bluuebunny/crossref_metadata_2025 huggingface dataset:
Amide proton transfer weighted signal of multiple sclerosis lesions and normal appearing white matter
Authors: Khormi Ibrahim , Al-iedani Oun , Casagranda Stefano , Papageorgakis Christos , Alshehri Abdulaziz , Lea Rodney , Liebig Patrick , Ramadan Saadallah , Lechner-Scott Jeannette
Published: November 2024

Motivation: Monitoring disease progression in people with relapsing-remitting multiple sclerosis (pw-RRMS) presents a substantial clinical challenge. Conventional MRI often fails to provide molecular biomarkers for pathophysiological changes like myelin protein accumulation indicative of demyelination. Goal(s): The study aimed to validate whether amide proton transfer weighted (APTw) imaging could be a sensitive molecular marker for detecting demyelination in MS lesions. Approach: We conducted APTw imaging at 3T on 24 pw-RRMS, evaluating the signal intensity within MS lesions compared to contralateral normal-appearing white matter (cNAWM) regions. Results: The investigation revealed a statistically significant increase in APTw signal intensity in MS lesions compared to cNAWM regions. Impact: Elevated APTw signal intensity could serve as a non-invasive molecular biomarker for demyelination, potentially aiding in the more accurate monitoring of MS disease progression and treatment efficacy.
Exploration of a low-SAR ihMT-RAGE approach for human whole brain imaging at 7T
Authors: Anderson Timothy , Soustelle Lucas , Troalen Thomas , Varma Gopal , Kornaropoulos Evgenios , Guye Maxime , Ranjeva Jean-Philippe , Alsop David , Duhamel Guillaume , Girard Olivier
Published: November 2024

Motivation: Inhomogeneous Magnetization Transfer (ihMT) is a recent MRI technique that has raised great interest for myelin imaging. Several ihMT protocols have been proposed for whole brain imaging at clinical field strengths. However, ultra-high field (UHF, 7T) translation remains challenging. Goal(s): ln this work we explore ways to perform ihMT at UHF for clinical applications. Approach: A low-SAR ihMT-RAGE sequence is proposed by shortening the ihMT preparation and enabling partial Fourier MT saturation. Results: This original sequence addresses SAR limitations within relatively short scan times, allowing for whole brain 1.2mm isotropic resolution (resp. 1mm) in 12 minutes (resp. 16 min) at 7T. Impact: Ultra-high field ihMT enables high resolution (1mm iso) myelin specific imaging, opening new perspectives for neuroscience and clinical research. Future developments, such as reduced FOV and compressed sensing sequences could bring scan times further down to 5-10 minutes.
Refinement of the model and types of data for quantitative Magnetization Transfer (qMT) in brain tissues
Authors: Varma Gopal , Grant Aaron , Soustelle Lucas , Girard Olivier , Duhamel Guillaume , Alsop David
Published: November 2024

Motivation: To improve the accuracy of quantitative Magnetization Transfer (qMT) for interrogation of brain microstructure. Goal(s): To determine: i) the model for qMT that best describes the signal from MT and inhomogeneous MT (ihMT) experiments, and ii) the MT preparations that contribute useful data. Approach: We tested accuracies of the models based on fit quality in-vivo and ex-vivo, comparing ex-vivo qMT at physiological and room temperatures. Data were retrospectively reduced to test the importance of types of MT preparations. Results: We recommend a model with two bound-pool T2 values and use of different MT pulse widths and duty cycles as a result. Impact: Our results will impact the model and data acquired for quantitative Magnetization Transfer (qMT) of brain tissues. Use of a two bound-pool model with distinct T2 values and data inputs with variations in MT pulse width and DC is recommended.
Multilevel clinical connectome fingerprinting: uncovering functional connectivity changes across the migraine cycle
Authors: Esteves Inês , Fouto Ana R. , Ruiz-Tagle Amparo , Caetano Gina , Nunes Rita G. , Silva Nuno A. , Vilela Pedro , Gil-Gouveia Raquel , Martins Isabel Pavão , Caballero-Gaudes César , Figueiredo Patrícia
Published: November 2024

Motivation: Case-control fMRI studies spanning the entire migraine cycle are lacking, precluding a complete assessment of brain functional connectivity in migraine. Such studies are essential for understanding the inherent changes in the brain of migraine patients as well as transient changes along the cycle. Goal(s): Our goal was to determine the influence of the migraine cycle on individual functional connectome fingerprints. Approach: Functional connectivity (FC) was longitudinally studied for migraine patients (across the four different cycle phases) and matched healthy controls. Results: We observed greater heterogeneity in FC patterns of migraine patients and significant changes in FC across the cycle compared to controls. Impact: This work represents the first case-control fMRI longitudinal study across the whole migraine cycle. Building upon clinical connectome fingerprinting, applied for the first time to migraine, it tackles a major cause of disability worldwide, contributing to developing connectome-based disease biomarkers.
Estimating microscopy-informed fibre orientations from in-vivo dMRI using a domain adaptation adversarial network
Authors: Zhu Silei , Dinsdale Nicola , Jbabdi Saad , Miller* Karla , Howard* Amy
Published: November 2024

