3D time-resolved vessel-selective angiography based on pseudo-continuous arterial spin labeling

Lindner, Thomas; Jensen‐Kondering, Ulf; Osch, Matthias J.P. van; Jansen, Olav; Helle, Michael

doi:10.1016/j.mri.2015.03.001

Cited by 19 publications

(19 citation statements)

References 35 publications

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“…Arterial spin labeling (ASL) is capable of generating angiographic contrast through the subtraction of images acquired with and without the prior inversion of blood magnetization flowing into the imaging region , negating the need for an exogenous contrast agent. Many recent studies have used spoiled gradient echo (SPGR) readouts, for example References , but one drawback of this approach is that SPGR significantly attenuates the ASL contrast: every repetition time ( T R ) a fraction (1 – cos α ) of the remaining longitudinal magnetization is lost , where α is the excitation flip angle. In order to preserve sufficient signal the flip angle and T R used for imaging are therefore highly restricted, particularly when a long readout period is required, limiting the achievable signal‐to‐noise ratio (SNR) and increasing the scan time.…”

Section: Introductionmentioning

confidence: 99%

“…For vessel-selective applications, the ASL preparation can be modified to label blood flowing through an individual artery (12,14,25,26). However, such methods are not SNR efficient where multiple arteries are of interest, since labeled blood signal is confined to a single artery on any given acquisition: for example, to generate four vessel-selective angiograms of the brainfeeding arteries, the measured signal y can be described using the equations of Wong (27) as…”

Section: Introductionmentioning

confidence: 99%

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Optimization of 4D vessel‐selective arterial spin labeling angiography using balanced steady‐state free precession and vessel‐encoding

Okell

Schmitt

et al. 2016

NMR Biomed.

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Vessel‐selective dynamic angiograms provide a wealth of useful information about the anatomical and functional status of arteries, including information about collateral flow and blood supply to lesions. Conventional x‐ray techniques are invasive and carry some risks to the patient, so non‐invasive alternatives are desirable. Previously, non‐contrast dynamic MRI angiograms based on arterial spin labeling (ASL) have been demonstrated using both spoiled gradient echo (SPGR) and balanced steady‐state free precession (bSSFP) readout modules, but no direct comparison has been made, and bSSFP optimization over a long readout period has not been fully explored. In this study bSSFP and SPGR are theoretically and experimentally compared for dynamic ASL angiography. Unlike SPGR, bSSFP was found to have a very low ASL signal attenuation rate, even when a relatively large flip angle and short repetition time were used, leading to a threefold improvement in the measured signal‐to‐noise ratio (SNR) efficiency compared with SPGR. For vessel‐selective applications, SNR efficiency can be further improved over single‐artery labeling methods by using a vessel‐encoded pseudo‐continuous ASL (VEPCASL) approach. The combination of a VEPCASL preparation with a time‐resolved bSSFP readout allowed the generation of four‐dimensional (4D; time‐resolved three‐dimensional, 3D) vessel‐selective cerebral angiograms in healthy volunteers with 59 ms temporal resolution. Good quality 4D angiograms were obtained in all subjects, providing comparable structural information to 3D time‐of‐flight images, as well as dynamic information and vessel selectivity, which was shown to be high. A rapid 1.5 min dynamic two‐dimensional version of the sequence yielded similar image features and would be suitable for a busy clinical protocol. Preliminary experiments with bSSFP that included the extracranial vessels showed signal loss in regions of poor magnetic field homogeneity. However, for intracranial vessel‐selective angiography, the proposed bSSFP VEPCASL sequence is highly SNR efficient and could provide useful information in a range of cerebrovascular diseases. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of 4D vessel‐selective arterial spin labeling angiography using balanced steady‐state free precession and vessel‐encoding

Okell

Schmitt

et al. 2016

NMR Biomed.

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“…Time-resolved angiography methods would make it possible to visualize and measure the arterial transit times of the blood in an AVM and allow adapting the labeling duration accordingly. Such MR based approaches have already been proposed, but the selectivity of the labeling of such methods is restricted to larger vessels and acquisition times may increase with concurrent increase of spatial and time resolution [19,20,[32][33][34][35][36]. As opposed to DSA, MR based methods generally allow for the acquisition of different image contrasts and with identical location of the image stacks.…”

Section: Fig 3 Depiction Of Intracranial Arteriesmentioning

confidence: 99%

Superselective pseudo-continuous arterial spin labeling angiography

Jensen‐Kondering

Lindner

Osch

et al. 2015

European Journal of Radiology

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“…However, the current clinical gold standard, X-ray digital subtraction angiography, requires the use of an invasive procedure and injection of a contrast agent, resulting in some risks to the patient [1]. Non-invasive alternatives, based on arterial spin labeling (ASL) MRI, show promise, but may be prohibitively slow for many clinical settings because additional measurements are required to obtain vessel-selective information from multiple arteries [2][3][4][5][6]. The investigation of accelerated vesselselective ASL methods is, therefore, warranted, since these could allow phenomena such as occlusions, stenoses, collateral flow and blood supply to lesions to be visualized noninvasively within a clinically acceptable time frame.…”

Section: Introductionmentioning

confidence: 99%

The advantages of radial trajectories for vessel-selective dynamic angiography with arterial spin labeling

Esk.

Jezzard

Okell

2019

Magn Reson Mater Phy

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Objectives To demonstrate the advantages of radial k-space trajectories over conventional Cartesian approaches for accelerating the acquisition of vessel-selective arterial spin labeling (ASL) dynamic angiograms, which are conventionally time consuming to acquire. Materials and methods Vessel-encoded pseudocontinuous ASL was combined with time-resolved balanced steady-state free precession (bSSFP) and spoiled gradient echo (SPGR) readouts to obtain dynamic vessel-selective angiograms arising from the four main brain-feeding arteries. Dynamic 2D protocols with acquisition times of one minute or less were achieved through radial undersampling or a Cartesian parallel imaging approach. For whole-brain dynamic 3D imaging, magnetic field inhomogeneity and the high acceleration factors required rule out the use of bSSFP and Cartesian trajectories, so the feasibility of acquiring 3D radial SPGR angiograms was tested. Results The improved SNR efficiency of bSSFP over SPGR was confirmed for 2D dynamic imaging. Radial trajectories had considerable advantages over a Cartesian approach, including a factor of two improvements in the measured SNR (p < 0.00001, N = 6), improved distal vessel delineation and the lack of a need for calibration data. The 3D radial approach produced good quality angiograms with negligible artifacts despite the high acceleration factor (R = 13). Conclusion Radial trajectories outperform conventional Cartesian techniques for accelerated vessel-selective ASL dynamic angiography.

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3D time-resolved vessel-selective angiography based on pseudo-continuous arterial spin labeling

Cited by 19 publications

References 35 publications

Optimization of 4D vessel‐selective arterial spin labeling angiography using balanced steady‐state free precession and vessel‐encoding

Optimization of 4D vessel‐selective arterial spin labeling angiography using balanced steady‐state free precession and vessel‐encoding

Superselective pseudo-continuous arterial spin labeling angiography

The advantages of radial trajectories for vessel-selective dynamic angiography with arterial spin labeling

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