Xiang Xu¹, Ding Xia¹, Kai Tobias Block², and Li Feng^1
1Department of Radiology and BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²Center for Advanced Imaging Innovation and Research (CAI2R) and Department of Radiology, New York University School of Medicine, New York, NY, United States

In this project, we proposed a fast 3D CEST MRI technique called GraspCEST, which is based on the combination of CEST-prepared stack-of-stars golden-angle radial sequence and multicoil compressed sensing reconstruction. Using this technique, we were able to perform lipid suppressed, free-breathing 3D CEST imaging of the liver. We have demonstrated that it is possible to accelerate imaging speed and achieve full Z-spectra acquisition of the liver within 5 min. The GraspCEST technique can be a useful tool in studying glycoNOE in the liver. 

Solène Bardin^1,2, Fawzi Boumezbeur^1,2, and Luisa Ciobanu^1,2
1NeuroSpin, CEA, Gif-sur-Yvette, France, ²Paris-Saclay University, Gif-sur-Yvette, France

Accelerated acquisitions with a CEST-linescan sequence coupled with the estimation of the local baseline for the analysis of the Z-spectra allow to simultaneously monitor dynamic changes at several CEST contributions induced by a controlled pH decrease. This approach can be a promising strategy for detecting functional induced metabolic changes devoid of confounding BOLD effects.

Lucia Nichelli^1,2, Julian Jacob³, Delphine Leclerq¹, Farhat Benbelkacem⁴, Stéphane Lehéricy^1,2, and Stefano Casagranda^5
1Department of Neuroradiology, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière-Charles-Foix, Sorbonne Université, Paris, Paris, France, ²Paris Brain Institute – Institute du Cerveau (ICM), Centre de NeuroImagerie de Recherche (CENIR), F-75013, Paris, France, ³Department of Radiation-Oncology, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière-Charles-Foix, Sorbonne Université, Paris, France, ⁴Siemens Healthcare SAS, Saint-Denis, Paris, France, ⁵Department of Research & Innovation, Olea Medical, La Ciotat, France

Distinguishing tumor recurrence from radionecrotic injury of pre-irradiated brain metastases is fundamental to provide optimal patient care. Unfortunately, this distinction is often hard to make even with advanced MRI multimodal protocols. This study aims to evaluate APTw imaging in predicting the differentiation between radio-induced tissue changes from tumor progression at 3T in 20 pre-irradiated metastases. Results show that APTw metrics can significantly separate these two common radiological entities (p<0.0001) and suggest the use of fluid-suppressed APTw to reach higher discriminating values.

Munendra Singh¹, Babak Moghadas¹, Shanshan Jiang¹, Peter van Zijl¹, Jinyuan Zhou¹, and Hye-Young Heo^1
1Johns Hopkins University, Baltimore, MD, United States

High-resolution MRF including a multi-pool saturation transfer model requires a huge dictionary or training dataset simulated with Bloch equations. Furthermore, intensive Bloch simulation tasks are inevitable for MRF schedule optimization. In this study, we developed a deep-learning-based ultrafast Bloch simulator and a recurrent neural network (RNN) for semi-solid macromolecular magnetization transfer contrast (MTC) MRF reconstruction. For the MRF training dataset generation, the deep-learning Bloch simulator required ~200x less time than a conventional Bloch simulation. A test-retest study showed excellent reliability of the tissue parameter quantification using the proposed RNN framework. 

Ayhan Gursan¹, Arjan D. Hendriks¹, Dimitri Welting¹, Dennis W.J. Klomp¹, and Jeanine J. Prompers^1
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands

Kidneys play a crucial role in glucose homeostasis via glucose reabsorption and glucose release into and glucose uptake from the circulation. We investigated the feasibility of measuring renal glucose uptake and metabolism with dynamic 3D DMI. A volunteer was scanned twice with two different ways of deuterated glucose administration: in the scanner and before scanning session. Similar glucose uptake was observed in the kidney and liver. We demonstrated the feasibility of measuring renal glucose uptake and metabolism with dynamic 3D DMI. This technique has potential to study the role of renal glucose uptake in glucose homeostasis in diabetes.

