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88 Cards in this Set
- Front
- Back
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Rhombencephalon
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Anencephaly
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Lethal
Means “absence of brain” Caused by the neural tube failing to close at the cranial end |
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The most common NTD
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Anencephaly
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Anencephaly causes
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: isolated (spontaneous, low folic acid), genetic (T13, T18), Syndrome related (Meckel-Gruber, ABS)
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ANENCEPHALY Sonographic and Clinical Signs
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No brain or cranial vault above level of orbits
Brainstem remains Mostly in females Elevated AFP Frog Like appearance Polyhydramnios Other NTD’s common Often contiguous with cervical spine defect |
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Precursor to anencephaly
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Exencephaly
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Lack of cranial vault leads to brain exposure to amniotic fluid.
Exposure and movement lead to destruction of brain content |
Exencephaly
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Exencephaly Most commonly seen in
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1st trimester
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Exencephaly US
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Cephalocele
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BONY DEFECT: Opening in skull that allows brain tissue to protrude through
Usually posterior (occipital) |
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Cephalocele Top differential:
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Cystic hygroma
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cephalocele Imaging
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Bony defect with paracranial mass
Diverse appearance dependent on what is herniating Gyral pattern Cyst like: prolapsed 4th ventricle Ventriculomegaly 70-80% Microcephaly 25% Polyhydramnios AND oligohydramnios Other CNS anomalies common |
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cephalocele Imaging
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cephalocele Imaging
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Frontal Cephalocele
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Frontal Cephalocele
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Usually small in size
Appears as forehead mass in profile view May have hypertelorism |
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Agenesis of the Corpus Callosum
Abnormal anterior cerebral artery branching along region of CC |
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Agenesis of the Corpus Callosum
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Absent Corpus Callosum
Absent CSP Elevated and dilated 3rd Ventricle Parallel lateral ventricles Mild ventriculomegaly with teardrop shape Other CNS anomalies 50% Fetal body anomalies 60% Fetal MRI: finds other anomalies missed on U/S >50% Karyotype recommended |
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HOLOPROSENCEPHALY
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Forebrain (prosencephalon) fails to divide or only partly divides into cerebral hemispheres
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HOLOPROSENCEPHALY Different forms
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Alobar (C-shaped monoventricle, fused thalami)
Semi-lobar Lobar |
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Facial anomalies (proboscis, cyclops, hypotelorism)
Chromosome anomalies (Trisomy 13) |
HOLOPROSENCEPHALY
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Alobar HOLOPROSENCEPHALY
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single monoventricle (cup, ball, pancake look)
Fusion of thalamus Absence of normal incracranial anatomy Facial anomalies 70% Cyclopia – above or below proboscis Proboscis Median clefts |
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ALOBAR
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Alobar
http://www.ultrasoundlink.net/holoprosencephaly-face |
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Semilobar
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Mid-severity within holo
Singular ventricular cavity Partial formation of occipital horns Partial/complete fusion of thalamus Rudimentary formation Absence of some intracranial structures |
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http://www.ultrasoundlink.net/holoprosencephaly-semilobar
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“Mild” end of holo spectrum
Separate hemispheres Separate lateral ventricles Fused fornices Thalami generally separate Face may show mild hypotelorism or be normal |
Lobar
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ALOBAR vs. Lobar US
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ALOBAR vs. Lobar US
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Considered to be the MILDEST form of holo
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Septo-Optic Dysplasia
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Septo-Optic Dysplasia
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Absent CSP – frontal horns of lateral ventricles communicate
Hypoplastic optic nerves Hypothalamic pituitary dysfunction |
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Ultrasound Imaging:
Septo-Optic Dysplasia |
Absent CSP with communicating frontal horns
Mild ventriculomegaly CC present, partially present, thinned |
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Septo-Optic Dysplasia
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Septo-Optic Dysplasia
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Grey matter lined cleft in brain parenchyma
Extends from inner table of skull to ventricle |
Schizencephaly
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Schizencephaly Imaging
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Absent CSP 70% (nearly 100% when bilateral)
If cleft is visible: wedge shaped CSP filled defect through brain parenchyma Apex points towards lateral ventricle Face, profile normal Calcifications seen within interior walls of lateral ventricle of affected side Ventriculomegaly |
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Schizencephaly Imaging
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Schizencephaly Imaging
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Fluid trapped in choroid plexus creates?
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Choroid Plexus Cyst
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Choroid Plexus Cyst resolve by?
