bluuebunny/crossref_metadata_2025 huggingface dataset:
Positive Effect of Weight Loss on Knee Articular Cartilage – a Three-Year Follow-Up Using T2 Relaxation Time
Authors: Mäkelä Eetu , Casula Victor , Kemppainen Ahti , Haapea Marianne , Nieminen Miika
Published: November 2024

Motivation: Weight loss has been shown to be beneficial for knee symptoms and reducing cartilage degeneration. Goal(s): To examine the impact of weight-loss in obese subjects on articular cartilage in the tibiofemoral joint using T2 relaxation time mapping. Approach: Knees of 65 obese patients undergoing either bariatric surgery or conservative weight loss regimens were imaged at 3T before and three years after treatment. Changes in T2 were assessed in tibiofemoral cartilage. Results: A reduction in body mass index (BMI) was associated with shortened T2 values in tibia, indicating that weight loss may result in improved cartilage quality. Impact: The findings provide supporting evidence for the benefits of weight loss for cartilage health and have relevance in the context of osteoarthritis prevention and treatment.
Quantitative MRI of cartilage in ACL reconstructed patients using 3D ultrashort echo time T1 (UTE-T1) and magnetization transfer ratio (UTE-MTR)
Authors: Malhi Bhavsimran , Silva Livia , Silva Melissa , Athertya Jiyo , Moazamian Dina , Ma Yajun , Jerban Saeed , Chang Eric , Bukata Susan , Covey Dana , Chung Christine , Du Jiang
Published: November 2024

Motivation: Post traumatic osteoarthritis is a common complication of ACL injury. There is limited research on the early degenerative changes in cartilage of ACL injured knees. Goal(s): To develop novel biomarkers for identifying early cartilage damage in ACL reconstructed knees. Approach: We employed ultrashort echo time magnetization transfer ratio (UTE-MTR) and UTE-T1 sequence to study the knee articular cartilage in ACL reconstructed patients. Results: UTE-T1 and UTE-MTR can be used as quantitative biomarkers for assessing cartilage damage. Reduced MTR and increased T1 values indicate cartilage damage which is otherwise not appreciated on morphological imaging. Impact: UTE-T1 and UTE-MTR sequences can detect early cartilage damage, which could help us better understand the development of post-traumatic osteoarthritis.
The Association of Cartilage Volume with Knee Pain in Osteoarthritis: An Atlas-Based vs Native Approach
Authors: Peake Edward , Auer Dorothee
Published: November 2024

Motivation: This research investigates the limited association between cartilage volume and knee pain in osteoarthritis, potentially confounded by anatomical variability. Goal(s): To enhance the correlation between MRI-derived cartilage volumes and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) pain scores using a knee atlas for image registration. Approach: Using data from the Osteoarthritis Initiative, MRIs of subjects with OA were registered to an anatomical template. The atlas-based measurements were compared with traditional methods to assess the impact on correlation with WOMAC pain scores. Results: Atlas registration resulted in more consistent cartilage volume measures, reducing variability, and doubling the correlation with WOMAC pain scores. Impact: In knee osteoarthritis the registration of MRIs to an anatomical template significantly increases the association between cartilage volumes and osteoarthritis pain scores, enabling more accurate and sensitive detection of pain-related cartilage changes, potentially influencing OA management and therapy development.
Design of an Open-transmit / 24-channel flexible receiver head coil for MRI/fMRI of somatosensory and motor cortex at 5T
Authors: Wei Zidong , Zhang Zhilin , Chen Qiaoyan , Wang Cuiting , Zhang Xiaoliang , Liu Xin , Wu Jinglong , Zheng Hairong , Li Ye
Published: November 2024

Motivation: Functional magnetic resonance imaging (fMRI) is a non-invasive in vivo functional mapping technique, which afforded a high-quality glimpse of the cortex. Goal(s): Sampling brain activity across cortical layers by using proposed RF coilApproach: The Open-Face birdcage coil was designed by removing and adjusting the legs of the 16-rung high-pass birdcage coil. The 24ch flexible receive array was designed for high spatiotemporal-resolution MRI/fMRI at cortical region. Results: In this study, we designed and constructed an open-transmit and 24 channel flexible receiver head coil assembly for human somatosensory and motor cortex in vivo cortical imaging on a whole body 5T scanner. Impact: SNR maps, T2* weighted images and fMRI images were acquired with the proposed coil assembly, which were compared with those using a quadrature birdcage transmit/48-channel receiver coil assembly.
Biphasic training for awake imaging using a dual-imaging system reveals neurovascular uncoupling and anesthesia effects in healthy mice
Authors: Mandino Francesca , Shen Xilin , Desrosiers-Gregoire Gabriel , O'Connor David , Mukherjee Bandhan , Ha Yonghyun , Qu An , Onofrey John , Papademetris Xenophon , Chakravarty Mallar , Strittmatter Stephen , Lake Evelyn
Published: November 2024

Motivation: Most of rodent-fMRI is acquired under anesthesia, to minimize motion and stress. However, anesthesia hinders mouse-to-human translatability, since most of human fMRI is conducted whilst awake. Goal(s): Here we aim to develop a biphasic protocol for conducting awake rodent-fMRI in mice and simultaneously recording mesoscopic calcium imaging data. Approach: The animals undergo a first training and a refresher a few weeks later. Brain function is analyzed in simultaneous fMRI and mesoscopic calcium imaging measurements. Results: Having a refresher training improves motion in the scanner. The two measures of brain function show interesting patterns over time, with partial agreement and some clear disagreement. Impact: Rodent-fMRI is typically done under anesthesia to minimize stress and motion. This limits mouse-human translatability (since humans are usually scanned awake). Here, we develop a biphasic approach to train mice to awake imaging, using simultaneous fMRI and Calcium imaging measures.
Whisker pad stimulation elicits brain-wide cross-sensory activation in awake rats measured with zero echo time fMRI
Authors: Paasonen Jaakko , Valjakka Juha , Salo Raimo , Paasonen Ekaterina , Michaeli Shalom , Mangia Silvia , Gröhn Olli
Published: November 2024

