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The first 25 slides, exactly as they appear. The full deck has 106 content slides.
Radiology
Holoprosencephaly
Built from Obstetric Imaging
What’s inside
10 sections · 106 slides
Overview
- What this topic covers
What holoprosencephaly is
A forebrain that stayed whole, and the spectrum that follows
- The idea in one line
- What should happen normally
- The normal instruction, step by step
- The formal definition
- Graded by how much never separated
- The four grades at a glance
- Two more names you will meet
- The mildest end can be entirely normal in daily life
- From ancient myth to prenatal diagnosis
- A few more landmarks
How common it is
Why the embryo, the fetus and the newborn give three different answers
- Why one condition has many prevalence figures
- Counting in embryos
- The gap between those numbers is the message
- Counting at the 11 to 13 week scan
- A study that also chased the missed cases
- What those 30 fetuses showed
- Two studies shaped by who was tested
- What the big registries report
- Reading the registry numbers
Why it happens
Chromosomes, single genes, and the mother's environment acting together
- Rarely one cause acting alone
- Where the fault starts in the embryo
- A narrow window of vulnerability
- How the defect unfolds
- Things in the environment that raise the risk
- The size of the diabetes signal
- How often chromosomes are to blame
- 40-60%
- Reading those chromosome figures
- When single genes are the cause
- The causes on one page
- What else may be found alongside
What the brain looks like
From one undivided cavity to a nearly normal brain with a fused midline
- The severest grade: one single cavity
- One brain cavity with a large dorsal cyst
- What to notice on that image
- Single cavity and choroid plexuses at 13 weeks
- The middle grade: fused in front, split behind
- Semilobar brain seen from above and below
- The milder grades
- A grade-by-grade imaging chart
- Magnetic Resonance Imaging Neuroimaging Features of Holoprosencephaly Types: alobar and semilobar
- Magnetic Resonance Imaging Neuroimaging Features of Holoprosencephaly Types: alobar and semilobar (continued)
- Magnetic Resonance Imaging Neuroimaging Features of Holoprosencephaly Types: lobar and middle interhemispheric variant
- Magnetic Resonance Imaging Neuroimaging Features of Holoprosencephaly Types: lobar and middle interhemispheric variant (continued)
- The published chart of imaging features
- Three lines worth memorising from that chart
What the face looks like
The same midline signal builds the front of the brain and the middle of the face
- Why the face is involved at all
- The range of faces in this condition
- The four classic patterns
- The words behind those four patterns
- A single eye and a proboscis
- A single nostril and a common nasal cavity
- A cleft in the middle of the upper lip
- The face does not always follow the rule
- HPE faces in an anencephalic fetus
- When the jaw is missing too
- How often the jaw is involved
- Absent jaw with a ball-like proboscis
Finding it with ultrasound
From a 9-week embryo to the third trimester: approach, planes and signs
- Ultrasound is the first-line test
- How to scan in the first trimester
- What three-dimensional ultrasound adds
- How early can it be seen
- Inside the earliest reported case
- The earliest scans, in two and three dimensions
- Turning the picture inside out
- Inversion mode showing the brain cavities
- A small head is an early warning
- How to scan later in pregnancy
- What the head itself tells you
- The classic transverse view
- Cortex crossing the midline and undivided thalami
- The view that settles it
- The scan pathway
- The hardest grade to see
- Absent cavum and dysmorphic ventricles
- Coronal views of joined ventricular bodies
- A sign that is specific to lobar disease
- Three-dimensional surface views of the face
- Why surface rendering is worth doing
Where MRI helps
A supplement to ultrasound, and the test of choice for the milder variants
- Where ultrasound runs out of road
- What MRI brings
- Ultrasound and MRI side by side
- How fetal MRI is actually done
- What MRI has taught us
- Lobar disease on magnetic resonance imaging at 24 weeks
- Dorsal cyst and joined sylvian fissures
- What to look for on those two studies
What else it could be
Midline anomalies that mimic the mild end of the spectrum
- Conditions that look alike
Outcome, counselling and care
What families need to be told, before birth and after
- Severity and timing go together
- Survival in numbers
- Before birth: what can be offered
- After birth: the problems to expect
- What the family actually needs
- Two ways of looking at the same condition
- Key points to carry away
- Key points, continued
- Where to read more
- References
- References (continued)
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- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition