Improved sensitivity and temporal resolution in perfusion FMRI using velocity selective inversion ASL

Hernandez‐García, Luis; Nielsen, Jon‐Fredrik; Noll, Douglas C.

doi:10.1002/mrm.27461

Cited by 22 publications

(46 citation statements)

References 30 publications

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“…VS pulses also allow for faster repetition times and are thus beneficial for perfusion-based functional MRI. 16,18 Velocity-selective pulses fit into 2 categories: VS saturation pulses (VSS) and VS Inversion (VSI) pulses. VSS pulses tip the magnetization into the transverse plane briefly before tipping it back to the longitudinal axis.…”

Section: Introductionmentioning

confidence: 99%

Comparison of velocity‐selective arterial spin labeling schemes

Guo

Das

Hernandez‐García

2020

Magnetic Resonance in Med

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In velocity-selective (VS) arterial spin labeling, strategies using multiple saturation modules or using VS inversion (VSI) pulse can provide improved SNR efficiency compared to the original labeling scheme using one VS saturation (VSS) module. Their performance improvement, however, has not been directly compared. Methods: Different VS labeling schemes were evaluated by Bloch simulation for their SNR efficiency, eddy current sensitivity, and robustness against B 1 and B 0 variation. These schemes included dual-module double-refocused hyperbolic secant and symmetric 8-segment B 1-insensitive rotation (sBIR8-) VSS pulses, the original and modified Fourier transform-based VSI pulses. A subset of the labeling schemes was examined further in phantom and in vivo experiments for their eddy current sensitivity and SNR performance. An additional sBIR8-VSS with a built-in inversion (sBIR8-VSS-inversion) was evaluated for the effects of partial background suppression to allow a fairer comparison to VSI. Results: According to the simulations, the sBIR8-VSS was the most robust against field imperfections and had similarly high SNR efficiency (dual-module, dual-sBIR8-VSS) compared with the best VSI pulse (sinc-modulated, sinc-VSI). These were confirmed by the phantom and in vivo data. Without additional background suppression, the sinc-VSI pulses had the highest temporal SNR, closely followed by the sBIR8-VSS-inversion pulse, both benefited from partial background suppression effects. Conclusion: Dual-sBIR8-VSS and sinc-VSI measured the highest SNR efficiency among the VS labeling schemes. Dual-sBIR8-VSS was the most robust against field imperfections, whereas sinc-VSI may provide a higher SNR efficiency if its immunity to field imperfections can be improved.

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Section: Introductionmentioning

confidence: 99%

Comparison of velocity‐selective arterial spin labeling schemes

Guo

Das

Hernandez‐García

2020

Magnetic Resonance in Med

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“…The use of image background suppression (BGS) pulses to reduce unwanted image components, such as noise and motion artifacts, was proposed, e.g., by Garcia et al [89] and Alsop et al [90]. However, its contribution to an improvement of ASL quantification is currently debated [4].…”

Section: Arterial Spin Labelingmentioning

confidence: 99%

Image registration in dynamic renal MRI—current status and prospects

Zöllner

Serifovic-Trbalic

Kabelitz

et al. 2019

Magn Reson Mater Phy

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Magnetic resonance imaging (MRI) modalities have achieved an increasingly important role in the clinical work-up of chronic kidney diseases (CKD). This comprises among others assessment of hemodynamic parameters by arterial spin labeling (ASL) or dynamic contrast-enhanced (DCE-) MRI. Especially in the latter, images or volumes of the kidney are acquired over time for up to several minutes. Therefore, they are hampered by motion, e.g., by pulsation, peristaltic, or breathing motion. This motion can hinder subsequent image analysis to estimate hemodynamic parameters like renal blood flow or glomerular filtration rate (GFR). To overcome motion artifacts in time-resolved renal MRI, a wide range of strategies have been proposed. Renal image registration approaches could be grouped into (1) image acquisition techniques, (2) post-processing methods, or (3) a combination of image acquisition and post-processing approaches. Despite decades of progress, the translation in clinical practice is still missing. The aim of the present article is to discuss the existing literature on renal image registration techniques and show today’s limitations of the proposed techniques that hinder clinical translation. This paper includes transformation, criterion function, and search types as traditional components and emerging registration technologies based on deep learning. The current trend points towards faster registrations and more accurate results. However, a standardized evaluation of image registration in renal MRI is still missing.

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“…Segmented 3D gradient‐ and spin‐echo (GRASE) acquisition with whole‐brain coverage is one of the recommended imaging methods in the standardized ASL protocol for clinical translation 1 . Recently, FT‐VSI with low‐flip‐angle segmented 3D stack‐of‐spirals and without using background suppression pulses was performed at multiple PLDs to characterize the tracer kinetics of the VSI labeling and used for perfusion‐based functional MRI 22 …”

Section: Introductionmentioning

confidence: 99%

Improved velocity‐selective‐inversion arterial spin labeling for cerebral blood flow mapping with 3D acquisition

Liu

et al. 2020

Magnetic Resonance in Med

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Purpose To further optimize the velocity‐selective arterial spin labeling (VSASL) sequence utilizing a Fourier‐transform based velocity‐selective inversion (FT‐VSI) pulse train, and to evaluate its utility for 3D mapping of cerebral blood flow (CBF) with a gradient‐ and spin‐echo (GRASE) readout. Methods First, numerical simulations and phantom experiments were done to test the susceptibility to eddy currents and B1 field inhomogeneities for FT‐VSI pulse trains with block and composite refocusing pulses. Second, the choices of the post‐labeling delay (PLD) for FT‐VSI prepared 3D VSASL were evaluated for the sensitivity to perfusion signal. The study was conducted among a young‐age and a middle‐age group at 3T. Both signal‐to‐noise ratio (SNR) and CBF were quantitatively compared with pseudo‐continuous ASL (PCASL). The optimized 3D VSI‐ASL was also qualitatively compared with PCASL in a whole‐brain coverage among two healthy volunteers and a brain tumor patient. Results The simulations and phantom test showed that composite refocusing pulses are more robust to both eddy‐currents and B1 field inhomogeneities than block pulses. 3D VSASL images with FT‐VSI preparation were acquired over a range of PLDs and PLD = 1.2 s was selected for its higher perfusion signal. FT‐VSI labeling produced quantitative CBF maps with 27% higher SNR in gray matter compared to PCASL. 3D whole‐brain CBF mapping using VSI‐ASL were comparable to the corresponding PCASL results. Conclusion FT‐VSI with 3D‐GRASE readout was successfully implemented and showed higher sensitivity to perfusion signal than PCASL for both young and middle‐aged healthy volunteers.

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Improved sensitivity and temporal resolution in perfusion FMRI using velocity selective inversion ASL

Abstract: VSI pulses can be very beneficial for perfusion weighted functional MRI because of their tracer kinetic characteristics, which allow a faster acquisition rate while maintaining an efficient labeling input function.

Cited by 22 publications

References 30 publications

Comparison of velocity‐selective arterial spin labeling schemes

Comparison of velocity‐selective arterial spin labeling schemes

Image registration in dynamic renal MRI—current status and prospects

Improved velocity‐selective‐inversion arterial spin labeling for cerebral blood flow mapping with 3D acquisition

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