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Bias‐reduced neural networks for parameter estimation in quantitative MRI Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-04 Andrew Mao, Sebastian Flassbeck, Jakob Assländer
PurposeTo develop neural network (NN)‐based quantitative MRI parameter estimators with minimal bias and a variance close to the Cramér–Rao bound.Theory and MethodsWe generalize the mean squared error loss to control the bias and variance of the NN's estimates, which involves averaging over multiple noise realizations of the same measurements during training. Bias and variance properties of the resulting
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Multiparametric exchange protons using Z‐spectrum analysis proton (ZAP) and CEST on phantoms and human abdomen Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-04 Vadim Malis, Mitsue Miyazaki
PurposeThis study aims to investigate a multiparametric exchange proton approach using CEST and Z‐spectrum analysis protons (ZAP) in human abdominal organs, focusing on tissue differentiation for a potential early biomarker of abnormality. Prior to human studies, CEST and ZAP effects were studied in phantoms containing exchange protons.MethodsPhantoms composed of iopamidol and iohexol solutions with
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Improved quantification in CEST‐MRI by joint spatial total generalized variation Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-04 Markus Huemer, Clemens Stilianu, Oliver Maier, Moritz Simon Fabian, Manuel Schmidt, Arnd Doerfler, Kristian Bredies, Moritz Zaiss, Rudolf Stollberger
PurposeIn this work, the use of joint Total Generalized Variation (TGV) regularization to improve Multipool‐Lorentzian fitting of chemical exchange saturation transfer (CEST) Spectra in terms of stability and parameter signal‐to‐noise ratio (SNR) was investigated.Theory and MethodsThe joint TGV term was integrated into the nonlinear parameter fitting problem. To increase convergence and weight the
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High‐resolution anatomical imaging of the fetal brain with a reduced field of view using outer volume suppression Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-04 MinJung Jang, Ajay Gupta, Arzu Kovanlikaya, Jessica E. Scholl, Zungho Zun
PurposeTo achieve high‐resolution fetal brain anatomical imaging without introducing image artifacts by reducing the FOV, and to demonstrate improved image quality compared to conventional full‐FOV fetal brain imaging.MethodsReduced FOV was achieved by applying outer volume suppression (OVS) pulses immediately prior to standard single‐shot fast spin echo (SSFSE) imaging. In the OVS preparation, a saturation
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Fast magnetization transfer saturation imaging of the brain using MP2RAGE T1 mapping Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-04 Christopher D. Rowley, Mark C. Nelson, Jennifer S. W. Campbell, Ilana R. Leppert, G. Bruce Pike, Christine L. Tardif
PurposeMagnetization transfer saturation (MTsat) mapping is commonly used to examine the macromolecular content of brain tissue. This study compared variable flip angle (VFA) T1 mapping against compressed‐sensing MP2RAGE (csMP2RAGE) T1 mapping for accelerating MTsat imaging.MethodsVFA, MP2RAGE, and csMP2RAGE were compared against inversion‐recovery T1 in an aqueous phantom at 3 T. The same 1‐mm VFA
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Velocity‐compensated intravoxel incoherent motion of the human calf muscle Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-01 Christoph M. Stuprich, Martin Loh, Johannes T. Nemerth, Armin M. Nagel, Michael Uder, Frederik B. Laun
PurposeTo determine whether intravoxel incoherent motion (IVIM) describes the blood perfusion in muscles better, assuming pseudo diffusion (Bihan Model 1) or ballistic motion (Bihan Model 2).MethodsIVIM parameters were measured in 18 healthy subjects with three different diffusion gradient time profiles (bipolar with two diffusion times and one with velocity compensation) and 17 b‐values (0–600 s/mm2)
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Accelerated motion correction with deep generative diffusion models Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-01 Brett Levac, Sidharth Kumar, Ajil Jalal, Jonathan I. Tamir
PurposeThe aim of this work is to develop a method to solve the ill‐posed inverse problem of accelerated image reconstruction while correcting forward model imperfections in the context of subject motion during MRI examinations.MethodsThe proposed solution uses a Bayesian framework based on deep generative diffusion models to jointly estimate a motion‐free image and rigid motion estimates from subsampled
