bluuebunny/crossref_metadata_2025 huggingface dataset:
IVIM perfusion parameters for non-invasive characterization and radionuclide response assessment in a neuroendocrine tumor model
Authors: Montelius Mikael , Jalnefjord Oscar , Rosenqvist Louise , Forssell-Aronsson Eva , Ljungberg Maria
Published: November 2024

Motivation: IVIM MRI potentially offers non-invasive, non-contrast-based quantification of tumor perfusion parameters, which would facilitate tumor tissue characterization and longitudinal assessment of radionuclide therapy. Goal(s): The goal was to study the feasibility of using IVIM metrics for spatiotemporal tissue characterization in the context of radionuclide therapy in a neuroendocrine tumor model. Approach: Mice with human neuroendocrine tumors were imaged before and repeatedly after radionuclide treatment and parametric maps of perfusion-related parameters from IVIM and DCE were compared and studied longitudinally. Results: Interesting spatiotemporal variations that revealed similarities between techniques show promise for further in-depth analysis using spatial image registration techniques and histopathological validation. Impact: Non-invasive, spatiotemporally resolved tumor perfusion characterization using intravoxel incoherent motion MRI would benefit preclinical optimization and understanding of radionuclide treatment with possible rapid translation into the clinics due to the widespread use of MRI in both research and clinical practice.
Tumour mechanics and vascular fractality quantification via MR-Elastography in the context of liver metastasis from colorectal cancer
Authors: Boumaza Asma , Mangin Gabrielle , Penney Jake , Annio Giacomo , Laouirem Samira , Albuquerque Miguel , Vilgrain Valerie , Paradis Valerie , Sinkus Ralph
Published: November 2024

Motivation: Colorectal cancer is a major global cause of cancer-related deaths, often metastasizing to the liver. Standard treatment includes chemotherapy and anti-angiogenic therapy. Quantifying therapy efficacy remains a clinical challenge. Goal(s): We explore multifrequency MR-Elastography (MRE) for assessing vascular organization, using a murine liver metastasis model correlated with histopathology. Approach: The study used MRE imaging of murin liver metastasis model and the corresponding histopathology to analyze vascular organization (fractal dimension), by measuring Hurst index (H-index). Results: The H-index differs significantly between tumor and healthy liver tissue, with normal vasculature displaying a lower H-index compared to the tumoral tissue. Impact: Our in vivo elastography study demonstrates the organization of the vascular network by matching with histological findings. This innovative approach paves the way for non-invasive evaluation of treatments targeting tumor vessels, such as bevacizumab or FOLFOX.
Amide proton transfer-weighted MRI in predicting tumor budding grade of rectal adenocarcinoma: A prospective pilot study
Authors: Xie Peiyi , Huang Qitong , Zheng Litao , Li Jiao , Meng Xiaochun
Published: November 2024

Motivation: Tumor budding (TB) is an important additional prognostic factor for patients with colorectal cancer (CRC). Goal(s): Accurate TB assessment before surgery can help guide clinical decisions and improve patient prognosis. Approach: This study explored the feasibility of amide proton transfer-weighted (APTw) MR imaging in assessing TB grade in patients with rectal cancer (RC). Results: We found that RC lesions with high-grade TB had higher APTw 90th percentile values than low-grade TB. Impact: APTw MRI may be beneficial for implementing more accurate personalized treatment and improving tumor prognosis.
Dynamic contrast-enhanced gastric MRI features are related to adverse histopathological status in advanced gastric cancer
Authors: Sang Zi-Tong , Hou Ya-Jun , Xu Wei-Yue , Li Qiong , Nickel Dominik , Hsu Yi-Cheng , Liu Xi-Sheng
Published: November 2024

Motivation: Distinct histopathological types are closely related to the prognosis of advanced gastric cancer. Adverse histopathological status (AHS) is linked to poor gastric cancer outcomes. Extra-dimensional volumetric interpolated breath-hold examination (XD-VIBE) offers high temporal and spatial resolution while allowing free breathing. Goal(s): To improve the assessment of AHS, we explored the potential for XD-VIBE to improve DCE imaging. Approach: We evaluated the associations of quantitative DCE MRI parameters (e.g., Ktrans, Ve, and Kep) with AHS. Results: Using XD-VIBE, quantitative DCE MRI parameters allowed non-invasive assessment of AHS and helped to optimize treatment strategies for advanced gastric cancer. Impact: In this single-institution study, quantitative DCE MRI features demonstrated promise as markers of AHS in advanced gastric cancer. These features could provide added prognostic value and identify patients who may benefit from adjuvant therapy.
Correlation of Amide Proton Transfer Magnetic Resonance Imaging with Prognostic Factors in Rectal Adenocarcinoma
Authors: Zhang Caixia , Wang Guanshun , Xu Yongzhou , Yang Yinrui , Liu Lizhu , Li Yanli , You Ruimin , Li Zhenhui
Published: November 2024

Motivation: Improving the accuracy of imaging to assess prognostic factors in rectal adenocarcinoma. Goal(s): Recognizing early rectal adenocarcinoma, assisting clinicians to achieve precision treatment. Approach: Prospective enrollment of rectal adenocarcinoma patients without neoadjuvant therapy undergoing radical surgery for rectal cancer. Using their preoperative imaging data, investigate the correlation between APTw imaging and prognostic factors in rectal adenocarcinoma. Results: APTw SI value are linked to T-stage and the presence of perineural invasion in rectal adenocarcinoma. Impact: This study's results hold promise for the non-invasive identification of nerve invasion in rectal adenocarcinoma, offering a foundation for clinicians to pursue precise treatment strategies.
Added Value of Amide Proton Transfer Weighted MRI in the Evaluation of treatment Response to Neoadjuvant Therapy of Locally Advanced Rectal Cancer
Authors: Zhang Lan , Yang Fan , Sun Peng , Li Xin
Published: November 2024

Motivation: The existing evaluation system remains inadequate for assessing complete response(CR) to neoadjuvant therapy (NAT) for locally advanced rectal cancer (LARC). There is a pressing need for more precise imaging evaluation methods. Goal(s): To investigate the added value of Amide Proton Transfer weighted (APTw) MRI in the evaluation of CR to NAT in patients with LARC. Approach: Diagnosis performance of conventional assessment and APTw-added combined assessment was assessed by receiver operating characteristic curve (ROC) analysis. Results: Diagnostic efficiency in the evaluation of CR was significantly improved when APTw imaging was added to conventional evaluation, with AUC improved from 0.706 to 0.969Impact: Superimposing the advantage of noninvasiveness, APTw imaging may have great application value in solving the clinical problem of diagnosing CR to NAT and provide additional valuable information for clinical decision making.
Reduced Field of View Diffusion MRI for Rectal Cancer Response Assessment after Short Course Radiation and FOLFOXIRI
Authors: Raichandani Surbhi , Pratapneni Aniket , Pollom Erqi , Sheth Vipul
Published: November 2024

Motivation: Rectal cancer response assessment utilizes primarily T2 weighted and diffusion MRI. Reduced field of view diffusion has been shown to have higher imaqe quality and resolution than traditional EPI-based diffusion. Goal(s): We compare reduced field of view diffusion to mrTRG and sigmoidoscopy for assessment of clinical response. Approach: 32 patient MRI were evaluated after treatment with short course radiation (30 Gy, 5 fractions), and FOLFOXIRI and assessed with mrTRG system, ADC on reduced field of view DWI, and sigmoidoscopy. Results: Reduced field of view diffusion is highly accurate for assessment of clinical response nearly matching the performance of mrTRG and surpassing sigmoidoscopy. Impact: Reduced field of view diffusion should be considered for use in clinical protocols assessing rectal cancer treatment response along with T2 weighted MRI and clinical assessment.
Aplastic Anemia in the Adults: Capability of Proton Density Fat Fraction Quantification for Hematopoietic Ability Assessment and Diagnosis
Authors: Ohno Yoshiharu , Sano Yuichiro , Yamamoto Kaori , Shinohara Maiko , Ikedo Masato , Yui Masao , Nagata Hiroyuki , Ueda Takahiro , Nomura Masahiko , Yoshikawa Takeshi , Takenaka Daisuke , Ozawa Yoshiyuki
Published: November 2024

Motivation: PDFF quantification (PD-FFQ) with 6-point Dixon technique has a potential to assess hematopoietic ability assessment and diagnosis of aplastic anemia in adults. Goal(s): The goal was to determine the capability of PD-FFQ with 6-point Dixon technique for diagnosis of aplastic anemia in adults. Approach: Gender and age matched aplastic anemia patients and adults without aplastic anemia examined lumber MRI with PD-FFQ, and %CV and SD for vertebral bone marrow fat fraction were assessed and tested for differentiating two groups. Results: When applied feasible threshold value, specificity of %CV was significantly higher than that of SD (p=0.03). Impact: Proton density fat fraction quantification (PD-FFQ) with 6-point Dixon technique has a potential for hematopoietic ability assessment and diagnosis of aplastic anemia in adults.
Optimizing b-value Selection in MRI Diffusion Parameters for Hepatocellular Carcinoma: A Comparative Study of IVIM, DKI, and CTRW Models
Authors: Zhang Fan , Chen Gen , Wang Zixiong , Huang Mnegqi , Yin Ting , Chen Wei , Hu Xuemei
Published: November 2024

Motivation: Streamlining the number of b-values in MRI scans for hepatocellular carcinoma can significantly enhance diagnostic efficiency. Goal(s): To identify the minimal b-value pairs that correspond with comprehensive diffusion model parameters, potentially simplifying future scanning protocols. Approach: Employed MRI diffusion parameters across 11 b-values in 35 patients, comparing IVIM, DKI, and CTRW metrics with sADC values derived from varied b-value combinations. Results: Discovered specific b-value pairs that closely matched the diffusion parameters of comprehensive models, suggesting a possible reduction in required b-values for accurate diagnosis. Impact: This study could substantially refine MRI protocols, improving tumor characterization and grading while ensuring data quality with fewer b-values.
The differential diagnostic value of APT combined with Gd-BOPTA in IMCC and SHHM.
Authors: Xu Yiran , Li Jun , Zhao Ying , Ren Xue , Liu Ailian , Lin Liangjie
Published: November 2024

Motivation: IMCC and SHHM have similarities in imaging manifestations, are prone to confusion, and the treatment methods are different, once misdiagnosed, it seriously affects the patient's treatment and prognosis. Goal(s): This study aims to explore the differential diagnostic value of amide proton transfer (APT) combined with Gd-BOPTA in IMCC and SHHM. Approach: Retrospective analysis, normality testing, logistic regression, ROC analysis, and other methods were used for the study. Results: APT, LLR, and LSIR have significance in the differential diagnosis of IMCC and SHHM. When combined with LLR and LSIR, APT improves the differential efficiency. Impact: This study helps to more accurately distinguish IMCC from SHHM, thus adopting the correct treatment method, which is of great help to the treatment and prognosis of patients.
High-fidelity Breath-hold Liver DWI Through Self-referenced and Collaborative PROPELLER-EPI Reconstruction Based on POCSMUSE (SCOPUSE)
Authors: Xiong Hailin , Liang Liyuan , Chen Shihui , Yuan Chenglang , Xu Xiaorui , Chang Hing-Chiu
Published: November 2024

