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Fetal Head Abnormalities - Coggle Diagram

- - - - Brachiocephaly
        
        too round (CI >83) Cephalic index BPD/OFDx100
        
        “Strawberry Skull”
        
        Trisomy 18
      - Dolicocephaly
        
        too flat (CI < 74)
    - - “Lemon Sign”
        
        Frontal bones scalloped
        
        1% of normal fetuses
        
        assoc. with NTD
      - Cloverleaf Skull
        
        Craniosynostosis
        
        Premature fusion of one or more cranial sutures
        
        Isolated vs Syndromal
      - Macrocephaly
        
        well above 90th percentile
        
        Trunk / femur often normal
        
        related to hydrocephalus
      - Microcephaly
        
        well below 10th percentile
        
        Trunk / femur often normal
        
        Etiologies
        
        Consanguinity (blood related marriage)
        
        Toxins
        
        Chromosomal (13, 18)
        
        Craniosynostosis
        
        Microencephaly
        
        ZIKA virus
        
        “Sloping forehead”
        
        2/3 have other brain ABN
        
        Dx hampered by:
        
        Inaccurate dates
        
        IUGR
  - - - MCKD
      - Polydactyly
      - Encephalocele
  - - - Posterior/Lateral Nuchal Cyst
      - Multiple fine linear septations
      - ML septation= nuchal ligament
  - - - Hydranencephaly
        
        Brain was normal –tissue destruction -replaced by fluid
        
        22 -28 weeks
        
        Possible etiologies (bilateral occlusion ICA, TORCH)
        
        US
        
        Cerebral tissue absent
        
        Ventricles expand to fill space
        
        Falx seen
        
        Thalmus–often present
        
        Midbrain/Hind –present
      - Schizencephaly
        
        Caused by disordered neuronal migration
        
        Associated with ACC (absent CSP)
        
        US
        
        Unilateral or bilateral
        
        CSF fills cleft in tissue
        
        Fluid extends from cranial bone to ventricular system
        
        Schizencephaly-Clefts in cerebral hemispheres from inner cranial bones to ventricular system
    - - Holoprosencephaly
        
        Failed cleavage and rotation of the forebrain/prosencephalon
        
        Types (alobar-semilobar-lobar)
        
        Ass/w
        
        Isolated or chromosomal
        
        Diabetes / Alcohol
        
        Trisomy 13
        
        US
        
        Cerebrum (No hemispheric division)
        
        Ventricles (Monoverntricle)
        
        Thalamus (fused)
        
        CSP/ CC (Absent)
        
        Falx (Absent)
        
        Face (Midline facial defects, hypotelorism, proboscis)
        
        Holoprosencephaly–Failure of cleavage and rotation of the prosencephalon. No hemispheric division, monoventricleand ML facial defects
      - Dandy-Walker Continuum
        
        Malformation
        
        Complete agenesis of the cerebellar vermis
        
        US
        
        Absent or hypoplastic vermis
        
        Cerebellum apart
        
        ↑4th ventricle
        
        Balloons into post fossa
        
        Cyst-like appearance
        
        ↑Cisterna Magna
        
        +/-Ventriculomegaly (Hydrocephalus)
        
        Variant
        
        Partial agenisisof the vermis
        
        Normal 4th ventricle
        
        Mega Cisterna Magna
        
        Normal vermis and 4thventricle
        
        Increased Cisterna Magna size >10mm
        
        DDx
        
        Arachnoid cysts
        
        not midline
        
        Brain **normal**
        
        mass effect > ventriculomegaly
        
        Blake’s Pouch Cyst
        
        Avascular cyst in cisterna magna
        
        Vermis Normal
        
        Cisterna Magna Normal
        
        expansion of the 4th ventricle
        
        Cisterna Magna Septa
        
        Variant seen in normal development
        
        Represent the walls of Blake’s Pouch
      - ACC
        
        Partial or complete Agenesis of the Corpus Callosum
        
        Often associated with other abnormalities (CNS, Body, chromosomal)
        
        US
        
        Absent **CSP**-axial
        
        Absent **CC** -sag “Sunray” or “Sunburst” appearance of Gyri and Sulci
        
        Teardrop ventricles (Colpocephaly) Anterior horns widely spaced
        
        MVM
        
        Elevated/Dilated 3rd ventricle
        
        Don't Dx before 18wks
    - - Hydrocephalus
        
        ↑Pressure in ventricles (Obstruction or x absorption)
        
        US
        
        Sever Ventriculomegaly >15mm
        
        Macrocephaly
        
        Hydrocephalus = Obstructive blockage cause ventriculomegalyand macrocephaly
  - - - Choroid Plexus Cysts
      - Isolated (normal)
      - May be ass/w T18
      - should be >= 3mm
      - Number doesn't matter
      - Significant even if they disappear in OB3
      - Cysts vs heterogenous CP - Cysts are discrete (measurable)
    - - Porencephaly
        
        Brain destruction from hemorrhage or infarction
        
        Necrosis of tissue →CSF cyst remains
        
        May communicate with ventricles or subarachnoid spaces
      - Arachnoid Cysts
        
        Often posterior fossa
        
        May compress cerebral aqueduct
        
        Hydrocephalus
    - - aka GlioependymalCysts
      - Often Superior ML
      - no communication with vent system
    - - Intracranial teratoma
      - TORCH (Toxoplasmosis, Cytomegalovirus (CMV)) ? co-existing intra-abdominal calcifications
    - - Most common is teratoma
      - Sono Findings: IC mass, ABN head shape, ventriculomegaly/macrocephaly
    - - –lack of skull bones and protuberant eyes
    - - ML posterior cystic structure with turbulent flow. Cause by AVM