Improved radial GRAPPA calibration for real‐time free‐breathing cardiac imaging

Seiberlich, Nicole; Ehses, Philipp; Duerk, Jeffrey L.; Gilkeson, Robert C.; Griswold, Mark A.

doi:10.1002/mrm.22618

Cited by 97 publications

(155 citation statements)

References 31 publications

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“…It is therefore advisable to search for complementary information in the data acquired immediately before or after the actual frame. For these reasons radial "through-time" GRAPPA [15] was recently extended to use self-calibration, but found to result in an insufficient number of GRAPPA kernels for restoring adequate image quality, so that respective cardiac applications lead to partial blurring of systolic frames [16].…”

Section: Nonlinear Inverse Reconstructionmentioning

confidence: 99%

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

Frahm¹,

Schätz²,

Untenberger³

et al. 2014

TOMIJ

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Abstract:Purpose: To evaluate the temporal accuracy of a self-consistent nonlinear inverse reconstruction method (NLINV) for real-time MRI using highly undersampled radial gradient-echo sequences and to present an open source framework for the motion assessment of real-time MRI methods.Methods: Serial image reconstructions by NLINV combine a joint estimation of individual frames and corresponding coil sensitivities with temporal regularization to a preceding frame. The temporal fidelity of the method was determined with a phantom consisting of water-filled tubes rotating at defined angular velocity. The conditions tested correspond to realtime cardiac MRI using SSFP contrast at 1.5 T (40 ms resolution) and T1 contrast at 3.0 T (33 ms and 18 ms resolution). In addition, the performance of a post-processing temporal median filter was evaluated.Results: NLINV reconstructions without temporal filtering yield accurate estimations as long as the speed of a small moving object corresponds to a spatial displacement during the acquisition of a single frame which is smaller than the object itself. Faster movements may lead to geometric distortions. For small objects moving at high velocity, a median filter may severely compromise the spatiotemporal accuracy.Conclusion: NLINV reconstructions offer excellent temporal fidelity as long as the image acquisition time is short enough to adequately sample ("freeze") the object movement. Temporal filtering should be applied with caution. The motion framework emerges as a valuable tool for the evaluation of real-time MRI methods.

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Section: Nonlinear Inverse Reconstructionmentioning

confidence: 99%

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

Frahm¹,

Schätz²,

Untenberger³

et al. 2014

TOMIJ

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“…Susceptibility artifacts: the benefit from parallel acceleration techniques (GRAPPA, SENSE), selective RF pulse (zonal oblique multi-slice EPI (ZOOM-EPI)), or RF multi-band technology It is well-known that parallel imaging techniques (generalized autocalibrating partially parallel acquisition (GRAPPA), array spatial sensitivity encoding technique (ASSET), sensitivity encoding (SENSE)) [37][38][39][40][41][42][43][44][45][46] allow substantial reduction of echo time (TE) and related susceptibility artifacts (see Fig. 3) leading to a subsequent improvement of image quality close to air-tissue interfaces.…”

Section: Diffusion Imagingmentioning

confidence: 99%

State-of-the-art MRI techniques in neuroradiology: principles, pitfalls, and clinical applications

et al. 2015

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This article reviews the most relevant state-of-the-art magnetic resonance (MR) techniques, which are clinically available to investigate brain diseases. MR acquisition techniques addressed include notably diffusion imaging (diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DKI)) as well as perfusion imaging (dynamic susceptibility contrast (DSC), arterial spin labeling (ASL), and dynamic contrast enhanced (DCE)). The underlying models used to process these images are described, as well as the theoretic underpinnings of quantitative diffusion and perfusion MR imaging-based methods. The technical requirements and how they may help to understand, classify, or follow-up neurological pathologies are briefly summarized. Techniques, principles, advantages but also intrinsic limitations, typical artifacts, and alternative solutions developed to overcome them are discussed. In this article, we also review routinely available three-dimensional (3D) techniques in neuro MRI, including state-of-the-art and emerging angiography sequences, and briefly introduce more recently proposed 3D quantitative neuro-anatomy sequences, and new technology, such as multi-slice and multi-transmit imaging.

