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Calibration‐free whole‐brain CEST imaging at 7T with parallel transmit pulse design for saturation homogeneity utilizing universal pulses (PUSHUP) Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-20 Yannik Völzke, Suzan Akbey, Daniel Löwen, Eberhard Daniel Pracht, Rüdiger Stirnberg, Vincent Gras, Nicolas Boulant, Moritz Zaiss, Tony Stöcker
PurposeChemical exchange saturation transfer (CEST) measurements at ultra‐high field (UHF) suffer from strong saturation inhomogeneity. Retrospective correction of this inhomogeneity is possible to some extent, but requires a time‐consuming repetition of the measurement. Here, we propose a calibration‐free parallel transmit (pTx)‐based saturation scheme that homogenizes the saturation over the imaging
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Local and whole‐body SAR in UHF body imaging: Implications for SAR matrix compression Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-20 Thomas M. Fiedler, Mark E. Ladd, Stephan Orzada
PurposeTransmit arrays for body imaging have characteristics of both volume and local transmit coils. This study evaluates two specific absorption rate (SAR) aspects, local and whole‐body SAR, of arrays for body imaging at 7 T and also for a 3 T birdcage.MethodsSimulations were performed for six antenna arrays at 7 T and one 3 T birdcage. Local SAR matrices and the whole‐body SAR matrix were computed
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A new approach for multislice spatiotemporal encoding MRI in a portable low-field system. Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-20 Yueqi Qiu,Suen Chen,Eddy Solomon,Changyue Wang,Sijie Zhong,Ke Dai,Hao Chen,Lucio Frydman,Zhiyong Zhang
PURPOSE Spatiotemporal encoding (SPEN) MRI offers a unique alternative to address image distortion problems in echo planar acquisition-based techniques, at portable low-field systems that lack multiple receiver coils. However, existing 2-π multislice SPEN schemes fail to keep consistent SNRs and contrasts with different numbers of slice settings. This work proposes a new multislice SPEN scheme (SPENms)
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Denoising of dual‐VENC PC‐MRI with large high/low VENC ratios Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-18 Jana Brunátová, Miriam Löcke, Sergio Uribe, Cristóbal Bertoglio
PurposeDual velocity encoding PC‐MRI can produce spurious artifacts when using high ratios of velocity encoding values (VENCs), limiting its ability to generate high‐quality images across a wide range of encoding velocities. This study aims to propose and compare dual‐VENC correction methods for such artifacts.Theory and MethodsTwo denoising approaches based on spatiotemporal regularization are proposed
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Comparison of 3D UTE free‐breathing lung MRI with hyperpolarized 129Xe MRI in pediatric cystic fibrosis Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-17 Samal Munidasa, Brandon Zanette, Marie‐Pier Dumas, Wallace Wee, Sharon Braganza, Daniel Li, Felix Ratjen, Giles Santyr
PurposeTo compare phase‐resolved functional lung (PREFUL) regional ventilation derived from a free breathing 3D UTE radial MRI acquisition to hyperpolarized 129Xe‐MRI (Xe‐MRI), conventional 2D multi‐slice PREFUL MRI, and pulmonary function tests in pediatric cystic fibrosis (CF) lung disease.MethodsFree‐breathing 3D UTE and 2D multi‐slice 1H MRI as well as Xe‐MRI were acquired in 12 stable pediatric
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Retrospective motion correction for cardiac multi‐parametric mapping with dictionary matching‐based image synthesis and a low‐rank constraint Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-17 Haiyang Chen, Yixin Emu, Juan Gao, Zhuo Chen, Ahmed Aburas, Chenxi Hu
PurposeTo develop a model‐based motion correction (MoCo) method that does not need an analytical signal model to improve the quality of cardiac multi‐parametric mapping.MethodsThe proposed method constructs a hybrid loss that includes a dictionary‐matching loss and a signal low‐rankness loss, where the former registers the multi‐contrast original images to a set of motion‐free synthetic images and
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Accelerated CEST imaging through deep learning quantification from reduced frequency offsets Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-13 Karandeep Cheema, Pei Han, Hsu‐Lei Lee, Yibin Xie, Anthony G. Christodoulou, Debiao Li
PurposeTo shorten CEST acquisition time by leveraging Z‐spectrum undersampling combined with deep learning for CEST map construction from undersampled Z‐spectra.MethodsFisher information gain analysis identified optimal frequency offsets (termed “Fisher offsets”) for the multi‐pool fitting model, maximizing information gain for the amplitude and the FWHM parameters. These offsets guided initial subsampling
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4D flow MRI velocity uncertainty quantification Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-13 Sean M. Rothenberger, Jiacheng Zhang, Michael Markl, Bruce A. Craig, Pavlos P. Vlachos, Vitaliy L. Rayz
PurposeAn automatic method is presented for estimating 4D flow MRI velocity measurement uncertainty in each voxel. The velocity distance (VD) metric, a statistical distance between the measured velocity and local error distribution, is introduced as a novel measure of 4D flow MRI velocity measurement quality.MethodsThe method uses mass conservation to assess the local velocity error variance and the
