bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved visualization of whole-brain structures and pathology at ultra-high field 7T MRI with parallel transmission universal pulses
Authors: Duan Caohui , Bian Xiangbing , Cheng Kun , Wang Song , Liu Linchang , Lyu Jinhao , Qu Jianxun , Mauconduit Franck , Lou Xin
Published: August 2024

Ultra-high field 7T MRI provides a significant increase in signal-to-noise ratio and contrast for noninvasively visualizing the brain, but is challenging to use for whole-brain imaging. In this study, we investigated the clinical potential of parallel transmission universal pulses (UP) for improving visualization of whole-brain structures and pathology. Our results show that UP enables remarkable signal contrast improvement throughout the brain, which is promising to improve lesion detection (e.g., brain metastases) and structures visualization over the whole brain.
Comparing the imaging performance of a three-channel endorectal coil for magnetic resonance imaging at 5T and 3T
Authors: Mo Zhiguang , Zhang Xiaoping , Liang Huageng , Tie Changjun , Xiao Wen , Cao Qi , Liu Chenchen , Zhang Xiaoliang , Li Ye
Published: August 2024

We made a three-channel endorectal coil for prostate imaging on the 5T magnetic resonance system and compared the imaging performance of the coils with the same structure on the 5T system and the 3T system. Prostate images at resolution of 0.78 mm × 0.78 mm × 2.5 mm were performed. In vivo prostate study shows that the endorectal coil works on the 5T system shows better image quality compared with the endorectal coil and surface coil array on the 3T system.
End-Grounded Dipole RF Element with Extended Coverage and Minimized SAR at 7T MRI
Authors: Chen Haiwei , Guo Lei , Gao Yang , Quan Zhiyan , Tang Xiaocui , Pan Sihong , Liu Feng , Zhang Xiaotong
Published: August 2024

Dipole RF coil suffers from high peak local SAR and limited imaging coverage. In this work, a novel dipole structure is proposed. Compared with the fractionated dipole, the proposed design achieves a substantially enlarged B1 field coverage and more than 25% SAR reduction by generating a uniform surface current on the coil. Experimental validations were conducted and agreed well with the simulation results.
Early Detection of Pancreatic Cancer by Hyperpolarized Magnetic Resonance and pO2 Electron Paramagnetic Resonance Imaging
Authors: Enriquez Jose , Howell Rian , Le Roux Olivereen , Pudakalakatti Shivanand , Dutta Prasanta , McAllister Florencia , Bhattacharya Pratip
Published: August 2024

There is an unmet need for the early diagnosis of pancreatic cancer. Diagnosis is difficult due to the asymptomatic nature of pancreatic cancer. One way to detect the early stages is to monitor the altered metabolism in premalignant pancreatic lesions in vivo with hyperpolarized metabolic imaging. Here we demonstrate how genetically engineered mouse models were used to detect early stages of pancreatic cancer as we see an increase in the altered metabolism in the pancreatic cancer models compared to control mice. Simultaneously we observe changes in hypoxia levels in these models using electron paramagnetic resonance imaging.
VI-RADS combined with decision tree model preoperatively predict the pathological grade of bladder cancer with high (≥3) and low (≤2) scores
Authors: Cao Bohong , Li Qing , Jiang Shuai , Zhang Yunfei , Dai Yongming , Zhou Jianjun
Published: August 2024

Bladder cancer pathology grading is currently obtained mainly by invasive cystoscopic biopsy or surgical pathology. This study aimed to investigate the effectiveness of Vesical Imaging Reporting and Data System (VI-RADS) in the diagnosis of high-grade bladder cancer (HG-BC) and explore a new preoperative non-invasive grading prediction system. We demonstrate that most bladder cancers with a VI-RADS score ≥3 are high-grade and that the decision tree model is a good predictor of pathological grading in patients with VI-RADS ≤2. Thus, VI-RADS can be a grouping imaging biomarker for noninvasive prediction of bladder cancer grade.
Second-order motion compensated single-shot spin echo planar imaging sequence using Compressed SENSE: a pilot study
Authors: Chen Rui , Luo Wei , Wu Zhigang , Xu Yongzhou , Liu Hui , Liu Zaiyi
Published: August 2024

Cardiac diffusion weighted imaging (DWI) is a novel tool that could provide non-invasive in-vivo microstructural assessment. However, cardiac DWI remains a challenging task due to low signal-to-noise-ratio (SNR) and motion artifacts. The second-order motion compensated (M2C) could be used to decrease the motion artifacts, and Compressed SENSE could improve the SNR of the echo planar imaging (EPI) based sequences. Hence, the combination of M2C DWI and Compressed SENSE was firstly proposed in the present study. We found that M2C DWI using Compressed SENSE showed better overall image quality and higher SNR.
Computed DWI with 2nd Order motion Compensated DWI for Diagnosis of the Myocardial Infarction without Contrast Agents
Authors: Luo Wei , Chen Rui , Wu Zhigang , Liu Hui , Liu Zaiyi
Published: August 2024

Diagnosis of myocardial infarction (MI) remains challenge since it’s still difficult to quantify the infarction area, and to assess prognosis. Cardiac DWI could provide essential information for diagnosis of MI without exogenous contrast agents. Higher b-value DWI could improve the detection rate of myocardial infarction, but it is challenging for image acquisition in cardiac DWI due to low SNR and motion. The present study aimed to combine the 2nd order motion compensated diffusion with computed DWI to overcome these challenges. Results of this study indicates the combination is potentially a promising and valuable non-invasive method in detection of MI.
Application of cardiac diffusion imaging with second-order motion compensation and breath hold in the diagnosis of acute myocardial infarction
Authors: Ruan Xiaowei , yang yanbing , wang yishi , yue Xiuzheng
Published: August 2024