Motivation: Joint modelling of diffusion MRI and microscopy can leverage their complementary strengths to improve the estimation of fibre orientations. Ideally, these benefits would extend beyond the few datasets where dMRI and microscopy are acquired in the same brain to improve orientation estimates in in-vivo data. Goal(s): To translate the unique properties of joint dMRI-microscopy data modelling to benefit in-vivo dMRI datasets. Approach: We construct a domain adaptation adversarial network that can estimate microscopy-informed FODs from single-shell in-vivo dMRI. Results: Tractography performed using network-derived FODs show improved tracking in grey matter, bottleneck regions, superficial white matter fibres, and long-range structural connectivity. Impact: Our microscopy-informed neural network improves fibre orientation estimation from in-vivo single-shell dMRI datasets. We demonstrate improvements in fibre tracking that may enable more precise and detailed detection of connectivity, with a broad range of applications in basic and clinical neuroscience.
Motion-insensitive heavily T2-weighted phase-based imaging using readout alternation technique
Authors: Tamada Daiki , Kennedy Tabassum , Reeder Scott
Published: November 2024

Motivation: Heavily T2-weighted (T2W) imaging plays a central role in many fluid-sensitive applications. Drawbacks of T2W conventional methods include relatively long acquisition times and motion sensitivity. Goal(s): The goal of this study is to evaluate the feasibility of a novel approach using Heavily T2weighted Phase-Based (HT2WPB) imaging with readout alternation (ROA) to achieve motion-insensitive imaging. Approach: Phantom and in vivo experiments where used to demonstrate the feasibility of heavily T2W using HT2WPB with ROA. Results: Results from this work showed that PBT2W with ROA enabled heavily T2-weighted contrast for improved visibility of fluid containing anatomical structures with reduced motion sensitivity. Impact: The use of heavily T2-weighted phase-based imaging with ROA in MR imaging is a promising method to improve visibility of fluid-containing anatomical structures. This technique has the potential to enhance diagnostic accuracy for the evaluation of various pathologies.
Automated Sequence Design using Neural Architecture Search: Reliability and Reproducibility
Authors: Hong Rokgi , An Hongjun , Ji Sooyeon , Lee Jongho
Published: November 2024

Motivation: An automated sequence design framework utilizing neural architecture search was proposed, and successfully designed optimal sequences for given properties and target objectives without any prior knowledge of MR physics. Goal(s): We aimed to explore the reliability and reproducibility of this method. Approach: The reliability of the method was evaluated by adjusting the weights of the desired objectives for sequence design. The reproducibility was tested through multiple runs of the design process. Results: Our method exhibited reasonable reliability within a certain range of loss weights. Also, it demonstrated reasonable reproducibility in designing SE sequences; however, it exhibited less robustness when designing IR sequences. Impact: Our previous work, an automated sequence design framework utilizing neural architecture search, is further explored. Our methodology successfully designed sequences with reasonable reliability and reproducibility, despite designing without prior knowledge of MR physics.
A Quantitative and Non-Invasive MR-based Method to Analyze Ventricular Shunt Flow in Patients with Hydrocephalus
Authors: Ha Joseph , Borzage Matthew , Doyle Eamon , Gutierrez Madison , Al-Husseini Jacob , Drastal Meghan , Torres Isabel , McComb J. , Blüml Stefan , Chiarelli Peter
Published: November 2024

Motivation: We investigate a new approach to evaluating ventricular shunt function using phase-contrast magnetic resonance imaging (PC-MRI). Goal(s): Our goal was to demonstrate the rapid (96-second) sequence as a practical adjunct for determining shunt function non-invasively. Approach: An MRI phantom was constructed to assess CSF flows between 0-24 cc/hr while in vivo studies measured 21 consecutive patients. Results: The PC-MRI calibration curve demonstrates a slightly non-linear relationship between flow output by pump and PC-MRI measured velocity. The in vivo patient studies flows ranged between 7 and 54 cc/hr. Impact: Our work shows that PC-MRI is a non-invasive method for the measurement of CSF flow through the shunt in patients with hydrocephalus. Our work shows that PC-MRI is a promising addition to the clinical setting.
Prospective Determination of Tumor Regression Grade with Magnetic Resonance Imaging in Neoadjuvant Chemotherapy for Rectal Adenocarcinoma
Authors: Shen Yu , Gong Xiaoling , Qiu Meng , Meng Wenjian , Wang Ziqiang
Published: November 2024

Motivation: The role of MRI in evaluating the tumor response following neoadjuvant chemotherapy (NCT) in rectal cancers remains pending. Goal(s): To investigate the reliability of MRI in assessing the pathological clinical response (pCR) in rectal cancer patients with NCT. Approach: In two consecutive prospective clinical trials (Clinicaltrials.gov NCT03666442 and NCT04922853), tumor responses to NCT were evaluated using MRI-based models. Results: 224 patients were enrolled. MR-TRG, DWI, DWImodMR-TRG mriCR, and rNAR score were all associated with pCR. DWImodMR-TRG achieved the highest area under the curve (AUC) of 0.940, with the highest sensitivity of 0.905 and the highest PPV of 0.976. Impact: MRI-based models were feasible in determining the tumor response in LARC patients following NCT. DWI may improve the predictive performance of MR-TRG. Our findings provide evidence for the determination of tumor response for rectal cancer patients who underwent NCT.
Single-click joint bright- and black-blood late gadolinium enhancement and T1-rho mapping for improved myocardial scar imaging
Authors: de Villedon de Naide Victor , Stuber Matthias , Zhang Jana Huiyue , Villegas-Martinez Manuel , Brillet Nina , Narceau Kalvin , Gut Pauline , Nogues Victor , Benlala Ilyes , Cochet Hubert , Bustin Aurélien
Published: November 2024