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An Eulerian formulation for the computational modeling of phase‐contrast MRI Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-13 Tomohiro Otani, Tetsuro Sekine, Yu Sato, Ellen Cavalcante Alves, Shigeo Wada
PurposeComputational simulation of phase‐contrast MRI (PC‐MRI) is an attractive way to physically interpret properties and errors in MRI‐reconstructed flow velocity fields. Recent studies have developed PC‐MRI simulators that solve the Bloch equation, with the magnetization transport being modeled using a Lagrangian approach. Because this method expresses the magnetization as spatial distribution of
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Accelerated model‐based T1, T2* and proton density mapping using a Bayesian approach with automatic hyperparameter estimation Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-13 Shuai Huang, James J. Lah, Jason W. Allen, Deqiang Qiu
PurposeTo achieve automatic hyperparameter estimation for the model‐based recovery of quantitative MR maps from undersampled data, we propose a Bayesian formulation that incorporates the signal model and sparse priors among multiple image contrasts.TheoryWe introduce a novel approximate message passing framework “AMP‐PE” that enables the automatic and simultaneous recovery of hyperparameters and quantitative
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Comparative analysis of in situ and ex situ postmortem brain MRI: Evaluating volumetry, DTI, and relaxometry Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-09 Dominique Neuhaus, Thomas Rost, Tanja Haas, Maria Janina Wendebourg, Katja Schulze, Regina Schlaeger, Eva Scheurer, Claudia Lenz
PurposeTo compare postmortem in situ with ex situ MRI parameters, including volumetry, diffusion tensor imaging (DTI), and relaxometry for assessing methodology‐induced alterations, which is a crucial prerequisite when performing MRI biomarker validation.MethodsMRI whole‐brain scans of five deceased patients with amyotrophic lateral sclerosis were performed at 3 T. In situ scans were conducted within
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Spherical echo‐planar time‐resolved imaging (sEPTI) for rapid 3D quantitative T2* and susceptibility imaging Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-09 Nan Wang, Congyu Liao, Xiaozhi Cao, Mark Nishimura, Yannick W. E. Brackenier, Mahmut Yurt, Mengze Gao, Daniel Abraham, Cagan Alkan, Siddharth Srinivasan Iyer, Zihan Zhou, Hwihun Jeong, Adam Kerr, Justin P. Haldar, Kawin Setsompop
PurposeTo develop a 3D spherical EPTI (sEPTI) acquisition and a comprehensive reconstruction pipeline for rapid high‐quality whole‐brain submillimeter and QSM quantification.MethodsFor the sEPTI acquisition, spherical k‐space coverage is utilized with variable echo‐spacing and maximum kx ramp‐sampling to improve efficiency and signal incoherency compared to existing EPTI approaches. For reconstruction
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Particle‐based MR modeling with diffusion, microstructure, and enzymatic reactions Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-09 Dylan Archer Dingwell, Charles H. Cunningham
PurposeTo develop a novel particle‐based in silico MR model and demonstrate applications of this model to signal mechanisms which are affected by the spatial organization of particles, including metabolic reaction kinetics, microstructural effects on diffusion, and radiofrequency (RF) refocusing effects in gradient‐echo sequences.MethodsThe model was developed by integrating a forward solution of the
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Rational approximation of golden angles: Accelerated reconstructions for radial MRI Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-09 Nick Scholand, Philip Schaten, Christina Graf, Daniel Mackner, H. Christian M. Holme, Moritz Blumenthal, Andrew Mao, Jakob Assländer, Martin Uecker
PurposeTo develop a generic radial sampling scheme that combines the advantages of golden ratio sampling with simplicity of equidistant angular patterns. The irrational angle between consecutive spokes in golden ratio‐based sampling schemes enables a flexible retrospective choice of temporal resolution, while preserving good coverage of k‐space for each individual bin. Nevertheless, irrational increments
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Optimization of 1H‐MRS methods for large‐volume acquisition of low‐concentration downfield resonances at 3 T and 7 T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-09 Neil E. Wilson, Mark A. Elliott, Ravi Prakash Reddy Nanga, Sophia Swago, Walter R. Witschey, Ravinder Reddy
PurposeThis goal of this study was to optimize spectrally selective 1H‐MRS methods for large‐volume acquisition of low‐concentration metabolites with downfield resonances at 7 T and 3 T, with particular attention paid to detection of nicotinamide adenine dinucleotide (NAD+) and tryptophan.MethodsSpectrally selective excitation was used to avoid magnetization‐transfer effects with water, and various