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Distortionless, free‐breathing, and respiratory resolved 3D diffusion weighted imaging of the abdomen Magn. Reson. Med. (IF 3.3) Pub Date : 2024-05-01 Philip K. Lee, Xuetong Zhou, Nan Wang, Ali B. Syed, Ryan L. Brunsing, Shreyas S. Vasanawala, Brian A. Hargreaves
PurposeAbdominal imaging is frequently performed with breath holds or respiratory triggering to reduce the effects of respiratory motion. Diffusion weighted sequences provide a useful clinical contrast but have prolonged scan times due to low signal‐to‐noise ratio (SNR), and cannot be completed in a single breath hold. Echo‐planar imaging (EPI) is the most commonly used trajectory for diffusion weighted
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Erratum to: Velocity‐selective arterial spin labeling perfusion MRI: A review of the state of the art and recommendations for clinical implementation (Magn Reson Med. 2022; 88:1528–1547) Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-25 Qin Qin, David C. Alsop, Divya S. Bolar, Luis Hernandez‐Garcia, James Meakin, Dapeng Liu, Krishna S. Nayak, Sophie Schmid, Matthias J. P. van Osch, Eric C. Wong, Joseph G. Woods, Greg Zaharchuk, Moss Y. Zhao, Zungho Zun, Jia Guo
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Sodium Triple Quantum MR Signal Extraction Using a Single‐Pulse Sequence with Single Quantum Time Efficiency Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Simon Reichert, Victor Schepkin, Dennis Kleimaier, Frank G. Zöllner, Lothar R. Schad
PurposeSodium triple quantum (TQ) signal has been shown to be a valuable biomarker for cell viability. Despite its clinical potential, application of Sodium TQ signal is hindered by complex pulse sequences with long scan times. This study proposes a method to approximate the TQ signal using a single excitation pulse without phase cycling.MethodsThe proposed method is based on a single excitation pulse
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An inflated adiabatic T1ρ by T1 relaxation in biological tissues Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Yuxi Pang
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B1 inhomogeneity corrected CEST MRI based on direct saturation removed omega plot model at 5T Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Qiting Wu, Pengcheng Gong, Shengping Liu, Ye Li, Dong Liang, Hairong Zheng, Yin Wu
PurposeCEST can image macromolecules/compounds via detecting chemical exchange between labile protons and bulk water. B1 field inhomogeneity impairs CEST quantification. Conventional B1 inhomogeneity correction methods depend on interpolation algorithms, B1 choices, acquisition number or calibration curves, making reliable correction challenging. This study proposed a novel B1 inhomogeneity correction
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Practical utilization of nonlinear spatial encoding: Fast field mapping and FRONSAC‐wave Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Horace Z. Zhang, R. Todd Constable, Gigi Galiana
PurposeTo study the additional value of FRONSAC encoding in 2D and 3D wave sequences, implementing a simple strategy to trajectory mapping for FRONSAC encoding gradients.Theory and MethodsThe nonlinear gradient trajectory for each voxel was estimated by exploiting the sparsity of the point spread function in the frequency domain. Simulations and in‐vivo experiments were used to analyze the performance
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Accelerated free‐breathing liver fat and R2* quantification using multi‐echo stack‐of‐radial MRI with motion‐resolved multidimensional regularized reconstruction: Initial retrospective evaluation Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Xiaodong Zhong, Marcel D. Nickel, Stephan A. R. Kannengiesser, Brian M. Dale, Fei Han, Chang Gao, Shu‐Fu Shih, Qing Dai, Omar Curiel, Tsu‐Chin Tsao, Holden H. Wu, Vibhas Deshpande
PurposeTo improve image quality, mitigate quantification biases and variations for free‐breathing liver proton density fat fraction (PDFF) and quantification accelerated by radial k‐space undersampling.MethodsA free‐breathing multi‐echo stack‐of‐radial MRI method was developed with compressed sensing with multidimensional regularization. It was validated in motion phantoms with reference acquisitions
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Performance of receive head arrays versus ultimate intrinsic SNR at 7 T and 10.5 T Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Bei Zhang, Jerahmie Radder, Ilias Giannakopoulos, Andrea Grant, Russell Lagore, Matt Waks, Nader Tavaf, Pierre‐Francois Van de Moortele, Gregor Adriany, Alireza Sadeghi‐Tarakameh, Yigitcan Eryaman, Riccardo Lattanzi, Kamil Uğurbil
