Qingping Chen^1,2,3, Wieland A. Worthoff¹, and N. Jon Shah^1,2,4,5
1Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Germany, ²Department of Neurology, RWTH Aachen University, Aachen, Germany, ³Department of Biomedical Engineering, The University of Melbourne, Parkville, Australia, ⁴Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Germany, ⁵JARA - BRAIN - Translational Medicine, Aachen, Germany

It has been reported that enhanced SISTINA, one of the triple-quantum-filtered sodium MRI techniques, can selectively measure the distribution of restricted sodium, which may be sensitive to metabolic cellular dysfunction. In this work, the enhanced SISTINA sequence was optimized for 7T using FLORET, which has high k-space filling efficiency and good potential for undersampling. The optimized enhanced SISTINA sequence greatly improves the UTE image quality, while maintaining the multiple-quantum-filtered image performance and introducing incoherent randomness to the raw data. We believe the optimized enhanced SISTINA has promising potential for clinical applications with faster scans using compressed-sensing reconstruction in future.
 

Michiru Kajiwara¹, Tomoyuki Haishi^2,3, and Yasuhiko Terada^1
1Institute of Applied Physics, University of Tsukuba, Tsukuba, Japan, ²Department of Radiological Sciences, School of Health Sciences at Narita, International University of Health and Welfar, Narita, Japan, ³MRTechnology Inc., Tsukuba, Japan

²³Na MRI provides novel information on energy metabolism, and there are growing expectations for its application in clinical MRI. However, implementation of ²³Na MRI for existing ¹H MRI systems requires expensive dedicated transceivers and RF coils for sodium imaging. Here, we have developed an add-on crossband repeater system that can acquire ²³Na MRI signals simply by inserting it into the magnet’s bore of an existing ¹H MRI, and proved this concept by phantom and in vivo mouse experiments. This add-on platform is applicable to other ¹H MRI systems and will enhance the feasibility of ²³Na MRI in clinical practice.

Yibo Zhao^1,2, Rong Guo^1,2, Yudu Li^1,2, Keith R. Thulborn³, and Zhi-Pei Liang^1,2
1Department of Electrical and Computer Engineering, University of Illinois, Urbana-Champaign, Urbana, IL, United States, ²Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL, United States, ³Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, IL, United States

Quantitative sodium MRI is a unique tool for assessing tissue viability noninvasively. A major obstacle to widespread clinical applications of sodium MRI is low sensitivity, which leads to low spatial resolution even with long scan times. We present a novel method for reconstruction of high-resolution sodium maps from noisy, limited k-space data. The proposed method has been validated using simulated and experimental data, producing high-SNR and high-resolution tissue sodium concentration maps. These high-resolution maps were also shown to improve the detection of tumor responses to radiation therapy.

Fabian J. Kratzer¹, Sebastian Flassbeck^1,2,3, Sebastian Schmitter^1,4, Tobias Wilferth⁵, Arthur W. Magill¹, Benjamin R. Knowles¹, Tanja Platt¹, Peter Bachert¹, Mark E. Ladd¹, and Armin M. Nagel^1,5
1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ²Center for Advanded Imaging Innovation and Research, New York University, New York, NY, United States, ³Center for Biomedical Imaging, Dept. of Radiology, New York University, New York, NY, United States, ⁴Physikalisch Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany, ⁵Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen (FAU), Erlangen, Germany

Sodium relaxation times have been shown to be altered in several diseases. Hence, 2D sodium relaxometry using Magnetic Resonance Fingerprinting (²³Na-MRF) was demonstrated recently as a proof of concept. In this work an extension to a 3D sequence is presented. Furthermore, a more complex signal model based on irreducible spherical tensor operators was investigated. The feasibility of simultaneous 3D quantification of T₁, T_2s^*, T_2l^*, T₂^* and ΔB₀ was demonstrated in phantom measurements.

