bluuebunny/crossref_metadata_2025 huggingface dataset:
Muscle magnetization transfer ratio is promising biomarker of hereditary neuropathy with liability to pressure palsy
Authors: Roth Alison , Minks Ashley , Chen Yongsheng , Li Jun , Dortch Richard
Published: August 2024

Magnetization transfer ratio (MTR) and volume of thigh muscles were investigated as imaging biomarkers in Charcot-Marie-Tooth type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsy (HNPP) patients. MTR was significantly different between HNPP and healthy control subjects; muscle volume was significantly different between CMT1A patients and healthy control subjects and HNPP patients. MTR and volume were found to be repeatable and reliable.
Association Between Ultrashort Echo-Time T2* Parameters and Clinical Outcome in an RCT of Patellar Tendinopathy
Authors: van der Heijden Rianne , Moskwa Robert , Liu Fang , Wilson John , Heiderscheit Bryan , Hetzel Scott , Stewart Zachary , Lee Kenneth , Kijowski Richard
Published: August 2024

This study was performed to investigate the association between bi-component UTE-T2* parameter of the patellar tendon and clinical pain scores over time in a randomized control trial for patellar tendinopathy (PT). The fraction of the fast-relaxing macromolecular bound water (FF) of the proximal patellar tendon and VAS pain scores were assessed at 0, 16 and 52-weeks in 29 patients with PT randomized into three treatment groups. All treatment groups showed a significant improvement (p<0.05) in pain and a significant increase (p<0.05) in FF over time, with a significant inverse correlation (p<0.05) between the increase in FF and decreased pain.
Migration of Potential Microstructural Markers of AD by High-Resolution Hippocampal Diffusion MRI
Authors: Comrie Courtney , Schatz Samantha , Johnson Kevin , Squire Scott , Chen Nan-kuei , Hutchinson Elizabeth
Published: August 2024

Diffusion MRI has been identified as a promising tool for identifying novel and early makers of AD and comorbid pathology. This study worked towards translating advanced microstructural techniques to clinical acquisitions for the purpose of potential AD diagnosis. High resolution diffusion human data was acquired using a 4-way phase-encoding and specialized hippocampal FOV in healthy subjects for method development. High quality maps were achieved that revealed more hippocampal microstructural information than what is acquired in database protocols according to preliminary results.
Radial MP2RAGE combined with binomial pulses for multi-parametric (T1 and PDFF) abdominal mapping.
Authors: Maingault François , Lefrançois William , Corbin Nadège , Trotier Aurélien , Dallet Laurence , Thiaudière Eric , Miraux Sylvain , Ribot Emeline
Published: August 2024

A 3D radial-encoding MP2RAGE sequence was developed with binomial pulses within the GRE trains. These give the possibility to obtain water-specific, fat- specific or composite 3D T1-maps of the abdominal cavity during free-breathing in less than 10 minutes. A 3D Proton Density Fat Fraction (PDFF) map can also be determined with the same scan. The T1 values are similar with the standard MP2RAGE and the PDFF correspond to the ones obtained with MR spectroscopy. A test-retest on healthy volunteers shows the good reproducibility of the method.
The Patients’ Experience on Neuroimaging of Gliomas: A Cross-Sectional Survey Study
Authors: Wamelink Ivar , Hempel Hugo , van de Giessen Elsmarieke , Vries Mark , de Witt Hamer Philip , Barkhof Frederik , Keil Vera
Published: August 2024

Glioma patient experience of MRI scans, repeated follow-up, and gadolinium-based contrast agents (GBCA) are unknown, despite the vulnerability of this patient group and relevant implications for clinics and science. This cross-sectional survey questioned 100 patients with primary brain tumors and found generally positive experiences with neuro-oncological scans. Age, diagnosis, and number of previous scans had little impact on the patient experience. However, women found MRI and intravenous injection significantly more uncomfortable. Also, patients would prefer GBCA-free MRIs if diagnostically equivalent. Patient knowledge towards GBCAs was limited and better information regarding GBCA and the MRI itself is needed.
Adaptive convolution for including a-priori information in deep learning models for quantitative susceptibility mapping
Authors: Graf Simon , Küchler Nora , Wohlgemuth Walter , Deistung Andreas
Published: August 2024

Deep learning models used for solving dipole inversion of quantitative susceptibility mapping typically lack an integration of a-priori information. We show for the first time that information of voxel-size and field-of-view orientation with respect to B0 can be incorporated into network models by deploying adaptive convolution. Various network models were trained for 170 epochs to solve dipole inversion on synthetic data with arbitrary orientation and voxel-sizes. Adaptive convolution models outperform conventional models in computing susceptibility maps from arbitrarily oriented field distributions with anisotropic voxel sizes and allows a reduction of training time.
Reducing annotation burden in MR segmentation: A novel contrastive learning loss with multi-contrast constraints on local representations
Authors: Umapathy Lavanya , Brown Taylor , Greenhill Mark , Lu J'rick , Martin Diego , Altbach Maria , Bilgin Ali
Published: August 2024

The availability of limited labeled data motivates the use of self-supervised pretraining techniques for deep learning (DL) models. Here, we propose a novel contrastive loss that pushes/pulls local representations within an image based on representational constraints from co-registered multi-contrast MR images that share similar underlying parameters. For multi-organ segmentation tasks in T2-weighted images, pretraining a DL model using the proposed loss function with constraints from co-registered echo images from a radial TSE acquisition, can help reduce annotation burden by 60%. On two independent datasets, proposed pretraining improved Dice scores compared to random initialization and pretraining with conventional contrastive loss.
SwinV2-MRI: Accelerated Multi-Coil MRI Reconstruction using Shifted Window Vision Transformers
Authors: Rahman Tahsin , Cabrera Sergio , Bilgin Ali
Published: August 2024

Vision transformers (ViT) are increasingly utilized in computer vision and have been shown to outperform CNNs in many tasks. In this work, we explore the use of Shifted Window (Swin) transformers for accelerated MRI reconstruction. Our proposed SwinV2-MRI architecture enables the use of multi-coil data and k-space consistency constraints with Swin transformers. Experimental results show that the proposed architecture outperforms CNNs even when trained on a limited dataset and without any pre-training.
MR conductivity imaging to decrease false-positive biopsy caused by breast ultrasound: comparison with DWI and abbreviated MRI
Authors: Kim Soo-Yeon , Kim Jun-Hyung , Cho Nariya , Kim Dong-Hyun
Published: August 2024

We evaluated the role of MRI as a problem-solving tool to reduce false-positive biopsy caused by breast ultrasound. Seventy nine participants underwent MRI prior to ultrasound-guided core needle biopsy. The MRI protocol consisted of T2-weighted imaging for conductivity map reconstruction, diffusion-weighted imaging, and abbreviated contrast-enhanced MRI. The conductivity, ADC, and BI-RADS criterion lowered false-positive biopsy by 23%, 38%, and 43%, respectively, while being able to detect all cancers. Conductivity imaging showed the potential but showed lower performance than diffusion-weighted imaging and abbreviated MRI in reducing unnecessary biopsies caused by breast ultrasound.
Universal pulses for the cervical spinal cord at 7T: a feasibility study
Authors: Papp Daniel , Boulant Nicolas , Massire Aurelien , Mauconduit Frank , Gras Vincent , Cohen-Adad Julien
Published: August 2024

While the Universal Pulse approach to mitigate the RF field inhomogeneity effect has been successfully deployed in brain imaging, adoption in spinal cord imaging is lacking. Here, we demonstrate the feasibility of designing Universal Pulses for the cervical spinal cord at 7T, and show a marked improvement for signal intensity in the upper thoracic cord.
Parallel transmit spatial spectral pulse design with specific absorption rate control: demonstration for robust water excitation at 7 Tesla
Authors: Shao Xin , Ma Xiaodong , Guo Hua , Ugurbil Kamil , Wu Xiaoping
Published: August 2024

