Hemodynamically independent analysis of cerebrospinal fluid and brain motion observed with dynamic phase contrast MRI

Abstract

Brain and cerebrospinal fluid (CSF) movements are influenced by the anatomy and mechanical properties of intracranial tissues, as well as by the waveforms of driving vascular pulsations. The authors analyze these movements so that the purely hemodynamic factors are removed and the underlying mechanical couplings between brain, CSF, and the vasculature are characterized in global fashion. These measurements were used to calculate a set of impulse response functions or modulation transfer functions, characterizing global aspects of the vasculature's mechanical coupling to the intracranial tissues, the cervical CSF, and the cervical spinal cord. These functions showed that a sudden influx of blood into the head was rapidly accommodated by some type of intracranial reserve or capacity. After this initial response, an equal volume of CSF was driven through the foramen magnum over the next 200-300 ms as the intracranial reserve relaxed to its base-line state.

Visualization of Pulsatile CSF Motion Around Membrane-like Structures with both 4D Velocity Mapping and Time-SLIP Technique

“…5,6,16,32 Moreover, in the normal intracranial environment, synchronization among arterial, CSF, and venous velocity waveforms has been demonstrated by evaluation of the velocities of these components at the axial slice of the cervical region. [13][14][15]17 However, the Windkessel effect should prevent transmission of arterial pulse waveforms to CSF through the capillaries 32 because the compliance of the arterial wall will change pulsatile arterial flow to stationary flow. Therefore, the to-and-fro motion of the CSF within a cardiac cycle can be primarily attributed to the propagation of pressure from the cerebral arteries rather than the capillaries.…”

“…Many studies have used time-resolved 2-dimensional (2D) phase-contrast or 3-dimensional (3D) MR velocity mapping in the quantitative and qualitative evaluation of regional CSF pulsation [13][14][15][16][17][18] or motion of brain parenchyma 15,19,20 during the cardiac cycle. Recently, time-resolved 3D phase-contrast or 4-dimensional (4D) velocity mapping (4D-VM) techniques have been applied to the ventricular system 21,22 and craniocervical junction 23 to analyze spatiotemporal CSF hydrodynamics in an extensive field.…”

Abnormalities of CSF flow patterns in the cerebral aqueduct in treatment‐resistant late‐life depression: A potential biomarker of microvascular angiopathy

“…If so, then corresponding secondary abnormalities in the flow of CSF through the cerebral aqueduct (earlier onset and reduced duration of the systolic CSF flow peak) should be observable by MRI. In previous studies, phase-contrast (PC) MRI measurement of blood and CSF flow was used to investigate the mechanical properties of brain parenchyma (21,22) and to detect variations in flow due to communicating hydrocephalus (23,24). If such changes are detectable in patients with MVA, they could provide a valuable quantitative biomarker of the severity of MVA, which would be of particular use in the development and testing of novel therapeutic agents that target the cerebral vasculature.…”

Magnetic resonance imaging–based measures predictive of short-term surgical outcome in patients with Chiari malformation Type I: a pilot study

“…It seems that effective decompressive surgery restores sufficient craniospinal CSF flow to accommodate the systolic increase in intracranial blood volume during each cardiac cycle. 7,8 The measurement of cord displacement is derived from the transverse cine phase-contrast scan commonly performed to visualize and/or measure craniospinal CSF flow at the upper-cervical region. Therefore, this important indicator can be readily available as part of a routine clinical MRI scan for the diagnosis of CM-I.…”

“…The lack of consistency related to CSF-velocity measures is likely a result of the documented large interindividual variability in CSF craniospinal velocities. 8 The multivariate analysis yielded somewhat different sets of predictors depending on the outcome classification used. The percent cerebral venous drainage through the jugular veins was identified as an outcome predictor when chief complaint was used for outcome classification.…”