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Zahra Shams¹, Jiying Dai¹, Mark Gosselink¹, Wybe W.J.M. van der Kemp¹, Fredy Visser¹, Dennis W.J. Klomp¹, Hans J.M. Hoogduin¹, Tijl A. van der Velden¹, Giel Mens¹, Jannie P. Wijnen¹, and Evita C. Wiegers^1
1Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, Netherlands

Keywords: Data Acquisition, Data Acquisition

The purpose of this study is to assess the feasibility of an interleaved acquisition of ³¹P MRSI and ²³Na MRI. Triple-nuclei [metabolic] imaging of the brain was performed in one scan session with an interleaved acquisition of 3D ³¹P MRSI and 3D radial UTE ²³Na MRI at 7 Tesla. The results of the interleaved ²³Na-³¹P were compared with those acquired from non-interleaved runs, concluding no influence of each nucleus on the SNR or spectra quality. In conclusion, we showed that these two nuclei pools do not interfere with each other during interleaved acquisition. 

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Chencai Wang^1,2, Xiaodong Zhong³, Alfredo L. Lopez Kolkovsky⁴, Sonoko Oshima^1,2, Saneel Khairnar^2,5, and Benjamin M Ellingson^1,2,6,7
1Department of Radiological Sciences, UNIVERSITY OF CALIFORNIA, LOS ANGELES, Los Angeles, CA, United States, ²Brain Tumor Imaging Laboratory, University of California, Los Angeles, Los Angeles, CA, United States, ³MR R&D Collaborations, Siemens Medical Solutions USA, Los Angeles, CA, United States, ⁴Institute of Myology, Paris, France, ⁵Department of Molecular, Cell, and Developmental Biology, UNIVERSITY OF CALIFORNIA, LOS ANGELES, Los Angeles, CA, United States, ⁶Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States, ⁷Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States

Keywords: Pulse Sequence Design, Non-Proton, Sodium, 2-Nuclei

Extensive evidence suggests abnormal metabolism, sodium homeostasis, and tumor acidity are interconnected and play critical roles in brain tumor formation, progression, seizure activity, treatment resistance, and immune suppression. While Na⁺ and advanced H⁺ -based MRI techniques can provide this information, Na⁺ and H⁺ images are traditionally acquired sequentially, resulting in a total scan time exceeding what is clinically reasonable. In the current study, we demonstrate utility of a new interleaved sodium gradient echo and proton-based pH-sensitive amine chemical exchange saturation transfer echoplanar imaging (Na⁺-GRE/H⁺-CEST-EPI) sequence in 15 minutes, making it feasible to study patients with brain tumors.

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Riaz Hussain¹, Joseph W Plummer^1,2, Abdullah S Bdaiwi^1,2, Matthew M. Willmering¹, Laura L Walkup^1,2,3,4, and Zackary I Cleveland^1,2,3,4
1Center for Pulmonary Imaging Research, Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, ²Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, United States, ³Imaging Research Center, Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States, ⁴Department of Pediatrics, University of Cincinnati, Cincinnati, OH, United States

Keywords: Data Acquisition, Hyperpolarized MR (Gas)

Despite yielding high signal-to-noise ratio, conventional gradient recalled echo (GRE) sequence requires a relatively long breath-hold for ¹²⁹Xe ventilation imaging. 2D-spiral sequence enables faster imaging and offers possibility to correct regional B₁/flip-angle inhomogeneities and signal decay using keyhole reconstruction without making assumptions about bias texture that can obscure the physiology of interest. Here, GRE and 2D-spiral showed comparable image quality and revealed regional ventilation impairment in cystic fibrosis. Furthermore, flip-angle correction preserved signal variation due to underlying lung pathophysiology, including gravitation ventilation gradients and subtle defects. Thus, flip-angle corrections in 2D-spiral sequence may detect early and reversible disease-induced ventilation impairment.

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Hongchuang Li^1,2, Haidong Li^1,2, Ming Zhang^1,2, Xiaoling Liu^1,2, Xiuchao Zhao^1,2, Yeqing Han^1,2, Chaohui Ye^1,2, and Xin Zhou^1,2
1Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences- Wuhan National Laboratory for Optoelectronics, Wuhan, China, ²University of Chinese Academy of Sciences, Beijing, China

Keywords: Pulse Sequence Design, Hyperpolarized MR (Gas)

The mutual restriction of temporal and spatial resolution is a challenge for hyperpolarized gas dynamic MRI, especially for 3D acquisition. Herein, we proposed a methodology to image the pulmonary dynamic ventilation with high temporal and spatial resolution using hyperpolarized gas MRI based on a 3D gradient echo sequence. Furthermore, we observed the difference of pulmonary dynamic ventilation in the posterior-anterior direction. 

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Alexander Isaac Zavriyev¹, John Choi¹, Bukola Yetunde Adebesin¹, Molly M Sheehan¹, David J Tischfield¹, and Terence P. F. Gade^1
1University of Pennsylvania, Philadelphia, PA, United States

Keywords: Data Acquisition, Non-Array RF Coils, Antennas & Waveguides

Dynamic nuclear polarization magnetic resonance spectroscopic imaging (DNP-MRSI) of hyperpolarized carbon-13 (HP 13C) is an exciting new imaging technique that provides valuable information about the metabolism of disease states. Though there are many hyperpolarized substrates that can be used to investigate metabolism in a variety of models, the application of this technology often requires custom radiofrequency (RF) coil design. Furthermore, different coils within the same project may provide different results. In this study, we utilized 3D printing molds to generate inductors along with printed circuit board (PCB) designs to create a high reproducibility (<1% variation) pipeline for MR coils.

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Tanner M. Nickles^1,2, Yaewon Kim ¹, Philip M. Lee¹, Hsin-Yu Chen¹, Michael Ohliger¹, Peder E. Z. Larson^1,2, Zhen J Wang¹, Daniel B. Vigneron ^1,2, and Jermey W. Gordon^1
1Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²UC Berkeley-UCSF Bioengineering Program, University of California San Francisco, San Francisco, CA, United States

Keywords: Data Processing, Hyperpolarized MR (Non-Gas), Pancreas, Abdomen, Cancer

A substantial challenge in hyperpolarized (HP) ¹³C MRI is the limited signal-to-noise ratio (SNR) of downstream metabolites, which restricts the achievable spatial resolution. To overcome this for large coverage abdominal studies, a patch-based spatiotemporal denoising approach was applied to denoise dynamic imaging data in [1-13C]pyruvate echo-planar imaging (EPI) human datasets. With denoising, a 11.4 ± 1.8 and 8.7 ± 2.4 fold sensitivity gain was achieved for [1-13C]alanine and [1-13C]lactate, along with improved spatial coverage. These results support the potential of spatiotemporal denoising to improve quantification in HP ¹³C MRI for normal and cancer studies.

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Sung-Han Lin¹, Junjie Ma², and JaeMo Park^1,3
1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, ²GE Healthcare, New York, NY, United States, ³Radiology, UT Southwestern Medical Center, Dallas, TX, United States

Keywords: Data Processing, Cardiomyopathy

The volumetric patch-based super-resolution method can reconstruct a single-slice low-resolution hyperpolarized ¹³C MRI to multiple ¹³C slices with enhanced spatial resolution by exploiting the corresponding high-resolution structural ¹H MRI. In this study, the overall performance of this method and the effects of patch size were evaluated using a simulated digital phantom and an anthropomorphic cardiac ¹³C MR phantom. The optimal patch size for this reconstruction method was also applied to in-vivo human ¹³C cardiac images acquired with an injection of hyperpolarized [1-¹³C]pyruvate.

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Sang Hun Chung¹, Khoi Minh Huynh¹, Yong Chen², Pew-Thian Yap¹, Jennifer Goralski¹, Scott Donaldson¹, and Yueh Z Lee^1
1University of North Carolina Chapel Hill, chapel hill, NC, United States, ²Case Western Reserve University, Cleveland, OH, United States

Keywords: Data Acquisition, Lung, 19F fluorine

We studied the feasibility of multi breath wash-in/out lung acquisition with ¹⁹F gas and a sub 0.5 second acquisition spiral sequence. We compared the sub 0.5 seconds acquired data ability to measure wash-in/out time constants to a regular breath-hold ¹⁹F lung imaging and report correlation as well as differences in mean. Our results yielded high correlations (r > 0.88) for both wash-in and wash-out time constant calculations. The results indicate our proposed method yield similar calculated time wash-in/out time constants without the need for breath-holds and show promise for the use of free breathing ¹⁹F gas lung MRI.

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Xiaoxi Liu¹, Changhua Mu¹, Ying-Chieh Lai^1,2, Robert A. Bok¹, Romelyn Delos Santos¹, Yaewon Kim¹, Avantika Sinha¹, Jeremy Gordon¹, Robert Flavell¹, and Peder Larson^1
1Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, ²Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Taiwan, Taiwan

Keywords: Data Acquisition, Hyperpolarized MR (Non-Gas)

We present a dynamic pH measurement using metabolite-specific gradient-echo spiral sequence with flow suppression to improve the SNR of bicarbonate and CO₂ with short T₂^* and used bipolar gradients to suppress the high bicarbonate signal in the vessel. With the improved image quality and high temporal resolution, it is possible to measure the dynamic pH in vivo. Future studies will work to increase the sample size to confirm these results.

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Ching-Yi Hsieh^1,2, Ying-Chieh Lai³, Kuan-Ying Lu³, and Gigin Lin^1,2,3
1Institute for Radiological Research, Chang Gung University, Taoyuan, Taiwan, ²Clinical Metabolomics Core Laboratory, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, ³Department of Medical Imaging and Intervention, Chang Gung Hospital, Linkou, Taoyuan, Taiwan

Keywords: Data Processing, Hyperpolarized MR (Non-Gas), metabolites; apparent exchange rate; kinetic model

Downstream metabolites may have a poor SNR in hyperpolarized carbon-13 MRI, generating apparent exchange rate constant discrepancies when studying glycolytic flow in vivo or in vitro dynamically in real-time. We developed a method for estimating metabolite signal. This approach estimates metabolite signals using kinetic modeling and noise. The process was evaluated using simulations and in vitro studies. In vitro findings were also compared to 13C NMR cell media AUC. Comparing in vitro data from our method and NMR, both demonstrated consistency when uncertainty was included, suggesting that our method can accurately quantify metabolite signals and indicate how glycolytic flow changes.

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Qian Zhou^1,2, Haidong Li^1,2, Qiuchen Rao¹, Ming Zhang^1,2, Xiuchao Zhao^1,2, Luyang Shen¹, Yuan Fang¹, Hongchuang Li^1,2, Xiaoling Liu^1,2, Sa Xiao^1,2, Lei Shi^1,2, Yeqing Han^1,2, Chaohui Ye^1,2, and Xin Zhou^1,2
1Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences- Wuhan National Laboratory for Optoelectronics, Wuhan, China, ²University of Chinese Academy of Sciences, Beijing, China

Keywords: Data Acquisition, Hyperpolarized MR (Gas)

The long acquisition time of hyperpolarized ¹²⁹Xe multiple b-values DWI made it hard to apply in patients with severe pulmonary diseases. Herein, we proposed a method of variable-sampling-ratio compressed sensing patterns for accelerating hyperpolarized ¹²⁹Xe DWI. A four-fold reduction in acquisition time was achieved using the proposed method while preserving good image quality. Meanwhile, the method can be used for evaluating pulmonary injuries caused by cigarette smoking.

