Contrast‐enhanced intracranial magnetic resonance angiography with a spherical shells trajectory and online gridding reconstruction

Shu, Yunhong; Bernstein, Matt A.; Huston, John; Rettmann, Dan

doi:10.1002/jmri.21938

Cited by 6 publications

(11 citation statements)

References 26 publications

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“…The acquisition strategy proposed for MP-Shells can potentially be extended to different MR acquisitions such as contrast enhanced MR angiography (10,48), double inversion recovery (49), or other applications requiring imaging of dynamically changing contrast. In the case of double inversion recovery, the acquisition of the inner k-space shells can be synchronized with the time point when both CSF and white matter are attenuated as desired.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, the ordering of the shells sampling as a function of the radius can be flexibly arranged to adapt to specific applications. For contrast-enhanced MR angiography, the acquisition of the central shells in k-space can be synchronized to the arrival of the first pass of a contrast agent at the artery of interest, suppressing venous phase signal, as demonstrated previously in the intracranial venous suppressed contrast-enhanced MR angiography (10).…”

Section: Introductionmentioning

confidence: 99%

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Magnetization‐prepared shells trajectory with automated gradient waveform design

Shu

Tao

Trzasko

et al. 2017

Magnetic Resonance in Med

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetization‐prepared shells trajectory with automated gradient waveform design

Shu

Tao

Trzasko

et al. 2017

Magnetic Resonance in Med

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“…The proposed gradient pre‐emphasis method can potentially benefit any MR data acquisition performed on the asymmetric gradient system. This method may be particularly helpful for imaging 3D volumes acquired for arterial spin labeling applications that use stacks of spiral acquisitions , 3D radial acquisition , and shells with integrated radial and spiral . Note that Equation predicts that the effects of the first‐order concomitant fields will increase as the imaging region is displaced further from the gradient isocenter, highlighting the importance of its compensation.…”

Section: Discussionmentioning

confidence: 99%

Gradient pre-emphasis to counteract first-order concomitant fields on asymmetric MRI gradient systems

et al. 2016

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PURPOSE To develop a gradient pre-emphasis scheme that prospectively counteracts the effects of the first-order concomitant fields for any arbitrary gradient waveform played on asymmetric gradient systems, and to demonstrate the effectiveness of this approach using a real-time implementation on a compact gradient system. METHODS After reviewing the first-order concomitant fields that are present on asymmetric gradients, a generalized gradient pre-emphasis model assuming arbitrary gradient waveforms is developed to counteract their effects. A numerically straightforward, simple to implement approximate solution to this pre-emphasis problem is derived, which is compatible with the current hardware infrastructure used on conventional MRI scanners for eddy current compensation. The proposed method was implemented on the gradient driver sub-system, and its real-time use was tested using a series of phantom and in vivo data acquired from 2D Cartesian phase-difference, echo-planar imaging (EPI) and spiral acquisitions. RESULTS The phantom and in vivo results demonstrate that unless accounted for, first-order concomitant fields introduce considerable phase estimation error into the measured data and result in images exhibiting spatially dependent blurring/distortion. The resulting artifacts are effectively prevented using the proposed gradient pre-emphasis. CONCLUSION An efficient and effective gradient pre-emphasis framework is developed to counteract the effects of first-order concomitant fields of asymmetric gradient systems.

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“…A static cylindrical phantom with resolution bars 15 was scanned on a 3 T scanner (General Electric, Signa HDxt, v16.0) using the zoom mode gradient [maximum gradient amplitude 40 mT/m; slew rate 200 (T/m)/s] and a singlechannel T/R head coil. The phantom was translated to 84 mm in gradient inferior direction to observe a relatively strong GNL effect, and scanned with a 2D Archimedean spiral sequence (FOV = 22 cm, slice thickness = 3 mm, acquisition plane = axial, T R = 100 ms, BW = ±62.5 kHz, F A = 30…”

Section: B Experimentsmentioning

confidence: 99%

“…[12][13][14] In the case of nonCartesian MRI, the image blurring effect is further complicated by the presence of main magnetic field (B 0 ) inhomogeneity and susceptibility. 15,16 Recently, a model-based reconstruction framework for Cartesian MRI that performed GNL correction duringrather than after-image reconstruction was developed. 13 This integrated GNL correction method was shown to be able to alleviate the image blurring and resolution loss introduced by the standard GNL correction.…”

Section: Introductionmentioning

confidence: 99%

NonCartesian MR image reconstruction with integrated gradient nonlinearity correction

Tao¹,

Trzasko²,

Shu³

et al. 2015

Medical Physics

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Purpose: To derive a noniterative gridding-type reconstruction framework for nonCartesian magnetic resonance imaging (MRI) that prospectively accounts for gradient nonlinearity (GNL)-induced image geometrical distortion during MR image reconstruction, as opposed to the standard, image-domain based GNL correction that is applied after reconstruction; to demonstrate that such framework is able to reduce the image blurring introduced by the conventional GNL correction, while still offering effective correction of GNL-induced geometrical distortion and compatibility with off-resonance correction. Methods: After introducing the nonCartesian MRI signal model that explicitly accounts for the effects of GNL and off-resonance, a noniterative gridding-type reconstruction framework with integrated GNL correction based on the type-III nonuniform fast Fourier transform (NUFFT) is derived. A novel type-III NUFFT implementation is then proposed as a numerically efficient solution to the proposed framework. The incorporation of simultaneous B 0 off-resonance correction to the proposed framework is then discussed. Several phantom and in vivo data acquired via various 2D and 3D nonCartesian acquisitions, including 2D Archimedean spiral, 3D shells with integrated radial and spiral, and 3D radial sampling, are used to compare the results of the proposed and the standard GNL correction methods. Results: Various phantom and in vivo data demonstrate that both the proposed and the standard GNL correction methods are able to correct the coarse-scale geometric distortion and blurring induced by GNL and off-resonance. However, the standard GNL correction method also introduces blurring effects to corrected images, causing blurring of resolution inserts in the phantom images and loss of small vessel clarity in the angiography examples. On the other hand, the results after the proposed GNL correction show better depiction of resolution inserts and higher clarity of small vessel. Conclusions: The proposed GNL-integrated nonCartesian reconstruction method can mitigate the resolution loss that occurs during standard image-domain GNL correction, while still providing effective correction of coarse-scale geometric distortion and blurring induced by GNL and off-resonance. C 2015 American Association of Physicists in Medicine. [http://dx

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Contrast‐enhanced intracranial magnetic resonance angiography with a spherical shells trajectory and online gridding reconstruction

Abstract: It was demonstrated that the use of the shells trajectory is feasible in a clinical setting to acquire intracranial angiograms with high spatial resolution. Preliminary results demonstrate effective venous suppression in the cavernous sinuses and jugular vein region.

Cited by 6 publications

References 26 publications

Magnetization‐prepared shells trajectory with automated gradient waveform design

Magnetization‐prepared shells trajectory with automated gradient waveform design

Gradient pre-emphasis to counteract first-order concomitant fields on asymmetric MRI gradient systems

NonCartesian MR image reconstruction with integrated gradient nonlinearity correction

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