There has been an increasing interest in designing parallel transmit spatial spectral (pTx SPSP) RF pulses for reducing transmit B1 inhomogeneity while achieving water selective excitation. In this study, we propose a new pTx SPSP pulse design method with explicit SAR control with nearly complete fat suppression. Our results based on human calibration data acquired at 7T suggest that our method is equally applicable to both kT-point and SPINS pulse design, outperforming an existing method based on combining pTx with binomial pulse design approach. We believe our method will have a utility for high-resolution, whole-brain functional MRI at ultrahigh field.
Reorganization of functional networks in squirrel monkey brain after thalamic injury and their relations to task-specific behaviors
Authors: Sengupta Anirban , Duque Daniela Hernandez , Mishra Arabinda , Reed Jamie , Yang Pai-Feng , Wang Feng , Yang Zhangyan , Chen Li Min , Gore John
Published: August 2024

Resting state fMRI was used to assess whole brain functional networks before and after a targeted, unilateral lesion in the hand and arm representation of the ventroposterior lateral nucleus of the thalamus of squirrel monkeys. Using Independent Component Analysis, the overall whole brain resting state functional connectivity (rsFC) dropped after injury but slowly recovered. The trajectory of network changes corresponded well with quantitative metrics of animal performance on a behavioral task using the affected hand. Some functional networks showed reductions in connectivity post injury followed by recoveries while others reflected compensatory increases that began in the first week after injury.
Biphasic fMRI responses to optogenetic stimulation of parvalbumin interneurons
Authors: Vo Tan Thanh , Im Geun Ho , Drew Patrick , Kim Seong-Gi
Published: August 2024

Parvalbumin (PV) neurons are the largest population of cortical interneurons, thus their role in neurovascular coupling is highly important in interpreting fMRI data, especially optogenetic fMRI. However, PV-based hemodynamic response is not well-understood. Here, we observed the biphasic BOLD response with initial vasoconstriction and follow-up ultraslow vasodilation at the stimulation site by PV photostimulation, while negative BOLD was observed at the downstream output. CBV-fMRI revealed that vasoconstriction localizes at middle to deeper layers matching with the distribution of glutamatergic neurons, while vasodilation propagated from superficial layers driven by neuropeptide substance P signaling.
Functional connectivity changes of brainstem nuclei in prodromal Parkinson’s disease: A 7 Tesla resting-state study
Authors: Singh Kavita , Gomar Maria Guadalupe , Stefani Ambra , Videnovic Aleks , Bianciardi Marta
Published: August 2024

Based on animal and human lesion studies, isolated rapid-eye-movement (REM) sleep behavior disorder (iRBD) is due to changes in arousal/motor brainstem nuclei structure and function and is recognized as the hallmark of Parkinson disease (PD). Resting-state fMRI studies in iRBD in humans mostly studied changes in nigrostriatal/nigrocortical connectivity pathway but failed to assess the brainstem circuits involved. To fill this gap, we investigated the functional connectivity of 20 brainstem nuclei relevant for iRBD using high-sensitivity and high spatial-resolution 7 Tesla resting-state fMRI, as well as a recently developed in-vivo probabilistic atlas of brainstem nuclei.
The Brainstem Navigator: a toolkit to investigate brainstem nuclei structure, function, and connectivity in living humans
Authors: Bianciardi Marta , Cauzzo Simone , Toschi Nicola , Koley Subhranil , García-Gomar Maria , Singh Kavita
Published: August 2024

Brainstem nuclei are deep gray matter regions involved in vital functions such as arousal/sleep/motor/sensory/autonomic/nociceptive/limbic/sensory function. Due to their small size and limited MRI contrast, these nuclei are difficult to visualize in conventional imaging of living humans. We generated and released the Brainstem Navigator toolkit, which enables the automatic identification of brainstem nuclei location in conventional and advanced MRI of living humans. It includes in-vivo probabilistic atlas labels for 31 brainstem nuclei generated by multi-contrast 7 Tesla MRI. We also developed coregistration routines optimized for the brainstem in 3 Tesla and 7 Tesla MRI data in health and disease.
Exploring neuroimaging biomarkers and their correlations to neurocognitive function in adult childhood cancer survivors
Authors: Ljungberg Maria , Jalnefjord Oscar , Rydén Isabelle , Fernström Erik , Andersson Linnea , Schneiderman Justin , Blomstrand Malin , Kalm Marie , Björkman-Burtscher Isabella , Jarfelt Marianne
Published: August 2024

Cranial radiotherapy (CRT) is effective; however, survivors of childhood cancer often suffer from cognitive deficits. Two adult patient groups that received different CRT exposures as children were included, as well as healthy volunteers. The MR-examination comprised of anatomical imaging, DTI and MR spectroscopy of the hippocampus. Differences were found between the group that received highest CRT dose and the control group in hippocampal volume, tNAA/tCr-ratio of hippocampus and several DTI-measures in e.g., corpus callosum. Correlations was found between DTI-measures (MD/RD/AD) in some of the studied white matter tracts and several of the used neuropsychological tests, e.g., BVMT-R Sum and Coding.
In-Vivo T2 measurements of fetal brain in 1.5T
Authors: Bhattacharya Suryava , Price Anthony , Uus Alena , Sousa Helena , Marenzana Massimo , Colford Kathleen , Murkin Peter , Lee Maggie , Cordero-Grande Lucilio , Teixeira Rui , Malik Shaihan , Deprez Maria
Published: August 2024

Fetal brains go through rapid development, resulting in significant changes in tissue observable by MRI, during gestation. This work presents a quantitative MR imaging pipeline that aims to measure T2 relaxation in fetal brains from clinically acquired single-shot TSE sequences, reconstructed using slice to volume registration (SVR). Images with different echo times (TE) were acquired using a 1.5T MR system; we explored both a simple exponential decay model and more complex simulation-based dictionary for T2 estimation. Measured T2 values are greater than estimates from neonates and developmentally important regions such as the subplate are visible with significantly longer T2s.
An investigation of the glial biomarker myo-Inositol as a marker of brain inflammation in elderly patients with and without delirium.
Authors: Howe Franklyn , Richardson Daniel , Binnie Lauren , Khan Uzma , Rich Philip , Davis Daniel , Hainsworth Atticus , Isaacs Jeremy
Published: August 2024

Myo-Inositol is sometimes considered a marker of brain inflammation and studies indicate mI (mI/tCr) increases with age up to the 6th decade. We performed 1H MRS in four brain regions of very elderly hospitalised patients (n=25, aged 67-90 yrs) of which 12 had delirium. Elevated mI/tCr was associated with increasing Fazekas score for white matter damage (p<0.001) in all regions. In addition mI/tCr and mI/NAA showed negative correlation with age (p<0.001). There were no significant differences between patients with or without delirium. Decreased mI/tCr due to reduced glial cell numbers or dysfunction may coincide with increased mI/tCr associated with inflammation.
Short-term changes in brain structure, perfusion and oxygen metabolism in young adults infected with Omicron: A case control study using MRI
Authors: Shen Rui , Liu Jiachen , Zhao Chenyang , Xu Ning , Yu Shuwan , Qiao Huiyu , Ning Zihan , Han Hualu , Lin Zixuan , Lu Hanzhang , Ding Haiyan , Zhao Xihai
Published: August 2024

