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Radiology
Ventriculomegaly
Built from Obstetric Imaging
What’s inside
14 sections · 109 slides
Overview
- What this deck covers
What the finding is
A sign on the scan, not a diagnosis
- Start with the space, not the word
- The measurement that names the finding
- A sign, not a disease
- Four things that decide the outlook
- Why paediatricians say hydrocephalus and we do not
- Where the 10 mm cut-off comes from
- Grading the width
- Two grading systems exist
- Mild isolated ventriculomegaly at 22 weeks
- Severe ventriculomegaly at 20 weeks
How often it is seen
Wide reported ranges, and why they disagree
- 1:50 - 1:1600
- Why the incidence figures disagree so much
Why ventricles enlarge
Blocked flow, poor absorption, or a brain built differently
- Fluid in, fluid out
- The route cerebrospinal fluid takes
- When the pipe is blocked
- The level of the block sets the pattern
- Blocks built into the ventricular system
- Blocks that develop during the pregnancy
- When nothing is blocked
- Three ways ventricles end up wide
- Wide ventricles without any blockage
- Wide ventricles from tissue that was destroyed
- Irregular walls and echogenic debris after a destructive insult
- What to notice in that clastic picture
Looking properly
Targeted neurosonography and a systematic sweep
- Apparently isolated is not the end of the scan
- Why the transvaginal probe is preferred
- Getting a breech fetus into position
- A structured hunt for the cause
- The framework, first half
- The framework, second half
- Ask about the clinical setting too
- The order to scan in
- The anterior complex
- Do not mistake the fornix for the cavum
- Third ventricle and the structures behind it
- Assessing the fetal ventricular system in three planes
- Axial view: anterior complex and the measuring landmark
- Reading that axial panel
- Coronal view of the anterior complex
- Reading that coronal panel
- The coronal planes, front to back
Measuring the atrium
A number worth trusting has a fixed technique
- When the measurement is taken
- Caliper technique
- Standard measurement of ventricular width on the axial plane
- What the red line is showing
- Measuring on the coronal plane instead
Is it really isolated?
A diagnosis reached only by ruling things out
- Isolated is a diagnosis of exclusion
- Follow the whole fluid pathway
- Look at the folds of the cortex
- Why the cortex can look fine and still be wrong
- Signs of bleeding or ischaemia
- Signs of infection and of heterotopia
- How often something else is found
- How open spina bifida makes the ventricles enlarge
- Moderate ventriculomegaly with open spina bifida
- Normal midline anatomy compared with absent corpus callosum
- How to work through that six-panel figure
- Mild ventriculomegaly with a missing cavum septi pellucidi
The differential list
What must be excluded before saying isolated
- Use the list as a checklist
- Associated Anomalies in Ventriculomegaly and Differential Diagnoses of Isolated Ventriculomegaly
- Associated Anomalies in Ventriculomegaly and Differential Diagnoses of Isolated Ventriculomegaly (continued)
- The differential list as printed in the book
The brain keeps developing
Normal today does not mean normal in three months
- Normal for now, not normal forever
- Which anomalies appear late
- How much is still missed
- Ventricle size as a prognostic marker elsewhere
Where MRI fits
A complement to ultrasound, not a replacement
- Ultrasound first, MRI to add detail
- What MRI is best at seeing
- 5.4%
- Reading those two numbers
- When to book the MRI
Presentation and work-up
What isolated means, and what to order
- What isolated formally means
- Why isolated is a fragile label
- When it turns up
- What to order once VM is found
- The three factors that matter most
- Newborn signs of raised fluid pressure
- Severity and stability both count
What happens to these children
The outcome data, and why they are so variable
- Mild isolated ventriculomegaly at birth
- Why the published numbers disagree
- The word neurodevelopmental is doing too much work
- Test too early or too late and you get a different answer
- What counts as an abnormal score
- A study that changed its own answer
- The same children at school age
- Delay is not the same as disability
- 8%
- One-sided and asymmetric ventricles
- Outcome after severe ventriculomegaly
- What the literature still cannot tell us
Management
Before birth and after
- Screen the mother for infection
- Chromosomes
- Platelet antibodies: not routine
- Follow-up scans
- In utero shunting was tried and abandoned
- Planning the birth
- The first steps after birth
- Tests to complete after birth
Take it away
What to remember and what to say
- What the referring physician needs to know
- Key points, part one
- Key points, part two
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition