3. Congenital CNS Anomalies
o Incidence in longtem studies about 1 %
o Only minimal identified at birth
o Screening Increases The Number Of
Referred Cases For Evaluation Of Suspected
CNS Anomalies.
o The CNS sonographic appearance changes
throughout pregnancy
4. • Embryonic development of the CNS
•in relation to sonographic findings
• Standard Sonographic Examination
•of the CNS
•Learning Objectives
6. And Fuse As The The Fusion Starts In
It Induces The
Overlying Embryonic
Tissue To Thicken And
Ultimately Fold Over
Neural Tube. The Midtrunk Of The
E m b r y o A n d
Subsequently Extends
To The Cranial And
Caudal Ends
Neural Crest
Neural Tube
Ectoderm
At 5th Week The Cells
Destined To Form The
Notochord Infiltrate Into
The Embryonic Disc.
Neural Groove
Neural Plate
8. the end of 8 weeks of gestation. The development of premature ventricular system is seen.
Three orthogonal images and thick slice of three-dimensional reconstructed image (lower right) of normal brain at
8
10. Normal brain development on the mid-sagittal section between 8 and 12 weeks of gestation). Note the remarkable changing of premature brain
appearance.
9
12. 11
The vermis develops superiorly to inferiorly.
Hypoplasia or developmental arrest results in
varying size deficits of the inferior portion, leaving
a relatively square defect that communicates with
the fourth ventricle and separates the lower
cerebellar hemispheres.
14. sagittalaxial
Effect of Gestational age (Posterior Fossa)
sonograms of posterior fossa in 16-week-old fetus
fourth ventricular roof is visualized in both planes (arrow)
13
15. Fourthnamely the (4)
and acavum septi e u h Ve tric the ventri- ventri- its its closest the structures, follow after the l
The normal for but are normal; (b) a however, this same section picture at 20 horns but are normal; (b)
gure 1 Transvaginal scan of a 14-week fetus. (a) Oblique-1 (sagittal) section: the fetus is facing left. The choroid plexus fills the antrum
the
the lateral ventricles. The anterior horns appear prominent, this gestational age;a Frontal-2 (coronal) sonographic through the the anterior horn
ore lateral ventricles.ventriculomegaly horns hydrocephalus this gestational age; however, this same sonographic picture 20 20 weeks o
re is consistent with ventriculomegaly or hydrocephalus
the is lateral consistent withThe horns normal for atat or he The
Higher (see almost axial Three serial,
o Three open axialand (horizontal) views with the the gure2 be ventriclefossa. (a) (a)a This isis(at this gesta
mis appears to to of (b) somewhat higher, sides the wide the the and left of wide (at (at this appear age, to each other op
(c) entity. C, appear
nd Closer of a Each and the timetable. They reach well-known the 16th this ‘norm
gure 2Lower-most Section (horizontal) views through the posterior fossa. (a) This is the lower-most section Still insert). The
rmis2appears serial, almost (arrow) communicates throughfourth posterior through widethe the lower-most sectionnormal) median
erture (foramenbe Magendie); and communicates withrightfourth ventricle through cerebellar hemispheres gestational closer normal) median
erture (foramen of Magendie); (b) somewhat higher, the right and left sides of the cerebellar hemispherescerebellum closer to each othe
ow); (c) higher still, no ‘vermiandefect’’ is seen and
Of The Cerebellar
Communicates With The fourth ventri- its closest anatomic structures, Ventricle cavum septi
duncular cistern (cisterna postmenstrual week,fourth ‘normal’ pellucidi anatomic pericallosal artery, namelythe the well-known
. Later, after narrows 16th postmenstrual week, developmentTo’ developmental pericallosal artery, follow developmen-
en space narrows giving rise tal stage that allows for sonographic imaging until post-
Magendie) rise to the median aperture 14
by those normal
18. 16
Hypoplasia Or Dysplasia Should Not Be
Diagnosed Prior To 18 Weeks, Before Vermian
Development Is Complete.
An Abnormally Steep Scanning Angle May
Mimic A Prominent Cleft Between The
Lower Portions Of The Cerebellar
Hemispheres.
The fetal cerebellum
Pitfalls in diagnosis
53. (< 10 mm is normal). Independent
of gesta7onal age
Mild 10 – 15 mm
Low Risk
Severe > 15 mm
High Risk
mean = 6-‐8
mm
Ventriculomegaly (hydrocephalus)
54. Lee Lateral Ventricle
Aqueduct of Sylvius
4th Ventricle
Right Lateral Ventricle
Foramen of Monro
3rd Ventricle
Cisterna Magna
Pathogenesis: Ventriculomegaly
35
55. •Square Shaped, Interrupts and Fills The Space Between The Frontal Horns
•The CSP: Becomes Visible At 16 Weeks, Obliterate Near Term
Absent CSP
56. •Square Shaped, Interrupts and Fills The Space Between The Frontal Horns
•The CSP: Becomes Visible At 16 Weeks, Obliterate Near Term
Cavum Sep3 Pellucidi
Absent CSP
57. A rare finding usually discovered Postnatally in
children evaluated for developmental delay.
Associated with various brain malformations:
agenesis of the corpus callosum
Holoprosencephaly.
Setpo-‐optic dysplasia.
Secondary to disruptive process: Hydrocephalus,
Chiari II malformation, hydranecephaly.
Absent CSP
Sunday, July 28, 13
59. Originally published in Ultrasound Obstet Gynecol 2007; 30: 233–245
Normal corpus callosum
3v
3v Par3al agenesis
3v
74
Agenesis of the
corpus callosum
Absent corpus callosum
60. Only The Rostrum (1), Genu (2) And Body (3) Are Visible; The Splenium Is
Missing. The Corpus Callosum Is Short Posteriorly And Does Not Seem To Overlay
The Quadrigeminal Plate
21-‐week Fetus With Par=al Agenesis Of The Corpus Callosum
61. Outcome of fetal ACC
Varies between completely asymptoma3c
appearance and severe neurologic problems
50 – 100 % of isolated cases will have normal
neurological development at 3-‐11 years but Poor
prognosis with associated anomalies
Progressive decline in intellect over the years
Most need special educa3on
Long-‐term follow-‐up of children with prenatally diagnosed agenesis of corpus callosum (ACC)
J. H. Stupin et al, USOG, 32, 2008
74. Lateral Ventricle
Third
Ventricle
Cerebral Aqueduct
Choriod Plexus
foramina of Luschka and
Magendie leads to dilatation
of the fourth ventricle and
and elevation of the vermis
awayfromthebrainstem.
Fourth Ventricle
Pathogenesis: Blake’s Pouch Cyst
Nonfenestration of the
There is no communication between the
cyst and the subarachnoid space
47
75. Lateral Ventricle
Third
Ventricle
Cerebral Aqueduct
Choriod Plexus
foramina of Luschka and
Magendie leads to dilatation
of the fourth ventricle and
and elevation of the vermis
awayfromthebrainstem.
Fourth Ventricle
Pathogenesis: Blake’s Pouch Cyst
Nonfenestration of the
There is no communication between the
cyst and the subarachnoid space
47
76. ✦Complete Or Partially Agenesis Of The Cerebellar
Dandy-Walker Malformation
48
ASpectrumOfAnomaliesOfThePosteriorFossa.
•Dandy-WalkerMalformation:
✦IncreaseOfThePosteriorFossa,
Vermis,
✦ATentoriumElevation
•VariantOfDandy-Walker:
✦Hypoplasia Of The Cerebellar Vermis In Different
Degrees With Or Without Increase Of The Posterior
Fossa.
77. ctions
Dandy-Walker Malformation
Elevated tentorium and
high position of the
torcula
Small, rotated, raised,
or absent vermis
Cystic dilation of the
fourth ventricle
communicating with a
posterior fossa fluid
space
49
79. Figure Torcular Is Found InANormalandy–Walker Malformation position the torcular igure 2
on of the tentorium cerebelli. Inthe direction by theultrasound the direction tentorium cerebelli. In (a)The Torcular Is Displaced Higher
orcular found normal position, about the same level as
he site of insertion of the neck muscles on the posterior skull; thisite of insertion of the neck muscles on the posterior skull; thisSkull
a Blake a pouch cyst. In (b) the torcular is displaced higBlake’s
51
The
AsThe found Insertion normala OfThe
Neck Muscles
isSunday, July 28, 13 ’s pouch cyst. In (b) the torcular is displaced higher th
80. •
•
•
•
Are Benign, Noncommunicating Fluid
Collections Within Arachnoid
Membranes.