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Multicenter, multivendor validation of liver quantitative susceptibility mapping in patients with iron overload at 1.5 T and 3 T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-06 Collin J. Buelo, Julia Velikina, Lu Mao, Ruiyang Zhao, Qing Yuan, Mounes Aliyari Ghasabeh, Stefan Ruschke, Dimitrios C. Karampinos, David T. Harris, Ryan J. Mattison, Michael R. Jeng, Ivan Pedrosa, Ihab R. Kamel, Shreyas Vasanawala, Takeshi Yokoo, Scott B. Reeder, Diego Hernando
PurposeTo evaluate the repeatability and reproducibility of QSM of the liver via single breath‐hold chemical shift–encoded MRI at both 1.5 T and 3 T in a multicenter, multivendor study in subjects with iron overload.MethodsThis prospective study included four academic medical centers with three different MRI vendors at 1.5 T and 3 T. Subjects with known or suspected liver iron overload underwent multi‐echo
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Motion and temporal B0‐shift corrections for QSM and R2* mapping using dual‐echo spiral navigators and conjugate‐phase reconstruction Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-05 Yuguang Meng, Jason W. Allen, Vahid Khalilzad Sharghi, Deqiang Qiu
PurposeTo develop an efficient navigator‐based motion and temporal B0‐shift correction technique for 3D multi‐echo gradient‐echo (ME‐GRE) MRI for quantitative susceptibility mapping (QSM) and mapping.Theory and MethodsA dual‐echo 3D stack‐of‐spiral navigator was designed to interleave with the Cartesian multi‐echo gradient‐echo acquisitions, allowing the acquisition of both low‐echo and high‐echo time
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Joint learning of nonlinear representation and projection for fast constrained MRSI reconstruction Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-05 Yahang Li, Loreen Ruhm, Zepeng Wang, Ruiyang Zhao, Aaron Anderson, Paul Arnold, Graham Huesmann, Anke Henning, Fan Lam
PurposeTo develop and evaluate a novel method for computationally efficient reconstruction from noisy MR spectroscopic imaging (MRSI) data.MethodsThe proposed method features (a) a novel strategy that jointly learns a nonlinear low‐dimensional representation of high‐dimensional spectroscopic signals and a neural‐network‐based projector to recover the low‐dimensional embeddings from noisy/limited data;
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Automated MRI‐based segmentation of intracranial arterial calcification by restricting feature complexity Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Xin Wang, Gador Canton, Yin Guo, Kaiyu Zhang, Halit Akcicek, Ebru Yaman Akcicek, Thomas Hatsukami, Jin Zhang, Beibei Sun, Huilin Zhao, Yan Zhou, Linda Shapiro, Mahmud Mossa‐Basha, Chun Yuan, Niranjan Balu
PurposeTo develop an automated deep learning model for MRI‐based segmentation and detection of intracranial arterial calcification.MethodsA novel deep learning model under the variational autoencoder framework was developed. A theoretically grounded dissimilarity loss was proposed to refine network features extracted from MRI and restrict their complexity, enabling the model to learn more generalizable
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Quantitative mapping of renal oxygen consumption using pseudo‐continuous arterial spin labeling and quantitative susceptibility mapping in humans Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Yujin Jung, Hyun‐Seo Ahn, Sung‐Hong Park
PurposeTo propose a new method for quantitatively mapping the renal metabolic rate of oxygen (RMRO2) and to evaluate the proposed method using a caffeine challenge.Theory and MethodsPseudo‐continuous arterial spin labeling (pCASL) and QSM sequences were used to obtain MR images in the kidney. Six healthy volunteers were scanned on caffeine and control days. The pCASL and QSM images were registered
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High‐quality FLORET UTE imaging for clinical translation Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Matthew M. Willmering, Guruprasad Krishnamoorthy, Ryan K. Robison, Jens T. Rosenberg, Jason C. Woods, James G. Pipe
PurposeTo develop a robust 3D ultrashort‐TE (UTE) protocol that can reproducibly provide high‐quality images, assessed by the ability to yield clinically diagnostic images, and is suitable for clinical translation.Theory and MethodsBuilding on previous work, a UTE sampled with Fermat looped orthogonally encoded trajectories (FLORET) was chosen as a starting point due to its shorter, clinically reasonable
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Improving standardization and accuracy of in vivo omega plot exchange parameter determination using rotating‐frame model‐based fitting of quasi‐steady‐state Z‐spectra Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Julius Juhyun Chung, Hahnsung Kim, Yang Ji, Dongshuang Lu, Iris Y. Zhou, Phillip Zhe Sun
PurposeAlthough Ω‐plot‐driven quantification of in vivo amide exchange properties has been demonstrated, differences in scan parameters may complicate the fidelity of determination. This work systematically evaluated the use of quasi‐steady‐state (QUASS) Z‐spectra reconstruction to standardize in vivo amide exchange quantification across acquisition conditions and further determined it in vivo.MethodsSimulation
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A diffusion‐prepared reduced FOV sequence for prostate MRI near metallic implants Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Philip K. Lee, Jeremiah J. Hess, Andrew A. Gomella, Andreas M. Loening, Brian A. Hargreaves
PurposeTo enable diffusion weighted imaging in prostate patients with metallic total hip replacements in clinically feasible scan times for prostate cancer screening, and avoid distortion and dropout artifacts present in the conventionally used Echo Planar Imaging (EPI).MethodsA reduced field of view (FOV) diffusion‐prepared sequence that is robust to the B inhomogeneities produced by total hip replacements
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Three contrasts in 3 min: Rapid, high‐resolution, and bone‐selective UTE MRI for craniofacial imaging with automated deep‐learning skull segmentation Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Brian‐Tinh Duc Vu, Nada Kamona, Yohan Kim, Jinggang J. Ng, Brandon C. Jones, Felix W. Wehrli, Hee Kwon Song, Scott P. Bartlett, Hyunyeol Lee, Chamith S. Rajapakse
PurposeUltrashort echo time (UTE) MRI can be a radiation‐free alternative to CT for craniofacial imaging of pediatric patients. However, unlike CT, bone‐specific MR imaging is limited by long scan times, relatively low spatial resolution, and a time‐consuming bone segmentation workflow.MethodsA rapid, high‐resolution UTE technique for brain and skull imaging in conjunction with an automatic segmentation
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A 32‐channel high‐impedance honeycomb‐shaped receive array for temporal lobes exploration at 11.7T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Paul‐François Gapais, Michel Luong, Eric Giacomini, Jules Guillot, Elias Djaballah, Shajan Gunamony, Son Chu, Sajad Hosseinnezhadian, Alexis Amadon
PurposeThe newly operational 11.7T Iseult scanner provides an improved global SNR in the human brain. This gain in SNR can be pushed even further locally by designing region‐focused dense receive arrays. The temporal lobes are particularly interesting to neuroscientists as they are associated with language and concept recognition. Our main goal was to maximize the SNR in the temporal lobes and provide
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QRAGE—Simultaneous multiparametric quantitative MRI of water content, T1, T2*, and magnetic susceptibility at ultrahigh field strength Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Markus Zimmermann, Zaheer Abbas, Yannic Sommer, Alexander Lewin, Shukti Ramkiran, Jörg Felder, Wieland A. Worthoff, Ana‐Maria Oros‐Peusquens, Seong Dae Yun, N. Jon Shah
PurposeTo introduce quantitative rapid gradient‐echo (QRAGE), a novel approach for the simultaneous mapping of multiple quantitative MRI parameters, including water content, T1, T2*, and magnetic susceptibility at ultrahigh field strength.MethodsQRAGE leverages a newly developed multi‐echo MPnRAGE sequence, facilitating the acquisition of 171 distinct contrast images across a range of inversion and
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Fast, automated, real‐time 3D passive balloon catheter tracking during MRI‐guided cardiac catheterization using orthogonal projection imaging and real‐time image‐based catheter detection Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Grzegorz T. Kowalik, Eric Kerfoot, Karl Kunze, Radhouene Neji, Tracy Moon, Nina Mellor, Reza Razavi, Kuberan Pushparajah, Sébastien Roujol
PurposeMRI‐guidance of cardiac catheterization is currently performed using one or multiple 2D imaging planes, which may be suboptimal for catheter navigation, especially in patients with complex anatomies. The purpose of the work was to develop a robust real‐time 3D catheter tracking method and 3D visualization strategy for improved MRI‐guidance of cardiac catheterization procedures.MethodsA fast
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Spiral 3DREAM sequence for fast whole‐brain B1 mapping Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Svenja Niesen, Marten Veldmann, Philipp Ehses, Tony Stöcker
PurposeThis work demonstrates a new variant of the 3DREAM sequence for whole‐brain mapping employing a three‐dimensional (3D) stack‐of‐spirals readout. The spiral readout reduces the echo train length after the STEAM preparation in order to overcome the significant blurring in STE* images due to the decreasing STE* signal with each excitation pulse.MethodsThe 3DREAM sequence rapidly acquires two contrasts
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T1 and T2 measurements across multiple 0.55T MRI systems using open‐source vendor‐neutral sequences Magn. Reson. Med. (IF 3.0) Pub Date : 2024-09-02 Kathryn E. Keenan, Bilal Tasdelen, Ahsan Javed, Rajiv Ramasawmy, Rudy Rizzo, Michele N. Martin, Karl F. Stupic, Nicole Seiberlich, Adrienne E. Campbell‐Washburn, Krishna S. Nayak
PurposeTo compare T1 and T2 measurements across commercial and prototype 0.55T MRI systems in both phantom and healthy participants using the same vendor‐neutral pulse sequences, reconstruction, and analysis methods.MethodsStandard spin echo measurements and abbreviated protocol measurements of T1, B1, and T2 were made on two prototype 0.55 T systems and two commercial 0.55T systems using an ISMRM/NIST
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On the impact of B0 shimming algorithms on single‐voxel MR spectroscopy Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-27 Behrouz Vejdani Afkham, Eva Alonso‐Ortiz
PurposeTo assess the impact of different B0 shimming algorithms on MRS.MethodsB0 field maps and single‐voxel MR spectroscopy were acquired in the prefrontal cortex of five volunteers at 3 T using five different B0 shimming approaches. B0 shimming was achieved using Siemens' proprietary shim algorithm, in addition to the Pseudo‐Inverse (PI), Quadratic Programming (QuadProg), Least Squares (LSq), and
