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Noa van der Knaap^1,2,3, Paulien H.M. Voorter^1,3, Marcel J.H. Ariës^1,2, and Jacobus F.A. Jansen^1,3,4
1School for Mental Health & Neuroscience, Maastricht University, Maastricht, Netherlands, ²Department of Intensive Care, Maastricht University Medical Center, Maastricht, Netherlands, ³Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands, ⁴Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands

Keywords: Parallel Imaging, Parallel Imaging

The MultiBand (MB) imaging technique can reduce scan time considerably, which can be especially relevant for clinical application of techniques with extensive scan protocols, such as intravoxel incoherent motion (IVIM) imaging. However, quantitative IVIM parameter estimates may be affected by the use of MB. This study is a first step to assess the comparability between IVIM acquisitions with and without MB, which has considerable implications for interpretation of IVIM results across different datasets.

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Jamie Near^1,2, Vorapin Chinchalongporn³, Rajshree Ghosh Biswas⁴, Maggie Wu¹, Martin Wilson⁵, Andre Simpson⁴, and Carol Schuurmans^3
1Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, ²Medical Biophysics, University of Toronto, Toronto, ON, Canada, ³Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada, ⁴Chemistry, University of Toronto, Toronto, ON, Canada, ⁵University of Birmingham, Birmingham, United Kingdom

Keywords: Data Acquisition, Tissue Characterization, NMR

 Cerebral organoids are self-organizing three-dimensional clusters of brain tissue, derived from human pluripotent stem cells.  A new and rapidly advancing technology, cerebral organoids serve as an important model system for human brain research.  In this study, we used high-resolution magic angle spinning (HR-MAS) NMR to characterize the neurochemical profile of ~100-day old cerebral organoids. High-quality spectra were obtained with excellent spectral resolution.  More than 17 metabolites were detected, including many resonances commonly observed in the brain in vivo (e.g. choline, creatine, glutamate, GABA, etc.).  Notably, NAA was absent.  Future work will assess cerebral organoids at later stages of maturity.

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Kurt G Schilling¹, Kristin P O'Grady¹, Anna J.E. Combes¹, Grace Sweeney¹, Logan Prock¹, Julien Cohen Adad², Bennett A Landman³, and Seth A Smith^1
1Vanderbilt University Medical Center, Nashville, TN, United States, ²Polytechnique Montreal, Montreal, QC, Canada, ³Vanderbilt University, Nashville, TN, United States

Keywords: Data Acquisition, Spinal Cord

Cardiac triggering is commonly used in diffusion MRI protocols of the cervical spinal cord to reduce cardiac-related motion. However, this dramatically increases scan time and can limit high angular resolution multi-shell experiments. We test whether advances in preprocessing motion correction and fitting procedures may overcome cardiac-related motion artifacts. We find that removing cardiac triggering regains significant scan time with no increase in prevalence of artifacts, while providing similar quantitative indices with comparable reproducibility. In summary, removing cardiac triggering for cervical spinal cord diffusion saves time without sacrificing image quality. 

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Martijn Nagtegaal^1,2, Simon Konstandin³, Daniel Hoinkiss³, Nicolas Gross-Weege⁴, Volkmar Schulz^3,4, Matthias Günther^3,5,6, and Matthias J.P. van Osch^2
1Department of Imaging Physics, Delft University of Technology, Delft, Netherlands, ²C.J. Gorter MRI Center, Radiology Department, Leiden University Medical Center, Leiden, Netherlands, ³Imaging Physics, Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany, ⁴RWTH Aachen, Aachen, Germany, ⁵mediri GmbH, Heidelberg, Germany, ⁶University of Bremen, Bremen, Germany

Keywords: Pulse Sequence Design, Pulse Sequence Design, Vendor independent pulse programming

Pulse sequence design and development in MR is currently hindered by the possibilities to freely share pulse sequences and test these on scanners of different vendors. Vendor independent pulse programming environments provide a shareable, open, and reproducible way of pulse sequence development. An important step in this is the support on scanners of all main vendors of these protocols. In this work we show for the first time the execution of gammaSTAR imaging protocols on a Philips scanner. The obtained FLASH and RARE based images are very similar to the images obtained using the vendor’s implementation.

