Simultaneous multi-slice T1 mapping using MOLLI with blipped CAIPIRINHA bSSFP

Bentatou, Zakarya; Troalen, Thomas; Bernard, Monique; Guye, Maxime; Pini, Lauriane; Bartoli, Axel; Jacquier, Alexis; Kober, Frank; Rapacchi, Stanislas

doi:10.1016/j.mri.2020.03.006

Cited by 10 publications

(23 citation statements)

References 39 publications

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“…The FLASH imaging has been used in this study due to its resilience against off‐resonance and susceptibility artifacts at higher field strength, although SSFP cine MRI has inherent advantages in terms of contrast‐to‐noise ratio and acquisition speed 49 . However, SMS acceleration rates with SSFP sequences are limited for wider coverage in cardiac MRI applications 18,19,59 and were not considered in this study. We also note that in a 7T cine imaging study with retrospective gating, it was noted that to maintain steady state, phase‐encode lines per segment were chosen as a multiple of the SMS/multiband factor 12 .…”

Section: Discussionmentioning

confidence: 99%

“…8 Multiple studies have explored the use of SMS imaging in CMR for faster coverage. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] In particular, SMS acceleration has been used for myocardial T 1 mapping, 13,18 for cine imaging, 16,21 and for perfusion imaging 11,14,15,17,22 using both Cartesian and non-Cartesian acquisitions at different acceleration rates. However, due to coil geometry limitations, SMS acceleration remains limited for CMR, especially in conjunction with in-plane parallel imaging, in which leakage artifacts and noise amplification are observed at high acceleration rates, 23 necessitating improvements in reconstruction.…”

Section: Introductionmentioning

confidence: 99%

“…Simultaneous multislice imaging is typically coupled with controlled aliasing, to further increase dissimilarities among the coil profiles across the slices and to reduce g‐factor noise amplification 8 . Multiple studies have explored the use of SMS imaging in CMR for faster coverage 9‐22 . In particular, SMS acceleration has been used for myocardial T 1 mapping, 13,18 for cine imaging, 16,21 and for perfusion imaging 11,14,15,17,22 using both Cartesian and non‐Cartesian acquisitions at different acceleration rates.…”

Section: Introductionmentioning

confidence: 99%

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Improved simultaneous multislice cardiac MRI using readout concatenated k‐space SPIRiT (ROCK‐SPIRiT)

Demirel

Weingärtner

Moeller

et al. 2021

Magnetic Resonance in Med

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To develop and evaluate a simultaneous multislice (SMS) reconstruction technique that provides noise reduction and leakage blocking for highly accelerated cardiac MRI. Methods: ReadOut Concatenated k-space SPIRiT (ROCK-SPIRiT) uses the concept of readout concatenation in image domain to represent SMS encoding, and performs coil self-consistency as in SPIRiT-type reconstruction in an extended k-space, while allowing regularization for further denoising. The proposed method is implemented with and without regularization, and validated on retrospectively SMS-accelerated cine imaging with threefold SMS and twofold in-plane acceleration. ROCK-SPIRiT is compared with two leakage-blocking SMS reconstruction methods: readout-SENSE-GRAPPA and split slice-GRAPPA. Further evaluation and comparisons are performed using prospectively SMS-accelerated cine imaging. Results: Results on retrospectively threefold SMS and twofold in-plane accelerated cine imaging show that ROCK-SPIRiT without regularization significantly improves on existing methods in terms of PSNR (readout-SENSE-GRAPPA:

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improved simultaneous multislice cardiac MRI using readout concatenated k‐space SPIRiT (ROCK‐SPIRiT)

Demirel

Weingärtner

Moeller

et al. 2021

Magnetic Resonance in Med

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“…Such methods generally require two unique RF pulses per shift in the slice direction. This study used blipped‐CAIPI, as did another recent study 27 however, our presented framework with the VERSE‐MB approach 17 is compatible with RF phase‐cycling because the gradient is not further optimized after applying the CAIPI modulation. This is because once

B_{1}^{control}

is set, the pulse duration becomes fixed; therefore, a CAIPI phase offset does not change RF energy per Parseval’s theorem.…”

Section: Discussionmentioning

confidence: 99%

“…Both design methods start with a SB constant gradient RF pulse waveform, and then compress this in time using VERSE for the SB case, and then further apply temporal modulation after VERSE for the MB case 17 . Amplitude‐only modulation was used to avoid known hardware issues with RF fidelity 26,27 . The TR‐optimal pulses were always compared against matched constant gradient pulse waveforms (ie, same starting pulse shape), which were also optimized to minimize the TR by adjusting their peak

B_{1}

amplitude accordingly.…”