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Run‐time motion and first‐order shim control by expanded servo navigation Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-27 Malte Riedel, Thomas Ulrich, Klaas P. Pruessmann
PurposeTo provide a navigator‐based run‐time motion and first‐order field correction for three‐dimensional human brain imaging with high precision, minimal calibration and acquisition, and fast processing.MethodsA complex‐valued linear perturbation model with feedback control is extended to estimate and correct for gradient shim fields using orbital navigators (2.3 ms). Two approaches for sensitizing
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Reproducible and highly miniaturized bazooka RF Balun using a printed capacitor Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-27 Ming Lu, Yijin Yang, Shuyang Chai, Xinqiang Yan
PurposeThere is currently a strong trend in developing RF coils that are high‐density, lightweight, and highly flexible. In addition to the resonator structure of the RF coil itself, the balun or cable trap circuit serves as another essential element in the functionality and sensitivity of RF coils. This study explores the development and application of reproducible highly miniaturized baluns in RF
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CineVN: Variational network reconstruction for rapid functional cardiac cine MRI Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-27 Marc Vornehm, Jens Wetzl, Daniel Giese, Florian Fürnrohr, Jianing Pang, Kelvin Chow, Rolf Gebker, Rizwan Ahmad, Florian Knoll
PurposeTo develop a reconstruction method for highly accelerated cardiac cine MRI with high spatiotemporal resolution and low temporal blurring, and to demonstrate accurate estimation of ventricular volumes and myocardial strain in healthy subjects and in patients.MethodsThe proposed method, called CineVN, employs a spatiotemporal Variational Network combined with conjugate gradient descent for optimized
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XSIM: A structural similarity index measure optimized for MRI QSM Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-23 Carlos Milovic, Cristian Tejos, Javier Silva, Karin Shmueli, Pablo Irarrazaval
PurposeThe structural similarity index measure (SSIM) has become a popular quality metric to evaluate QSM in a way that is closer to human perception than RMS error (RMSE). However, SSIM may overpenalize errors in diamagnetic tissues and underpenalize them in paramagnetic tissues, resulting in biasing. In addition, extreme artifacts may compress the dynamic range, resulting in unrealistically high
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Gradient‐induced vibrations and motion‐induced Lenz effects on conductive nonmagnetic orthopedic implants in MRI Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-23 Luca Zilberti, Cristina Curreli, Alessandro Arduino, Umberto Zanovello, Fabio Baruffaldi, Oriano Bottauscio
PurposeTo quantify the extent of gradient‐induced vibrations, and the magnitude of motion‐induced displacement forces (“Lenz effect”), in conductive nonmagnetic orthopedic prostheses.MethodsThe investigation is carried out through numerical simulations, for a 3 T scanner. For gradient‐induced torques and vibrations, a knee and a shoulder implant are considered, at dB/dt equal to 42 T/s (rms). For motion‐induced
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Abdominal MR Multitasking for radiotherapy treatment planning: A motion‐resolved and multicontrast 3D imaging approach Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-22 Junzhou Chen, Anthony G. Christodoulou, Pei Han, Jiayu Xiao, Fei Han, Zhehao Hu, Nan Wang, Hui Han, Diane C. Ling, Eric L. Chang, Mary Feng, Jessica E. Scholey, Sophia Cui, Debiao Li, Wensha Yang, Zhaoyang Fan
PurposeRadiotherapy treatment planning (RTP) using MR has been used increasingly for the abdominal site. Multiple contrast weightings and motion‐resolved imaging are desired for accurate delineation of the target and various organs‐at‐risk and patient‐tailored planning. Current MR protocols achieve these through multiple scans with distinct contrast and variable respiratory motion management strategies
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3D MR fingerprinting for dynamic contrast‐enhanced imaging of whole mouse brain Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-22 Yuran Zhu, Guanhua Wang, Yuning Gu, Walter Zhao, Jiahao Lu, Junqing Zhu, Christina J. MacAskill, Andrew Dupuis, Mark A. Griswold, Dan Ma, Chris A. Flask, Xin Yu
PurposeQuantitative MRI enables direct quantification of contrast agent concentrations in contrast‐enhanced scans. However, the lengthy scan times required by conventional methods are inadequate for tracking contrast agent transport dynamically in mouse brain. We developed a 3D MR fingerprinting (MRF) method for simultaneous T1 and T2 mapping across the whole mouse brain with 4.3‐min temporal resolution
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Joint estimation of compartment‐specific T2 relaxation and tumor microstructure using multi‐TE IMPULSED MRI Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-22 Xiaoyu Jiang, Kevin D. Harkins, Jingping Xie, Jian Wang, Zhongliang Zu, John C. Gore, Junzhong Xu
