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Andrea Rossi, MDNeuroradiology Unit
IRCCS Istituto Giannina Gaslini, Genoa/Italy
Imaging in hydrocephalus: Diagnosis, monitoring and
complications
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
The Ventricular System
Contains approx. 17% of total CSF (25.5: 150 mL)
Ventricular Outlets
CisternsCistern of great vein or
transverse cistern
Cisterna ambiens or
cistern of the
quadrigeminal plate
Cisterna
vermis
Cisterna magna or
cerebellomedullary
cistern
Perimedullary Cistern
Prepontine Cistern
Interpeduncolar Cistern
Chiasmatic CisternBasal
cistern
Cistern of the
lamina
terminalis
Interhemispheric
Cistern
Foramina of Monro
Cerebral aqueduct (of Sylvius)
3
4
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of adult and pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
Mantovani G et al, 2018
THE CSF BULK FLOW THEORY© omicsonline.org
H.W. Cushing, 1869-1939
OBSTRUCTIVE
HYDROCEPHALUS
obstruction to the CSF flow inside the
ventricular system
The ventricles dilate proximal to an
intraventricular obstruction to the bulk flow
of CSF
Communicating hydrocephalus is characterized
by enlargement of the ventricles, mainly the
lateral and third ventricle, and a narrow
subarachnoid space
COMMUNICATING
HYDROCEPHALUS
obstruction to the CSF flow outside the
ventricular system
This anatomy cannot be explained by an
obstruction to the bulk flow at the arachnoid
granulations
Matsumae et al, 2016
CSFnoncirculation
model
• Fluids movements and exchanges are free among different intracranial
compartments
• Hydrostatic and osmotic forces are the main determinants
• Dynamic equilibrium among parenchyma, interstitial space, subarachnoid
space, vascular compartment, and ventricles
• Hydrocephalus is not an imbalance between CSF production and resorption, but an imbalance between interstitial fluid (decreased) and ventricular fluid (increased)
• Benign intracranial hypertension (pseudotumor cerebri) is an opposite imbalance (increased interstitial fluid and decreased ventricular fluid)
• Hydrocephalus caused by tumoral aqueduct obstruction could be due to an increased osmolarity
• Post-hemorrhagic hydrocephalus could be caused by an obstruction of interstitial fluid and/or a hyperosmolar intraventricular/subarachnoidfluid
Mantovani et al, 2018
…. The consequences ….
S D
• The algorithms used to obtain flow estimate in cine-MRI are based on the
hypothesis that there is net craniocaudal CSF flow through the aqueduct,
whose diameter is assumed to be constant during a cardiac cycle
• The evaluation of flow void is highly subjective, also depending on
acquisition parameters used Mantovani G, 2018
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
Agarwal et al, 2016
Agarwal et al, 2016
Agarwal et al, 2016
CONGENITAL HYDROCEPHALUSthe condition is present at birth, caused by a complex interaction of
genetic and environmental factors during fetal development.
Congenital hydrocephalus is now often diagnosed before birth
through routine ultrasound and MRI
ACQUIRED HYDROCEPHALUSdevelops after birth as a result of neurological conditions such as
head trauma, brain tumor, cyst, intraventricular hemorrhage or
infection of the central nervous system
CONGENITAL vs ACQUIRED
• Monoventricular
• (Biventricular)
• Triventricular
• Tetraventricular
POINT OF OBSTRUCTION
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
CLINICAL SCENARIOS
Clinical features of hydrocephalus are
influenced by the following:
• Patient's age
• Cause
• Location of obstruction
• Duration
• Rapidity of onset
NEONATES AND INFANTS
• A full or bulging fontanel
• Seizures
• Bulging eyes and persistent
downward gaze (“setting-sun” eye
phenomenon)
• Increasing head circumference!