Motivation: Diffusion-weighted PROPELLER-EPI (periodically rotated overlapping parallel lines with enhanced reconstruction using EPI as signal readout) can enable high-fidelity free-breathing liver DWI. Goal(s): It is challenging to acquire liver DW-PROPELLER-EPI with breath hold for improving the acquisition efficiency. Approach: In this study, we proposed a self-referenced and collaborative PROPELLER-EPI reconstruction based on POCSMUSE (SCOPUSE) framework that can 1) correct the Nyquist ghost phase errors, 2) minimize the streaking artifacts, and 3) enable breath hold for liver DWI. Results: This method can accelerate the acquisition of DW-PROPELLER-EPI data and provide improved image quality compared with conventional PROPELLER-EPI reconstruction pipeline. Impact: Breath-hold acquisition can reduce the respiratory artifact in liver DWI with high scan efficiency, however, the attainable image quality is often limited by the breath-hold time. The proposed SCOPUSE can enable breath-hold liver DW-PROPELLER-EPI acquisition for achieving high-fidelity liver DWI.
Value of sarcopenia as an imaging biomarker in patients with primary sclerosing cholangitis (PSC)
Authors: Ringe Kristina , Levers Alena , Pantke Judith , Lenzen Henrike , Düx Daniel , Klimes Filip , Taubert Richard , Wedemeyer Hans-Heinrich , Wacker Frank
Published: November 2024

Motivation: Sarcopenia has been associated with a higher risk of adverse outcomes in patients with chronic diseases. Goal(s): To evaluate sarcopenia as a prognostic biomarker in patients with primary sclerosing cholangitis (PSC). Approach: Muscle mass was measured in 231 PSC patients at the level of L3 and correlated with patient demographics, clinical scores and clinical endpoints. Results: Sarcopenia was more prevalent in women and in patients without concomitant inflammatory bowel disease. Muscle mass significantly correlated negatively with the MELD score, but not with solid clinical endpoints. Impact: While sarcopenia is highly prevalent in PSC patients, imaging-based quantification of muscle mass seems to be of limited prognostic value.
Advancing Free-Breathing Liver MRI at 7T with Pseudo-Spiral Cartesian Sampling and Phase-Shimming
Authors: Tavakkoli Mitra , Runderkamp Bobby , de Buck Matthijs , Noseworthy Michael , Nederveen Aart , Caan Matthan , van der Zwaag Wietske
Published: November 2024

Motivation: Ultra-high field (B0 ≥ 7T) MRI potentially offers high spatial resolution. However, 7T abdominal MRI is challenging due to B1+-inhomogeneities and patients’ breath-holding limits, especially for high-resolution scans. Goal(s): To develop a high-quality, free-breathing liver scan at 7T. Approach: We implemented a 3D-GRE with golden-angle pseudo-spiral sampling pattern at 7T, that allowed respiratory binning in a free-breathing acquisition followed by Compressed Sensing reconstruction. Phase-shimming was used to achieve a homogeneous signal intensity over the liver. Results: We successfully achieved 1.35x1.35x1.35mm3-resolution liver images with high image quality, including signal homogeneity over the entire liver, demonstrating the potential of free-breathing 7T liver MRI. Impact: This study addresses breath-holding and B1+-inhomogeneity challenges associated with 7T abdominal MRI. It could further the development of non-invasive and detailed liver visualization. Ultimately, this would alter clinical pathways and offer patients a more comfortable imaging experience.
Deep Learning Accelerated HASTE Sequence with denoising effect for the Evaluation of Pancreatic Cystic Lesions
Authors: Kim Jeong Woo , Lee Chang Hee
Published: November 2024

Motivation: Single-shot technique such as HASTE with one breath-hold and thin section images reconstructed by DL may allow detection and detailed characterization of pancreas cystic lesions. Goal(s): This study was aimed to assess the feasibility of single breath-hold HASTE using DLR with additional denoising effect for the evaluation of pancreas cystic lesions. Approach: Four HASTE sequences with/without DLR were obtained. Two radiologists independently reviewed four image sets for qualitative and quantitative analyses of image quality. Results: HASTE using DL with additional denoising showed higher image quality than conventional HASTE in both qualitative and quantitative analyses. It also showed lower variability in cyst size measurement. Impact: DL-accelerated HASTE sequence with denoising effect may be useful for reducing acquisition time with one-breath hold without compromising image quality in the evaluation of pancreatic cystic lesions. It may be applied to abbreviated MRI for follow-up of pancreatic cystic lesions.
Hepatobiliary phase images synthesis from multi-phase dynamic contrast-enhanced liver MR images using generative adversarial network
Authors: Liu Baoer , Li Shangxuan , Chen Guanjun , Deng Kan , Zhou Wu , Xu Yikai
Published: November 2024

Motivation: Hepatobiliary Phase (HBP) of Gd-EOB-DTPA-enhanced MRI is helpful for the detection and diagnosis of liver lesions but requires waiting 20 minutes after injection of contrast agent to obtain it. Goal(s): Therefore, we aimed to use deep learning to synthesize HBP to obtain HBP images more conveniently and efficiently. Approach: We used generative adversarial network to synthesize HBP from multi-phase dynamic contrast-enhanced images. Results: The results showed that the synthetic HBP images closely mimicked the real HBP images in quantitative and qualitative image analysis, which illustrated that the model could be used to synthesize HBP in clinic to shorten the acquisition time. Impact: This study proposed a more conveniently and efficiently method to obtain hepatobiliary phase images based on generative adversarial network, which can reduce the clinical burden.
Cerebral hemodynamics in the ageing marmoset monkeys using ECG-synchronized PCMRI.
Authors: Fonta Caroline , Arribarat Germain , Mescam Murial , Balédent Olivier , Desmoulin Franck
Published: November 2024

