bluuebunny/crossref_metadata_2025 huggingface dataset:
Age-related time-dependent diffusivity changes within healthy human prostate
Authors: Ma Xiao , Seres Peter , Kinnaird Adam , Fung Christopher , Feiweier Thorsten , Beaulieu Christian
Published: August 2024

Diffusion MRI is used daily in prostate cancer diagnosis. Modification of the diffusion time can probe alterations in prostate microstructure dimensions that may occur with aging or cancer. The mean diffusivity (MD) difference between ‘long’ diffusion time stimulated echo acquisition mode (STEAM) and ‘short’ diffusion time oscillating gradient spin echo (OGSE), and between STEAM and ‘medium’ diffusion time pulsed gradient spin echo (PGSE) showed significant positive linear correlation versus age in peripheral zone of healthy adult prostate (n=15); however, this correlation was not identified in the central gland. Diffusion time sensitivity could reveal age-related prostate tissue microstructural remodeling.
Tractography of the subcortical U-fibers using a position-dependent maximum angle
Authors: Delinte Nicolas , Dessain Quentin , Dausort Manon , Bulcke Colin Vanden , Macq Benoit
Published: August 2024

Short association fibers in the subcortical white matter, also known as U-fibers, represent the connections between neighboring gyri. Due to the geometry of the cortical folds and the sharp turns along the cortical surface, tractography of U-fibers remains a challenge since increasing the maximum angle between tractography steps also increases the occurence of false positive streamlines. We propose to replace the fixed maximum angle value in tractography algorithms by an angular map, allowing higher angles at the interface between grey and white matter. This enables a more accurate tracking of U-fibers, while keeping a low number of false positive streamlines.
Relationship Between Fractional Anisotropy and Negative Susceptibility from Single-orientation Magnetic Susceptibility Separation
Authors: Kan Hirohito , Uchida Yuto , Ueki Yoshino , Kasai Harumasa
Published: August 2024

The magnetic source separation method can estimate contributions of diamagnetic myelin and paramagnetic iron in the white matter using solely gradient-echo data in white matter. This study determined the relationship between negative susceptibility (χ-) and fractional anisotropy as a myelin-sensitive biomarker and compared with the conventional susceptibility (χ) in young healthy volunteers. There was a significant negative correlation between the χ- and FA. In contrast, the conventional χ has a weaker correlation to the FA than the χ- result. However, the χ- in white matter represented the non-monotonic fiber orientation dependence on the B0 field.
Brain susceptibility and oxygen extraction fraction relate to cognition altered by white matter hyperintensity in cognitively normal elderly
Authors: Chen Lin , Soldan Anja , Lin Zixuan , Oishi Kumiko , Oishi Kenichi , Faria Andreia , Albert Marilyn , van Zijl Peter , Li Xu
Published: August 2024

We investigated associations of brain iron as measured by QSM, global oxygen extraction fraction (OEF) as measured by TRUST and white matter hyperintensity (WMH) as measure by FLAIR, and their possible interactive effects on both global composite and domain-specific cognitive functions in cognitively normal participants. Significant associations were observed between global WMH burden and tissue susceptibility suggesting contributions from small vessel diseases to tissue iron deposition. Negative associations between tissue susceptibility and cognition as well as positive associations between OEF and cognitive performance were observed within participants with low WMH burden, but not as significant in high WMH group.
Depiction of Small Vessels in QSM is Influenced by Regularization Parameter in TGV-Regularized Parallel Image Reconstruction
Authors: Jaffray Alexander , Bartels Lara , Kames Christian , Rauscher Alexander
Published: August 2024

Quantitative susceptibility mapping is a possible modality with which to measure and identify diseases involving small vasculature in the brain. However, multi-echo gradient echo images that are a requirement for high quality quantitative susceptibility map reconstruction require long scan durations, limiting clinical utility. This duration can be reduced with the use of parallel imaging strategies, and non-linear reconstruction with total generalized variation regularization is an increasingly popular strategy for undersampled reconstruction. We demonstrate that the depiction of small vessels and surrounding structures in QSM is significantly sensitive to the choice of regularization parameter used in the reconstruction.
Imaging the cerebral cortex and substantia nigra in vivo using high-resolution quantitative susceptibility mapping at 5.0-T
Authors: Zhang Ming , Gao Lanlan , Zhang Shuheng , Wei Hongjiang
Published: August 2024

It is challenging to resolve the human brain microstructure using MRI due to limited SNR and poor image contrast. High-resolution quantitative susceptibility mapping (QSM) at an ultra-high magnetic field could be a useful tool for revealing the subtle structure of the brain due to intrinsic susceptibility differences between tissues. In this study, the six-layer laminae of the cerebral cortex and swallow-tail sign of SN were successfully resolved using high-resolution QSM at 5.0-T. The preliminary result could indicate the potential of high-resolution QSM for investigating the subtle structures of the human brain and related brain disorders.
Convolutional-neural-network-based denoising with estimated noise-based normalization to effectively reduce noise for various noise levels
Authors: Suzuki Atsuro , Amemiya Tomoki , Kaneko Yukio , Yokosawa Suguru , Shirai Toru
Published: August 2024

To develop a convolutional neural network (CNN)-based denoiser for various noise levels, we propose the use of estimated noise-based normalization in denoising. When the CNN-based denoiser with estimated noise-based normalization was applied to brain FLAIR images with various noise levels, it resulted in values closer to the normalized root mean square error (NRMSE) between the denoised and the target images compared with a conventional CNN-based denoiser trained with the same noise level as that in the input image. In conclusion, our method effectively reduced the noise in an image with various noise levels in terms of minimization of the NRMSE.
Clinical assessment of a deep learning-based denoising method for DWI of Nasopharyngeal Cancer
Authors: Meng Tiebao , Liu Haibin , He Haoqiang , Zhang Jialu , Qian Long
Published: August 2024