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Mostafa K Ismail¹, Steve Kadlecek¹, Hooman Hamedani¹, Faraz Amzajerdian¹, Ryan Baron¹, Luis Loza¹, Madeline Boyes¹, Klaus Hopster¹, Rachel Hilliard¹, Thomas Schaer¹, Benjamin Sinder², Patrick Cahill², Brian Snyder³, Kai Ruppert¹, and Rahim Rizi^1
1University of Pennsylvania, Philadelphia, PA, United States, ²Children’s Hospital of Philadelphia, Philadelphia, PA, United States, ³Boston Children’s Hospital, Boston, MA, United States

Keywords: Data Analysis, Hyperpolarized MR (Gas), Xenon

The ability to non-invasively measure air flow in the lungs could enable the early detection and assessment of abnormal air flow resulting from various obstructive and restrictive diseases. Here, we present a novel method for both obtaining and analyzing ventilation maps using hyperpolarized 129Xe MRI (HXe). In addition to assessing tidal volume and fractional ventilation, we introduce a novel sigmoid function describing inhalation and exhalation that enables the assessment of how fast air flows in the lungs and apply this method in a preclinical model of thoracic insufficiency syndrome (TIS) as well as three human lung transplant (LTx) recipients.

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Faiyza Shoaib Alam^1,2, Marcus John Couch³, Brandon Zanette², Daniel Li², Felix Ratjen^2,4, and Giles Santyr^1,2
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, ²Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada, ³Siemens Healthcare Limited, Montreal, QC, Canada, ⁴Division of Respiratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada

Keywords: Parallel Imaging, Hyperpolarized MR (Gas), multiple-breath washout, multiple-slice, fractional ventilation

Multiple-breath washout hyperpolarized ¹²⁹Xe MRI (MBW Xe-MRI) results in a regional map of fractional ventilation (FV), measuring percent gas clearance/breath. One limitation of previous work from our group is the single thick coronal slice (200mm) centered on the chest cavity results in significant partial volume effects. Acquiring multiple slices using parallel imaging adds spatial resolution in the slice direction. Feasibility of multiple-slice FV mapping using parallel acceleration is investigated in one adult. Median [IQR] FV was 0.35 [0.30 0.36]. Gravitational dependence was observed in posterior-anterior direction (-0.0122 cm^-1). Multiple-slice MBW Xe-MRI is feasible in healthy adults using parallel image acquisition.

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Tobias Speidel¹, Stephan Knecht², Klaus Kolb¹, Martin Gierse², and Volker Rasche^1
1Internal Medicine II, Ulm University Medical Center, Ulm, Germany, ²NVision Imaging Technologies GmbH, Ulm, Germany

Keywords: New Trajectories & Spatial Encoding Methods, Data Acquisition

Isotropic 3D imaging of hyperpolarized media is generally challenging due to the extremely limited lifetime of the hyperpolarized phase. Fortunately, images of hyperpolarized media are often intrinsically sparse, resulting in an excellent precondition for non-linear reconstruction techniques such as Compressed Sensing. To preserve this condition, a 3D Seiffert Spiral trajectory was implemented at 11.7 T, yielding low-coherent sampling properties for an arbitrary number of excitations, until depletion of the hyperpolarized signal. We show that qualitative images with a resolution of <500 $$$\mu$$$m can be reconstructed from continuous data that was acquired in less than one second.

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Junlan Lu¹, Elianna Bier², Suphachart Leewiwatwong², David Mummy³, Sakib Kabir³, Fawaz Alanezi⁴, Sudarshan Rajagopal⁴, Scott Haile Robertson⁵, Peter J Niedbalski⁶, and Bastiaan Driehuys^3
1Medical Physics, Duke University, Durham, NC, United States, ²Biomedical Engineering, Duke University, Durham, NC, United States, ³Radiology, Duke University, Durham, NC, United States, ⁴Cardiology, Duke University, Durham, NC, United States, ⁵Clinical Imaging Physics Group, Duke University, Durham, NC, United States, ⁶Pulmonary, Critical Care, and Sleep Medicine, University of Kansas Medical Center, Kansas City, KS, United States

Keywords: Data Analysis, Hyperpolarized MR (Gas), Keyhole reconstruction, Simulation

Cardiogenic red blood cell (RBC) signal oscillations in ¹²⁹Xe whole-lung dynamic spectroscopy provide a promising biomarker for identifying patients with pulmonary hypertension (PH). However, to detect more complex and heterogeneous diseases, it is necessary to move from simple global metrics to spatially resolved mapping. This has been demonstrated using keyhole reconstruction methods but little work has yet been done to optimize the reconstruction and visualization of these maps. Here, we introduce a digital phantom to investigate the effects of radial views, key radius, and SNR. From these simulations, we deduce a key radius of 9 points is optimal for minimizing radial undersampling-based heterogeneity and maximizing sensitivity.