Motivation: Sensory research has typically focused on one system at a time, and basic mechanisms related to interactions between sensory systems remain poorly understood. Goal(s): To detect and characterize brain-wide cross-sensory interplay, and to study how non-core circuits react to varying input into the core circuit. Approach: Classical whisker pad stimulation in head-fixed awake and anesthetized rats in combination with a large number of fMRI measurements. Results: We detected cross-sensory brain-wide activations to whisker pad stimulation. The activation profile of many non-core regions differed from that of the core circuit. Importantly, some features of cross-sensory interplay were not visible under anesthesia. Impact: Cross-sensory activations are gaining increasing attention in imaging studies. Previously, multisensory interplay may have gone unnoticed, as the focus has been in the primary pathway. Our results also emphasize the importance of avoiding anesthesia in preclinical cross-sensory research.
Investigating timing of BOLD fMRI responses in individual cortical vessels to short and long stimulus durations
Authors: Varadarajan Divya , Proulx Sebastien , Wighton Paul , Hu Zhangxuan , Chen Jingyuan , Bollmann Saskia , Berman Avery , Polimeni Jonathan
Published: November 2024

Motivation: Typical fMRI data observes hemodynamics from multiple vascular compartments in each voxel, however understanding the link between neuronal and vascular dynamics will require vessel-specific measurements. Goal(s): To investigate the timing and amplitude of hemodynamic responses within individual arteries and veins of the human cortex and assess how they change with stimulus duration. Approach: We applied single-vessel fMRI with multiple echoes to separate inflow and BOLD components, and distinguished intravascular and extravascular dynamics in and around arteries and veins. Results: We observed faster dynamics in arteries, and a post-stimulus undershoot in all vessels, potentially providing new insights into hemodynamics in the human brainImpact: Knowledge about hemodynamics within individual vascular compartment is provided by invasive microscopy in small-animal models, and less is known about hemodynamics in humans. Here we present vessel-specific measurements of hemodynamics in humans and reveal unexpected features in the fMRI response.
Assessment of the macrovascular contribution to resting-state fMRI functional connectivity at 3 Tesla
Authors: Zhong Xiaole , Tong Yunjie , Chen J. Jean
Published: November 2024

Motivation: Resting-state fMRI (rs-fMRI) based functional connectivity (fcMRI) is widely used to image neuronal networks, but it could be biased by the contribution of macrovasculature. Goal(s): This study aims to provide a better understanding of vascular rs-fMRI contributions and their interpretation. Approach: Our study evaluated macrovascular contributions to experimental rs-fcMRI data. Results: We found both arteries and veins to substantially modulate fcMRI metrics. We also found that vascular-driven fcMRI spatial variance was disproportionately high given the low vascular voxel count. In particular, veins contribute more to connectivity strength than arteries, while arteries contribute more to spatial variance than veins. Impact: The macrovasculature was previously shown to modulate functional connectivity and reduce its neuronal specificity, but a systematic analysis is still lacking. This study demonstrates macrovascular contributions at 3 Tesla and paves the way for the correction of bias in rs-fMRI.
A repository-integrated tool for monitoring imaging protocol compliance in a multi-centre whole-body MRI myeloma study
Authors: Keaveney Sam , McHugh Damien J , Rata Mihaela , Dragan Alina , Blackledge Matthew , Scurr Erica , Winfield Jessica M , Koh Dow-Mu , Doran Simon J , Berks Michael , O'Connor James PB , King Alexander , Rennie Winston J , Gaba Suchi , Suresh Priya , Malcolm Paul , Davis Amy , Nilak Anjumara , Shah Aarti , Gandhi Sanjay , Albrizio Mauro , Drury Arnold , Pratt Guy , Cook Gordon , Roberts Sadie , Hall Andrew , Jenner Matthew , Brown Sarah , Kaiser Martin , Cristinacce Penny L Hubbard , Messiou Christina
Published: November 2024

Motivation: Standardisation of imaging protocols in multi-centre studies is challenging, which can hamper clinical translation. Goal(s): This study aimed to develop and demonstrate a software tool that automatically assesses imaging protocol compliance. Approach: The tool was containerised and integrated into an imaging repository. It was applied to a dataset from a whole-body MRI (WB-MRI) myeloma study, which included 174 examinations acquired across 10 sites with scanners from three manufacturers. Results: The software successfully identified some parameters and sites where persistent deviations occurred, although 88% of examinations were conducted according to the relevant clinical guidelines with good overall compliance to site-specific protocols. Impact: Repository-integrated software is presented for automated monitoring of imaging protocol compliance to support standardisation in multi-centre studies and clinical translation. A multi-centre whole-body MRI study demonstrates good compliance that could have been improved further with proactive monitoring using this tool.
Detecting IDH1 Mutations in Gliomas: Insights from J-Difference Editing MEGA-PRESS 1H-MRS
Authors: Guo Jia , Mela Angeliki , Qie Zhonghui , Yang Yanting , Mahajan Aayushi , Humala Nelson , Canoll Peter
Published: November 2024