Location: Intracranially And In The
SpinalCanal.
Order Of Frequency Are The Sylvian
Fissure Or Temporal Fossa, Posterior
Fossa, Over The Cerebral Convexity,
AndMidlineSupratentorial,
Most Appear Stable And Require No
Surgical Treatment. Occasionally They
Arachnoid Cysts
Interfere With CSF Circulation And
RequireDecompression.
81. The Differential Diagnosis
Depends On The Location.
In The Posterior Fossa:
DandyWalker Malformation, Inferior Vermian
Hypoplasia, Mega–cisterna Magna, And Blake’s Pouch
Cysts.
Supratentorial Cysts:
Cavum Veli Interpositi, Aneurysm Of Vein Of Galen,
Hemorrhage, And Cystic Tumors.
53
82. 54
Prenatal diagnosis and outcome of fetal posterior
fossa fluid collections
G. GANDOLFI COLLEONI et al,
Ultrasound Obstet Gynecol 2012; 39: 625–631
83. Vermian Hypoplasia
N=17
55
Blake’s Pouch Cyst
N = 32
Arachnoid Cyst
N=1
Megacisterna Magna
N = 27
Cerebellar Hypoplasia
N=2
Dandy – Walker Malformation
N=26
105
Fetuses
Sonographic
diagnoses
were accurate
in 88%
84. ✦Isolated Cases Of Blake’s Pouch Cyst And
Megacisterna Magna Have An Excellent Prognosis,
With A High Probability Of Intrauterine Resolution
And Normal Intellectual Development In Almost All
Cases.
✦Dandy – Walker Malformation And Vermian
Hypoplasia, Even When They Appear Isolated
Antenatally, Are Associated With An Abnormal
OutcomeInHalfOfCases.
56
85. 57
•Black’s Pouch Cyst, DW Malformatio
Mega-‐Cisterna Magna Can give Si
Sonographic features.
•However the prognosis is greatly vari
•Careful Neurosonographic assessment us
D or Fetal MRI is often Needed
Conclusion
Sunday, July 28, 13
86. Originally published in Ultrasound Obstet Gynecol 2007; 30: 233–245
Brain stem Cerebellar vermis
Angled Insona3on of Posterior Fossa
Visualize brain Stem
4v
65
87. Originally published in Ultrasound Obstet Gynecol 2007; 30: 233–245
4v
hemisphere
hemisphere
hemisphere
vermis
hemisphere
tentorium
4v
tentorium
vermis
vermian fissures
88. Normal Posterior Fossa At Midgesta=on
SagiGal viewAxial view
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
89. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cavum Sep3
Pellucidi
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
90. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cavum Sep3
Pellucidi
Cerebellar vermis
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
91. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cisterna Magna
Cavum Sep3
Pellucidi
Cerebellar vermis
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
92. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cisterna Magna
Cavum Sep3
Pellucidi
Cerebellar vermis
Tentorium
Cisterna Magna
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
Sunday, July 28, 13
93. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cisterna Magna
Cavum Sep3
Pellucidi
Cerebellar vermis
Tentorium
Cisterna Magna
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
94. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cisterna Magna
Cavum Sep3
Pellucidi
Cerebellar vermis
Tentorium
Cisterna Magna
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
95. SagiGal viewAxial view
Normal Posterior Fossa At Midgesta=on
Cisterna Magna
Cavum Sep3
Pellucidi
Cerebellar vermis
Tentorium
Cisterna Magna
Prenatal diagnosis and outcome of fetal posterior fossa fluid Collec=ons
Gandolfi Colleoni et al., UOG 20
97. Blake’s pouch cyst Megacisterna magna D-‐W
Findings Upward rotation of an intact vermis
with normal torcular
Cisterna magna >10mm with intact
and normally positioned cerebellum
Upward rotation of the v
(normal or hypoplastic) w
elevated torcular
Categoriza3on of posterior fossa fluid collec3ons (1)
SagiGal
Axial
99. Measurement of brainstem–vermis (BV) and 80Figure 1 The Vermis: Shape, Size, Fissures brainstem–tento
Cavum Sep3
Pellucidi
The Tentorium: Level
case after acquisition of an ultrasound volume starting from an axi
101. Blake’s Pouch
Cyst
Cerebellar Vermis
Hypoplasi
Dandy–Walker
Malformation.
