bluuebunny/crossref_metadata_2025 huggingface dataset:
Unveiling Mesoscale Finger-specific Neural Circuits through Near-infrared Stimulation and fMRI Mapping
Authors: Qu Boyi , He Tingting , Wang Haiming , Tang Zheng , Lyu Zhuyuan , Roe* Anna , Lai* Hsin-Yi
Published: November 2024

Motivation: The dexterity of individuated finger movements is fundamental to daily hand use; yet specific brain networks serving each finger remains poorly understood. Goal(s): Our objective is to unravel mesoscale connections associated with finger-specific neural circuits. Approach: In 2 macaque monkeys, single digit locations were functionally mapped in cortical areas 3b via fMRI. Pulsed INS (infrared neural stimulation) targeted to these sites elicited mesoscale BOLD activation at functionally connected sites resulting in brainwide single digit networks. Results: INS-induced BOLD activations revealed the distinct networks associated with each finger. Index finger connected with sensorimotor, multisensory and emotion circuits, supporting flexibility and stability in fine movement. Impact: This research identifies specific brain networks underlying single digit maps in SI, and will be relevant for understanding hand dexterity, neurorehabilitation, and prosthesis development.
Contrast Discrimination in Awake Macaque with 7T MRI
Authors: Shi Sunhang , Chen Meixuan , Zhai Chenxi , Qian Meizhen , Wang Jianbao , Tanigawa Hisashi , Roe Anna Wang
Published: November 2024

Motivation: This research aims to investigate visual perception in awake macaques using 7T MRI, enhancing our comprehension of BOLD responses during a contrast discrimination task and developing a quantifiable method for neuromodulation. Goal(s): The specific objectives include directly observing BOLD responses at mesoscale during a contrast discrimination task. Approach: The study utilized 7T MRI while macaques performed a 2AFC task, allowing simultaneous stimulus presentation and BOLD response measurement. Results: The study successfully mapped BOLD responses during behavioral tasks, revealing contrast sensitivities in the visual cortex. Notably, it identified BOLD signal decreases in ambiguous contrast conditions, shedding light on perceptual uncertainty in stimulus discrimination. Impact: These findings may advance quantification of behavioral an neural processes, helping to bridged the gap between human non-invasive and monkey invasive studies.
Functional connectivity of medial pulvinar to limbic system in macaque monkey revealed by INS-fMRI
Authors: Feng Yuqi , Yao Songping , Shi Sunhang , Liu Meilan , Wang Jianbao , Roe Anna
Published: November 2024

Motivation: To understand the circuitry underlying the pulvinar and limbic cortical areas in the brain. Goal(s): To map at mesoscale functional connections between medial pulvinar (PM) and insular and cingulate cortices in Macaque monkey. Approach: Infrared neural stimulation was delivered via optic fibers to sequential sites in PM in Macaques and BOLD responses at connected sites mapped in 7T MRI. Results: We find connectivity of PM with cingulate cortex was patchy and columnar, with sequential sites in PM producing mediolateral topographic activation. A functional topology of these patches was observed in cingulate. Impact: The specificity and mesoscale nature of functional connections from medial pulvinar to limbic systems, providing new treatment ideas for mental disorders.
Multiple Loci for Foveolar Vision in Macaque Monkey
Authors: Qian Meizhen , Wang Jianbao , Gao Yang , Liu Yin , Zhou Dengfeng , Zhang Xiaotong , Hu Jiaming , Roe Anna
Published: November 2024

Motivation: Foveolar vision (central 1º of vision) is important for many visual behaviors; however, its cortical representation is poorly understood. Goal(s): To understand the functional organization of foveolar visual cortex in macaque monkey. Approach: Use human 7T to conduct fMRI of foveal visual cortex at submillimeter resolution (0.6mm in-plane) in awake fixating macaque monkeys. Results: We found at least 8 distinct loci of foveolar representation per hemisphere, one each for dorsal and ventral V1/V2, V2/V3, V3/V4, V4/TEO. These loci surround a substantial cortical territory (the foveolar core) which lies outside topographic cortex. Impact: The foveolar core may represent a higher-order specialization for foveal behaviors.
Acquisition and characterisation of sub-millimetre resolution GE-BOLD laminar fMRI data at 3T and 7 T
Authors: Kashyap Sriranga , Kim Seong-Gi , Uludağ Kâmil
Published: November 2024

Motivation: To explore the potential of layer-specific imaging of the brain at standard clinical field (3T) and ultra-high field strengths (7T)Goal(s): To assess the feasibility of sub-millimetre BOLD fMRI at 3T compared to 7T and characterise activation maps and laminar profilesApproach: 12 healthy participants scanned using product 2D-EPI at four resolutions on both 3T and 7T scanners. Data were meticulously processed using ANTs and AFNI following NORDIC-PCA denoising. Results: We demonstrate that sub-millimetre GE-BOLD fMRI at 3T is feasible using a standard fMRI sequence, has sufficient tSNR and reliable BOLD activation maps. Impact: Our work broadens accessibility to high-resolution fMRI at 3T. Thus, encouraging new directions in neuroimaging and enabling a deeper understanding of human brain function in health and disease, impacting not only neuroscientists but also the broader scientific and medical communities.
Atypical functional connectome hierarchy in early-blind adolescents
Authors: Zhou Zhifeng
Published: November 2024

Motivation: Blind people are a good biological model for studying brain plasticity. Goal(s): e examined the brain reorganization of the macroscale hierarchy in early-blind adolescents (EBA) compared with normal-sighted controls (NSC). Approach: Twenty EBA and 20 age-and sex-matched NSC were included. We calculated the vertex-wise functional connectomes of each individual and compared the top 2 gradient scores between the EBA and NSC groups. Results: The comparison between groups revealed increases in the first two gradients in the visual, sensorimotor, control, and default-mode networks in EBA. Impact: The macroscale integration and segregation in unimodal and transmodal network is converged and strengthened in EBA relative to NSC.
Altered static and dynamic functional network connectivity in individuals with subthreshold depression: a resting-state fMRI study
Authors: Liao Dan , Liu Xinfeng , Guo Zhipeng , Wang Rongpin
Published: November 2024

