ISSN# 1545-4428 | Published date: 19 April, 2024
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At-A-Glance Session Detail
   
Imaging Brain Anatomy & Physiology
Oral
Preclinical
Thursday, 09 May 2024
Hall 606
08:15 -  10:15
Moderators: Emmanuel Barbier & Cristina Cudalbu
Session Number: O-67
CME Credit

08:15 Introduction
Emmanuel Barbier
08:271125.
Towards a multi-parametric MRI-based myelin marker in the developing mouse brain
Choong Heon Lee1, Jennifer A Minteer2, Zifei Liang1, Yongsoo Kim2, and Jiangyang Zhang1
1Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States, 2Department of Neural and Behavioral Sciences, Penn State University, Hershey, PA, United States

Keywords: Biomarkers, Neuro

Motivation: Although several myelin markers have been introduced using MRI, their ability to accurately detect myelin has been limited in sensitivity and specificity.

Goal(s): MP-MRI shows promise in improving myelin mapping, but validating its effectiveness remains a challenge. Our aim is to create a MP-MRI indicator and verify its accuracy through 3D myelin histology.

Approach: We compared myelin histology in MOBP-eGFP mouse brains, which exhibit enhanced myelination with various MRI markers in the same subjects.

Results: We observed varying degrees of correlation between MRI markers and MOBP signals in different brain regions. Employing PLSR analysis revealed that MP-MRI has potential to enhance myelin mapping.

Impact: The integration of multiple MRI markers in multiparametric MRI has the potential to improve our capacity for mapping myelin in the brain. A direct biomarker of myelin would be highly impactful for management of patients with MS and de/dysmyelinating disorders.

08:391126.
Mapping glymphatic solute transportation through the perivascular space of hippocampal arterioles with 14 Tesla MRI
Xiaoqing Alice Zhou1,2, Weitao Man1,2, Xiaochen Liu1,2, Yuanyuan Jiang1,2, David Hike1,2, Lidia Gomez Cid1,2, Sangcheon Choi1,2, Changrun Lin1,2, and Xin Yu1,2
1A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, 2Harvard Medical School, Boston, MA, United States

Keywords: Small Animals, Vessels, Glymphatic

Motivation: The perivascular space (PVS) plays a crucial role in facilitating the clearance of waste products and the exchange of cerebrospinal fluid and interstitial fluid in the central nervous system.

Goal(s): However, the limited depth penetration of current imaging methods impedes the study of glymphatic dynamics in deep brain regions.

Approach: In this study, we introduced an ultra-high-resolution dynamic contrast-enhanced MRI mapping approach based on single-vessel multi-gradient-echo methods.

Results: This technique allowed the differentiation of penetrating arterioles and venules from adjacent parenchymal tissue voxels and enabled the detection of Gd-enhanced signals coupled to PVS of penetrating arterioles in the deep cortex and hippocampus.

Impact: The study revealed significant PVS-specific Gd signal enhancements, shedding light on glymphatic function in deep brain regions. These findings advance our understanding of brain-wide glymphatic dynamics and impaired waste clearance, warranting further exploration of their clinical relevance and therapeutic applications.

08:511127.
High resolution pCASL mapping of perfusion in the mouse brain
Sara Pires Monteiro1,2, Lydiane Hirschler3, Emmanuel L. Barbier4, Patrícia Figueiredo2, and Noam Shemesh1
1Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal, 2Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal, 3C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 4Université Grenoble Alpes, Inserm, Grenoble Institut des Neurosciences, Grenoble, France

Keywords: Biology, Models, Methods, Perfusion, Arterial Spin Labelling

Motivation: pCASL perfusion mapping has many potential applications in preclinical imaging, but its use is still challenging particularly in mice and at higher fields due to limited sensitivity and constraints on labelling arising from the mouse’s anatomy. 

Goal(s): Here, we set to push the spatial resolution limitations of pCASL in mice by over an order of magnitude.

Approach: For this, we leverage SNR increases provided by cryogenic coils and develop a novel experimental setup optimizing and stabilizing the positioning of the mice.

Results: We then show x11 higher spatial resolution CBF maps compared to the previous state-of-the-art and higher stability and reproducibility of findings. 

Impact: We developed a setup optimizing carotid positioning for mice, thereby enabling efficient pCASL labeling. When combined with a cryogenic coil, perfusion images of the mouse brain were enhanced x11 in spatial resolution and were highly reproducible compared to current state-of-the-art. 