Motivation: Bright-blood sequences are used to retrieve information about cardiac anatomy and function, while black-blood sequences have been exploited for focal scar detection. Moreover, contrast agent-free T1-rho (T1ρ) mapping has shown promise for scar quantification, particularly of diffuse nature. Goal(s): We propose SPOT1ρ, a single-click joint bright-blood, black-blood, and T1ρ mapping sequence providing improved scar localization, detection, and quantification. Approach: The proposed SPOT1ρ was compared to reference sequences in phantom and patients (three myocardial infarctions, one cardiac amyloidosis and one healthy control). Results: Excellent correlation was observed between SPOT1ρ and reference T1ρ values, along with co-registered bright- and black-blood images in phantom and patients. Impact: The proposed single-click SPOT1ρ permits easier and faster planning for MR technicians, more comfort for the patient, promoted by fewer breath-holds, and a simplified interpretation for the radiologists, through co-registered, qualitative, and quantitative images.
3D Isotropic Wideband LGE for Supporting Ventricular Tachycardia Ablation in Patients with an Implantable Cardioverter Defibrillator
Authors: Hong KyungPyo , Lee Daniel , Sarnari Roberto , Avery Ryan , Collins Jeremy , Patel Amit , Khoshknab Mirmilad , Nazarian Saman , Lin Albert , Knight Bradley , Kim Daniel
Published: November 2024

Motivation: Catheter ablation is clinically indicated for targeting re-entrant ventricular tachycardia (VT) in patients with an implantable cardioverter defibrillator (ICD), but its 1-year VT recurrence rate is high. We hypothesize that 3D wideband LGE is useful for guiding VT ablation. Goal(s): To determine whether 3D wideband LGE correlates with electroanatomic mapping (EAM) in ICD patients. Approach: To develop a 3D isotropic wideband LGE pulse sequence and validate it against EAM in ICD patients. Results: While myocardial scars and gray-zones in LGE correlated with the low voltage areas (<1.5 mV) in EAM, mid-myocardial non-ischemic scars was not correlated between LGE and EAM. Impact: High-resolution 3D isotropic wideband LGE has potential to increase the success rate of catheter ablation for re-entrant ventricular tachycardia in patients with an implantable cardioverter defibrillation, as well as decrease the procedural time by providing a roadmap prior to ablation.
Accelerated Method for Joint Fatty Acid Composition and T1 (FACT) Mapping of Epicardial Adipose Tissue in Mice at 9.4 T
Authors: Bresticker Julia , Echols John , Epstein Frederick
Published: November 2024

Motivation: Proinflammatory epicardial adipose tissue (EAT) contributes to heart failure (HF). MRI fatty acid composition (FAC) and T1 of EAT may distinguish proinflammatory vs. healthy EAT. Applying separate FAC and T1 mapping sequences is time consuming, motivating the development of accelerated methods. Goal(s): Our goal was to create an accelerated joint EAT FAC and T1-mapping method (FACT) for use in mice at 9.4 T. Approach: An inversion-recovery multi-echo sequence and model-based mapping method was developed with acceleration along orthogonal time dimensions. Results: Results demonstrate feasibility of the FACT method with approximately rate 12 acceleration. Impact: The FACT method efficiently and accurately determines both EAT fat composition and T1 and could be used in-vivo to investigate mechanisms and efficacy of novel therapies targeting proinflammatory EAT in the context of metabolic heart disease.
Protective Effects of High-Altitude Hypobaric Hypoxia on Myocardial Infarction: A 7.0T Cardiovascular Magnetic Resonance Study in a Rat Model
Authors: Fang Xin , Gao Fabao
Published: November 2024

Motivation: The impact of high-altitude hypobaric hypoxia on myocardial infarction cardioprotection is a subject of ongoing research in cardiovascular studies. Goal(s): We aimed to assess the potential protective effects of high-altitude hypobaric hypoxia in a rat model of MI using 7.0T CMR strain analysis. Approach: We used rats model and transporting some rats to an elevation of 4,250 meters, while control rats remained at 500 meters. Then surgically induced myocardial infarctions in the rats at each elevation. Results: The finding was that rats with MI living at high altitude had significantly better preservation of heart function compared to control rats living at 500 meters. Impact: The outcomes of this study hold significance for the management of patients at risk of MI, particularly those residing in high-altitude environments or experiencing hypobaric hypoxia. Identifying the cardioprotective effects may result in the development of new therapeutic strategies.
Protocol-aware unsupervised retrospective T1 and T2 mapping with diverse imaging parameters
Authors: Qiu Shihan , Xie Yibin , Christodoulou Anthony , Sati Pascal , Maya Marcel , Sicotte Nancy , Li Debiao
Published: November 2024

Motivation: Quantitative MRI has the potential for improved disease characterization, but the limited accessibility impedes its application. Goal(s): To develop a deep learning method for retrospective T1 and T2 quantification from real-world brain MRI data, with the ability to handle diverse imaging protocols. Approach: A protocol-aware self-supervised learning framework was developed, with the imaging parameters incorporated as additional inputs to the model. Results: Validation on volunteers showed errors within 10% for nine brain regions when compared to prospective T1/T2 mapping. Application to 376 glioblastoma patients with diverse imaging protocols revealed statistical differences in T1 and T2 among tumor sub-regions and normal-appearing tissues. Impact: The proposed method may allow retrospective T1 and T2 mapping in large real-world MRI datasets, enabling analysis of them regardless of the difference in protocols and scanners. This will facilitate the large-scale investigation of quantitative MRI as biomarkers for diseases.
Contrast neutralization as a strategy to achieve generalizability in MR deep learning applications
Authors: Bhushan Chitresh , Singhal Vanika , Shanbhag Dattesh
Published: November 2024

Motivation: Provide flexibility to clinicians to fine-tune protocols/contrasts while still leveraging existing Deep-learning (DL) applications trained with limited set of MR contrasts. Goal(s): Develop task-specific contrast neutralization pre-processing step to handle multiple imaging contrasts, that are different from the contrasts in the trainset. Approach: Investigate Simple Contrast Neutralization (SCNe) approach that leverages Fourier domain filtering to neutralize contrast from objects of desired sizes, and demonstrate its impact on generalization of cervical foramina plane determination. Results: Statistically significant improvements in prediction of planes when SCNe is used on new MERGE T2* contrast with DL-model that was trained only with Ax-T2 images. Impact: Use of our Simple Contrast Neutralization (SCNe) approach as pre-processing step was effective in making DL-model trained only with Ax-T2 images robust to unseen new contrast MERGE T2* MR dataset for Spine cervical foramina (CF) plane determination.
BlindHarmony: Blind harmonization for multi-site MR image processing via unconditional flow model
Authors: Jeong Hwihun , Byun Heejoon , Lee Jongho
Published: November 2024

Motivation: Conventional deep learning-based harmonization cannot handle the unseen source domain image when there is no large-size data. Goal(s): We propose blind harmonization, which requires only target domain data during training and generalizes well on unseen source domain data. Approach: BlindHarmony utilizes an unconditional flow model to measure the probability of the target domain image and find a harmonized image that is structurally close to this source domain image but has a high probability in the target domain. Results: BlindHarmony successfully harmonized the source domain image to the target domain and improved the performance of downstream tasks for the data with a domain gap. Impact: Deep learning-based harmonization typically necessitates both source and target domain data, limiting its widespread applicability. This study eliminates the need for source domain data and exhibits robust generalization to new source domain data, thereby expanding the utility of harmonization.
Assessing Machine Learning Robustness in MRS Quantification: Impact of Training Strategies on Out-of-Distribution Generalization
Authors: Merkofer Julian , Kaiser Antonia , Schrantee Anouk , Gurney-Champion Oliver , van Sloun Ruud
Published: November 2024

Motivation: Despite promising developments, current machine learning methods for magnetic resonance spectroscopy (MRS) suffer from limited robustness and generalization issues, restricting their clinical application. Goal(s): This study compares training strategies for MRS quantification, focusing on neural network resilience to out-of-distribution samples. Approach: Bias towards the training distribution was assessed for various out-of-distribution cases in synthetic data and in-vivo data. Results: Our findings reveal that, while common supervised regression is most accurate for in-distribution cases, it shows the most data bias; physics-informed self-supervised training is more robust; while integrating a least-squares fitting method within the training framework enhances standalone performance while remaining generalizable. Impact: To advance integration in clinical MRS, robust and generalizable machine learning methods are needed. This study's exploration of quantification training strategies offers insights into data biases and advocates hybrid models that combine traditional methods with neural networks to maintain robustness.
Temperature Changes in the Brain due to External Heat Sources: an MR Thermometry Study
Authors: Kikken Mathijs , Steensma Bart , Meliadò Ettore , van den Berg Cornelis , Raaijmakers Alexander
Published: November 2024

Motivation: RF-induced temperature rise is considered a safety risk for MRI. Goal(s): To study temperature changes in the brain due to (generally considered safe) heat or cool pads placed on a subject's forehead for comparison to RF-induced temperature elevations. Approach: Using the Projection onto Dipole Fields method, susceptibility and drift induced field changes are separated from temperature effects to enable assessment of temperature rise in the brain. Results: Up to 2.5 °C temperature rise was measured at the brain edge in 2 volunteers. Similarly, a 2.0 °C decrease was observed at the brain edge when a coolpad was placed on the forehead. Impact: RF-induced temperature changes in the brain can be considered modest compared to temperatures induced by (generally considered safe) external heating/cooling sources. The temperature increase due to a heatpad on the forehead is much larger than previously measured RF-induced temperature increases.
Two distinct thalamic subtypes associated with cognitive impairment in first-episode schizophrenia
Authors: Yu Wei , Tao Bo , Zhao Qiannan , Xiao Yuan , Zhu Fei , Gao Ziyang , Lui Su
Published: November 2024

Motivation: Schizophrenia is characterized by high heterogeneity, with the core symptom of cognitive impairment. However, it is unclear that whether the patterns of thalamic nuclei volume alterations is associated with cognitive function in schizophrenia. Goal(s): To investigate the pattern and heterogeneity of thalamic nuclei alterations and cognition in schizophrenia. Approach: The cluster analysis (K-means++) was used to identify the subtype of schizophrenia. And machine learning model was developed to validate the reproducibility of subtypes. Results: We uncovered two markedly distinct neuroanatomical subtypes of schizophrenia. One of the subtypes characterized as widespread decrease in thalamic nuclei and severe cognition deficit. Impact: These findings could help to identify biological targets related to the treatment of schizophrenia, and improve the functional outcomes in patients with schizophrenia.
Double Inversion Recovery in myocardial Arterial Spin Labeling (ASL) for reduced physiological noise
Authors: Božić-Iven Maša , Zhang Yi , Tao Qian , Rapacchi Stanislas , Schad Lothar , Weingärtner Sebastian
Published: November 2024

Motivation: Myocardial Arterial Spin Labeling (myoASL) presents a promising contrast-agent-free approach for assessing myocardial blood flow (MBF), but its clinical translation is hampered by high levels of physiological noise (PN). Goal(s): We introduce double inversion recovery (DIR) preparations for FAIR-myoASL to mitigate sensitivity to heart rate variations and reduce PN. Approach: A flip-back inversion pulse was added immediately after the FAIR-labeling, to allow for near-complete recovery and, thus, for more effective cancellation of the myocardial background signal in the presence of heart rate variations. Results: Using DIR preparations in vivo, led to a PN reduction of up to 66 % compared to conventional myoASL. Impact: FAIR-myoASL with double inversion recovery (DIR) labeling can compensate for fluctuating myocardial background signals due to heart rate variability. In vivo, experiments suggest that DIR-preparations substantially reduce PN, thus, improving overall robustness and potentially facilitating broader clinical translation of myoASL.
Optimization of Echo Time for BOLD Dynamic Susceptibility Contrast MRI
Authors: LE THUY THI , CHOI SANG HAN , LEE CHAN HEE , IM GEUN HO , KIM SEONG-GI
Published: November 2024