Motivation: Some cerebrovascular function alterations and cognitive changes are related to ageing. We investigated this issue in marmoset monkeys, offering human-like physiological models. Goal(s): We aimed at describing age-related changes in brain hemodynamics and their potential interest as early markers of normal/pathological ageing. Approach: We analyzed blood flow in intracranial arteries and sinuses by using ECG-synchronized PCMRI. Results: The arterial (basilar trunk and carotids) inflow and venous (inferior and superior sinuses ) outflow sequence is earlier and shorter along the cardiac cycle in old versus young adult marmoset brains. Consequently, neurofluid oscillations appear different during the cardiac cycle as a function of age. Impact: Our study highlights the importance of nonhuman primate models in studying age-related cerebrovascular changes, offering insights into the link between vascular health, brain ageing, and cognitive decline, with implications for early neurodegenerative diseases.
In Vivo Assessment of Cerebral β-Hydroxybutyrate Metabolism in APPNL-F/NL-F Mouse Model of Alzheimer's Disease using 2H MR Spectroscopy
Authors: Soni Narayan Datt , Swain Anshuman , Jacobs Paul , Juul Halvor , Reddy Ravinder
Published: November 2024

Motivation: Among all, glucose hypometabolism is a characteristic pathology in Alzheimer’s disease (AD), under such conditions β-Hydroxy butyrate (BHB) can serve as an alternate source of energy. Measurement of BHB metabolism using a sensitive method could serve as a method for early diagnosis of AD. Goal(s): To monitor BHB metabolism in APPNL-F/NL-F mice. Approach: Monitoring cerebral 2H2-Glx labeling in mice following subcutaneous administration of 2H4-BHB using pulse-acquired 2H-MRS. Results: Although rate of cerebral 2H4-BHB uptake was similar in wild type (WT) and AD mice, moderately enhanced labeling of 2H2-Glx was observed in AD mice compared to WT indicates relatively efficient BHB metabolism in AD. Impact: Although BHB metabolism has been monitored in human and rodent brains using PET and 13C-MRS, inherent limitations restrict their clinical translation. Using a safe and sensitive method like 2H-MRS could be helpful in studying BHB metabolism in various neurodegenerative diseases.
Correlations between alterations in resting-state functional dynamics and memory impairments in the TgF344-AD rat model of Alzheimer’s Disease
Authors: de Waegenaere Sam , Al-Awlaqi Alya , Berckmans Lori , Verhoye Marleen , Adhikari Mohit
Published: November 2024

Motivation: Resting-state fMRI studies of Alzheimer’s disease impact on brain’s function commonly use functional connectivity (FC) ignoring sensitive and dynamic readouts such as the co-activation patterns (CAPs) occurring at short timescales. Goal(s): We aimed to assess changes in CAPs, in addition to network-level FC, in a transgenic rat model of Alzheimer’s disease longitudinally. Approach: We acquired high temporal resolution resting-state fMRI and performed FC and CAP analysis. Results: We found increased lateral cortical network FC that correlated with memory impairments at the plaque stage, and hyper and hypoactivation of the default-mode-like-network and hippocampal regions in two CAPs at the pre-plaque and plaque stages respectively. Impact: Our findings demonstrate that metrics of brain dysfunction of Alzheimer’s disease derived from high temporal resolution resting-state fMRI not only explain behavioural manifestations but also capture alterations preceding plaque formation further validating their translational potential as an early, functional biomarker.
CSF Mimicking Phantom based Evaluation of CSF Flow using Phase Contrast and Diffusion Imaging on a Highly Efficient Head Only Gradient System
Authors: Jolicoeur Brock , Rice James , Rivera-Rivera Leonardo , Roldán-Alzate Alejandro , Johnson Kevin
Published: November 2024

Motivation: Accurate characterization of CSF flow dynamics is necessary for understanding of brain metabolite clearance pathways. Goal(s): To compare PC and DWI techniques for slow CSF flow velocity at 3T in a clinical scanner and a heald-only high performance gradient system using high fidelity ventricle phantoms. Approach: Flow pump experiments were performed on silicone phantom at each of the scanners using varying Vencs. Results: Greater velocity-to-noise ratio (VNR) gains and diffusion sensitivity were observed from scans collected on the high performance gradient systemImpact: Generating physiologically realistic cerebral ventricles phantom and leveraging high performance gradient systems can enable low CSF flow assessment for studying brain waste clearance pathways.
Longitudinal brain MRI and tauPET provide novel insights for Alzheimer’s Disease trial planning
Authors: Tomaszewski Michal , Wang Yuchuan , Christian Bradley , Johnson Sterling , Rowe Christopher , Herring W , Hostetler Eric
Published: November 2024

