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Radiology
Cerebellar Anomalies
Built from Obstetric Imaging
What’s inside
11 sections · 65 slides
Overview
- What this topic covers
How the fetal cerebellum forms
From one fluid vesicle at 7 weeks to a closed vermis by about 20 weeks
- How the fetal cerebellum forms
- The first structure to appear
- The vermis fills in last
- Why late development trips people up
What to measure
Cerebellar width and the width of the fluid pocket behind it
- Two numbers do most of the work
- Where the calipers go
- What to notice in the next picture
- Normal biometry beside a markedly small cerebellum
- What a too-small cerebellum means
- Reading the cisterna magna width
- How to measure the cisterna magna
The stepwise examination
Five named landmarks, in order, instead of an overall impression
- Five steps through the posterior fossa
- Why a checklist beats a glance
- Judging the vermis is the hard part
- What a complete vermis check includes
- What to notice in the next picture
- The normal vermis in three planes
- Vermian fissures on the midline view
- The pons, step five
When the cerebellum is too small
Hypoplasia, rhombencephalosynapsis and growth restriction
- Cerebellar hypoplasia: what it is
- Cerebellar hypoplasia: when it is found
- What to do with a borderline small cerebellum
- What to notice in the next picture
- Fused hemispheres beside a simply small cerebellum
- Rhombencephalosynapsis: what it is
- How the diagnosis is confirmed
- The company rhombencephalosynapsis keeps
- Growth restriction and the small cerebellum
When the two halves do not match
Cerebellar hemispheric asymmetry is usually the scar of an old injury
- Cerebellar hemispheric asymmetry
- Other causes of a one-sided small cerebellum
- How a cerebellar bleed changes over time
- Cerebellar asymmetry after bleeding
- Outlook after cerebellar asymmetry
When the cisterna magna is too small
An obliterated fluid pocket sends you straight to the spine
- A cisterna magna under 2 mm
- Finding the spinal defect
When the cisterna magna is too large
One question splits the differential: is the vermis normal?
- Over 10 mm: what to do next
- Sorting out a large cisterna magna
- Mega cisterna magna
- Retrocerebellar arachnoid cyst
- Blake pouch cyst
Dandy-Walker malformation
A cystic posterior fossa, an abnormal vermis and a lifted tentorium
- Dandy-Walker malformation: the definition
- The signs you must actually show
- What to notice in the next picture
- A large fourth ventricle opening into a large cisterna magna
- The elevated tentorium, enlarged
- Dandy-Walker malformation: judging the outlook
The vermis: hypoplasia, agenesis and traps
A confused vocabulary, and a false-negative that catches everyone
- A confusing set of names
- Isolated vermian hypoplasia
- Vermian agenesis and its trap
- Three ways to avoid the trap
- Molar tooth-related syndromes
Signs, differentials and what to say
Pulling the findings together into a report and a conversation
- How these fetuses present
- Classic signs to recognise
- Differential for a large cisterna magna
- Prenatal management
- After birth
- What the referring physician needs to know
- Key points
- Suggested readings
- References
- References (continued)
- References (continued)
- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition