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Cerebrospinal fluid (CSF) flow MRI: Protocol and planning

CSF Flow quantification MRI

A cerebrospinal fluid (CSF) flow MRI is a specialized type of MRI scan used to visualize the flow of cerebrospinal fluid within the brain and spinal canal. In a CSF flow MRI, the goal is to assess the dynamics of this fluid to ensure it is moving properly throughout the brain and spinal column. Disturbances in CSF flow can be indicative of various medical conditions, such as hydrocephalus , spinal stenosis, or Chiari malformations (where brain tissue extends into the spinal canal).

 This imaging technique utilizes specific MRI sequences that are sensitive to the movement of fluids. By using phase-contrast techniques, the MRI can capture and create visual and quantitative data on the direction and speed of CSF flow. This data is crucial for diagnosing abnormalities in fluid pathways and guiding treatment decisions.

The CSF flow MRI uses specific sequences that are sensitive to the movement of fluids within the body. The most common types of sequences used in CSF flow MRI include:

  • Phase-Contrast (PC) MRI Sequences: These are the most widely used sequences for CSF flow studies. They work by measuring phase shifts in the MR signal caused by the movement of CSF. This allows the visualization of the direction and velocity of CSF flow. Phase-contrast sequences can be set to be sensitive to specific directions and speeds of flow, making them highly effective for assessing CSF dynamics.
  • Cine MRI: This technique captures multiple frames within a cycle of CSF movement, effectively creating a video of CSF flow. Cine MRI is beneficial in showing how CSF flow changes over time.
  • 3D Volumetric Sequences: These sequences provide detailed three-dimensional images of the CSF spaces and can be helpful in assessing the overall anatomy and any potential abnormalities affecting CSF flow

Through-plane CSF flow MRI images

Re-phased Image

Re-phased Image of Phase-contrast (PC) sequence used in CSF flow imaging

Magnitude Image

Magnitude Image of Phase-contrast (PC) sequence used in CSF flow imaging

Phase Image

Phase Image of Phase-contrast (PC) sequence used in CSF flow imaging

indications for Cerebrospinal fluid (CSF) flow MRI

Contraindications

Patient preparation for CSF flow MRI

Positioning for CSF Flow MRI

mri brain planning and positioning

Pulse gating technique

Cerebrospinal fluid (CSF) flow imaging is performed using pulse gating techniques to synchronize the imaging with the cardiac cycle. This synchronization is crucial because the flow of CSF is influenced by the cardiac pulse, which causes periodic fluctuations in the pressure gradients across the central nervous system. As the heart beats, it not only pumps blood but also subtly affects the movement of CSF, making its dynamics inherently pulsatile.

Pulse gating in CSF flow imaging typically involves the use of electrocardiogram (ECG) or peripheral pulse gating to capture the precise phases of the cardiac cycle. By coordinating the MRI scans with these phases, it becomes possible to obtain highly detailed and dynamic images of CSF flow. This method allows for the measurement of CSF velocity and flow patterns at different times within the cardiac cycle, providing a comprehensive view of its temporal and spatial variations.

CSF flow pulse signal image

Recommended CSF Flow MRI Protocols and Planning

Localiser

A three-plane localizer must be taken at the beginning to localize and plan the sequences. Localizers are usually less than 25 seconds and are T1-weighted low-resolution scans.

Brain MRI localiser image

T2 tse axial

Plan the axial slices on the sagittal plane and position the block parallel to the genu and splenium of the corpus callosum. Verify the planning block in the other two planes and ensure that an appropriate angle is maintained in the coronal plane, making it perpendicular to the line of the midline of the brain and the 4th ventricle. Ensure that the number of slices is sufficient to cover the entire brain from the vertex to the line of the foramen magnum.

mri brain protocol and planning of axial scans

Protocol Parameters of T2

TR

4000-5500

TE

100-120

SLICE

3MM

FLIP

130-150

PHASE

R>L

MATRIX

320X320

FOV

210-230

GAP

10%

NEX(AVRAGE)