Motivation: Anatomical MRI plays an important role in Alzheimer’s Disease drug trials, yet the information it provides may not be fully utilized. Goal(s): Regional brain volume and its atrophy in conjunction with amyloid- and tau-PET can provide valuable information about disease progression and treatment response. Approach: Local brain atrophy was quantified and correlated with PET biomarkers. Results: Significant correlation was reported between atrophy and baseline tau-PET in the medial-temporal region as well as robust associations with disease stage and amyloid burden. These findings can be used to understand disease development and therefore capture modulation in pathology with anti-tau and other therapies in trials. Impact: Understanding the relationships between brain volumetrics, disease severity and tau burden, including significant correlation between medial-temporal atrophy and tauPET presented in this study allows for efficient measurement of treatment response in AD trials.
Association of Brain Diffusion-Tensor Parameters with Risk of Alzheimer’s Disease-Related Cognitive Decline
Authors: Guo Yihao , Liu Tao , Huang Weiyuan , Chen Huijuan , Zhou Xiaoyue , Chen Feng
Published: November 2024

Motivation: Diffusion-tensor parameters of projection and association neural fibers associated with glymphatic function may be able to predict the development of Alzheimer’s Disease (AD). Goal(s): To study the association between diffusion-tensor parameters and cognition in patients with AD, and investigate whether diffusion-tensor parameters relate to cognitive decline. Approach: Linear regression models were performed to examine associations between diffusion-tensor parameters and cognition. linear mixed-effects models were used to evaluate the association between the baseline ALPS index and cognitive decline. Results: There was a positive association between ALPS index and cognition. Higher ALPS index levels were associated with less cognitive decline over time. Impact: Higher ALPS index levels are associated with lower risk of AD-related changes. These findings suggest that ALPS index derived from diffusion-tensor parameters may provide useful AD progression or treatment biomarkers.
A Low-cost, Small-footprint Gradient Amplifier for Low Field MRI Based on GaN FETs
Authors: Bolding N Reid , Gosula Varun , Dupuis Andrew , Sun Jessie , Griswold Mark
Published: November 2024

Motivation: The gradient system can be the most expensive part of a low field MRI system with minimal construction costs. Current solutions have linear amplifiers which may not reach power requirements, requiring pricey off-the-shelf amplifiers. Goal(s): Reduce the cost of the gradient drivers by taking amplifier efficiency into consideration to enable better low field MRI system creations. Approach: Uses an amplifier topology more commonly used at higher power, an H-bridge, but a high switching frequency reduces filtering requirements. A modular design eases construction. Results: The amplifier we created attains an increased efficiency, a smaller size, and a lower cost to attain useful power. Impact: Gradient drivers can dominate the overall cost of low-field MRI scanners. Our amplifier costs under 80USD and is capable of a 120V 15A DC output with a bandwidth of 150kHz. It contributes to cost reduction of gradient drivers significantly.
Open-Source, High-Efficiency, Easily-Reconfigurable Switch-mode Current Driver for B0 Shimming and Local Field Control
Authors: Govindarajan Ishaan , Straney Donald , Rivas-Davilla Juan , Setsompop Kawin , Chew Hong En , Witzel Thomas , Wald Lawrence , Chang Yulin , Stockmann Jason
Published: November 2024

Motivation: Multi-coil arrays have demonstrated utility for higher-order B0 shimming, spatial encoding, and local field control. However, existing amplifiers used to drive these coils typically trade off efficiency and imaging noise. Goal(s): Demonstrate a proof-of-concept amplifier with both high efficiency and low imaging noise, while being easily reconfigurable for different loads impedances. Approach: A switch-mode amplifier with highly-integrated power stages, 6th-order LC filtering, and fully-digital control was developed. Its thermal performance, dynamic performance, and impact on imaging noise was tested. Results: Our amplifier demonstrated heatsink-free 10ADC drive capability, <25μs step response rise-times with multiple loads, acceptable disturbance rejection, all while minimally impacting image quality. Impact: We have demonstrated an open-source, proof-of-concept amplifier achieving power efficiencies of switch-mode designs while maintaining imaging noise levels akin to linear designs. Such an amplifier unblocks novel spatial encoding techniques and local field control applications. Development is active and ongoing.
Movable Linear Gradients Optimized on Non-Planar B0 Slice Profiles Used for Improving Spatial Encoding in a Non-Linear Low-Field MRI
Authors: Samardzija Anja , Ha Yonghyun , Sun Chenhao , Sun Heng , Gross Ryan , Galiana Gigi , Constable R.
Published: November 2024

Motivation: Spatial resolution in an open low-field MRI that uses surface RF coils for B1-encoding can be improved by repositioning the RF coils within FOV for each TR. However, this approach is limited by space constraints in the left-right dimension. Linear gradients, especially movable ones optimized for a slab, effectively supplement encoding in that direction. Goal(s): To improve spatial resolution in the left-right direction of an open low-field MRI. Approach: A linear gradient optimized on B0 slice volume is moved in the anterior-posterior direction dependent on readout slice location. Results: Movable gradients improve spatial encoding. Impact: There is an unmet need for open low-field MRIs that can accommodate patients of all sizes and disabilities: this approach to generating high spatial resolution images without the use of volume-encompassing gradients makes open MRI viable.
A comparison study of different eddy current measurements at low field portable MRI
Authors: Chen Suen , Xie Yunhao , Qiu Yueqi , Chen Hao , Luo Hai , Zhang Zhiyong
Published: November 2024

Motivation: Eddy current results in resolution degradation and unwanted phase variations. However, there have been relatively few eddy-current related studies carried out in low field recently. Goal(s): Our goal was to introduce and compare image-phase based and FID-phase based eddy current measurement techniques in a 64mT MRI system and reduced eddy-current effects. Approach: We employed a large phantom or six field probes to measure eddy-current-induced gradients shift. And we modeled them as sums of exponentially decaying components to compensate the gradient unit. Results: Eddy-current-induced field shift was initially about 350ppm, and reduced to 240ppm and 20ppm by these two methods. Impact: This work develops two methods for measuring eddy current in low-field MRI, especially for portable scanner, which help reducing eddy-current-induced effects and improving the image quality of clinical sequence (e.g. DWI, DTI) in low field scanner.
Halbach Magnet Design for Low-Field MRI using Higher-Order Halbach Shimming and Layer-independent Segmentation.
Authors: Anjulo Natnael , Bolding Reid , Sun Jessie , Srinivas Sai Abitha , Martens Michael , Griswold Mark
Published: November 2024