Anina Seidemo¹, Ronnie Wirestam¹, Gunther Helms¹, Karin Markenroth Bloch², Xiang Xu^3,4, Johan Bengzon^5,6, Pia C. Sundgren^2,7,8, Peter C.M. van Zijl^3,9, and Linda Knutsson^1,3,9
1Department of Medical Radiation Physics, Lund University, Lund, Sweden, ²Lund University Bioimaging Center, Lund University, Lund, Sweden, ³Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, ⁴BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ⁵Lund Stem Cell Center, Department of Clinical Sciences, Lund University, Lund, Sweden, ⁶Division of Neurosurgery, Department of Clinical Sciences, Lund University and Skåne University Hospital, Lund, Sweden, ⁷Department of Medical Imaging and Physiology, Skåne University Hospital, Lund and Malmö, Sweden, ⁸Diagnostic Radiology, Department of Clinical Sciences, Lund University, Lund, Sweden, ⁹F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States

Dynamic glucose-enhanced (DGE) MRI provides time intensity curves after D-glucose injection and is promising as a less invasive alternative or complement to dynamic contrast-enhanced (DCE) MRI. Here, we calculated non-model-based parameter maps from DGE and DCE MRI of human brain tumors, and created color-coded “curve maps”, a graphic representation of different curve shapes, to further investigate temporospatial enhancement patterns. The results show that DGE MRI can differentiate tumor from healthy brain tissue, that DGE and DCE give similar but not identical information, and that the proposed curve map approach has potential to aid in visual assessment of dynamic images.

Loreen Ruhm^1,2,3, Theresia Ziegs^1,2, Andrew Wright^1,2, Nikolai Avdievich¹, and Anke Henning^1,3
1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany, ²IMPRS for Cognitive and Systems Neuroscience, Eberhard-Karls University of Tuebingen, Tuebingen, Germany, ³Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States

The tracing of glucose metabolism is of interest in many pathologies of the human brain. In this abstract, we compare the information content of ²H MRSI detected deuterium metabolic imaging (DMI) to quantitative exchanged-labeled turnover ¹H MRS (QELT), both measured at B₀ = 9.4 Tesla. An uptake of ²H labeling was detectable for different metabolites for both methods. Consistent changes in ²H labeled Glx after the oral administration of [6,6’-²H₂]-glucose were detected in the brain of healthy human subjects. 

Teresa Gerhalter¹, Anna M Chen¹, Seena Dehkharghani^1,2, Rosemary Peralta¹, James S. Babb¹, Tamara Bushnik³, Alejandro Zarate³, Jonathan M Silver⁴, Brian S Im³, Stephen P Wall⁵, Ryan Brown^1,6, Ivan I Kirov^1,2,6, and Guillaume Madelin^1
1Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States, ²Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States, ³Department of Rehabilitation Medicine, New York University Grossman School of Medicine, New York, NY, United States, ⁴Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, United States, ⁵Ronald O. Perelman Department of Emergency Medicine, New York University Grossman School of Medicine, New York, NY, United States, ⁶Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States

In this longitudinal sodium MRI study, mild traumatic brain injury (mTBI) patients and controls were scanned at 3T. Linear regression analysis was used to calculate total sodium concentrations (TSC) in global grey and white matter (GM, WM). Patient GM TSC increased back to control levels at 3-month and 1-year follow-ups. Decreased GM and WM TSC measured at one month were associated with worse cognitive performance, but not worse symptomalogy, at the follow-up visits.

Gonzalo G Rodriguez¹, Zidan Yu^1,2, Lauren O'Donnell¹, Liz Calderon¹, Sarah Shaykevich², Martijn A Cloos^3,4, and Guillaume Madelin^1,2
1Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²Vilcek Institute of Graduate Biomedical Sciences, NYU Langone Health, New York, NY, United States, ³Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia, ⁴ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, Brisbane, Australia

In this work, we present an algorithm to generate a high-resolution ²³Na image from simultaneously-acquired low-resolution ²³Na density-weighted MRI (2.85×2.85×5 mm³) and high-resolution ¹H density, T₁, and T₂ maps from MRF (1.5×1.5×5 mm³) in brain at 7 T. As a result, the mean value of the difference between the generated and ground truth high-resolution ²³Na images is 0.5% with a standard deviation of 6.2% and multi-scale structural similarity index of 0.97.

Ludger Starke^1,2, Paula Ramos Delgado¹, Jason M. Millward¹, Sabrina Klix¹, Thoralf Niendorf^1,3, and Sonia Waiczies^1
1Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, ²Digital Health Center, Hasso Plattner Institute, Potsdam, Germany, ³Experimental and Clinical Research Center (ECRC), A Joint Cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany

Improving sensitivity has been the major challenge towards realizing the promises of ¹⁹F-MRI. Here we combine a cryogenic surface RF probe and compressed sensing to achieve high spatially resolved ¹⁹F-MRI of neuroinflammation in a challenging longitudinal study. Inflammation in the CNS was observed even in the absence of neurological symptoms and detailed signals along the CNS vasculature are clearly resolved. Together with effective longitudinal registration this allows an in-depth study of disease progression.