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| 4973.
 | Noninvasive quantification of ketamine-induced structural plasticity in mice using multishell diffusion weighted imaging Sedona Noel Ewbank1, Alex Ronald Hart1, Austen Brooks Casey2, Jennifer A McNab1, Boris Dov Heifets2, and Raag Dar Airan1
1Department of Radiology, Stanford University, Stanford, CA, United States, 2Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA, United States Keywords: Pharmacology, Diffusion/other diffusion imaging techniques, Pharmacology Motivation: To monitor treatment, we need noninvasive quantitation of the microstructural changes known to accompany rapid-acting antidepressant therapy. Goal(s): Our goal was to develop a noninvasive biomarker of the structural plasticity induced by rapid-acting antidepressants. Approach: Neurite orientation dispersion and density imaging (NODDI) was assessed before and after treating male and female mice with ketamine, with or without opioid blockade. Results: Ketamine induced alterations of orientation dispersion index (ODI) and neurite density index (NDI) in brain regions involved in mood regulation and reward processing, particularly in females. Curiously, opioid blockade induced trendwise increases in NDI and ODI across multiple brain regions, independent of ketamine.
Impact: Our preliminary results indicate that multishell diffusion MRI tracks the brain microstructural changes known to be induced by ketamine and related rapid-acting antidepressants, enabling a noninvasive quantitative biomarker that could be used to track individual patient response to antidepressant therapy. |
| 4974.
 | Accelerated Cortical Thickness Mapping Using Deep Learning Jia-Xiu Chen1, Teng-Yi Huang1, Yu-Chen Liao1, and Jui-Jung Yu1
1National Taiwan University of Science and Technology, Taipei, Taiwan Keywords: Gray Matter, Data Analysis, Deep learning,Cortical thickness,ADNI Motivation: The long processing time of current CT mapping methods hampers their use in clinical research. A faster and reliable CT mapping alternative is needed. Goal(s): To create a deep-learning model that reduces CT mapping time without compromising accuracy or the ability to classify Alzheimer's disease. Approach: We trained a 3D U-Net-based model on T1-weighted MRI datasets to produce CT maps, generating two model variants—one using skull-stripped and the other using both whole-brain and skull-stripped images. Performance was benchmarked against FreeSurfer. Results: The complete Unet-based CT mapping workflow, inclusive of preprocessing, was executed in under a minute without relying on GPU acceleration. Impact: The developed deep-learning-based
method, executed within a minute, could accelerate neurological research related
to CT values by providing fast and reliable procedure for CT mapping. |
| 4975.
 | Time course of structural neuroplasticity induced by procedural motor learning: DTI vs SANDI Guillermina Griffa1, Marco Palombo2, Abraham Yeffal1, Hong-Hsi Lee3, Susie Y. Huang3, and Valeria Della-Maggiore1
1IFIBIO-Houssay, Department of Physiology, School of Medicine, University of Buenos Aires, Argentina, Buenos Aires, Argentina, 2Brain Research Imaging Centre (CUBRIC), School of Psychology and School of Computer Science and Informatics, Cardiff University, Cardiff, UK., Cardiff, United Kingdom, 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA., Boston, MA, United States Keywords: Gray Matter, Neuroscience, motor learning, plasticity, SANDI Motivation: Performance gains during motor sequence learning (MSL) are linked to increased hippocampal activity and fast changes in mean diffusivity. Yet, DTI is not biologically specific. Goal(s): To identify the biological compartment(s) driving changes in gray-matter microstructure during MSL. Approach: We applied SANDI to multi-shell-DWI acquired in 28 subjects on the Connectome scanner before, 30 min, and 24h post MSL training. Results: MSL-induced transient changes in DTI were associated with a temporary increase in soma fraction at 30 min, compatible with a fast homeostatic response (e.g. astrocytic swelling). Long-lasting DTI changes were associated with an increment in neurite fraction compatible with structural remodelling. Impact: Our work may broaden the scope of understanding of human hippocampal memory and help pinpoint the biological substrates of plasticity. Moreover, it may set the basis for developing a biologically meaningful biomarker of neuroplasticity to detect early signs of neuropathology. |
| 4976.
 | The causal effect of insomnia on the hippocampal volume and hippocampal plasticity Xixi Dang1 and Yinghe Chen2
1Department of Psychology, Hangzhou Normal University, Hangzhou, China, 2Faculty of Psychology, Beijing Normal University, Beijing, China Keywords: Gray Matter, Brain, Mendelian randomization; sleep;hippocampus Motivation: The causal relationship between the sleep-related traits and the plasticity of subcortical brain volumes remains unclear. Goal(s): This study aims to explore the causal relationship between two sleep-related traits (i.e., sleep duration and insomnia) and subcortical volumes. Approach: Two-sample Mendelian randomization (MR) analysis Results: We found a significant causal effect of insomnia but not sleep duration on the hippocampal volume. Moreover, insomnia showed significant causal influence on the structural plasticity of the hippocampus, which may associated with the rates of hippocampal atrophy. Impact: The causal effect of insomnia on the hippocampal volume and plasticity may explain the adverse effect
of insomnia on memory and may offer new evidence which could push the exploration of sleep management to delay the course of neurodegenerative diseases. |
| 4977.
