2. FORMATION & ABSORBTION OF CSF
Most of this fluid originates from choroid
plexuses of the four ventricles. Additional
amounts of fluid are secreted by ependymal
surfaces of ventricles & arachnoidal
membranes.
500 mL of CSF is formed each day
CSF is absorbed by multiple arachnoidal villi
4. Following conditions can change CSF dynamics
Communicating hydrocephalus
Non-communicating hydrocephalus
Arachnoid cyst
Chiari malformation
Syringomyelic cyst
AfterVP shunting ( To assess the function of shunt)
5. Basic principles :-
* CSF circulation is related to the cardiac
cycle.
*During systole as blood flow into the
brain…, CSF
flows down the aqueduct of sylvius.
*During diastole the reverse occurs.
So, CSF systole is characterized by caudal
CSF Motion & CSF diastole by cranial CSF
motion
6. The most common technique used is time resolved 2D phase
contrast MRI with velocity encoding.
specific sequential application of a pair of phase
encoding pulses in opposite directions. Stationary
protons will experience the same pulse at both times
and therefore return no signal. Protons that have
moved will experience different phase encoding
pulses and will thus be visible .
7. The sequence of time resolved 2D phase contrast MRI with
velocity encoding help us in two ways
1.Quantitatively
2. Qualitatively
8. For Quantitative
Axial technique: CSF flow dynamics were
quantitatively studied by using a cardiac
gated (Peripheral ECG gating being used for
cardiac synchronization) high resolution axial
phase contrast.
9. Axial planning for Quantitative measurements
protocol with an
imaging plane
perpendicular to the
proximal 1/3 of the
cerebral aqueduct. The
direction of flow
encoding was
caudocranial (from
below upwards).
10. Axial phase images are then obtained showing the
aqueduct as a rounded structure (in cross section).
(12-16 phase image are obtained alternating systole
& diastole)
Axial phase images are showing the aqueduct as a
rounded structure. In systolic phase CSF is dark
and white in diastolic due to low and high signal.
11. For qualitative assessment of CSF flow
For qualitative
assessment of CSF
flow, midsagittal phase
contrast images were
obtained with in-plane
velocity encoding in
the caudocranial
direction which signs
low signal to
craniocaudal CSF
displacement
13. Patient preparation
1. Routine MRI brain preparation will do.
Look for any metallic , paramagnetic
materials and electronic devices. Since they
are not allowed in MRI room.
2. Get consent form
14. Selection of sequences for MRI CSF flow
study 1.SURVEY 2. CSF-DRIVE 3.CSF-QF
4.CSF-PCA 5.POST processing.
15. CSF-drive planning- It is used to get thin
T2W images. planned at mid sagittal plane on scout. The
plan is shown below.
20. Data for healthy volunteers
Analysis revealed that in the control group, the mean
systolic velocity at the level of the aqueduct was
around 1.18 cm/sec (+/- 0.47).
The peak systolic velocity was around 2.27 cm/sec
(+/- 0.94).
Also we obtained a mean value of 27.26microliters (+/-
3.5) for the aqueductal systolic stroke volume in
healthy volunteers.
21. Parameters 1 2 3 4 5
End diastolic peak
velocity (cm/s)
0.37 1.68 1.91 4.02 2.36
Systolic peak
velocity (cm/s)
0.69 2.54 2.41 3.24 2.49
Systolic mean
velocity (cm/s)
0.35 1.455 1.50 1.346 1.251
Time of CSF peak
systole (mm/s)
218 190 258 339 214
Onset of CSF
systole (mm/s)
125 120 120 120 577
End of CSF systole
(mm/s)
270 440 480 450 299
Duration of CSF
systole (mm/s)
145 320 360 330 363
Aqueductal area
(mm)
0.053 0.054 0.055 0.051 0.125
Mean systolic flux
(ml/s)
0.018 0.885 0.087 0.08 0.066
Systolic stroke
volume (μl/s)
26 28.3 32 26 24
An overview of the measured and calculated parameters of
the aqueductal CSF flow in normal volunteers.
22. In NPH cases
Pathological CSF flow dynamics in normal
pressure hydrocephalus, The systolic peak
velocity and the systolic stroke volume values
were statistically significantly higher than those
of the normal controls, these results indicate
that patients with normal pressure
hydrocephalus have hyperdynamic aqueductal
CSF flow. In NPH cases , systolic stroke
volume are above 60 microliters
23. Parameters 1 2 3 4 5 6 7 8 9
End diastolic peak
velocity (cm/s) 4.31 3.86 3.85 2.74 2.68 1.48 3.51 2.82 2.72
Systolic peak
velocity (cm/s) 4.27 4.27 4.79 6.97 3.87 2.26 5.32 3.78 4.42
Systolic mean
velocity (cm/s) 1.91 2.473 12.94 3.918 2.09 1.264 6.34 5.54 6.76
Time of CSF peak
systole (mm/s) 225 305 401 351 307 296 505 440 385
Onset of CSF systole
(mm/s) 149 200 260 175 160 162 180 170 135
End of CSF systole
(mm/s) 449 520 640 550 620 592 510 550 620
Duration of CSF
systole (mm/s) 300 350 380 375 460 430 330 380 485
Aqueductal area
(mm) 1.58 0.124 0.148 0.117 0.098 0.155 0.198 1.231 1.553
Mean systolic flux
(ml/s) 0.304 0.332 0.304 0.489 0.206 0.275 0.339 0.335 0.195
Systolic stroke
volume (μl/s) 91 106 116 183 94 118 112 135 95
An overview of the measured and calculated parameters of aqueductal
CSF flow in NPH patients with very high stroke volume.
24. In Cerebral atrophy
In cerebral atrophy, blood flow to the
brain is decreased; we found markedly
lower systolic peak velocity, systolic
mean velocity and stroke volume
values in comparison to healthy
volunteers indicating a hypodynamic
CSF circulation. Systolic stroke
volume are around 10 microliters
25. Parameters 1 2 3 4 5 6
End diastolic peak velocity
(cm/s) 0.54 2.37 2.36 4.02 3.21 2.12
Systolic peak velocity (cm/s)
0.47 1.38 2.49 3.24 1.96 1.51
Systolic mean velocity (cm/s)
0.52 0.76 1.25 1.34 1.12 0.94
Time of CSF peak systole
(mm/s) 244 551 342 339 345 420
Onset of CSF systole (mm/s)
140 320 215 220 180 230
End of CSF systole (mm/s)
435 860 575 450 530 620
Duration of CSF systole (mm/s)
295 540 360 230 350 390
Aqueductal area (mm)
1.44 0.056 0.052 0.051 0.042 0.054
Mean systolic flux (ml/s)
0.036 0.038 0.065 0.081 0.051 0.041
Systolic stroke volume (μl/s)
10.6 13 16 13.2 12.2 12.7
Table 4. An overview of the measured and calculated parameters of aqueductal CSF flow in patients with
involutional brain changes.
26. MRI CSF dynamics results are used by many
research studies. This is study of CSF
flow before and after VP shunt.
27. Summary
Formation and absorption of CSF
Conditions changing CSF flow dynamics
Quantitative & qualitative assessment
Selection of sequence
Survey
CSF drive
CSF QF
CSF PCA
Post processing
Systolic stroke volume
Normal case (27.26 micro liters)
NPH case (>60 micro liters)
Cerebral atrophy (10 micro liters)
28. Thanks
Thanks for RITE 2018 for this opportunity given to
me .
Thanks for Prof.Dr.I.Gurubharath.