Motivation: Existing low-field magnet designs are too heavy. They often have small usable imaging regions and inconvenient bore diameters. Goal(s): To design a compact, lightweight, and portable low-field magnet system with a large usable imaging region and a small length-to-bore aspect ratio. Approach: Our approach includes data-driven higher-order Halbach-based shim design. We also employed Mu-metal to enhance the shimming. We further improved the homogeneity by discretizing the multilayered Halbach into segments. We used COMSOL multiphysics for simulation. Results: In COMSOL-based magnetostatic simulation, we achieved a compact, lightweight magnet design with an imaging region spanning over half the magnet's bore. Impact: The improvement of the low-field MRI design with a lightweight and inexpensive magnet system with a potential benefit in resource-constrained and point-of-care settings.
MRI4ALL Hackathon: Under a Week Build of Open-Source Gradient Coils for a Low-Field MRI
Authors: Samardzija Anja , Shang Yun , Mao Andrew , Lakshmanan Karthik , Sun Heng , Gruber Bernhard , Jordanova Kalina , Short Jeff , Ciancia Vito , Amrein Philipp , Littin Sebastian , Alon Leeor , Stockmann Jason
Published: November 2024

Motivation: High production costs limit the accessibility of MRI. To break this accessibility and cost barrier, we demonstrate that affordable gradients can be designed and built in less than two weeks using open-source software and conventional 3D printing. Goal(s): To develop X, Y, and Z gradients for an ultra low-field Halbach MRI. Approach: We used open-source software to design the gradients. The casing was 3D printed, and the coils were manually wound. The fields were measured using an open-source field-mapping probe. Results: We constructed gradients that generated magnetic fields with great correspondence to simulated fields. 2D images were acquired with a fast spin-echo sequence. Impact: Open-source software can be used to design, build, and test MRI gradient coils in a quick and affordable manner. This demonstrates that open-source software for design of MRI hardware can lead to more accessible MRI.
Detailed Investigations into Inward-Outward Ring for Portable MRI
Authors: Liang Tingou , Yu Wenwei , Li Erping , Li Bing Keong , Huang Shao Ying
Published: November 2024

Motivation: Halbach arrays that supplies transversal magnetic fields are widely used in portable magnetic resonance imaging (MRI), while the Inward-Outward ring (IO-ring) array that supplies longitudinal magnetic fields has great unrevealed potential yet remains under studied. Goal(s): We aim to inspect the potential of IO-ring to widen its range of applications in portable MRI. Approach: By identifying the key geometric parameters and examining their effects on field strength and pattern. Analyses were conducted and the potential applications were discussed. Results: IO-ring is shown to be a promising candidate for providing flexible magnetic field patterns for portable MRI in different application scenarios. Impact: The relationship between all design parameters of IO-ring and the corresponding field pattern, as well as some intuitive variants of IO-ring design has been explored, providing new insight to PMA design for portable MRI.
Design of pTx pulses with free RF and gradient waveforms for cardiac MRI at 7T: Initial results and comparison to kT-point pulses
Authors: Nagelstraßer Sophia , Egger Nico , Herrler Jürgen , Schirmer Judith , Uder Micheal , Nagel Armin
Published: November 2024

Motivation: Parallel transmission (pTx) pulses with fixed gradient trajectory such as kT-points have successfully demonstrated to benefit cardiac imaging at 7T. However, it is possible to optimize pTx pulses without restrictions regarding RF and gradient waveforms. Goal(s): Our aim was to optimize first pTx pulses with free RF and gradient trajectory for cardiac imaging. Approach: We designed tailored free pulses for 35 heart subjects and compared them in terms of flip angle (FA) homogeneity and applied energy dose to kT-point pulses. Results: Comparable performance in FA homogeneity was obtained for both pulse types, but the free pulses additionally achieved a reduction of SED. Impact: Generating homogeneous excitation while complying with RF power deposition regulations is a challenge for cardiac imaging at 7T. Designing pTx pulses with free RF and gradient waveforms allows for reduced SED and similar homogeneity compared to kT-point pulses.
Dynamic pTx pulse design with accelerated B1+-mapping for cardiac imaging at 7T
Authors: Egger Nico , Nagelstraßer Sophia , Schirmer Judith , Herrler Jürgen , Ruck Laurent , Wildenberg Saskia , Lanz Titus , Kimmlingen Ralph , Uder Michael , Schmitter Sebastian , Bitz Andreas , Nagel Armin
Published: November 2024

Motivation: Subject-specific pTx methods can counteract excitation inhomogeneities in UHF body imaging, but require lengthy calibration times. Calibrationless universal approaches exist but yield reduced homogeneity for similar SAR levels. Goal(s): Our aim was to evaluate the possibility of shortening the calibration time by accelerating the B1+-mapping process. Approach: For 35 heart subjects, tailored pTx pulses were designed on B1+-maps with different undersampling and their performance was compared to universal approaches regarding flip angle homogeneity and SAR. Results: Tailored pulses designed on accelerated, undersampled B1+-maps (TA=30s) result in improved homogeneity compared to universal pulses or in a roughly 2.5-fold reduction of SAR at comparable homogeneity. Impact: Subject-specific pTx pulses optimized on accelerated, undersampled B1+-maps allow for improved homogeneity or reduced SAR compared to universal pulses. Reduced SAR could benefit body imaging at 7T, since SAR limitations often prevent the optimal choice of acquisition parameters at UHF.
Design of dynamic kT-point pTx pulses for renal imaging at 7T
Authors: Schirmer Judith , Egger Nico , Herrler Jürgen , Nagelstrasser Sophia , Kopp Christoph , Uder Michael , Nagel Armin
Published: November 2024

