bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing spoiling characteristics for gas-phase hyperpolarized 129Xe transmit RF calibration
Authors: Costelle Anna , Driehuys Bastiaan , Mugler John
Published: November 2024

Motivation: Manufacturer-supplied transmitter calibrations are unsuitable for 129Xe MRI due to the transient nature of its magnetization, but existing 129Xe calibration protocols exhibit incomplete spoiling that adversely affects accuracy in flip angle measurements. Goal(s): We sought to develop a new spoiling-gradient configuration for 129Xe MRI transmit calibration that corrects the incomplete spoiling and improves accuracy. Approach: Spoiling configurations were simulated, tested, and optimized in a water phantom. The optimal configuration was tested in subjects who underwent 129Xe MRI with both calibration schemes. Results: A configuration that increases spoiling-gradient moment with each FID corrected the incomplete spoiling and improved the accuracy of flip angle measurements. Impact: Implementing a 129Xe MRI transmit calibration that increases spoiling-gradient moment with each FID acquisition improves accuracy in flip angle calculations, thereby ensuring consistently optimal image quality for all subjects and advancing the clinical utility of 129Xe MRI.
Compressed sensing reconstruction for high-SNR, rapid dissolved 129Xe gas exchange MRI
Authors: Pilgrim-Morris Jemima , Collier Guilhem , Munro Ryan , Marshall Helen , Norquay Graham , Stewart Neil , Wild Jim
Published: November 2024

Motivation: 3D hyperpolarized 129Xe gas exchange imaging is limited by low SNR and long breath-holds, which is problematic for patients with dyspnea and/or low gas transfer. Compressed sensing (CS) reconstruction can accelerate 129Xe MRI whilst improving SNR. Goal(s): To assess whether gas exchange ratio maps are quantitatively preserved with CS dissolved 129Xe imaging and investigate the feasibility of reduced-cost natural abundance (NA) CS dissolved 129Xe imaging. Approach: CS-reconstructed gas exchange ratios were evaluated in healthy volunteers and COPD patients and prospectively with NA 129Xe. Results: CS increased image SNR, allowed 3-fold acquisition acceleration and maintained ratio map fidelity, even with NA 129Xe. Impact: Compressed sensing reconstruction of dissolved 129Xe spectroscopic imaging improved image quality even with decreased scan time, whilst preserving key gas exchange metrics. This will benefit patients with breathlessness and/or low gas transfer and enables natural abundance dissolved 129Xe imaging.
Energetic Metabolism during Preclinical Migraine Measured by 31P Spectroscopy at 21.1 T
Authors: Richter Dayna , Grant Samuel
Published: November 2024

Motivation: Migraine is a disorder of neuronal hyperexcitability, but previous work has not been able to capture energetic processes non-invasively during active central sensitization, only after or between migraine attacks. Goal(s): This preclinical study evaluates whole brain energetic metabolism and remodeling during a nitroglycerin-induced migraine attack. Approach: 31P spectroscopy using ISIS was used to measure phosphocreatine and ATP levels at baseline and then over a 3-hour period post-NTG administration. Results: Most notable is the increase in phosphocreatine compared to baseline and controls, as well as an increase in ATP compared to baseline. Both indicate energetic remodeling during central sensitization prior to migraine pain onset. Impact: Increased phosphocreatine and ATP over the entire brain demonstate significant energetic fluxes during cerebral central sensitization and prior to nociception. This energetic remodeling informs understanding of fundamental migraine pathophysiology and its timing, potentially impacting the administration of potential clinical interventions.
Deuterium metabolic imaging of early response to targeted therapy in pediatric brain tumors.
Authors: Taglang Celine , Batsios Georgios , Gillespie Anne-Marie , Mueller Sabine , Viswanath Pavithra
Published: November 2024

Motivation: Diffuse midline gliomas (DMGs) are devastating pediatric brain tumors. Although MRI is the mainstay for DMG imaging, it does not reliably report on response to therapy. Goal(s): The goal of this study was to assess the utility of deuterium metabolic imaging for DMGs. Approach: To this end, we interrogated [6,6’-2H]-glucose metabolism in patient-derived and syngeneic models. Results: [6,6’-2H]-glucose enables non-invasive visualization of the metabolically active tumor lesion in mice bearing intracranial DMGs. Importantly, [6,6’-2H]-glucose provides an early readout of response to targeted therapy in vivo. Collectively, our studies highlight the potential of [6,6’-2H]-glucose for imaging tumor burden and response to therapy in DMGs. Impact: Diffuse midline gliomas are deadly childhood brain tumors. Using clinically relevant patient-derived and murine tumor models, we show that deuterium metabolic imaging using [6,6’-2H]-glucose enables non-invasive assessment of tumor burden and early response to therapy in diffuse midline gliomas.
GABA+ and Glutamate Metabolites Correlates with Clinical Semeiology of Lateralization in Unilateral Temporal Lobe Epilepsy: MEGA-PRESS Study.
Authors: Kumar Manoj , Pradhan Nikhilesh , Mangalore Sandhya , Bairwa Pawan , K Raghvendra , Deelchand Dinesh , LG Vishwanathan , Asranna Ajay , RC Mundlamuri , PV Prathyusha , Sinha Sanjib
Published: November 2024

Motivation: TLE is a common epileptic syndrome. Potential dysregulation in GABAergic and glutamatergic mechanisms in epilepsy include neuronal, glial, and/or neuronal-glial interaction dysfunction, leading to increased seizure risks. Goal(s): The study aimed to explore the utility of MEGA-PRESS MRS in patients with drug-resistant temporal lobe epilepsy for seizure lateralization. Approach: In-vivo MRS to assess GABA and Glu levels and video-EEG in drug-resistant unilateral TLE patients for seizure localization. Results: Concordance between neurometabolites with video-EEG for lateralization demonstrates that the correct classification percentage for GABA was 86.7%, indicating an 86.7% chance that GABA will be able to lateralize the unaffected side as detected by VEEG. Impact: Clinical utility of MEGA-PRES as a presurgical tool for assessing in-vivo neurometabolic profiles and adding knowledge of the role of GABA and Glu in epilepsy and its interplay
Study of brain network alternations in sleep-related hypermotor epilepsy by resting-state functional magnetic resonance imaging
Authors: Pu Huaxia , Pu Huaxia , Wu Xintong , Wang Liping , Tan Qiaoyue , Wang Weina , Wan Xinyue , Su Xiaorui , Zhang Simin , Yue Qiang , Gong Qiyong
Published: November 2024

Motivation: To investigate the topological properties of brain functional connectomes in patients with sleep-related hypermotor epilepsy (SHE). Goal(s): Little is known about the topological organization changes of brain functional networks in SHE patients. Approach: 57 SHE patients and 54 healthy controls underwent resting-state functional MRI examination. Topological properties of brain networks were identified using graph-based theoretical analysis. Results: Compared to controls, SHE patients showed longer characteristic path length (Lp) and lower global efficiency (Eglob), decreased nodal centralities in several regions, and connectivity aberrations. Lp and normalized Lp had positive correlations while Eglob and nodal centralities of thalamus had negative correlations with epilepsy duration. Impact: The aberrant topological properties in brain functional networks of SHE may provide insights into the pathophysiology of epileptogenesis. The identification and characterization of network changes may contribute to clinical treatment through the disruption or inhibition of these epileptogenic networks.
A potential mechanism of neurological impairment in children with infantile spasm:a structure analysis employing voxel-based morphometry
Authors: wang xiaoyu , Huang Yuchun , Deng Kan , Mo Tong , Qi Xinxin , Zeng Hongwu
Published: November 2024

Motivation: Whether there is micro-structural alteration in the temporal lobe of Infantile epileptic spasms syndrome (IESS) patients is yet to be clarified, of which resulting in severe language function impairment. Goal(s): To explore the potential mechanism of neurological impairment in children with IESS. Approach: We conducted a study with BSID-II for clinical evaluation, meanwhile voxel-based morphometry (VBM) for MRI data analysis. Results: In IESS group, the most significant volume loss of gray matter in right fusiform (Broadman area 21) and middle temporal gyrus (Wernicke's area) were key node for voice recognition, language processing, semantic retrieval, memory, and understanding network. Impact: The findings of this study light up an anatomical basis for language impairment in children with IESS.
Intratumor and peritumor MRI radiomics features of rectal cancer can predict overall survival after neoadjuvant therapy
Authors: Guo Xiaofang , He Yaoyao , Yuan Zilong , Nie Tingting , Liu Yulin , Xu Haibo
Published: November 2024

Motivation: Use MR radiomics features as a potential factor for predicting overall survival (OS) after neoadjuvant therap in rectal cancer. Goal(s): To explore the ability of the intratumoral and peritumoral radiomics features to predict the OS. Approach: A nomogram that combines clinical features, intratumor and peritumor radiomics features from T2WI using Machine Learning to predict OS was developed, validated using the Kaplan-Meier survival curve. Results: There was a significant statistical difference in the label scores between the high-risk and low-risk groups divided by median survival time as the cutoff value. The C-index of the training and test cohort was 0.798, 0.772 respectively. Impact: The radiomics model of peritumor radiomics features as the intratumor model can predict the OS in rectal cancer with neoadjuvant therapy. Combined with clinical features and the radiomics model of intratumor radiomics features, high accuracy can be obtained.
An MRI-Based Radiomics Model for Preoperative Prediction of Microvascular Invasion and Overall Survival in Intrahepatic Cholangiocarcinoma
Authors: Miao Gengyun , Qian Xianling , Zhang Yunfei , Yang Chun , Zeng Mengsu
Published: November 2024

Motivation: Microvascular invasion (MVI) is a significant prognostic factor in intrahepatic cholangiocarcinoma (ICC). Goal(s): This study aimed to develop an MR radiomics-based model for preoperative MVI status stratification and overall survival prediction. Approach: Univariate and multivariate logistic regression identified independent clinical and imaging predictors. The radiomic model, utilizing robust features and a logistic regression classifier with the least absolute shrinkage and selection operator algorithm, was integrated into the imaging-radiomics (IR) model. Results: The IR model demonstrated strong performance (AUCtraining=0.890, AUCvalidation=0.885, AUCtest=0.815), confirmed by calibration and decision curves, and its predicted survival closely matched histological methods. Impact: The MRI-based radiomics models for preoperative MVI status and OS prediction holds the promise of enabling physicians to tailor medical regimens in ICC patients, optimizing their individual benefit.
Investigation of ComBat Harmonization on Radiomic and Deep Features from Multi-Center Clinical Abdominal MRI Data
Authors: Dillman Jonathan , Jia Wei , Li Hailong , Ali Redha , Shanbhogue Krishna , Masch William , Aslam Anum , Harris David , Reeder Scott , He Lili
Published: November 2024

