Robust single-shot acquisition of high resolution whole brain ASL images by combining time-dependent 2D CAPIRINHA sampling with spatio-temporal TGV reconstruction

Spann, Stefan Manfred; Shao, Xingfeng; Wang, Danny J.J.; Aigner, Christoph Stefan; Schlöegl, Matthias; Bredies, Kristian; Stollberger, Rudolf

doi:10.1016/j.neuroimage.2019.116337

Cited by 31 publications

(46 citation statements)

References 49 publications

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“…Both imaging coverage and temporal resolution of the proposed technique can be further improved by utilizing accelerated image acquisition and constrained reconstructions (52,53). It is also feasible to perform perfusion based functional connectivity analysis of brain network dynamics with increased coverage and temporal resolution (54).…”

Section: Discussionmentioning

confidence: 99%

Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla

Shao

Guo

Shou

et al. 2021

Preprint

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Laminar fMRI based on BOLD and CBV contrast at ultrahigh magnetic fields has been applied for studying the dynamics of mesoscopic brain networks. However, the quantitative interpretations of BOLD/CBV fMRI results are confounded by different baseline physiology across cortical layers. Here we introduce a novel 3D zoomed pseudo-continuous arterial spin labeling technique at 7T that offers the unique capability for quantitative measurements of laminar cerebral blood flow (CBF) both at rest and during task activation with high spatial specificity and sensitivity. We found arterial transit time in superficial layers is ~100 msec shorter than in middle/deep layers revealing the dynamics of labeled blood flowing from pial arteries to downstream microvasculature. Resting state CBF peaked in the middle layers which is highly consistent with microvascular density measured from human cortex specimens. Finger tapping induced a robust two-peak laminar profile of CBF increases in the superficial (somatosensory and premotor input) and deep (spinal output) layers of M1, while finger brushing task induced a weaker CBF increase in superficial layers (somatosensory input). We further demonstrated that top-down attention induced a predominant CBF increase in deep layers and a smaller CBF increase on top of the lower baseline CBF in superficial layers of V1 (feedback cortical input), while bottom-up stimulus driven activity peaked in the middle layers (feedforward thalamic input). These quantitative laminar profiles of perfusion activity suggest an important role of M1 superficial layers for the computation of finger movements, and that visual attention may amplify deep layer output to the subcortex.

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Section: Discussionmentioning

confidence: 99%

Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla

Shao

Guo

Shou

et al. 2021

Preprint

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“…The differentiation between the two compartment is reliable given the large diffusion coefficient difference (∼100-fold) between the intra-and extravascular compartments (Shao et al, 2019). kw map was calculated by a total-generalized-variation (TGV) (Spann et al, 2020) regularized single-pass-approximation (SPA) model (St Lawrence et al, 2012) using the tissue (or capillary) fraction of the ASL signal at the PLD of 1,800 ms, incorporating ATT, T1 of arterial blood [1.66 s (Lu et al, 2004)] and brain tissue as inputs for the algorithm (Shao et al, 2019). Voxel-wise tissue T1 map was fitted from background suppressed control images acquired at 2 PLDs .…”

Section: Discussionmentioning

confidence: 99%

“…WM masks were also eroded to avoid partial volume effect between CSF or GM. To improve the spatial resolution and sensitivity to detect kw changes in small ROIs, accelerated single-shot GRASE sequence and spatio-temporal regularized reconstruction might be utilized (Spann et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Comparison Between Blood-Brain Barrier Water Exchange Rate and Permeability to Gadolinium-Based Contrast Agent in an Elderly Cohort