2

T2 FLAIR coronal

Plan the coronal slices on the sagittal plane and angle the planning block perpendicular to the line along the genu and splenium of the corpus callosum. Verify the planning block in the other two planes. Ensure that an appropriate angle is maintained in the axial plane, perpendicular to the midline of the brain. The number of slices should be sufficient to cover the entire brain from the frontal sinus to the line of the occipital protuberance.

mri brain protocol and planning of coronal scansscans

Protocol Parameters of FLAIR

TR

7000-9000

TE

110

FLIP

130

NEX

2

SLICE

3MM

MATRIX

320X320

FOV

210-230

PHASE

R>L

GAP

10%

TI

2500

T2 SPACE 3D Mid-brain Sagittal 0.5 mm

Plan the sagittal slices on the axial plane and position the block parallel to the midline of the brain. Verify the planning block in the other two planes. Angle the planning block appropriately in the coronal plane, ensuring it is parallel to the line along the midline of the brain and the fourth ventricle. Make sure that the number of slices is sufficient to cover the entire brainstem from one side to the other.

Protocol Parameters of SPACE 3D

TR

2500-3500

TE

100-130

SLICE

.5mm

FLIP

80

PHASE

R>L

MATRIX

330X320

FOV

210-230

GAP

20%

NEX(AVRAGE)

1

3D SPACE sagittal Images

T2 SPACE 3D Mid-brain Sagittal 0.5 mm 2
T2 SPACE 3D Mid-brain Sagittal 0.5 mm 6
T2 SPACE 3D Mid-brain Sagittal 0.5 mm 3
T2 SPACE 3D Mid-brain Sagittal 0.5 mm 6

CSF flow and VENC settings

Normal CSF flow velocities can vary significantly based on the individual, the location measured, and physiological conditions, but general guidelines include:

  • Peak systolic velocities range from 5 to 10 cm/s in the cerebral aqueduct.
  • VENC settings are often set around 5 to 25 cm/s, depending on the expected velocity of CSF flow in the region of interest.

The ideal method for conducting a CSF flow sequence involves using a VENC scout to identify the optimal flow value. However, radiographers often find it challenging to determine this optimal value. For this reason, we prefer to perform multiple scans with different VENC settings. Since the scan time is very short per sequence, performing multiple VENC scans takes almost the same amount of time as performing the scans with a VENC scout.

CSF flow through- plane scan protocol and planning

CSF flow through plane VENC 6cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

42.3

TE

3.1

FLIP

20

NEX

1

SLICE

6MM

MATRIX

208×192

FOV

200

PHASE

R>L

VELOCITY

 6cm\sec  

TRIGGER

Pulse

CSF flow study image Images

Re-phased Image

Re-phased Image of Phase-contrast (PC) sequence used in CSF flow imaging

Magnitude Image

Magnitude Image of Phase-contrast (PC) sequence used in CSF flow imaging

Phase Image

Phase Image of Phase-contrast (PC) sequence used in CSF flow imaging

CSF flow through plane VENC 10cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

21.1

TE

6.38

FLIP

20

NEX

1

SLICE

6MM

MATRIX

224×205

FOV

160

PHASE

A>P

VELOCITY

 10cm\sec  

TRIGGER

Pulse/Retro

CSF flow through plane VENC 15cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

21.1

TE

6.38

FLIP

20

NEX

1

SLICE

6MM

MATRIX

224×205

FOV

160

PHASE

A>P

VELOCITY

 15cm\sec  

TRIGGER

Pulse/Retro

CSF flow through plane VENC 20cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

21.1

TE

6.38

FLIP

20

NEX

1

SLICE

6MM

MATRIX

224×205

FOV

160

PHASE

A>P

VELOCITY

 20cm\sec  

TRIGGER

Pulse/Retro

CSF flow through plane VENC 25cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

21.1

TE

6.38

FLIP

20

NEX

1

SLICE

6MM

MATRIX

224×205

FOV

160

PHASE

A>P

VELOCITY

 25cm\sec  

TRIGGER

Pulse/Retro

CSF flow through plane VENC 30cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