Motivation: Achieving accurate quantification of absolute CBV and CBF in BOLD-DSC depends on maximizing the hypoxia-induced signal changes and accurately determining the arterial input function. Goal(s): The choice of echo time affects both baseline signal-to-noise ratio and hypoxia-induced changes1,2, our study aimed to investigate the effects of different TEs on the quantification of CBV and CBF. Approach: We systematically varied TE within the range of 11.57 ms to 20 ms , measured hypoxia-induced signal changes in arterial, venous, and somatosensory tissue voxels, and quantified perfusion metrics. Results: We discovered that a shorter TE, which produces sufficient signal changes without causing arterial peak saturation, is preferable. Impact: Shorter TE leads to less hypoxia-induced signal changes, while longer TE decreases baseline SNR and increase the risk of arterial signal saturation. This signal saturation leads to the underestimation of AIF, and consequently, overestimation of perfusion quantification.
UTE-Based DW-SSFP MRI for 7T
Authors: Jung Kwan-Jin
Published: November 2024

Motivation: At 7T the conventional spin-echo EPI diffusion sequence suffers from the B1+ inhomogeneity and geometric distortion due to refocusing RF pulses and EPI readout. Goal(s): To develop a diffusion imaging sequence without refocusing RF pulses and EPI readout at 7T. Approach: Develop a 3-dimensional DW-SSFP sequence with a spiral readout to reduce the geometric distortion, to maximize the diffusion gradient time, and to reduce susceptibility effect. Results: The proposed DW-SSFP sequence was successful in reducing the B1+ inhomogeneity, the geometric distortion, and the susceptibility effect compared to the spin-echo EPI diffusion sequence using cadaveric head specimens at 7T. Impact: This sequence enables the acquisition of high-resolution diffusion images that do not suffer from the B1+ inhomogeneity and geometric distortion often observed at 7T. It provides good quality fiber tracts and fractional anisotropy maps of the brain.
High-resolution whole brain multi-shell diffusion MRI at 5.0 Tesla
Authors: Liu Fan , Shi Diwei , Shao Xin , Li Sisi , Tian Qiyuan , Guo Hua
Published: November 2024

Motivation: In neuroscientific researches, 3T DWI provides limited resolution while 7T DWI suffers from challenges such as shorter relaxation time and increased field inhomogeneity. Goal(s): To evaluate the performance of 5T in high-resolution whole brain multi-shell DWI. Approach: 1.1 mm-isotropic whole brain DWI with 2 shells was acquired using multi-band single-shot 2D EPI on 5T. DTI metrics and MSMT-CSD model were computed. The nearly identical acquisition parameters and data processing were applied to the same subject on 3T. Results: 5T DWI resolved brain structural connectivity more accurately than 3T. Better FA contrast was observed at 5T, demonstrating higher SNR achieved at 5T. Impact: The feasibility of simultaneously achieving high spatial resolution and adequate q-space sampling in practical acquisition time at 5T demonstrated its potential as a new tool in DWI-based neuroscientific studies.
MR Thermometry with High Precision and Temporal Resolution by Quadratic Phase MR Fingerprinting
Authors: Garrow Sarah , Boyacioglu Rasim , Keenan Kathryn , Griswold Mark , Grissom William
Published: November 2024

Motivation: Proton resonance frequency (PRF)-shift thermometry is the current standard for MR-temperature monitoring in interventional procedures. However, the long TE required for phase contrast induces signal dropout and increases sensitivity to metal and motion artifacts. Goal(s): Use quadratic RF phase (qRF) MR fingerprinting to image off-resonance frequency for thermometry at a real time frame rate. Approach: Because PRF change is much more sensitive to temperature change in aqueous tissue than T1/T2, we propose a “lightweight” constant low-flip-angle MRF sequence optimized for 3s or less frame rate to measure temperature from the PRF shift. Results: We implemented qRF-MRF thermometry with high spatiotemporal resolution. Impact: A thermometry method with high temporal resolution that does not suffer from signal dropout at high temperatures can enable more accurate temperature monitoring for MR-guided interventional procedures. Additionally, it has potential to be more robust to motion artifacts.
EPTIMA: Echo Planar Time-resolved Imaging derived Millisecond-scale temporal resolution Acquisition
Authors: Dong Zijing , Sohrabpour Abbas , Wald Lawrence , Polimeni Jonathan , Sundaram Padmavathi , Wang Fuyixue
Published: November 2024

Motivation: Achieving millisecond-scale temporal resolution MRI has the potential to provide exciting insights into fast functional/physiological processes of the brain. Goal(s): Develop a new acquisition method, EPTIMA, that can achieve millisecond-scale temporal resolution, while improving efficiency by acquiring a time-series trial of 2D-images in a single excitation for high robustness to physiological-noise/motion. Approach: EPTIMA captures fast temporal dynamics occurring within the readout by measuring the rate at which the baseline signal evolution is changing, and employs spatiotemporal encodings to acquire a complete time-series trial in a single-excitation. Results: EPTIMA can image rapid electric current changes in a phantom and resolve stable phase/magnitude changes in-vivo. Impact: A new acquisition, EPTIMA, was developed to achieve millisecond-scale temporal resolution and to image ultra-fast dynamic processes of human brain. It improves efficiency by acquiring a time-series trial of 2D-images in a single excitation with high robustness to motion/physiological noises.
Simultaneous two-voxel functional magnetic resonance spectroscopy of the motor cortex at 7T
Authors: Schrantee Anouk , Berrington Adam
Published: November 2024