PurposeThis study aims to assess how T2 heterogeneity biases IMPULSED‐derived metrics of tissue microstructure in solid tumors and evaluate the potential of estimating multi‐compartmental T2 and microstructural parameters simultaneously.MethodsThis study quantifies the impact of T2 relaxation on IMPULSED‐derived microstructural parameters using computer simulations and in vivo multi‐TE IMPULSED MRI
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Multiband accelerated 2D EPI for multi‐echo brain QSM at 3 T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-22 Oliver C. Kiersnowski, Patrick Fuchs, Stephen J. Wastling, Jannette Nassar, John S. Thornton, Karin Shmueli
PurposeData for QSM are typically acquired using multi‐echo 3D gradient echo (GRE), but EPI can be used to accelerate QSM and provide shorter acquisition times. So far, EPI‐QSM has been limited to single‐echo acquisitions, which, for 3D GRE, are known to be less accurate than multi‐echo sequences. Therefore, we compared single‐echo and multi‐echo EPI‐QSM reconstructions across a range of parallel imaging
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Three‐dimensional radial echo‐planar spectroscopic imaging for hyperpolarized 13C MRSI in vivo Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-22 Marcel Awenius, Helen Abeln, Melanie Müller, Vanessa L. Franke, Gino Rincon, Christin Glowa, Michaela Schmitt, Renate Bangert, Dominik Ludwig, Andreas B. Schmidt, Tristan A. Kuder, Mark E. Ladd, Peter Bachert, Philipp Biegger, Andreas Korzowski
PurposeTo demonstrate the feasibility of 3D echo‐planar spectroscopic imaging (EPSI) technique with rapid volumetric radial k‐space sampling for hyperpolarized (HP) 13C magnetic resonance spectroscopic imaging (MRSI) in vivo.MethodsA radial EPSI (rEPSI) was implemented on a 3 T clinical PET/MR system. To enable volumetric coverage, the sinusoidal shaped readout gradients per k‐t‐spoke were rotated
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Fast cardiac T1ρ,adiab mapping using slice‐selective adiabatic spin‐lock preparation pulses Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-19 Andrew Tyler, Karl Kunze, Radhouene Neji, Pier Giorgio Masci, Reza Razavi, Amedeo Chiribiri, Sébastien Roujol
PurposeMyocardial T1ρ mapping techniques commonly acquire multiple images in one breathhold to calculate a single‐slice T1ρ map. Recently, non‐selective adiabatic pulses have been used for robust spin‐lock preparation (T1ρ,adiab). The objective of this study was to develop a fast multi‐slice myocardial T1ρ,adiab mapping approach.MethodsThe proposed‐sequence reduces the number of breathholds required
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Improved visualization of intracranial distal arteries with multiple 2D slice dynamic ASL‐MRA and super‐resolution convolutional neural network Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-19 Yuriko Suzuki, Ioannis Koktzoglou, Ziyu Li, Peter Jezzard, Thomas Okell
PurposeTo develop a novel framework to improve the visualization of distal arteries in arterial spin labeling (ASL) dynamic MRA.MethodsThe attenuation of ASL blood signal due to the repetitive application of excitation RF pulses was minimized by splitting the acquisition volume into multiple thin 2D (M2D) slices, thereby reducing the exposure of the arterial blood magnetization to RF pulses while it
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Dixon‐based B0 self‐navigation in radial stack‐of‐stars multi‐echo gradient echo imaging Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-19 Jonathan Stelter, Kilian Weiss, Mingming Wu, Johannes Raspe, Philipp Braun, Christoph Zöllner, Dimitrios C. Karampinos
PurposeTo develop a Dixon‐based self‐navigation approach to estimate and correct temporal variations in radial stack‐of‐stars gradient echo imaging for quantitative body MRI.MethodsThe proposed method estimates temporal variations using a self‐navigator estimated by a graph‐cut‐based water‐fat separation algorithm on the oversampled k‐space center. The self‐navigator was employed to correct for phase
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Simultaneous frequency and phase corrections of single‐shot MRS data using cross‐correlation Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-19 Dinesh K. Deelchand
PurposeThe objective of this study was to propose a novel preprocessing approach to simultaneously correct for the frequency and phase drifts in MRS data using cross‐correlation technique.MethodsThe performance of the proposed method was first investigated at different SNR levels using simulation. Random frequency and phase offsets were added to a previously acquired STEAM human data at 7 T, simulating
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Improving Xenon‐129 lung ventilation image SNR with deep‐learning based image reconstruction Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-19 Neil J. Stewart, Jose de Arcos, Alberto M. Biancardi, Guilhem J. Collier, Laurie J. Smith, Graham Norquay, Helen Marshall, Anja C. S. Brau, R. Marc Lebel, Jim M. Wild
PurposeTo evaluate the feasibility and utility of a deep learning (DL)‐based reconstruction for improving the SNR of hyperpolarized 129Xe lung ventilation MRI.Methods129Xe lung ventilation MRI data acquired from patients with asthma and/or chronic obstructive pulmonary disease (COPD) were retrospectively reconstructed with a commercial DL reconstruction pipeline at five different denoising levels.
