200
L. Geregele et al.
approach 20%, a preimplanted Ommaya reservoir 38%, shunt prechamber 40%, or
open EVD 2%).
PC-MRI material was derived from the database at the Department of Image
Processing, Amiens University Hospital, France, containing more than 500 volunteers and patients suffering from hydrocephalus, syringomyelia, and other CSF
circulatory defects.
Although illustrative material is derived from two centres, similar results are
reported from many other hospitals worldwide, known as a centre of excellence
in studies on hydrocephalus and CSF disorders [4, 10, 25, 34–36, 38, 46, 64, 77,
83, 84].
8.10.1 Differentiation Between Brain Atrophy and Normal
Pressure Hydrocephalus
CSF dynamics in NPH is characterised by a normal baseline pressure
(ICP < 18 mmHg). The resistance to CSF outflow is increased (>13 [mmHg/
(mL/min)]). B waves recorded during infusion are regular. Pulse amplitude is well
correlated with mean ICP. Compensatory reserve at baseline is usually good (RAP
index below 0.6), and usually elastance coefficient slightly increased (E > 0.2 mL −1 )
(see Fig. 8.16).
Patients suffering predominantly from brain atrophy have normal CSF circulation. Typically, opening pressure, resistance to CSF outflow, and pulse amplitude
are low (ICP < 12 mmHg, R CSF < 12 mmHg/(mL/min), amplitude <2 mmHg). The
compensatory reserve at baseline is good (RAP < 0.5), reflecting low elasticity of the
atrophic brain (E < 0.2 mL −1 ). Vasogenic waves are rather limited during recording.
The mean ICP increases smoothly during the infusion and decreases in a similar
fashion following infusion, comparable to the inflation and deflation of a balloon –
Fig. 8.17.
8.10.2 Noncommunicating and Acute Communicating
Hydrocephalus
Lumbar infusion is not recommended in noncommunicating hydrocephalus because
of the risk of brain herniation in the event of uncontrolled CSF leak. However,
this type of hydrocephalus may not always be easy to detect by the brain scan.
In those few instances of noncommunicating hydrocephalus where lumbar infusion
is performed, the resistance to CSF outflow is normal because the lumbar infusion
is not able to detect the proximal narrowing in CSF circulatory pathways. Paradoxically elasticity is relatively low (E < 0.20 mL −1 ). In acute hydrocephalus,
L. Geregele et al.
approach 20%, a preimplanted Ommaya reservoir 38%, shunt prechamber 40%, or
open EVD 2%).
PC-MRI material was derived from the database at the Department of Image
Processing, Amiens University Hospital, France, containing more than 500 volunteers and patients suffering from hydrocephalus, syringomyelia, and other CSF
circulatory defects.
Although illustrative material is derived from two centres, similar results are
reported from many other hospitals worldwide, known as a centre of excellence
in studies on hydrocephalus and CSF disorders [4, 10, 25, 34–36, 38, 46, 64, 77,
83, 84].
8.10.1 Differentiation Between Brain Atrophy and Normal
Pressure Hydrocephalus
CSF dynamics in NPH is characterised by a normal baseline pressure
(ICP < 18 mmHg). The resistance to CSF outflow is increased (>13 [mmHg/
(mL/min)]). B waves recorded during infusion are regular. Pulse amplitude is well
correlated with mean ICP. Compensatory reserve at baseline is usually good (RAP
index below 0.6), and usually elastance coefficient slightly increased (E > 0.2 mL −1 )
(see Fig. 8.16).
Patients suffering predominantly from brain atrophy have normal CSF circulation. Typically, opening pressure, resistance to CSF outflow, and pulse amplitude
are low (ICP < 12 mmHg, R CSF < 12 mmHg/(mL/min), amplitude <2 mmHg). The
compensatory reserve at baseline is good (RAP < 0.5), reflecting low elasticity of the
atrophic brain (E < 0.2 mL −1 ). Vasogenic waves are rather limited during recording.
The mean ICP increases smoothly during the infusion and decreases in a similar
fashion following infusion, comparable to the inflation and deflation of a balloon –
Fig. 8.17.
8.10.2 Noncommunicating and Acute Communicating
Hydrocephalus
Lumbar infusion is not recommended in noncommunicating hydrocephalus because
of the risk of brain herniation in the event of uncontrolled CSF leak. However,
this type of hydrocephalus may not always be easy to detect by the brain scan.
In those few instances of noncommunicating hydrocephalus where lumbar infusion
is performed, the resistance to CSF outflow is normal because the lumbar infusion
is not able to detect the proximal narrowing in CSF circulatory pathways. Paradoxically elasticity is relatively low (E < 0.20 mL −1 ). In acute hydrocephalus,