We investigated the short-term changes in brain structure, perfusion and oxygen metabolism in young adult patients infected with SARS-COV-2 Omicron but with mild symptoms in China using multimodal MRI. The clinical and brain MR imaging characteristics were compared between patient group (n=98) and healthy control group(n=50). Our findings suggest that there are no significant short-term changes in brain structure, perfusion and oxygen metabolism determined by multimodal MR imaging in young adult patients infected with SARS-CoV-2 Omicron. The potential trend of decline in the volume of cerebral nucleus in the patient group needs further investigation.
Optimizing Deep Brain Grey Matter T1w Imaging at 0.5T
Authors: Curtis Andrew , Chavez Sofia , Stainsby Jeff
Published: August 2024

We report on protocol optimizations to produce white matter nulled images as well as to optimize visualization of subcortical structures. Quantitative T1 mapping of brain tissue at 0.5T estimated the T1 of white and grey matter as 510 and 760 ms respectively. From this an MPRAGE protocol with optimal subcortical matter contrast was found with TI=415ms. Deep brain grey/white matter visualization can be improved with a white matter nulled protocol using TI=250ms.
Cardiac structure discontinuities revealed by ex-vivo microstructural characterization on the Basal Inferoseptal Left Ventricle region.
Authors: CABANIS Pierre , MAGAT Julie , RODRIGUEZ-PADILLA Jairo , RAMLUGUN Girish , YON Maxime , BIHANPOUDEC Yann , PALLARES-LUPON Nestor , VAILLANT Fanny , PASDOIS Philippe , JAIS Pierre , DOS-SANTOS Pierre , CONSTANTIN Marion , BENOIST David , POURTAU Line , DUBES Virginie , ROGIER Julien , LABROUSSE Louis , HAISSAGUERRE Michel , BERNUS Olivier , QUESSON Bruno , WALTON Richard , DUCHATEAU Josselin , VIGMOND Edward , OZENNE Valéry
Published: August 2024

The knowledge of the cardiac microstructure and the 3D myofiber architecture grow years after years with the multiplication and the upgrade of imaging technologies. However, the course of events of pathophysiological processes like cardiac remodeling, and the link with clinical phenotypes are not yet clearly understood. Some concerns have been raised regarding the interpretation of the late gadolinium enhancement (LGE) at the right ventricle attachment or insertion point (RVIP) however 3D microstructure organization of the RVIP has not been extensively described in the literature.
J-difference Editing of Lactate and Threonine in the Human Brain at 3T
Authors: Robison Ryan , Haynes Justin , Ganji Sandeep , Pham Wellington , Smith Seth , Morgan Victoria , Thompson Reid , Omary Reed , Gore John , Choi Changho
Published: August 2024

Lactate is important as a source of energy and a product of metabolism, so the capability to measure lactate accurately and noninvasively by MRS is of high value. We report a new lactate editing approach that enables detection of the lactate 1.3 ppm resonance with minimal contaminations from threonine and other compounds. Narrow-band editing 180° RF pulses were implemented in 1H MR MEGA-PRESS and the sequence was optimized with numerical and phantom analyses. With data from six healthy adult subjects, the lactate and threonine concentrations in healthy brain were estimated to be 0.5±0.1 and 1.0±0.1 mM, respectively.
Respiratory controlled ECG-free cine construction from real-time cardiac magnetic resonance images acquired during free-breathing exercise
Authors: Åkesson Julius , Steding-Ehrenborg Katarina , Töger Johannes , Östenson Björn , Sjöberg Pia , Heiberg Einar
Published: August 2024

This study aimed to enable ECG-free construction of respiratory controlled 3D cardiac magnetic resonance cine series from short-axis 2D real-time images through automated detection of cardiac phases. This is important for imaging during exercise, since obtaining a reliable ECG-signal can be difficult. Visually coherent cines could be constructed for midventricular slice positions through detecting cardiac phases from automated left ventricular segmentations in real-time timeframes, but not for apical and basal slice positions. Deep learning-based regression of cardiac phases directly from images was investigated to handle this problem, but apical and basal cine construction remains an open problem.
Effects of myelin structures on R2 values in the aged rat corpus callosum
Authors: Cho Hwapyeong , Cho Hyung Joon
Published: August 2024