Motivation: Detecting isocitrate dehydrogenase 1 (IDH1) mutations via in vivo MRI can significantly aids glioma diagnosis and treatment strategies. Goal(s): To investigates the use of MEGA-PRESS sequences to non-invasively charaterize the metabolic profile of IDH1 mutation glioma. Approach: We measured 2-hydroxyglutarate (2HG), glutamate+glutamine (GLX), GABA and glutathione (GSH) inside the glioma from an IDH1(R132H)-mutant and an IDH1-wildtype murine models. Results: The results unveil distinctive metabolic changes in IDH1 mutation tumors, including elevated 2HG, GLX/GABA ratio, and reduced GSH. These findings offer potential biomarkers for precise diagnosis and therapeutic strategies, highlighting the significant role of MEGA-PRESS in the studies of glioma. Impact: The study identifies 1H MRS-based biomarkers for non-invasive detection of IDH1 mutation tumors using the MEGA-PRESS sequence. It provides insights into metabolic changes and neurochemical imbalances, aiding early diagnosis, treatment guidance, and monitoring, thus advancing precision oncology.
1H MR spectroscopy and IVIM-DWI to evaluate the effect of a choline kinase inhibitor and temozolomide therapy in a mouse model of glioblastoma
Authors: Alrashidi* Tareq , Bhaduri* Sourav , Gash Elisabeth Non , Moothanchery Mohesh , Ball Christopher , Maguire Mahon , Ressel Lorenzo , Poptani Harish
Published: November 2024

Motivation: There is a lack of comprehensive understanding regarding the impact of choline kinase inhibition and standard chemotherapy on preclinical GBM models. Goal(s): The primary goal of this study was to elucidate the treatment response mechanism in a preclinical GBM mouse model. Approach: MRS and IVIM-DWI were used for monitoring metabolic and microstructural changes in a preclinical GBM model by single or combination therapy with a choline kinase inhibitor and TMZ. Results: Our findings indicate that the combination therapy is the most effective treatment regimen. This study contributes to a better understanding of treatment response mechanisms and underscores the potential of non-invasive MRI methods. Impact: Targeting ChoKα inhibition and the damage of DNA replication (TMZ) promises to be an alternative in the treatment of GBM. This research also highlights the importance of MRS and IVIM-DWI as promising non-invasive methods to assess therapeutic effects on GBM.
Predictions of Human Prostate Cancer with MRS Metabolomics from Biopsies After More Than 5-Year Follow-Up
Authors: Zhang Ella , Lu Jiaqi , Zhou Jonathan , Wu Chin-lee , Feldman Adam , Cheng Leo
Published: November 2024

Motivation: Evaluations of prostate cancer (PCa) with traditional transrectal ultrasound (TRUS) and multiparametric MRI-ultrasound (mpMRI-US) fusion biopsies may produce false-positives or false-negatives, thereby preventing optimal and timely treatments. Goal(s): To evaluate PCa metabolomics from TRUS and fusion biopsy cores using magnetic resonance spectroscopy (MRS) to identify potential metabolomic biomarkers for better characterization of PCa. Approach: Using ex vivo MRS, we measured 432 prostate biopsy cores from patients suspicious of PCa between 4/2006 and 10/2018. Results: MRS metabolomics could differentiate between benign and malignancy, reflect malignant status from benign cores, and allowed for predictions of future PCa from benign biopsies. Impact: Our results demonstrate that MRS-based metabolomic evaluations have the potential to detect PCa years earlier than standard TRUS and fusion biopic techniques, and improve PCa active surveillance based on prostate biology.
The Role of Quantitative Imaging for Early Detection of Prostate Cancer Progression in Patients on Active Surveillance
Authors: Kimbel Isabella , Wallaengen Veronica , Zacharaki Evangelia , Breto Adrian , Algohary Ahmad , Gaston Sandra , Kryvenko Oleksandr , Castillo Patricia , Abramowitz Matthew , Pollack Alan , Punnen Sanoj , Stoyanova Radka
Published: November 2024

Motivation: Patients on Active Surveillance (AS) for prostate cancer have a high risk of cancer progression to treatment. There is a need for additional tools to risk stratify AS patients. Goal(s): To evaluate the Habitat Risk Score (HRS) method for automatic identification of lesions for early detection of AS progressors in a prospective trial. Approach: HRS was assessed in patients that progressed in the 1st, 2nd or 3rd year of AS. Results: In 40% of the patients, HRS identified a dominant lesion that was not targeted during biopsy. The study illustrates the quantitative power of HRS as compared to PIRADS. Impact: Integrating Habitat Risk Score (HRS) in Active Surveillance for prostate cancer has the potential to significantly reduce the number of surveillance biopsies. HRS facilitates the detection of progression through assignment of robust biopsy targets and quantification of tumor habitat changes.
Time-resolved multifrequency cardiac MR elastography of the in-vivo human heart using a segmented gradient echo spiral sequence.
Authors: Anders Matthias , Warmuth Carsten , Meyer Tom , Tzschätzsch Heiko , Pfeuffer Josef , Schulz-Menger Jeanette , Braun Jürgen , Sack Ingolf
Published: November 2024