Motivation: Functional magnetic resonance spectroscopy (fMRS) shows promise in studying task-related metabolite changes but has been largely confined to single-voxel. Goal(s): To evaluate two-voxel fMRS at 7 T to measure simultaneous bilateral metabolite changes during a unilateral motor task. Approach: A modified Hadamard-encoded MRS scheme with dynamic fMRS spectral-temporal fitting for analysis was employed. Results: Distinct patterns of BOLD activation in contra- and ipsilateral VOIs were detected with significant increases in Glutamate (Glu) in either VOI during a unilateral taskImpact: We demonstrate the feasibility of simultaneous two-voxel MRS to detect bilateral glutamate changes in response to a unilateral motor task. This approach holds promise to increase our understanding of the neurochemical underpinnings of fMRI signals across interconnected brain regions.
Bumetanide drug effect on the transmembrane water exchange by T1 relaxation at ultra-low field
Authors: El Atifi Michele , Berger François , Lahrech Hana
Published: November 2024

Motivation: The transmembrane water exchange (t-Wex) in cancers was demonstrated modulating T1 relaxation at ultra-low field. Goal(s): Our goal was to demonstrate T1 changes under the administration of drugs that act on cell membrane transports. Approach: U87 glioma cells sustained H2O2 stimuli before the administration of the bumetanide drug, a NKCC1 inhibitor. T1 changes were measured by FFC-NMR. Results: At very low field, by comparison to control cells (without H2O2), relaxation rates were found significantly lower under H2O2 stimuli which has been correlated to t-Wex acceleration and higher with the bumetanide addition, that suggests the slowdown of t-Wex. Impact: Using the bumetanide drug, we show at ultra-low field, the potential of the relaxation T1 as biomarker to evaluate the efficiency of drugs that can target t-Wex, a mechanism that has been connected to cancer invasion/migration pathophysiology
Multiparametric Characterization of Focal Cortical Dysplasia Using Three-Dimensional MR Fingerprinting
Authors: Su Ting-Yu , Choi Joon Yul , Hu Siyuan , Wang Xiaofeng , Blümcke Ingmar , Chiprean Katherine , Krishnan Balu , Ding Zheng , Sakaie Ken , Murakami Hiroatsu , Najm Imad , Jones Stephen , Ma Dan , Wang Zhong Irene
Published: November 2024

Motivation: Focal cortical dysplasia (FCD) is a common pathology in medically intractable focal epilepsy. Detecting and subtyping FCD through visual inspection of conventional MRI can be challenging. Goal(s): We aimed to develop a multiparametric, quantitative approach for FCD characterization, based on MR fingerprinting (MRF). Approach: High-resolution 3D MRF scans were performed in 33 epilepsy patients with FCD, 60 normal controls and 26 disease controls. A machine-learning (ML) framework based on MRF was developed to automatically classify FCD from normal cortex and separating FCD subtypes. Results: MRF-based ML models showed high accuracies, with performances superior to the yields of clinical review. Impact: Our approach contributes to noninvasive epilepsy presurgical evaluation, as well as an integrated clinical-pathological-imaging understanding of the FCD spectrum.
Comparison of multiple sclerosis and neuromyelitis optica spectrum disorder: A physiological and quantitative MRI study
Authors: Yu Shuwan , Lin Zixuan , Han Hualu , Xu Ning , Liu Jiachen , Tong Xinyu , Qiao Huiyu , Ning Zihan , Shen Rui , Zhao Mangsuo , Zhao Xihai
Published: November 2024

Motivation: Accurate differentiation of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is essential for treatment decisions and thus affects prognosis. Goal(s): This study aimed to determine the differences of MS and NMOSD using physiological and quantitative MRI. Approach: blood brain barrier permeability to water (PS) and oxygen extraction fraction (OEF) of all subjects were measured by physiological and quantitative MRI. Results: The results showed that compared with healthy subjects, water PS was significantly higher in NMOSD patients, while OEF was significantly lower in MS patients. In addition, OEF was also significantly different between NMOSD patients and MS patients. Impact: Our study demonstrated that BBB permeability to water and whole-brain oxygen extraction fraction (OEF) might be potential imaging indicators for NMOSD and MS, respectively. In addition, OEF is the key to distinguish MS from NMOSD.
Blood-brain barrier breakdown in Alzheimer's disease and dementia with Lewy Bodies based on water exchange DCE-MRI
Authors: Xu Ziming , Dou Jiaqi , Gan Jinghuan , Chen Zhichao , Wang Yajie , Ji Yong , Chen Huijun
Published: November 2024

Motivation: Transfer rate of contrast agent and water plays complementary role in assessing the integrity of blood-brain barrier, however there is currently no means of evaluating them simultaneously in dementia patients. Goal(s): We aimed to develop a new pharmacokinetic model to comprehensively evaluate the blood-brain barrier damage in dementia patients. Approach: Transfer rate of contrast agent and water was calculated based on a new pharmacokinetic model by simultaneous fitting of the Bloch–McConnell equation and the Patlak model. Results: The proposed model was able to exhibit distinct patterns of blood-brain barrier damage in different types of dementia, which was significantly associated with cognitive impairment. Impact: The transfer rate of contrast agent and water based on water exchange DCE-MRI demonstrated distinct patterns of blood-brain barrier damage in patients with Alzheimer’s disease and dementia with Lewy bodies, providing promising new non-invasive imaging biomarkers for dementia.
Robust Estimation of Venous Cerebral Blood Volume Using Flow-Diffusion Modeling Combined with R2' and Perfusion Measurements
Authors: Zappalà Stefano , Patitucci Eleonora , Driver Ian , Küppers Fabian , Yun Seong , Shah Jon , Wise Richard , Germuska Michael
Published: November 2024