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Time‐division multiplexing (TDM) sequence removes bias in T2 estimation and relaxation‐diffusion measurements Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-13 Qiang Liu, Borjan Gagoski, Imam Ahmed Shaik, Carl‐Fredrik Westin, Elisabeth A. Wilde, Walter Schneider, Berkin Bilgic, William A. Grissom, Jon‐Fredrik Nielsen, Maxim Zaitsev, Yogesh Rathi, Lipeng Ning
PurposeTo compare the performance of multi‐echo (ME) and time‐division multiplexing (TDM) sequences for accelerated relaxation‐diffusion MRI (rdMRI) acquisition and to examine their reliability in estimating accurate rdMRI microstructure measures.MethodThe ME, TDM, and the reference single‐echo (SE) sequences with six TEs were implemented using Pulseq with single‐band (SB) and multi‐band 2 (MB2) acceleration
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RF shimming in the cervical spinal cord at 7 T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-13 Daniel Papp, Kyle M. Gilbert, Gaspard Cereza, Alexandre D'Astous, Nibardo Lopez‐Rios, Mathieu Boudreau, Marcus J. Couch, Pedram Yazdanbakhsh, Robert L. Barry, Eva Alonso‐Ortiz, Julien Cohen‐Adad
PurposeAdvancing the development of 7 T MRI for spinal cord imaging is crucial for the enhanced diagnosis and monitoring of various neurodegenerative diseases and traumas. However, a significant challenge at this field strength is the transmit field inhomogeneity. Such inhomogeneity is particularly problematic for imaging the small, deep anatomical structures of the cervical spinal cord, as it can
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B1‐MRF: Large dynamic range MRF‐based absolute B1+ mapping in the human body at 7T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-12 Max Lutz, Christoph Stefan Aigner, Sebastian Flassbeck, Felix Krueger, Constance G. F. Gatefait, Christoph Kolbitsch, Berk Silemek, Frank Seifert, Tobias Schaeffter, Sebastian Schmitter
PurposeThis study aims to map the transmit magnetic field () in the human body at 7T using MR fingerprinting (MRF), with a focus on achieving high accuracy and precision across a large dynamic range, particularly at low flip angles (FAs).MethodsA FLASH‐based MRF sequence (B1‐MRF) with high sensitivity was developed. Phantom and in vivo abdominal imaging were performed at 7T, and the results were compared
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Fast and motion‐robust saturation transfer MRI with inherent B0 correction using rosette trajectories and compressed sensing Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-12 Sultan Z. Mahmud, Munendra Singh, Peter van Zijl, Hye‐Young Heo
PurposeTo implement rosette readout trajectories with compressed sensing reconstruction for fast and motion‐robust CEST and magnetization transfer contrast imaging with inherent correction of B0 inhomogeneity.MethodsA pulse sequence was developed for fast saturation transfer imaging using a stack of rosette trajectories with a higher sampling density near the k‐space center. Each rosette lobe was segmented
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DeepEMC‐T2 mapping: Deep learning–enabled T2 mapping based on echo modulation curve modeling Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-12 Haoyang Pei, Timothy M. Shepherd, Yao Wang, Fang Liu, Daniel K. Sodickson, Noam Ben‐Eliezer, Li Feng
PurposeEcho modulation curve (EMC) modeling enables accurate quantification of T2 relaxation times in multi‐echo spin‐echo (MESE) imaging. The standard EMC‐T2 mapping framework, however, requires sufficient echoes and cumbersome pixel‐wise dictionary‐matching steps. This work proposes a deep learning version of EMC‐T2 mapping, called DeepEMC‐T2 mapping, to efficiently estimate accurate T2 maps from
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Reproducibility of intravoxel incoherent motion quantification in the liver across field strengths and gradient hardware Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-09 Gregory Simchick, Timothy J. Allen, Diego Hernando
PurposeTo evaluate reproducibility and interlobar agreement of intravoxel incoherent motion (IVIM) quantification in the liver across field strengths and MR scanners with different gradient hardware.MethodsCramer‐Rao lower bound optimization was performed to determine optimized monopolar and motion‐robust 2D (b‐value and first‐order motion moment [M1]) IVIM‐DWI acquisitions. Eleven healthy volunteers
