Noncontrast‐enhanced time‐resolved 4D dynamic intracranial MR angiography at 7T: A feasibility study

Cong, Fengyu; Zhuo, Yan; Yu, Songlin; Zhang, Xianchang; Miao, Xinyuan; An, Jing; Wang, Shuo; Cao, Yong; Zhang, Yan; Song, Hee Kwon; Wang, Danny J.J.; Yan, Lirong

doi:10.1002/jmri.25923

Cited by 19 publications

(14 citation statements)

References 34 publications

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“…All images were scored to determine signal homogeneity, lesion conspicuity, quality of venous signal suppression, and diagnostic confidence. A previously reported 4-point scale was applied 13,14 : 4 ϭ excellent (excellent-quality diagnostic information with a clearly detailed vascular architecture, no artifacts), 3 ϭ good (good-quality diagnostic information with adequate delineation of the vascular architecture, minimal artifacts), 2 ϭ poor (poorquality diagnostic information with ordinary delineation of the vascular architecture, moderate artifacts), and 1 ϭ not visible (almost no signal of the vascular architecture, severe artifacts). The time interval between the qualitative analyses was 4 weeks.…”

Section: Image Analysismentioning

confidence: 99%

Validation of Zero TE–MRA in the Characterization of Cerebrovascular Diseases: A Feasibility Study

Shang

Dou³

et al. 2019

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Zero TE-MRA is less sensitive to field heterogeneity, complex flow, and acquisition noise. This study aimed to prospectively validate the feasibility of zero TE-MRA for cerebrovascular diseases assessment, compared with TOF-MRA. MATERIALS AND METHODS: Seventy patients suspected of having cerebrovascular disorders were recruited. Sound levels were estimated for each MRA subjectively and objectively in different modes. MRA image quality was estimated by 2 neuroradiologists. The degree of stenosis (grades 0-4) and the z-diameter of aneurysms (tiny group Յ3 mm and large group Ͼ3 mm) were measured for further quantitative analysis. CTA was used as the criterion standard. RESULTS: Zero TE-MRA achieved significantly lower subjective perception and objective noise reduction (37.53%). Zero TE-MRA images showed higher signal homogeneity (3.29 Ϯ 0.59 versus 3.04 Ϯ 0.43) and quality of venous signal suppression (3.67 Ϯ 0.47 versus 2.75 Ϯ 0.46). The intermodality agreement was higher for zero TE-MRA than for TOF-MRA (zero TE, 0.90; TOF, 0.81) in the grading of stenosis. Zero TE-MRA had a higher correlation than TOF-MRA (zero TE, 0.84; TOF, 0.74) in the tiny group and a higher consistency with CTA (intraclass correlation coefficient, 0.83; intercept, Ϫ0.5084-1.1794; slope Ϫ0.4952 to Ϫ0.2093) than TOF-MRA (intraclass correlation coefficient, 0.64; intercept, 0.7000-2.6133; slope Ϫ1.0344 to Ϫ0.1923). Zero TE-MRA and TOF-MRA were comparable in the large group. Zero TE-MRA had more accurate details than TOF-MRA of AVM and Moyamoya lesions. CONCLUSIONS: Compared with TOF-MRA, zero TE-MRA achieved more robust performance in depicting cerebrovascular diseases. Therefore, zero TE-MRA was shown to be a promising MRA technique for further routine application in the clinic in patients with cerebrovascular diseases. ABBREVIATIONS: ASL ϭ arterial spin-labeling; AVM ϭ arteriovenous malformation; MRA ϭ magnetic resonance angiography; CTA ϭ computed tomography angiography; CE ϭ contrast-enhanced; TOF ϭ time-of-flight; zTE ϭ zero echo time; MIP ϭ maximum intensity projection; VR ϭ volume rendering; MCA ϭ middle cerebral artery; ICA ϭ internal carotid artery

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Section: Image Analysismentioning

confidence: 99%

Validation of Zero TE–MRA in the Characterization of Cerebrovascular Diseases: A Feasibility Study