21.1

TE

6.38

FLIP

20

NEX

1

SLICE

6MM

MATRIX

224×205

FOV

160

PHASE

A>P

VELOCITY

 30cm\sec  

TRIGGER

Pulse/Retro

CSF flow through plane VENC 45cm\sec

Plan the axial flow sequence using the sagittal 3D SPACE image that shows the cerebral aqueduct, and position the block perpendicular to the cerebral aqueduct. Verify the placement of the planning block in the other two planes, ensuring that it maintains an appropriate angle in the coronal plane, making it perpendicular to the brain’s midline.

Protocol Parameters

TR

21.1

TE

6.38

FLIP

20

NEX

1

SLICE

6MM

MATRIX

224×205

FOV

160

PHASE

A>P

VELOCITY

 45cm\sec  

TRIGGER

Pulse/Retro

The post-processing of the study is performed by the radiologist at the workstation. Each manufacturer has its own post-processing software. However, if anyone is interested in learning more about this, please refer to the manufacturer’s scanner manual.

CSF flow in- plane scan protocol and planning

CSF flow in-plane VENC 6cm\sec

Plan the sagittal flow sequence on the axial plane and position the block parallel to the midline of the brain. Verify the planning block in the other two planes. Angle the planning block appropriately in the coronal plane to ensure it is parallel to the line along the midline of the brain and the third ventricle. Make sure that pulse gating is enabled in the protocol.

MRI CSF flow in- plane scan protocol and planning

Protocol Parameters

TR

23.7

TE

7.78

FLIP

20

NEX

1

SLICE

6MM

MATRIX

256×205

FOV

180

PHASE

A>P

VELOCITY

 6cm\sec  

TRIGGER

Pulse/Retro

CSF flow study image Images

Re-phased Image

Magnitude Image

Phase Image

Re-phased Image

Magnitude Image

Phase Image

Re-phased Image

Magnitude Image

Phase Image

CSF flow in-plane VENC 11cm\sec

Plan the sagittal flow sequence on the axial plane and position the block parallel to the midline of the brain. Verify the planning block in the other two planes. Angle the planning block appropriately in the coronal plane to ensure it is parallel to the line along the midline of the brain and the third ventricle. Make sure that pulse gating is enabled in the protocol.

MRI CSF flow in- plane scan protocol and planning

Protocol Parameters

TR

23.7

TE

7.78

FLIP

20

NEX

1

SLICE

6MM

MATRIX

256×205

FOV

180

PHASE

A>P

VELOCITY

 11cm\sec  

TRIGGER

Pulse/Retro

CSF flow in-plane VENC 20cm\sec

Plan the sagittal flow sequence on the axial plane and position the block parallel to the midline of the brain. Verify the planning block in the other two planes. Angle the planning block appropriately in the coronal plane to ensure it is parallel to the line along the midline of the brain and the third ventricle. Make sure that pulse gating is enabled in the protocol.

MRI CSF flow in- plane scan protocol and planning

Protocol Parameters

TR

23.7

TE

7.78

FLIP

20

NEX

1

SLICE

6MM

MATRIX

256×205

FOV

180

PHASE

A>P

VELOCITY

 20cm\sec  

TRIGGER

Pulse/Retro

CSF flow in-plane VENC 25cm\sec

Plan the sagittal flow sequence on the axial plane and position the block parallel to the midline of the brain. Verify the planning block in the other two planes. Angle the planning block appropriately in the coronal plane to ensure it is parallel to the line along the midline of the brain and the third ventricle. Make sure that pulse gating is enabled in the protocol.

MRI CSF flow in- plane scan protocol and planning

Protocol Parameters

TR

23.7

TE

7.78

FLIP

20

NEX

1

SLICE

6MM

MATRIX

256×205

FOV

180

PHASE

A>P

VELOCITY

 25cm\sec  

TRIGGER

Pulse/Retro