In this study, the effects of myelin structures such as myelin volume fraction (MVF) and myelin sheath thickness (MST) were investigated by measuring the intra/extracellular water signals in post-mortem aging rat brains. R2 values calculated by intra/extracellular water signals obtained using Carr-Purcell-Meiboom-Gill (CPMG) sequence are theoretically verified by comparison with transmission electron microscopy (TEM) and simulation results. It was confirmed that MVF affects the increase of R2 and MST affects the decrease of R2, and the analysis of R2 through this relationship was statistically significant. These results suggest that effects of myelin structures may affect CPMG-based intra/extracellular water signals.
Conditional Denoising Diffusion Probabilistic Models for Inverse MR Image Recovery
Authors: Yurt Mahmut , Ozturkler Batu , Setsompop Kawin , Vasanawala Shreyas , Pauly John , Chaudhari Akshay
Published: August 2024

High-resolution, multi-contrast magnetic resonance imaging (MRI) protocols are required for accurate clinical diagnoses, but are limited by long scan times. Recovering high-quality, multi-contrast images from low-quality accelerated acquisitions is a promising approach to mitigate this limitation. Prior studies have demonstrated deep-learning for tasks such as contrast synthesis, image super-resolution, and image reconstruction. However, each of these tasks requires different architectures and training paradigms. Motivated by these challenges, we introduce a unified conditional denoising diffusion probabilistic model (DDPM) for inverse MR image recovery. Experiments performed on three image recovery tasks demonstrate that DDPMs achieve superior performance compared to prior state-of-the-art approaches.
Single-shot T2-FLAIR mapping via inversion recovery multiple overlapping-echo acquisition and deep neural network reconstruction
Authors: Lin Yanhong , Yang Qinqin , Geng Wenhua , Huang Haitao , Bao Jianfeng , Cai Shuhui , Chen Zhong , Cai Congbo
Published: August 2024

T2-weighted imaging via conventional FLAIR sequence can suppress the signal of cerebrospinal fluid (CSF), making it easier for identifying long T2 lesions in the vicinity of the CSF. But it was usually used for qualitative analysis because of its inevitable time-consuming acquisition. In this study, we applied inversion recovery overlapping-echo acquisition together with deep learning-based reconstruction to achieve ultra-fast T2-FLAIR mapping. In vivo results from a healthy volunteer and two glioma patients demonstrate the good accuracy and robustness of our proposed method.
Thalamic nuclei changes in early vs. late onset Alzheimer’s Disease
Authors: Forno Gonzalo , Hornberger Michael , Lladó Albert , Saranathan Manojkumar
Published: August 2024

Age at symptom onset distinctly affects thalamic nuclei alongside AD. While Early Onset AD showed significant anteroventral (AV) nucleus changes associated with increasing tau pathology, Late onset AD AV nucleus was associated with Aβ42 levels but no significant volume changes were found.
Improved Low-Rank and Subspace Reconstruction for Magnetic Resonance Fingerprinting with Self-Navigating Acquisitions
Authors: Lu Hengfa , Ye Huihui , Zhao Bo
Published: August 2024

Low-rank and subspace reconstruction methods have achieved state-of-the-art performance for MR Fingerprinting with highly-undersampled data. The existing methods learn the temporal subspace from an ensemble of magnetization evolutions generated from Bloch simulations. In this work, we present a novel self-navigating acquisition scheme for MR Fingerprinting, which utilizes a dual-echo acquisition strategy to enable subspace estimation from physically-acquired training data. The proposed acquisition substantially improves the accuracy of the low-rank and subspace reconstruction, especially when the acquisition length is short. We demonstrate the performance of the proposed method with phantom experiments and in vivo experiments.
Mapping Placenta Structure and Function with Low-Field MRI
Authors: Slator Paddy , Hutter Jana , Tricot Raphael , Verdera Jordina , Hajnal Joseph , Alexander Daniel
Published: August 2024

