Module 5: Fetal Neuo Pathology Flashcards
Where is CSF produced?
Choroid plexus
What is the choroid plexus?
A collection of cells located in the ventricles that produce CSF
Where in the ventricles is the choroid plexus located?
- Floor of lateral ventricles
- Roof of 3rd ventricle
- Posterior wall of 4th ventricle
Trace the flow of CSF from the lateral ventricles
Lateral ventricles through interventricular foramen to 3rd ventricle through cerebral aqueduct to the 4th ventricle and then exits medially to the magendi and laterally to the two luschka and from there it flows into the subarachnoid space and circulates with the spine and brain respectively.
What is another name for the interventricular foraman?
Foramen of Monro
What is another name for the cerebral aqueduct?
The aqueduct of Sylvius
What structures does CSF flow through to circulate the brain and spine?
Spine = Magendi (medial)
Brain = Two Luschka (lateral sides)
Where is the 4th ventricle located?
Inferiorly to cerebellum
What is the most common cranial anomaly?
Hydrocephalus
What is hydrocephalus?
Increase in CSF causing enlarged ventricles
What is “true” hydrocephalus?
Hydrocephalus caused by a CSF obstruction
What is ventriculomegaly?
Enlarged ventricles resulting from brain atrophy (small brain = more room for ventricles to fill up).
Not “true” hydrocephalus
What are the causes of “true” hydrocephalus?
- Neural Tube Defect (NTD)
- Aqueductal stenosis
- Dandy Walker Malformation
What is an aqueduct stenosis?
When CSF cannot flow from the 3rd to 4th ventricle
What ventricles are enlarged in the presence of an aqueduct stenosis?
The lateral and 3rd are enlarged
The 4th is normal
What are the causes of extraventricular obstruction causing hydrocephalus? (3)
- Spina Bifida - flow obstructed in spine, backs up all ventricles
- Excess CSF - excessive secretion from a choroid plexus
- Dandy Walker Malformation
How do you assess the ventricular size?
Measure atrial diameter, size doesn’t change much from 15-35 weeks
What is the normal measurement and upper limit of the ventricles?
Normal = 7mm
Upper limit = 10 mm
How does the Choroid appear in a normal ventricle?
Hyperechoic, less than 3 mm from the medial ventricle wall and the choroid plexus should not appear to “dangle” in the atria of the ventricle
What does the position of the Choroid Plexus depend on?
Gravity
If hydrocephalus is present, how likely is an additional anomaly?
70-80%
What structures are seen in the posterior fossa view?
- Cisterna Magna
2. Cerebellum
How does an obliterated cisterna magna appear on US?
Cerebellum right up agains posterior skull
What is the banana sign?
Deformed cerebellum shaped like a banana due to downward displacement through the foramen magna from spina bifida with Arnold Chiari Malformation