Cardiac magnetic resonance imaging can non-invasively evaluate the anatomy and function of the heart, and has been widely used in various fields of cardiovascular diseases. This study explores the diagnostic value of DWI in the evaluation of acute myocardial infarction. The preliminary results of 17 patients showed that the ADC value of infarcted myocardium was significantly reduced, and DWI had the ability to diagnose acute myocardial infarction.
Multi-echo NODDI for the study of tissue compartmentalisation in transient ischaemic stroke: initial insights
Authors: Farrher Ezequiel , Chiang Chia-Wen , Choi Chang-Hoon , Cho Kuan-Hung , Huang Sheng-Min , Chen Ming-Jye , Kuo Li-Wei , Shah N. Jon
Published: August 2024

Neurite orientation dispersion and density imaging (NODDI) has been broadly used in diffusion MRI for the characterisation of tissue microstructure in healthy ageing and the diseased brain. However, the compartment-specific volume fractions provided by NODDI suffer from echo-time (TE) dependence due to differences in the compartment-specific transverse relaxation times. The recently proposed multi-TE NODDI (MTE-NODDI) model provides both TE-independent compartmental volume fractions and compartment-specific transverse relaxation times. Here we aim to assess the benefits and limitations of using MTE-NODDI for studying the brain tissue microstructure affected by transient ischaemic stroke in MCAo animal models.
Free-water DTI and cognitive performance in patients with intracranial vascular occlusion disease and transient ischemic attack
Authors: Fang Siyuan , Hai Jian , Li Gaiying , Wu Yupeng , Zhao Weiwei , Li Jianqi
Published: August 2024

The objective of this study was to explore the relationship between cognitive impairment and free-water elimination DTI (FWE-DTI) metrics in patients with intracranial vascular occlusion disease (IVOD) and transient ischemic attack (TIA). 22 IVOD with TIA patients were tested with cognitive scales and scanned using a 3T echo-planar imaging sequence. The results show global FWE-DTI metrics were associated with patients' cognitive performance in some domains, which indicated the potential of FWE-DTI as new indices for assessing global brain changes in this disease.
A general quantitative diffusion MRI model of water exchange, confinement, and hindrance with arbitrary gradient waveform encoding
Authors: Li Sisi , Shi Diwei , Jiang Xiaoyu , Chen Li , Zheng Quanshui , Guo Hua , Xu Junzhong
Published: August 2024

This study proposed and validated a general diffusion MRI biophysical model enabling simultaneous estimation of cell size, intracellular volume fraction, and transcytolemmal water exchange. The model introduces two-mode intracellular diffusion, corrects for restriction-induced “edge-enhancement” effect, and handles arbitrary diffusion gradient waveforms. The results of both in silico and in vitro experiments suggest this model not only improves the accuracy of estimated microstructural parameters such as cell size but also provides reasonable estimates of water exchange rate constant that is usually ignored previously. Such a comprehensive model may have potential to probe tumor status more precisely which is feasible in clinics.
Mapping biophysical changes in stroked tissue via the Standard Model with Exchange (SMEX) diffusion model
Authors: Alves Rita , Henriques Rafael , Olesen Jonas , Jespersen Sune , Shemesh Noam
Published: August 2024

Apparent diffusion coefficient (ADC) contrasts in stroke are still debated over 30 years after their discovery, mainly because of the nonspecific nature of ADC. Here, we harness Standard Model with Exchange (SMEX) measurements in ex-vivo stroked brains, to investigate how tissue microstructure is changed with ischemia. SMEX provides insight into neurite density, diffusivity and – importantly – exchange between neurite and extracellular environments. Using an extensive dataset, we find changes in neurite density and diffusivity that are consistent with neurite beading effects, which were further confirmed histologically. Dramatic reductions in exchange rates in the ischemic core were also observed.
Co-Hyperpolarized [13C,15N2]urea + [1-13C]pyruvate for Perfusion and Metabolic Imaging of the Abdomen in Healthy Volunteers
Authors: Kim Yaewon , Chen Hsin-Yu , Nickles Tanner , Gordon Jeremy , Larson Peder , Liu Xiaoxi , Magat Louise , Lee Philip , Gebrezgiabhier Daniel , von Morze Cornelius , Vigneron Dan , Ohliger Michael
Published: August 2024

[13C,15N2]urea and [1-13C]pyruvate were polarized together using dynamic nuclear polarization and simultaneously injected into healthy volunteers for simultaneous imaging of metabolism and perfusion in the abdomen. Whole-abdomen images were successfully obtained and the distribution of urea was compared to pyruvate and its metabolites. While the relative intensity in various organs were similar between urea and pyruvate, the temporal courses were different. This represents the first use of co-polarized pyruvate and urea in the human abdomen, and will be a powerful potential tool for simultaneous imaging of perfusion and metabolism in tumors and metabolic diseases.
Estimating T2 relaxation rates of Lactate with Hyperpolarized C13 MRI using bSSFP and Pharmacokinetic Modelling
Authors: Sahin Sule , Liu Xiaoxi , Dwork Nicholas , Tang Shuyu , Wang Zhen , Larson Peder
Published: August 2024

Lactate T2 values were fit in vivo for animal and human hyperpolarized carbon-13 pyruvate MR datasets. A pharmacokinetic model was used to leverage T2 weighting of a bSSFP acquisition. For healthy rat kidneys lactate T2 values were 0.929 ± 0.111s, for TRAMP tumor 1.663 ± 0.485s, for human RCC tumor 1.119 ± 0.168s and for human RCC normal-appearing region 1.089 ± 0.375s. Lactate T2 maps showed heterogeneity across the kidney of RCC patients but median T2 values were consistent across patients. This work demonstrates a method of using bSSFP hyperpolarized data to fit T2 values.
Data Standardization and DICOM Integration for Hyperpolarized 13C MRI
Authors: Diaz Ernesto , Sriram Renuka , Gordon Jeremey , Sinha Avantika , Liu Xiaoxi , Bernard Jenna , Vigneron Daniel , Wang Zhen , Xu Duan , Larson Peder
Published: August 2024