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Marcel Awenius^1,2,3, Philipp Biegger¹, Christin Glowa⁴, Melanie Müller¹, Renate Bangert¹, Helen Abeln^1,3,5, Dominik Ludwig¹, Tristan A. Kuder¹, Mark E. Ladd^1,2,6, Peter Bachert^1,2, and Andreas Korzowski^1
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ²Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany, ³Max-Planck-Institute for Nuclear Physics, Heidelberg, Germany, ⁴Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ⁵Faculty of Chemistry and Earth Sciences, University of Heidelberg, Heidelberg, Germany, ⁶Faculty of Medicine, University of Heidelberg, Heidelberg, Germany

Keywords: Pulse Sequence Design, Hyperpolarized MR (Non-Gas), Carbon-13

In this study, a novel radially-sampled echo-planar spectroscopic imaging (rEPSI) sequence was implemented at a clinical 3T MR scanner to enable the non-invasive investigation of metabolic processes via hyperpolarized ¹³C substrates in real-time.

Customized data analysis pipelines yielded high quality spectra and volumetric intensity maps for in vivo experiments using hyperpolarized [1-¹³C]pyruvate. Data extracted from k-space center points enabled a non-localized quantification of T1 values.

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Robin A de Graaf¹, Yanning Liu¹, Zachary A Corbin¹, and Henk M De Feyter^1
1Yale University, New Haven, CT, United States

Keywords: Image Reconstruction, Deuterium

Deuterium Metabolic Imaging (DMI) is a novel method to generate spatial maps of dynamic metabolism. While DMI acquisition methods are simple and robust, DMI processing still requires expert user interaction, for example in the removal of extracranial natural abundance ²H lipid signals that interfere with metabolism-linked ²H-lactate formation. Here we pursue the use of MRI-based spatial prior knowledge to provide automated and objective lipid removal. Adequate lipid suppression without perturbation of brain voxels is achieved, thereby allowing the generation of distinct and reliable metabolic maps on patients with brain tumors.

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Hao Song¹, Hamidreza Saeidi¹, Johannes Fisher¹, Ali Caglar Özen¹, Stefan Schumann², and Michael Bock^1
1Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, ²Dept. of Anesthesiology and Critical Care, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany

Keywords: Data Analysis, Non-Proton

Information about T₂^* relaxation time plays an important role in data acquisition for ¹⁷O-MRI. In this work, we investigated the in vivo T₂^* relaxation time constants of ¹⁷O in regional brain tissue at 3T.  Overall, regional T₂^* relaxation times are in a range of 1.5 - 2ms (except for CSF). Additionally, a T₂^* variation of 0.12ms was found from superficial to deep layers in the insular cortex. Our results indicate that short-TE acquisition strategies are favorable for ¹⁷O-MRI of the brain.

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Yeong-Jae Jeon^1,2, Kyung Min Nam^3,4,5, Alex Bhogal³, and Hyeon-Man Baek^1,2
1Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon, Korea, Republic of, ²Lee Gil Ya Cancer & Diabetes Institute, Gachon University, Incheon, Korea, Republic of, ³Department of Radiology, University Medical Centre Utrecht, Utrecht, Netherlands, ⁴Institute for Diagnostic and Interventional Neuroradiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Bern, Swaziland, ⁵Translational Imaging Ceter, sitem-insel AG, Bern, Switzerland

Keywords: Data Processing, Spectroscopy, Non-Proton, Animals, Brain, Precision & Accuracy

We demonstrate the feasibility of a novel denoising approach utilizing a pretrained deep learning model with multiscale local polynomial smoothing for single voxel ³¹P MRS data in the mice brain at 9.4T. We evaluated the low-rank denoising, one of the popular methods and the proposed method using LCModel to compare their performance. Both methods resulted in improved signal-to-noise ratio and decreased uncertainty (Cramer-Rao Lower Bounds). In this work, the suggested method outperformed in signal-to-noise ratio enhancement.