Cranial usg final.pptx
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Neonatal cranial ultrasonography for M. D Radiodiagnosis
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Cranial usg final.pptx
- 1. Cranial Ultrasonography CHAIRPERSON : DR ASHWIN PATIL CO-CHAIRPERSON : DR ABHINANDAN RUGE PRESENTER : DR NISHITHA A
- 2. Objectives Introduction Advantages Indication Method Anatomy Normal Anatomical variants mimicking pathologies Pathology Transcranial Doppler Limitations
- 3. Introduction An extremely important neuroimaging technique in neonates & infants. Well-established technique in providing clinically important information in a convenient and safe bedside environment First line investigation in assessment of the unwell or hemodynamically unstable neonate. Best line of investigation : MRI
- 4. Evolution of Cranial USG EVOLUTION OF CRANIAL USG <1980 1980-2000 1990-2000 B – MODE USG TRANSCRANIAL DOPPLER A – MODE USG
- 5. Advantages of cranial ultrasound o Safe o Bedside- compatible o Reliable o Early imaging o Serial imaging : Brain maturation Evolution of lesions o Inexpensive o Suitable for screening
- 6. Indications Screening for hemorrhage or parenchymal injury Premature infants – all < 1500 g or < 32 weeks gestation Follow-up of hemorrhage, post-hemorrhagic ventricular dilatation and peri- ventricular leucomalacia Congenital malformations of brain Follow-up of antenatally detected brain abnormalities Cranial dysmorphism Sudden deterioration in clinical conditions Signs and symptoms of CNS disorders
- 7. Methods of cranial ultrasonography: All aseptic precautions should be followed Must be done in a warm environment When baby is quiet or after feeding Baby is placed in the supine position Care should not be taken to not move the infant Transducer should be cleaned thoroughly before and after the examination Coupling gel is applied to the transducer
- 8. Methods of cranial ultrasonography: Select the appropriate probe Select the appropriate preset Adjust the depth, gain and time gain compensation settings Probe is then firmly placed over the fontanelle Pressure over the anterior fontanalle should be avoided, especially in the premature critically ill neonate
- 9. Types of probes High-frequency sector/phased array transducer with a small footprint probe • Transducers: 5 – 7.5 – 10 Mhz • Preterm : 7.5 Hz • Standard examination : use 7.5 – 8 MHz Higher frequency linear transducer (10 Mhz) in tiny premature infant and/or superficial structures Lower frequency sector / linear transducer ( 5 Mhz) in Large infant, thick hair, and/or deep structures
- 10. ANATOMY
- 11. ANATOMY
- 12. SONOGRAPHY PRINCIPLES The normal brain is always nearly symmetric. But symmetric is NOT ALWAYS normal. White matter looks like white matter, Grey matter looks like grey matter. (Grey matter – Hypoechoic, White matter – Hyperechoic) CSF – Anechoic Choroid plexus / small hemorrhages / areas of infarct – Hyperechoic Echogenicity of white matter < Echogenicity of choroid plexus Subarachnoid space – Anechoic with vessels Subdural space – Anechoic without vessels
- 13. SONOGRAPHY PRINCIPLES VISIBLE LAYERS OF THE NORMAL CORTEX
- 14. KEY SONOGRAPHIC STRUCTURES Interhemispheric fissure Sylvian fissure Cavum septum pellucidum (CSP) Corpus collosum Basal ganglia ( caudothalamic groove) Ventricular system Cerebellum
- 15. Interhemispheric Fissure • Deep groove that separates the hemispheres • Falx cerebri • Midline structure
- 16. SylvianFissure • Deep horizontal groove • Aka “ lateral sulcus” • Insula is buried deep to it
- 17. Corpus Callosum • Horizontal bundle of nerve fibers connecting both hemispheres • Largest white matter structure consisting of more than 200 axons • Components: Rostrum Genu Body Splenium
- 19. Basal Ganglia • Collection of grey matter structures at the base of the brain • Components: Caudate Nucleus Globus pallidus Putamen • Caudothalamic groove
- 21. Ventricular System • Series of chambers in the brain filled with cerebrospinal fluid. • Contains Choroid Plexus • Components: Paired lateral ventricles Third ventricle Fourth ventricle
- 22. LATERAL VENTRICLE FORAMEN OF MUNROE THIRD VENTRICLE CEREBRAL ACQUEDUCT FOURTH VENTRICLE FORAMEN OF LUSCHKA AND MAGENDIE SUBARCHANOID SPACE SAGITTAL SINUS
- 23. LATERAL VENTRICLE THIRD AND FOURTH VENTRICLES
- 24. Choroid Plexus • Network of epithelial cell, capillaries and connective tissue • Creates CSF and filters waste • Located in lateral, 3rd and 4th ventricles • Hyperechoic. 3 DOT SIGN
- 25. Acoustic windows Anterior fontanelle - Most cranial ultrasounds are performed used till 12 – 14 months) Supplemental windows : 1. Posterior fontanel 2. Mastoid fontanel 3. Temporal window Imaging through a supplementary window should be performed if any abnormality is detected in sagittal or coronal plane.
