and temporal lobes Sonographic findings Fluid filled cranial vault Intact cerebellum and midbrain
Cephalocele Herniation of a portion of the neural tube through a defect in the skull Sonographic Findings Sac/pouch containing brain tissue and/or CSF and meninges Lateral Ventricle Enlargement
Subarachnoid Cysts Cysts lined with arachnoid tissue and containing CSF Causes Entrapment during embryogenesis Residual subdural hematoma Fluid extravasation sectondary to meningeal tear or ventricular rupture
Hemorrhagic Pathology Subependymal-Intraventricular Hemorrhage (SEH-IVH) Caused by capillary bleeding in the germinal matrix Most frequent location is the thalamic-caudate groove Continued subependymal (SEH) bleeding pushes into the ventricular cavity (IVH) & continues to follow CSF pathways causing obstruction Treatment: Ventriculoperitoneal Shunt Since 70% of hemorrhages are asymptomatic, it is necessary to scan babies routinely Small IVH’s may not be seen from the anterior fontanelle because blood tends to settle out in the posterior horns Risk Factors Pre term infants Less than 1500 grams birth weight
Hemorrhagic Pathology Grades Based on the extension of the hemorrhage Ventricular measurement Mild dilation: 3-10 mm Moderate dilation: 11-14 mm Large dilation: greater than 14mm Grade I Without ventricular enlargement Grade II Minimal ventricular enlargement Grade III Moderate or large ventricular enlargement Grade IV Intraparenchymal hemorrhage
Hemorrhagic Pathology Grade I
Hemorrhagic Pathology Grade II
Hemorrhagic Pathology Grade III
Hemorrhagic Pathology Grade IV
Intraparenchymal Hemorrhage Brain parenchyma destroyed Originally considered an extension of IVH, but may actually be a primary infarction of the periventricular and subcortical white matter with destruction of the lateral wall of the ventricle. Sonographic Finding Zones of increased echogenicity in white matter adjacent to lateral ventricles
Intracerebellar Hemorrhage Types Primary Venous Infarction Traumatic Laceration Extension from IVH Sonographic Findings Areas of increased echogenicity within cerebellar parenchyma Coronal views through mastoid fontanelle may be essential to differentiate from large IVH in the cisterna magna
Epidural Hemorrhages and Subdural Collections Best diagnosed with CT because the lesions are located peripherally along the surface of the brain.
Ischemic-Hypoxic Lesions Hypoxia: Lack of adequate oxygen to the brain Ischemia: lack of adequate blood flow to the brain Types Selective neuronal necrosis Status marmoratus Parasagittal cerebral injury Periventricular leukomalacia (PVL), white matter necrosis (WMN), or cerebral edema Focal brain lesions (occurs when lesions are distributed within large arteries) Sonographic Findings Areas of increased echogenicity in subcortical and deep white matter in the basal ganglia
Ischemic-Hypoxic Lesions Periventricular Leukomalacia (PVL) or White Matter Necrosis (WMN) Most important cause of abnormal neurodevelopment in preterm infants Early chronic stage Multiple cavities develop in necrotic white matter adjacent to frontal horns Middle chronic Stage Cavities resolve and leave gliotic scars and diffuse cerebral atrophy Increased Echogenicity Late chronic stage Echolucencies develop in the echolucent lesions corresponding to the cavitary lesions in the white matter (cysts)
PVL or WMN 1 2 4 3
Brain Infections Common infections referred to by TORCH T: Toxoplasma Gondii O: Other (Syphilis) R: Rubella Virus C: Cytomegalovirus H: Herpes Simplex Type 2 Consequences Mortality Mental Retardation Developmental Delay
Ependymitis and Ventriculitis Ependymitis Irritation from hemorrhage within the ventricle Occurs earlier than ventriculitis Sonographic Features Thickened, hypoechoic ependyma (epithelial lining of the ventricles) Ventriculitis Common complication of purulent meningitis Sonographic Findings Thin septations extending from the walls of the lateral ventricles.
Neonatal Cranial Ultrasound Ms. Assema Lalzad, Senior Sonographer, Department of Medical Imaging, St. Francis Xavier Cabrini Hospital; Mercy Hospital for ...
... Contact Us | Careers ... Neonatal cerebral ultrasound. Cambridge University Press (1997). ... Coronal Views.
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forming cranial US on neonatal units in two regions of the United Kingdom. Design All neonatal and special care baby units where