Motivation: Abnormal changes in myocardial stiffness during the cardiac cycle are a potential biomarker for cardiac diseases. However, there is currently no established MR-method for time-resolved mapping of cardiac stiffness. Goal(s): To demonstrate the reproducibility of time-resolved stiffness mapping of the in-vivo human heart over the cardiac cycle by MR elastography (MRE). Approach: Eleven healthy volunteers were examined twice using multifrequency cardiac-triggered, segmented gradient echo spiral MRE for stiffness mapping of the left ventricular myocardium in a short-axis view. Results: Excellent, good, and moderate reproducibility was achieved for isovolumetric contraction, systolic, and diastolic phases, respectively. Significant differences among all phases were apparent. Impact: The achieved high reproducibility of cardiac multifrequency MRE, together with its ability to identify distinct time-resolved stiffness levels during the cardiac phases of isovolumetric contraction, systole and diastole, could potentially detect stiffness related cardiac pathology in early disease stages.
Biomechanical tumor hallmarks for the clinical diagnosis of glioma by high-resolution multifrequency MR elastography
Authors: Shahryari Mehrgan , Meyer Tom , Gottheil Pablo , Hain Elisabeth , Käs Josef , Siebert Eberhard , Prinz Vincent , Sack Ingolf
Published: November 2024

Motivation: Previous studies using MR Elastography (MRE) have suggested that gliomas exhibit reduced stiffness and viscosity. However, the interplay between micromechanical tumor changes that determine the macroscopic mechanical properties measured by MRE remains unclear. Goal(s): This study aims to investigate the relationship between viscoelastic parameters measured MRE in-vivo and histopathologically quantified parameters in glioma. Approach: High-resolution multifrequency MRE with quantified histopathology was prospectively performed in 23 patients with glioma. Results: Stiffness and viscosity in gliomas are associated with increased cell elongation, micro-vessel density, and apoptotic rate suggesting unjamming, neovascularization and cell proliferation as biomechanically sensitive tumor hallmarks for clinical diagnosis. Impact: In this study, we demonstrated that viscoelastic parameters, quantified by MR Elastography, provide insights into cell mobility, cellularity, mitotic and apoptotic rates, as well as vascularization of gliomas in-vivo. This technique holds promise for future clinical diagnosis of neurotumors.
Rapid, open-source, cross-platform 3D multiparametric mapping for multisite neuroimaging
Authors: Fujita Shohei , Gagoski Borjan , Nielsen Jon-Fredrik , Zaitsev Maxim , Jun Yohan , Cho Jaejin , Yong Xingwang , Milshteyn Eugene , Imam Shaik , Liu Qiang , Chen Qingping , Rathi Yogesh , Bilgic Berkin
Published: November 2024

Motivation: To address the unmet need for a cross-platform, multiparametric technique to facilitate data harmonization across different sites. Goal(s): To implement and evaluate a fully transparent 3D multiparametric mapping for multisite neuroimaging. Approach: A multiparametric mapping technique, 3D-QALAS, was implemented in Pulseq. The acquired T1 and T2 maps were compared within-scanner, cross scanners, software versions, sites, and vendors. Results: The Pulseq implementation exhibited significantly higher reproducibility than vendor-native implementations, particularly for T2 values, in both phantom and in vivo studies. This approach enabled ADNI-compliant field-of-view sizes with 1mm isotropic resolution within 5 minutes, while maintaining a cross-platform coefficient of variation below 4%. Impact: An open-source implementation across different vendors and scanners, along with a consistent reconstruction and fitting pipeline, improved measurement reproducibility. This approach facilitates data harmonization, version control and error-propagation assessment, making it also suitable for extracting quantitative information for downstream analysis.
Normative trajectories of R1, R2*, and Susceptibility values of the healthy human brain cortex
Authors: Chen Xinjie , Lu Po-Jui , Ocampo-Pineda Mario , Weigel Matthias , Chan Kwok-Shing , Cagol Alessandro , Zwiers Marcel , Jansen Michelle G. , Norris David G. , Schädelin Sabine , Barakovic Muhamed , Kuhle Jens , Kappos Ludwig , Melie-Garcia Lester , Granziera Cristina , Marques José P
Published: November 2024

Motivation: Quantitative MRI (qMRI) offers sensitive and specific measures to study age-related microstructural changes in the brain. However, models assessing age trajectories in qMRI brain properties are often incomparable among centers. Goal(s): Develop normative models reflecting aging trajectories and assess the impact of bi-centric, non-fully matched protocols in brain aging studies. Approach: Investigating age trajectories in cortical regions using polynomial regression models, focusing on quantitative R1, R2*, and susceptibility mapping (QSM). Results: We validated data harmonization by observing the impact on normative trajectories using bicentric data, where we noted significantly different maturation and aging inflections for R1 and R2* trajectories across cortical regions. Impact: This bi-centric, multi-parameter qMRI study investigates age-dependent variations across cortical regions, offering a valuable reference for subsequent qMRI aging research and emphasizing age effects on the cortical surface.
Cardiac Magnetic Resonance Fingerprinting for Simultaneous T1 and T2 Mapping at 0.55T
Authors: Castillo-Passi Carlos , Velasco Carlos , Tripp Donovan , Kunze Karl , Neji Radhouene , Irarrazaval Pablo , Botnar René , Prieto Claudia
Published: November 2024