• Prominent scalp veins
• Increased irritability
• High-pitched cry
• Poor feeding
• Sleepiness or less alert than
usual
• Developmental delays
• Projectile vomiting
• Headaches (initially in the morning)
• Vomiting (more significant in the morning)
• Blurred vision (consequence of
papilledema and later of optic atrophy)
• Double vision (unilateral or bilateral sixth
nerve palsy)
CHILDREN
• Stunted growth and sexual maturation from third ventricle
dilatation (obesity, precocious puberty or delayed onset of puberty)
• Difficulty in walking secondary to spasticity (lower limbs+++
due to stretching of periventricular pyramidal tract)
• Drowsiness
• Slowing of mental capacity
• Neck pain suggesting tonsillar herniation
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
Dilatation of
Temporal Horns
Dilatation of anterior
III ventricle
Overt signs: ventricular dilatation, periventricular edema,
reduced subarachnoid spaces
Optic disc protrusion, flattening posterior sclera
Disappearance of aqueductal flow-void
DDx “ex vacuo”
WM thinning
Enlarged subarachnoid spaces
Disproportionate body vs temporal horn
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
Case # 1
Malformative aqueductal
stenosis
8 d
T2/DRIVE
8 d 15 m
Case # 2
Low-grade tectal glioma
5 mT2
T1 T1+C
T2/DRIVE
5 mT2
T1
8 m
Malformative stenosis:
Inferior third
Neoplastic stenosis:
Superior third
Case # 3aPost-hemorrhagic hydrocephalus
T2T1 T2/DRIVE1 d
T2T1 T2/DRIVE1 d
1 y
Case # 3bPost-hemorrhagic hydrocephalus
Superficial siderosis
Case # 4a
IV ventricle outlet obstruction
14 m
* *
14 m 27 m
* *
Case # 4bIV ventricle outlet obstruction
(Post-hemorrhagic)
CT Ventriculography
Case # 4c
IV ventricle outlet obstruction
(developmental)
4 v
130 day fetus
Blake’spouch
4 v
BP
Normal 25 W
Blake’s Pouch Cyst
Mega Cisterna Magna Arachnoid Cyst
Dandy-Walker Malformation
Case # 5a
Chiari I anomaly
Chiari I
Case # 5b
Chiari II malformation
Chiari II
Case # 5a
Single ventricle dilatation →
obstruction Monro
Case # 5b
Single ventricle dilatation →
obstruction Monro
(TSC, SEGA)
3Y 2M 4Y 4M 4Y 8M 4Y 11M
(3m rapamycin th)
Case # 6a
Ventricular compression
3Y ependymoma
Case # 6b
Ventricular compression
IV ventricular obstruction
4Y pilocytic astrocytoma
Case # 7Choroid plexus papilloma
normal choroid plexus papilloma
CSF overproduction
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Monitoring
8. Imaging of treated hydrocephalus
Pros:
Reduced exposure to ionizing radiation
Cons:
• Increased costs (?)
• Suboptimal catheter visualization
• Risk of valve malfunction after repeated
exposure to high magnetic fields
• Need for reprogramming with many
types of adjustable valves
MONITORING: MRI (rapid) vs CT
Ssh/TSE
9 sec
Outline
1. Anatomy
2. CSF Flow Dynamics
3. Classification schemes
4. Clinical scenarios
5. Basic imaging signs
6. Causes of pediatric hydrocephalus
7. Fetal hydrocephalus
8. Imaging of treated hydrocephalus
Hydrocephalus: treatments
SHUNTING THIRD VENTRICULOSTOMY
Mammillary bodies
Tuber
Infundibular recess
The Liliequist membrane:
arachnoid membrane separating the chiasmatic
and interpeduncular cisterns
The tip of the basilar artery
SUBDURAL COLLECTIONS
Too rapid drainage
SLIT VENTRICLE SYNDROME
• The absence of CSF within the ventricles combined with a
growing brain leads to situation in which "the brain is too big for
the skull"
• The intracranial pressure can be very high despite small
ventricular size
• Headache, lethargy, nausea, vomiting
CHRONIC CSF OVERDRAINAGE
NOT CHIARI 1, PLEASE!
Conclusions
• The radiologist can help to identify the
causes and surgical candidates and to
follow them up after treatment
• MRI must be technically flawless and
include hi-res T2WI and CSF flow studies
• Fast MRI protocols can safely replace CT
for ventricular size monitoring