- 27. CORONAL VIEWS Transducer should be placed in the middle of the Anterior fonatnel Plane - passing from ear to ear. Marker on transducer should point to baby’s right Transducer is angled as far forward and backward as possible to scan coronal images in sequential manner
- 28. CORONAL PLANES C1 – Frontal lobes C2 – Frontal horns of lateral ventricle C3 – Third ventricle C4 – Posterior to foramen of Monro( level of cerebellum) C5 – Level of trigone of lateral ventricles C6 – Level of occipital lobes
- 29. INTERHEMISPHERIC FISSURE FRONTAL LOBES ORBITS C1 – Frontal lobes
- 30. INTERHEMISPHERIC FISSURE CSP LATERAL VENTRICLES SYLVIAN FISSURE C2 – Frontal horns of lateral ventricle
- 31. CORPUS CALLOSUM COROID PLEXUS LATERAL VENTRICLE THIRD VENTRICLE TEMPORAL LOBE C3 – Third ventricle
- 32. TENTORIUM CISTERNA MAGNA C4 – Level of trigone of lateral ventricles
- 33. PERIVENTRICULAR BLUSH CHOROID PLEXUS C5 – Trigone level
- 34. PARIETAL LOBE OCCIPITAL LOBE PVWM C6 – Level of occipital lobes
- 35. SAGITTAL PLANE Transducer rotated at 90 degrees for scanning in sagittal plane Probe should be parallel to the AP diameter of the cranial vault, marker should point towards baby’s noise.
- 37. ANGLED PARASAGITTAL VIEW PARIETAL LOBE CAUDATE NUCLEUS THALAMUS TEMPORAL LOBE OCCIPITAL LOBE CHOROID PLEXUS
- 38. TANGENTIAL PARASAGITTAL VIEW SYLVIAN FISSURE PARIETAL LOBE TEMPORAL LOBE
- 40. Superior coronal view Middle coronal view Inferior view
- 42. TEMPORAL WINDOW
- 46. Normal variants mimicking pathologic abnormalities 1. Persistent fluid filled spaces 2. Mega cisterna magna 3. Assymetric ventricular size 4. Choroid plexus variants 5. Periventricular cystic lesions 6. Hyperechoic white matter pseudolesions or periventricular halo 7. Immature sulcation in premature infants 8. Lenticulostriate vasculopathy 9. Calcar avis
- 47. Persistent fluid filled spaces Common finding in healthy neonates Occasionally persist into adulthood and are a normal variant of no significance Include: 1. cavum septi pellucidid ( CSP) 2. cavum vergae 3. cvaum veli interpositi
- 48. Cavum Septum Pellucidum • Midline fluid filled structure between anterior horns of lateral ventricle • Fetal neurodevelopment marker • Usually fuses by 6 months, persists in 15% of adults
- 49. Cavum verge • Continuation of CSP posteriorly • Present : 30% of infants <1% of adults
- 51. Cavum VellumInterpositum • Supratentorial cystic structure • Antero-inferior to splenium of CC • Color doppler : to rule out Vein of Galen aneurysm
- 52. Mega Cisterna magna The typical cisterna magna is less than 8 mm in both the sagittal and axial planes. A mega cisterna magna measures greater than 8 mm and is seen in 1% of post-natally imaged brains. A mega cistern magna is a normal variant distinguished from an arachnoid cyst by its lack of mass effect .
- 53. Assymetric ventricular size • Normal ventricles measure less than 10 mm in transverse diameter • 60% of full term and 30 % of premature infants having ventricles smaller than 2- 3 mm. • Asymmtery between the sizes of the ventricles has been observed in 20 – 40 % of infants.
- 54. Choroid plexus variants • Choroid cysts smaller than 1 cm are incidentally noted in 1 % of infants at autopsy. • At prenatal US, it is predictive of autosomy 18 especially if large,and bilateral • Variation sin shape of choroid plexus can be seen – lobular or bulbous variants
- 55. Connatal cysts String of pearls Also called subfrontal / frontal horn cysts Seen most often during early postnatal period and may regress spontaneously Appear as bilateral symmetric cysts adjacent to the frontal horns, just anterior to the foramina of Monroe. Usually appear in multiples and appear as a string of pearls.
- 56. Hyperechoic white matter pseudolesion /periventricular halo Apparent echogenic areas that are visualized only in one plane Occur as artifacts due to anisotropic effect Additional images obtained at a 90 degree angle resolve the finding and prevent misinterpretation. Periventricular white matter pseudolesions and halos are normally less echogenic than the adjacent choroid plexus
- 57. Immature sulcation Infants born before the 24th week possess a smooth cerebral convexity exhibiting only the occipito-parietal and sylvian fissures A diagnosis of lissencephaly should not be made in newborn < 24 weeks of gestation
- 58. Lenticulostriate Vasculopathy Nonspecific thickening of the lenticulostriate artery walls secondary to a variety of pathologic conditions and infections Seen on sonography as unilateral or bilateral branching, linear or punctate increased echogenicity within the thalami Resolves in 32 – 50 % of premature infants.
