Assessment of non-protonated perflubron liquid-filled padding on cervical and lumbar spinal fMRI
Poster No:
1935
Submission Type:
Abstract Submission
Authors:
Olivia Kowalczyk1, Matthew Howard2, David Lythgoe2
Institutions:
1King's College London / University College London, London, London, 2King's College London, London, United Kingdom
First Author:
Co-Author(s):
Introduction:
Spinal fMRI has progressed significantly in recent years, revealing insights into the function of somatosensory and motor systems. However, challenges remain in acquiring high-quality spinal fMRI data due to the small size and complex environment of the spinal cord, as well as proximity to dynamic physiological systems (Kinany et al., 2022). Here we investigate the effects of perflubron liquid-filled pads (SatPadTM, https://satpads.com) – a susceptibility-matched padding technology – on cervical and lumbar spinal fMRI quality.
Methods:
Healthy adult volunteers (N=10, 29±4 years) completed two resting-state fMRI scanning sessions – one of the cervical spinal cord (38 slices, slice thickness=4mm, slice gap=1mm, TR=2.5s, TE=30ms, flip angle=90°, ASSET factor=2, FOV=180mm, acquisition matrix=96×96, in‐plane voxel size=1.41mm×1.41mm) and one of lumbar spinal cord (23 slices, slice thickness=4mm, slice gap=1mm, TR=1.6s, TE=30ms, flip angle=90°, ASSET factor=2, FOV=150 mm, acquisition matrix=96×96, in-plane voxel size=1.17x1.17mm). Within each session, participants were scanned with and without SatPadTM in a pseudorandomised order. For all scans, a spectral-spatial excitation pulse was used to excite only tissue water. Static 0th, 1st, and 2nd order shims were optimised and slice-specific shims were implemented by adding 0.6ms duration x-, y- & z-gradient lobes after the excitation pulse (Tsivaka et al., 2023).
Minimal preprocessing was performed on the data to avoid artificially inflating outcome measures. Data were motion-corrected for x- and y-translations (https://neptunetoolbox.com/) and registered to the PAM50 template (De Leener et al., 2018) via a subject-specific T2-weighted image. Nearest neighbour interpolation was used for motion correction and registration to avoid modifying the noise characteristics of the data.
Temporal signal-to-noise ratio (tSNR) was calculated on motion-corrected data by dividing the mean functional image by its standard deviation. Mean tSNR was extracted for the whole cervical and lumbar cord, as well as for individual segmental levels in each cord section (C1-C8 and L1-L5). The effects of participant motion were characterised as framewise displacement (FD) and the spatial root mean square of the data after temporal differencing (DVARS). Wilcoxon rank tests were used to compare tSNR, FD, and DVARS of data obtained with SatPadTM and without. Qualitative assessment of geometric distortions and ghosting artifacts was performed.
Minimal preprocessing was performed on the data to avoid artificially inflating outcome measures. Data were motion-corrected for x- and y-translations (https://neptunetoolbox.com/) and registered to the PAM50 template (De Leener et al., 2018) via a subject-specific T2-weighted image. Nearest neighbour interpolation was used for motion correction and registration to avoid modifying the noise characteristics of the data.
Temporal signal-to-noise ratio (tSNR) was calculated on motion-corrected data by dividing the mean functional image by its standard deviation. Mean tSNR was extracted for the whole cervical and lumbar cord, as well as for individual segmental levels in each cord section (C1-C8 and L1-L5). The effects of participant motion were characterised as framewise displacement (FD) and the spatial root mean square of the data after temporal differencing (DVARS). Wilcoxon rank tests were used to compare tSNR, FD, and DVARS of data obtained with SatPadTM and without. Qualitative assessment of geometric distortions and ghosting artifacts was performed.
Results:
SatPadTM use led to a 13% increase in tSNR in the cervical cord (W=4, p=0.014, rrb=-0.86) and an 11% increase in the lumbar cord (albeit not statistically significant, W=17, p=0.322, rrb=-0.38). A 61% reduction in FD was associated with SatPadTM use in the lumbar cord (W=47, p=0.049, rrb=0.71) but less than 1% difference in cervical cord (W=27, p=1, rrb=-0.02). No differences were observed in DVARS. Fewer geometric distortions and reduced ghosting artifacts were also associated with SatPadTM use.
·Temporal signal-to-noise ratio group-level maps at baseline (left panel) and with SatPadTM (right panel), for cervical (top panel) and lumbar spinal cord acquisition (bottom panel).
Conclusions:
These data demonstrate the utility of SatPadTM in enhancing spinal fMRI data quality. SatPadTM use significantly improved tSNR in the cervical cord and showed a non-significant yet meaningful increase in lumbar tSNR, reflecting promising advancements for this developing imaging area. Additionally, the marked reduction in motion artifacts in the lumbar cord, coupled with fewer geometric distortions and ghosting artefacts across both sections of the cord, aligns with initial expectations that SatPadTM would lessen the impact of some of the specific challenges related to spinal fMRI data acquisition. These improvements hold potential for more reliable interpretation of spinal fMRI data, facilitating its broader application in both basic and clinical research. This study offers a compelling basis for integrating susceptibility-matched padding into routine spinal fMRI protocols.
Novel Imaging Acquisition Methods:
BOLD fMRI 2
Imaging Methods Other 1
Keywords:
FUNCTIONAL MRI
Spinal Cord
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Was this research conducted in the United States?
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.
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Provide references using APA citation style.
Kinany, N., Pirondini, E., Micera, S., & Van De Ville, D. (2022). Spinal Cord fMRI: A New Window into the Central Nervous System. The Neuroscientist, 10738584221101827.
Tsivaka, D., Williams, S. C. R., Medina, S., Kowalczyk, O. S., Brooks, J. C. W., Howard, M. A., ... & Tsougos, I. (2023). A second-order and slice-specific linear shimming technique to improve spinal cord fMRI. Magnetic Resonance Imaging, 102, 151-163.