Hannes Michel Wiesner¹, Xiao-Hong Zhu¹, Maryam Sarkarat², Xin Li¹, Matt Waks¹, Michael T. Lanagan², Qing X. Yang³, and Wei Chen^1
1CMRR, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, ²Department of Engineering, Pennsylvania State College of Engineering, University Park, PA, United States, ³CNMRR, Department of Neurosurgery, Penn State University, Hershey, PA, United States

Recently we reported that the ceramics made of composite BST (Ba_0.6Sr_0.4TiO₃) material have an extremely high tunability of relative permittivity when changing the ceramic temperature; and by cooling the ceramics to 14-15 °C, they provided the best improvement for ¹⁷O MRSI application at 10.5T, resulting in an optimal permittivity of ~6000. In this study, we developed new ceramic disks made of mixed Ba_0.6Sr_0.4TiO₃ and BaTiO₃ (BST-BT) materials to achieve the optimal permittivity at room temperature. The results indicate that unprecedented performance is possible for ¹⁷O MRSI application at 10.5T without the need of a temperature controller.    

Ali Caglar Özen^1,2, Felix Spreter¹, Timo Heidt³, Constantin von zur Mühlen³, and Michael Bock^1
1Deptartment of Radiology, Medical Physics, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany, ²German Consortium for Translational Cancer Research Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany, ³Department of Cardiology and Angiology I, UHZ, University Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany

Fluorine magnetic resonance imaging is a non-invasive background-free MRI approach to image infiltrating monocytes. The transfer of ¹⁹F MRI into large animals is needed for both method validation and the development of clinical applications. In this study, we have developed an 8 transmit/ 8 receive coil array tuned to 115.9 MHz (at 3 T) and developed a detachable 19F coil system for cardiac and thoracic MRI in pigs.

Muhammed Yildirim^1,2, Patrick Scholtz², Markus Schütz², Xenia Kovalyk², Edwin Heijman^2,3, Rolf Lamerichs³, Holger Grüll², and Esin Ozturk Isik^1
1Computational Imaging Lab, Institute Of Biomedical Engineering, Bogazici University, Istanbul, Turkey, ²Institute of Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany, ³Philip Research Labs, Eindhoven, Netherlands

¹⁹F-MRI constitutes a viable platform for quantitative theranostics. However, being impaired by physiological absence, and complex NMR spectra of perfluorocarbons, for ¹⁹F-MR it is essential to achieve high imaging efficiency.  This work introduces a novel spectroscopic imaging sequence, BaSSI, that resides on a balanced psuedo-spiral acquisition scheme and compares against 3D balanced UTE SSFP imaging, that has become the golden standard of fluorine imaging.  The work, optimizes both sequences to their fullest, and tests their performance using miniscule samples of PFOB.

Simon Reichert¹, Dennis Kleimaier¹, and Lothar Schad^1
1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany

This study demonstrates the feasibility of low rank compressed sensing and non-uniform undersampled non-linear FID fitting for time efficient sodium TQTPPI measurements. In simulations, undersampling factors of up to 5 resulted in less than 10% deviation from the ground truth for all parameters. This accuracy was confirmed in measurement data of agarose and protein samples. Hence, a measurement time reduction up to a factor of 5 is possible without significantly reducing the accuracy of the fit parameters. Thus, CS allows for time efficient TQTPPI measurements to investigate cellular processes as well as isolated sodium protein interactions.

Jabrane Karkouri¹ and Christopher T. Rodgers^1
1Wolfson Brain Imaging Center, University of Cambridge, Cambridge, United Kingdom

In this abstract, we demonstrate a framework for interleaving 1H imaging and 31P spectroscopy on the Siemens 7T Terra platform. We show that this can be done without making hardware modifications and demonstrate the concept with interleaved B₀ map acquisition with 31P-MRS on a phantom and the quadriceps of a healthy volunteer.

Kwan-Jin Jung¹ and Brad Sutton^1,2
1Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ²Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States

Sodium MRI is challenging due to its low sensitivity and short T2 and hence a three-dimensional sequence with a spiral trajectory has been applied. The spiral trajectory was shortened in the TPI method by accelerating the span at the k-space origin using a radial start and then transiting into a spiral trajectory. This popular TPI method, however, requires a very high gradient slew rate when the 3D cone approaches the polar pole. This drawback has been resolved by rotating a two-dimensional disc filled with interleaved TPI trajectories. This method achieved the faster sweeping of TPI as well as a uniform gradient slew rate over the sphere sampling. We are reporting some artifacts in TPI-based scans not only in our study but also in other studies.

Alan J. Wright¹, Richard Mair^1,2,3, Anastasia Tsyben¹, and Kevin M. Brindle^1,3,4
1CRUK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, ²Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom, ³Cancer Research UK Major Centre-Cambridge, University of Cambridge, Cambridge, United Kingdom, ⁴Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom

Tensor decomposition can be used for denoising magnetic resonance spectroscopic imaging (MRSI) data by reconstructing the data from a small number of ranks. Selecting too low an order can remove data from the reconstruction and alter peak amplitudes. A condition for selection of rank order is proposed that removes only noise from the reconstructed data and, therefore, preserves signals from low amplitude resonances. Denoising algorithms that apply this condition are demonstrated for metabolic imaging data sets obtained with hyperpolarised [1-¹³C]pyruvate and [6,6-²H]glucose in preclinical cancer models, which improve signal-to-noise and reduce the Cramér-Rao lower bound errors in peak fitting.

Mark Armstrong¹, Felix Freppon², Enrica Wilken², Max Masthoff², Cornelius Faber², and Dan Xiao^1
1University of Windsor, Windsor, ON, Canada, ²Universität Münster, Münster, Germany

Individual iron oxide nanoparticle labelled immune cells can be visualized with a dynamic MRI image series. Time-lapse MRI can provide insights in the studies of inflammatory diseases and metastasis of cancer. The MRI temporal resolution can be improved by undersampling k-space. However, the optimal acceleration factor cannot be easily determined prior to experiments. Strategies have been proposed for non-Cartesian flexible retrospective undersampling, which may not be readily applicable for most users. We propose a Cartesian sampling scheme where undersampling ratio and temporal resolution can be chosen retrospectively. 

Parker John Bresnahan Jenkins¹, Guangle Zhang¹, Wei Zhu¹, Xiao-Hong Zhu¹, and Wei Chen^1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

To capture anatomical information and dynamic changes of different metabolic activities in the brain or other organs using a singular RF coil, we developed  a loop RF surface coil design with a wide tune-match isolation and active tune circuitry for proton ( ¹H) MRI, and interleaved deuterium ( ²H) and oxygen ( ¹⁷O) MRS measurements at 16.4T. We obtained static ¹H MRI and performed interleaved dynamic ²H and ¹⁷O measurements in phantom studies. Results showed proficient proton imaging and quasi-stable ²H and ¹⁷O signals with rapid acquisition, indicating the potential of the design for robust high temporal resolution metabolic and anatomical imaging applications.

Zhensen Chen¹, Yishi Wang², Le He¹, Hanyu Wei¹, Yibing Chen³, and Xiaolei Song^1
1Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, ²Philips Healthcare, Beijing, China, ³School of Information Science and Technology, Northwest University, Xi'an, China

Existing CEST methodologies suffer from low specificity in distinguishing various exchange species in tissue. To further utilize dependence of CEST spectra on saturation length (t_sat), power (B₁) as well as frequency, we setup a fast acquisition of Parametric VARied Saturation (PaVARS) in a 3T clinical scanner, by separating the seconds-long saturation preparation to 5-8 modules each followed by a low flip-angle readout. On phantoms of three metabolites and human brain, PaVARS enabled fast acquisition of multiple Zspectra, each weighted with different saturation length and power. PaVARS could be a ready-to-use, informative acquisition methods for better differentiation of endogeneous brain metabolites.

Nicholas Farley¹, Jaiyta Sood¹, Antonia Susjnar², Sean Lane³, Mark Chiew⁴, Michael Albert Thomas⁵, and Uzay Emir^1,2
1School of Health Sciences, Purdue University, West Lafayette, IN, United States, ²Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States, ³Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States, ⁴Welcome Center for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom, ⁵Department of Radiology, University of California Los Angeles, Los Angeles, CA, United States

To create a probabilistic Neurochemical atlas of the human brain via parcellated approach using ZOOM MRSI, in this study, we aim to quantify the test-retest reliability of the ZOOM MRSI by assessing the stability of the molecular contrasts of the posterior cingulate and cerebellum across two independent scan sessions and by quantifying the intra- and inter-rater reliability of the ZOOM MRSI scan.