Motivation: Multi-center studies often suffer from non-biological variations due to different MRI scanners. This can adversely affect the comparability of MRI radiomic features and deep features. Goal(s): This multi-center study aims to investigate the effectiveness of ComBat harmonization on radiomic and deep features from abdominal MRI data. Approach: We retrieved 3,857 clinical T2-weighted MRI examinations of adult patients from three institutions. The ANOVA test and Cohen’s F score were applied as evaluation metrics. Results: An average of 78.7% of radiomic features, and 74.9% of deep features had significant distribution differences. After ComBat harmonization, none of radiomic and deep features had significant difference. Impact: This multi-center study showed that ComBat can effectively remove non-biological variations of radiomic and deep features from abdominal MRI studies acquired from different MRI scanners and institutions. Future multi-center studies should consider ComBat harmonization to improve data comparability.
Robust generation of tract-wise myelination measurements from infant T1- and T2-weighted MRI using synth based deep learning methods
Authors: Tregidgo Henry , Bradford Layla , Williams Simone , Bourke Niall , Zieff Michal , Nabi Zayaan Goolam , Mazubane Thandeka , Wijeratne Peter , Zöllei Lilla , Iglesias Juan Eugenio , Williams Steven , Jones Derek , Donald Kirsty , Alexander Daniel
Published: November 2024

Motivation: While T1/T2-weighted ratio maps are important for the study of myelination, existing reconstruction tools can fail in infants and present difficulty to automated segmentation. Goal(s): To provide a pipeline for obtaining accurate regional myelination measures of whole brain regions and white matter tracts. Approach: We adapted existing T1/T2-weighted ratio pipelines to incorporate deep learning methods for segmentation and registration as well as a high-quality tract atlas. Results: Our pipeline showed reduced errors and improved differentiation between 3- and 6-month-old infants from a South African longitudinal birth cohort study. Impact: The improved T1/T2-weighted ratio contrast and detailed segmentations provided by our pipeline will enable study of specific myelination patterns during neurodevelopment, especially in populations exposed to risk factors for altered white matter maturation.
Dynamic quantitative susceptibility mapping to measure cardiac pulsation and respiration induced endogenous brain signal changes
Authors: Sonderer Christa , Chen Nan-kuei , Wen Qiuting
Published: November 2024

Motivation: The contribution of physiologically induced dynamic magnetic susceptibility within the brain to the blood oxygen level dependent (BOLD) signal used for functional imaging has never been quantified. Goal(s): Our goal was to measure the brain’s dynamic magnetic susceptibility signal as a function of the cardiac and respiratory cycles using quantitative susceptibility mapping (QSM). Approach: We developed and evaluated an image processing framework to generate dynamic susceptibility maps over the course of cardiac pulsation and respiration. Results: We demonstrated that QSM is sensitive to physiologically induced susceptibility changes and that our framework can be used to measure these dynamics. Impact: The influence of physiologically induced dynamic magnetic susceptibility on BOLD signal could impact the derivation/interpretation of BOLD-based functional connectivity. Significant susceptibility changes could indicate a need to modify existing functional mapping approaches whereas the reverse would validate current techniques.
Evaluation of liver function using Gd-EOB-DTPA-enhanced MRI by B1-corrected VFA T1 mapping method
Authors: Tan Yingying , Long Liling , Zhang Huiting
Published: November 2024

Motivation: There is a lack of suitable tools for monitoring liver function to determine the optimal treatment strategy for patients. Goal(s): To evaluate the value of B1-corrected VFA T1 mapping in predicting liver function. Approach: T1 relaxation time at corresponding time-points in B1-corrected VFA T1 mapping were measured. We analyzed the correlation of T1 value with indocyanine green retention rate at 15min (ICG-R15) and conducted Receiver operating characteristic (ROC) to evaluate the albumin-bilirubin (ALBI) grade classification efficiency by T1 mapping parameters. Results: T1-10min, T1-HBP and △T1% showed moderate correlation with ICG-R15. T1-5min had the best diagnostic efficacy in differentiating ALBI 1 and ALBI 2. Impact: This study explored that T1 value of Gd-EOB-DTPA-enhanced MRI by B1-corrected VFA method can be used as noninvasive imaging indicators for estimation of liver function.
Layer ReHo: Tool for characterizing mesoscale functional structure across layers and columns
Authors: Akin Burak , Klein Richard , Koiso Kenshu , Yu Yinghua , Yang JiaJia , Huber Renzo , Bandettini Peter
Published: November 2024

Motivation: High resolution fMRI is an emerging field, analysis pipelines are still under development. Local and short distanced time course similarities also named as Layer dependent regional homogeneity, can give us insights to map laminar dependent signal differences. Goal(s): Using a simple metric to color code the depth dependent cortical activity. Approach: Using mesoscale functional structure to predict and understand, time locked activity patterns in cortical ribbon without having necessity of specific model or predefined ROIResults: Layer dependent regional homogeneity predicts local activity patterns, also can be used as a similarity matrix to rank different runs which potentially contributes to similar layer patterns. Impact: This work can potentially be a publicly available analysis tool to observe and quality check, can also quantify laminar separability of the acquired depth dependent high resolution fMRI data.
Laminar fMRI of the human hippocampus: Accounting for physiological fluctuations and vasculature
Authors: Pfaffenrot Viktor , Bouyeure Antoine , Axmaher Nikolai , Norris David
Published: November 2024

Motivation: Laminar fMRI of the human hippocampus is challenging and not easy to interpret due to differences in the direction of venous drainage. Goal(s): Acquire robust and reproducible single-subject laminar fMRI responses using GRE-BOLD. Approach: An autobiographical memory task was used at 7 T to elicit hippocampal activation in two subjects each scanned twice. We quantified subregion-specific cortical depth-dependent activation after accounting for physiological signal fluctuations. Results: We show that laminar profiles differ between subjects but are to a high degree reproducible within subjects and that these profiles were consistent with previous findings at lower spatial resolution. Impact: Our results show that for laminar fMRI of deeper brain areas, physiological fluctuations need to be corrected to obtain reproducible data. The consistent difference between subjects indicate that subject-specific vasculature needs to be considered.
Functional line-scanning of cortical layers at 3T and 7T
Authors: Liu Guoxiang , Ueguchi Takashi , Ogawa Seiji
Published: November 2024

