Quantification of intracranial arterial blood flow using noncontrast enhanced 4D dynamic MR angiography

Shao, Xingfeng; Zhao, Ziwei; Russin, Jonathan; Amar, Arun Paul; Sanossian, Nerses; Wang, Danny J.J.; Yan, Lirong

doi:10.1002/mrm.27712

Cited by 10 publications

(11 citation statements)

References 32 publications

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“…Another emerging application of ASL is non-contrast enhanced time-resolved 4D dynamic magnetic resonance angiography (dMRA) [ 4 – 6 ] that provides the depiction of both the architecture of cerebral vasculature with high spatial resolution (mm) and dynamic flow pattern of labeled blood with high temporal resolution (a few hundred ms). Quantitative hemodynamic parameters are also derived from dMRA, such as arterial blood flow (aBF), arterial blood volume (aBV), ATT, and time-to-peak (TTP) [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

k-space weighted image average (KWIA) for ASL-based dynamic MR angiography and perfusion imaging

Zhao

Shao

Yan

et al. 2022

Magnetic Resonance Imaging

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A novel denoising algorithm termed k-space weighted image average (KWIA) was proposed to improve the signal-to-noise ratio (SNR) of dynamic MRI, such as arterial spin labeling (ASL)-based dynamic magnetic resonance angiography (dMRA) and perfusion imaging. KWIA divides the k-space of each time frame into multiple rings, the central ring of the k-space remains intact to preserve the image contrast and temporal resolution, while outer rings are progressively averaged with neighboring time frames to increase SNR. Simulations and in-vivo dMRA and multi-delay ASL studies were performed to evaluate the performance of KWIA under various MRI acquisition conditions. SNR ratios and temporal signal errors between KWIA-processed and the original data were measured. Visualization of dynamic blood flow signals as well as quantitative parametric maps were evaluated for KWIA-processed images as compared to the original images. KWIA achieved a SNR ratio of 1.73 for dMRA and 2.0 for multi-delay ASL respectively, which were in accordance with the theoretical predictions. Improved visualization of dynamic blood flow signals was demonstrated using KWIA in distal small vessels in dMRA and small brain structures in multi-delay ASL. Approximately 5% temporal errors were observed in both KWIA-processed dMRA and ASL signals. Fine anatomical features were revealed in the quantitative parametric maps of dMRA, and the residuals of model fitting were reduced for multi-delay ASL. Compared to other conventional denoising methods, KWIA is a flexible denoising algorithm that improves the SNR of ASL-based dMRA and perfusion MRI by up to 2-fold without compromising spatial and temporal resolution or quantification accuracy.

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Section: Introductionmentioning

confidence: 99%

k-space weighted image average (KWIA) for ASL-based dynamic MR angiography and perfusion imaging

Zhao

Shao

Yan

et al. 2022

Magnetic Resonance Imaging

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“…The voxel‐wise arterial arrival time (AAT) of the intracranial vessels was quantified as the first time point at which the 4D MRA signal was greater than 3× standard deviation of the background noise 34 . Territorial segmentation of cerebroarterial vessels was carried out using an iterative AAT‐based region‐growing algorithm similar to that proposed by Geri et al 5 The implemented algorithm is shown schematically in Figure 1E and is briefly described below:…”

Section: Methodsmentioning

confidence: 99%

Semiautomatic cerebrovascular territory mapping based on dynamic ASL MR angiography without vessel‐encoded labeling

Pahlavian

Geri²,

Russin

et al. 2020

Magnetic Resonance in Med

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Characterizing vessel territories can provide crucial information for evaluation of cerebrovascular disorders. In this study, we present a novel postprocessing pipeline for vascular territorial imaging of cerebral arteries based on a noncontrast enhanced time-resolved 4D magnetic resonance angiography (MRA). Methods: Eight healthy participants, 1 Moyamoya patient, and 1 arteriovenous malformations patient were recruited. Territorial segmentation and relative blood flow rate calculations of cerebral arteries including left and right middle cerebral arteries and left and right posterior cerebral arteries were carried out based on the 4D MRAderived arterial arrival time maps of intracranial vessels. Results: Among healthy young subjects, the average relative blood flow rate values corresponding to left and right middle cerebral arteries and left and right posterior cerebral arteries were 35.9 ± 5.9%, 32.9 ± 7.5%, 15.4 ± 3.8%, and 15.9 ± 2.5%, respectively. Excellent agreement was observed between relative blood flow rate values obtained from the proposed 4D MRA-based method and reference 2D phase contrast MRI. Abnormal cerebral circulations were visualized and quantified on both patients using the developed technique. Conclusion: The vascular territorial imaging technique developed in this study allowed for the generation of territorial maps with user-defined level of details within a clinically feasible scan time, and as such may provide useful information to assess cerebral circulation balance in different pathologies.

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“…Although the ideal spatial resolution has not been standardized yet, the voxel-sizes from previous studies are typically 1.0-1.25 mm in in-plane and 1.0-2.0 mm in through-plane direction (potentially reconstructed at even higher resolution). 1,4,[22][23][24] Therefore, the entire scan-time usually needs to be spent for completing k-space, not for signal averaging as in perfusion imaging. The typical readout sequence used for ASL-MRA is based on gradient-echo sequences, such as turbo field-echo (TFE) 2,3 and spoiled gradient-echo (SPGR), [24][25][26][27] in which quite a number of excitation RF-pulses are applied.…”

Section: Spatial Resolution and Readout Sequencementioning

confidence: 99%

Intracranial 3D and 4D MR Angiography Using Arterial Spin Labeling: Technical Considerations

Suzuki

Fujima

Osch

2020

MRMS

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In the 1980's some of the earliest studies of arterial spin labeling (ASL) MRI have demonstrated its ability to generate MR angiography (MRA) images. Thanks to many technical improvements, ASL has been successfully moving its position from the realm of research into the clinical area, albeit more known as perfusion imaging than as MRA. For MRA imaging, other techniques such as time-of-flight, phase contrast MRA and contrast-enhanced (CE) MRA are more popular choices for clinical applications. In the last decade, however, ASL-MRA has been experiencing a remarkable revival, especially because of its non-invasive nature, i.e. the fact that it does not rely on the use of contrast agent. Very importantly, there are additional benefits of using ASL for MRA. For example, its higher flexibility to achieve both high spatial and temporal resolution than CE dynamic MRA, and the capability of vessel specific visualization, in which the vascular tree arising from a selected artery can be exclusively visualized. In this article, the implementation and recent developments of ASL-based MRA are discussed; not only focusing on the basic sequences based upon pulsed ASL or pseudo-continuous ASL, but also including more recent labeling approaches, such as vessel-selective labeling, velocity-selective ASL, vessel-encoded ASL and time-encoded ASL. Although these ASL techniques have been already utilized in perfusion imaging and their usefulness has been suggested by many studies, some additional considerations should be made when employing them for MRA, since there is something more than the difference of the spatial resolution of the readout sequence. Moreover, extensive discussion is included on what readout sequence to use, especially by highlighting how to achieve high spatial resolution while keeping scan-time reasonable such that the ASL-MRA sequence can easily be included into a clinical examination.

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Quantification of intracranial arterial blood flow using noncontrast enhanced 4D dynamic MR angiography

Cited by 10 publications

References 32 publications

k-space weighted image average (KWIA) for ASL-based dynamic MR angiography and perfusion imaging

k-space weighted image average (KWIA) for ASL-based dynamic MR angiography and perfusion imaging

Semiautomatic cerebrovascular territory mapping based on dynamic ASL MR angiography without vessel‐encoded labeling

Intracranial 3D and 4D MR Angiography Using Arterial Spin Labeling: Technical Considerations

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