 | Hybrid dynamic bright and black blood angiography by vessel-selective saturation angiography Wiebke Entelmann1, Monika Huhndorf2, Olav Jansen2, and Thomas Lindner1
1Neuroradiology, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany, 2Radiology, UKSH Kiel, Kiel, Germany Keywords: Blood Vessels, Vessels Motivation: Examining a simultaneous bright and black blood sequence. Goal(s): Demonstrate ability to simultaneously acquire bright and black blood contrast in one image, providing simultaneous information on time-resolved artery-selective blood flow as well as the vessel walls integrity. Approach: Feasibility was evaluated by comparing calculated magnetization from a Bloch simulation and measured signal values from volunteer. Results: Simulated and measured image data showed a largely similar course over time points. An outlier time point has to be further investigated. Best black blood contrast to surrounding tissue was not found at the time point with the lowest blood signal. Impact: The study demonstrates the ability to
simultaneously acquire bright and black blood contrast in a single image set
and resulting simultaneous information on time-resolved artery-selective blood
flow as well as the vessel walls integrity. |
| 4978.
 | Fontan Patients Exhibit Altered CBF and ATT Measurements in Gray and White Matter: an ASL Study. Emma Carpenter1, Clio González-Zacarías1,2, Sneha Verma1, Jian Shen1,3, Botian Xu1,3, Soyoung Choi4, Silvie Suriany1, Koen Baas5, Anand Joshi2, Richard Leahy2, Peter Chiarelli6, and John Wood1,7
1Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, United States, 2Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California Viterbi School of Engineering, Los Angeles, CA, United States, 3Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States, 4Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 5Department of Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, 6Pediatric Neurosurgery, Children's Hospital Los Angeles, Los Angeles, CA, United States, 7Pediatrics CHLA, Keck School of Medicine of USC, Los Angeles, CA, United States Keywords: Blood Vessels, Arterial spin labelling, Fontan, CBF, ATT, Oxygen Delivery Motivation: Patients with Fontan palliation of single ventricular heart disease have significant cognitive deficits that may result from their chronically low cardiac output. Goal(s): To determine whether global and regional brain oxygen delivery is normal in young adults after Fontan palliation. Approach: We measured cerebral blood flow (CBF) and arterial transit time (ATT) in 28 young adult Fontan patients and 31 age and sex matched control subjects using pseudocontinuous time-encoded arterial spin labeling (PCASL). Results: CBF and arterial transit time were increased, in Fontan subjects compared with controls. Oxygen delivery was decreased in the anterior and middle cerebral artery distribution. Impact: These data suggest that physiologic compensation to the low cardiac output state produced by Fontan circulation is insufficient to maintain cerebral oxygen delivery. Time-encoded PCASL potential provides an important biomarker to judge surgical and medical interventions in these patients. |
| 4979.
 | Longitudinal Imaging of Spinal Cord Myelin Following C5 Hemisection Lesions with 3D Ultrashort Echo Time (UTE) Magnetization Transfer MR Imaging Qingbo Tang1,2, Yajun Ma1, Qun Cheng3, Jiang Du1, Paul Lu3, and Eric Y Chang1,4
1Radiology, UCSD Health, La Jolla, CA, United States, 2Research Service, Veterans Affairs San Diego Healthcare System, San Diego, CA, United States, 3Neuroscience, UCSD Health, La Jolla, CA, United States, 4Radiology Service, Veterans Affairs San Diego Healthcare System, San Diego, La Jolla, CA, United States Keywords: Spinal Cord, White Matter Motivation: To characterize the dynamic spinal myelin changes in rats following C5 hemisection lesions, and to monitor the efficacy of stem cells or other remyelination treatments Goal(s): To detect myelin degeneration or regeneration in the spinal cord after SCI Approach: The rats were imaged post-injury noninvasively and longitudinally with a UTE-MT sequence for MT ratio (MTR) measurement1. White matter was approximated by thresholding the MTR maps using values from the intact left (contralateral) side of spinal cord. Results: A decrease in the white matter was observed on the right (ipsilateral) side caudal to the lesions, consistent with known myelin changes following spinal cord injury Impact: Myelin changes in the rat spinal cord following hemisection
lesions can be monitored non-invasively and longitudinally with MT ratio measurement. Such techniques can
be used to detect myelin degeneration or regeneration in the spinal cord after
SCI. |
| 4980.