PurposeWe examined magnetic field dependent SNR gains and ability to capture them with multichannel receive arrays for human head imaging in going from 7 T, the most commonly used ultrahigh magnetic field (UHF) platform at the present, to 10.5 T, which represents the emerging new frontier of >10 T in UHFs.MethodsElectromagnetic (EM) models of 31‐channel and 63‐channel multichannel arrays built for
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In vivo diffusion MRI of the human heart using a 300 mT/m gradient system Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Maryam Afzali, Lars Mueller, Sam Coveney, Fabrizio Fasano, Christopher John Evans, Maria Engel, Filip Szczepankiewicz, Irvin Teh, Erica Dall'Armellina, Derek K. Jones, Jürgen E. Schneider
PurposeThis work reports for the first time on the implementation and application of cardiac diffusion‐weighted MRI on a Connectom MR scanner with a maximum gradient strength of 300 mT/m. It evaluates the benefits of the increased gradient performance for the investigation of the myocardial microstructure.MethodsCardiac diffusion‐weighted imaging (DWI) experiments were performed on 10 healthy volunteers
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Retrospective correction of second‐order concomitant fields in 3D axial stack‐of‐spirals imaging on a high‐performance gradient system Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Afis Ajala, Nastaren Abad, Thomas K. F. Foo, Seung‐Kyun Lee
PurposeMRI using 3D stack‐of‐spirals (SoS) readout on a high‐performance gradient system is subject to strong second‐order, spatially varying concomitant fields, which can lead to signal dropout and blurring artifacts that become more significant at locations farther from the gradient isocenter. A method for compensating for second‐order concomitant fields in 3D axial SoS image reconstruction is described
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Effects of prospective motion correction on perivascular spaces at 7T MRI evaluated using motion artifact simulation Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Bingbing Zhao, Yichen Zhou, Xiaopeng Zong
PurposeThe effectiveness of prospective motion correction (PMC) is often evaluated by comparing artifacts in images acquired with and without PMC (NoPMC). However, such an approach is not applicable in clinical setting due to unavailability of NoPMC images. We aim to develop a simulation approach for demonstrating the ability of fat‐navigator‐based PMC in improving perivascular space (PVS) visibility
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Real‐time imaging of decompression gas bubble growth in the spinal cord of live rats Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Roman Alvarado, Ulrich M. Scheven, Jens‐Christian Meiners
PurposeTo observe the growth and resolution of decompression gas bubbles in the spinal cord of live rats in real time using MRI.MethodsWe constructed an MRI‐compatible pressure chamber system to visualize gas bubble dynamics in deep tissues in real time. The system pressurizes and depressurizes rodents inside an MRI scanner and monitors their respiratory rate, heart rate, and body temperature while
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Imaging of adeno‐associated viral capsids for purposes of gene editing using CEST NMR/MRI Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Bonnie Lam, Mark Velasquez, Tomoko Ogiyama, Kevin Godines, Fan‐Yun Szu, A. J. Velasquez‐Mao, Wissam AlGhuraibawi, Jingshen Wang, Phillip B. Messersmith, Moriel H. Vandsburger
PurposeGene therapy using adeno‐associated virus (AAV) vector‐mediated gene delivery has undergone substantial growth in recent years with promising results in both preclinical and clinical studies, as well as emerging regulatory approval. However, the inability to quantify the efficacy of gene therapy from cellular delivery of gene‐editing technology to specific functional outcomes is an obstacle
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Fully automated planning for anatomical fetal brain MRI on 0.55T Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Sara Neves Silva, Sarah McElroy, Jordina Aviles Verdera, Kathleen Colford, Kamilah St Clair, Raphael Tomi‐Tricot, Alena Uus, Valéry Ozenne, Megan Hall, Lisa Story, Kuberan Pushparajah, Mary A. Rutherford, Joseph V. Hajnal, Jana Hutter
PurposeWidening the availability of fetal MRI with fully automatic real‐time planning of radiological brain planes on 0.55T MRI.MethodsDeep learning‐based detection of key brain landmarks on a whole‐uterus echo planar imaging scan enables the subsequent fully automatic planning of the radiological single‐shot Turbo Spin Echo acquisitions. The landmark detection pipeline was trained on over 120 datasets