Motivation: identifying the neural pathology mechanisms has the potential value to elucidate risk factors and prognostic markers for subthreshold depression(StD)Goal(s): FNC is a useful imaging tool in detecting the neuro-mechanism of the brain Approach: This study involved in the static functional network connectivity (sFNC) and dynamic functional network connectivity (dFNC) to investigate the FNCdifferences between the StD and HCs groupsResults: StD demonstrated altered FNC in executive control network (ECN), default mode network (DMN), sensorimotor network (SMN) and dorsal attentional network (DAN), in addition, Std had increased mean dwell time and fraction time in a weak connected state concerning the dFNC analysis. Impact: The sFNC and dFNC findings could enrich our understanding of the large-scale resting-state FNC abnormalities in StD individuals, which could provide insights for a better understanding of the behind neural mechanisms
Integrated Resting-state and Breath-hold Paradigm for Reliable Cerebrovascular Reactivity Mapping and Functional Connectivity
Authors: Zhang Zhanyan , Zhang Jinyuan , An Jing , Zhang Peng , Zhang Zihao
Published: November 2024

Motivation: There is a lack of head-to-head evaluation of resting-state (RS) and breath-hold (BH) cerebrovascular reactivity (CVR). Goal(s): Propose an integrated paradigm combining RS- and BH-BOLD acquisition in a single run, and evaluate the reliability of RS- and BH-CVR mapping with this protocol. Approach: Combined RS- and BH-BOLD data were acquired on a 7T scanner. CVR mappings of various time windows were calculated and compared. Results: RS-BOLD can be calculated for CVR mapping but is susceptible to BOLD signal outliers. BH-BOLD produces stable CVR mappings with higher dynamic range. The integrated paradigm guarantees reliable BH-CVR mapping and RS-fMRI analysis. Impact: The introduction of the RS-BH paradigm offers an avenue for reliable CVR mapping with high dynamic range and is compatible with conventional RS-fMRI analysis.
Neural Correlates of Transcutaneous Vagal Nerve Stimulation: Functional MRI Effects of Anatomical Site and Waveform Parameters
Authors: Drenthen Gerhard , Beckers Abraham , Jacobs Heidi , Ruffle James , Jansen Jacobus , Backes Walter , Priovoulos Nikos , Keszthelyi Daniel
Published: November 2024

Motivation: There is marked heterogeneity in transcutaneous vagal nerve stimulation (tVNS) based on the anatomical site (cervical/auricular), and the waveform parameters (fixed/variable frequency) of the stimulation. Goal(s): To explore the functional brain differences between cervical vagal nerve stimulation and auricular vagal nerve stimulation. Approach: Ultra-high field functional neuroimaging is performed of the neural correlates of tVNS with disparate anatomical sites and electrical waveform characteristics during rest in healthy participantsResults: Auricular stimulation with a variable frequency was shown to result in a significant decrease of the BOLD response in the amygdala and insular cortex compared to sham stimulation. Impact: There exist multiple knowledge gaps in the use of tVNS, which hinders the advancement of tVNS applications. This explorative study has shown the differences in neuronal response of auricular and cervical stimulation with fixed and variable frequencies.
Decoding the neural representation of value in schizophrenia with negative symptoms
Authors: Forouhandehpour Reihaneh , Horga Guillermo , Cassidy Clifford
Published: November 2024

Motivation: The neural mechanisms underlying motivation and pleasure deficits in schizophrenia have not yet been elucidated. Goal(s): We aimed to develop a method to disentangle different aspects of value-based decision making to understand these deficits in schizophrenia. Approach: We developed a novel fMRI task and combined it with machine learning approaches to effectively measure multiple components of value-based decision making. Results: Our preliminary results revealed that patterns of brain activity in the value regions of the brain (ventromedial PFC and ventral striatum) are predictive of healthy individuals’ decisions; however, such patterns do not provide value representation to support decision making in schizophrenia. Impact: Neural patterns in the value regions of the brain were shown to not represent value to support decision making in schizophrenia. These findings will provide targets for treatment developments for motivation and pleasure deficits in schizophrenia and other psychiatric conditions.
Early Detection Of Heart Failure By Visualizing Redox Metabolism Using In Vivo Dynamic Nuclear Polarization MRI
Authors: Ichihashi Koki , Hyodo Fuminori , Elhelaly Abdelazim , Tomita Hiroyuki , Fujimoto Keita , Noda Yoshifumi , Kato Hiroki , Matsuo Masayuki
Published: November 2024

Motivation: The diagnosis of heart failure is based on clinical symptoms because noninvasive methods for early diagnosis are still insufficient. Goal(s): Considering reactive oxygen species contribute to heart failure, we hypothesized much earlier signs of heart failure could be captured by focusing on redox metabolism. Approach: We used a doxorubicin-induced mouse model of heart failure and analyzed at an early stage. To visualize redox metabolism, we used in vivo dynamic nuclear polarization MRI. We also evaluated the cardiomyocytes microscopically. Results: The intracardiac redox metabolism was enhanced in 30 min after doxorubicin administration compared to the control group although no significant cardiomyocyte changes were observed. Impact: In the early stages of heart failure, redox metabolism is altered even before the morphological changes are observed microscopically. These data provide a technique for detecting heart failure earlier and less invasively than conventional testing methods.
A deep neural network for Oxygen Extraction Fraction (OEF) mapping based on No Training
Authors: Ally Ada , Cho Junghun
Published: November 2024

Motivation: Quantitative mapping of oxygen extraction fraction (OEF) is critical to evaluate brain tissue viability and function in neurologic disorders. A recent deep learning-based OEF technique, namely QQ-NET, provided OEF maps sensitive to disease-related abnormalities. However, QQ-NET suffers from training data dependency and requires extensive amount of training data. Goal(s): Our goal is to resolve the training data dependency issue. Approach: We developed a novel deep learning scheme, namely QQ-NTD, which minimizes the biophysics model fidelity on each single dataset. Results: The proposed QQ-NTD provided a more accurate OEF than QQ-NET. Impact: With no need for extensive training and independence from input imaging parameters, our novel deep learning approach, QQ-NTD, can be used readily used to obtain OEF maps in clinical setting.
Development of a DNP-MRI molecular probe for detecting dipeptidyl peptidase-4 activity in vivo based on the substrate recognition mechanism.
Authors: Goto Akihito , Yatabe Hiroyuki , Koyasu Norikazu , Yamamoto Kazutoshi , Krishna Mural , Saito Keita , Takakusagi Yoichi , Saito Yutaro , Sando Shinsuke
Published: November 2024

Motivation: Dipeptidyl peptidase-4 (DPP-4) is a biologically important peptidase known as a biomarker and therapeutic target for type 2 diabetes and cancers. Therefore, detection of DPP-4 activity can be a useful method for early diagnosis and treatment efficacy assessment. Goal(s): Development of a DNP-MRI molecular probe for detecting DPP-4 activity in vivo Approach: We performed molecular designs of DNP-MRI molecular probes for meeting physicochemical properties. For evaluation of enzymatic reactivity of the probes, enzymatic reaction parameters (Km, kcat) were measured. The optimized probe was applied for DNP-MRI experiments using mice. Results: We developed a DNP-MRI molecular probe to detect DPP-4 activity in vivo. Impact: With design strategy based on recognition mechanism, we have developed a DNP-MRI molecular probe against DPP-4, which has been difficult to develop so far. New probe enables detection of DPP-4 activity in vivo and will be useful for medical applications.
Manganese-enhanced gene expression MRI using Zip14
Authors: Rallapalli Harikrishna , Koretsky Alan
Published: November 2024

Motivation: Zip14 is an in vivo MRI-visible gene expression reporter system capable of producing focal signal changes without administration of additional contrast agents. However, it is not yet known how much contrast-enhanced MRI will improve sensitivity for Zip14 expression. Goal(s): Our goal was to understand how systemically delivered manganese (Mn2+)-enhanced MRI (MEMRI) would improve Zip14 contrast. Approach: Zip14 was expressed in the mouse brain and MRI was performed as previously described. MnCl2 was injected intraperitoneally and MEMRI was performed. Results: MEMRI improved Zip14 contrast by approximately four-fold at the injection site, by two-fold at sites of anterograde tracing, and revealed previously undetectable tracing sites. Impact: Although supplemental Mn2+ is not required to observe T1-weighted MRI signal enhancement produced by Zip14 expression, it can significantly improve contrast. Increased sensitivity for Zip14 expression with MEMRI will improve measurement of neural connectivity, degeneration, and plasticity in vivo.
Hyperpolarized Xe MRI to Evaluate Lung Function in Patients with History of BPD
Authors: Willmering Matthew , Hysinger Erik , Janjindamai Chawisa , Soderlund Stephanie , Hussain Riaz , Plummer Joseph , Bdaiwi Abdullah , Critser Paul , Parikh Nehal , Amin Raouf , Woods Jason
Published: November 2024

Motivation: With improved neonatal care and increased survival of very preterm infants, the incidence of bronchopulmonary dysplasia (BPD, or chronic lung disease of prematurity) has increased. Goal(s): To evaluate Xe gas-exchange MRI by investigating success rates, sensitivity, and correlations with clinical demographics and pulmonary function testing. Approach: In 24 patients, Xe ventilation, restricted diffusion, and gas-exchange MRI were collected along with pulmonary function testing and electronic health records. Results: We found hyperpolarized Xe-MRI detects ventilation, lung microstructure, and gas-exchange abnormalities in 53%, 59%, and 82% of patients, respectively. Additionally, ventilation obstruction worsened with age, and two imaging phenotypes were detected. Impact: Hyperpolarized Xe-MRI detected significant ventilation defects in 53% and lung microstructure abnormalities in 59% of bronchopulmonary dysplasia patients. Gas-exchange MRI revealed two phenotypes, with abnormalities in membrane-uptake (82%), RBC-transfer (65%), and RBC:Membrane ratio (29%).
129Xe MRS Biomarkers Predict 6-week Response to ICS/LAMA/LABA in Moderate Asthma
Authors: Kooner Harkiran , Sharma Maksym , Mozaffaripour Ali , Tcherner Sam , Yamashita Cory , Parraga Grace
Published: November 2024

Motivation: 129Xe MRS quantifies pulmonary gas-exchange by probing inhaled 129Xe transfer from the alveolar-membrane to the red-blood-cells (RBC). Recent work suggested a vascular response to asthma therapy, quantifiable using 129Xe MRS. Goal(s): We aimed to examine if 129Xe MRS measurements were predictive of significant 6-week response to ICS/LAMA/LABA in moderate asthma patients. Approach: 129Xe MRS and pulmonary function measurements were acquired prior to and following 6-weeks of therapy. Results: 129Xe RBC:membrane, measured prior to treatment, was predictive of response to ICS/LAMA/LABA at 6 weeks, measured using the fraction-of-exhaled nitric-oxide and the ratio of forced-expiratory-volume in 1-second to forced-vital-capacity. Impact: For the first time, 129Xe MRS RBC:membrane has been shown to predict early (6-week) response to ICS/LAMA/LABA in moderate asthma. 129Xe MRS uncovered a novel pathophysiology in asthma patients, with potential for consideration as a new treatable target.
Development of a transmit gain calibration method using the Bloch-Siegert shift for nonproton hyperpolarized MRI on a preclinical 7T scanner
Authors: Harlan Collin , Michel Keith , Bankson James
Published: November 2024