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Alexander JS Beckett^1,2, An T Vu^3,4, Samantha J Ma⁵, Essa Yacoub⁶, and David A Feinberg^1,2
1Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States, ²Advanced MRI Technologies, Sebastopol, CA, United States, ³Radiology, University of California, San Francisco, CA, United States, ⁴San Francisco Veteran Affairs Health Care System, San Francisco, CA, United States, ⁵Siemens Medical Solutions USA, Inc., Malvern, PA, United States, ⁶Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

Keywords: Data Acquisition, fMRI

Multi-echo (ME) EPI can increase BOLD sensitivity and reduce signal drop-out compared with standard gradient echo (GE) EPI, however spatial resolution and number of echo images are limited by the echo train length of each image. The powerful gradients on the NexGen 7T scanner allow for shorter echo spacing, and hence a greater number of echoes collected at high-resolution (1.6mm isotropic) as compared to standard 7T systems. ME-EPI collected at these resolutions can be separated into TE-dependent and TE-independent components using ME-ICA, showing promise for ME functional connectivity studies at 7T.

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Siyuan Hu¹, Debra McGivney¹, Zhilang Qiu¹, and Dan Ma^1
1Case Western Reserve University, Cleveland, OH, United States

Keywords: Pulse Sequence Design, MR Fingerprinting

It is critical to characterize the dominating systematic errors caused by undersampling and field inhomogeneity to design robust MRF scans. However, characterizing such errors by direct simulations of aliasing artifacts is computationally expensive and impractical for sequence optimization for multi-dimensional MRF (mdMRF) scans with higher dimensions. We propose the Systematic Error Index, a model to characterize systematic errors with high computational efficiency. We demonstrate accurate and robust in vivo results from the optimized MRF and mdMRF scans obtained from the proposed SEI-based optimization framework. 

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Anke Christenhusz¹, Frank F.J. Simonis¹, Bennie ten Haken¹, Justin C.A. te Wildt¹, Sadaf Sadamzadeh¹, Anneriet E. Dassen², and Lejla Alic^1
1Magnetic Detection and Imaging, University of Twente, Enschede, Netherlands, ²Surgery, Medisch Spectrum Twente, Enschede, Netherlands

Keywords: Data Acquisition, Cancer, Lymph node, low-field, portable scanner

Sentinel lymph node (LN) biopsy facilitated by magnetic nanoparticles (MNP) is introduced for breast cancer patients eligible for breast conserving surgery. As m1etastatic depositions potentially introduce changes in heterogeneity of MNP-enhanced MRI, a portable low-field MRI scanner can be used for ex vivo perioperative LN staging. Therefore, we assessed the changes in T1w, T2w and STIR images due to iron deposition in LN. 2Clinically relevant LN segments, such as fat and iron depositions, identified in the pathology images, were also observable in MR scans.

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Pradeep Kumar Gupta¹, Stepan Orlovskiy¹, Jyoti S Tomar¹, Fernando Arias-Mendoza¹, David S. Nelson¹, Stephen Pickup¹, Alexander A. Shestov¹, Dennis B. Leeper², Jerry D Glickson¹, and Kavindra Nath^1
1Departments of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, United States

Keywords: Data Acquisition, Cancer

In vivo ¹H/³¹P MRS were used to monitor the effects of Kinase Inhibitor (KI) therapy in two metabolically different human melanoma xenografts models. Our goal is to determine the metabolic changes in human melanoma xenograft models when treated with two KIs, a BRAF and a MEK inhibitor. KI combination is more effective than single-drug therapy. Differences in relative levels of metabolites and bioenergetics between two human melanoma xenografts models may produce differential therapeutic responses to BRAF and MEK inhibitors. In melanoma, metabolic changes in response to targeted kinase inhibitor therapy occur rapidly and are connected to subsequent tumor response.

