Article Figures & Data
Figures
- Fig 1.
Plot of CSF velocity through the cardiac cycle (blue) and for comparison a sinusoid (red). CSF flow has greater velocity in the positive direction (systolic flow) than in the negative direction (diastolic flow). Systolic flow has shorter duration than diastolic flow. Flow volume in the 2 directions is equal.
- Fig 2.
A 3D representation of CSF velocities in an idealized model of the posterior fossa and spinal canal of a patient with Chiari I. It displays the subarachnoid space posteriorly. It shows the direction and magnitude of flow throughout the space at one moment in the cardiac cycle by the direction and length of arrows. Flow velocities and flow directions vary from one region to another. The flow is more rapid at the cervical spine below the tonsils than at the craniovertebral junction. Flow predominates in the long axis of the model but has evidence of vortices in some areas.
- Fig 3.
Four consecutive PCMR images of the 14 images obtained during one cardiac cycle in the upper cervical spine demonstrating flow in the subarachnoid space and in cervical arteries and veins. The first image shows flow anterior and posterior to the spinal cord has a positive sign (caudad direction). The second image shows flow anterolateral to the cord remains positive whereas flow in the midline anterior to the cord has a negative sign (cephalad). The third image shows more voxels with cephalad flow and fewer with caudad flow. The fourth image shows predominantly cephalad flow with little caudad flow detected. The 2 vessels anterolateral to the subarachnoid space have caudad flow in each of the 4 images.
- Fig 4.
Sagittal T2-weighted MR image and coronal slab obtained with 4D PCMR acquisition method. The streamlines in PCMR image shows some flow along the spinal axis and some flow in vortices. Reproduced with permission from: Bunck AC, Kröger JR, Jüttner A, et al. Magnetic resonance 4D flow characteristics of cerebrospinal fluid at the craniocervical junction and the cervical spinal canal. Eur Radiol 2011;21:1788–96.
- Fig 5.
Computer graphic from a flow simulation showing flow along the spinal axis by red-blue-green color coding and in-plane flow by arrows in which velocity is coded by the dimensions of the arrows. Longitudinal flow predominates anterolateral to the cord (top of image) and in-plane flow predominates in a posterior direction. Modified from Roldan et al.7
- Fig 6.
PCMR images in sagittal (upper row) and axial (lower row) views showing flow in one systolic and one diastolic phase of the cycle and for reference (top left) the sagittal T2-weighted image in the patient. These demonstrate more flow anterior to the cord than posterior. On careful inspection, the axial images show more flow anterolateral to the cord than posterior to it. Reproduced with permission from Hofkes SK, Iskandar BJ, Turski PA, et al. Differentiation between symptomatic Chiari I malformation and asymptomatic tonsilar ectopia by using cerebrospinal fluid flow imaging: initial estimate of imaging accuracy. Radiology 2007;245:532–40.
- Fig 7.
Graphic illustrating simulated flow in a patient-specific model of the subarachnoid space to illustrate the inhomogeneity of CSF flow. Flow velocity, in red-blue-green color coding, shows the greatest velocities anterolateral to the spinal cord. Modified from Rutkowska et al.9
- Fig 8.
PCMR images of diastolic flow (left column) and systolic flow (right column) in successively lower levels of the upper cervical spinal canal in a patient with Chiari I. CSF velocities increase from region 1 near the tonsils to region 4 near the C4 level. At C4, aliasing produces negative flow voxels (black) scattered among the voxels with positive flow (white voxels). Modified from Shah et al.8
- Fig 9.
Sagittal T2-weighted image in a patient with a Chiari I malformation and graphic showing simulated flow velocities in the same patient by sagittal and multiple axial sections. The flow simulations show inhomogeneous flow patterns, greatest flow anterolateral to the cord, and increasing velocities between C1 and C4. Reproduced from Rutkowska et al.9
- Fig 10.
Graphic showing pressure gradients along the cervical spinal canal at 4 phases of the cardiac cycle. Pressure is coded by the red-blue-green scale. At one phase, pressure decreases from C1 to C7; at one phase it increases from C1 to C7, and at 2 phases in the cycle, no gradient is present. The pressure oscillates between these pressure patterns during the cycle. Velocities peak approximately 90° out of phase with the pressure in healthy adults. Modified from Roldan et al.7
- Fig 11.
Plot of relative pressure against position from the midposterior fossa to the C3/4 level in 5 computational models: an idealized healthy model, an idealized patient with Chiari I, and 3 models showing the Chiari model with various amounts of craniovertebral decompression. At this phase of the cycle, pressure decreases from posterior fossa to C3/4. The gradients are steepest in the Chiari I model and least steep in the healthy model. The 3 degrees of craniovertebral decompression appear to lower pressures in the foramen magnum and to normalize pressures at the C3/4 level.
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