Motivation: Transmit gain calibration is necessary for nonproton hyperpolarized MRI to accurately calibrate excitation angles. Goal(s): To implement a phase-based TG calibration method using the Bloch-Siegert shift for nonproton HP MRI on a preclinical 7T scanner. Approach: An off-resonance Fermi-shaped Bloch-Siegert pulse follows directly an excitation pulse. Percent difference between our measured Bloch-Siegert TG calibration factors and the validation TG calibration factors for 1H and 13C were calculated. Results: Our method allows for fast, accurate, and robust TG calibration of preclinical nonproton HP MRI studies with minimal error (<5%) for 1H and 13C. Impact: This method will facilitate efficient transmit calibration for 13C and HP 129Xe MRI on a preclinical 7T scanner, where limited bore size and the inability to easily implement a thermal calibration phantom can make 129Xe TG calibration a challenge.
129Xe HyperCEST Imaging of a Novel R3-Noria-methanesulfonate Supramolecular Cage using a 3.0 T Clinical MRI
Authors: Batarchuk Viktoriia , Shepelytskyi Yurii , Grynko Vira , Kovacs Antal , Hodgson Aaron , Rodriguez Karla , Aldossary Ruba , Talwar Tanu , Hasselbrink Carson , DeBoef Brenton , Albert Mitchell S.
Published: November 2024

Motivation: In the setting of molecular MRI, designing a contrast agent that can be applied in clinical studies and which offers high sensitivity poses a significant challenge. Goal(s): We aimed to demonstrate a novel water-soluble R3-Noria-MeSO3H macrocycle as a viable supramolecular cage agent for 129Xe molecular imaging. Approach: Hyperpolarized 129Xe chemical exchange saturation transfer MR imaging and spectroscopy were conducted in vitro using a 3.0T clinical MRI scanner. Results: We demonstrated that R3-Noria-MeSO3H produces a superior HyperCEST effect and investigated its dependence on concentrations in various aqueous solutions. Impact: The introduction of the novel R3-Noria-MeSO3H macrocycle for HP 129Xe HyperCEST imaging marks a critical milestone, establishing a new frontier in 129Xe molecular imaging with heightened sensitivity and potential for advancing clinical applications in diagnostic precision and therapeutic monitoring.
Assessing Regional Lung Function with Chemical Shift Imaging - Chemical Shift Saturation Recovery (CSI-CSSR) Using Hyperpolarized Xenon-129
Authors: Ruppert Kai , Loza Luis , Chen Jiawei , Amzajerdian Faraz , Hamedani Hooman , Ismail Mostafa , Duncan Ian , Profka Harrilla , Kadlecek Stephen , Rizi Rahim
Published: November 2024

Motivation: Chemical shift saturation recovery (CSSR) MR spectroscopy using hyperpolarized xenon-129 (HXe) is sensitive to abnormal lung function but lacks regionality. Goal(s): Add regional information to CSSR MR spectroscopy with variable echo time (TE) chemical shift imaging (CSI). Approach: Comparison of CSI-CSSR to global CSSR measurements in the lungs of a healthy and an irradiated rat. Results: CSI-CSSR yields results comparable to whole-lung CSSR spectroscopy but with added regionality. Impact: CSI-CSSR allows the regional quantification of apparent alveolar septal wall thickness, T2*, and resonance frequency shifts. This approach greatly enhances the sensitivity for the detection of abnormal xenon gas-exchange processes in heterogeneous lung disease.
Testing the utility of Dynamic Susceptibility Contrast (DSC)-Perfusion toolbox for mapping the characteristics of mouse brain perfusion
Authors: Jain Shreya , Kurniawan Nyoman
Published: November 2024

Motivation: Perfusion studies using DSC-MRI offer insights into vascular aspects of cerebral pathophysiology by allowing us to estimate viable perfusion characteristics. Goal(s): Previous studies have shown successful implementation of DSC MRI toolbox to characterise human brain perfusion, but its application to animal data remains unexplored. Our goal is to characterize perfusion parameters in mouse model using DSC-MRI-toolbox. Approach: We slightly modified and implemented DSC-MRI-toolbox to meaure CBV, CBF and MTT in different regions of mouse brain such as cortex, hippocampus and thalumus. Results: Initial data analysis shows a successful implementation of the DSC-MRI-toolbox and allowing us to estimate perfusion parameters in preclinical data. Impact: A successful implementation of DSC-MRI toolbox in mouse models will allow us to estimate perfusion parameters such as CBV, CBF, MTT and CBV with leakage correction, which will be important for characterising tissue viability in stroke and brain injury models.
Concurrent Dual-Contrast Enhancement Using Fe3O4 Nanoparticles to Achieve a CEST Signal Controllability
Authors: Hu Feixiang , Wang Dan , Ma Xiaowen , Hu Tingdan , Yue Yali , Wu Pu-Yeh , Tang Wei , Tong Tong , Peng Weijun
Published: November 2024