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resolve by 32 weeks
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40-50% T18 fetuses have
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Choroid Plexus Cyst
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Not associated with T18 with low-risk patients
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Choroid Plexus Cyst
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Choroid Plexus Cyst size matters
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>10mm increases risk
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Choroid Plexus Cyst
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Narrowing or occlusion of the aqueduct of sylvius causing obstructive hydrocephalus
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Aqueductal Stensosis
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Hydrocephalus
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Narrowing or occlusion of the aqueduct of sylvius causing obstructive hydrocephalus
Hydrocephalus: >15 mm |
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Aqueductal Stensosis US
http://sonoworld.com/TheFetus/page.aspx?id=3089 |
Hydrocephalus with normal posterior fossa
3rd ventricle dilated Dilatation can be so extreme that normal ventricular anatomy is not discernable Dangling choroid plexus CC thinned and often not visible +/- CSP Head often measures large |
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Top differentials for Aqueductal Stensosis
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Top differentials: holoprosencephaly, hydrancephaly
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Aqueductal stenosis causing obstructive hydrocephalus
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Hindbrain herniation
Almost always with spina bifida |
Arnold Chiari Malformation
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Arnold Chiari Malformation
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Posterior fossa obliterated by hernation of cerebellum
Cerebellum is banana shaped Lemon Head Sign of skull Ventriculomegaly – progresses during pregnancy Head size small to normal Neural Tube Defect of spine http://www.youtube.com/watch?v=oiF4UrVUosE |
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Posterior fossa obliterated by hernation of cerebellum
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Arnold Chiari Malformation
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Arnold Chiari Malformation
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Dandy-Walker Malformation
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Abnormal cerebellum, 4th ventricle, and posterior fossa
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Dandy-Walker Malformation with additional other anomalies
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70-90%
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Ultrasound Findings:
Partial/complete agenesis of cerebellar vermis Abnormal 4th ventricle – communicates with posterior fossa cyst Splayed cerebellum +/- hydrocephalus |
Dandy-Walker Malformation
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Dandy-Walker Malformation
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Used to be known as Dandy Walker Variant
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Vermian Agenesis: partial or complete
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Vermian Agenesis: partial or complete
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Vermis should cover 4th ventricle
Failure of closure = communication of 4th vent with posterior fossa No large posterior fossa cyst |
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Keyhole appearance of 4th vent
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Vermian Agenesis: partial or complete
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Mega Cisterna Magna
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Mega Cisterna Magna
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Cisterna Magna measures >10 mm
Cerebellum normal More often in male fetuses |
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Cranial vault filled with cerebrospinal fluid
Midbrain, cerebellum and basal ganglia remain |
Hydranencephaly
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Hydranencephaly Head size =
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Head size = normal
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Near complete destruction of cerebral hemispheres
Fluid filled skull with residual brainstem present No cerebral hemispheres present Destruction of cerebral hemispheres by occlusion of the internal carotid arteries |
Hydranencephaly
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Other causes of Hydranencephaly
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viral, hemorrhage, toxins, others
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Imaging
Fluid filled cranium with diffuse echos within fluid Falx usually present Normal posterior fossa Normal head size |
Hydranencephaly
http://sonoworld.com/TheFetus/page.aspx?id=116 |
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Hydranencephaly Main differential:
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severe hydrocephalus
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Circle of Willis intact with ___________ and absent in Hydrancephaly
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hydrocephalus
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Hydranencephaly
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Arachnoid Cyst
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CSP fluid collection within layers of arachnoid
Remaining brain sonographically normal |
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Arachnoid Cyst
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Cystic space irregular in shape in cranial midline posterosuperior to third ventricle
Turbulent flow with Doppler Doppler helps distinguish from cysts |
Vein of Galen Aneurysm
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Microcephaly
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head circumference more than 2 standard deviations below mean
IUGR vs abnormality |
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In what time period does HELLP syndrome usually present?
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Presents in 3rd trimester
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What is the best diagnostic clue to identify the HELLP syndrome on ultrasound?
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Intrahepatic or subcapsular fluid collection
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3.What does the acronym HELLP stand for?
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Hemolysis • Elevated Liver enzymes • Low Platelet count
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The most common reason for misdiagnosing Lissencephaly is due to what?
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-Wrong Dates
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What is the best diagnostic clue when suspecting Lissencephaly?
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-Failure to reach normal cortical developmental milestones.
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True or false? In Type 1 Lissencephaly the cortex has a
cobblestone appearance. |
- False
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What does VACTERL association stand for?
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vertebral defects
anal atresia cardiac defects transesophageal fistula renal anomalies limb abnormalities |
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) List 3 VACTERL association sonographic findings
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Polyhydramnios, Hemivertebrae or scoliosis , Limb defects
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True/False VACTERL association disorder is genetic and occurs in individuals with family history of the disorder?
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FALSE
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T/F Porencephaly is a neurological disorder of the CNS characterized by cysts within the spinal cord
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False within the cerebral hemisphere
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What are the types of porencephaly?
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—Developmental porencephaly caused by
- cytomegalovirus - stroke during brain development —Congenital porencephaly autosomal dominant - clotting factors affected |
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T/F Porencephaly is a common condition.
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FALSE
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What can caregivers do to help a baby with Pierre Robin?
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: lay baby on tummy / side, not on back!
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T/F: Palate surgery occurs immediately after birth to prevent feeding problems
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FALSE
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