Deep Learning reconstruction (DLR) has the potential to reduce MRI scan time while improving signal-to-noise ratio (SNR) and maintaining spatial resolution. This study evaluated results of DLR in 66 patients undergoing clinical DWI of nasopharyngeal cancer (NPC). To assess the image quality of the DWI with DLR, each patient underwent three different protocols: conventional DWI without DLR, fast DWI without DLR and fast DWI with DLR. The image quality was evaluated among these groups. Preliminary results suggested the feasibility of fast DWI with DLR in the diagnosis of NPC with reduced scan time.
Patient-specific Self-supervised Resolution-enhancing Networks for Synthesizing High-resolution Magnetic Resonance Images
Authors: Yang Xiaofeng , Mandava Sagar , Lei Yang , Xie Huiqiao , Wang Tonghe , Roper Justin , Liu Tian , Mao Hui
Published: August 2024

This study aims to develop an efficient and clinically applicable method using patient-specific self-supervised resolution-enhancing network to synthesize the high-resolution information of MR images in the low-resolution direction to generate respective high-resolution MRI.
Elevated Muscle Water T2 in Dystrophinopathy
Authors: Walter Glenn , Barnard Alison , Forbes Sean , Willcocks Rebecca , Baetscer Eric , Triplett William , Rooney William , Vandenborne Krista
Published: August 2024

Both MRI and MRS measures reveal that water T2 can be elevated in individuals living with dystrophin deficits, which includes patients with DMD, BMD and manifesting carriers. This has important implications when evaluating therapeutics aimed at decreasing inflammation (e.g., corticosteroids or NFkb inhibitors) or disease modifying interventions, such as gene therapies.
Quantification of lumbar paraspinal muscle injury in patients with low back pain using intravoxel incoherent motion diffusion weighted imaging
Authors: Liu Yinqi , Liu Weiyin , Zhang Kun
Published: August 2024

Chronic low back pain (CLBP) has been reported to be associated with lumbar paraspinal muscles injury. Lumbar paraspinal muscles injury may result from oxidative stress and inflammation. In our study, D* at the middle of L4 and L5 levels of the paraspinal muscles was significantly higher in LBP group than in HCs. The fluid oozing from the inflammation can lead to greater unrestricted molecular movement. Therefore, non-invasive and contrast-agent-free IVIM could be a good perfusion predictor of lumbar paraspinal muscle injury.
Exercise-induced changes of macromolecular content in calf muscles quantified with T1ρ magnetic resonance imaging
Authors: Li Yanbin , Ni Chang , Wang Jialin , Lv Zhenfeng , Mu Xin , Wu Mingyan , Qi Haikun , Zhang Jeff L.
Published: August 2024

Exercise could induce changes in skeletal muscle’s macromolecular content. In this study, we used an exercise-then-imaging protocol to verify and characterize such phenomenon for calf muscles of healthy subject. A T1ρ mapping technique was used for imaging calf muscles before and after planter flexion of different loads. It was found that post-exercise increases in T1ρ values of gastrocnemius and peroneus longus at exercise load of 16 and of 20 lbs were significantly higher than that of 8 lbs. In conclusion, T1ρ is sensitive to changes of macromolecular content in calf muscles induced by plantar flexion of moderate or high intensity.
Enhanced Precision of the OXPHOS Measurement with integrated CrCEST MRI and Down Field Proton MR Spectroscopy
Authors: Kumar Dushyant , Armbruster Ryan , Benyard Blake , Nanga Ravi , Wilson Neil , Reddy Ravinder
Published: August 2024

Creatine recovery time constant (τCr) of exercised muscle is strongly coupled to net mitochondrial oxidative phosphorylation. However, local in vivo pH drop plays the role of a potential confounder, leading to significantly slower creatine recovery. Even under the same prescribed exercised regime, the extent of acidification and hence its impact on τCr would be variable across participant. To the best of our knowledge, this is the first study where downfield 1H-MR spectroscopy and 3D creatine chemical exchange saturation transfer are extensively used to prescribe mild exercise regime in terms of maximal voluntary contraction of participants while avoiding any acidification.
Diffusion Tensor Imaging of Swimmers’ Supraspinati: Fiber Distinctions Between Sprint and Distance Freestyle
Authors: Shoults Grant , Gold Evan , Kogan Feliks , Mazzoli Valentina
Published: August 2024

Knowledge surrounding post-injury supraspinati in swimmers is vast, however a deep, preventative understanding at the cellular and fiber level is lacking. Through DTI, sixteen elite college swimmers were analyzed to evaluate mechanically stress induced differences between sprint and distance freestylers. Significant results (p-value<0.05) were found between groups for λ1, λ2, λ3, RD, MD, and volume. Findings indicated sprinters having a significantly larger MD and RD which was not compatible with the heightened levels microtrauma associated with aerobic distance training. DTI’s ability to inspect microstructural characteristics may pose it as an addition tool to conventional imaging techniques for athletes.
Quantitative evaluation of gluteal and multifidus muscle atrophy and fatty infiltration in patients with lumbosacral nerve root compression
Authors: Yin Shi , Weiqiang Dou
Published: August 2024

This study aims to investigate if MR technology can be applied to quantitatively evaluate the atrophy and fatty infiltration of gluteal and multifidus muscles in patients with lumbosacral nerve root compression. By quantitative evaluating 88 patients, we found the the change of multifidus muscle is related to the level of compressed nerve root and duration. As an indirect manifestation of nerve root compression, muscle change can help diagnosis in conventional lumbar MR images. Muscle content, especially that of multifidus is suggested to be a good indicator to complete the postoperative evaluation.
Dynamic T2 mapping following muscle exercise measured by fast spin-echo and ultrafast spin-echo EPI
Authors: Ryu Jaekyun , Jung Won Beom , Otgonbaatar Chuluunbaatar , Park Jinil , Kim Juho , Song Jeonghak , Shim Hackjoon
Published: August 2024

The changes in T2 driven by water content, oxygenation, pH, and blood volume in tissue altered during intense physical activity provides chance to measure the muscle performance. In this study, we investigated feasibility of dynamic T2 measurement for exercise-induced thigh muscle activity using conventional fast spin-echo (FASE, Fast Advanced Spin Echo) and ultrafast spin-echo EPI (SE-EPI) with 3T MRI.
Longitudinal quantitative imaging of skeletal muscles and peripheral nerves in CMT1A patients using Double-Echo in Steady-State at 7 Tesla
Authors: Sveinsson Bragi , Barry Robert , Rosen Matthew , Sadjadi Reza
Published: August 2024

Charcot-Marie-Tooth (CMT) is a neuromuscular disease causing progressive loss of muscle mass and function as well as nerve damage. Quantitative MRI offers the ability to investigate the condition of nerves and skeletal muscle non-invasively. In this work, we report findings from measuring various quantitative neuromuscular metrics in four CMT1A patients in high-resolution images obtained at 7T, measured at two time points.
Magnetic resonance fingerprinting thermometry (MRFT) versus PRFS thermometry: comparative temperature prediction in ex vivo bovine muscle
Authors: Qian Enlin , Poojar Pavan , Fung Maggie , Jin Zhezhen , Vaughan John , Shrivastava Devashish , Gultekin David , Geethanath Sairam
Published: August 2024

We explored T1-based magnetic resonance fingerprinting thermometry (MRFT) and compared it with proton resonance frequency shift (PRFS) thermometry in ex vivo bovine muscle data. We conducted temperature sensitivity calibration experiments for both methods. We compared MRFT and PRFS thermometry predicted temperatures in bovine muscles, validated by fluoroptic probe measurements. We observed strong correlation in temperature sensitivity calibration experiments (R2>0.958). Both methods predict temperature accurately (RMSE<1.37 ℃ and RMSE<0.93 ℃ for MRFT and PRFS, over a range of 25 ℃). We observed strong correlation between PRFS and MRFT predicted temperature in heated bovine muscle (R2>0.93).
Effect of conductor width on coil array coupling
Authors: Zhao Yunkun , Zhang Xiaoliang
Published: August 2024

This study investigates the effect of conductor width of the RF coils to the EM coupling of an array. The results show that the wide conductor of the RF coils offers less EM coupling among resonant elements.
Development of Head and C-Spine coils for use at 7T
Authors: Sidhu Jagjit , Smerglia Alexander , Petropoulos Labros , Zheng Tsinghua , Yang Xiaoyu , Tatulinski Jami , Sakaie Ken , Taylor Paul , Lowe Mark
Published: August 2024

MR imaging at 7T provides a greater signal intensity, which yields some combination of a greater signal-to-noise ratio, smaller voxel size, and/or faster scan times compared with lower field strengths. However, there remains room for improvement at 7T in terms of image homogeneity and a limited selection of coils. In this work, we summarize ongoing efforts to develop a single-transmit (STX) cervical spine (C-spine) and a parallel transmit (PTX) head coil. Both coils have a more open design with detachable anterior halves and larger physical dimensions.
Improved Transmit Efficiency and Clinical Coverage using a Cervical Spine Array with a Volumetric Transmitter at 7T
Authors: Smerglia Alexander , Petropoulos Labros , Tatulinski Jami , Zheng Tsinghua , Yang Xiaoyu , Sidhu Jagjit , Sakaie Ken , Lowe Mark
Published: August 2024

Several challenges are present when imaging the cervical spine in high-field MRI, such as achieving B1 coverage over the desired anatomy while maximizing efficiency of the transmitter. A cervical spine array coil with a volume transmit birdcage was built and tested on a system for improved transmit coverage and efficiency over previous prototypes. The coil consists of a partially shielded 22-rung birdcage transmitter and a 24 element receive RF array. A new mechanical design with larger eye windows improves the clinical experience. Improved transmit efficiency and complete B1 field coverage in the cervical spine region were confirmed through volunteer imaging.
Uniformity Improvement of the 7T Body MR Images
Authors: Park Bu , Rajan Sunder
Published: August 2024

To optimize MR image quality of 7T Body, the image region is divided into multiple ROIs, which can be independently optimized using transmit array optimization techniques to improve image intensity. Compared to the results of quadrature driving method, mean and SD of |Mt| in the full image (inner diameter of 500 mm) were improved 47% (Mean) and 48% (SD), whereas 94% (Max) and 97% (Mean) improved in the unaveraged SAR using the proposed method. The proposed method using multiple independently optimized ROIs and numerical simulations significantly improved uniformity of |Mt| body images at 7T. Keywords: 7T Body, Uniformity, SAR
Inductive and capacitive coupling modes of an RF coil to an ultra-High Dielectric Constant (uHDC) disk resonator
Authors: Lotfi Parisa , Soon Soo-Han , Gandji Navid P. , Lanagan Michael , Wiesner Hannes M. , Zhu Xiao-Hong , Chen Wei , Yang Qing X
Published: August 2024

We investigated capacitive and inductive couplings of an RF coil to an ultra-High Dielectric Constant (uHDC) disk resonator with a given resonance mode of similar frequency using simulation and experiments. Coupling of the RF coil and uHDC resonator can result in splitting the resonance into two modes: a parallel mode via inductive coupling and an anti-parallel mode via capacitive coupling. With the two resonators, the stronger and deeper penetration of the resultant B1 field is observed with parallel mode (in-phase) than anti-parallel mode (out-of-phase), which supports that the parallel mode is preferable for coupling uHDC resonators for MRI applications.
Proof of concept for auto-resonant structure to increase the field of view of surface coils
Authors: Dubuc Camille , Thibault Clément , Boussaha Faouzi , Marhabaie Sina , Ginefri Jean-Christophe , Poirier-Quinot Marie
Published: August 2024

To improve the performances of High Temperature Superconducting surface coils, it is essential to enlarge their field of view while keeping the sample-induced noise low. New multi-loop designs could help meeting this challenge. In this work, we present a preliminary study on a copper coil. We first introduce the design, electromagnetic simulations, realization of a multi-loop transmission line resonator copper coil and experimental characterizations. Signal to Noise Ratio-maps of the coil are then acquired in a 3T field.
SNR Improvement with Ultrahigh Dielectric Constant (uHDC) Material for 7T 1H MRS Imaging
Authors: Jayatilake Mohan , Sica Christopher , Karunanayaka Dhevin , Ekanayaka Anupa , Ahmed Biyar , Elyan Rommy , Karunanayaka Prasanna
Published: August 2024

We investigated the effects of ultra-high dielectric constant (uHDC) materials for enhancing the B1 field at 300 MHz for potential MRS imaging 1H at 7.0 T. The uHDC material was able to increase the transmit efficiency. We calculated B1+ and B1+ efficiency for a phantom mouse brain with and without uHDC material and empirically obtained nominal flip angle maps and 1H metabolic spectra with and without uHDC. Our results show significant enhancement of Signal-to-Noise ratios (SNRs) of 1H spectra in the presence of the uHDC material.
Blood plasma metabolomics study of metastases prostate cancer patients reflects liver alterations involving carbon and nitrogen metabolism
Authors: Kumar Pradeep , Kumar Rajeev , Thulkar Sanjay , Sharma Sanjay , Khan Maroof , Kumar Virendra
Published: August 2024

Prostate cancer (PCa) with metastases remains incurable diseases requiring early diagnosis and effective treatments. To investigate and integrate the blood plasma metabolomic profiles with clinical parameters to distinguish PCa patients with metastasis from those without bone metastasis using 1H-NMR spectroscopy for establishing potential biomarker/s. Significant changes in liver enzyme ALP, ALT, and AST levels were observed in metastatic PCa. Pathway analysis revealed dysregulation of nitrogen and carbon metabolism. The discovery of metabolites in blood associate with clinical parameters for understanding PCa related pathophysiological mechanisms of bone and liver metastases.
A Preliminary study of Idiopathic Pulmonary Fibrosis using 3D ventilation map based on 3D Ultrashort Echo time Imaging
Authors: Lee Seokwon , Lee Ho Yun , Park Hye Yun , Yoo Hongseok , Park Jinil , Kim Hyonha , Park Jang-Yeon
Published: August 2024

Idiopathic pulmonary fibrosis (IPF) is a specific form of idiopathic interstitial pneumonia of unknown cause, the most common and fatal of these interstitial lung diseases. A study on the quantitative assessment of IPF severity based on signal intensity in hyperpolarized MRI lung imaging has recently been proposed. In this preliminary study, it was shown that non-contrast-enhanced 3D ultrashort echo-time (UTE) MRI could diagnose ventilation defects in lesions in patients with IPF using UTE-based 3D ventilation maps and histograms in combination with 3D UTE structural images.
Intravoxel incoherent motion diffusion-weighted imaging of solitary pulmonary lesions: initial study with gradient-and-spin echo (GRASE)
Authors: Lv Siqiang , Sun Zhanguo , Yue Xiuzheng
Published: August 2024

Intravoxel incoherent motion diffusion-weighted imaging (IVIM) could obtain parameters of pure water molecule diffusion and microcirculatory perfusion-related diffusion and more accurately reflects the complexity of the microstructure of the tumor tissues. Gradient-and-spin echo (GRASE), incorporating the gradient echo and spin echo techniques, is a fast-imaging sequence with potential for improved IVIM examinations. The aim of the study was to evaluate the feasibility and image quality of the GRASE-IVIM sequence in evaluating solitary pulmonary lesions (SPLs) by comparing with the EPI-IVIM and TSE-IVIM sequences. Our data showed GRASE-IVIM sequence could be a fast and stable alternative technique to evaluate the SPLs.
MRI-based scoring model to predict massive hemorrhage during dilatation and curettage in patients with cesarean scar pregnancy
Authors: Yang Fengleng , Jing Huaibo , Wang Xiaodan , Wang Zhigang
Published: August 2024

Cesarean scar pregnancy is a special type of ectopic pregnancy for which dilatation and curettage (D&C) is one of the main treatment modalities, and uncontrollable hemorrhage is a more dangerous complication during D&C. Accurate preoperative prediction of the risk of intraoperative hemorrhage will help gynecologists draw up precise treatment. The aim of this study is to develop an MRI scoring model for predicting intraoperative hemorrhage during D&C. The study found that cesarean section diverticulum area, uterine scar thickness and gestational sac diameter were independent risk factors for intraoperative hemorrhage. A scoring model was developed, The model possessed decent prediction performance.
APTw Combined With Multiple Models DWI of Endometrial Cancer: Correlations Between Multimodal Parameters and HIF-1α Expression
Authors: Changjun Ma , Shifeng Tian , Ailian Liu , Lihua Chen , Liangjie Lin , Xiaoxiao Zhang , Yinghua Guo , Jiazheng Wang
Published: August 2024