Motivation: The unique microenvironment of tumors making detection of microenvironmental alterations a valuable asset for early diagnosis of tumors. Goal(s): This study focuses on exploring impact of Fe3O4 NPs on changes in the tumor microenvironment's acidity. Approach: By combining them with CEST exogenous contrast agent, we evaluated the feasibility of dual-contrast imaging. Results: In vitro MRI results suggest that Fe3O4 NPs can act as stable reference agents under varying pH conditions, providing negative contrast for T2-weighted MRI. The CEST effect shows a strong correlation with pH, allowing for quantitative assessment of pH shifts in tumor microenvironment, and can be controlled by adjusting Fe3O4 concentration. Impact: These preliminary findings represent an initial stride toward dual-contrast imaging involving CEST and T2 contrast agents, with the potential for further expansion in future in vivo investigations.
Noninvasive Early Detection and Stage of Chronic Lung Diseases with Precision MRI (pMRI)
Authors: Li Dongjun , Gui Zongxiang , Qiao Jingjuan , Bamishaye Sophia , Yang Jenny
Published: November 2024

Motivation: MRI diagnosis of lung has a limitation due to the air in the lungs which prevents the water signals. We use precision MRI to image the small lesions or fibrosis in the lung. Goal(s): Our goal is to quantitatively stage the lung diseases by MRI contrast agents. Approach: Our novel MRI contrast agent is biomarker specific which enables it target to the lung lesions or fibrosis. Results: We are able to image the lung cancer and metastasis as well as lung fibrosis using our developed MRI contrast agent. Impact: The imaging of lung tumor lesion or fibrosis is always hindered by the lung features. Our novol contrast agents enable us to image the lung diseases at early stages.
Comparison of Spontaneous Brain Activity between Hippocampal Sclerosis and MRI-Negative Temporal Lobe Epilepsy
Authors: Song Chengru , Zhang Xiaonan , Han Shaoqiang , Ma Keran , Mao Xinyue , Wang Mengzhu , Zhang Yong , Cheng Jingliang
Published: November 2024

Motivation: There has been controversy regarding the pathophysiological basis of MRI-negative temporal lobe epilepsy (TLE-N) and its similarities and differences relative to TLE with hippocampal sclerosis (TLE-HS). Goal(s): Static and dynamic abnormalities of spontaneous brain activity (SBA) in TLE-HS and TLE-N were examined. Approach: Six static SBA indicators and corresponding temporal dynamic indicators were calculated using a sliding window approach, then compared. Results: Patterns of change in SBA abnormalities were generally similar between TLE-HS and TLE-N groups; they were more pronounced in the TLE-HS group. VMHC in the hippocampus showed promise for differential diagnosis. Many indicators were correlated with cognition. Impact: The use of static and dynamic metrics can convey a more detailed and reliable description of abnormal neuronal activity, facilitating exploration of epileptic activity and cognitive impairment mechanism in MRI-negative temporal lobe epilepsy (TLE) and TLE with hippocampal sclerosis.
Mapping Cortical Fiber Orientations in Human Focal Cortical Dysplasias Using High-Resolution Diffusion MRI
Authors: Dai Erpeng , Tian Qiyuan , Liao Congyu , Razavi Babak , Parvizi Josef , Buch Vivek , Setsompop Kawin , Zeineh Michael , McNab Jennifer
Published: November 2024

Motivation: Detecting focal cortical dysplasia (FCD) is critical for effective neurosurgical intervention but remains technically challenging. Recent MRI technical advancements may provide new opportunities for FCD detection. Goal(s): To determine the potential of high-resolution DTI to map cortical fiber orientation changes in FCD. Approach: High-resolution (1 mm isotropic) DTI data were acquired on six epilepsy patients with suspected FCD. A surface-based analysis workflow was built to assess the principal fiber orientations against the cortical surface. Results in FCD were compared to the contralateral homologous region. Results: All patients show differences in cortical fiber orientations between FCD and the contralateral presumed normal cortex. Impact: Our study documents that high-resolution diffusion MRI can detect cortical fiber orientation changes in human FCD in vivo, which can be a novel surrogate maker for FCD detection.
Regional cortical thinning and aberrant cortical folding in sleep-related hypermotor epilepsy
Authors: Pu Huaxia , Wu Xintong , Wang Liping , Tan Qiaoyue , Wang Weina , Wan Xinyue , Su Xiaorui , Zhang Simin , Yue Qiang , Gong Qiyong
Published: November 2024

Motivation: We aimed to investigate the neuromorphometric abnormalities and their relationship with clinical characteristics in patients with sleep-related hypermotor epilepsy (SHE) by structural MRI. Goal(s): This is the first study to explore cortical microstructural alterations using surface-based morphometry (SBM) analysis in SHE patients. Approach: SBM analysis was used to evaluate cortical thickness, fractal dimension, gyrification, and sulcal depth. Results: SHE patients exhibited decreased cortical thickness in the left inferior-parietal, right superior-parietal, bilateral lateral-occipital, left fusiform regions, and decreased sulcal depth in the right precentral and postcentral gyri compared to controls. The cortical thickness of left inferior-parietal region was negatively correlated with illness duration. Impact: These findings demonstrate that aberrated thinning and folding of local cerebral cortices existed in SHE and may be associated with clinical hypermotor semiology. These cortical morphological variations might contribute to understand epilepsy network disturbances and underlying neuropathologic mechanism of SHE.
Machine Learning-Based Lateralization of Mesial Temporal Lobe Epilpepsy Using ASL MRI
Authors: Rahimzadeh Hossein , Nazem-Zadeh Mohammad-Reza , Kamkar Hadi , Khanghahi Seyed Alireza
Published: November 2024

Motivation: Utilizing perfusion features to differentiate left and right mesial temporal lobe epilepsy (mTLE) using machine learning. Goal(s): The study aims to assess ASL MRI's perfusion analysis ability to identify abnormalities in brain regions for distinguishing between mTLE cases and normal cohorts. Approach: Cerebral blood flow obtained features used by different machine learning classifiers to separate right and left mTLE form control cohort. Results: The utilization of CBF features proved valuable and effective in the machine learning-based classification of right and left mTLE data from the control cohort. Impact: This study's outcomes benefit medical professionals and drug-resistant mTLE patients by expediting surgical assessments and enhancing treatment outcomes through improved lateralization and epilepsy classification.
Investigating ASL-MRI as a Complementary Modality for 18F-FDG PET in Identifying Mesial Temporal Lobe Epilepsy Laterality in Grey Matter
Authors: Nazem-Zadeh Mohammad-Reza , Rahimzadeh Hossein , Kamkar Hadi , Hoseini-Tabatabaei Narges , Hashemi-Fesharaki Sohrab , Habibabadi Jafar Mehvari
Published: November 2024