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Water phase transition and signal nulling in 3D dual‐echo adiabatic inversion‐recovery UTE (IR‐UTE) imaging of myelin Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-09 Jiyo S. Athertya, Soo Hyun Shin, Bhavsimran Singh Malhi, James Lo, Sam Sedaghat, Hyungseok Jang, Yajun Ma, Jiang Du
PurposeThe semisolid myelin sheath has very fast transverse relaxation and is invisible to conventional MRI sequences. UTE sequences can detect signal from myelin. The major challenge is the concurrent detection of various water components.MethodsThe inversion recovery (IR)–based UTE (IR‐UTE) sequence employs an adiabatic inversion pulse to invert and suppress water magnetizations. TI plays a key role
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In vivo MRI of hyperpolarized silicon‐29 nanoparticles Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-09 Grzegorz Kwiatkowski, Gevin von Witte, Alexander Däpp, Jovana Kocic, Bodo Hattendorf, Matthias Ernst, Sebastian Kozerke
PurposeThe objective of the present work was to test the feasibility of in vivo imaging of hyperpolarized 50‐nm silicon‐29 (29Si) nanoparticles.MethodsCommercially available, crystalline 50‐nm nanoparticles were hyperpolarized using dynamic polarization transfer via the endogenous silicon oxide–silicon defects without the addition of exogenous radicals. Phantom experiments were used to quantify the
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Fast and silent MRI using nonlinear gradient fields at the ultrasonic gradient switching frequency of 20 kHz with a Point Spread Function framework reconstruction Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-05 Michael J. B. McGrory, Edwin Versteeg, Alessandro Sbrizzi, Cornelis A. T. van den Berg, Dennis Klomp, Jeroen C. W. Siero
PurposeTo demonstrate the feasibility of using a nonlinear gradient field for spatial encoding at the ultrasonic switching frequency of 20 kHz and present a framework to reconstruct data acquired in this way.MethodsNonlinear encoding at 20 kHz was realized by using a single‐axis silent gradient insert for imaging in the periphery, that, is the nonlinear region, of the gradient field. The gradient insert
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Deciphering adiabatic rotating frame relaxometry in biological tissues Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-05 Yuxi Pang
PurposeThis work aims to unravel the intricacies of adiabatic rotating frame relaxometry in biological tissues.Theory and MethodsThe classical formalisms of dipolar relaxation and were systematically analyzed for water molecules reorienting on “fast” and “slow” timescales. These two timescales are, respectively, responsible for the absence and presence of dispersion. A time‐averaged or over an adiabatic
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Slice‐specific B1+ shimming improves the repeatability of multishot DWI at 7 T Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-02 Belinda Ding, Sydney Nicole Williams, Iulius Dragonu, Patrick Liebig, Sarah Allwood‐Spiers, Paul McElhinney, Shajan Gunamony, Natasha Fullerton, David Andrew Porter
PurposeCompared with lower field strengths, DWI at 7 T faces the combined challenges of increased distortion and blurring due to B0 inhomogeneity, and increased signal dropouts due to B1+ inhomogeneity. This study addresses the B1+ limitations using slice‐specific static parallel transmission (pTx) in a multi‐shot, readout‐segmented EPI diffusion imaging sequence.MethodsDWI was performed in 7 healthy
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Unraveling contributions to the Z‐spectrum signal at 3.5 ppm of human brain tumors Magn. Reson. Med. (IF 3.0) Pub Date : 2024-08-01 Hye‐Young Heo, Munendra Singh, Sultan Z. Mahmud, Lindsay Blair, David Olayinka Kamson, Jinyuan Zhou
PurposeTo evaluate the influence of the confounding factors, direct water saturation (DWS), and magnetization transfer contrast (MTC) effects on measured Z‐spectra and amide proton transfer (APT) contrast in brain tumors.MethodsHigh‐grade glioma patients were scanned using an RF saturation‐encoded 3D MR fingerprinting (MRF) sequence at 3 T. For MRF reconstruction, a recurrent neural network was designed