Hyperpolarized (HP) 13C MRI has shown promise as a valuable modality for in vivo measurements of metabolism, and is currently in human trials at over 15 human research sites worldwide. It is important to adopt standardized data storage practices as it will allow sites to meaningfully compare data. We propose using specific Attributes in DICOM format, including “Contrast Agents”, and provide a Python based implementation to add these values for individual studies. Moreover, we propose best practices for HP 13C MRI data storage that will support future multi-site trials and research studies and technical developments of this imaging technique.
Metabolic Dysregulation in Rat Brain with Diabetes and Alzheimer’s Disease as Assessed by Hyperpolarized [1-13C] Pyruvate
Authors: Datta Keshav , Liu Shie-Chau , Rehman Usman , Graham James , Hurd Ralph , Spielman Daniel , Jue Thomas
Published: August 2024

Epidemiology studies have detected type 2 diabetes (T2D) increasing the risk of Alzheimer’s disease (AD). How insulin insensitivity in T2D influences AD onset/progression poses a puzzling question. In this study using dynamic nuclear polarization (DNP) magnetic resonance (MR) experiments, we interrogated the metabolic alteration by following the conversion of [1-13C]Pyr in the brain of control (CRL), T2D with no AD (T2D-AD -/-), and T2D with AD (T2D-AD +/-) rats. Pyruvate dehydrogenase (PDH) activity decreases in T2D and decreases further in T2D with AD.
Increasing the hyperpolarization level on PHIP-SAH polarized pyruvate in a fully biocompatible solution.
Authors: Reineri Francesca , Aime Silvio , Carrera Carla , Cavallari Eleonora , Cerutti Erika , Di Matteo Ginevra
Published: August 2024

Hyperpolarized [1-13C]pyruvate can be obtained by means of ParaHydrogen Induced Polarization-Side Arm Hydrogenation, a hyperpolarization technique that is significantly more cost effective and faster than the gold-standard method d-DNP. The hyperpolarization level that we reported previously, for the fully biocompatible aqueous solution of this HP metabolite, was sufficient to carry out metabolic studies, but still low. In this work we show that the use of a lower catalyst concentration, together with a co-catalyst, and an improved magnetic field cycle profile for spin order transfer can double the HP level on this metabolite.
Towards Biomedical Applications of Parahydrogen Induced Polarization by Side-Arm Hydrogenation Using SAMBADENA
Authors: de Maissin Henri , Mohiuddin Obaid , Herzog Marvin , Chekmenev Eduard Y. , Korchak Sergey , Glöggler Stefan , Hövener Jan-Bernd , Zaitsev Maxim , Elverfeldt Dominik v. , Schmidt Andreas B.
Published: August 2024

Parahydrogen-induced Polarization (PHIP) by Synthesis Amid the Magnet Bore Allows Dramatically Enhanced Nuclear Alignment (SAMBADENA) of agents in situ within the MRI magnet and requires very little hardware in addition to the MRI system. However, side-arm hydrogenation (PHIP-SAH), fast side-arm cleavage and purification have not been attempted yet. Here, we present a SAMBADENA setup made from commercially-available components for future preclinical applications. Using this setup, we demonstrate high 13C polarizations of 17% for 25mM ethyl-[1-13C]-acetate. In addition, for ethyl-pyruvate, fast side-arm cleavage and removal of 96% of the organic solvent within 10s to obtain pyruvate in neat water is demonstrated.
A Deep Learning-based Multi-Contrast MRI Registration Model with a Realistic Flow Field and Reduced Over-Smoothing Effect
Authors: Li Yiheng , Chamberlain Ryan
Published: August 2024

To optimize DL-based medical registration models to produce a more realistic flow field and reduce the over-smoothing effect of deformable registration while keeping the generalizability of the multi-contrast registration model to work on all anatomical structures and contrast of MRI, we proposed an algorithm that adopts the image synthetic framework from SynthMorph and optimized with cycle-consistent loss. By experimenting with the jacobian loss, bidirectional loss, and cycle-consistent loss, we managed to further optimize the results of registered images. The evaluation of two MRI image datasets, the BraTS dataset, and the LSpine dataset, demonstrated the increased SSIM, PSNR, and LocalNCC.
Novel Uunsupervised Segmentation of Bone Marrow Edema-Like Lesions using Bayesian Conditional Generative Adversarial Networks
Authors: Yu Andrew , Gaj Sibaji , Holden William , Lartey Richard , Kim Jeehun , Winalski Carl , Subhas Naveen , Li Xiaojuan
Published: August 2024

Quantitative assessment of the bone marrow edema-like lesions and their association with osteoarthritis requires a consistent and unbiased segmentation method, which is difficult to obtain in the presence of human annotators. This study proposes an unsupervised approach using Bayesian deep learning and conditional generative adversarial networks that detects and segments anomalies without human intervention. The full pipeline has a lesion-wide sensitivity of 0.86 on unseen scans. This approach is expected to be generalizable to other lesions and/or modalities.
Cerebrovascular segmentation of mouse TOF-MRA using 3D U-Net
Authors: Wu Yue , Zhang Jinyuan , Li Zhixin , Yang Yishuang , Zhuo Yan , Zhao Xudong , Zhang Zihao
Published: August 2024

Time-of-flight MR angiography (TOF-MRA) allows noninvasive visualization of the mouse intracranial vessels. However, there is no available tool for vessel segmentation in mouse 3D TOF-MRA. In this study, we developed an automated vessel segmentation method based on a convolutional neural network and multiscale vessel enhancement filtering algorithm. The method is potentially useful in the preclinical studies of cerebrovascular diseases.
Automated deep learning based segmentation of abdominal adipose tissue on whole-body MRI in a population-based study of adolescents
Authors: Wu Tong , Estrada Santiago , Gils Renza , Su Ruisheng , Jaddoe Vincent , Oei Edwin , Klein Stefan
Published: August 2024

This study is embedded in the Generation R Study, a population-based prospective cohort study in the Netherlands. Whole-body Dixon MRI scans were performed at age 13 years. A previous neural network (CDFNet) has been published that was trained on adults. We aimed to retrain this network on our MRIs in the Generation R Study. The obtained segmentations are in strong agreement with expert-generated manual segmentations and can therefore greatly reduce the manual workload. Therefore, for accurate abdominal fat quantification, segmentation of both subcutaneous and visceral adipose tissue, on Dixon MRIs of adolescents is feasible with a retrained convolutional neural network.
A novel federated learning framework for accurate and secure multi-center MS lesion segmentation
Authors: Liu Dongnan , Cabezas Mariano , Wang Dongang , Tang Zihao , Zhan Geng , Kyle Kain , Ly Linda , Yu James , Shieh Chun-Chien , Sullivan Ryan , Calamante Fernando , Barnett Michael , Ouyang Wanli , Cai Weidong , Wang Chenyu
Published: August 2024

Multiple sclerosis (MS) is a neurodegenerative disease of the central nerve system (CNS), which has the potential to cause a neurological disability, particularly for young adults. Recently, deep learning-based techniques are important for MS diagnosis and treatment, since they can segment the lesions caused by MS automatically and accurately. However, their applicability to multi-center scenarios is limited, due to the privacy and security issues in data sharing. To tackle these limitations, a decentralized deep learning framework is designed in this work, which can bring accurate multi-center MS lesion segmentation performance without sharing the raw data.
Cycle Inverse Consistent Deformable Medical Image Registration with Transfomer
Authors: Zhang Chenghao , Morgan Mikhail , Yang Yanting , Tian Ye , Guo Jia
Published: August 2024

Deformable image registration is a crucial part of the medical image process that seeks to estimate an optimal spatial transformation to align two images. Traditional methods neglect the inverse-consistent property and topology preservation of the transformation, which can lead to errors in registration results. To address these issues, we propose the cycle inverse consistent transformer-based deformable medical image registration model. We adopt Swin-UNet to achieve higher registration performance and comprehensively consider the inverse consistency loss function to guarantee a more accurate registration. Our pipeline can be trained to create study-specific templates of images for diagnostic and/or educational purposes.
Deep learning Based Automatic Segmentation of Brain Magnetic Resonance angiography Images
Authors: An Liying , Meng Fanyang , Yu Kaixin , Zhang Lei , Zhang Huimao
Published: August 2024

Accurate cerebrovascular segmentation plays an important role in clinical diagnosis and the related research. Magnetic Resonance angiography (MRA) postprocessing manually recognized by technologists is extremely labor intensive and error prone. However, automatic segmentation of brain vessels remains challenging because of the variable vessel shape and high complex of vessel geometry. We propose an artificial intelligence brain vessel segmentation system supported by an optimized physiological anatomical-based 3D convolutional neural network that can automatically achieve brain MRA vessel segmentaion in healthcare services. The overall segmentation accuracy of the independent testing dataset is 0.931.
Deep learning-based groupwise registration for longitudinal MRI analysis in glioma
Authors: Hammecher Claudia Chinea , van Garderen Karin , Smits Marion , Wesseling Pieter , Westerman Bart , French Pim , Kouwenhoven Mathilde , Verhaak Roel , Vos Frans , Bron Esther , Li Bo
Published: August 2024

Glioma growth may be quantified with longitudinal image registration. However, the large mass-effects and tissue changes across images suposse an added challenge. Here, we propose a longitudinal, learning-based and groupwise registration method for the accurate and unbiased registration of glioma MRI. We evaluate on a dataset from the Glioma Longitudinal AnalySiS consortium and compare to classical registration methods. We achieve comparable Dice coeffients, with more detailed registrations, while significantly reducing the runtime to under a minute. The proposed methods may serve as an alternative to classical toolboxes, to provide further insight into glioma growth .
An application of parallel imaging and deep-learning reconstructed T2 mapping in nasal cartilage
Authors: Liu Weiyin , Gao Yufan , Zha Yunfei
Published: August 2024

Rhinoplasty is a reversible surgery; MRI became a non-invasive post-surgery tracking approach to assess the influence of implant-compressed on nasal cartilage such as mechanical stress, cellular organization and tissue degeneration, etc. Widely-used T2 mapping in musculoskeletal imaging such as knee, shoulder and pelvics takes long acquisition time and thus deters clinical utility. With greater number of multi-channel coils and parallel imaging techniques, scan time shortens but noise enhances. With the additional deep-learning reconstruction, T2 mapping with parallel imaging was stable with small RMS CV% = 0.077% to parallel imaging only image data sets.
Evaluating the relationship of proximal femoral bone shape asymmetry with cartilage health and biomechanics in patients with hip OA
Authors: Thahakoya Rafeek , Pedoia Valentina , Gao Kenneth , Bhattacharjee Rupsa , Gassert Felix , Luitjens Johanna , Roach Koren , Hammond Eric , Souza Richard , Majumdar Sharmila
Published: August 2024

This current study evaluated the role of bone shape asymmetry with other biomarkers of hip OA such as T1rho/T2 relaxation time and gait biomechanics data. We observed similar relationship trend in higher bone asymmetry values in the AMS region correlates with lesser number of repetitions performed 30s chair rise test, validating the common understanding of performance. This is one of the first feasibility studies to be explored which conveys the potential of bone asymmetry to be considered as a strong biomarker for understanding hip OA
Evaluation of the effect on quantitative ultrashort echo time (UTE) biomarkers with cartilage dehydration and rehydration
Authors: Wan Lidi , Searleman Adam , Ma Yajun , Wong Jonathan , Tang Guangyu , Du Jiang , Chang Eric
Published: August 2024

Ex vivo and cadaveric articular cartilage samples often undergo freeze and thaw cycles and sample preparation in air. These procedures will result in cartilage dehydration and degradation, which may affect the results of UTE-biomarkers. This study was aimed to evaluate the effect of cartilage dehydration and rehydration on UTE-biomarkers and to compare the rehydration capability of synovial fluid and normal saline. Cartilage dehydration resulted in significant changes in all evaluated UTE-biomarkers. Rehydrating with normal saline had non-significant effect on UTE-biomarkers while synovial fluid resulted in significant changes for MMF and T2*. Rehydrating with normal saline is better than synovial fluid.
Quantitative MRI T2mapping in the knee joint using deep learning-based reconstruction for Compressed sensing
Authors: fu jiahui , wong chinting , mu lin , dong dong , qiu ying , Zhu yi , Jiang Ke , zhang huimao
Published: August 2024

MRI T2 mapping has been recommended as a noninvasive biomarker of knee cartilage lesions. However, due to the long acquisition time, it hasn’t been widely used in the clinical setting. Recently, deep learning-based acceleration of compressed sensing (CS) has shown promising results without losing image quality. The purpose of this study was to explore the feasibility of quantitative knee T2-mapping accelerated by deep learning-based compressed sensing (CS-AI), and compare the image quality and diagnostic performance with conventional CS. The results demonstrates that quantitative knee T2 mapping with reconstruction by CS-AI was feasible, suggesting better diagnostic performance without extra time consuming.
Relaxometric mapping of normal tissue using magnetic resonance fingerprinting (MRF)
Authors: Qian Enlin , Konar Amaresha , Fernandes Tiago , Paudyal Ramesh , Shukla-Dave Amita , Schwartz Lawrence , Geethanath Sairam
Published: August 2024

We explored the feasibility of T1 and T2 mapping of normal tissue (masseter muscle) in the head and neck (HN) region using magnetic resonance fingerprinting (MRF) and evaluated its repeatability. Our study included fingerprinting data from four healthy volunteers and four repeats each, along with acquiring B0 maps. The T1 and T2 estimation of masseter muscle by MRF is similar to previous literature values. We report wCV<4.3% for T1 measurements and wCV<7% for T2 measurements for all subjects. No significant B0 variations were observed in the masseter muscle regions.
Simulation of the Electric Transfer Function of Partially Inserted Guidewires
Authors: Godinez Felipe , Ipek Özlem , Hand Jeffrey , Ben Haj Fatima , Hajnal Joseph , Malik Shaihan
Published: August 2024

Endovascular interventional devices can heat when used in an MRI system. The heating mechanism can be evaluated using the electric transfer function. In this work we evaluated the TF for a partially inserted guidewire as used in practice, at frequencies corresponding to 0.55T, 1.5T, and 3T. The study revealed that the transfer function varies dramatically with insertion depth for some frequencies and not others.
Advanced RF antenna arrangements to improve the efficacy of Thermal Magnetic Resonance of Glioblastoma Multiforme at 7.0T, 9.4Tand 10.5T
Authors: Saha Nandita , Kuehne Andre , Millward Jason , Niendorf Thoralf
Published: August 2024

This work proposes the concept of four RF applicators combining SGBT dipole and loop building block antenna array for diagnostic proton (1H) imaging and thermal intervention at 7.0T, 9.4T and 10.5T. We demonstrated the relationship between spatial arrangement of the antennas in RF applicator and the SAR profile which further related to temperature rise for targeted thermal intervention of deep-seated brain tumors. This approach of design, simulation, optimization of EM power deposition followed by calculation of the resulting temperature distribution can be adapted as a pre-routine to conduct optimization result for individual patient for further treatment planning.
High permittivity material for catheter tracking in interventional imaging
Authors: Zhao Yunkun , Zhang Xiaoliang
Published: August 2024

This study presents a technique of using high permittivity dielectric materials for catheter tracking in interventional endovascular imaging procedures. The design includes a high dielectric material cylinder at the tip of the catheter. Given the small size and limited space of the catheters, it is challenging to implement the current catheter tracking techniques. In the proposed approach, the high permittivity material mounted on tip of the catheter can amplify the local magnetic fields and makes the catheter tip visible. This method doesn’t need any feeding cables and is not sensitive to the frequency shift which makes it easy to implement.
Initial experiences assessing the impact of different materials for needle-based interventional devices using advanced DWI and MR thermometry
Authors: Holmes James , Buelo Collin , Geng Ruiqi , Tarasek Matthew , Yeo Desmond , Brace Christopher , Hernando Diego , Faacks Aaron , Xu Jia , Donato Francisco , Wells Shane
Published: August 2024

In this work we report initial results evaluating the imaging artifacts associated with different candidate materials for use in needle-based interventions. The impact of each material was assessed using MRT and DWI ADC as well as compared with local Bo field maps.
Manganese-Phenolic Networks Platform Amplifying STING Pathway Activation for MRI Imaging Guided Cancer Chemo- /Immune Therapy
Authors: Pang Xinrui , Wei Ruili , Wang Ye , Liang Fangrong , Yang Ruimeng
Published: August 2024

Low immune infiltrates severely hinder cancer immunotherapy. Hence, we developed a manganese-phenolic networks platform (TMPD) The TMPD was based on doxorubicin (DOX) loaded PEG-PLGA nanoparticles and further coated with manganese (Mn)-tannic acid (TA) networks. Mechanistically, DOX could kill cancer cells while Mn2+ could significantly increase the activity of STING pathway related protein to amplify the STING signal and has the function of MRI T1 imaging. The nanoplatform could promote the presentation of tumor antigens and activate a robust innate and adaptive immunity, providing reference for the application of molecular imaging in tumor diagnosis and treatment.
Comparing parallel transmit 2-spoke against circularly polarized pulses for 7T whole brain diffusion MRI
Authors: Zhang Minghao , Ding Belinda , Dragonu Iulius , Liebig Patrick , Heidemann Robin , Rodgers Christopher
Published: August 2024

Diffusion MRI (dMRI) is inherently limited by SNR. 7T scans increase intrinsic SNR but suffer from regions of signal dropout, especially in temporal lobes and cerebellum. We applied dynamic parallel transmit (pTx) to allow whole-brain 7T dMRI and scanned 7 volunteers comparing pTx 2-spoke and circularly polarized pulses. PTx 2-spoke scans increased whole-brain mean temporal SNR increased by 22%, produced cleaner fractional anisotropy maps, and reduced fiber estimation uncertainty by 4% (P=0.016) for first fibers and 2% (P<0.001) for second fibers. However, less restrictive SAR limits will be needed for clinical translation of our approach due to long scan time.
RF mode switching based Tx coil system for B1+ homogeneity mitigation at 7T: basic concept and preliminary study
Authors: Urayama Shin-ichi , Fukunaga Masaki , Cloos Martijn
Published: August 2024

To mitigate B1 inhomogeneity problems in ultra-high-field MRI, we proposed RF-mode switching technique which doesn’t need an expensive parallel transmit (pTx) system. As a preliminary study, we developed an RF-switching circuit (one of the main parts of the system) and validated its function through phantom experiments. The results showed that the switching function works well, although a certain degree of power-loss was observed both at bench (< -1dB) and on the images. We have re-designed a new switching circuit and will continue to the development to demonstrate this technique at a fraction of the cost of a pTx system.
Design of human brain shim coil with high-density wire pattern translated from Stream Function
Authors: Su Shengyue , Henning Anke
Published: August 2024

In this work, we propose a B0 shim coil design method based on high-density wire pattern discretized from stream function optimization. We demonstrate that the magnetic field generated by the designed shim coil can fully match the theoretical magnetic field generated by continuous stream functions. We compared the performance of different current-carry surfaces over shim ability for stream function optimization. We also evaluated the impact of current limitation for the discretized coil on B0 shim result and power dissipation.
Silent slice-wise shimming with a multi-coil setup at ultrahigh-field MRI
Authors: Aghaeifar Ali , Scheffler Klaus
Published: August 2024

Multi-Coil shimming is advantageous because of its ease of use for effective local and slice-wise shimming. Shim coils are constructed of current-carrying conductor wires and undergo Lorenz force while placed in the magnet. Currents alteration in slice-wise shimming changes the magnitude and direction of force and imposes mechanical vibrations and acoustic noise. Here we propose strategies to control the level of inter-slice shims current change. The proposed strategies showed that inter-slice shims current change can be appropriately reduced by applying a minor change into shimming routine and without degrading shimming performance significantly .
On the spatiotemporal phase modulation of odd and even EPI echoes at 300 mT/m diffusion MRI: A field monitoring analysis
Authors: Llorden Gabriel Ramos , Park Daniel , Lee Hong-Hsi , Scholz Alina , Keil Boris , Wald Lawrence L. , Witzel Thomas L. , Huang Susie Y.
Published: August 2024

Most of EPI ghosting algorithms assume that odd/even of phase modulations, either of first or higher spatial order, are stationary through the readout. Hence, a phase maps (or a linear function) for the subset of odd and even k-space lines is judged enough to model Nyquist ghosting and obtaining ghosting free images. Nevertheless, we demonstrate with field monitoring that for high-gradient strength diffusion MRI, persistent eddy currents from the diffusion module interfere non-linearly with the image encoding, leading to phase modulations that are time-varying during the readout. Implications for existing ghosting correction algorithms and potential alternatives are discussed.
Development and clinical utility analysis of a prostate zonal segmentation model on T2-weighted imaging: a multicenter study
Authors: Xu Lili , Zhang Gumuyang , Mao Li , Li Xiuli , Sun Hao , Jin Zhengyu
Published: August 2024

Zonal segmentation is important in the management of prostatic diseases. Many studies have demonstrated the feasibility of training CNN models for zonal segmentation. However, they lack validation in non-public datasets and consideration of the patients’ characteristics. In this study, we validated the model’s utility for prostate zonal segmentation on T2WI in different external testing datasets. The model yielded good performance regardless of the variations in the patients’ clinicopathological characteristics. The model showed higher performance than the junior radiologist in PZ segmentation. Prostate morphology and MR scanner parameters, especially CG volume and vendor, impact zonal segmentation performance.
ADC histogram features of rectal cancer before and after neoadjuvant radiation to predict heterochronic hematogenous metastasis
Authors: Zhang Xiaoxian , Xu Chunmiao , Shen Zhiwei , Jiang Ke , Chen Xuejun
Published: August 2024

Bloodstream metastasis to the liver, lung, and bone is the most prevalent mechanism of rectal cancer metastasis. However, there are currently no good indications for diagnosing heterochronic hematogenous metastases at the early stage. Therefore, this study aimed to explore whether ADC histograms might predict new heterochronic hematogenous metastases before and after neoadjuvant radiation for rectal cancer. Results showed that the first-order histogram feature ADC5% derived from post-treatment ADC maps might be utilized as an imaging biomarker and an independent predictor of new heterochronic hematogenous metastases after surgery following neoadjuvant chemotherapy for rectal cancer.
Hybrid segmentation of ventilation defect regions in low signal-to-noise ratio hyperpolarized 129Xe MRI
Authors: Wang Cheng , Xiao Sa , Li Zimeng , Li Haidong , Zhou Xin
Published: August 2024

Ventilation defect percentage (VDP) generated from hyperpolarized gas (3He or 129Xe) MRI is a sensitive indicator of lung disease. However, the commonly used K-means method for the calculation of VDP is not suitable for low signal-to-noise ratio (SNR) images. In this work, we proposed a hybrid segmentation method to segment the ventilation defect regions and calculate VDP values under low SNR conditions. The results show that the proposed method has improved both the accuracy of segmenting VDP map and calculating VDP value.
Batch-mode production of hyperpolarised xenon gas with a continuous-flow polariser for preclinical and clinical human lung ventilation images
Authors: Vaeggemose Michael , Norquay Graham , Hansen Esben , Stewart Neil , Rodgers Oliver , Munro Ryan , Schulte Rolf , Collier Guilhem , Laustsen Christoffer , Wild Jim
Published: August 2024

Hyperpolarised 129Xe gas was accumulated using spin-exchange optical pumping (SEOP) by continuous-flow of xenon gas directly from the cell without the use of cryogenic separation. 3D ventilation images were acquired in human and porcine models to determine clinical diagnostic image quality. Xenon ventilation image quality indicates that on demand batch production of xenon is feasible for both preclinical and clinical lung ventilation imaging examinations.
Chemical Shift Inversion Recovery (CSIR) spectroscopy with hyperpolarized xenon-129 MRI: A comparison with CSSR spectroscopy
Authors: Ruppert Kai , Loza Luis , Amzajerdian Faraz , Hamedani Hooman , Ismail Mostafa , Baron Ryan , Duncan Ian , Profka Harrilla , Kadlecek Stephen , Rizi Rahim
Published: August 2024

Chemical shift saturation recovery (CSSR) MR spectroscopy using hyperpolarized xenon-129 provides metrics of pulmonary physiology by saturating the xenon dissolved-phase magnetization in the lung with a 90° RF pulse and measuring the subsequent signal recovery via gas exchange. Our measurements in a rat demonstrate that chemical shift inversion recovery (CSIR) spectroscopy, which replaces the saturation with an inversion pulse, produces equivalent results to CSSR but with greater robustness with respect to both low signal amplitudes at short delay times and incomplete saturation.
Assessing Ventilation Dynamics of Lung Transplantation with Free-Breathing Hyperpolarized Xenon-129
Authors: Amzajerdian Faraz , Hamedani Hooman , Baron Ryan , Ismail Mostafa , Loza Luis , Ruppert Kai , Kadlecek Stephen , Rizi Rahim
Published: August 2024

Regional quantification of ventilation dynamics can provide valuable insights into the functional changes associated with both unilateral and bilateral lung transplantation, potentially improving diagnostic monitoring and providing a better understanding of underlying pathophysiology. By imaging hyperpolarized xenon-129 (HXe) continuously over an extended period of time, ventilation dynamics more representative of steady-state, physiological breathing were derived and used to assess differences between unilateral and bilateral transplant patients.
Semi-supervised segmentation for 3D medical image based on contrast learning
Authors: Huang Zhengyong , Zhang Na , Liang Dong , Liu Xin , Zheng Hairong , Hu Zhanli
Published: August 2024

Semi-supervised segmentation, using large amounts of unlabeled data and small amounts of labeled data, has achieved great success. This paper proposes a semi-supervised segmentation method based on consistent learning and contrast learning. It mainly uses a mean-teacher framework to add consistency losses and contrast losses based on multiscale features to minimize the distance of model responses under different disturbance inputs. In addition, mean square error loss was used to alternately minimize the gap between the teacher and student models. In 3D left atrium data, a Dice coeffivient of 0.8970 was obtained, which was superior to other methods.
3D T2 and T1ρ Mapping of Ischemic Injury to the Femoral Head: An In Vivo Piglet Model Study
Authors: Buko Erick , Albrecht Douglas , Armstrong Alexandra , Tóth Ferenc , Johnson Casey
Published: August 2024

Legg-Calvé-Perthes disease (LCPD) is a pediatric hip disorder caused by femoral head ischemia and osteonecrosis. In this work, we investigated whether 3D T2 and T1ρ relaxation time mapping are sensitive to ischemic injury to the bone and marrow of the femoral epiphysis and metaphysis following surgical induction of femoral head ischemia in a piglet model of LCPD. We found that T2 and T1ρ increased in the ischemic femoral epiphysis and decreased in the perfused metaphyseal spongiosa. Our findings support the potential clinical use of T2 and T1ρ mapping to assess the severity of femoral head injury in patients with LCPD.
AI inspired engineering of future MRI machines and components
Authors: Coupling J. , Current E. , Litting Line SP.
Published: August 2024

The topic of this contribution is how artificial intelligence (AI) can be used to engineer future magnetic resonance imaging (MRI) machines and components. MRI machines are vital tools in the medical field, used for everything from diagnosing injuries to detecting cancer. However, they are also extremely complex devices, made up of many different parts that must work together seamlessly.
RF Pulse Predistortion for Low-Field MRI Based on Spin Physics Using a Neural Network Amplifier-to-Bloch Equation Model
Authors: Albert Madison , Vaughn Christopher , Martin Jonathan , Srinivas Sai Abitha , Grissom William
Published: August 2024

In low-field MR, low-cost amplifiers with reduced fidelity are used. Current solutions to this problem require additional hardware and do not optimize the pulse for the final excitation profile. The proposed methodology models the amplifier with a neural network, connects the network to a Bloch simulator, and optimizes the pulses for the desired excitation profile. In simulation, a windowed sinc pulse (time-bandwidth product = 10, phase = 0 radians, duration = 1 ms) was optimized to minimize the loss between the target profile and the generated profile after the pulse passes through the amplifier to 0.05% of the starting loss.
Central SNR Gain from the Field Strength: Evaluation of Current RF Coil Technology
Authors: Sadeghi-Tarakameh Alireza , Grant Andrea , Waks Matt , Tavaf Nader , Lagore Russell , DelaBarre Lance , Auerbach Edward , Adriany Gregor , Van de Moortele Pierre‐Francois , Ugurbil Kamil , Eryaman Yigitcan
Published: August 2024

Higher signal-to-noise ratio (SNR) is the primary motivation for increasing the magnetic field strength of MRI scanners. However, advanced technology, including state-of-art radiofrequency receiver coils, is strictly required to realize the SNR gain from field strength. In this study, we experimentally investigate the capability of conventional loop technology to capture central SNR gain from field strength for head applications. For this purpose, we evaluated the SNR performance of several loop receiver arrays at 3T, 7T, and 10.5T. We showed that realizing the SNR gain from the UHF will likely require RF coil technologies other than the conventional receiver loop arrays.
Prostate Imaging at 7 Tesla: Comparison of Two 8-channel Transmit/Receive RF Local Body Arrays
Authors: May Markus , Kraff Oliver , Schulz Jenni , Orzada Stephan , Schmitter Sebastian , Meurs Thomas , van Uden Mark , Scheenen Tom , Quick Harald
Published: August 2024

The purpose of this study is to compare two different coil array designs for prostate imaging. We compared an in-house developed 8chpTx/Rx micro stripline element coil array with meanders to a recently introduced, commercially available 8chpTx/Rx coil array based on fractionated dipoles for 1H prostate imaging at 7T. Both coil arrays showed comparable results in the phantom and in vivo examinations. The commercially available coil array performs slightly better in the region of the prostate and is well suited for future prostate imaging at 7T.
Eight-channel transceiver array for combined head and neck imaging at 7 Tesla
Authors: Baskaran Divya , McElhinney Paul , Williams Sydney , Spiers Sarah , Porter David , Gunamony Shajan
Published: August 2024

Combined full brain and neck MRI has been proven inevitable in diagnosis of variety of neurodegenerative diseases such as multiple sclerosis, and amyotrophic lateral sclerosis. High spatial resolution and signal-to-noise ratio provided by the ultra-high field MRI systems (>7T) could be valuable in identification of such subtle morphologies which are not noticeable at standard MRI systems. Current state-of-the-art requires change of coil for imaging either brain or C-spine or equipped with 16-channel transmission capability. This work presents the design and validation of novel neurovascular transceiver array with 8 channels (industry standard) for combined head and neck imaging at 7T.
PASTeUR package extension to slab-selective excitations and 3D-EPI for plug-and-play parallel transmit at 7 Tesla
Authors: Jamil Redouane , Massire Aurélien , Mauconduit Franck , Gras Vincent , Naudin Mathieu , Guillevin Rémy , Pracht Eberhard , Stöcker Tony , Boulant Nicolas , Stirnberg Rüdiger
Published: August 2024

Keywords: Parallel Transmit & Multiband; High-Field MRI; RF Pulse Design & Fields; fMRI PASTeUR is a package of sequences using non-selective parallel transmission Universal Pulses (UP) as a plug-and-play pTX solution alleviating B1+ inhomogeneities. Here, we extend the UP solution to slab-selective excitations while preserving a plug-and-play philosophy. A slab of any thickness/orientation/rotation can be acquired without subject-specific calibrations. In vivo experiments performed with an fMRI protocol on a 3D-EPI show that the improved B1+ homogeneity can result in higher SNR. Moreover, the slab-selective UP coupled with parallel imaging and segmented k-space acquisitions pushed further the quality of 3D-EPI.
Partial Volume Averaging of Diffusion Tensor Imaging in the Fornix
Authors: Sakaie Ken , Nemani Ajay , Lowe Mark , Koenig Katherine
Published: August 2024

Diffusion Tensor Imaging of the fornix promises to serve as an imaging biomarker for cognitive decline in multiple sclerosis and Alzheimer’s disease. As the fornix is surrounded by cerebrospinal fluid in the lateral ventricles, partial volume averaging can bias measures of tissue microstructure. Here, we use a high spatial resolution, multishell acquisition to test the methods for combating partial volume averaging in the fornix.
Distinguish Injured from Intact Axons in Coherent Fiber Bundles Using Network Estimation Operator (NEO)
Authors: Blum Jacob , Lin Tsen-Hsuan , Rim Donsub , Song Sheng-Kwei
Published: August 2024

Deep Neural Network based Network Estimation Operator (NEO) was developed to differentiate and quantify parallel fibers of different axial diffusivities. Data from both Monte Carlo simulations and an In-Silico imaging phantom were analyzed by both DBSI and NEO. Results reveal that NEO distinguished parallel fibers of different axial diffusivity while DBSI only identified a single fiber. NEO can detect and quantify injured vs. non-injured axons in a coherent fiber bundle. Thus, NEO can quantify the extent of axonal injury and loss more accurately than DBSI and other advanced diffusion MRI models.