Motivation: Using non-invasive ASL-MRI as a substitute of 18F-FDG PET for identification of epileptogenic zone in mTLE patientsGoal(s): This study aims to check if there is a correlation between the CBF of ASL-MRI and metabolic data from 18F-FDG PET. Approach: Brain division into 12 ROIs, including key areas like the amygdala and hippocampus, used BASIL and FSL tools for CBF and SUVr extraction. Used Pearson's and Spearman's rank correlation of SPSS for correlation analysis. Results: Significant CBF and SUVr correlations in middle temporal gyrus, hippocampus, and superior temporal found in mTLE patients. Impact: This study affects mTLE patients' accurate and rapid epileptogenic foci location.
Brain metabolism in patients with Tuberous Sclerosis Complex
Authors: Senapati Dillip K. , Zöllner Helge , Özdemir İpek , Barker Peter , Gill Ryan , Lin Doris
Published: November 2024

Motivation: To better understand the underlying pathophysiology of brain lesions in patients with tuberous sclerosis complex (TSC). Goal(s): To apply both conventional and spectrally-edited MR spectroscopic imaging (MRSI) to patients with TSC, and to quantify metabolite levels in lesions and normal-appearing brain. Approach: Anatomical MRI and high-resolution MRSI was performed in 9 subjects with TSC at 3T. Spectra were quantified in lesions and normal appearing brain. Results: Lesion metabolite levels expressed relative to total creatine showed significant decreases in GABA+ , tNAA and tCho (p < 0.05) compared to normal-appearing white matter. The ratio of GABA+/Glx was also significantly lower in lesions (p = 0.03). Impact: These preliminary data in 9 subjects suggest that TSC lesions are characterized by neuronal loss or dysfunction, and possible neurotransmitter imbalance. Future work is required to relate these findings to neurological symptoms, including seizure frequency and cognitive impairment.
Contactless Cardiac Triggering Using Camera PPG in Cardiac MR
Authors: Weiss Steffen , Sénégas Julien , Stehning Christian , Brinker Bert den , Blom Krelis , Kok Annette , Possanzini Cecilia , Smink Jouke , Springorum Rudolf , Ramamurthy Pradhayini , Wuelbern Jan Hendrik
Published: November 2024

Motivation: Contactless cardiac triggering makes cardiac and cardiovascular MRI (cMRI) more accessible by improving patient comfort, reducing complexity, facilitating swift workflow, and increasing patient throughput. Goal(s): In this work we demonstrate feasibility of contactless cardiac trigger detection using an in-bore camera in two routine cMRI sequences. Approach: Building on an existing in-bore camera hardware we developed a cardiac trigger detection method for cMRI that extracts a remote photoplethysmography (rPPG) signal acquired at the patient’s forehead. The quality of the acquired MR images is compared with ECG triggering. Results: rPPG and ECG triggering delivered comparable image quality in the majority of study volunteers. Impact: The presented work provides evidence that cMRI is feasible with contactless, camera-based cardiac signal detection. The proposed method allows cMRI without placement of ECG electrodes, thus increasing accessibility of cardiac MR.
A novel sequence for Simultaneous imaging of cerebral Arteries and VEins (SAVE) based on velocity-selective arterial spin labeling
Authors: Liu Lixin , Wang Lili , Chu Ying Hua , Wang Jian , Li Hao , Wang He , Chen Zhensen
Published: November 2024

Motivation: The conventional velocity-selective ASL-based (VSASL) MRA couldn’t separate arteries and veins unless additional module is used, which would cause long scan time. In addition, its acquisition efficiency is low since a long waiting time for blood refreshing. Goal(s): To proposed a VSASL-based sequence for Simultaneous imaging of cerebral Arteries and VEins (SAVE). Approach: SAVE uses the waiting period between consecutive shots of VSASL MRA to acquire SWI data. VSASL MRA/MRV were obtained by subtracting Control images from Label images, while SWI images were averaged to increase SNR. Results: SAVE-VSASL MRA/MRV can well depict arteries and veins, and SAVE-SWI MRV could depict veins well. Impact: The novel sequence can obtain decent VSASL MRA/MRV and SWI MRV images. The combination of the VSASL MRA/MRV and SWI MRV in SAVE should allows separation of arteries and veins by post-processing, that may be useful in clinical settings.
Arbitrary Pulse Sequence Execution with Pulseq on Philips MRI Scanners
Authors: Shaik Imam Ahmed , Liu Qiang , Robison Ryan , Zhao Yansong , Zaitsev Maxim , Nielsen Jon-Fredrik , Rathi Yogesh , Westin Carl-Fredrik , Bilgic Berkin , Gagoski Borjan , Ning Lipeng , Ellison Andrew , Rushmore Richard J , Grissom William A
Published: November 2024

Motivation: To enable execution of open-source vendor-agnostic pulse sequences on Philips MRI scanners. Goal(s): To develop a Pulseq interpreter for Philips scanner. Approach: An intelligent Philips Pulseq interpreter, denoted "p2p" (Pulseq to Philips), was implemented in MATLAB. It converts Pulseq-generated .seq files into a format compatible with Philips sequence objects. Results: The p2p interpreter was tested with sequences that included arbitrary gradient waveforms including custom spiral waveforms and crusher waveforms spelling out the words ‘Philips Pulseq’, GRE and DW-EPI scans evaluated in phantoms and in vivo. Impact: Open-source Pulseq format sequences can be executed with minimal adaptations on Philips scanners. The p2p Pulseq Philips interpreter completes the set of interpreters required to implement harmonized pulse sequences across the three major vendor platforms.
Towards brain blood metabolite measurement using MRS with pseudo-continuous arterial spin labeling
Authors: Truong Peter , Okell Thomas , Near Jamie
Published: November 2024