 | Detection of intracranial hemorrhage in healthy neonatal mice by T2*-weighted 7T MRI Rena Kono1, Maiko Ono2, Raj Kumar Parajuli2,3, Ryuta Koyama1, and Yuhei Takado2
1Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan, 2Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Chiba, Japan, 3Sydney Imaging Core Research Facility, The University of Sydney, Sydney, Australia Keywords: Blood Vessels, Normal development, high-field MRI Motivation: Neonatal brain hemorrhage, which are observed in premature and even in full-term infants, could cause adverse neurological damage, however, the mechanism of hemorrhages is unknown and the validated information for neonatal hemorrhages, especially in asymptomatic neonates, is lacking. Goal(s): Our goal was to detect hemorrhages in the brains of untreated postnatal mice and evaluate the spatiotemporal information. Approach: T2*-weighted MR images were obtained from records of C57BL/6J mice at P0-1 and acquired hemorrhages were cross-validated by histological analysis. Results: We found that hemorrhages occur throughout the brain of healthy neonatal mice. Impact: In vivo MRI of untreated postnatal mice may serve as a useful tool to further investigate asymptomatic hemorrhages in full-term infants and will deepen our understanding of not only the mechanism of neonatal hemorrhages but also the brain development. |
| 4981.
 | Combining Inhomogeneous Magnetization Transfer and Myelin Water Imaging at 9.4T: Methodology and Limitations Masha Novoselova1,2,3, Andrew Yung2,3, and Piotr Kozlowski1,2,3
1Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada, 2Radiology, University of British Columbia, Vancouver, BC, Canada, 3UBC MRI Research, Vancouver, BC, Canada Keywords: White Matter, Spinal Cord Motivation: Myelin imaging techniques are often qualitative and lack specificity, hindering precise understanding of white matter and neurodegenerative diseases. Goal(s): This study aimed to enhance myelin imaging by combining Inhomogeneous Magnetization Transfer (ihMT) and Myelin Water Imaging (MWI) at 9.4T. Approach: Incorporating ihMT saturation pulses with the multi-echo spin-echo MWI readout acquisition facilitates myelin quantification through multi-contrast mechanisms. ihMT images protons with extended dipolar relaxation times, while MWI extracts myelin water contributions from T2 distributions. Results: Results revealed irregularities due to high-field-induced shortening of myelin water T2 values. Therefore, full T2 distributions could not be resolved, impeding further analyses such as myelin quantification.
Impact: This study presents a myelin-specific imaging approach through the fusion of two quantitative techniques at 9.4T. Unresolved myelin water T2 peaks caused by the high field strength present a challenge, underscoring the need for further exploration at lower field strengths. |
| 4982.
 | Amide Proton Transfer Magnetic Resonance Imaging of Type 2 Diabetes Mellitus: A Preliminary Study Hongjun Jiang1, Shuncheng Yu1, Langxuan Yu1, Peng Sun2, Liangjie Lin2, and Weiwei Wang1
1Radiology department, The first affiliated hospital of Dalian medical university, Dalian City, China, 2Clinical & Technical Support, Philips Healthcare (Beijing), China, Beijing, China Keywords: Other Neurodegeneration, Diabetes, APT T2DM Motivation: APT imaging has been used to study neurodegenerative diseases,T2DM is also known to be associated with cognitive decline and brain structural changes,so, it is interesting to explore the cerebral metabolic alternation of T2DM. Goal(s): This study investigated the feasibility of APT to monitor the condition of T2DM patients. Approach: Twenty T2DM patients and Twenty age- and sex-matched healthy controls (HCs) underwent conventional MR and APT scanning,The image analysis of APT was performed by 3D Slicer software. Results: The results showed that the APT values in the left temporal white matter of T2DM patients were lower and significantly different from healthy controls. Impact: By APT technique,
temporal lobe white matter APT signal values were found to be lower in T2DM
patients than in healthy controls, which can provide more information on
cerebral metabolic changes in T2DM patients. |
| 4983.
 | Characterisation of brain T2* Values across the neonatal period at 7 Telsa Elisabeth Sarah Pickles1,2, Jucha Willers Moore3,4, Philippa Bridgen1,2, Alena Uus3, Jo V Hajnal2,3, Maria Deprez3, Anthony Price1,3, Tomoki Arichi1,3,4, and Shaihan Malik2,3
1Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom, 2London Collaborative Ultra high field System (LoCUS), London, United Kingdom, 3Centre for the Developing Brain, King's College London, London, United Kingdom, 4Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom Keywords: Neonatal, Brain, High-field MRI, Neuro, Relaxometry Motivation: Brain T2* values can provide information about tissue specific maturation, and can also provide knowledge important for optimising echo times for fMRI acquisition. Goal(s): To characterise tissue specific T2* values in the neonatal brain at 7T. Approach: Whole brain T2* maps from 14 neonates were generated using a 3D multi-echo acquisition. Results: Median T2* values were: cortical grey matter: 58 ms, deep grey matter: 70 ms and white matter: 86 ms. Values differ markedly from those described in adults and measured at standard field strengths. Impact: We describe tissue-specific T2* values in the neonatal brain at 7T, which may provide new information about brain development in health and disease, and provide a basis for optimising fMRI sequences for neonates at 7T. |