Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla

Shao, Xingfeng; Guo, Fanhua; Shou, Qinyang; Wang, Kai; Jann, Kay; Yan, Lirong; Toga, Arthur W.; Zhang, Peng; Wang, Danny J.J.

doi:10.1016/j.neuroimage.2021.118724

Cited by 19 publications

(51 citation statements)

References 88 publications

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“…However, its weighting towards macrovasculature is well established (Menon, 2012;Turner, 2002;Uludaǧ et al, 2009;Yacoub et al, 2003) and needs to be dealt with for laminar purposes where spatial specificity is of the essence. The superficial bias that follows from large vein sensitivity was clearly present in the NORDICmagn profiles which indeed possessed the characteristic positive gradient from WM to CSF (Figure 4A and Figure 5B) consistently found with GE-BOLD (Aitken et al, 2020;de Hollander et al, 2021;Han et al, 2021;Huber et al, 2015;Kok et al, 2016;Shao et al, 2021;Stanley et al, 2020) (see also Figure S3). Also, activation maps revealed higher percent signal changes towards the surface and in CSF which adds to the evidence for large vein contamination (Figure 4B).…”

Section: Specificitysupporting

confidence: 68%

“…Although we do believe that the lack of two distinct peaks is partly explained by macrovascular influence, it may also be explained by the fact that we extract signal from relatively large ROIs spanning several slices (Han et al, 2021;Pais-Roldán et al, 2020). Moreover, not all subjects have double peak profiles even with non-GE-BOLD sequences (Beckett et al, 2020;Shao et al, 2021), thus we cannot rule out that more distinct peaks would emerge in the group profile with different subjects. Third, NORDICmicro activation maps still contain CSF voxels with strong percent signal changes (Figure 4B).…”

Section: Specificitymentioning

confidence: 93%

“…ROIs were manually defined in the hand knob area of Brodmann area 4a (BA4a) similarly to previous layer-fMRI reports focusing on M1 and finger tapping (Beckett et al, 2020;Chai et al, 2020;Han et al, 2021;Huber et al, 2017;Persichetti et al, 2020;Shao et al, 2021). First, the hand knob was visually identified from its characteristic omega-shape (Yousry et al, 1997) and voxel selection was then limited to the upper and lateral part of the knob corresponding to BA4a (Huber et al, 2017).…”

Section: Roi Definition and Segmentationmentioning

confidence: 99%

“…After segmentation, the set of voxels constituting the ROI was selected to maximize the signal in depths 0.3-0.4 (deep layers). 0.3 was chosen as lower bound to minimize partial voluming with WM and 0.4 was chosen as upper bound due to expected signal reductions in middle layers (Chai et al, 2020;Huber et al, 2017;Shao et al, 2021). This selection was restricted by the following criteria: 1) ROIs were defined as columns (no holes) going roughly perpendicular onto the surface to make it somewhat anatomical meaningful; 2) ROIs had to consist of minimum 50 voxels to increase the ability to compare the same cortical portion across sessions despite e.g.…”

Section: Roi Definition and Segmentationmentioning

confidence: 99%

“…positioning not being fully identical, to minimize influence of inaccuracies in e.g., segmentation or across session alignment, and to increase representability of measured M1 activation; 3) ROIs should not extend into more than four slices; 4) the peak signal in depths 0.3-0.4 should not exceed that of depths 0.6-0.8 in order to identify the same functional representation as previous M1 layer-fMRI studies, which generally found stronger activity in superficial compared to deep layers (Beckett et al, 2020;Chai et al, 2020;Han et al, 2021;Huber et al, 2017;Shao et al, 2021); 5) Empty axial slices were not allowed in the final union ROI (see below), that is, it had to be consecutive. These initial ROIs defined in native space of each individual session were then transformed into the space of each subject's first session where the union of all ROIs was computed and transformed back to native space (Figure 1).…”

Section: Roi Definition and Segmentationmentioning

confidence: 99%

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Feasibility of 3T layer-dependent fMRI with GE-BOLD using NORDIC and phase regression

Knudsen

Bailey

Blicher

et al. 2022

Preprint

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Introduction: Functional MRI with spatial resolution in the submillimeter domain enables measurements of activation across cortical layers in humans. This is valuable as different types of cortical computations, e.g., feedforward versus feedback related activity, take place in different cortical layers. Layer-dependent fMRI (L-fMRI) studies have almost exclusively employed 7T scanners to overcome the reduced signal stability associated with small voxels. However, such systems are relatively rare and only a subset of those are clinically approved. In the present study, we examined the feasibility of L-fMRI at 3T using NORDIC denoising. Methods: 5 healthy subjects were scanned on a Siemens MAGNETOM Prisma 3T scanner. To assess across-session reliability, each subject was scanned in 3-8 sessions on 3-4 consecutive days. A 3D gradient echo EPI (GE-EPI) sequence was used for BOLD acquisitions (voxel size 0.82 mm isotopic, TR = 2.2 s) using a block designed finger tapping paradigm. NORDIC denoising was applied to the magnitude and phase time series to overcome limitations in tSNR and the denoised phase time series were subsequently used to correct for large vein contamination through phase regression. Results and conclusion: NORDIC denoising resulted in temporal signal-to-noise ratio (tSNR) values comparable to or higher than commonly observed at 7T. Layer-dependent activation profiles could thus be extracted robustly, within and across sessions, from regions of interest located in the hand knob of the primary motor cortex (M1). Phase regression led to substantially reduced superficial bias in obtained layer profiles, although residual macrovascular contribution remained. We believe the present results support the feasibility of L-fMRI at 3T, which might help make L-fMRI available to a much wider community.

