Intravascular BOLD signal characterization of balanced SSFP experiments in human blood at high to ultrahigh fields

Pérez-Rodas, M; Pohmann, R; Scheffler, Klaus; Heule, Rahel

doi:10.1002/mrm.28575

Cited by 4 publications

(7 citation statements)

References 56 publications

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“…This may be because the on-resonance signal of 2D bSSFP is much more stable and less sensitive to flow than banding signal. 44 In addition, bSSFP is sensitive to intravascular BOLD responses from large veins, 6,11,45 which always lead to high signal changes. These voxels with abnormally high signal changes may be removed by setting a threshold while preserving activation with high tissue or microvascular specificity.…”

Section: Discussionmentioning

confidence: 99%

Multi‐echo balanced SSFP with a sequential phase‐encoding order for functional MR imaging at 7T

Liang

Pan

Cui

et al. 2022

Magnetic Resonance in Med

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To develop a 2D multi-echo passband balanced SSFP (bSSFP) sequence using an echo-train readout with a sequential phase-encoding order (sequential multi-echo bSSFP), and evaluate its performance in fast functional brain imaging at 7 T. Methods:As images of sequential multi-echo bSSFP exhibit multiple ghosts due to periodic k-space modulations, a GRAPPA-based reconstruction method was proposed to eliminate ghosting artifacts. MRI experiments were performed to compare the image quality of multi-echo bSSFP and conventional single-echo bSSFP. Submillimeter-resolution fMRI using a checkerboard visual stimulus was conducted to compare the activation characteristics of multi-echo bSSFP, conventional single-echo bSSFP and standard gradient-echo EPI (GE-EPI).Results: A higher mean structural similarity index was found between images of single-echo bSSFP and multi-echo bSSFP with a shorter echo train length (ETL).Multi-echo bSSFP (ETL = 3) showed higher temporal SNR (tSNR) values than GRAPPA-accelerated single-echo bSSFP (R = 2). In submillimeter-resolution fMRI experiments, multi-echo bSSFP (ETL = 3) approached the imaging speed of GRAPPA-accelerated single-echo bSSFP (R = 2), but without tSNR penalty and reduced activation due to acceleration. The median t-value and the number of significantly activated voxels were comparable between GE-EPI and multi-echo bSSFP (ETL = 3) that provides virtually distortion-free functional images and inherits the activation patterns of conventional bSSFP.

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Section: Discussionmentioning

confidence: 99%

Multi‐echo balanced SSFP with a sequential phase‐encoding order for functional MR imaging at 7T

Liang

Pan

Cui

et al. 2022

Magnetic Resonance in Med

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“…For CPMG, the intravascular contribution is similar to single-spin echoes as long as echo spacing is not too short (below 10-15 ms 32 ), which is in the range of 10% to 30%. 33 This contribution can be reduced with low refocusing flip angles, which does not drastically reduce the BOLD sensitivity of CPMG.…”

Section: Discussionmentioning

confidence: 99%

“…The contribution of intravascular signal changes originates from changes in blood T 2 with oxygenation level, possible flow or inflow effects, and chosen sequence parameters. For CPMG, the intravascular contribution is similar to single‐spin echoes as long as echo spacing is not too short (below 10‐15 ms 32 ), which is in the range of 10% to 30% 33 . This contribution can be reduced with low refocusing flip angles, which does not drastically reduce the BOLD sensitivity of CPMG.…”

Section: Discussionmentioning

confidence: 99%

BOLD sensitivity and vessel size specificity along CPMG and GRASE echo trains

Scheffler

Engelmann

Heule

2021

Magnetic Resonance in Med

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“…weighted and although it is a GRE sequence, echo formation at TE = TR/2 (which is used in this work) is similar to SE, meaning that the transverse magnetization is (nearly) refocused when the echo is acquired (Scheffler & Hennig, 2003). In theory, the SE-like signal of bSSFP shows increased selectivity to the microvasculature at high fields (Bowen et al, 2005) with a high intravascular contribution (Pérez-Rodas et al, 2021). This theoretical expectation was further strengthened by Monte Carlo simulations using sections of vascular networks of the mouse parietal cortex (Báez-Yánez et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…For sequences with reduced macrovascular contribution, like bSSFP, the orientation dependence should be lower, since the intravascular effect dominates at 3 T and 9.4 T, especially in the macrovasculature and for short repetition times (TRs) (Pérez-Rodas et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Macrovascular contributions to resting-state fMRI signals: A comparison between EPI and bSSFP at 9.4 Tesla

Ramadan,

Mueller,

Stirnberg

et al. 2024

Preprint

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The draining-vein bias of T2*-weighted sequences, like gradient echo echo-planar imaging (GRE-EPI), can limit the spatial specificity of functional MRI (fMRI). The underlying extravascular signal changes increase with field strength (B0) and the perpendicularity of draining veins to the main axis of B0, and are therefore particularly problematic at ultra-high field (UHF). In contrast, simulations showed that T2-weighted sequences are less affected by the draining-vein bias, depending on the amount of rephasing of extravascular signal. As large pial veins on the cortical surface follow the cortical folding tightly, their orientation can be approximated by the cortical orientation to. In our work, we compare the influence of the cortical orientation toon the resting-state fMRI signal of three sequences aiming to understand their macrovascular contribution. While 2D GRE-EPI and 3D GRE-EPI (both T2*-weighted) showed a high dependence on the cortical orientation to, especially on the cortical surface, this was not the case for 3D balanced steady-state free precession (bSSFP) (T2/T1-weighted). Here, a slight increase of orientation dependence was shown in depths closest to WM. And while orientation dependence decreased with increased distance to the veins for both EPI sequences, no change in orientation dependence was observed in bSSFP. This indicates the low macrovascular contribution to the bSSFP signal, making it a promising sequence for layer fMRI at UHF.

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Intravascular BOLD signal characterization of balanced SSFP experiments in human blood at high to ultrahigh fields

Abstract: This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Cited by 4 publications

References 56 publications

Multi‐echo balanced SSFP with a sequential phase‐encoding order for functional MR imaging at 7T

Multi‐echo balanced SSFP with a sequential phase‐encoding order for functional MR imaging at 7T

BOLD sensitivity and vessel size specificity along CPMG and GRASE echo trains

Macrovascular contributions to resting-state fMRI signals: A comparison between EPI and bSSFP at 9.4 Tesla

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