- 59. Calcar Avis It is a paramedian protusion of the calcarine gyrus into the medial aspect of the lateral vent at the junction of trigone with the occipital horn. It may simulate a intraventricular hemorrhage.
- 60. PATHOLOGY
- 61. GerminalMatrix • Fetal structure that involutes by 36 weeks • Highly vascularized structure • Located in the subependymal region of the caudo-thalamic groove • Origin of hemorrhage in premature infants.
- 62. Intra-cranial hemorrhage – Germinal matrix hemorrhage More common in premature infants (50%) Most common neurological complication in preterm infants 20 – 25 % are asymptomatic 90% of hemorrhages occur in first week of life, 1/3rd on first day Follow with weekly Ultrasound to evaluate for hydrocephalus
- 63. Grades :
- 64. Grade I
- 65. Grade II DAY 0 DAY 3
- 66. Grade III
- 67. Grade IV
- 68. Grade IV – Intra-ventricular hemorrhage evolution
- 69. Periventricular leucomalacia(PVL) or White matter necrosis ( WMN) Hallmark of hypoxic ischemic insult in preterm neonates Leuco : white, malacia : softening It is a white matter disease that affects the periventricular zones. Causes : Ischemia , infection, vasculitis PVL presents as areas of increased periventricular echogenicity. occurs most commonly in premature infants (<33 WOG (38% PVL) and <1500 g birth weight (45% PVL).
- 70. DeVries classification of PVL grading • Grade I : Prolonged periventricular flare present for 7 days or more. • Grade II : Presence of small – localized fronto-parietal cysts. • Grade III : Extensive periventricular cystic lesion involving occipital and fronto-parietal white matter • Grade IV : Areas of extensive sub-cortical cystic lesions.
- 72. Grade I
- 73. Grade II
- 74. Grade III
- 75. Grade IV
- 76. Pattern of hypoxic ischemic injury Neonate Moderate Severe Premtaure Periventricular leucomalacia Thalamic, basal ganglia and brainstem Term Parasagittal white matter in cortex Thalamic, basal ganglia, brainstem and perirolandic white matter
- 77. Hydrocephalus Excessive accumulation of CSF in the ventricular system or subarachnoid spaces or both. Results from imbalance in absorption and production of CSF or due to an obstruction to the free flow of CSF. Types : 1. Communicating ( Extra- ventricular obstruction) 2. Non- communicating ( Intra- ventricular obstruction)
- 78. Ventricular measurements ANTERIOR HORN WIDTH THALAMO-OCCIPITAL DISTANCE VENTRICULAR INDEX Normal < 3 mm Mild ventriculomegaly 3 – 5 mm Moderate ventriculomegaly 6 – 10 mm Severe ventriculomegaly > 10 mm
- 79. LEVENE INDEX : Up to 40 weeks * Absolute distance between the falx and the lateral wall of the anterior horn in the coronal plane at the level of third ventricle. VENTRICULAR INDEX : > 40 weeks *Ratio between the lateral sides of the ventricles and the biparietal diameter.
- 80. CRANIAL DOPPLER SONOGRAPHY Vessels identified in Cranial Doppler : ACA ( A1 and distal segment), internal carotid artery and basilar artery, internal cerebral veins and vein of Galen Superior sagittal sinus and straight sinus AF and trans-temporal (squamous portion of temporal bone) approach Circle of willis is best seen through transtemporal approach
- 81. Brain – low resistance vascular bed. Continuous forward flow should be seen in arteries in both systole and diastole Doppler Imaging : o Circle of Willis o Region of vein of Galen Normal RI : 0.6 – 0.9 <0.5 and > 0.9 : Abnormal
- 82. Resistive index • Highest in premature and decreases upto 2 years of age. • General approximation : Premature – 0.8 Term – 0.7 1 year – 0.6 2 year – 0.5
- 83. TYPES OF CYSTS LOCATION CONNATAL CYST At or just below the supero-lateral angles of frontal horn or body of lateral ventricles and anterior to foramen of Monroe SUBEPENDYMAL CYST Below the external angles of frontal horn or body of lateral ventricles and posterior to foramen of Monroe PERI- VENTRICULAR LEUCOMALACIA Above the angles Periventricular cystic lesions
- 84. Congenital brain anomalies Disorders of organogenesis Disorders of diverticulation Disorders of sulcation and migration Disorders of histiogenesis Chiari II malformation Dandy walker malformation Corpus callosal agenesis Schizencephaly Lissencephaly Holoprosencephaly Vein of Galen malformation Pellucidal agenesis
- 90. Schizencephaly
- 91. Lissenecephaly
- 92. Vein of Galen Malformation • Fistulous connection between cerebral arteries and median prosencephalic vein. • m/c AV malformation in neonatal period • 2 types : Choroidal - 90%, presents in neonate as chf and intracranial bruit Mural – presents in infancy with developmentak delay, seizures and hydrocephalus
- 93. Limitations Image quality is dependent on the size of the acoustic window available Evaluation of superficial structures id difficult Myelination is not visualized Diffuse white matter injury are not very well detected Presence of scalp hair
- 95. References 1 . Rumack CM, Levine D. Diagnostic ultrasound. Elsevier Health Sciences; 2017 Aug 8. 2. Allan, P.L., Baxter, G.M. and Weston, M.J., 2011. Clinical Ultrasound, 2- Volume Set E-Book: Expert Consult: Online and Print. Elsevier Health Sciences. 3. AIIMS – MAMC – PGI’s Comprehensive textbook of Diagnostic Radiology
- 96. THANK YOU
Editor's Notes
- Describe a screening head ultrasound Know the screening protocol for cranial usg Perform a head ultrasound
- Role of MRI : can detect brain maturation, can detect lesions that are difficult to be detected on sonography Allows detection of diffuse and noncystic white matter lesions in preterm infants and diffusion weighted imaging allows very early detection of hypoxic ischemic brain injury.