Motivation: Recently, line-scanning fMRI has been used to map laminar BOLD response, because it can enhance spatial resolution to sub-millimetre with sub-second TR. Some animal studies at high field scanner have been reported. Goal(s): Line-scan scheme that can keep thin line profiles and provide multi T2* relaxed conditions for BOLD signal measuring is requested for layer fMRI. Approach: We developed a multi-shot spin echo EPI based line-scan scheme with a readout train after spin echo time. Results: Our 1D line-scanning finger tapping/grabbing fMRI results show the capability of this sequence to study differences in cortical layers in the human cortex. Impact: The proposed line-scanning sequence can detect different BOLD response at different layers at M1/S1 in high resolution fMRI studies at 3T and 7T
Human Layer-specific VASO fMRI at 5.0T Whole-body MRI Scanner: A Preliminary Study
Authors: Zhang Zhilin , Li Ye , Wei Zidong , Zhou Yihang , Liang Dong , Wu Jinglong , Wang Haifeng
Published: November 2024

Motivation: This study seeks to address the challenge of human layer-specific fMRI at 5.0T whole-body MRI scanner. Goal(s): Develop Layer-specific VASO fMRI based on the slice-selective slab-inversion vascular space occupancy (SS-SI VASO) pulse sequence at 5.0T scanner. Approach: The SS-SI VASO pulse sequence with GOIA RF pulse at 5.0T scanner has been developed with the five processing steps, including noise reduction with distribution corrected (NORDIC), motion correction, BOLD correction and contrast combination, quality measures, and functional activity. Results: The preliminary results have shown that the in vivo experiment of finger tapping for VASO fMRI at 5.0T scanner is feasible as similar as BOLD fMRI. Impact: The preliminary experiments provided by layer-specific VASO fMRI at 5.0T scanner can help scientists and doctors in accurately identifying and diagnosing primary motor cortex or other brain applications.
Aberrant functional connectivity of multiple networks in first-episode adolescence-onset major depressive disorder
Authors: yang chunyu , Zhou Zilin , Bao Weijie , Zhong Ruihan , Qiu Lihua , Tang Mengyue , Gao Yingxue , Wang Yidan , Zhou Huan , Hu Xinyue , Zhang Lianqing , Huang Xiaoqi
Published: November 2024

Motivation: The underlying mechanisms in adolescent-onset major depression disorder (AO-MDD) remains unclear with only few studies in small sample size. Goal(s): To investigate the alteration of functional connectivity (FC) in multiple networks in AO-MDD patients. Approach: Seed-based analysis was conducted to detect the FC between AO-MDD group and healthy controls (HCs) at the regional and subregional level. Results: Hypoconnectivity in AO-MDD was discovered in seeds including insula, amygdala, hippocampus, and their subregions which belong to salience network and affective network. The FC of the right insula and the left hippocampus correlated with the age of onset. Impact: Our findings provided a comprehensive description of the altered connectivity in multiple networks at regional and subregional levels in AO-MDD pathogenesis. We demonstrated how age of onset contributes to AO-MDD symptomatology.
Frequency-Domain Machine Learning Estimation of Maximum BOLD Modulation and Grey Matter Oxygen Consumption with Resting-State BOLD-ASL fMRI
Authors: Chiarelli Antonio , Germuska Michael , Caligiuri Maria , Patitucci Eleonora , Caporale Alessandra , Biondetti Emma , Di Censo Davide , Chandler Hannah , Murphy Kevin , Wise Richard
Published: November 2024

Motivation: Calibrated BOLD-arterial spin labelling (ASL) fMRI exploits isometabolic hypercapnic changes of brain physiology to map grey matter maximum BOLD modulation (M) and, through biophysical modelling, estimate the oxygen extraction fraction and the cerebral metabolic rate of oxygen. However, this approach requires a CO2 gas-challenge or breath-holding, limiting its clinical application. Goal(s): It would be ideal to estimate M from low SNR, non-isometabolic resting-state (RS) BOLD-ASL fluctuations. Approach: We investigate the ability of a frequency-domain, data-driven, neural network approach to estimate the physiological parameters of interest from RS data in comparison to a breath-hold approach. Results: The proposed approach can map the desired parameters. Impact: The ability to map oxygen consumption in the grey matter through resting state data using a calibrated fMRI framework would allow a simple implementation of such an approach in research settings paving the way to its utilization in clinical practice.
Comparison of the spatial distribution of BOLD Regional Homogeneity (ReHo) and Cerebral Blood Flow at rest
Authors: Di Censo Davide , Chiarelli Antonio , Patitucci Eleonora , Germuska Michael , Censi Stefano , Graziano Francesca , Biondetti Emma , Caporale Alessandra , Tomassini Valentina , Wise Richard
Published: November 2024

Motivation: Regional Homogeneity (ReHO) of BOLD signal is a potential marker of brain activity at rest. CBF is coupled to metabolism in the human brain and it can be used to investigate the physiological significance of ReHo. Goal(s): We aimed to assess the spatial correlation between ReHo and ASL-derived CBF and its temporal stability. Approach: Twenty subjects underwent 28 minutes of simultaneously acquired BOLD-ASL resting-state fMRI. CBF and ReHo spatial associations at different times were estimated and compared. Results: We found a modest but stable and significant spatial correlation between CBF and ReHo. Impact: This study could be significant for diagnosis and treatment of neurological disorders. If ReHo is demonstrated to be a reliable marker of local brain metabolism, it could be used to develop new fMRI methods for detecting and monitoring brain disorders.
Retrospective Automatic Motion Detection in fMRI using k-space information
Authors: Kim Dong Wook , Jung KyuJin , Cui Chuanjiang , Lee SooHyoung , Seo SeungYeon , Kim Dong-hyun
Published: November 2024