Motivation: Cardiac MRF (cMRF) allows for comprehensive myocardial tissue characterization in a single scan and has been investigated at 1.5T/3T. However, cMRF has not been demonstrated at low-field. Goal(s): Investigate the feasibility of a bSSFP-cMRF sequence for simultaneous T1 and T2 mapping at 0.55T. Approach: The proposed approach considers bSSFP radial readouts with varying IR and T2-preparation pulses over 16 heartbeats. bSSFP-cMRF was evaluated in phantoms and healthy subjects in comparison to reference maps. Results: bSSFP-cMRF at 0.55T shows excellent agreement with reference values in phantom and good image quality in healthy subjects with T1 and T2 values agreeing with the literature. Impact: The simultaneous quantification of T1 and T2 at 0.55T in a single cardiac-MRF scan of 16s could provide an alternative to higher field scanners, allowing for a more accessible way to assess cardiovascular disease.
Using Aleatoric Uncertainty to Aid Deep Learning based T1rho Mapping and Analysis in the Liver
Authors: Huang Chaoxing , Wong Vincent , Chan Queenie , Chu Winnie , Chen Weitian
Published: November 2024

Motivation: The utility of uncertainty to ensure a reliable learning-based parametric mapping in quantitative MRI is underexplored. Goal(s): This study aimed to develop a reliable method for quantitative T1rho mapping of liver using uncertainty-based deep learning. Approach: We proposed a parametric map refinement approach that trained the model probabilistically to estimate uncertainty in predicted T1rho values. The uncertainty map was used to enhance mapping performance and identify unreliable values in the region of interest. Results: Testing on 51 patients with liver fibrosis showed a mapping error of less than 3% and simultaneous uncertainty estimation. Impact: Our work demonstrates potential of saving scan time while preserving T1rho quantification accuracy. It is also shown that incorporating uncertainty estimation in the T1rho mapping network can improve the reliability of predicted values.
A modelling and experimental framework to investigate the sensitivity of steady-state diffusion MRI to microstructure
Authors: Zheng Zhiyu , Tachrount Mohamed , Miller Karla , Cottaar Michiel , Tendler Benjamin
Published: November 2024

Motivation: Diffusion-weighted steady-state free precession (DW-SSFP) has demonstrated higher SNR-efficiency vs the diffusion-weighted spin-echo (DW-SE) in post-mortem tissue. However, its sensitivity to microstructural features has not been comprehensively investigated. Goal(s): To develop an investigation framework to quantify DW-SSFP’s sensitivity to microstructure. Approach: We combined Monte-Carlo simulations with phantom experiments incorporating diffusion hinderance/restriction and an ex-vivo mouse brain, comparing the estimated diffusion attenuation of DW-SSFP vs a DW-SE sequence with matched gradient waveforms and diffusion timings. Results: DW-SSFP exhibited higher diffusion attenuation vs DW-SE in all tested substrates when gradient waveforms/timings are matched, suggesting its unique signal forming mechanisms may be highly sensitive to microstructure. Impact: We present a framework combining Monte-Carlo simulations with experiments to characterise the sensitivity of diffusion-weighted steady-state free precession (DW-SSFP) to microstructure. DW-SSFP demonstrates greater signal attenuation versus a gradient waveform/timing-matched DW-SE across different substrates, demonstrating its potential for microstructural imaging.
In-silico study of internal gradient distribution effects on diffusion-weighted signals of white matter tracts models at 9.4 T
Authors: Fajardo Jesus , Alvarez Gonzalo A.
Published: November 2024

Motivation: Non-invasively detecting tissue microstructure changes associated with pathologies holds immense diagnostic promise. Our approach complements conventional DWI methods by capturing distinct microstructural information. Goal(s): We investigate the relationship between axon microstructure parameters and Internal Gradients distributions' influence on MRI signals. Approach: We employed the Finite Perturber Method (FPM) to calculate intravoxel magnetic gradients and MonteCarlo simulations to simulate the spins diffusion using a MGSE sequence. Results: Our findings demonstrate up to 2.5 % signal variations when incorporating Internal Gradient Distribution terms, offering insights into signal behavior with varying microstructure parameters. Impact: The complementary findings of addressing non-invasive tissue-microstructure changes based on probing internal gradients paves the way for early pathological detection. This empowers clinicians to in-depth investigations, transforming our approach to diagnostics and enhancing healthcare outcomes.
Elucidating Micro-scale Fiber Trajectories at 16μ in Anisotropic Phantoms via Structural Tensor Analysis
Authors: Pathak Sudhir , Pohmann Rolf , Avdievitch Nikolai , Scheffler Klaus , Zuccolotto Anthony , Wu Yijen , Schneider Walter
Published: November 2024

Motivation: This study utilizes a custom-designed fiber crossing configuration based on anisotropic textile hollow fiber phantom and harnesses high-resolution 14T MRI to unravel manufactured fiber crossings at a microscopic scale. Goal(s): By applying structural tensor analysis in combination with eigenvalue decomposition, we have estimated underlying fiber orientations and visualized in multi-planar, directional-color-encoded maps. Approach: This innovative approach yielded precise angular measurements across the volume to delineate the expected fiber orientation and crossing angles, thereby validating the structural tensor method's efficacy in capturing complex fiber architecture within a controlled environment. Results: This Phantom can provide a ground truth for validating diffusion MRI based crossing assessments. Impact: This research presents a pivotal advancement for validating MRI-based fiber crossing, offering a novel phantom design for assessing the accuracy and limitations of MRI methods in resolving complex fiber architectures in biological tissues.
An anisotropic capillary based phantom for validation of diffusion-relaxation models
Authors: Seland John , Maximov Ivan
Published: November 2024