Shang

Dou³

et al. 2019

AJNR Am J Neuroradiol

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“…For example, Koktzoglou et al [19,22] and Wu et al [20] have demonstrated the excellent image quality achievable with radial trajectories, although no direct comparison with a matched Cartesian approach was performed. Song et al [21] and Cong et al [23] showed comparable image quality with an accelerated stack-of-stars trajectory combined with a k-space filtering approach compared to a fully sampled Cartesian acquisition. Wu et al [18] also showed the improved timing information obtained from a radial approach compared to a Cartesian method in a digital phantom, although no experimental comparison was performed.…”

Section: Discussionmentioning

confidence: 99%

“…The use of a true 3D radial approach in this study allowed the benefits of radial trajectories to apply in all three dimensions and gave whole-brain coverage within a reasonable scan time. However, particularly when only a reduced field-of-view is of interest, comparison of this approach with a stack-of-stars trajectory [21,23] would be useful in future work, as well as validation in a greater number of subjects.…”

Section: Discussionmentioning

confidence: 99%

“…Undersampled radial readouts are particularly applicable for cerebral angiography because the signal is sparse, so streak artifacts are minimal and often relegated to the image periphery [16,17]. Radial trajectories also result in more manageable flow or respiration artifacts than Cartesian acquisitions [15], can give more accurate timing information [18], and have previously been used with success for 3D non-vessel-selective ASL angiography [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

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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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“…By applying these modified techniques, 4D SNAP‐MRA can be further accelerated and improved. The accuracy of hemodynamic information provided by 4D SNAP‐MRA will be validated by experiments on a well‐designed flow‐phantom and patients and compared with the existing arterial spin labeling‐based dynamic MRA techniques in future work.…”

Section: Discussionmentioning

confidence: 99%

Intracranial simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) MRA: Analyzation, optimization, and extension for dynamic MRA

Xiong

Zhang

et al. 2019

Magnetic Resonance in Med

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Purpose: Simultaneous noncontrast angiography and intraplaque (SNAP) imaging, as a noncontrast-enhanced MRA technique, may not provide consistent vessel visualization for intracranial artery imaging among subjects. This study aims to investigate the underlying mechanism and extend SNAP to dynamic MRA. Methods: The cause of the instability of intracranial SNAP-MRA was investigated through theoretical analysis and simulations. The scan parameters, including TI and flip angle, were optimized for reliable imaging. In vivo experiments were conducted to validate the simulation results. The simulation results were correlated with real intracranial blood flow by introducing the concept of blood travel time, and intracranial SNAP-MRA was revealed to reflect the cerebral blood expanse region in 5 TI. A new noncontrast-enhanced dynamic MRA technique, termed 4D SNAP-MRA, was proposed and demonstrated through in vivo scans. Results: The cause of the instability of intracranial SNAP-MRA was proved to be the slow or fast blood flow in the imaging slab. This instability can be mitigated by adjusting TI and flip angle in the SNAP sequence. The proposed 4D SNAP-MRA can provide dynamic visualization of the cerebral blood circulation and cerebral hemodynamic information such as blood travel time. Conclusion: The 3D SNAP-MRA with optimal imaging parameters can generate cerebral angiography with hemodynamic information, and the 4D SNAP-MRA provides dynamic visualization of the cerebral blood circulation. K E Y W O R D S blood travel time, cerebral hemodynamics, dynamic MRA, intracranial MRA, SNAP | 1647 XIONG et al.

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Noncontrast‐enhanced time‐resolved 4D dynamic intracranial MR angiography at 7T: A feasibility study

Abstract: 2 Technical Efficacy Stage 2 J. Magn. Reson. Imaging 2017.

Cited by 19 publications

References 34 publications

Validation of Zero TE–MRA in the Characterization of Cerebrovascular Diseases: A Feasibility Study

Validation of Zero TE–MRA in the Characterization of Cerebrovascular Diseases: A Feasibility Study

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

Intracranial simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) MRA: Analyzation, optimization, and extension for dynamic MRA

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