Motivation: Handling subject motion in fMRI is an important issue. Thus, it's ideal to correct motion as thoroughly as possible during data preprocessing. Goal(s): We aim to develop an algorithm that accurately detects precise motion corrupted measurements to efficiently correct motion. Approach: Motion signal was obtained from the k-space data by calculating average squared difference between first measurement and successive measurements . Equation of threshold value to verify presence of motion was formulated. Lastly, the outliers in motion signal were detected using WLS(weighted least square) optimization framework. Results: The proposed method successfully detects precise motion corrupted measurements automatically. Impact: The proposed method can facilitate precise fMRI analysis by detecting motion corrupted measurements in advance to data preprocessing procedure and applying suitable corrections, which enables us to input less motion contaminated data from the early stages of fMRI data preprocessing.
A functional magnetic resonance imaging (fMRI) study of adolescents solving complex mathematical operations
Authors: Istomina Asya , Faber Andrei , Ublinskiy Maxim , Manzhurtsev Andrei , Arsalidou Marie
Published: November 2024

Motivation: Mathematical processes are widely studied using neuroimaging techniques. Goal(s): However limited knowledge exists on neurofunctional correlates of distinct mathematical operations, in adolescent samples, as the majority of studies are with adults or children. Approach: We examine for the first time, using fMRI, brain activity associated with complex addition, subtraction, multiplication, and division in adolescents. Results: Our study demonstrates the engagement of fronto-parietal, cingulo-operclum networks, and the cerebellum in mathematical operations. Further, we shed light on brain regions not frequently discussed in models of mathematical cognition, including the left temporal gyrus and bilateral supplementary motor area (SMA), specific to complex subtraction and division. Impact: Results of the study add new knowledge on a modeling mathematical processes in adolescents. Coordinates in stereotaxic space can serve as a benchmark for future research with neurodevelopmental disorders as well as for individuals exhibiting exceptional mathematical proficiency.
Dynamics of brain neurotransmitters levels in response to a short visual stimulus measured using functional MRS at 3T
Authors: Iakovlev Aleksei , Ublinskiy Maxim , Manzhurtsev Andrei , Vanin Anatoly , Akhadov Tolib
Published: November 2024

Motivation: Current assumptions propose that rapid fluctuations in Glu levels are associated with its release from vesicles in response to an event-related stimulus. Therefore, there should be rapid changes in GABA and Glu in response to a short stimulus that will show local stimulus-induced inhibition and excitation. Goal(s): To quantify GABA and Glu levels following a brief visual stimulus lasting three seconds. Approach: Single voxel 1H-MRS was used to measure GABA (MEGA-PRESS) and Glx (PRESS) levels. Flickering checkerboard (3s) was used for stimulation. Results: Both neurotransmitter levels showed increase in first seconds after stimulus presentation and following decrease to a basic level. Impact: This study tests hypothesis regarding rapid neurotransmitter level changes induced by vesicular release in response to short stimuli. The findings from this research have the potential to offer novel insights and methodologies for investigating neural processes.
Accelerated High-Resolution 3D Gradient Echo with DL-Based Reconstruction Improves T2* Mapping for Oxygenation-Sensitive MRI
Authors: Saks Elisa , Hoffmann Gabriel , Eichhorn Hannah , Weiss Kilian , Kaczmarz Stephan , Zimmer Claus , Preibisch Christine
Published: November 2024

Motivation: Standard low-resolution 2D-GRE acquisition for T2* mapping in mqBOLD MRI may suffer from long scan durations and insufficient quantification accuracy. Goal(s): Improving quantification accuracy by switching from 2D to high-resolution 3D multi-echo GRE while simultaneously reducing scan duration by applying compressed sensing (CS) acceleration with deep-learning-based reconstruction. Approach: T2* maps from low-resolution 2D-GRE and high-resolution 3D-GRE with different acceleration factors were compared in 11 healthy volunteers based on visual inspection and VOI-analyses. Results: 3D-GRE yields high-resolution parameter maps with improved T2* values for GM/WM in less than half the scan duration compared to standard 2D-GRE when using CS acceleration with DL-based reconstruction. Impact: High-resolution 3D-GRE with compressed sensing acceleration and deep-learning-based reconstruction was compared to standard 2D-GRE visually and quantitatively. 3D-GRE enables clinically feasible scan durations with improved and reliable T2* mapping, which may add to the clinical applicability of oxygenation-sensitive mqBOLD MRI.
Simulations of systematic error in a new quantitative BOLD method incorporating an independent measure of deoxygenated blood volume
Authors: Stone Alan , Blockley Nicholas
Published: November 2024

Motivation: To investigate sources of error in a new quantitative BOLD technique incorporating an independent measure of deoxygenated blood volume. Goal(s): Simulate the effect of systematic error and system noise on estimates of oxygen extraction fraction. Approach: Monte Carlo simulations of the random walk of protons around deoxygenated blood vessels modelled as infinite cylinders were performed using a standard approach. Results: These simulations show that introducing an independent measure of DBV into the qBOLD framework provides improved estimates of oxygen extraction fraction. Impact: This improved technique for mapping oxygen extraction has wide applications in the study of neurological disorders including stroke, dementia and cancer.
Reducing the Impact of Anesthesia on Glucosamine Uptake in the Mouse Brain
Authors: Rivlin Michal , Navon Gil
Published: November 2024