Motivation: We aim to create a universal procedure for experimental verification of diffusion models using model systems based on glass capillaries. Goal(s): Spatially ordered glass capillaries mimics the characteristic geometry of white matter and are ideal for performing a 'stress test' of various diffusion models. We aim to verify this through diffusion and relaxation measurements at varying spatial directions and time scales. Approach: Combined diffusion- and relaxation-weighted MRI based measurements verify the geometry of the glass capillaries at different spatial scales. Results: The glass capillary phantom was established as a ground truth model for modelling of white matter at different diffusion and relaxation regimes. Impact: Glass capillaries present a unique object with simple physical and geometrical features mimicking white matter. We tested a glass capillary phantom in terms of a diffusion-relaxation model using conventional sequences and provide a simple theoretical interpretation of experimental results.
How does dMRI signal evolve during diffusion encoding: theoretical analysis and numerical simulations for Gaussian diffusion
Authors: Liu Fan , Chen Li , Li Sisi , Zheng Quanshui , Guo Hua , Xu Junzhong , Shi Diwei
Published: November 2024

Motivation: Until now, most attention has been focused on the final dMRI signals acquired, ignoring the signal evolution during diffusion encoding. However, the methods, which incorporated water exchange between compartments into modelling to extract more comprehensive tissue information, need to consider the signal evolution within the different compartments, as described in Karger model. Goal(s): Figure out the dMRI signal evolution in the simplest case: Gaussian diffusion. Approach: Theoretical analysis, Monte-Carlo and finite difference simulations. Results: Signal-evolution curves provided by analytical expressions and numerical simulations are consistent. An “observation-size” effect emerges, the signal-evolution curve depends on the spatial size of the observation area. Impact: Clarifying the actual dMRI signal evolution during diffusion encoding will inspire us to revisit the theoretical framework of Karger model. The results show that it is necessary to revise the current Karger-model-based methods for the “observation-size” effect.
Coarse-graining with time-dependent diffusion reveals signatures of demyelination and axonal loss
Authors: Coronado-Leija Ricardo , Lee Hong-Hsi , Fieremans Els , Novikov Dmitry
Published: November 2024

Motivation: Time-dependent diffusion $$$D(t)$$$ is sensitive to brain microstructure. Using Monte Carlo (MC) simulations, $$$D(t)$$$ has been shown to provide information about structural changes caused by pathological conditions. Goal(s): To establish the relation between the parameters of $$$D(t)$$$ and the extra-axonal space geometry. Approach: We solve the Fick-Jacobs equation in the effective medium framework, connect $$$D(t)$$$ to correlations of density and local diffusivity, and validate with Monte-Carlo simulations. Results: Time-dependence of $$$D(t)$$$ is quantitatively related to geometric characteristics of axonal packing, demyelination and axonal loss. Impact: By coarse-graining the extra-axonal space, time-dependent diffusion explores the geometry relevant for demyelination and axonal loss, enabling quantifying axonal microstructure.
Free-running motion-resolved 5D whole-heart anatomical MRI at 3T without contrast agent
Authors: Ogier Augustin , Quesada Isabel Montón , Sieber Xavier , Calarnou Pauline , Ledoux Jean-Baptiste , Milani Bastien , Roy Christopher , Yerly Jérôme , Stuber Matthias , van Heeswijk Ruud
Published: November 2024

Motivation: Routine cardiac function assessment uses breath-held 2D cine imaging. Self-gated free-running sequences have recently been proposed to simplify the workflow. However, at 3T, GRE-based sequences require contrast agents to achieve blood-myocardium contrast. Goal(s): This study introduced a contrast-agent-free acquisition for assessing cardiac anatomy and function at 3T. Approach: Based on an interrupted free-running sequence, the proposed approach integrates T2 preparation and recovery modules to optimize blood-to-myocardium-contrast. A compressed-sensing-based reconstruction was used to generate 5D images of the whole heart. Results: The framework was validated in 11 healthy volunteers, where it demonstrated slightly lower contrast but enabled effective left-ventricle segmentation and exhibited high reproducibility. Impact: The proposed study introduces a contrast-agent-free method for a comprehensive 5D assessment of cardiac anatomy and function at 3T in a 5-minute acquisition. Demonstrating high agreement with the routine method, this approach holds promise for enhancing the overall patient management.
Regional fat distribution is associated with subclinical left atrial and left ventricular diastolic dysfunction in early adult obesity
Authors: Liu Jing , Peng Liqing , He Wenzhang , Li Xue
Published: November 2024

Motivation: Whether obese subjects with no clinical signs or comorbidities have diastolic dysfunction is unclear. Goal(s): We non-invasively assess diastolic function in adults with uncomplicated obesity and evaluate its association with fat distribution. Approach: Left atrial (LA) and left ventricular (LV) strain and volume-time curve using cardiac magnetic resonance were compared. Results: The obese patients had impaired diastolic function, manifested as lower LV diastolic strain rates and peak filling rate index and declined LA reservoir and conduit function compared with controls. Central fat has a negative association while peripheral fat has a positive association on diastolic function. Impact: CMR-derived feature tracking and volume-time curve non-invasively detected subclinical diastolic dysfunction in early adult obesity with preserved LVEF. This study also suggests that recognizing the role of different areas of fat on the heart may be beneficial for obese patients.
Cardiac–hepatic magnetic resonance findings in children with Kawasaki disease
Authors: Peng Shengkun , Wen Lingyi , Chen Meining , Guo Yingkun
Published: November 2024