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Chaithya G R^1,2, Guillaume Daval-Frérot^1,2,3, Aurélien Massire³, Alexandre Vignaud¹, and Philippe Ciuciu^1,2
1Neurospin, CEA Paris Saclay, Gif-sur-Yvette, 91191, France, ²Inria, MIND, Palaiseau, 91120, France, ³Siemens Healthineers, Saint-Denis, 93210, France

Keywords: New Trajectories & Spatial Encoding Methods, Brain

Cartesian sampling can acquire a given k-space region with minimum redundancy, while non-Cartesian sampling can help achieve a larger k-space coverage. Through generalized affine constraints in SPARKLING and an adapted target sampling density, for the first time non-Cartesian and Cartesian sampling are merged within same trajectory, giving the best of both worlds. With Gridding of Low Frequencies (GoLF), we get SPARKLING k-space trajectories which carry out Cartesian sampling at the center of k-space. This approach paves the way for designing new kind of compound sampling patterns, which enforces Cartesian and non-Cartesian sampling within the same trajectory.

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Jun Zhao^1,2, Yupeng Cao¹, Weinan Tang³, Quelu Chen⁴, Wentao Liu¹, and Dong Han^1
1Key Laboratory of Biological Effects and Safety, National Center for Nanoscience and Technology, beijing, China, ²School of Future Technology, University of Chinese Academy of Sciences, Beijing, China, ³Wandong Medical Inc, Beijing, China, Beijing, China, ⁴Department of Radiology, Wenzhou Central Hospital, Affiliated Dingli Clinical Institute of Wenzhou Medical University, Wenzhou, China

Keywords: Pulse Sequence Design, Lung, hard pulse encoding, variable TE, frequency modulation, spiral

Due to its short T₂^* value and low proton density, MR imaging of the lung is quite challenging. Recently, ultra-short echo time (UTE) techniques, such as stack-of-spiral, were used to conduct lung MRI with good image quality. Here, based on stack-of-spiral, a frequency modulation hard pulse encoding (HAPEN) 3D UTE was proposed to optimize the echo time of different phase encoding steps in the slice direction. As a result, HAPEN can achieve shorter TE and get better SNR in human lung MRI compared to the traditional stack-of-spiral UTE sequence.

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Dahan Kim¹, Tzu Cheng Chao¹, Dinghui Wang¹, and James G Pipe^1
1Department of Radiology, Mayo Clinic, Rochester, MN, United States

Keywords: New Trajectories & Spatial Encoding Methods, New Trajectories & Spatial Encoding Methods, Spiral, FLAIR, LQ

We describe our novel T2W 2D FLAIR sequence whose temporal and SNR efficiencies are maximized by (1) an efficient IR acquisition that minimizes sequence deadtime and (2) localized quadratic encoding which eliminates SNR-inefficiencies of multi-pass 2D acquisitions. These improvements allowed our FLAIR scan to shorten the scan time while achieving higher SNR than standard SE and 2D-TSE scans of identical/equivalent scan time.

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Jörn Huber¹, Daniel Christopher Hoinkiss¹, Christina Plump^2,3, Christoph Lüth^2,3, Rolf Drechsler^2,3, and Matthias Günther^1,4,5
1Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany, ²German Research Center for Artificial Intelligence DFKI, Bremen, Germany, ³University of Bremen, Bremen, Germany, ⁴Faculty 1 (Physics/Electrical Engineering), University of Bremen, Bremen, Germany, ⁵mediri GmbH, Heidelberg, Germany

Keywords: Pulse Sequence Design, Software Tools

This work demonstrates the formulation of MRI sequences in a high-level Domain Specific Language (DSL). The DSL approach reduces the complexity of MR sequence programming and enables optimization of preconfigured DSL parameters using MR simulations. Finally, using the gammaSTAR framework, DSL sequences can be directly run on real MR scanners.