Motivation: Factoring out venous cerebral blood volume (vCBV) and oxygen extraction fraction (OEF) from the relaxation of R2’ poses a significant challenge. Goal(s): We combined robust measurements of R2’ relaxation from GE-SE EPIK and perfusion from VSI-ASL with a flow-diffusion model of oxygen transport to improve estimation of vCBV and OEF. Approach: The proposed method was tested in normoxia, hyperoxia and hypercapnia against validated TRUST measurements of OEF. Results: Maps of OEF and vCBV accurately depicted the oxygen metabolism at baseline as well as during the gas challenges without the need of any calibration, with high resolution and within reasonable acquisition time. Impact: The integration of the oxygen flow-diffusion model with GE-SE EPIK measurements of R2’ relaxation and VSI-ASL measurements of perfusion gives high resolution parametric maps of oxygen metabolism within reasonable acquisition time, ultimately reducing the gap between research and clinical practise.
Contrast-free Blood Volume, Microvascular Properties and Relaxometry mapping using bSSFP MR Fingerprinting
Authors: Coudert Thomas , Delphin Aurélien , Legris Loïc , Barrier Antoine , Warnking Jan , Chechin David , Lamalle Laurent , Mazurkewitz Peter , Koken Peter , Barbier Emmanuel , Doneva Mariya , Christen Thomas
Published: November 2024

Motivation: Most MR methods for quantifying microvascular properties involve the injection of exogenous contrast agents (CA). Goal(s): We propose an innovative MRI method that simultaneously maps the deoxygenated cerebral blood volume (CBV), microvascular geometry (averaged vessel radius), and relaxometry (T1&T2) without CA injection. Approach: Acquisitions are made using a multi-echo, phase-cycled, bSSFP-sequence acquired in transient and pseudo-steady-state regimes. Reconstruction of the maps is made under the MRFingerprinting framework using realistic 3D microvessel representations. Magnetic field distributions (B1&B0) are also taken into account. Results: Preliminary results on five healthy volunteers are in line with previous measurements made with MRF and PWI with gadolinium injection. Impact: We propose a contrast-free quantification technique of microvascular properties and relaxation times. It could be useful for functional experiments as well as clinical investigations of several cerebrovascular pathologies including stroke and cancer.
Brain structure and glucose metabolism in juvenile and adult-onset Huntington disease: a cross-sectional and longitudinal PET/MR study
Authors: Caligiuri Maria Eugenia , Bonacci Maria Celeste , Cascini Giuseppe Lucio , Quattrone Aldo , Squitieri Ferdinando , Sabatini Umberto
Published: November 2024

Motivation: Juvenile-onset Huntington Disease (JoHD) represents 4-10% of HD cases, has worse prognosis and psychiatric rather than motor symptomatology, compared to the adult form (AoHD). No study has yet investigated morphological and metabolic changes comparing these two forms with PET-MRI. Goal(s): Are brain structural and metabolic changes different between patients with JoHD and AoHD? Do they evolve differently?Approach: PET/MRI was acquired on AoHD and JoHD patients. Cortical and subcortical hybrid characteristics were compared between groups and overtime. Results: POHD had the most remarkable striatum volume loss at baseline. Interestingly, POHD brain cortex volume was relatively spared at baseline if compared to AOHD patients. Impact: This study provides first evidence that disease-related degeneration in JoHD first affects subcortical regions, where atrophy is more severe compared to AoHD, and ultimately spreads to the cortex, with faster rates of thinning and glucose metabolism changes compared AoHD.
Implementation of an Optical System for Signal and Power Transmission in Light Coils
Authors: Liu Zining , Yin Nan , Ataman Çağlar , Helmers Henning , Bock Michael , Özen Ali
Published: November 2024

Motivation: RF-induced heating and reduced image signal-to-noise ratio (SNR) due to crosstalk between adjacent cables are problematic in dense receive arrays. RF coils with fiber-optical connection can overcome these problems associated with metallic wires. Goal(s): To develop optical signal and power transmission units for MRI. Approach: An analog photonic link with Mach-Zehnder modulator was constructed for optical signal transmission, and GaAs-based photonic power converters were used for power-over-fiber supply of low-noise-amplifiers (LNA). Results: Image SNR and signal dynamic range of the photonic link are comparable with coaxial cable connection. Photonic power convertors can supply up to 10 LNAs in the receive chain. Impact: Fully optical signal and power transmission is feasible for RF coils. It enables extremely dense modular receive arrays by eliminating cable-crosstalk and overcoming RF induced heating problems.
Enhanced Leptomeningeal Collateral Visualization in Moyamoya Disease: A 5.0-T 4D NCEMRA Study
Authors: Wang Yining , Zhou Yijun , Zhao Shihai , Yang YuXin , Chen Shuo , Xue Ke , Wang Dong , Li Mingli , Ni Jun , Zhang Dong , Feng Feng
Published: November 2024

Motivation: Moyamoya disease necessitates precise visualization of cerebral vessels for management, but current imaging may be inadequate. Goal(s): To ascertain if 5.0-T 4D NCEMRA offers superior imaging of collateral circulation in Moyamoya disease compared to traditional TOF MRA. Approach: Utilized 5.0-T MRI to compare 4D NCEMRA and TOF MRA in visualizing leptomeningeal collateral anastomoses in 19 patients. Results: 5.0-T 4D NCEMRA outperformed TOF MRA, particularly in identifying leptomeningeal collaterals, with significant statistical support. Impact: The study underscores 5.0-T 4D NCEMRA's potential to enhance cerebral vascular mapping in Moyamoya disease, prompting advancements in diagnostic and therapeutic strategies, possibly leading to more personalized patient care.
Cerebral Blood Flow Pulsatility Predicts the Cerebral Hyperperfusion Syndrome after direct revascularization surgery—A pilot study
Authors: mingfang Luo , Yuting Wang , Zhenyu Wang , Xiao Hu , Yishuang Wang , Bo He
Published: November 2024

