Normal Pressure Hydrocephalus

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Normal Pressure Hydrocephalus

• Jalal Jalal Shokouhi M.D.
• President of Iranian society of radiology
• Jaam e jam medical imaging center
• Koorosh medical imaging center

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Ventricular system
CSF production 0.2-0.35 ml/min total volume 120
ml
lateral ventricle ? foramen of Monro? third
ventricle,? cerebral aqueduct ?fourth ventricle
?foramina of Luschka and Magendie? subarachnoid
space ? arachnoid granulations? dural sinus ?
venous drainage.
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Hydrocephalus

• A disturbance of formation, flow, or absorption
  of CSF ? an increase in volume in CNS
• Communicating / non Communicating
• (full communication between ventricles and
  subarachnoid space)
• Cerebral atrophy and focal destructive lesions?
  vacant space filled with CSF
• (hydrocephalus ex vacuo)

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Normal pressure hydrocephalus (NPH)

• First described in 1965 by Hakim and Adams
• Clinical triad of symtoms
• - gait disturbance
• - dementia
• - incontinence
• Image communicating hydrocephalus
• Potenially reversible by shunting symptoms lt2y

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A sagittal T1-weighted image of a patient with
NPH, showing the flow quantification section
positions the arterial section (A), the aqueduct
section (B), and the venous section (C).
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Etiology of NPH

• Idiopathic 50,elderly gt 60 y, worse response
  to shunting (3050)
• Secondary 50, younger age, better response to
  shunting (5070)
• - head injury
• - subarachnoid haemorrhage
• - meningitis
• - neurosurgery

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Etiology of idiopathic NPH

• Combination of mechanisms gt a single cause
• Decreased CSF resorption at arachnoidal villi or
  granulations ? increases transmantle pressure
  (CSF pressure within ventricles gt in subarachnoid
  space) ? ventricular enlargement
• Short-lasting CSF pulsations (B waves)
  periodically apply pressure to the ventricular
  walls and have a water-hammer effect that
  enlarges the ventricles

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Anatomy

• Enlarged third ventricle
• Dilation of the occipital, frontal, and temporal
  horns of the lateral ventricles.
• Presumably, the periventricular white matter is
  stretched and dysfunctional as a result of
  inadequate perfusion, without actually being
  infarcted

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Unexpected manifestration

• Papilledema
• Seizure
• headache

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Brain Imaging

• MRI or CT must be performed to assess ventricular
  size and to rule out ventricular obstruction.
• Either CT or MRI can document noncommunicating
  ventriculomegaly sufficient to satisfy the brain
  imaging requirements for routine diagnosis of
  INPH.

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• CT scan or MRI
• - Ventricular enlargement out of
  proportion to sulcal atrophy
• - Prominent periventricular hyperintensity
  (transependymal flow of CSF)
• - Prominent flow void in the aqueduct and third
  ventricle, the so-called jet sign, (presents as
  a dark aqueduct and third ventricle on a
  T2-weighted image where remainder of CSF is
  bright)
• Thinning and elevation of corpus callosum on
  sagittal images
• Rounding of frontal horns
• May have hyponatremia (SIADH)

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• a rounded frontal horn

The arrow points to transependymal flow.
T2-weighted MRI showing dilatation of ventricles
out of proportion to sulcal atrophy
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Measurement of CSF-OP

• Normal CSF-OP averages 122 34mmH2O
• INPH, CSF-OP averages 150 45 mmH2O
• (60-240 mm H2O)
• Transient high pressures (B waves) are
  detectable during prolonged intraventricular
  monitoring in adults with symptomatic INPH
• OP is elevated gt 18 mm Hg indicate secondary or
  noncommunicating hydrocephalus than INPH

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• Patients with a good response to the above
  procedure
• are candidates for ventriculoperitoneal or
• ventriculoatrial shunting.
• Best results - patients who have no adverse risk
  factors -responded favorably to
  a large-volume LP
  -definite evidence of dementia and ataxia,
  - CT scan or MRI evidence of chronic
  hydrocephalus,
• - a normal CSF at lumbar
  puncture.
• Some evidence indicates that patients with gait
  disturbance, mild or no incontinence, and mild
  dementia fare best among shunt surgery patients.

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• Thank you