Motivation: Single voxel spectroscopy allows us to measure the metabolite signal within a voxel in the brain. There are strides to mathematically segment this signal based on tissue type: grey matter, white matter, and cerebral spinal fluid. However, blood is also an important component to this signal as the brain is heavily vascularized. Goal(s): We wish to better understand the MR signal contribution coming from blood in the brain. Approach: Borrowing from imaging-based pCASL, we’ve combined the RF tagging pulse train to a standard PRESS sequence, creating SVS-pCASL. Results: With our preliminary testing, we observed an ASL effect on the unsuppressed water signal. Impact: MRS provides us with useful information regarding the metabolite signals. However, one key component is overlooked, blood. Combining pCASL RF tagging with PRESS to create SVS-pCASL, our preliminary results show an ASL effect on unsuppressed water signal in the brain.
Modified Three-dimensional Double-echo Steady-state Echo-planar Imaging with Fly-back Gradients for Quantitative Susceptibility Mapping
Authors: Han Silu , Sonderer Christa , Chen Nan-kuei
Published: November 2024

Motivation: The selection of cerebrospinal fluid (CSF) as a zero-reference can yield significant and interpretable susceptibility measurements in quantitative susceptibility mapping (QSM). Goal(s): Our goal is to develop a 3D dual-pathway sequence capable of achieving acquisition of multi-contrast images with a reduced scan time and improving image quality. These images will be used in selecting the zero reference in QSM. Approach: We implement a 3D double-echo steady-state echo-planar imaging (DESS-EPI) sequence with fly-back gradients, designed to generate multi-contrast images while eliminating Nyquist artifact. Results: Our preliminary findings indicate the feasibility of utilizing multi-echo images in QSM and global CSF segmentation. Impact: The use of global CSF as a reference in QSM can enhance susceptibility measurements. The development of our modified 3D DESS-EPI sequence improves image quality, reduces scan time, and shows promise for global CSF segmentation in QSM.
Blood-to-CSF Water Exchange Time Estimation Using a multi-PLD, multi-TE 3D RARE Stack-of-Spirals ASL Sequence
Authors: Li Bo , Liu Hangfan , Li Yiran , Taso Manuel , Petitclerc Léonie , Osch Matthias , Vidorreta Marta , Fernández-Seara María , Tisdall M. Dylan , Chang Yulin , Detre John , Wang Ze
Published: November 2024

Motivation: To assess the blood-CSF barrier on a Siemens platform using a multi-TE 3D RARE stack-of-spirals ASL sequence. Goal(s): To obtain high-quality fitted blood-to-csf time images. Approach: A 3D RARE pCASL sequence with multiple-TE acquisitions was used to collect ASL images. To cope with the low SNR issue in blood-CSF barrier ASL imaging, a denoising technique of locally adaptive low rank regularization with collaborative data selection was applied to images. Results: The fitted blood-to-csf time images generated from denoised control and label images showed significantly improved image quality. The Bland-Altman Plot shows a good agreement between the test and retest scans using the sequence. Impact: Blood-CSF barrier ASL implemented in the Siemens platform showed good test-retest reliability with the help of advanced denoising. The denoising technique can be used for ASL applications to provide high-quality images.
Echo time optimization of 2HG-edited MRS and T2 determination of tumor metabolites at 3T
Authors: Chan Kimberly , Hapani Rutul , Maher Elizabeth , Patel Toral , Henning Anke
Published: November 2024

Motivation: 2HG is an important oncometabolite which is commonly detected using J-difference editing. Goal(s): Here, we determined the optimal echo time for J-difference editing of 2HG at 3T. Approach: This was done by evaluating the echo time dependence of the 2HG-edited signal using simulations and in vivo experiments. We also quantified the T2 relaxation of 2HG as well as the co-edited glutamate and glutamine signalsResults: A TE of 90 ms was found to produce the highest signal, however, a TE of 70 ms was found to provide the best separation between 2HG and Glx in poor shimming conditions. Impact: This optimized J-difference edited sequence could improve MRS measurements of 2HG. This would take MRS one step closer towards clinical applicability which could aid in the diagnosis and treatment monitoring of glioma patients.
Why have ZTE or bSSFP when you can have both?
Authors: Wood Tobias , Ramachandran Shreya
Published: November 2024

Motivation: Zero Echo-Time MRI has numerous advantages over conventional pulse sequences but also several drawbacks including inefficient k-space sampling and limited PD/T1 contrasts. Goal(s): Improving the efficiency, SNR and contrasts available with ZTE. Approach: Utilising a 3D rosette trajectory to combine the best aspects of the ZTE and bSSFP sequences. Results: Preliminary data indicating the feasibility of the bSSFP ZTE sequence and highlighting limits imposed by current MR hardware. Impact: Highly efficient sequences enable more useable data to be acquired in a single scan. We present a combined bSSFP ZTE sequence that pushes efficiency to the limits of typical MR hardware.
The individuality of human brains when performing tasks
Authors: Huang Jie
Published: November 2024