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“…Recently, the combination of radial acquisition with parallel imaging has been presented as a promising alternative. 30 To calculate the GRAPPA kernels, a prescan is performed, consisting of several fully sampled images at several points in time. Then, kernels can be determined for each spatial point.…”

Section: Discussionmentioning

confidence: 99%

Free Breathing Real-Time Cardiac Cine Imaging With Improved Spatial Resolution at 3 T

Schwab¹,

Schwarz²,

Dietrich³

et al. 2013

Investigative Radiology

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Objectives: The aim of this study was to evaluate free-breathing single-shot real-time cine imaging for functional cardiac imaging at 3 T with increased spatial resolution. Special emphasis of this study was placed on the influence of parallel imaging techniques. Materials and Methods: Gradient echo phantom images were acquired with GRAPPA and modified SENSE reconstruction using both integrated and separate reference scans as well as TGRAPPA and TSENSE. In vivo measurements were performed for GRAPPA reconstruction with an integrated and a separate reference scan, as well as TGRAPPA using balanced steady-state free precession protocols. Three clinical protocols, rtLRInt (T res = 51.3 milliseconds; voxel, 2.5 Â 5.0 Â 10 mm 3 ), rtMRSep (T res = 48.8 milliseconds; voxel, 1.9 Â 3.1 Â 10 mm 3 ), and rtHRSep (T res = 48.3 milliseconds; voxel, 1.6 Â 2.6 Â 10 mm 3 ), were investigated on 20 volunteers using GRAPPA reconstruction with internal as well as separate reference scans. End-diastolic volume, end-systolic volume, ejection fraction, peak ejection rate, peak filling rate, and myocardial mass were evaluated for the left ventricle and compared with an electrocardiogram-triggered segmented readout cine protocol used as standard of reference. All studies were performed at 3 T. Results: Phantom and in vivo data demonstrate that the combination of GRAPPA reconstruction with a separate reference scan provides an optimal compromise of image quality as well as spatial and temporal resolution. Functional values (P values) for the standard of reference, rtLRInt, rtMRSep, and rtHRSep end-diastolic volume were 141 T 24 mL, 138 T 21 mL, 138 T 19 mL, and 128 T 33 mL, respectively (P = 0.7, 0.7, 0.4); end-systolic volume, 55 T 15 mL, 61 T 14 mL, 58 T 12 mL, and 55 T 20 mL, respectively (P = 0.23, 0.43, 0.62); ejection fraction, 61% T 5%, 57% T 5%, 58% T 4%, and 56% T 8%, respectively (P = 0.01, 0.11, 0.06); peak ejection rate, 481 T 73 mL/s, 425 T 62 mL/s, 434 T 67 mL/s, and 381 T 86 mL/s, respectively (P = 0.03, 0.04, 0.01); peak filling rate, 555 T 80 mL/s, 480 T 70 mL/s, 500 T 70 mL/s, and 438 T 108 mL/s, respectively (P = 0.007, 0.05, 0.004); and myocardial mass, 137 T 26 g, 141 T 25 g, 141 T 23 g, and 130 T 31 g, respectively (P = 0.62, 0.54, 0.99). Conclusions: Using a separate reference scan and high acceleration factors up to R = 6, single-shot real-time cardiac imaging offers adequate temporal and spatial resolution for accurate assessment of global left ventricular function in free breathing with short examination times.

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Improved radial GRAPPA calibration for real‐time free‐breathing cardiac imaging

Cited by 97 publications

References 31 publications

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

State-of-the-art MRI techniques in neuroradiology: principles, pitfalls, and clinical applications

Free Breathing Real-Time Cardiac Cine Imaging With Improved Spatial Resolution at 3 T

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