Section: Methodsmentioning

confidence: 99%

Minimum TR radiofrequency‐pulse design for rapid gradient echo sequences

Seada

Price

Hajnal

et al. 2021

Magnetic Resonance in Med

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A framework to design radiofrequency (RF) pulses specifically to minimize the TR of gradient echo sequences is presented, subject to hardware and physiological constraints. Methods: Single-band and multiband (MB) RF pulses can be reduced in duration using variable-rate selective excitation (VERSE) VERSE for a range of flip angles; however, minimum-duration pulses do not guarantee minimum TR because these can lead to a high specific absorption rate (SAR). The optimal RF pulse is found by meeting spatial encoding, peripheral nerve stimulation (PNS) and SAR constraints. A TR reduction for a range of designs is achieved and an application of this in an MB cardiac balanced steady-state free-precession (bSSFP) experiment is presented. Gradient imperfections and their imaging effects are also considered. Results: Sequence TR with low-time bandwidth product (TBP) pulses, as used in bSSFP, was reduced up to 14%, and the TR when using high TBP pulses, as used in slab-selective imaging, was reduced by up to 72%. A breath-hold cardiac exam was reduced by 46% using both MB and the TR-optimal framework. The importance of RF-based correction of gradient imperfections is demonstrated. PNS was not a practical limitation. Conclusion: The TR-optimal framework designs RF pulses for a range of pulse parameters, specifically to minimize sequence TR. K E Y W O R D S cardiac, radiofrequency pulse design, rapid imaging, simultaneous multislice (SMS) 1 | INTRODUCTION Rapid gradient echo sequences, including spoiled gradient echo (SPGR) and steady-state free precession (SSFP) are used across MRI for a wide range of clinical and research applications. These sequences typically acquire one line of k-space per radiofrequency (RF) excitation; therefore, minimizing TR is key to fast image acquisition. This is particularly relevant for cine cardiac imaging 1-3 in which the TR determines the breath-hold duration. Furthermore, reducing TR for bSSFP also limits the impact of banding artifacts, which can become problematic for challenging B 0-shimming scenarios such as cardiac applications, especially at 3T and above. The minimum TR achievable is determined by multiple factors including the durations of image encoding gradients, peripheral nerve stimulation (PNS) predictions, 4 and specific absorption rate (SAR). The latter is particularly limiting for applications

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Myocardial First‐Pass Perfusion With Increased Anatomic Coverage at 3 T Using Autocalibrated Multiband Imaging

Zou

Yuan²,

Ding³

et al. 2022

Magnetic Resonance Imaging

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Background: Myocardial first-pass perfusion (FPP) imaging is a useful cardiac MRI method for the diagnosis of coronary artery disease. However, conventional 2D multislice FPP acquisitions usually have gaps between myocardium slices, which limits the overall assessment of myocardial ischemia. Purpose: To increase the anatomic coverage of myocardial FPP imaging at 3 T by implementing both autocalibrated multiband (MB) acquisition and k-t space acceleration with compress sensing (CS) reconstruction, without the need for additional reference scans. Study Type: Phantom and prospective human studies. Phantom/Subjects: A T1MES (T1 Mapping and ECV Standardization in cardiovascular magnetic resonance) phantom and 20 subjects (12 healthy subjects and 8 patients, 10 males, age 42 AE 16 years). Field Strength/Sequence: A 3 T/saturation recovery prepared gradient echo sequence with contrast administration. Assessment: Phantom experiments were performed to compare the performance of autocalibrated MB-FPP with k-t acceleration using slice-GRAPPA and CS reconstructions. In vivo experiments were performed to compare the performance of conventional FPP (2.5Â acceleration) with autocalibrated MB + CS-FPP (6Â acceleration). In phantom experiments, the error maps were calculated. In in vivo experiments, the contrast ratio (CR) and blurring were quantitatively measured, while image quality, perceived signal-to-noise ratio (SNR), and artifact level were qualitatively graded by three cardiologists on a 4-point scale. Statistical Tests: Wilcoxon signed-rank test, paired t-test. A P value <0.05 was considered statistically significant. Results: In phantom experiments, residual artifact was reduced using the MB + CS-FPP reconstruction method compared with using the MB + slice-GRAPPA reconstruction method. In in vivo experiments, the proposed autocalibrated MB + CS-FPP method demonstrated significantly higher CR (3.52 AE 0.78 vs 2.91 AE 0.81) and had significantly better perceived SNR (2.69 AE 0.29 vs 2.48 AE 0.31) compared to the conventional sequence. Compared with conventional FPP, MB + CS-FPP doubled the spatial coverage (MB + CS-FPP vs conventional FPP) without compromising the image quality (2.69 AE 0.26 vs 2.60 AE 0.30) or increasing the artifact level (2.60 AE 0.26 vs 2.52 AE 0.31). Conclusion: Autocalibrated MB + CS-FPP improved the myocardial coverage and achieved comparable image quality with the same spatial resolution and scan time as conventional FPP and is a promising technique for clinical myocardial perfusion imaging.

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Simultaneous multi-slice T1 mapping using MOLLI with blipped CAIPIRINHA bSSFP

Cited by 10 publications

References 39 publications

Improved simultaneous multislice cardiac MRI using readout concatenated k‐space SPIRiT (ROCK‐SPIRiT)

Improved simultaneous multislice cardiac MRI using readout concatenated k‐space SPIRiT (ROCK‐SPIRiT)

Minimum TR radiofrequency‐pulse design for rapid gradient echo sequences

Myocardial First‐Pass Perfusion With Increased Anatomic Coverage at 3 T Using Autocalibrated Multiband Imaging

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