Motivation: Little is known about cerebral hemodynamics after bypass surgery in patients with chronic arterial stenosis (CAS) and its role in the development of cerebral hyperperfusion syndrome (CHS). Goal(s): The purpose of this study was to explore the hemodynamic characteristics of patients with CAS and occlusion before and after surgery and its relationship with CHS. Approach: We used 4D flow MRI sequence to obtain the hemodynamic characteristics of patients with CAS and occlusion before and after bypass surgery. Results: Postoperative total cerebral blood flow increased and resistance index and pulsatility index decreased maybe a higher risk factor of CHS events in bypass surgery patients. Impact: This study provides a new insight into the hemodynamic characteristics of patients with chronic arterial stenosis, and holds a promising marker for marker for identifying CHS patients.
High Fidelity Imaging of Tissue Heterogeneity, Micro-Anisotropy and Diffusion-Time Effects in Prostate Cancer
Authors: Molendowska Malwina , Engel Maria , Müller Lars , Lasic Samo , Jones Derek , Tax Chantal , Szczepankiewicz Filip
Published: November 2024

Motivation: Clinical diffusion MRI for prostate cancer diagnosis has limited sensitivity and specificity to heterogenous microstructural changes. Goal(s): Quantify time-dependent diffusion and diffusional variance at a high spatial resolution in human prostate in vivo. Approach: The diffusion encoding waveforms were tailored to probe micro-anisotropy and diffusion time effects at high b-values. Ultra-strong gradients and spiral readout enabled high-resolution and high image fidelity at a high SNR. Results: Significant time-dependent diffusion was observed in all diffusion parameters in three volunteers, including prostate cancer patients. Impact: The proposed methodology enables evaluation of microscopic anisotropy and time-dependent diffusion in the prostate and provides insights into how dMRI should be interpreted at low and high b-values. The produced diffusion parameters may serve as biomarker candidates in future studies.
Revisiting outer volume subtraction with deep-learning tools for highly-accelerated real-time cine CMR
Authors: Gulle Merve , Kellman Peter , Akcakaya Mehmet
Published: November 2024

Motivation: Real-time cine CMR provides a free-breathing ECG-free approach for heart function assessment. Nevertheless, commercially available real-time cine CMR methods without temporal regularization have limited acceleration and spatio-temporal resolutions. Goal(s): Use deep learning (DL) to remove extra-cardiac volume that aliases into the heart and improve acceleration rates for real-time cine CMR using only spatial regularization. Approach: We characterize pseudo-periodic ghosting artifacts arising from cardiac motion in time-interleaved sequences, then use DL to detect and remove them. This is followed by self-supervised physics-driven DL reconstruction. Results: Proposed technique effectively estimates and removes background signal, leading to substantial image quality improvement. Impact: We characterize and use deep learning (DL) to estimate pseudo-periodic ghosting artifacts arising from cardiac motion in time-interleaved real-time cine sequences. Background removal followed by physics-driven DL reconstruction substantially improves reconstruction at nominal R=8 for higher spatio-temporal resolution acquisitions.
Locally Adaptive Low Rank Regularization with Collaborative Data Selection for Arterial Spin Labeling MRI Denoising
Authors: Liu Hangfan , Li Bo , Li Yiran , Detre John , Wang Ze
Published: November 2024

Motivation: Address the challenge of low SNR in arterial spin labeling (ASL) MRI that hinders its clinical and research potential. Goal(s): Develop an advanced ASL denoising algorithm that enhances image quality and overcomes limitations in ASL due to low SNR. Approach: Propose a Locally Adaptive low rank regularization with Collaborative data Selection (LACS) scheme that utilizes the structural characteristics of ASL images for collaborative data selection to improve low-rank modeling. The proposed low-rank regularization fundamentally performs locally adaptive PCA without explicit training. Results: Using a single ASL image pair, LACS significantly outperformed state-of-the-art MRI denoising methods and the standard pipeline. Impact: The proposed scheme has the potential to benefit researchers, clinicians, and patients by setting a new benchmark for ASL MRI denoising. It opens doors to exploring ASL's full clinical potential and offers opportunities for innovative research.
Using water beads as static tissue in a Circle of Willis flow phantom in 4D flow MRI
Authors: El Ahmar Ali , Winter Patrick , König Stephan , Duckert Adrian , Kromrey Marie-Luise , Schnell Susanne
Published: November 2024

Motivation: While previous research has focused on realistic vessel and flow replication, the background tissue mimicking in 4D flow MRI remains unexplored despite its significant impact on phase correction accuracy. Goal(s): Aims to identify a suitable material for a Circle of Willis flow phantom that can mimic background static tissue, ensure transparency, and constrain vessel motion. Approach: Transparent water beads soaked in a Gd-doped solution were used as background static tissue in a flow phantom. A MATLAB tool was used for the post-processing of the 4D-flow data. Results: Water beads effectively minimized motion artifacts, and increased the number of time-averaged streamlines and their quality. Impact: This study introduces a practical solution, to enhance the accuracy of in-vitro 4D Flow MRI of complex vessel phantoms by mitigating motion artifacts. The transparent water beads offer a cost-effective and easily exchangeable alternative for mimicking background static tissue.