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Julian Bertini¹, Mira Liu¹, Chisondi Simba Warioba¹, Yu Fen Chen², and Timothy Carroll^1
1University of Chicago, Chicago, IL, United States, ²Department of Radiology, Northwestern Feinberg School of Medicine, Chicago, IL, United States

Keywords: Pulse Sequence Design, Phantoms

Intracranial atherosclerotic disease (ICAD) is a leading cause of preventable ischemic stroke. Long-term management of chronic ICAD would benefit from directly quantifying key risk factors, such as the oxygen extraction fraction (OEF) and cerebrovascular reserve (CVR). The accurate measurement of the phase signal is vital to measuring OEF using MRI and seeing these effects through the cardiac cycle promises to elucidate CVR. A cardiac-gated, multi-shot, multi-echo rosette pulse sequence is developed and validated with simulation and a phantom study. The proposed pulse sequence and reconstruction pipeline produces strong off-resonance frequency measurements with a scan time under two minutes.

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Masahiro Takizawa¹, Takashi Nishihara¹, and Chikako Moriwake^1
1FUJIFILM Healthcare Corporation, 2-1, Shintoyofuta, Japan

Keywords: Pulse Sequence Design, Lung

Cylinder-shaped pre-saturation pulse train is modified to achieve non subtract scheme for non-contrast enhanced spatially-selective and time-resolved vessel imaging. The target vessel is selected by cylinder-shaped pre-saturation, and the dynamics of blood flow in the target vessel is observed by changing the number of applied pre-saturation pulses. The developed pulse train was demonstrated to visualize dynamics of a target pulmonary vessel in the lung.

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Tomokazu Tsurugizawa^1,2,3, Takuma Kumamoto⁴, and Yoshichika Yoshioka^3,5
1Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan, ²Faculty of Engineering, University of Tsukuba, Tsukuba, Japan, ³Center for Information and Neural Networks (CiNet), Osaka University and National Institute of Information and Communications Technology (NICT), Osaka, Japan, ⁴Developmental Neuroscience Project, Department of Brain & Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan, ⁵Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan

Keywords: Data Acquisition, Ex-Vivo Applications

The high-field MRI enables to investigate the microstructure in the mouse embryo. The proton-free fluid is used for the surrounding liquid around the specimen in MR-microimaging, but the potential issue of the image quality remains due to the air bubbles on the edge of the specimen and the motion artifact. Here, we demonstrated that the potato starch suspension with phosphate-buffered saline showed a low T1 and T2 signal intensity and strongly prevent the motion of the embryo during the scanning. These results indicate the utility of potato starch suspension for MR-microimaging of mouse embryos.

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Jason Andrew Reich¹, Erin MacMillan^2,3,4, and Rebecca Feldman^1,5
1Computer Science, Mathematics, Physics and Statistics, University of British Columbia, Kelowna, BC, Canada, ²UBC MRI Research Centre, Department of Radiology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada, ³SFU ImageTech Lab, Simon Fraser University, Surrey, BC, Canada, ⁴Philips Canada, Mississauga, ON, Canada, ⁵Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States

Keywords: Pulse Sequence Design, New Signal Preparation Schemes

Simultaneous multi-slice (SMS) pulse sequences have allowed for reductions in scan time with minimal signal-to-noise ratio loss. However, when ultrashort echo times (UTEs) are desired, SMS pulse sequences have been challenging to implement. In this work, we explore a UTE SMS pulse sequence that makes use of a power independent of number of slices prepulse to shape the transverse magnetization profile and a whole volume hard excitation to excite the remaining longitudinal magnetization. The novel pulse sequence is estimated to reduce scan times by a factor of approximately 7.6 when compared to UTE pulse sequences with three-dimensional acquisitions.