HIF-1α is a major transcriptional factor regulating gene expression under hypoxic conditions. The identification of HIF-1α expression is very helpful for the quantitative assessment of tumor hypoxia, on which the therapeutic response is predicted or regimens are adjusted .
Multi-shell versus single-shell cardiac diffusion imaging
Authors: Elsaid Nahla , Peters Dana , Galiana Gigi , Sinusas Albert
Published: August 2024

Myocardial infarction (MI) remains a leading cause of morbidity and death in the Western world. MI causes regional dysfunction, which places remote areas of the heart at a mechanical disadvantage resulting in long-term adverse left ventricular (LV) remodeling and congestive heart failure (CHF). While the cardiac fiber structure has been the topic of study for decades, to this day, it has not been fully understood. There is a need for a deeper understanding of the normal and pathological myocardial structure. Standard techniques using diffusion tensor imaging (DTI) which typically needs one b-value (single shell) set of data, yield poor quality data, as DTI is incapable of delineating fibers that form torsions and complex interdigitation. However, multi-shell diffusion magnetic resonance imaging (dMRI) can delineate these complex fibers. This research investigates the difference between multi-shell versus single shell on the quality of the resulting cardiac tractography applied to an ex vivo normal porcine heart.
Wideband bright- and black-blood late gadolinium enhancement imaging for patients with cardiac implantable electronic device
Authors: Gut Pauline , Cochet Hubert , Sacher Frederic , Jaïs Pierre , Stuber Matthias , Bustin Aurélien
Published: August 2024

Conventional LGE PSIR provides very good contrast between healthy and scar tissue, but scar patterns may be confused with blood signal. Joint LGE bright- and black-blood imaging allows for improved scar contrast and detailed cardiac anatomy. However, many patients with cardiac implantable electronic device (CIED) do not undergo cardiac imaging due to severe hyperintensity artefacts. Here we propose a technology to image myocardial scars with unprecedent scar contrast in patients with CIED by combining bright- and black-blood SPOT imaging with wideband MRI. We showed that wideband SPOT can suppress CIED-related hyperintensity artefacts, while maintaining improved scar contrast and localization.
Trading Off Averages and Directions for Cardiac Diffusion Tensor Imaging
Authors: Cork Tyler , Hannum Ariel , Middione Matthew , Ennis Daniel
Published: August 2024

The objective of this work was to control the total number of collected diffusion weighted images (DWI) across several different acquisition schemes to evaluate which combination of directions and averages provides the highest quality data. In vivo cDTI data was collected in volunteers (N=5) using a series of fixed duration protocols that span a range of diffusion directions and signal averages. We found that balancing the number of diffusion directions (12-20) and averages (5-3) allows for robust quantification of mean diffusivity, fractional anisotropy, and helix measurements in a fixed scan time.
Evaluation of reliability and self-consistency of compartment size-distribution estimations by oscillating gradient spin-echo sequences
Authors: Gimenez Melisa , Pérez Leonardo Pedraza , Álvarez Gonzalo
Published: August 2024

Changes in tissue microstructure are promising biomarkers of neurological diseases. However, achieving robust and reliable, non-invasive diagnostic tools to estimate microstructural features is a major challenge. We perform a systematic analysis using Non-uniform Oscillating Gradient Spin Echo (NOGSE) sequences to estimate size distributions of white-matter phantoms. We evaluate the reliability and self-consistency of the inference method. We find that estimation of the distribution’s mode is very robust and reliable for sharp and smooth gradient modulations. These results contribute to developing reliable diagnostic tools based on quantitative images of tissue microstructure.
An open-source echo-planar imaging sequence for hyperpolarized 13C MRI
Authors: Blazey Tyler , von Morze Cornelius
Published: August 2024

HP 13C MR imaging in humans has largely been restricted to GE scanners. To facilitate a human HP 13C imaging program at our institution and expand the translational potential of HP 13C MRI in general, we have developed a 3D symmetric EPI sequence for imaging HP 13C agents on Siemens scanners. Sequence development was performed using Pulseq, a flexible open-source tool for prototyping platform-agnostic pulse sequences. Metabolites were selectively excited using spectral-spatial RF pulses. Optional acceleration was achieved using partial Fourier undersampling in the slice direction. The sequence was tested using a thermally polarized phantom and a HP [1-13C]pyruvate phantom.
Efficient 13C-hyperpolarization of lactate using parahydrogen and proton exchange.
Authors: Them Kolja , Kuhn Jule , Hövener Jan-Bernd
Published: August 2024

Hyperpolarization of biological molecules1,2,3 is a promising approach for metabolic MR imaging. Hyperpolarization methods based on parahydrogen and proton exchange4,5 promise almost universal polarization of many molecules, but current polarization yields are relatively low. Here, we present a new variant of Parahydrogen-Induced Polarization relayed via proton exchange (PHIP-X), which we demonstrate using the important biomolecule lactate. Polarization transfer between labile and covalent bound protons at different fields, combined with an RF pulse sequence, enables significantly enhanced 13C polarization of lactate. We believe that this approach may be used as a general strategy for the polarization of various biomolecules.
Simultaneous Liver and Spleen Segmentation using U-Net Transformer Model on T1-weighted and T2-weighted MRI Data
Authors: Zhang Huixian , Ali Redha , Li Hailong , Pan Wen , Reeder Scott , Harris David , Masch William , Alsam Anum , Shanbhogue Krishna , Parikh Nehal , Dillman Jonathan , He Lili
Published: August 2024