- A - mode : for demonstration of midline shift B – mode : for pathologies
- Safe – no ionizing radiation Incubator safe , no hassle of shifting the baby
- Premature infants : m / c cause of intra-cranial hemorrhage Seizures, hypotonia, microcephaly and unexplained poor feeding at term Aims : Exclude/demonstrate cerebral pathology Assess timing of injury Assess neurological prognosis Help make decisions on continuation of neonatal intensive care Optimize treatment and support
- – hand washing, sterile gowns caps, masks and gloves
- AF is small : phased array transducers of small footprint and wide insonation angle ( 140 degrees) 7.5 – optimal visualization of per-and intra- ventricular areas of brain Superficial structures : cortex, subcortical white matter, sas and sss Deeper structures : posterior fossa and basal ganglia in full term infants Sector probe with small footprint : provides a sector filed of view, generates a cone shaped image originating from a small apex
- The brain is divides into 3 main parts- the cerebrum/ forebrain : most cephaliod portion , cerebellum(hindbrain) and the brainstem which starts from below the crebellum all the way down to the spinal cord/canal and consists of pons, midbrain and medulla. The bra in has many convolutions called the sulci nd gyri,these increase the surface area of the brain accumulating more brain tissue. The cerebrum is divided into 4 sections: frontal and parietal : by central sulcus…frontal, parietal and temp by lateral sulcus/ sylvian fissure. The cerebrum is also divided into 2 hemispheres : the right and the left.. These hemispheres are connected by corpus callosum (posterior view of a sheep brain showing CC, rt nd left hemispheres, cerebellum and spinal cord)
- Translation of brain anatomy to sonography needs understanding of sonographic physical principles. NORMAL BRAIN IS ALWAYS NEARyT SYMMETRIC. This fact allows for detection of early changes of infarction or focal ischemia. The superficial pia mater should be seen as a thin, well-defined hyperechoic layer immediately overlying the hypoechoic cortical gray matter, which in turn overlies the hyperechoic white matter. . SUBARCHANOID SPACE : contains many vessels unlike subdural. it is symmeteric This image displays normal gray- white matter differentiation in a term neonate. (rule of 3 : all these 3 layers are usually seen an are distinguishable) SUBARCHANOID SPACE : contains many vessels unlike subdural. it is symmeteric (PRESSURE OVER THE ANTERIOR FONTANELLE SHOULD BE AVOIDED IN PREMATURE INFANTS – AS IT CAN SUBARCHANOID SPACE OBLITERATION)
- The superficial pia mater should be seen as a thin, well-defined hyperechoic layer immediately overlying the hypoechoic cortical gray matter, which in turn overlies the hyperechoic white matter This image displays normal gray- white matter differentiation in a term neonate. (rule of 3 : all these 3 layers are usually seen an are distinguishable) (PRESSURE OVER THE ANTERIOR FONTANELLE SHOULD BE AVOIDED IN PREMATURE INFANTS – AS IT CAN SUBARCHANOID SPACE OBLITERATION)
- These are the structures which we see almost always and are important to rule out anomalies and for orientation to landmarks
- Sonographic image showing IF : red line and rt + left cerebral lobes/hemispheres Anatomical drawing of the same. Within the interhemispheric fissure, we have falx cerebri – which is the invagination of the dura matter, it goes down into the groove (dura matter is covering of the brain/ part of meninges) -- this is an anatomical section showing the falx and surrounding dura. Green colour – tentorium that separates cerebrum and cerebellum
- This is a deep horizontal fissure, where as interhemi fissure was a deep longitudinal and midline fissure.. this is horizontal and lateral IT IS ECHOGENIC - COZ OF THE PRESENCE OF MCA IN IT (Insula : involved in consciousness/related to emotions: empathy,compassion / reg of body homeostasis:taste,perception/motor control to name a few)
- It is a very important and large structure that connects both hemispheres…(picture :we can see the fibers cross over, this is one hemi and other hemisphere, they are all the nerve fibers—they allow communication between 2 hemispheres) IMPORTANT FOR EYE MOVEMENTS, COGNITION, AND TACTILE LOCALIZATION REPORTEDLY LARGER IN FEMALES
- Sonographic coronal image showing CC and white matter tracts going out ( inter fissure, lat vent, CSP , 3rd vent) Sonographic sagittal image showing the components .