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Simultaneous multi‐transient linear‐combination modeling of MRS data improves uncertainty estimation Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-23 Helge Jörn Zöllner, Christopher Davies‐Jenkins, Dunja Simicic, Assaf Tal, Jeremias Sulam, Georg Oeltzschner
PurposeThe interest in applying and modeling dynamic MRS has recently grown. Two‐dimensional modeling yields advantages for the precision of metabolite estimation in interrelated MRS data. However, it is unknown whether including all transients simultaneously in a 2D model without averaging (presuming a stable signal) performs similarly to one‐dimensional (1D) modeling of the averaged spectrum. Therefore
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Effect of MR head coil geometry on deep‐learning‐based MR image reconstruction Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-22 Natalia Dubljevic, Stephen Moore, Michel Louis Lauzon, Roberto Souza, Richard Frayne
PurposeTo investigate whether parallel imaging‐imposed geometric coil constraints can be relaxed when using a deep learning (DL)‐based image reconstruction method as opposed to a traditional non‐DL method.Theory and MethodsTraditional and DL‐based MR image reconstruction approaches operate in fundamentally different ways: Traditional methods solve a system of equations derived from the image data whereas
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SPINNED: Simulation‐based physics‐informed neural network for deconvolution of dynamic susceptibility contrast MRI perfusion data Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Muhammad Asaduddin, Eung Yeop Kim, Sung‐Hong Park
PurposeTo propose the simulation‐based physics‐informed neural network for deconvolution of dynamic susceptibility contrast (DSC) MRI (SPINNED) as an alternative for more robust and accurate deconvolution compared to existing methods.MethodsThe SPINNED method was developed by generating synthetic tissue residue functions and arterial input functions through mathematical simulations and by using them
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Highly‐accelerated CEST MRI using frequency‐offset‐dependent k‐space sampling and deep‐learning reconstruction Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Chuyu Liu, Zhongsen Li, Zhensen Chen, Benqi Zhao, Zhuozhao Zheng, Xiaolei Song
PurposeTo develop a highly accelerated CEST Z‐spectral acquisition method using a specifically‐designed k‐space sampling pattern and corresponding deep‐learning‐based reconstruction.MethodsFor k‐space down‐sampling, a customized pattern was proposed for CEST, with the randomized probability following a frequency‐offset‐dependent (FOD) function in the direction of saturation offset. For reconstruction
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Minimizing electric fields and increasing peripheral nerve stimulation thresholds using a body gradient array coil Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Reza Babaloo, Ergin Atalar
PurposeTo demonstrate the performance of gradient array coils in minimizing switched‐gradient‐induced electric fields (E‐fields) and improving peripheral nerve stimulation (PNS) thresholds while generating gradient fields with adjustable linearity across customizable regions of linearity (ROLs).MethodsA body gradient array coil is used to reduce the induced E‐fields on the surface of a body model by
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Robust multishot diffusion‐weighted imaging of the abdomen with region‐based shot rejection Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Philip K. Lee, Xuetong Zhou, Brian A. Hargreaves
PurposeDiffusion‐weighted (DW) imaging provides a useful clinical contrast, but is susceptible to motion‐induced dephasing caused by the application of strong diffusion gradients. Phase navigators are commonly used to resolve shot‐to‐shot motion‐induced phase in multishot reconstructions, but poor phase estimates result in signal dropout and Apparent Diffusion Coefficient (ADC) overestimation. These
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In vivo T2 measurements of the fetal brain using single‐shot fast spin echo sequences Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Suryava Bhattacharya, Anthony N. Price, Alena Uus, Helena S. Sousa, Massimo Marenzana, Kathleen Colford, Peter Murkin, Maggie Lee, Lucilio Cordero‐Grande, Rui Pedro A. G. Teixeira, Shaihan J. Malik, Maria Deprez
PurposeWe propose a quantitative framework for motion‐corrected T2 fetal brain measurements in vivo and validate the single‐shot fast spin echo (SS‐FSE) sequence to perform these measurements.MethodsStacks of two‐dimensional SS‐FSE slices are acquired with different echo times (TE) and motion‐corrected with slice‐to‐volume reconstruction (SVR). The quantitative T2 maps are obtained by a fit to a dictionary