To develop an AI system for precise and fully automated, simultaneous segmentation of the liver and spleen from T1-weighted and T2-weighted MRI data. Our study compares the performance of the U-Net Transformer (UNETR) and the standard 3D U-Net model for simultaneous liver and spleen segmentation using MRI images from pediatric and adult patients from multiple institutions. Our work demonstrates that the UNETR shows a statistical improvement over 3D U-Net in both liver and spleen segmentations.
A deep learning-based liver tumor segmentation algorithm in enhanced multi–phase MRI images
Authors: Dou Meng , Zhao Ying , Lin Tao , Yao Yu , Liu Ailian
Published: August 2024

In this paper, we propose a deep learning-based liver tumor segmentation algorithm in enhanced multi-phase MRI images. The experimental results show that the proposed method can segment liver and tumor in enhanced multi-phase MRI images with a smaller resource occupation, and outperforms the comparison method.
Amniotic Fluid Segmentation using Convolutional Neural Networks
Authors: Costanzo Alejo , Ertl-Wagner Birgit , Sussman Dafna
Published: August 2024

Amniotic Fluid Volume (AFV) is an important fetal biomarker when diagnosing certain fetal abnormalities. We aim to implement a novel Convolutional Neural Network (CNN) model for amniotic fluid (AF) segmentation which can facilitate clinical AFV evaluation. The model, called AFNet was trained and tested on a radiologist–validated AF dataset. AFNet improves upon ResUNet++ through the efficient feature mapping in the attention block, and transpose convolutions in the decoder. Experimental results show that our AFNet model achieved a 93.38% mean Intersection over Union (mIoU) on our dataset. We further demonstrate that AFNet outperforms state-of-the-art models while maintaining a low model size.
Breast Tumor Segmentation using U-Net with ResNet34
Authors: Jun Yunkyoung , Jeong Jiwoo , Jin Seokha , Myung Noehyun , Lee Jimin , Cho Hyungjoon
Published: August 2024

The proposed research implemented an automatic tumor segmentation application on an orthotopic breast tumor model. This application can segment the tumors accurately and monitor tumor growth and the therapeutic effect of Doxorubicin for treatment. Also, the outputs from the application can reconstruct into 3D rendering and offer the visualization of shape and volume. As a result, the application can be applied to orthotopic breast tumor model research.
Comparing the effect of body weight, BMI and physical activity intensity on calcified and uncalcified cartilage using quantitative UTE MRI
Authors: Wang Hanqi , Li Qing , Sommer Stefan , Lu Yong
Published: August 2024

UTE technique was utilized to quantitatively assess calcified cartilage (CC) and uncalcified cartilage (UC). T2* values of UC in patella, medial tibia and lateral femur positively moderately correlated with body weight, while T2* values of CC showed no significant correlation. T2* values of UC showed no significant correlation with BMI, while T2* values of CC in medial femur and lateral tibia showed negatively strong and positively moderate correlation, respectively. T2* values of CC and UC showed no significant correlation with physical activity level. The mechanical loading effect performs different between CC and UC, indicating their different bio-mechanical properties.
Orientation-independent T2 relaxation parameters and biomechanics of healthy and degenerated human articular cartilage
Authors: Leskinen Henri , Tuppurainen Juuso , Jäntti Jiri , Mäkelä Janne , Nissi Mikko
Published: August 2024

Variation in T2 relaxation has been linked to changes in articular cartilage degenerative status. Most prominently to the collagen network integrity. However, T2 is greatly anisotropic in highly organized tissues, e.g. articular cartilage. Previous results show that using re-orientation experiments, orientation-independent T2 components can be defined. This study assesses the potential of these parameters to serve as biomarkers for osteoarthritis via comparing the orientation-independent T2 parameters to biomechanical testing results in human articular cartilage. Changes in the anisotropic component of T2 in the superficial and transitional zones are observed along with the biomechanical degeneration of the articular cartilage.
Improved identification of cartilage lesion in chondromalacia patellae (CMP) with 7.0 T MRI compared with 3.0T MRI: a preliminary study
Authors: Wang Yan , Huang Jiayu , Qu Jianxun , Bian Xiangbing , Duan Caohui , Li Chunbao , Zhang Jing , Lou Xin
Published: August 2024

To compare the ability in revealing subtle changes of patellar cartilage in suspected CMP between 7.0T and 3.0T MRI. We documented the total number of identified cartilage lesions by two radiologists and compared the number of cartilage lesions identified between 3.0T and 7.0T MRI. The result showed good consistency between readers. The mean number of cartilage lesions identified on 3.0T images was significantly less than 7.0T images. Considering the preliminary and small-sample feature of the study, we conclude conservatively that compared with 3.0T MRI, 7.0T MR images reveal more lesion of the patellar cartilage in CMP patients.
CRLB minimization for optimal Multi Spin-Echo T2-mapping of the cartilage using dictionary-based estimation
Authors: Fernandes Tiago Timoteo , Geethanath Sairam , Nunes Rita G
Published: August 2024

. We compared Cramer-Rao Lower Bounds of Multi Spin-Echo sequences’ derived T2 values using a dictionary approach for musculoskeletal relaxometry. The refocusing flip angle, inter-echo spacing and echoe number were varied, constraining the B1+rms to 5μT and the exam time to 9 minutes, keeping TR to a minimum. Designed sequences were tested in NIST/ISMRM phantom and ex vivo, and compared against the vendor’s MSE. A repeatability study was performed during 5 days. An optimized sequence with target T2 value (45ms), representative of the cartilage, scored below 10% for Within-case Coefficient of Variation in 9 out of 14 vials.
RADIOMICS FEATURES OF INFRAPATELLAR FAT PAD ASSOCIATED WITH POST-TRAUMATIC OSTEOARTHRITIS AT 10+ YEARS AFTER ACL RECONSTRUCTION
Authors: Khan Sameed , Lartey Richard , Obuchowski Nancy , Gaj Sibaji , Kim Jee Hun , Li Mei , Eck Brendan , Winalski Carl , Altahawi Faysal , Jones Morgan , Huston Laura , Harkins Kevin , Knopp Michael , Kaeding Christopher , Spindler Kurt , Li Xiaojuan
Published: August 2024