- Important in motor learning/ eye movements/motivation. Between the caudate and thalamus- we have caudothalamic groove which is important for sonography- site for germinal bleeds. caudate : hypoechoic
- Echogenic choroid plexus.. CTG is the area where germinal cortex is present.(which well discuss it a little later) Any echogenicities same or more ehogenic to CP when seen in CTG indicated haemorrhage.
- In very young fetuses, vent system has germinal matrix all around
- Points Typically in USG we can only see CP in lat vent and in the roof of the 3rd vent , 3 echogenic foci : 3 DOT SIGN Choroid plexus in a premature infant has a lumpy bumpy appearance with prominent echogenicity. Shouldn’t be confused with a intra-ventricular clot. Echogenic choroid plexus is not seen in the frontal horn anterior to the foramin of monro or occipital horns. Doppler evaluation – chroid plexus flow is seen and absent in hemorrhagic clot.
- AF : opens till 2 years but we scanning is : 1till 2-14months PF : opens upto 3months
- Excellent window to image the supratentorial part of the brain Located at the junction of coronal and sagittal sutures Remains open for the first 12 – 14 months of age. (Parasagittal view – probe to be angled right and left fro mid-sagittal view
- In very premature babies we can also see the outline of the lens when angulated anterior enough
- @ level of frontal horn Lateral ventricles are larger in preterm infants CSP – fkuid filled space bw frontal horns Cc – lies superior to CSP giving rise to tram-line appearance Caudate nucleus present below lateral ventricle s
- Third ventricle seen b/w lateral ventricles and csp Foramen on monro is seen in this view Sylvian fissure is seen in this plane . Y-shaped structure In term infants and wide-open in preterm infants Important view to assess basal ganglia for edema, ischemia and hemorrhage. Lenticulostriate vasculopathy
- CP : LARGEST PART WE SEE IN LAT VENT CALLED AS GLOMUS, anatomical depection of it is seen in this – very lumpy looking tissue .. It is key to notice the perivent white matter. / aka peritrigonal blush (post and superior to trigone of vent) PVWM : IS HOMOGENOUS IN ECHOGENICITY AND should be EQUAL OR LESS ECHOGENIC THAN CP. IF HYPERECHOIC THAN CHOROID PLEXUS, we need to think of ischemias : PVL Ventricular cavities should diverge at this plane, if they are seen parallel, cc dysplasia should be suspected
- (There are many parallel fibers in this region and coz of the placement of the probe in coronal section, it producses wave which hit these fibers at 90 degrees/ perpendicular : creating a blush like appearance )
- First view : midline Second : thru caudothalamis groove / para sagittal view Thiird : at the level of PVWM and slyvian fissure / tangential para sagittal
- Midline parasagittal : Csp cavum vergae ( if present) Corpus callosum 3rd ventricle with massa intermedia Cerebral aqueduct Fourth ventricle Cerebellum brainstem
- At the level of CTG .. Any echogenicity in that area around 1 cm : germinal matrix haemorrage.. Choroid plexus usually starts 1/3 rd after the begenining of the thalamus The choroid tucks up in the caudothalmic groove of the lateral ventricle. It does not extend beyond the caudothalamic grooves into the frontal horns. Important view to assess basal ganglia and lenticulostriate vasculopathy
- Further angulation of the transducer laterally results in a section lateral to the lateral ventricles. The sylvian fissure is the landmark in this view At the level of insular cortex/ sylvial fissure. Structures seen : parietal lobe, temporal lobe Assess periventricular white matter, periventricular flare and cystic periventricular leucomalacia
- Used to visualized occipital horns, glomus of cp and periventricular white matter Located at jn of sagittal and lamboid suture. Fuses by 3 months
- CA indicates calcar avis; Ch, choroid plexus; CH, cerebellar hemispheres; LV, lateral ventricle trigone; OH, occipital horn; OL, occipital lobe; SA, subarachnoid space; and T, tentorium. Occipital horns are anechoic as they have no choroid plexus.
- Baby with their heads laying down, he most dependent portion of the vent susytem is the occipital horn..so if we are unsure of blood in the vent system , we can use this view and any echogenicity in occ horns indicates hemorrhage These planes are extremely useful for detecting dependently layering clot and clot attached to the choroid plexus. So CP on doppler exhibits vascularity but clot: lack of vascular flow (peritrigonal blush : fibers are almost parallel so no blush is seen usually, in suspected cases of PVL this view can be used to rule out )
- Right above the ear where the ear meets temporal part of the skull. Circle of willis can be visualized. Axial view , similar to view calculating bpd in anc
- Posterior to the ear behind the helix. At the jn of temporal, parietal and occipital bones. best view for cerebellum, brainstem ( pons and midbrain) May not fuse till 2 years of age
- Place the probe parallel to the ear to obtain a coronal view. Sweep the probe back and forth to identify the cerebellar hemispheres, vermis, third and fourth ventricle, pons and cisterna magna.VERMIS IS ECHOGENIC.. Cerebellar hemispheres are hypoechoic compared to vermis.