Motivation: Anesthetic drugs vary in their capacity to interfere with homeostatic mechanisms responsible for glucose metabolism in the brain, thus pose a possible constraint in the study design. Goal(s): To evaluate the preferred anesthesia protocol for preclinical imaging of glucosamine metabolism in healthy mice brains. Approach: The effects of different anesthetics procedures on brain glucosamine metabolism were investigated using the CEST MRI method. Results: Mice injected with glucosamine and anesthetized with 1.5% isoflurane exhibited a low and insignificant increase in MTRasym signals in the cortex, whereas mice given 0.8% isoflurane combined with midazolam demonstrated a significant increase in MTRasym signals in the cortex. Impact: Combining low levels of isoflurane with midazolam anesthesia, enables increased glucosamine CEST MRI signal, indicating enhanced glucosamine uptake through the BBB. These findings offer valuable insights for optimizing glucosamine metabolic imaging, which can be extended to other glucose analogs.
Combining T1 and T2* contrast in dynamic Oxygen-Enhanced MRI (dOE-MRI) to assess Tumour Hypoxia.
Authors: Hofmann Annika , Baker Jennifer , Moosvi Firas , Reinsberg Stefan
Published: November 2024

Motivation: There is a need for non-invasive imaging markers for tumor oxygenation to develop hypoxia-targeted treatment. Goal(s): Extend dynamic oxygen-enhanced MRI to incorporate T1 and T2* contrast, enhancing our ability to assess tumor tissue oxygenation more effectively. Approach: Independent Component Analysis maps were used to analyze the signal intensity change in T1 and T2* weighted images for pancreatic PDX tumour models in 26 mice, scanned at 7T. Results: The results showed a significant correlation between ΔT1 and ΔT2* in two PDX tumor models, but not in another model. This discrepancy is attributed to differences in tissue oxygenation inherent to the PDX tumor models studied. Impact: This research demonstrates the potential of dynamic oxygen-enhanced MRI to differentiate tissue oxygenation in pancreatic PDX tumor models. It highlights the complexity of the relationship between T1 and T2* signal changes induced by a cyclic gas breathing challenge.
Accuracy, repeatability, and sensitivity of breath-hold calibrated fMRI for the mapping of absolute CMRO2
Authors: Driver Ian , Chiarelli Antonio , Wise Richard , Germuska Michael
Published: November 2024

Motivation: Gas-calibrated fMRI provides a sensitive measurement of cerebral oxygen consumption, but its applicability is limited to young, healthy participants who can tolerate the gas challenges. Goal(s): Our goal was to establish the feasibility of breath-hold calibrated fMRI (bhc-fMRI) to replace gas challenges. Approach: We compared bhc-fMRI to a global oxygen extraction fraction (OEF) measurement, measured within session repeatability and tested the sensitivity of the method to a visual stimulus. Results: We found similar agreement to global OEF measurements as for gas-calibrated fMRI and moderate within session repeatability. Robust responses to continuous visual stimulation of CBF/CMRO2/OEF (+15%/+11%/-3%) demonstrate good sensitivity of the bhc-fMRI method. Impact: We establish breath-hold calibrated fMRI as a viable alternative to gas-calibrated fMRI for mapping cerebral oxygen consumption. Breath-hold calibrated fMRI is simple to implement and is tolerable for ageing cohorts and patients with neurodegenerative pathologies.
MR Molecular Imaging of Pancreatic Ductal Adenocarcinoma during a Therapeutic Vaccine Regimen
Authors: Laney Victoria , Hampson Emma , Wang Lily , Lu Zheng-Rong
Published: November 2024

Motivation: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive form of cancer with a low survival rate. Immunotherapies have been able to overcome some of the barriers of traditional therapy with PDAC, resulting in increased survival. However, immunotherapy results in responsive and non-responsive tumors. Goal(s): This study aims to use MR molecular imaging with a contrast agent that's specific to the tumor microenvironment to determine responders and monitor therapy. Approach: MR molecular imaging T1w images at discrete timepoints with contrast injection and during therapy. Results: CNR changes were detected using MR molecular imaging on mice bearing PDAC tumors during a vaccine regimen. Impact: There is an absence of biomarkers/predictive tools for pancreatic cancer response to immunotherapy. There’s a critical need for therapeutic strategies that improve patient outcomes in tandem with imaging methods that can monitor disease progression and accurately guide clinical decision making.
129Xe MR Spectroscopy reveals Abnormal Gas-exchange in Moderate and Severe Asthma
Authors: Sharma Maksym , Kooner Harkiran , Mozaffaripour Ali , Tcherner Sam , Yamashita Cory , Parraga Grace
Published: November 2024

Motivation: Airways disease in asthma is characterized by airway wall thickening, luminal obstruction and smooth muscle hyper-responsiveness. Abnormal CT pulmonary vascular pruning has also been reported. We wondered if 129Xe MRS could identify functional abnormalities related to the pulmonary vascular tree, via the measurement of gas-exchange across the alveolar-capillary membranes, into the red-blood-cells. Goal(s): Measure and compare 129Xe MRS RBC:membrane in healthy volunteers, and patients with moderate or severe asthma. Approach: 129Xe MRI, MRS and pulmonary function measures were acquired in healthy-volunteers and asthma participants. Results: 129Xe MR RBC:membrane was significantly different in healthy-volunteers, moderate and severe asthma. Impact: To our knowledge, this is the first demonstration of significantly different 129Xe MRS RBC:membrane values in healthy volunteers, and patients with moderate or severe asthma. Abnormal pulmonary gas-exchange may play a role in asthma, regardless of disease-severity.
Mapping Hyperpolarised 129Xe Gas Exchange with CSSR – CSI in a Model of Radiation-Induced Lung Injury
Authors: Taylor Yohn , Loza Luis , Ruppert Kai , Kim Mina , Jimenez-royo Pilar , Parker Geoff
Published: November 2024