TheAngles Has The Widest Measurement In DA
Malformation
82
and (BT) (BT) (a) A (a) A view the of the fetal brain is
after of of volume starting from an an axial and the anatomic are are
1 Measurement of brainstem–vermis (BV) brainstem–tentoriumangles. angles.median median ofviewfetal brain is obtain
e acquisitionan ultrasound volume starting from axial view)view) the and main anatomic landmarks landmarks ide
angentially tangentially dorsal dorsal aspect aspect brain brain stema second second is drawn tangentially tangentially ventra
vermis; the interposed angle (1) is the BV angle; the BT angle (2) is measured between the first line and a third line tangential to the tent
to to the aspect of of the stem and and a line line is drawn to the to the ventral of the of the drawn
Measurement of brainstem–vermis (BV) angle (1) and brainstem–tentorium (BT) angle (2) in fetuses with: (a) Blake’s pouch cys
Figure 2
102. 84
Fetal posterior fossa fluid collections associated
With upward rotation of the cerebellar verm is ranged
from benign asymptomatic conditions to severe
abnormalities associated with neurological
impairment.
The most frequent of these anomalies, Blake’s
pouch cyst, vermian hypoplasia and Dandy–
Walker malformation, have a similar sonographic
Appearance but a very different prognosis
Conclusion
106. Prac3cal Approach to the DD of Posterior Fossa
Cyst and Cys3c like Lesions
1. Is the Vermis Present?Is the Vermis intact?
107. Prac3cal Approach to the DD of Posterior Fossa
Cyst and Cys3c like Lesions
1. Is the Vermis Present?Is the Vermis intact?
2. Is the Toruclar in a normal posi3on (tentorial
Cerebelli)?
108. Prac3cal Approach to the DD of Posterior Fossa
Cyst and Cys3c like Lesions
1. Is the Vermis Present?Is the Vermis intact?
2. Is the Toruclar in a normal posi3on (tentorial
Cerebelli)?
3. What is the shape of the cerebellar clee?
109. Prac3cal Approach to the DD of Posterior Fossa
Cyst and Cys3c like Lesions
1. Is the Vermis Present?Is the Vermis intact?
2. Is the Toruclar in a normal posi3on (tentorial
Cerebelli)?
3. What is the shape of the cerebellar clee?
4. Brainstem–vermis (BV)Angle And Brainstem–
tentorium (BT)Angle
110. Originally published in Ultrasound Obstet Gynecol 2007; 30: 233–245
Normal Megacisterna magna
Vermian hypoplasia
Blake’s pouch cyst
tentorium
Dandy-‐Walker malforma3on
89
114. 91
✦examina3on of the Fetal CNS should be follow a
Standard Protocol
✦Examina3on should include at least three axial
planes.
115. 91
✦examina3on of the Fetal CNS should be follow a
Standard Protocol
✦Examina3on should include at least three axial
planes.
✦In Each plane the defined landmarks should
should be reported as normal or suspicious
116. 91
✦examina3on of the Fetal CNS should be follow a
Standard Protocol
✦Examina3on should include at least three axial
planes.
✦In Each plane the defined landmarks should
should be reported as normal or suspicious
✦In the presence of possible abnormali3es pa3ent
should be referred for detailed neuorsonogram
which include mutli-‐planner 3 D Sanning.
117. 91
✦examina3on of the Fetal CNS should be follow a
Standard Protocol
✦Examina3on should include at least three axial
planes.
✦In Each plane the defined landmarks should
should be reported as normal or suspicious
✦In the presence of possible abnormali3es pa3ent
should be referred for detailed neuorsonogram
which include mutli-‐planner 3 D Sanning.
✦3 D scanning with mul3planner analysis offers
comparable analysis to fetal MRI