Motivation: It is imperative to study individual brain functioning when performing tasks. Goal(s): This study aims to develop a novel method to investigate the individuality of human brain functions. Approach: The temporal correlation of a task-evoked activity with the time signal of every point in the brain quantifies the whole brain’s functional co-activity (FC). The spatial correlation of the FC maps of two task trials over the entire brain quantifies the degree of their co-activity, which measures the variation of brain activity when performing these two tasks. Results: The measured trial-to-trial variation of the whole brain’s activity quantified individual brain functioning when performing tasks. Impact: This study presents a novel method to investigate individual brain functioning when performing tasks. The quantified relationship of the whole brain activity with each performed task trial may characterizes the neural bases responsible for individual behavioral and clinical traits.
Voxel-wise DCE-MRI model selection impacts estimates of blood-brain barrier leakage in stroke
Authors: Jones Olivia , Dickie Ben , Parry-Jones Adrian , Higgins David , Haroon Hamied , Al-Bachari Sarah , Emsley Hedley , Parkes Laura
Published: November 2024

Motivation: Different models of DCE-MRI tracer leakage may fit better in different brain regions in cerebrovascular disease and could provide additional insight into BBB function. Goal(s): Demonstrate the utility of voxel-wise DCE-MRI model selection in stroke. Approach: Fit the Extended Tofts, Patlak, and Intravascular models of DCE-MRI tracer leakage to data from controls, ischaemic stroke, and intracerebral haemorrhage patients on a voxel-wise basis, and select the best-fitting model for each voxel using the Akaike Information Criterion. Results: Different models are preferred in different tissue types and disease groups. Model selection increases inter-patient variance of Ktrans compared to Patlak alone. Impact: The Patlak model may not be the most appropriate model for DCE-MRI measurements of blood-brain barrier leakage in ischaemic stroke. Best-fitting model maps could help delineate the extent of “leaky” vs “non leaky” regions based on nested model assumptions.
Fourier-based arterial spin labeling (ASL) data analysis robust against abrupt and periodic artifacts
Authors: Hwang Seon-Ha , Park Sung-Hong
Published: November 2024

Motivation: ASL data has distinct feature in Fourier domain, potentially enabling development of Fourier-based ASL data analysis. Goal(s): To introduce a Fourier-based method to analyze ASL data including fMRI data and verify the robustness to abrupt and periodic artifacts. Approach: Contribution of the abrupt artifacts in the perfusion frequency component was estimated and eliminated to recover the perfusion signal. For the robustness to the periodic artifacts, weighted regression was applied for correlation calculation in the ASL fMRI analysis. Results: The Fourier-based ASL analysis yielded higher SNR in abrupt artifacts and more robust fMRI maps with periodic artifacts. Impact: The proposed Fourier-based ASL analysis method is robust to various artifacts, yielding higher SNR and more robust fMRI maps. The study demonstrated for the first time that ASL perfusion fMRI data can be analyzed in Fourier domain, providing new perspectives.
Super Resolution Using Sparse Sampling at Portable Ultra-Low Field MR
Authors: Donnay Corinne , Okar Serhat , Poorman Megan , Reich Daniel , Nair Govind
Published: November 2024

Motivation: Ultra-low field (ULF) MRI is cost-effective and portable but has limited signal-to-noise ratio (SNR) and lower resolution. Goal(s): To develop a Fourier-based Super Resolution (FouSR) approach to enhance the resolution of ULF MRI images by combining spatial frequencies from two orthogonal ULF images. Approach: In a standard phantom and a cohort of 10 participants with multiple sclerosis (MS) we compared FouSR to ULF coronal and axial images and their average. Results: FouSR demonstrated improved image sharpness and lesion delineation without sacrificing SNR. Visual assessments of in-vivo data by an experienced MS neurologist supported the superior image quality of FouSR. Impact: The presented Fourier-based Super Resolution (FouSR) approach improves image resolution of ultra-low field MRI, providing sharper images for radiological assessment.
POSE: POSition Encoding for accelerated MRI
Authors: Jang Albert , Liu Fang
Published: November 2024

Motivation: Quantitative MRI requires multiple acquisitions to sufficiently characterize a biophysical-model of interest, resulting in long scan times. Goal(s): Propose a new general strategy for accelerating MRI using subvoxel-shifting as a means of encoding. Approach: POSition Encoding (POSE) applies unique subvoxel-shifts along the acquisition parameter dimension, which is combined with a biophysical-model to generate accelerated and enhanced resolution biophysical-parameter maps. Using T1 quantification as an application, POSE was validated both numerically and experimentally. Results: Results show that POSE 1) generates quantitative maps that agree well with the reference method, 2) has robust noise performance and 3) is applicable to any biophysical-model of interest. Impact: POSE combines subvoxel-scale spatial encoding with biophysical-models to achieve enhanced resolution with acceleration. Its ease of implementation, robust noise performance and versatility makes it an attractive framework applicable to any quantitative biophysical-model of interest.
Ultra-fast radial encoding with oscillating gradients: Potential of a high performance ultrasound gradient insert
Authors: Liu Shuai , Wehkamp Niklas , Ilbey Serhat , Bock Michael , Özen Ali
Published: November 2024

Motivation: Radial sampling offers motion-robust, high bandwidth MRI with incoherent undersampling, but suffers from inefficient k-space sampling. 3D radial acquisitions can be accelerated using non-conventional gradient trajectories. Goal(s): To investigate the potential improvements in point spread function and acquisition time for radial encoding using oscillating gradients. Approach: Radial spokes are modified to a conical helix trajectory using external sinusoidal gradients to increase sampling efficiency. Acceleration potential and PSF were calculated using numerical simulations. Proof-of-principle phantom measurements were performed at 3T using a field camera. Results: Radial sampling with oscillating gradients improves PSF and allows for an up to 5-fold acceleration. Impact: This study demonstrates first high-frequency conical helix spokes in 3D using high frequency oscillating gradients. Using external ultrasound (>20kHz) gradients, the proposed trajectory can significantly improve the PSF for both low-resolution and high-resolution protocols while providing extremely high acceleration factors.