Motivation: Regional assessment of functional decline due to radiation-induced lung injury (RILI) remains challengingGoal(s): We aimed to assess the accuracy of the recently introduced kinetic model of xenon exchange (kMXE) by comparison with the established MOXE model using hyperpolarised 129Xe MRIApproach: Employing a RILI rat model, we implemented gas exchange mapping of hyperpolarised 129Xe MRI chemical shift imaging data using 1D compartmental diffusion models. Results: The kMXE results matched the MOXE model well. Both models demonstrated asymmetric outcomes in the RILI cohort, diverging from the homogeneous results in the healthy group. Impact: Using hyperpolarised 129Xe MRI, we evaluated the effectiveness of kMXE and MOXE models and demonstrate their ability to uncover regional functional variations, providing potential biomarkers for assessing the longitudinal progression of radiation-induced lung injury.
The Successful Use of Unenriched Xenon in Dissolved Gas MRI: A Case Report
Authors: Wolfsohn Micah , Anya Natalia , Collier Guilhem , Dashnaw Stephen , Munro Ryan , Norquay Graham , Prince Martin , Rodgers Oliver , Schulte Rolf , Shen Wei , Wild Jim , Zhang Xuzhe , Hughes Emlyn , Barr Robert
Published: November 2024

Motivation: We sought to demonstrate the safety and efficacy of a hyperpolarized gas MRI protocol for assessing the pulmonary physiology of long-COVID. Goal(s): Our goal was to gather preliminary dissolved phase images utilizing unenriched xenon. Approach: Volumes of 300mL and 500mL of unenriched xenon were hyperpolarized using a 180W diode laser at 795nm and administered to two healthy subjects. Scans were obtained using a 3T SIGNATM Premier scanner and a 129Xe Quadrature T/R lung coil. Images were masked using signal-to-noise thresholding on tissue/plasma signal. Results: We found strong red blood cell and tissue/plasma xenon signal in both subjects utilizing 300mL of unenriched xenon. Impact: At present time, successful dissolved xenon imaging has only been described with the use of enriched xenon-129. Our findings suggest that less expensive and more widely available unenriched xenon may be used in dissolved gas MRI.
Quantify sodium transmembrane transport in cells via relaxation exchange spectroscopy
Authors: Yin Yu , Xia Juntao , Chen Yun , Bai Ruiliang , Kong Xueqian
Published: November 2024

Motivation: Transmembrane transport of sodium ions is directly related to the cell functions and metabolisms and could be an indicator of various diseases such as neurodevelopmental disorders, neuropathic pain, etc. There is a lack of non-invasive and clinically-adaptable techniques for quantifying the rate of transmembrane transport of sodium ions. Goal(s): Determine the rate of sodium transmembrane transport using noninvasive nuclear magnetic resonance methods. Approach: 23Na relaxation exchange spectroscopy (REXSY) was applied to the cellular systems for quantitative analysis. Results: The 23Na REXSY method successfully determined the sub-second transmembrane exchange rate of sodium ions in yeast and HeLa cells. Impact: Measuring transmembrane rate of sodium via NMR can assist the pathological studies of diseases related to malfunctions of sodium ion channels and/or sodium metabolism. 23Na REXSY could be coupled to MR imaging to offer novel parameters for clinical diagnosis.
Analysis of Histogram Rescaling on Hyperpolarized 129Xe MRI Ventilation Distribution: A Deep Learning-Based Study of Trachea Segmentation
Authors: Lu Junlan , Du Kunyu , Leewiwatwong Suphachart , Huang Yuh-Chin , Driehuys Bastiaan
Published: November 2024

Motivation: Hyperpolarized 129Xe MRI, pivotal for lung function analysis, faces challenges in standardizing ventilation distribution calculations, particularly regarding image rescaling and major airway inclusion. Goal(s): To develop a deep learning-based method to segment the trachea and assess its impact on the ventilation distribution. Approach: We trained and compared various deep learning models for robust segmentation. Results: In patients with interstitial lung disease, the ratio of 129Xe signal in the trachea versus the distal lung is 2.5-fold higher than in healthy volunteers. If such signal is not segmented out before histogram rescaling, ventilation distributions may be substantially skewed in patients with restrictive disease. Impact: This research paves the way for redefining the calculation of ventilation distribution in pulmonary imaging by incorporating large airways like the trachea, potentially leading to more precise imaging metrics and improved clinical outcomes for pulmonary diseases.
Comparison of Relaxivity and Image Quality of Brand name vs Generic Ferumoxytol: phantom and in vivo results
Authors: van der Heijden Rianne , Tamada Daiki , Rice James , Reeder Scott
Published: November 2024

Motivation: Ferumoxytol is a superparamagnetic iron-oxide agent increasingly used for MR angiography. Cost can potentially be reduced by using a newly introduced generic ferumoxytol, so long as the relaxivity and image quality are similar. Goal(s): To compare the relaxivity and image quality of brand name ferumoxytol (Feraheme®, AMAG Pharmaceuticals) with generic ferumoxytol (Sandoz), and determine optimal dose and acquisition parameters. Approach: Phantom experiment and in-vivo dose accumulation with flip angle optimization, using an intra-individual cross-over design. Results: No clinically relevant differences in relaxivity and MR angiography image quality were observed between ferumoxytol agents. The optimal flip angle and dose are 20° and 5mg/kg, respectively. Impact: Brand name ferumoxytol (Feraheme®, AMAG Pharmaceuticals) and generic ferumoxytol (Sandoz) are interchangeable for MR angiography. The use of a generic agent may lead to reduction in cost.
Resotran - A positive direction for negative contrast: clinically approved Ferucarbotran reintroduced
Authors: Günther Johanna , Hartung Viktor , Augustin Anne Marie , Kampf Thomas , Reichl Teresa , Gruschwitz Philipp , Rückert Martin , Bley Thorsten , Behr Volker , Herz Stefan , Vogel Patrick
Published: November 2024