09:031128.
The resolution dependence of MRI vessel size index varies across brain regions.
Dongkyu Lee1, Yelim Gong1, Sohyun Han2, and HyungJoon Cho1
1Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea, Republic of, 2Korea Basic Science Institute, Cheongju, Korea, Republic of

Keywords: Perfusion, Vessels, vessel size index, VSI, resolution dependence

Motivation: Vessel size index (VSI) MRI of the rodent brain is measured at various in-plane resolutions, but the resolution dependence of VSI has not yet been explored.

Goal(s): Here, we investigated the differences in rat brain VSI at mostly measured in-plane resolutions of 125μm2 and 250μm2.

Approach: Resolution-dependent differences in VSI across brain regions were investigated in in-vivo rat experiments via a steady-state susceptibility contrast method by injection of monocrystalline iron oxide nanoparticles and validated through Monte Carlo simulations.

Results: In the white matter and hippocampus regions, the VSI was measured to be 12% larger as the resolution was lowered from 125μm2 to 250μm2.

Impact: Because the resolution dependence of VSI quantification varies across brain regions depending on the vascular configuration within MRI voxels, caution is required when comparing and analyzing brain VSI MRI obtained at different resolutions.

09:151129.
Charting vascular network architecture in primate brain using ferumoxytol-weighted laminar MRI
Joonas A. Autio1, Ikko Kimura1, Takayuki Ose1, Yuki Matsumoto1, Masahiro Ohno1, Yuta Urushibata2, Takuro Ikeda1, Matthew F. Glasser3,4, David C. Van Essen3, and Takuya Hayashi1
1Center for Biosystems Dynamics Research, RIKEN, Kobe, Japan, 2Siemens Healthcare K.K., Tokyo, Japan, 3Department of Neuroscience, Washington University Medical School, St. Louis, MO, United States, 4Department of Radiology, Washington University Medical School, St. Louis, MO, United States

Keywords: Blood Vessels, Blood vessels

Motivation: Although the brain's vascular network plays a crucial role in supplying oxygen and glucose while removing metabolic by-products to meet the high energy demands of neural information processing, our understanding of the vascular network architecture in the primate brain remains limited.

Goal(s): To address this issue, our study aims to explore the variability of the vascular network and its relationship to underlying neuroanatomy.

Approach: We investigate brain vascularity in macaque monkeys using ferumoxytol-weighted laminar MRI.

Results: We demonstrate that vascularity exhibits 3-fold variation across brain regions, moderate variability across cortical layers, distinct translaminar clusters, and strong association with neuron and synaptic densities.

Impact: Laminar ferumoxytol-weighted MRI shows considerable potential to delineate pial vessel network, intracortical feeding arteries and draining veins and density of capillary networks. The capillary density exhibits close association with the underlying neuroanatomy.

09:271130.
Imaging small intracortical blood vessels at 64 μm in-plane resolution in macaque monkey brain in vivo using a large-bore 7T MRI scanner
Jianbao Wang1,2, Yuhan Ma3, Yipeng Liu1, Libo Lin1,4, Avery J. L. Berman3,5, Saskia Bollmann6, Jonathan R. Polimeni7,8,9, and Anna Wang Roe1,2,4,10
1Department of Neurosurgery of the Second Affiliated Hospital, Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China, 2MOE Frontier Science Center for Brain Science and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China, 3Department of Physics, Carleton University, Ottawa, ON, Canada, 4College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China, 5Institute of Mental Health Research, Royal Ottawa Mental Health Centre, Ottawa, ON, Canada, 6School of Electrical Engineering and Computer Science, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, Australia, 7Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 8Department of Radiology, Harvard Medical School, Boston, MA, United States, 9Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States, 10Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China

Keywords: Blood Vessels, Vessels, Ultra-high field MRI

Motivation: Hemodynamics of the cerebral cortex are shaped by vascular architecture; however, it remains challenging to study the small intracortical vascular anatomy in vivo.

Goal(s): To test whether intracortical arterioles can be detected in vivo in non-human primates at 7 Tesla using a conventional human MRI scanner, and to study the organization of arterials and venules.

Approach: After conducting time-of-flight (TOF) contrast simulations, optimized TOF-MRA images from macaques were acquired using a 7T large-bore MRI scanner with 64-μm in-plane resolution.

Results: Intracortical arterioles and venules were reliably imaged and exhibited cortical area-specific differences in distribution. Imaging times were as fast as 10 minutes.