- Fuses by 3-6 months. ( fusion starts from the posterior to anterior – so the first to get obliterated is cavum vergae) ABSENCE IS ASSOCIATED WITH CNS ABNORMALITIES : SEPTO OPTIC DYSPLASIA , CALLOSAL AGENESIS
- This is a diagram showing vent system – deep to it we have CSP and CV which is a continuation of CSP (posterior cystic portion )…CV is present in some babies and is continuation of CSP and it goes all the way down to the end of CC.)
- Anterior to foramen of monro – csp Posterior to monro – cavum vergae
- N THIS BABY CSP AND CV ARE NOT EVEN PRESENT- THEY ARE OBLITERATED. CVI : structure is good to place doppler to rule out vein of galen aneurysm or any other venous aneurysms NOT ASSOCIATED WITH ANY CONGENITAL ANOMALIES Not seen after 2 years of age normally Dd : arachnoid cyst
- CISTERNA MAGNA : normal 3– 8mm , unlike archanoid cyst it doesn’t cause any mass effect when enlarged . And it can be diff from dandy walker by visualization of vermis.
- ASYM VENT SIZE: ventricular size smaller as infants mature .. Normal <10mm in transverse.. Asym vent size can be diff from entriculomegaly(colpocephaly) as colpo co-occurs with agenisis of corpus callosum / chiari 2 malformations. Colpocephaly - disproportionate prominence of the occipital horns of the lateral ventricles. Radiologically, diagnosis of colpocephaly becomes more likely when the ratio of the posterior horn to anterior horn of lateral ventricle width (P/A ratio) is ≥3. Dd for colpocephaly – normal pressure hydrocephalus
- The choroid plexus does not extend into the frontal or occipital horns, so hyperechoic material in these areas should suggest pathology. Isolated cysts and measuring less than 1cm, they are considered a benign finding When choroid cysts are found to be multiple, bilateral, or greater than 1 cm in size, this may suggest a chromosomal abnormality .
- Connatal cysts are always found in immediate proximity with the frontal horns where they are found in multiples and exhibit a string of pearls appearance ..they undergo Spontaneous regression.. Located at the superolateral margin of junction of frontal horn and body of lateral ventricles (Believed to be caused by deficient coarctation of the ventricles)
- Anisotropy effect is an ultrasound artifact where an echogenicity is seen / echogenic structure is seen due to an oblique insonating angle and this disapperas when the plane is changed.
- @24wks : occipital fissure is seen.. @28wks : cingulate gyrus and at around 30 wks sulcal branching occurs and sulci and gyri are seen. Lack of sulcation in term – abnormal. Lack of cingulate gyrus – corpus callosal agenesis Lissencephaly is a heterogeneous group of disorders of cortical formation characterized by a smooth brain, with absent or hypoplastic sulci and is strongly associated with subcortical band heterotopia ( this condition is characterized by a band of grey matter located deep to and roughly paralleling the cortex, with either normal or pachygyric overlying cortex) Pachygyria – broad gyri
- Insignificant Depicts insult to the neonatal brain Seen with torch, neonatal hypoglycemia, fetal alcohol syndrome, uncomplicated prematurity
- CALCAR AVIS : it is a paramedian protusion of the calcarine gyrus into the medial aspect of the lateral vent at the junction of trigone with the occipital horn. it may simulate a intraventricular hemorrhage. A, AF parasagittal view shows a rounded masslike image mimicking an intraventricular clot within the occipital horn (arrow). B, PF parasagittal view we can see that the mass is the calcar avis (arrow) DUE TO ITS continuity with the occipital white matter and the calcarine fissure (CF).
- It is a present in premature babies and it is also a fetal structure that involutes by 36 weeks. it is very important coz it is where the bleeds in premature infants begin. It consists of highy vascularized network of premature neural cells which later becomes the glial cells.. These capillaries are very tiny and delicate and can rupture with any change In the fetocerebral vascular perfusion. Rapid change in the blood pressure, these tiny capillaries rupture and blood starts to accumulate in CTG and when it breaks the vent lining or ependymal lining, it enters the vent and becomes IVH. PREMATURE INFANTS LACK BARORECEPTORS. 1st appears at 7th week, maximum at 23 weeks , involute by 36 weeks
- Grade 1 and 2 bleeds generally have a good prognosis. Grade 3 and 4 bleeds have variable long-term deficits, but outcome in grade 3 hemorrhages is usually good when no parenchymal injury has occurred. 80 % of grade 1 progress to garde 2
- intracranial hemorrhage confined to the caudothalamic groove/ sub-ependymal region It is staged as grade 1 hemorrhage., < 1cm In the acute phase these bleedings are hyperechoic, changing to iso- and hypo-echoic with time. Non hemorrhagic hyperechogenicity – infections, term babies
- 80 % of grade 1 progress to grade 2 On the left a grade 2 intracranial hemorrhage. On the coronal image only the cavum septi pellucidi is seen. Both lateral ventricles are filled with blood, but there is no ventricular dilatation. On the left the same patient after 3 days. The ventricles are dilated and clot formation is seen. Secondary hydrocephalus occuring several days after a grade 2 bleed should not be mislabeled as grade 3 hemorrhage. Ependyma is very fragile and ruptures and blood spills inti the ventricles. Blood forms a cast of the ventricle.