ACL injury is a major risk factor for post-traumatic osteoarthritis (PTOA), however mechanisms are not fully understood. In this work, we use radiomics from quantitative MRI imaging to associate subvisual changes in the infrapatellar fat pad (IPFP) to both symptomatic and radiographic PTOA. MRI was collected from 113 patients at least 10 years post-ACLR. 1690 radiomics and 11 clinical features were extracted and selected using a gradient-boosted decision tree classifier model. A subset of texture-associated features of IPFP and no clinical features were associated with symptomatic PTOA with an AUROC of 0.74 and radiographic PTOA with an AUROC of 0.84.
Dephased bSSFP for the Delineation of Interventional Devices
Authors: Faust Jonas , Speier Peter , Krafft Axel , Patil Sunil , Ladd Mark , Maier Florian
Published: August 2024

Dephased MRI, e.g., used for the delineation of metallic interventional devices, is the reconstruction of images from a shifted k-space and can be achieved by introducing additional “White-Marker” magnetic field gradient moments into the acquisition scheme. A prototype 3D radial sequence was implemented to analyze and compare the artifact of a biopsy needle in a gel phantom for dephased GRE and dephased bSSFP contrast. We found dephased bSSFP to show improved artifact symmetry in comparison with dephased GRE. Undesired signal attributed to fat tissue interfaces in an ex-vivo phantom was successfully suppressed by introducing an altered bSSFP phase cycling.
Passive Device Tracking for interventional MRI with Ferric Ion Chelated Natural Melanin Nanoparticles
Authors: Baysoy Engin , Kaleli-Can Gizem , Özcan Alpay , Liu Chunlei
Published: August 2024

Natural melanin nanoparticles (MNPs) labeled with paramagnetic ions provide a potential MRI contrast enhancing material alternative to current MRI contrast agents due to their biocompatibility, biodegradability, metal, and biomolecule chelation properties. In this study, we investigated T1 shortening effect of Fe3+ chelated MNPs solution compared to gadolinium-based contrast agents under 3T MRI. Then, we examined traceability of MNP-Fe3+ ions deposited interventional nitinol guidewire in MR scans. Results clearly showed that the coating of Fe3+ chelated MNPs over the surface of MRI compatible instruments will increase traceability of interventional devices in MRI.
Development and Evaluation of an MR-visible Interventional Microcatheter
Authors: Kilbride Bridget , Moore Teri , Martin Alastair , Wilson Mark , Hetts Steven
Published: August 2024

Intra-arterial chemotherapy following blood-brain barrier opening (BBBO) can be a highly effective therapeutic delivery mechanism when treating primary and metastatic disease in the brain. Osmotic blood-brain barrier disruption has long been performed under x-ray guidance but has yet to gain clinical traction partially due to outcome variability. MRI is advantageous for its superior soft tissue contrast and real-time perfusion territory validation. We propose a passive microcatheter to provide real-time feedback of catheter positioning during BBBO under MRI guidance. In a phantom, we quantitated susceptibility artifacts at 3T. The catheter showed promise as a new MRI-visible tool to enhance BBBO procedures.
3D Printed Alignment Apparatus for Retrofitted Rodent PET-MRI at 9.4 Tesla
Authors: Marecki Leo , Pol Suyog , Zivadinov Robert , Schweser Ferdinand
Published: August 2024

We developed a retrofitted alignment apparatus that attaches to the MRI’s motor-driven automated positioning system and enables simultaneous preclinical PET/MRI at 9.4T with a stand-alone microPET ring. The system leverages 3D printing technology to achieve stable alignment between the two modalities, consistent placement of animals, and rapid reconfiguration between PET-MRI and MRI-only experiments. Thereby addressing the shortcomings of other retrofitted designs and proving simultaneous PET-MRI capabilities at a reduced cost.
Direct Detection of Peak-like Magnetic Field Fluctuations using Rotary Excitation (REX) based MRI
Authors: Albertova Petra , Gram Maximilian , Blaimer Martin , Schindelhütte Magnus , Kampf Thomas , Jakob Peter , Nordbeck Peter
Published: August 2024

With spin-locking, the resonance of the spin system can be shifted adjustably to the low frequency range for detection of biomagnetic field oscillations. In this study, we demonstrate that spin-locking is also sensitive to peak-like magnetic field fluctuations with broader spectral width. Simulations and measurements demonstrate that, in addition to the application of imaging neural oscillations, the spatially resolved detection of biomagnetic peaks is possible. Initial results show a high agreement between simulations and experiments and mark a first step towards spin-lock based diagnostics of biomagnetic activity, e.g. imaging of the cardiac conduction system.
Tailored cost functions for improved static pTX-based B1+ shimming in 7T cardiac MRI.
Authors: Terekhov Maxim , Lohr David , Aigner Christoph , Dietrich Sebastian , Schmitter Sebastian , Schreiber Laura
Published: August 2024

Parallel transmit (pTX) technology is an emerging tool for improving of the B1+-field homogeneity in cardiac MRI (cMRI) at the ultra-high magnetic field. In this work, we propose a methodology to enhance the characteristics of the shaped B1+ field using a tailored cost function for the optimization procedure computing complex transmit vectors of magnitudes and phases for driving TX array. Using the cost functions (CF) based on the local B1 gradients with fine-tuning by weighting coefficients allows for considerable improvement of static pTX B1-shimming quality in compared to traditional CF using the coefficient-of-variation (CoV) of B1.
Optimisation of pulse-specific phase schedule reduces peak RF amplitude in multiband parallel-transmit pulses
Authors: Ding Belinda , Williams Sydney , Zhang Minghao , Herrler Jürgen , Liebig Patrick , Dragonu Iulius , Neji Radhouene , Rodgers Christopher , Porter David
Published: August 2024

Multiband(MB) imaging can greatly reduce scan time, but MB pulses often encounter peak amplitude constraints. An optimal phase schedule has been published for traditional single-transmit (sTx) RF pulses. However, after an initial evaluation, we found that it only has marginal benefits for parallel-transmit (pTx) pulses. We compared four common optimisation algorithms (fmincon, fminsearch, simmulated annealing, global search) to determine the most suitable algorithm for choosing the best offset phases for a pTx pulse. Overall, fmincon efficiently selected the optimal phase schedule of a pTx pulse and lowered peak amplitude by an average of 15% when MB-factor=3.
Slice-specific B1 shimming can improve the repeatability of multi-shot, diffusion-weighted imaging at 7T
Authors: Ding Belinda , Williams Sydney , Dragonu Iulius , Herrler Jürgen , Allwood-Spiers Sarah , Liebig Patrick , Porter David
Published: August 2024

Parallel transmission (pTx) can significantly improve readout-segment EPI (rsEPI) diffusion-weighted imaging (DWI) at 7T when compared to the non-pTx sequence. However, no study has been done to assess the repeatability of pTx-DWI. Thus, we conducted a test-retest study to evaluate the impact pTx pulses have on the repeatability of ADC measures in a rsEPI[DP1] DWI sequence at 7T. Overall, pTx-DWI had higher SNR and can potentially improve the repeatability for intra- and inter-session ADC measures even when different B1-shim coefficients are used for different sessions. This suggests that pTx has an important role in quantittaive imaging studies at 7T.
Feasibility of an optimized B0 passive shim helmet based on iron-oxide nanoparticle inks for human brain imaging
Authors: Vanduffel Hanne , Arango Nick , Gsell Willy , Himmelreich Uwe , Vanduffel Wim , Parra Cesar , Bilgic Berkin , Cooley Clarissa , Sakellariou Dimitios , de Oliviera SIlva Rodrigo , Wald Lawrence , Ameloot Rob , Stockmann Jason
Published: August 2024

We present a new method for passive shimming based on 3D printed ferromagnetic inks that are fully compatible with the scanner RF coils. We show simulated B0 shim performance for designs that are optimized to shim the human brain for both a subject-specific passive shim insert and a robust general insert.
Robust RF Shimming With Minibatched Magnitude Least Squares Optimization
Authors: Martin Jonathan , Grissom William
Published: August 2024

We present a magnitude-least-squares RF shimming algorithm which uses interleaved noisy and locally converging updates to escape local minima and find low-cost shim solutions. We introduce noise in the algorithm by performing updates using a small minibatch of the available B1+ measurements. The method is validated using in-vivo head B1+ maps from a 7T scanner. An optimal minibatch size is found which consistently produces low-power and low-RMSE solutions across subjects and through head slices. This shim design method may be employed to more robustly correct for B1+ inhomogeneities at ultra-high field strengths than is possible with conventional methods.
Assessment and mitigation of EMI from in-room equipment in the setting of interventional 0.55T MRI
Authors: Tasdelen Bilal , Yagiz Ecrin , Ramasawmy Rajiv , Javed Ahsan , Uzun Dogangun , Yildirim Dursun Korel , Campbell-Washburn Adrienne , Nayak Krishna
Published: August 2024

Five devices that are relevant in interventional setting and a Pilot-Tone generator are assessed in terms of their electromagnetic interference with 0.55T MRI. Two of the devices (ergometer and flat-panel television) generated significant interference, however acceptable image quality was achieved when using the EDITER interference cancellation technique. EDITER also enabled the use of higher Pilot-Tone amplitudes and use of cheap, general-purpose signal generator for Pilot-Tone generation.
MRI Radiomics Model Preoperatively Predicts Key Gene Mutation in Pancreatic Ductal Adenocarcinoma Patients
Authors: Deng Yan , Zhang Xiao ming , Song Bin
Published: August 2024

Individualized management of pancreatic ductal adenocarcinoma (PDAC) is difficult and understanding it underlying biology is important. Radiomics model based on MRI was developed to predict status of KRAS and TP53 in PDAC, univariate analysis, MRMR and LASSO were applied for feature selection and multivariable logistic regression used for modeling. The classification metrics were applied to assess these models discrimination. Results suggested radiomics model based on MRI outperformed clinical model for predicting gene mutations of PDAC. This study confirmed that radiomics model based on MRI had a potentiality to predict the KRAS and TP53 mutation in PDAC.
Comparison of fat fraction techniques within the pelvis: evaluating repeatability and accuracy
Authors: Azma Yassine , Boci Nada , Abramowicz Katarzyna , Orton Matthew , Tunariu Nina , Koh Dow-Mu , Charles-Edwards Geoff , Collins David , Winfield Jessica
Published: August 2024

Dixon-derived fat fraction (FF) has proven to play a pivotal role in whole-body MRI examinations for assessment of bone marrow disease in advanced prostate cancer. However, Dixon sequences are known to be subject to multiple sources of bias compared to the proton-density fat fraction (PDFF) gold standard. In this study, FF within the pelvis was measured for healthy tissues, active lesions and treated lesions with six different Dixon sequences. All sequences demonstrated good repeatability in scan-rescan studies of healthy volunteers. Statistically significant differences were observed between T1w-FF and PDFF for both active and treated lesions which requires further investigation.