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Spatiotemporal encoding MRI in a portable low‐field system Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Yueqi Qiu, Ke Dai, Sijie Zhong, Suen Chen, Changyue Wang, Hao Chen, Lucio Frydman, Zhiyong Zhang
PurposeDemonstrate the potential of spatiotemporal encoding (SPEN) MRI to deliver largely undistorted 2D, 3D, and diffusion weighted images on a 110 mT portable system.MethodsSPEN's quadratic phase modulation was used to subsample the low‐bandwidth dimension of echo planar acquisitions, delivering alias‐free images with an enhanced immunity to image distortions in a laboratory‐built, low‐field, portable
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Knowledge‐driven deep learning for fast MR imaging: Undersampled MR image reconstruction from supervised to un‐supervised learning Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-16 Shanshan Wang, Ruoyou Wu, Sen Jia, Alou Diakite, Cheng Li, Qiegen Liu, Hairong Zheng, Leslie Ying
Deep learning (DL) has emerged as a leading approach in accelerating MRI. It employs deep neural networks to extract knowledge from available datasets and then applies the trained networks to reconstruct accurate images from limited measurements. Unlike natural image restoration problems, MRI involves physics‐based imaging processes, unique data properties, and diverse imaging tasks. This domain knowledge
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Recommendations for quantitative cerebral perfusion MRI using multi-timepoint arterial spin labeling: Acquisition, quantification, and clinical applications Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-09 Joseph G. Woods, Eric Achten, Iris Asllani, Divya S. Bolar, Weiying Dai, John A. Detre, Audrey P. Fan, María A. Fernández-Seara, Xavier Golay, Matthias Günther, Jia Guo, Luis Hernandez-Garcia, Mai-Lan Ho, Meher R. Juttukonda, Hanzhang Lu, Bradley J. MacIntosh, Ananth J. Madhuranthakam, Henk-Jan Mutsaerts, Thomas W. Okell, Laura M. Parkes, Nandor Pinter, Joana Pinto, Qin Qin, Marion Smits, Yuriko Suzuki
Accurate assessment of cerebral perfusion is vital for understanding the hemodynamic processes involved in various neurological disorders and guiding clinical decision-making. This guidelines article provides a comprehensive overview of quantitative perfusion imaging of the brain using multi-timepoint arterial spin labeling (ASL), along with recommendations for its acquisition and quantification. A
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CMRsim–A python package for cardiovascular MR simulations incorporating complex motion and flow Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-05
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Simultaneous brain and neck time‐of‐flight MRA using spiral multiband with localized quadratic encoding Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-05 Xi Peng, Dinghui Wang, Daniel Borup, Guruprasad Krishnamoorthy, James G. Pipe
PurposeTo develop a method that achieves simultaneous brain and neck time‐of‐flight (ToF) magnetic resonance angiography (MRA) within feasible scan timeframes.MethodsLocalized quadratic (LQ) encoding is efficient for both signal‐to‐noise ratio (SNR) and in‐flow enhancement. We proposed a spiral multiband LQ method to enable simultaneous intracranial and carotid ToF‐MRA within a single scan. To address
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Deep learning‐based rapid image reconstruction and motion correction for high‐resolution cartesian first‐pass myocardial perfusion imaging at 3T Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-05 Junyu Wang, Michael Salerno
PurposeTo develop and evaluate a deep learning (DL) ‐based rapid image reconstruction and motion correction technique for high‐resolution Cartesian first‐pass myocardial perfusion imaging at 3T with whole‐heart coverage for both single‐slice (SS) and simultaneous multi‐slice (SMS) acquisitions.Methods3D physics‐driven unrolled network architectures were utilized for the reconstruction of high‐resolution
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MR signature matching (MRSIGMA) implementation for true real‐time free‐breathing volumetric imaging with sub‐200 ms latency on an MR‐Linac Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-05 Saad Siddiq, Victor Murray, Neelam Tyagi, Pim Borman, Chengcheng Gui, Christopher Crane, Can Wu, Ricardo Otazo
PurposeDevelop a true real‐time implementation of MR signature matching (MRSIGMA) for free‐breathing 3D MRI with sub‐200 ms latency on the Elekta Unity 1.5T MR‐Linac.MethodsMRSIGMA was implemented on an external computer with a network connection to the MR‐Linac. Stack‐of‐stars with partial kz sampling was used to accelerate data acquisition and ReconSocket was employed for simultaneous data transmission