Motivation: In ultra-high field MRI, transmit magnetic field (B1+) inhomogeneities are affecting kidney imaging. Goal(s): Our goal was evaluate dynamic kT-point pulses for homogenous excitation in bilateral renal imaging. Approach: Channel-wise B1+ maps of the kidneys were acquired for 15 subjects. Universal and individual kT-point pulses with different number of subpulses were calculated and evaluated. For one subject anatomical images were acquired with phase shims and dynamic kT-point pulses. Results: While fixed-phase shims still suffer from flip-angle inhomogeneity, universal and subject-specific dynamic pulses with non-selective 5kT-point trajectories improves flip-angle homogeneity in the kidney and enable imaging with homogeneous excitation. Impact: Our study evaluated universal and subject-specific kT-point pulses for kidney MRI at 7T. kT-point pulses substantially improve flip-angle homogeneity and universal pulses enable calibration-free imaging at ultra-high field, promising advances in high-resolution renal imaging.
Redesigning Parallel-transmit Pulses in Runtime to Correct for the Effect of Patient Motion on B1+-maps for Ultrahigh-field MRI.
Authors: Kopanoglu Emre , Blanter Katherine
Published: November 2024

Motivation: Low-field motion-tracking methods are insufficient at ultrahigh-field as motion also affects flip-angle . Goal(s): Our goal was to develop a method that can redesign pulses for ultrahigh-field MRI within 1 second. Approach: We implemented a method to rapidly recalculate the post-motion basis-functions needed for pulse design and complemented it with dictionary matching to reduce pulse computation times a of small-tip-angle multi-spoke multi-slice parallel-transmit pulse design method. Results: With basis-functions recalculated in 0.13 seconds/slice and pulses reoptimized in 0.18 seconds/slice, multi-slice multi-spoke parallel-transmit pulses can be redesigned in runtime using the proposed method. Redesigned pulses significantly reduce motion-induced error, yielding consistent excitation with pre-motion excitation. Impact: A pulse design method is developed that can redesign practical parallel-transmit pulses in under a second. It can correct for motion-related flip angle distortions at ultrahigh-field and will help facilitate scanning of patients who cannot remain still (e.g., paediatric, dementia).
Calibration-free Multidimensional Universal Refocusing Pulse Design for 3D Reduced Field-of-View Prostate Imaging
Authors: Yang Jiayao , Fajardo Jesus , Fessler Jeffrey , Gulani Vikas , Nielsen Jon-Fredrik , Jiang Yun
Published: November 2024

Motivation: Universal pulses have been shown to be robust to B1+ inhomogeneity for brain imaging at 7T, without time-consuming online design. A similar approach may be useful for designing multidimensional RF pulses for the 3D prostate imaging at 3T. Goal(s): To design a universal multidimensional refocusing pulse and demonstrate its potential use for reduced field-of-view imaging in the prostate. Approach: A three-dimensional universal refocusing pulse was designed using 6 subjects and validated in 12 subjects and in vivo prostate imaging at 3T. Results: The proposed 3D universal refocusing pulse achieved similar performance on seen and unseen subjects. We successfully acquired reduced field-of-view prostate images. Impact: Our simulation and in vivo results demonstrated the potential to design one universal 3D refocusing pulses for most subjects in prostate imaging.
Quantitative T1rho with pulsed spinlock Using Toggling Inversion Preparation
Authors: YU Ziqiang , Jiang Baiyan , Chan Queenie , Chen Weitian
Published: November 2024

Motivation: Conventional T1rho techniques require sufficiently long TSL (time of spinlock) to ensure reliable T1rho quantification, However, maximum TSL allowed in clinical MR scanners is often limited by SAR (specific absorption rate) and RF amplifier to ensure patient safety and prevent damage to the scanners. Goal(s): Our proposed toggling inversion preparation pulsed spinlock mitigates the problem by employing a train of spinlock pulses with a gap duration between two pulses. Approach: We Confirmed our conjectures using simulation, phantom, and in vivo experiment. Results: Our approach can achieve reliable T1rho quantification using longer TSL compared to the conventional spinlock technique. Impact: The Proposed method has potential to enable T1rho imaging of tissue with relatively long relaxation time and at MRI system where continus spin-lock is challenging.
Probe-based co-simulation method for irregular wireless RF coils
Authors: Lu Ming , Yang Yijin , Zhu Haoqin , Yan Xinqiang
Published: November 2024

Motivation: There is a lack of tools for predicting the component values for such irregular wireless volume coils. Goal(s): The goal is to propose a novel co-simulation method that accurately predicts the capacitance distribution of irregular volume coils. Approach: We validated this method using various shapes of irregular volume coils, including bottle-shaped, dome-shaped, and elliptical coils, at both 1.5 T and 3 T. Results: The consistency between the simulated and practical capacitance further confirms the accuracy and reliability of the proposed probe-based co-simulation methods. Impact: This co-simulation method can guide fabricating wireless irregular volume coils and can be extended to other types of wireless coils.
Application of Synthetic MRI in Neonatal Brain Myelin Development Evaluation
Authors: Liu Shili , Chen Zhiqiang , Zhang Shaoru , Zhou Yunshu , Zhang Ruodi , Chen Xiaohua , Xiong Yuhui , Wang Aijun
Published: November 2024