Motivation: Kawasaki Disease (KD) is recognized for cardiac and coronary arterial impact, however its influence on the liver remains underexplored, especially in pediatric patients. Goal(s): Use T1 mapping to quantitatively evaluate cardiac-hepatic involvement and myocardial fibrosis in KD patients. Approach: Using a 3T MR scanner, T1 mapping was conducted on the heart and liver of 115 KD patients and 40 controls, with myocardial fibrosis being diagnosed through LGE. Results: KD patients displayed elevated cardiac and hepatic T1 values in both acute and chronic phases compared to controls. These values, in combined with sodium levels, were effective in identifying myocardial fibrosis in KD patients. Impact: This study demonstrated T1 mapping was a noninvasive tool for the comprehensive assessment of cardiac-hepatic involvement and myocardial fibrosis in KD patients.
Modeling Phase Errors for Robust and Efficient Multidimensional MR Fingerprinting for Simultaneous Relaxation and Diffusion Mapping
Authors: Qiu Zhilang , Hu Siyuan , Zhao Walter , Sakaie Ken , Szczepankiewicz Filip , Sun Jessie , Griswold Mark , Jones Derek , Ma Dan
Published: November 2024

Motivation: Diffusion MRI can be corrupted by phase errors due to physiological motion, bulk motion, eddy currents, and other system imperfections, which makes its efficient embedding into MR Fingerprinting challenging. Goal(s): To develop a new approach to correct artifacts in multidimensional MR Fingerprinting (mdMRF) for simultaneous relaxation and diffusion quantification, that obviates cardiac gating, motion compensation, navigators, or data removal. Approach: Modeling potential phase errors using phase offset and phase dispersion during dictionary generation, then quantifying and correcting measured phase errors in dictionary matching. Results: The proposed approach significantly mitigates artifacts in mdMRF diffusion parameter mapping. Impact: Phase error-induced artifacts due to physiological motion, bulk motion, and eddy currents is a key limitation in diffusion MRI. We develop an approach to improve robustness and efficiency of artifact correction in multidimensional MR Fingerprinting for relaxation and diffusion mapping.
Can MR only IR-UTE based BoneView imaging, along with routine MRI, be used to exclude sacroiliac joint (SIJ) pathologies without the need for X-Ray?
Authors: David Sharmila , Gunasingh Monica , Sulalith Chirath , Pallewatte Aruna , Rolla Narayana , Saha Indrajit , Shah Tejas
Published: November 2024

Motivation: For a comprehensive diagnostic imaging investigation of SIJ, neither plain radiographs alone nor MRI alone provide sufficient specificity and sensitivity for accurate diagnosis of traumatic and/or non-traumatic sources of SIJ dysfunction. Goal(s): Our goal is to show that using UTE based BoneView imaging technique, we can sufficiently detect enough structural radiological features of SIJ in non-pathological cases. Approach: 24 patients with non-pathological SIJ were recruited for this study and inter-reader as well as inter modality agreement was computed based on a likert scale by two radiologists. Results: There was high inter reader agreement as well as inter modality agreement. Impact: MR only (IR-UTE based BoneView + routine MR) can be used to exclude patients with pathological SIJs and further investigation is necessary to extend the findings further to pathological cases as well.
Cumulant tensors from the addition of angular momenta: All diffusion invariants in one abstract
Authors: Coelho Santiago , Szczepankiewicz Filip , Fieremans Els , Novikov Dmitry
Published: November 2024

Motivation: The advent of quantitative imaging hinges on revealing the information content of MRI measurements. We provide a complete basis- and hardware-independent “fingerprint" for the diffusion signal up to moderate diffusion-weightings. Goal(s): Find all rotationally invariant information present in the cumulant expansion up to b2. Approach: We classify all invariants of diffusion and covariance tensors in terms of irreducible representations of the group of rotations, discuss their geometric meaning, and relate them to tissue properties. Results: We find a complete set of 21 independent rotational invariants up to b2. Previously studied contrasts are expressed via only 7, while the rest provide novel complementary information. Impact: We map the diffusion covariance tensor onto the addition of angular momenta, and provide all rotational invariants of the cumulant expansion (RICE). RICE apply to >50k publicly available human diffusion MRI datasets, providing new insights into tissue properties.
Data-driven classification of tissue water populations by massively multidimensional diffusion-relaxation correlation MRI
Authors: Narvaez Omar , Yon Maxime , Salo Raimo , Kyyriäinen Jenni , Topgaard Daniel , Sierra Alejandra
Published: November 2024

Motivation: Multidimensional diffusion-relaxation MRI opened new ways to non-invasively study sub-voxel populations of water with distinct MRI signal responses and, by inference, tissue microstructure. However, this technique creates large number nonparametric diffusion-relaxation distributions that are challenging to visualize or translate into microstructure specific maps. Goal(s): The goal of this study is to automatically classify the distribution components for an ex vivo rat brain and compare them with histology to reveal their links to tissue fractions. Approach: To achieve the automatic classification, we use an unsupervised data-driven clustering approach. Results: We successfully separated white matter, gray matter, free water and additional tissue fractions. Impact: Multidimensional diffusion-relaxation MRI combined with data-driven microstructure clustering offers new perspectives in high-specificity studies of healthy and damage tissue beyond the conventional white matter, gray matter, and free-water fractions. This is achieved by exploring the full sub-voxel multidimensional distribution space.
Reconstruction-free segmentation from undersampled k-space using transformers
Authors: Zhang Yundi , Stolt-Ansó Nil , Pan Jiazhen , Huang Wenqi , Hammernik Kerstin , Rueckert Daniel
Published: November 2024