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Phase distribution graphs for fast, differentiable, and spatially encoded Bloch simulations of arbitrary MRI sequences Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-05 Jonathan Endres, Simon Weinmüller, Hoai Nam Dang, Moritz Zaiss
PurposeAn analytical approach to Bloch simulations for MRI sequences is introduced that enables time efficient calculations of signals free of Monte‐Carlo noise, while providing full flexibility and differentiability in RF flip angles, RF phases, magnetic field gradients and time, as well as insights into image formation.Theory and MethodsWe present an implementation of the extended phase graph (EPG)
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The “hidden noise” problem in MR image reconstruction Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-05 Jiayang Wang, Di An, Justin P. Haldar
PurposeThe performance of modern image reconstruction methods is commonly judged using quantitative error metrics like root mean squared‐error and the structural similarity index, which are calculated by comparing reconstructed images against fully sampled reference data. In practice, the reference data will contain noise and is not a true gold standard. In this work, we demonstrate that the “hidden
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Genetic control of MRI contrast using the manganese transporter Zip14 Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-04 Harikrishna Rallapalli, Eleanor C. McCall, Alan P. Koretsky
PurposeGene‐expression reporter systems, such as green fluorescent protein, have been instrumental to understanding biological processes in living organisms at organ system, tissue, cell, and molecular scales. More than 30 years of work on developing MRI‐visible gene‐expression reporter systems has resulted in a variety of clever application‐specific methods. However, these techniques have not yet
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Anisotropy of T2 and T1ρ relaxation time in articular cartilage at 3 T Magn. Reson. Med. (IF 3.3) Pub Date : 2024-04-01 Ville Kantola, Jouni Karjalainen, Tomi Jaakola, Henri P. P. Leskinen, Mikko J. Nissi, Victor Casula, Miika T. Nieminen
PurposeThe anisotropy of R2 and R1ρ relaxation rates in articular cartilage contains information about the collagenous structure of the tissue. Here we determine and study the anisotropic and isotropic components of T2 and T1ρ relaxation parameters in articular cartilage with a clinical 3T MRI device. Furthermore, a visual representation of the topographical variation in anisotropy is given via anisotropy
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Compartmental anisotropy of filtered exchange imaging (FEXI) in human white matter: What is happening in FEXI? Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Hyeong‐Geol Shin, Xu Li, Hye‐Young Heo, Linda Knutsson, Filip Szczepankiewicz, Markus Nilsson, Peter C. M. van Zijl
PurposeTo investigate the effects of compartmental anisotropy on filtered exchange imaging (FEXI) in white matter (WM).Theory and MethodsFEXI signals were measured using multiple combinations of diffusion filter and detection directions in five healthy volunteers. Additional filters, including a trace‐weighted diffusion filter with trapezoidal gradients, a spherical b‐tensor encoded diffusion filter
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Repeatability of Open‐MOLLI: An open‐source inversion recovery myocardial T1 mapping sequence for fast prototyping Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Andreia S. Gaspar, Nuno A. Silva, António M. Ferreira, Rita G. Nunes
PurposeTo develop an open‐source prototype of myocardial T1 mapping (Open‐MOLLI) to improve accessibility to cardiac T1 mapping and evaluate its repeatability. With Open‐MOLLI, we aim to enable faster implementation and testing of sequence modifications and to facilitate inter‐scanner and cross‐vendor reproducibility studies.MethodsOpen‐MOLLI is an inversion‐recovery sequence using a balanced SSFP
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A vendor‐neutral EPI sequence for hyperpolarized 13C MRI Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Tyler Blazey, Ashley Shaw, Cornelius von Morze
PurposeTo develop a flexible, vendor‐neutral EPI sequence for hyperpolarized 13C metabolic imaging.MethodsAn open‐source EPI sequence consisting of a metabolite‐specific spectral‐spatial RF excitation pulse and a customizable EPI readout was created using the Pulseq framework. To explore the flexibility of our sequence, we tested several versions of the sequence including a symmetric 3D readout with