- Large Intra-ventricular hemorrhage with ventriculomegaly Ventricular lining becomes echogenic reflecting ventriculitis 20% increase in mortality 35% increase in neurologic deficits Large highly reflective areas fill the ventricles producing a cast like appearence
- Grade 4 intracranial hemorrhage Originally these grade 4 hemorrhages were thought to result from subependymal bleeding into the adjacent brain. Today however most regard these grade 4 hemorrhages to be venous hemorrhagic infartions, which are the result of compression of the outflow of the veins by the subependymal hemorrhage. On the left a grade 4 hemorrhage. There is a large subependymal bleeding but also a large area with increased echogenicity in the brain parenchyma lateral to the ventricle. This is probably the result of a venous infarct. These venous infarctions resolve with cyst formation. These cysts can merge with the lateral ventricle, finally resulting into a porencephalic cyst. On the left a different patient with a grade 4 hemorrhage at a later stage with extensive cyst formation. 50 % increase in mortality, 90 % increase in neurological deficits like cerebral palsy and spastic doiplegia
- Day 1 , Day 2 – No bleed Day 3 – Intra-parenchymal hemorrhage extending into ventricles Day 4 – Intra-ventricular clot ( increasing in size) with periventricular echogenicity suggestive of ischemia and necrosis Day 7 – Clot retraction Day 28 – Cystic encephalomalecic changes.
- In prematures this white matter zone is a watershed zone between deep and superficial vessels, very vulnerable to hypoxic ischemic insult Normally the echogenicity of the periventricular white matter should be less than the echogenicity of the choroid plexus. Detection of PVL is important because a significant percentage of surviving premature infants with PVL develop cerebral palsy, intellectual impairment or visual disturbances. More than 50% of infants with PVL or grade III hemmorrhage develop cerebral palsy.
- Periventricular cysts ar eusually < 2-3 mm and carry poor prognosis
- The term flaring is used to describe the slightly echogenic periventricular zones, that are seen in many premature infants in the first week of life. During this first week it is not sure if this is a normal variant or a sign of PVL grade 1. Flaring persisting beyond the first week of life is by definition PVL grade 1. Follow up is needed to differentiate flaring from PVL grade I. The case on the left shows a premature infant with flaring. At follow up no cyst formation was found and after the first week a normal periventricular white matter was seen.
- PVL is diagnosed as grade 1 if there are areas of increased periventricular echogenicity without any cyst formation persisting for more than 7 days. Increased periventricular echogenicity is however a nonspecific finding that must be differentiated from the normal periventricular halo or normal hyperechoic 'blush' posterosuperior to the ventricular trigones. Suspect PVL if the echogenicity is asymmetric, coarse, globular or more hyperechoic than the choroid plexus. The abnormal periventricular echotexture of PVL usually disappears at 2-3 weeks. PVL can be differentiated from hemorrhages because PVL lacks mass effect.
- The images on the left demonstrate a PVL grade 2 with small periventricular cysts. The echogenicity has resolved at the time of cyst formation. 2% of the preterm neonates born before 32 weeks develop cystic PVL. The severity of PVL is related to the size and distribution of these cysts. Cystic PVL has been identified on cranial ultrasounds on the first day of life, indicating that the adverse event was at least 2 weeks prenatal rather than perinatal or postnatal. US is highly reliable in the detection of cystic WM injury (PVL grade II or more), but has significant limitations in the demonstration of noncystic WM injury (PVL grade I). This deficiency of neonatal cranial US is important, because noncystic WM injury is considerably more common than cystic WM injury.
- PVL is diagnosed as grade 3 if there are areas of increased periventricular echogenicity, that develop into extensive periventricular cysts in the occipital and fronto-parietal region.
- PVL is diagnosed as grade 4 if there are areas of increased periventricular echogenicity in the deep white matter developing into extensive subcortical cysts. PVL grade 4 is seen mostly in fullterm neonates as opposed to PVL grade 1-3, which is a disease of the preterm neonate. Flaring persisting beyond the first week of life is by definition is PVVL garde 1. Cystic spaces that replace brain tissue with wihite matter necrosis
- AHW defined as the diagonal width of the anterior horn measured at its widest point in the coronal plane), and thalamo-occipital distance (TOD) (defined as the distance between the outermost point of the thalamus at its junction with the choroid plexus and the outermost part of the occipital horn in the parasagittal plane. Ventricular index - Ratio between the lateral sides of the ventricles and the biparietal diameter.