Xuelin Pan¹, Yuting Wen¹, Zhenlin Li¹, Xin Rong², and Miaoqi Zhang^3
1Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China, ²Department of Orthopedics, West China Hospital of Sichuan University, Chengdu, Sichuan, China, ³MR Research, GE Healthcare, Beijing, China

Keywords: Data Acquisition, Neuro

In this work, we propose a preoperative magnetic resonance examination of patients with lumbar disc herniation using the 3D MENSA sequence. This sequence was superior to cube, cube stir sequence in subjective and objective evaluation.The preoperative 3D MRI MENSA sequence is able to clearly depict the nerve roots and offer desirable contrast between the nerve roots, ligamentum flavum, bone, and intervertebral discs. Patients with lumbar degeneration can effectively benefit from the MENSA sequence since it provides informative imaging information to help understand disc herniation and compression of adjacent tissues when developing preoperative surgical strategies.

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Prasiddhi Neupane¹, Utsav Shrestha¹, and Aaryani Tipirneni-Sajja^1,2
1Biomedical Engineering, The University of Memphis, Memphis, TN, United States, ²St. Jude Children's Research Hospital, Memphis, TN, United States

Keywords: Data Analysis, Data Analysis

Multispectral fat-water-R2* models are used for the confounder-free assessment of hepatic iron overload. In this study, Monte Carlo-based virtual liver iron overload models were created, MRI signals were synthesized for GRE and UTE acquisitions, and the R2* values estimated using the monoexponential and the multispectral fat-water models were analyzed. Our results demonstrate that both multispectral models exhibit high accuracy and precision for UTE acquisition at both 1.5T and 3T.

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Austen Curcuru¹, Taeho Kim², Deshan Yang³, and H. Michael Gach^1,2,4
1Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO, United States, ²Radiation Oncology, Washington University School of Medicine, Saint Louis, MO, United States, ³Duke University, Durham, NC, United States, ⁴Radiology, Washington University School of Medicine, Saint Louis, MO, United States

Keywords: Artifacts, MR-Guided Interventions

Balanced steady state free procession (bSSFP) sequences are commonly used for real-time imaging during MRI guided radiotherapy treatments (MR-IGRT). bSSFP sequences offer high temporal resolution and SNR but are sensitive to B₀ fluctuations which lead to imaging artifacts during radiotherapy (RT) gantry rotatation.¹ Previous work demonstrated that RT gantry rotation induced artifacts could be significantly reduced by compensating for B₀ fluctuations using data from a free induction decay (FID) navigator prior to each bSSFP image.² A model-based approach to B₀ compensation using the gantry inclinometer was evaluated to reduce the SNR loss and temporal resolution associated with the navigator approach.  

Yingyi Hu^1,2, Yang Huang^2,3, Taiya Chen^1,2, Xinguo Lu⁴, Diangang Fang², Kan Deng⁵, and Zhiyong Li^2
1China Medical University, Shenyang, China, ²Department of Radiology, Shenzhen Children's Hospital, Shenzhen, China, ³Shantou University Medical College, Shantou, China, ⁴Internal Medicine-Neurology, Shenzhen Children's Hospital, Shenzhen, China, ⁵Philips Healthcare, Guangzhou, China

Keywords: Data Analysis, Quantitative Imaging, T2-mapping

To evaluate the potential of T2-mapping imaging as a qMRI marker for disease severity in Spinal muscular atrophy (SMA), we compared the T2 with muscle fat fraction (MFF), and clinical assessment of 13 muscles in the pelvis and thighs of 20 patients with SMA. A significant correlation was found between the mean T2 of all muscles and the patient’s clinical evaluation and MFF. Moreover, the highest mean T2 was found in the gluteus maximus, while the lowest in the adductor longus. Therefore, T2 mapping can be used as a quantitative and objective MRI technique to assess disease severity in SMA.