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Direct angiographic comparison of different velocity‐selective saturation, inversion, and DANTE labeling modules on cerebral arteries Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Dapeng Liu, Dan Zhu, Qin Qin
PurposeThis study evaluated the velocity‐selective (VS) MRA with different VS labeling modules, including double refocused hyperbolic tangent, eight‐segment B1‐insensitive rotation, delay alternating with nutation for tailored excitation, Fourier transform–based VS saturation, and Fourier transform–based inversion.MethodsThese five VS labeling modules were evaluated first through Bloch simulations
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MR elastography–based slip interface imaging (SII) for functional assessment of myofascial interfaces: A feasibility study Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Emi Hojo, Yi Sui, Xiang Shan, Keni Zheng, Phillip Rossman, Armando Manduca, Garret M. Powell, Kai‐Nan An, Kristin D. Zhao, Brent A. Bauer, Richard L. Ehman, Ziying Yin
PurposeAbnormal adherence at functional myofascial interfaces is hypothesized as an important phenomenon in myofascial pain syndrome. This study aimed to investigate the feasibility of MR elastography (MRE)–based slip interface imaging (SII) to visualize and assess myofascial mobility in healthy volunteers.MethodsSII was used to assess local shear strain at functional myofascial interfaces in the flexor
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Vessel‐specific quantification of cerebral venous oxygenation with velocity‐encoding preparation and rapid acquisition Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Zixuan Lin, Dengrong Jiang, Yiwen Hong, Yi Zhang, Yi‐Cheng Hsu, Hanzhang Lu, Dan Wu
PurposeNon‐invasive measurement of cerebral venous oxygenation (Yv) is of critical importance in brain diseases. The present work proposed a fast method to quantify regional Yv map for both large and small veins.MethodsA new sequence was developed, referred to as TRU‐VERA (T2 relaxation under velocity encoding and rapid acquisition, which isolates blood spins from static tissue with velocity‐encoding
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3D balanced SSFP UTE MRI for multiple contrasts whole brain imaging Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-25 Xin Shen, Eduardo Caverzasi, Yang Yang, Xiaoxi Liu, Ari Green, Roland G. Henry, Uzay Emir, Peder E. Z. Larson
PurposeThis study aimed to develop a new high‐resolution MRI sequence for the imaging of the ultra‐short transverse relaxation time (uT2) components in the brain, while simultaneously providing proton density (PD) contrast for reference and quantification.TheoryThe sequence combines low flip angle balanced SSFP (bSSFP) and UTE techniques, together with a 3D dual‐echo rosette k‐space trajectory for
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Signatures of microstructure in gradient‐echo and spin‐echo signals Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-23 Pippa Storey, Dmitry S. Novikov
PurposeTo determine whether the spatial scale and magnetic susceptibility of microstructure can be evaluated robustly from the decay of gradient‐echo and spin‐echo signals.Theory and MethodsGradient‐echo and spin‐echo images were acquired from suspensions of spherical polystyrene microbeads of 10, 20, and 40 μm nominal diameter. The sizes of the beads and their magnetic susceptibility relative to the
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Increasing the scan‐efficiency of pulmonary imaging at 0.55 T using iterative concomitant field and motion‐corrected reconstruction Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-19 Ahsan Javed, Rajiv Ramasawmy, Valéry Ozenne, Pan Su, Kelvin Chow, Adrienne Campbell‐Washburn
PurposeTo develop an iterative concomitant field and motion corrected (iCoMoCo) reconstruction for isotropic high‐resolution UTE pulmonary imaging at 0.55 T.MethodsA free‐breathing golden‐angle stack‐of‐spirals UTE sequence was used to acquire data for 8 min with prototype and commercial 0.55 T MRI scanners. The data was binned into 12 respiratory phases based on superior–inferior navigator readouts
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Reproducibility of arterial spin labeling cerebral blood flow image processing: A report of the ISMRM open science initiative for perfusion imaging (OSIPI)_and the ASL MRI challenge Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-19 Andre M. Paschoal, Joseph G. Woods, Joana Pinto, Esther E. Bron, Jan Petr, Flora A. Kennedy McConnell, Laura Bell, Maria‐Eleni Dounavi, Cassandra Gould van Praag, Henk J. M. M. Mutsaerts, Aaron Oliver Taylor, Moss Y. Zhao, Irène Brumer, Wei Siang Marcus Chan, Jack Toner, Jian Hu, Logan X. Zhang, Catarina Domingos, Sara P. Monteiro, Patrícia Figueiredo, Alexander G. J. Harms, Beatriz E. Padrela, Channelle