Motivation: Conventional MRI sequences used in clinical practice cannot quantitatively evaluate the development of white matter in newborns. Goal(s): To explore the feasibility and application value of Synthetic MRI (SyMRI) in cerebral white matter myelin development of full-term neonates. Approach: Use intra-group and inter-group comparison of quantitative relaxation metrics obtained by SyMRI to evaluate the white matter myelin development level in newborns of different gestational ages. Results: Quantitative relaxation metrics derived by SyMRI can quantitatively evaluate the formation of myelin and brain maturity in full-term newborns. T1 and T2 values in different regions can reflect the differences in myelin sheath formation time. Impact: SyMRI can be used in clinical practice to investigate the myelin development of white matter in full-term newborns, and provide imaging basis for early detection and diagnosis of neonatal brain developmental dysplasia and disease conditions in newborns.
Diffusion Tensor Imaging Along the Perivascular Space Index in Idiopathic Intracranial Hypertension
Authors: Finkelstein Alan , Schartz Derrek , Schifitto Giovanni , Zhong Jianhui
Published: November 2024

Motivation: Idiopathic intracranial hypertension (IIH) is caused by elevated intracranial pressure of unknown etiology. In recent years, growing evidence has suggested that impaired glymphatic clearance may mediate IIH pathogenesis. Goal(s): We hypothesized that individuals with IIH would exhibit impaired glymphatic outflow, which could be directly measured using diffusion tensor imaging along the perivascular space (DTI-ALPS). Approach: This work used DTI-ALPS to investigate glymphatic clearance in individuals with IIH, and its association with symptom severity and comorbidities. Results: Impaired glymphatic clearance was directly related to the clinical severity of IIH, as suggested by a lower DTI-ALPS index. Impact: We employed perivascular diffusion tensor imaging to study glymphatic flow in IIH patients. Lower ALPS index correlated with greater clinical severity, offering insights into IIH's pathomechanism and its potential for diagnosis and treatment evaluation.
Progressive brain volume alterations in the zQ175DN mouse model of Huntington’s Disease using in vivo MRI
Authors: Vidas-Guscic Nicholas , Vasilkovska Tamara , Pluym Stefanie , van Rijswijk Joëlle , Van Audekerke Johan , Tang Haiying , Cachope Roger , Pustina Dorian , Van der Linden Annemie , Bertoglio Daniele , Verhoye Marleen
Published: November 2024

Motivation: Robust translational imaging biomarkers are needed to facilitate the development of disease-modifying treatments for Huntington’s disease (HD), a rare inherited neurodegenerative disease. Goal(s): To determine the use of structural atrophy determined with MRI as a robust translational biomarker for testing therapeutics in mouse models prior to people with HD. Approach: In this work, we used semi-automatic delineations and tensor-based morphometry (TBM) of 3D high-resolution anatomical MR images to assess structural anomalies in the knock-in zQ175DN model of HD at different ages. Results: We detected progressive volumetric decrease in the zQ175DN mouse model, offering a powerful translational biomarker for the assessment of disease-modifying therapies. Impact: We report the first brain-wide structural study of zQ175DN mice using in vivo MRI. Our work supports structural atrophy as a robust translational biomarker for testing therapeutics in mouse models prior to people with HD.
The impact of high-fat, obesogenic diets on brain volume in a commercially available mouse model of fatty liver disease.
Authors: Tee Sui-Seng , Jiang Li , Elsaid Salaheldeen
Published: November 2024

Motivation: Large-scale brain imaging studies have shown a significant association between altered brain structure in obesity. However, the exact biological processes remain elusive. Here, we use inbred mice, fed diets with pre-determined caloric contributions to elucidate diet-specific contributions to brain structure alterations in obesity. Goal(s): The goal of this study is to perform morphometric analysis of the brains of a commercially available mouse model of obesity. Approach: Mice were fed regular (5% fat), or obesogenic diets (40% fat). After 8 weeks all mice were scanned using MRI. Results: Obese mice show volume reduction, but not statistically significant. Neocortical volumes were larger in obese mice. Impact: The use of commercially available, diet-induced, obese mouse models provides an opportunity for the neuroimaging community to produce consistent structural and functional to support the assertion that obesity may be a ‘brain disease’.
Assessment of arterial and venous sinuses cerebral blood flows in rats with phase contrast MRI
Authors: Fall Sidy , Abderrahim Kamel , Baledent Olivier
Published: November 2024

Motivation: Several human cerebral diseases are associated to neurofluids dynamics alterations and continue to require preclinical research studies. Rat models were widely used to understand these diseases but its cerebral hemodynamic is not fully elucidated. Phase contrast (PCMRI) allows noninvasive quantification of blood flow dynamics. Goal(s): Our goal was to investigate both cerebral arterial and venous sinuses flows in rats. Approach: Twelve Sprague-Dawley rats underwent a 7T preclinical MRI. PCMRI quantified blood flows dynamics in the internal/external carotid arteries, basilar artery and transverse sinuses during cardiac cycle. Results: We obtained physiological references of cerebral blood flows parameters for these main cerebral vessels in rats. Impact: This study highlights the potential of PCMRI to investigate cerebral blood flows dynamics in rats. These findings may be important to study neurofluids dynamics interactions, pressure and compliance, to better understand human idiopathic pathologies such as hydrocephalus and intracranial hypertension.