- FRONTAL HORN RATIO RIGHT : THERE IS BALOONING OF THE VENTRICLES and the INDEX MEASUREMNETS UNDERESTIMATES THE SEVERITY OF THE VENT WIDENING THESE MEASUREMENTS CAN BE COMPARE TO THE REFERENCE CURVE AND ARE QUITE USEFUL FOR FURTHER FOLLOW UP.
- Color Doppler imaging is used to screen the vasculature for patency and resistance to flow in cerebral veseels In the coronal : we look for circle of willis with internal carotids / MCA/ ACA ..In the sagittal : sagittal sinus and vein of galen Circle of willis can be seen from transtemporal also if fontanelle are closed. Adv of transtemporal view is PCA can also be clearly seen
- RI : decreases with the age ( from 0.9 to 0.5) Lower values may indicate acute hypoxia or ischemia, which may trigger increased diastolic flow through cerebral vasodilation. Higher values may suggest cerebral swelling where intracranial pressures rise higher than systemic pressures leading to decreased diastolic flow
- Subependymal cysts and germinolytic cysts both occur at caudothalamic groove and Subependymal cysts are the sequlae of germinal matrix hemorrhages and congenital geminolytic cysts are commonly seen in metabolic disorders maternal cocaine consumption.(zellwegers), neurotropic infection, (cmv, rubella),
- Histogenesis: Development of cells into tissues. Organogenesis: Development of tissues into organs. Neural tube closure (dorsal induction: 3-4 weeks’ gestation) Diverticulation (ventral induction: 5-6 weeks’ gestation) Diverticulation :
- Posterior fossa cyst commun icating with 4th ventricle ( arachnoid cyst and enlarged foramen magnum do not) Large posterior fossa Hypoplastic cerebellar vermis and laterally displaced cerebellar hemispheres Frequently associated with other anomaies Image :There is an enlarged posterior fossa with a large CSF cystic space communicating with the 4th ventricle. The vermis is not identified and suspected to be absent or hypoplastic. There is high attachment of the tentorium. The anterior and mid-body of corpus callosum are present. Findings are most consistent with a Dandy-Walker malformation.
- Batwing configuration of frontal horns ( Small posterior fossa with low-lying tentorium Interdigitating gyri Large massa intermedia Chiari Imalformation is simply the downward displacement of the cerebellar tonsils, without displacement of the fourth ventricle or medulla. Chiari II malformation is the most common and of greatest clinical importance because of its almost universal association with myelomeningocele. Chiari III malformation is a high cervical encephalomeningocele in which the medulla, fourth ventricle, and virtually the entire cerebellum reside. Classic sonographic findings of the Chiari II malformation involve the entire brain. Anterior and inferior pointed frontal horns- Batwing configuration Enlarged lateral ventricles with occipital horns larger than frontal horns- Colpocephaly Third ventricle appearing only slightly enlarged Enlarged massa intermedia fills third ventricle. Elongation and caudal displacement of fourth ventricle, pons, medulla, and vermis Nonvisualized fourth ventricle because of compression Partial absence of septum pellucidum Interhemispheric fissure Wide, especially after shunting Interdigitation of gyri causes serrated appearance Ansence of corpus callosum Hydrocephalus 100 % have myelomeningocele
- 80 % have associated anomalies Parallel lateral venticlees Elevated 3rd ventricle Absent cingulate gyrus and sulcus Sunburst sign – radially arranged sulci Probst bundles impress upon lateral ventricles ( failure to fuse)
- Rare congenital brain malformation resulting from incomplete separation of two hemispheres due to failure of midline cleavage of prosencephalon Types : lobar, alobar and semilobar ( lobar – least severe type – midline abnormalities – fusion of cingulate gyrus and anterior frontal lobes) Alobar – single large posteriorly located ventricle and fused thalami Single ventricle and fused thalami. No falx or interhemispheric fissure Right – mr image
- Semilobar – intermediate between alobar and lobar Most commonly fused at the thalami and anteriorly Can have associated facial anomaly Partially separated thalamus Hypoplastic falx and interhemispheric fissure
- Rare cortical malformation manifesting as a grey matter lined cleft( single or bilateral) extending from ependymal to pia mater i.e from cortex to ventricular system Type 1 : closed lip Type 2 : open lip – easily diagnosed on usg an echo –free cavity extends from surface of brain to fuse with lateral wall of lateral ventricle Image : open-lip schizencephaly show bilateral clefts (c) with wide openings to the ventricular (v) system.
- Lack of gyration and sulcation Thickened cortex Colpocephaly Homogenous or pseudoliver appearance to the brain parenchyma Figure of 8 appearance due to shallow sylvian fissure Can result from intra-uterine infection
- Small acoustic win dows can affect image quality and some structures and abnormalities remain difficult to visualize.