Chengbin He¹, Xiaoxuan Zhou¹, Cailing Pu¹, Jingle Fei¹, Yan Wu¹, and Hongjie Hu^1
1Department of Radiology, Sir Run Run Shaw Hospital (SRRSH), Zhejiang University School of Medicine, Hangzhou, China

Gadolinium is a commonly used contrast agent for myocardial infarction during CMR examinations, but its nephrotoxicity and short examination time window limited its application to some extent. We try to develop new contrast agents with superior imaging performance and good biocompatibility, which can achieve clinical translation.

Christian T McHugh¹, Phillip G Durham², Michele Kelley¹, Paul A Dayton³, and Rosa T Branca^1
1Physics & Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ²Pharmacoengineering and Molecular Pharmaceutics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ³Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

Gas microbubbles are capable of providing both ultrasound and MRI image contrast, but at differing concentration levels. In order for gas microbubbles to be detected by MRI at the clinical ultrasound dose, a more sensitive detection scheme must be employed.  Here we demonstrate that hyperCEST is capable of detecting gas microbubbles at clinically relevant US concentrations, thus enabling their use as a dual modality contrast agent.

Chuyao Chen¹, Shaoshan Huang², Zelong Chen¹, Chenggong Yan¹, Yingjie Mei³, Yikai Xu¹, and Rui Guo^2
1Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China, ²Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Guangdong Provincial Engineering and Technological Research Centre for Drug Carrier Development, Department of Biomedical Engineering, Jinan University, Guangzhou, China, ³Philips Healthcare, Guangzhou, China

We have developed a KGN/SMNP loaded cell-therapy theranostic hydrogel scaffold for cartilage repair. The multifunctional hydrogel system is expected to be a tissue engineering strategy for cartilage regeneration and non-invasive monitoring by multiparametric MR imaging.

Shun Kishimoto¹, Jeffrey R Brender¹, Jeeva Munasinghe², Martin Lizak², Yu Saito¹, Kota Yamashita¹, Otowa Yasunori¹, Kazu Yamamoto¹, James Mitchell¹, and Murali C. Krishna^1
1NIH/NCI, Bethesda,, MD, United States, ²NIH/NINDS, Bethesda,, MD, United States

Aberrant glycogen metabolism has been implicated in vitro as a possible causative factor in multiple disorders. Progress has been stymied due to the rapid degradation of glycogen post mortem and the lack of methods for measuring glycogen metabolism in vivo. We show here that glucose metabolism and local synthesis of glycogen can be measured in mice by short echo PRESS following a single bolus of unlabeled glucose using a standard 3T preclinical MRI using low rank reconstruction. Imaging of glycogen synthesis was possible at 9.4T by CSI, where it was found in mice to be centered on the olfactory bulb  

Lin Lin^1,2, Xiaodan Chen³, and Pu-Yeh Wu^4
1Fujian Medical University Union Hosptial, Fuzhou, China, ²Fudan University Huashan Hospital, Shanghai, China, ³Fujian Cancer Hospital, Fuzhou, China, ⁴GE Healthcare, Beijing, China

Epilepsy is closely linked to inflammation, oxidative stress, and hypoxia. The difficulty of accurate localization and targeted drug delivery to the lesion hinders the effective treatment. The local activated inflammatory cells offer a new opportunity for drug delivery to the lesion. Here, CD163 positive macrophages were first utilized as cell carriers after being hijacked by targeted albumin nanoparticles, which effectively delivered nanoparticles to the epileptic sites. Thus, accumulative nanoparticles enabled the visualization of the epileptogenic lesion though microenvironment-responsive MR-T1W imaging. Moreover, these manganese-based nanomaterials played a crucial role in protecting neurons from cell apoptosis mediated by oxidative stress and hypoxia.