et al. 2020

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Background: Dynamic contrast-enhanced (DCE) MRI using intravenous injection of gadolinium-based contrast agents (GBCAs) is commonly used for imaging blood-brain barrier (BBB) permeability. Water is an alternative endogenous tracer with limited exchange rate across the BBB. A direct comparison between BBB water exchange rate and BBB permeability to GBCA is missing. The purpose of this study was to directly compare BBB permeability to GBCA (Ktrans and kGad = Ktrans/Vp) and water exchange rate (kw) in a cohort of elderly subjects at risk of cerebral small vessel disease (cSVD).Methods: Ktrans/kGad and kw were measured by DCE-MRI and diffusion prepared pseudo-continuous arterial spin labeling (DP-pCASL), respectively, at 3 Tesla in 16 elderly subjects (3 male, age = 67.9 ± 3.0 yrs) at risk of cSVD. The test-retest reproducibility of kw measurements was evaluated with repeated scans ~6 weeks apart. Mixed effects linear regression was performed in the whole brain, gray matter (GM), white matter (WM), and 6 subcortical brain regions to investigate associations between Ktrans/kGad and test-retest kw. In addition, kw and Ktrans/kGad were compared in normal appearing white matter (NAWM), white matter hyperintensity (WMH) lesions and penumbra.Results: Significant correlation was found between kw and Ktrans only in WM (β = 6.7 × 104, P = 0.036), caudate (β = 8.6 × 104, P = 0.029), and middle cerebral artery (MCA) perforator territory (β = 6.9 × 104, P = 0.009), but not in the whole brain, GM or rest 5 brain regions. Significant correlation was found between kw and kGad in MCA perforator territory (β = 1.5 × 103, P = 0.049), medial-temporal lobe (β = 3.5 × 103, P = 0.032), and hippocampus (β = 3.4 × 103, P = 0.038), but not in the rest brain regions. Good reproducibility of kw measurements (ICC=0.75) was achieved. Ktrans was significantly lower inside WMH than WMH penumbra (16.2%, P = 0.026), and kGad was significantly lower in NAWM than in the WMH penumbra (20.8%, P < 0.001).Conclusion: kw provides a measure of water exchange rate across the BBB with good test-retest reproducibility. The BBB mechanism underlying kw and Ktrans/kGad is likely to be different, as manifested by correlations in only three brain regions for each pair of comparison between kw and Ktrans or kGad.

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“…For DP‐pCASL, the tissue and capillary compartments of the ASL signal were separated by a small diffusion gradient of 50 s/mm 2 . The k w map was calculated by a total‐generalized‐variation (TGV) 27 regularized SPA model 17 using the tissue (or capillary) fraction of the ASL signal at the PLD of 1800 ms, incorporating ATT, T1 of arterial blood and brain tissue as inputs for the algorithm 18 . Arterial blood T1 was assumed to be 1.66 s, which is commonly used for CBF quantification 28 .…”

Section: Methodsmentioning

confidence: 99%

Water exchange rate across the blood‐brain barrier is associated with CSF amyloid‐β 42 in healthy older adults

Gold

Shao

Sudduth

et al. 2021

Alzheimer's & Dementia

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Introduction We tested if water exchange across the blood‐brain barrier (BBB), estimated with a noninvasive magnetic resonance imaging (MRI) technique, is associated with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) and neuropsychological function. Methods Forty cognitively normal older adults (67–86 years old) were scanned with diffusion‐prepared, arterial spin labeling (DP‐ASL), which estimates water exchange rate across the BBB (kw). Participants also underwent CSF draw and neuropsychological testing. Multiple linear regression models were run with kw as a predictor of CSF concentrations and neuropsychological scores. Results In multiple brain regions, BBB kw was positively associated with CSF amyloid beta (Aβ)42 concentration levels. BBB kw was only moderately associated with neuropsychological performance. Discussion Our results suggest that low water exchange rate across the BBB is associated with low CSF Aβ42 concentration. These findings suggest that kw may be a promising noninvasive indicator of BBB Aβ clearance functions, a possibility which should be further tested in future research.

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Robust single-shot acquisition of high resolution whole brain ASL images by combining time-dependent 2D CAPIRINHA sampling with spatio-temporal TGV reconstruction

Cited by 31 publications

References 49 publications

Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla

Laminar perfusion imaging with zoomed arterial spin labeling at 7 Tesla

Comparison Between Blood-Brain Barrier Water Exchange Rate and Permeability to Gadolinium-Based Contrast Agent in an Elderly Cohort

Water exchange rate across the blood‐brain barrier is associated with CSF amyloid‐β 42 in healthy older adults

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