Impact: Using a standard human 7T MRI scanner, we illustrate that micron-scale intracortical arterioles are detectable non-invasively in vivo in primates. We suggest similar methods can be used to study human microvascular organization in health and disease.

09:391131.
Quantitative susceptibility mapping of the common marmoset brain at 9.4 T
Rakshit Dadarwal1 and Susann Boretius1
1Functional Imaging Laboratory, German Primate Center, Göttingen, Germany

Keywords: Large Animals, Nonhuman Primates, Susceptibility, Marmoset, Nonhuman primate, QSM, R2*, SWI, 9.4T, High-field

Motivation: Quantitative Susceptibility Mapping (QSM) is still not widely employed in non-human primates (NHP). Although it has been recently applied to cynomolgus and rhesus macaques, little attention has been given to other NHPs like marmosets. 

Goal(s): Our goal was to establish QSM in marmosets at 9.4 T. 

Approach: We conducted high-field MRI on 33 healthy marmosets to achieve superior spatial resolution and sensitivity. We evaluated the contrast-to-noise ratio in the QSM map for four subcortical structures and generated cortex intensity profiles.   

Results: In the marmoset brain, QSM provided excellent contrast of subcortical structure, various white matter tracts, and the cortex.

Impact: Establishing QSM in marmosets may be helpful to those interested in comprehending brain tissue structure and organization, refining brain parcellation, and facilitating procedures like MRI-guided stereotactic surgery, injections, and precise neuronal targeting.

09:511132.
Comparison of White Matter Maturation Rates in Young Rhesus Macaques and Humans
Carly Allen1, Douglas Dean2, Jason Moody3, Marissa DiPiero4, Nakul Aggarwal4, Ned Kalin5, Andrew Alexander1, and Steve Kecskemeti6
1Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 2Pediatrics, University of Wisconsin-Madison, Madison, WI, United States, 3Medicine, University of Wisconsin-Madison, Madison, WI, United States, 4Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, United States, 5Psychiatry, University of Wisconsin-Madison, Madison, WI, United States, 6Waisman Center, University of Wisconsin-Madison, Madison, WI, United States

Keywords: Large Animals, Nonhuman Primates, White Matter, Non-Human Primates, Modeling, Normal Development

Motivation: Non-human primates are thought to develop 3-4 times faster than humans based on sexual maturity and death; however, there has been a lack of quantitative data to support this ratio to describe brain development. 

Goal(s): Our goal was to find a quantitative relationship between the rate of white matter myelination in rhesus macaques and humans.

Approach: We compared rates of change in quantitative relaxometry MRI T1 values in six ROIs for rhesus macaques and human infants.

Results: We found a ratio ranging from 4.7 to 6.2 in the ROIs, corresponding to 4.7-6.2 times faster white matter myelination in rhesus macaques than humans.

Impact: By providing a quantitative approach to comparing early-life rhesus macaques white matter development with human infants, research that relates rhesus macaques and human brain development can make a more informed comparison, assisting researchers in translating results between species.

10:031133.
Neuroimaging of Serotonergic and Psychedelic Agonist Drug Challenges in Non-Human Primates
Ande Bagdasarian1, Kristian Larsen2,3, Patrick M. Fisher2,4, Hanne D. Hansen1,2, and Hsiao-Ying Wey1
1Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States, 2Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark, 3Department of Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark, 4Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark

Keywords: Pharmacology, Translational Studies, Psychedelics; phMRI; fMRI; Pharmacology; 5-HT2AR

Motivation: Acute effects of psychedelic drugs are under-reported in neuroimaging studies, warranting further investigation of their immediate pharmacology to explore the potential to monitor treatment response with imaging.

Goal(s): Our goal was to assess acute impacts of serotonergic (psychedelic and non-psychedelic) agonists on hemodynamics in non-human primates (NHP).

Approach: Pharmacological-MRI (phMRI) was used to measure cerebral blood volume (CBV) changes by psilocybin, lisuride and 25CN-NBOH.

Results: Psilocybin and lisuride induced bi-phasic hemodynamic response, whereas 25CN-NBOH was monophasic. Bi-phasic phenomena may be due to non-selectivity of agonist drugs. Elevated CBV at higher psilocybin doses persists longitudinally, while lisuride and 25CN-NBOH modulations trend toward baseline.

Impact: Bi-phasic signal profiles and downstream impacts to cerebral hemodynamics may reflect non-selective targeting of psilocybin and lisuride, highlighting the sensitivity of phMRI in drug evaluation.