Radiofrequency saturation induced bias in aqueductal cerebrospinal fluid flow quantification obtained using two‐dimensional cine phase contrast magnetic resonance imaging

Ragunathan, S.; Pipe, James G.

doi:10.1002/mrm.26883

Cited by 6 publications

(4 citation statements)

References 39 publications

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“…Furthermore, our spatial resolution was relatively high (0.45 × 0.45 × 3 mm 3 ), especially regarding slice thickness, reducing partial volume in the aqueduct ROI and thereby resulting in smaller overestimation of net CSF flow. Also, the relatively small slice thickness, short TR, and low flip angle used in this work limited the possible bias in the acquired CSF velocities induced by RF saturation . Finally, a relatively high temporal resolution and SNR were achieved (scanning was performed at 7T, and 36–45 frames per cardiac cycle were acquired, with a temporal resolution of 48 msec), resulting in a relatively high accuracy of the estimated net CSF flow, which is small relative to the stroke volumes.…”

Section: Discussionmentioning

confidence: 99%

Phase contrast MRI measurements of net cerebrospinal fluid flow through the cerebral aqueduct are confounded by respiration

Spijkerman

Geurts

Siero

et al. 2018

Magnetic Resonance Imaging

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Section: Discussionmentioning

confidence: 99%

Phase contrast MRI measurements of net cerebrospinal fluid flow through the cerebral aqueduct are confounded by respiration

Spijkerman

Geurts

Siero

et al. 2018

Magnetic Resonance Imaging

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“…Smaller pixel size reduces partial volume averaging from stationary tissue adjacent to CSF, and is particularly crucial at level of the aqueduct, which is of a much smaller area than the CSF space within the spinal canal at level of the CCJ. The pixel size used for the current study (0.6 × 0.8 mm 2 ) may be considered moderate, and within average used by other investigators (reviewed by ( Ragunathan and Pipe, 2018 )). After a per-pixel aliasing filter was applied as previously described ( Ringstad et al, 2017a ), we now also visually analyzed flow curves from every pixel overlapping with the aqueduct for signs of flow that could be considered not physiological or otherwise influenced by technical error.…”

Section: Discussionmentioning

confidence: 99%

Cerebrospinal fluid volumetric net flow rate and direction in idiopathic normal pressure hydrocephalus

Lindstrøm

Ringstad

Mardal

et al. 2018

NeuroImage: Clinical

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The aim of the present study was to examine cerebrospinal fluid (CSF) volumetric net flow rate and direction at the cranio-cervical junction (CCJ) and cerebral aqueduct in individuals with idiopathic normal pressure hydrocephalus (iNPH) using cardiac-gated phase-contrast magnetic resonance imaging (PC-MRI). An in-depth, pixel-by-pixel analysis of regions of interest from the CCJ and cerebral aqueduct, respectively, was done in 26 iNPH individuals, and in 4 healthy subjects for validation purposes. Results from patients were compared with over-night measurements of static and pulsatile intracranial pressure (ICP). In iNPH, CSF net flow at CCJ was cranially directed in 17/22 as well as in 4/4 healthy subjects. Estimated daily CSF volumetric net flow rate at CCJ was 6.9 ± 9.9 L/24 h in iNPH patients and 4.5 ± 5.0 L/24 h in healthy individuals. Within the cerebral aqueduct, the CSF net flow was antegrade in 7/21 iNPH patients and in 4/4 healthy subjects, while it was retrograde (i.e. towards ventricles) in 14/21 iNPH patients. Estimated daily CSF volumetric net flow rate in cerebral aqueduct was 1.1 ± 2.2 L/24 h in iNPH while 295 ± 53 mL/24 h in healthy individuals. Magnitude of cranially directed CSF net flow in cerebral aqueduct was highest in iNPH individuals with signs of impaired intracranial compliance. The study results indicate CSF flow volumes and direction that are profoundly different from previously assumed. We hypothesize that spinal CSF formation may serve to buffer increased demand for CSF flow through the glymphatic system during sleep and during deep inspiration to compensate for venous outflow.

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“…To ascertain the reliability of our CFD approach we put a lot of effort into optimizing the input data to the simulations, achieving a PCMRI resolution that is far above the average [30]. In addition, CFD simulations were evaluated against bench tests.…”

Section: Discussionmentioning

confidence: 99%

Can pulsatile CSF flow across the cerebral aqueduct cause ventriculomegaly? A prospective study of patients with communicating hydrocephalus

Holmlund

Qvarlander

Malm

et al. 2019

Fluids Barriers CNS

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BackgroundCommunicating hydrocephalus is a disease where the cerebral ventricles are enlarged. It is characterized by the absence of detectable cerebrospinal fluid (CSF) outflow obstructions and often with increased CSF pulsatility measured in the cerebral aqueduct (CA). We hypothesize that the cardiac-related pulsatile flow over the CA, with fast systolic outflow and slow diastolic inflow, can generate net pressure effects that could source the ventriculomegaly in these patients. This would require a non-zero cardiac cycle averaged net pressure difference (ΔPnet) over the CA, with higher average pressure in the lateral and third ventricles.MethodsWe tested the hypothesis by calculating ΔPnet across the CA using computational fluid dynamics based on prospectively collected high-resolution structural (FIESTA-C, resolution 0.39 × 0.39 × 0.3 mm3) and velocimetric (2D-PCMRI, in-plane resolution 0.35 × 0.35 mm2) MRI-data from 30 patients investigated for communicating hydrocephalus.ResultsThe ΔPnet due to CSF pulsations was non-zero for the study group (p = 0.03) with a magnitude of 0.2 ± 0.4 Pa (0.001 ± 0.003 mmHg), with higher pressure in the third ventricle. The maximum pressure difference over the cardiac cycle ΔPmax was 20.3 ± 11.8 Pa and occurred during systole. A generalized linear model verified an association between ΔPnet and CA cross-sectional area (p = 0.01) and flow asymmetry, described by the ratio of maximum inflow/outflow (p = 0.04), but not for aqueductal stroke volume (p = 0.35).ConclusionsThe results supported the hypothesis with respect to the direction of ΔPnet, although the magnitude was low. Thus, although the pulsations may generate a pressure difference across the CA it is likely too small to explain the ventriculomegaly in communicating hydrocephalus.

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Radiofrequency saturation induced bias in aqueductal cerebrospinal fluid flow quantification obtained using two‐dimensional cine phase contrast magnetic resonance imaging

Cited by 6 publications

References 39 publications

Phase contrast MRI measurements of net cerebrospinal fluid flow through the cerebral aqueduct are confounded by respiration

Phase contrast MRI measurements of net cerebrospinal fluid flow through the cerebral aqueduct are confounded by respiration

Cerebrospinal fluid volumetric net flow rate and direction in idiopathic normal pressure hydrocephalus

Can pulsatile CSF flow across the cerebral aqueduct cause ventriculomegaly? A prospective study of patients with communicating hydrocephalus

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