PurposeArterial spin labeling (ASL) is a widely used contrast‐free MRI method for assessing cerebral blood flow (CBF). Despite the generally adopted ASL acquisition guidelines, there is still wide variability in ASL analysis. We explored this variability through the ISMRM‐OSIPI ASL‐MRI Challenge, aiming to establish best practices for more reproducible ASL analysis.MethodsEight teams analyzed the challenge
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Pre‐excitation gradients for eddy current nulled convex optimized diffusion encoding (Pre‐ENCODE) Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-19 Matthew J. Middione, Michael Loecher, Xiaozhi Cao, Kawin Setsompop, Daniel B. Ennis
PurposeTo evaluate the use of pre‐excitation gradients for eddy current–nulled convex optimized diffusion encoding (Pre‐ENCODE) to mitigate eddy current–induced image distortions in diffusion‐weighted MRI (DWI).MethodsDWI sequences using monopolar (MONO), ENCODE, and Pre‐ENCODE were evaluated in terms of the minimum achievable echo time (TE) and eddy current‐induced image distortions using simulations
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Technical advances in motion‐robust MR thermometry Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-19 Kisoo Kim, Kazim Narsinh, Eugene Ozhinsky
Proton resonance frequency shift (PRFS) MR thermometry is the most common method used in clinical thermal treatments because of its fast acquisition and high sensitivity to temperature. However, motion is the biggest obstacle in PRFS MR thermometry for monitoring thermal treatment in moving organs. This challenge arises because of the introduction of phase errors into the PRFS calculation through multiple
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Integrating data distribution prior via Langevin dynamics for end‐to‐end MR reconstruction Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-12 Jing Cheng, Zhuo‐Xu Cui, Qingyong Zhu, Haifeng Wang, Yanjie Zhu, Dong Liang
PurposeTo develop a novel deep learning‐based method inheriting the advantages of data distribution prior and end‐to‐end training for accelerating MRI.MethodsLangevin dynamics is used to formulate image reconstruction with data distribution before facilitate image reconstruction. The data distribution prior is learned implicitly through the end‐to‐end adversarial training to mitigate the hyper‐parameter
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Intra‐scan RF power amplifier drift correction Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-12 Ali Aghaeifar, Dario Bosch, Rahel Heule, Sydney Williams, Philipp Ehses, Franck Mauconduit, Klaus Scheffler
PurposeThe drift in radiofrequency (RF) power amplifiers (RFPAs) is assessed and several contributing factors are investigated. Two approaches for prospective correction of drift are proposed and their effectiveness is evaluated.MethodsRFPA drift assessment encompasses both intra‐pulse and inter‐pulse drift analyses. Scan protocols with varying flip angle (FA), RF length, and pulse repetition time
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A 3D dual‐echo spiral sequence for simultaneous dynamic susceptibility contrast and dynamic contrast‐enhanced MRI with single bolus injection Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-12 Zhiqiang Li, Dinghui Wang, Melvyn B. Ooi, Poonam Choudhary, Sudarshan Ragunathan, John P. Karis, James G. Pipe, C. Chad Quarles, Ashley M. Stokes
PurposePerfusion MRI reveals important tumor physiological and pathophysiologic information, making it a critical component in managing brain tumor patients. This study aimed to develop a dual‐echo 3D spiral technique with a single‐bolus scheme to simultaneously acquire both dynamic susceptibility contrast (DSC) and dynamic contrast‐enhanced (DCE) data and overcome the limitations of current EPI‐based
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Reduced cross‐scanner variability using vendor‐agnostic sequences for single‐shell diffusion MRI Magn. Reson. Med. (IF 3.3) Pub Date : 2024-03-12 Qiang Liu, Lipeng Ning, Imam Ahmed Shaik, Congyu Liao, Borjan Gagoski, Berkin Bilgic, William Grissom, Jon‐Fredrik Nielsen, Maxim Zaitsev, Yogesh Rathi
PurposeTo reduce the inter‐scanner variability of diffusion MRI (dMRI) measures between scanners from different vendors by developing a vendor‐neutral dMRI pulse sequence using the open‐source vendor‐agnostic Pulseq platform.MethodsWe implemented a standard EPI based dMRI sequence in Pulseq. We tested it on two clinical scanners from different vendors (Siemens Prisma and GE Premier), systematically