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Section: Specificitysupporting

confidence: 68%

Section: Specificitymentioning

confidence: 93%

Section: Roi Definition and Segmentationmentioning

confidence: 99%

Section: Roi Definition and Segmentationmentioning

confidence: 99%

Section: Roi Definition and Segmentationmentioning

confidence: 99%

See 3 more Smart Citations

Feasibility of 3T layer-dependent fMRI with GE-BOLD using NORDIC and phase regression

Knudsen

Bailey

Blicher

et al. 2022

Preprint

Self Cite

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Contrast Agent‐Free 3D Renal Ultrafast Doppler Imaging Reveals Vascular Dysfunction in Acute and Diabetic Kidney Diseases

Oh,

Lee,

Heo

et al. 2023

Advanced Science

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To combat the irreversible decline in renal function associated with kidney disease, it is essential to establish non‐invasive biomarkers for assessing renal microcirculation. However, the limited resolution and/or vascular sensitivity of existing diagnostic imaging techniques hinders the visualization of complex cortical vessels. Here, a 3D renal ultrafast Doppler (UFD) imaging system that uses a high ultrasound frequency (18 MHz) and ultrahigh frame rate (1 KHz per slice) to scan the entire volume of a rat's kidney in vivo is demonstrated. The system, which can visualize the full 3D renal vascular branching pyramid at a resolution of 167 µm without any contrast agent, is used to chronically and noninvasively monitor kidneys with acute kidney injury (AKI, 3 days) and diabetic kidney disease (DKD, 8 weeks). Multiparametric UFD analyses (e.g., vessel volume occupancy (VVO), fractional moving blood volume (FMBV), vessel number density (VND), and vessel tortuosity (VT)) describe rapid vascular rarefaction from AKI and long‐term vascular degeneration from DKD, while the renal pathogeneses are validated by in vitro blood serum testing and stained histopathology. This work demonstrates the potential of 3D renal UFD to offer valuable insights into assessing kidney perfusion levels for future research in diabetes and kidney transplantation.

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Submillimeter fMRI Acquisition Techniques for Detection of Laminar and Columnar Level Brain Activation

Yun,

Küppers,

Shah

2023

Magnetic Resonance Imaging

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Since the first demonstration in the early 1990s, functional MRI (fMRI) has emerged as one of the most powerful, noninvasive neuroimaging tools to probe brain functions. Subsequently, fMRI techniques have advanced remarkably, enabling the acquisition of functional signals with a submillimeter voxel size. This innovation has opened the possibility of investigating subcortical neural activities with respect to the cortical depths or cortical columns. For this purpose, numerous previous works have endeavored to design suitable functional contrast mechanisms and dedicated imaging techniques. Depending on the choice of the functional contrast, functional signals can be detected with high sensitivity or with improved spatial specificity to the actual activation site, and the pertaining issues have been discussed in a number of earlier works. This review paper primarily aims to provide an overview of the subcortical fMRI techniques that allow the acquisition of functional signals with a submillimeter resolution. Here, the advantages and disadvantages of the imaging techniques will be described and compared. We also summarize supplementary imaging techniques that assist in the analysis of the subcortical brain activation for more accurate mapping with reduced geometric deformation. This review suggests that there is no single universally accepted method as the gold standard for subcortical fMRI. Instead, the functional contrast and the corresponding readout imaging technique should be carefully determined depending on the purpose of the study. Due to the technical limitations of current fMRI techniques, most subcortical fMRI studies have only targeted partial brain regions. As a future prospect, the spatiotemporal resolution of fMRI will be pushed to satisfy the community's need for a deeper understanding of whole‐brain functions and the underlying connectivity in order to achieve the ultimate goal of a time‐resolved and layer‐specific spatial scale.Evidence Level1Technical EfficacyStage 1

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Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla

Cited by 19 publications

References 88 publications

Feasibility of 3T layer-dependent fMRI with GE-BOLD using NORDIC and phase regression

Feasibility of 3T layer-dependent fMRI with GE-BOLD using NORDIC and phase regression

Contrast Agent‐Free 3D Renal Ultrafast Doppler Imaging Reveals Vascular Dysfunction in Acute and Diabetic Kidney Diseases

Submillimeter fMRI Acquisition Techniques for Detection of Laminar and Columnar Level Brain Activation

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