Motivation: High acceleration factors place a limit on MRI image reconstruction. This limit is extended to segmentation models when treating these as subsequent independent processes. Goal(s): Our goal is to produce segmentations directly from sparse k-space measurements without the need for intermediate image reconstruction. Approach: We employ a transformer architecture to encode global k-space information into latent features. The produced latent vectors condition queried coordinates during decoding to generate segmentation class probabilities. Results: The model is able to produce better segmentations across high acceleration factors than image-based segmentation baselines. Impact: Cardiac segmentation directly from undersampled k-space samples circumvents the need for an intermediate image reconstruction step. This allows the potential to assess myocardial structure and function on higher acceleration factors than methods that rely on images as input.
Longitudinal MRA Tortuosity Metric Measurements in a Population-based Study
Authors: Xu Ziyang , Caughey Melissa , Wang Sile , Zhou Xinwei , Qiao Ye
Published: November 2024

Motivation: Current understanding of dolichoectasia has largely been drawn from patients with clinical need for brain imaging in the cross-sectional settings. Goal(s): To characterize the longitudinal changes in brain MRA geometry vessel metrics and their associations with demographic variables, imaging biomarkers and cognitive performance. Approach: Basic demographic and clinical information were compared between two groups w/wo MRI metric measurement change using two-sample t-tests. The associations between MRI metrics and cognitive decline or incidence dementia were tested using logistic regression. Results: MRA geometry vessel metric change was not associated with the cognitive decline over time (3.6-8 years). Baseline cognitive score can predict future cognitive performance. Impact: Clinical predictors of worsening dolichoectasia are unknown. Although MRA geometry vessel metric changes are not significant with cognitive decline, demographic variables show significance on some metric difference. Baseline cognitive score can also predict cognitive change.
Deformation-based morphometry reveals lower brain tissue volume in autopsy confirmed limbic age-related TDP-43 encephalopathy (LATE)
Authors: Tazwar Mahir , Evia Arnold , Ridwan Abdur Raquib , Bennett David , Schneider Julie , Arfanakis Konstantinos
Published: November 2024

Motivation: The association of limbic-predominant age-related TDP-43 encephalopathy neuropathological change (LATE-NC) with brain morphometry has not been thoroughly investigated. Goal(s): To investigate gray and white matter morphometric abnormalities in LATE-NC in a large number of community-based older adults. Approach: This study combined deformation-based morphometry (DBM) in ex-vivo brain MRI and detailed neuropathological data on the same community-based older adults (N=897), and investigated the association of LATE-NC with brain morphometric characteristics using voxel-wise linear regression models. Results: LATE-NC was associated with lower volume in gray and white matter areas of temporal and frontal lobes and basal ganglia, consistent with the known pathological distribution of LATE-NC. Impact: The pattern of morphometric abnormality in LATE-NC that was generated in the present work may potentially be used in combination with other imaging and clinical information towards the development of a marker of this devastating neuropathology.
Magnetic Resonance Elastography Based Measure of Compressibility in Normal Pressure Hydrocephalus and Alzheimer’s Disease
Authors: Karki Pragalv , Murphy Matthew , Cogswell Petrice , Manduca Armando , Ehman Richard , Huston John
Published: November 2024

Motivation: Magnetic resonance elastography (MRE) is typically used to assess shear mechanical properties of a tissue. A new measure related to the compressibility of a tissue could provide new insights into disease processes. Goal(s): To test a new measure related to the tissue compressibility in application to neurological disorders. Approach: A measure of compressibility was defined as the ratio of the magnitude of the divergence over the magnitude of the curl of displacements. Results: Normal pressure hydrocephalus and Alzheimer’s disease displayed distinct patterns of compressibility measure compared to the control group. Impact: An MRE-based compressibility measure demonstrates unique patterns in normal pressure hydrocephalus and Alzheimer’s disease. This may provide new insights into disease processes and guides future research.
Brain arterial remodeling and incident dementia: the Atherosclerosis Risk in Communities (ARIC) Study
Authors: Wang Sile , Caughey Melissa , Xu Ziyang , Zhou Xinwei , Qiao Ye
Published: November 2024

Motivation: We aimed to address the gap in understanding the neurovascular contributions to dementia risk in a US community-based study, recognizing the need to consider arterial geometry factors and cerebral small vessel disease (CSVD). Goal(s): Our study sought to investigate the relationship between brain arterial remodeling and incident dementia risk, focusing on how arterial geometry and CSVD factor into this complex equation. Approach: Our approaches involved analyzing data from a US community-based study to assess the impact of arterial remodeling, arterial geometry, and CSVD on dementia risk. Results: Our study's core findings indicate an increased risk of incident dementia associated with brain arterial remodeling. Impact: Our model is promising for the prediction of cognitive decline and dementia diagnosis based on the MRA measurements.
Moving MRI (mMRI): imaging a moving body with synchronized magnet movement
Authors: Yao Jingting , Kaso Artan , Patel Nikhil , Chen Yin-Ching Iris , Yen Yi-Fen , van der Kouwe André , Merfeld Daniel , Ackerman Jerome
Published: November 2024

Motivation: MRI is largely limited to scenarios involving small-scale bodily movements to minimize artifacts and field-induced physiological effects. Goal(s): We are developing a moving MRI system where the magnet and subject’s head remain stationary with respect to each other during large-scale motion. Approach: Utilizing a compact, dry 1.5T magnet, we built an apparatus that tilted the entire magnet assembly, including the cold head, gradient/shim/RF coils, and the subject, up and down during scanning. Results: We demonstrated the ability to scan phantoms and live animals while the magnet is in motion and to correct for imaging artifacts caused by tilting the magnet. Impact: Our proof-of-concept prototype moving MRI system supports the future viability of developing a human-scale moving MRI system, which has the potential to advance studies in vestibular research, traumatic brain injury, and brain-behavior interactions, among other areas.