Motivation: Contrast agents allow a significant improvement of MRI performance. Resotran is a new iron oxide-based and biocompatible MRI contrast agent that is now commercially available in Europe, which still needs to be characterized in more detail. Goal(s): Classification of the performance of Resotran compared to Resovist. Approach: Analyzation and characterization with various spectroscopic and imaging methods. Results: Resotran shows a comparable performance to the former liver contrast agent Resovist. Furthermore, it was shown that Resotran is feasible as a tracer for the new imaging modality magnetic particle imaging (MPI). This is an important step towards paving the way for MPI in clinical routine. Impact: In this work it is shown that the new clinically approved contrast agent Resotran shows a comparable performance as the well-known contrast agent Resovist by a detailed comparison applying different spectroscopic characterization methods.
The altered brain activity in children with electrical status epilepticus during sleep: a preliminary study of resting-state fMRI
Authors: Mo Tong , Deng Kan , Wang Xiaoyu , Zhao Xiance , Zhuang Yijiang , Lin Jieqiong , Zeng Hongwu
Published: November 2024

Motivation: The micro-structure alteration related to cognitive function impairment, and the mechanism of functional impairment in children withESES remains unclear. Goal(s): To investigate the brain activity in children with ESES, and the associations of the brain activity with cognitive performance. Approach: We observed the ReHo difference between the ESES group and the HCs. And the correlation analysis was used to explore the relationship between Reho values and cognitive test. Results: Compared with HCs, patients with ESES showed ReHo alteration in some brain regions. The correlation analysis revealed that increased ReHo in the right frontal gyrus was correlated with the decreased PRI. Impact: The distinct changes of spontaneous brain activity were measured by ReHo, which may be further suggest that the potential of RS-fMRI as a novel biomarker tool for identifying cognitive impairments on neural aspect.
Mapping Metabolite and Neurotransmitter Alterations in Mesial Temporal Lobe Epilepsy Using Optimized Multi-TE MRSI: A Preliminary Study
Authors: Wang Zepeng , Zhao Ruiyang , Li Xinyu , Anderson Aaron , Huesmann Graham , Lam Fan
Published: November 2024

Motivation: Multimodal imaging integrating molecular information promises to improve seizure foci lateralization and disease progression monitoring for mesial temporal lobe epilepsy (mTLE). Goal(s): To evaluate the feasibility of a multi-TE MRSI method optimized for simultaneously mapping metabolites and neurotransmitters in mTLE. Approach: Volumetric multi-TE MRSI and structural MRI data were acquired and analyzed for an mTLE cohort. Regional analysis was performed to quantified molecular maps and hippocampus volumetrics. Results: Reduced NAA/Cr ratios were observed for the ipsilateral hippocampous (epileptic side), consistent with prior findings and overall reduced hippocampus volumes. Reduced Glx/Cr ipsilaterally was observed. Interesting differences in anterior vs. posterior hippocampus were also reported. Impact: We demonstrated the feasibility of a new MRSI technique for mapping metabolic alterations in mTLE patients. Initial results support promise for improved lateralization and better understanding biochemical mechanisms of the disease using MRSI.
Ultra-fast SWI using 3D-EPI and CAIPIRINHA: a feasibility study at 3-tesla
Authors: Nair Sreekanth Madhusoodhanan , Binesh Nader , Jin Jin , Han Fei , Gombos Elaina , Renner Brian , Subhi Mustafa , Al-Louzi Omar , Kaisey Marwa , Sicotte Nancy , Li Debiao , Maya Marcel , Sati Pascal
Published: November 2024

Motivation: Conventional gradient echo SWI has a slow acquisition speed, thus limiting the minimal scan time achievable. However, accelerated 3D-EPI sequence can perform fast MR acquisition. Goal(s): In this study, we evaluated the feasibility of SWI-EPI to generate ultra-fast susceptibility weighted images. Approach: SWI-EPI combines a 3D (muti-shot) EPI sequence with CAIPIRINHA acceleration to significantly reduce the scan time. Results: A significant reduction in scan time (up to 70%) was achieved with similar image quality and without any apparent artefacts, thus confirming the feasibility of ultra-fast SWI for future clinical neuro-applications at 3T. Impact: This study demonstrates the feasibility of ultra-fast SWI-EPI at 3T.
Accelerated Diffusion-Weighted MRI at 7T: Joint Reconstruction for Shift-Encoded Navigated Interleaved Echo Planar Imaging (JETS-NAViEPI)
Authors: Tan Zhengguo , Liebig Patrick , Heidemann Robin , Laun Frederik , Knoll Florian
Published: November 2024

Motivation: Diffusion-weighted MRI suffers from limited spatial resolution, residual geometric distortion, and long acquisition. Goal(s): To develop high spatial-angular-temporal resolution DW-MRI at 7T. Approach: We developed ky-shift encoding and navigated interleaved EPI (NAViEPI) with consistent echo spacing, enabling efficient sampling and minimal distortion mismatch between echoes. We developed joint reconstruction with locally low-rank regularization, encompassing multi-band slices and multiple diffusion directions. Results: We achieved (1) whole brain 3-scan trace acquisition at a resolution of 0.5 x 0.5 x 2.0 mm3 and 98 seconds, and (2) 3-shell 126 diffusion encodings with 1.0 mm isotropic resolution and 22 minutes scan time. Impact: JETS-NAViEPI enables accelerated submillimeter resolution in vivo brain DW-MRI at 7T, offering both clinically relevant 3-scan trace and neuroscientific DTI protocols.