Placental MRI is emerging as a promising adjunct to ultrasound during pregnancy. Low field MRI is appealing for multiple reasons and can support the widespread roll out of placental MRI. Here we provide a proof-of-concept that a quantitative placental imaging technique that has been demonstrated at high-field (1.5T / 3T) – combined T2*-diffusion MRI – is also viable at low field (0.55T). We highlight similarities and differences in low-field maps compared to the current state-of-the-art high-field maps and highlight key areas for future work to realise the potential of low-field placental quantitative MRI during pregnancy.
Assessing within-subject rates of change of placental magnetic resonance imaging diffusion metrics
Authors: Cromb Daniel , Slator Paddy , Price Anthony , De La Fuente Miguel , Egloff-Collado Alexia , Rutherford Mary , Counsell Serena , Hutter Jana
Published: August 2024

This study provides unique data on the evolution of quantitative multi-modal placenta MRl measures over gestation, including, crucially, within-subject results. A multi-compartmental T2*-IVIM model was employed, suited to the complex physiology of the human placenta, and matched to the deployed multi-parametric acquisition technique.
The effects of maternal flow on placental DWI data
Authors: Hutchinson George , Blakey Adam , Dellschaft Neele , Jones Nia , O'Dea Reuben , Leach Lopa , Hubbard Matthew , Houston Paul , Gowland Penny
Published: August 2024

Placental diffusion imaging data is assumed to be driven by a combination of slow diffusive processes, as well as faster incoherent terms. How these faster incoherent terms combine within a voxel is not obvious, and here we investigate this further by comparing a mathematical simulation of maternal flow through a single placentone to data collected in utero. We observe maternal flows can cause IVIM like effects, with slow exponential decays, but also regions of fast IVIM similar to those observed in the placenta, as well as 'rebounding' of signal.
Association between brain metabolites and head impact exposure measured with MRS in a cohort of high school American football athletes
Authors: Liu Zexuan , Dudley Jonathan , Ahmed Nadine , Diekfuss Jed , Edmondson David , Cecil Kim , Yuan Weihong , Zuleger Taylor , Slutsky-Ganesh Alexis , Foss Kim Barber , Myer Gregory , Fleischer Candace
Published: August 2024

Diagnosis and prognosis of sports-related concussion is challenging. In this prospective controlled clinical trial of 215 high school American football athletes, we evaluated relationships between brain metabolite and head impacts as a function of concussion diagnosis and wearing a jugular vein compression (JVC) collar. Changes in total choline between pre- and post-season, measured with MR spectroscopy, were positively correlated with mean g-force thresholds above 80g in athletes diagnosed with a concussion, suggesting choline may be a key metric of injury. Metabolite alterations were minimally affected by the JVC collar and only at mean g-force thresholds of 100, 110 and 120g.
Cardiac CEST MRI under the influence of very short saturation pulses – an analysis approach
Authors: Schache Daniel , Peddi Ajay , Nahardani Ali , Faber Cornelius , Hoerr Verena
Published: August 2024

Cardiac CEST MRI in mice rely on the application of very short saturation pulses. These pulses cause disturbing signal modulation in the CEST spectrum preventing a consistent data analysis. To correct for this, an additional approach named DOSE was established in the data analysis pipeline. The DOSE-corrected analysis was validated in vitro on a glucose concentration series as well as in vivo on cardiac glucoCEST experiments of nine healthy mice. Hereby, oscillations in the CEST spectra could be reduced substantially ensuring a consistent quantification.
Multiscale Entropy Analysis of Resting State fMRI in Pre-Adolescents with ADHD
Authors: Zhang Ru , Jann Kay , Wang Danny , Duval Christina , Murray Stuart
Published: August 2024

The current study used resting state functional magnetic resonance imaging to measure the complexity of pre-adolescents with ADHD but no other comorbidities. We ran a factorial 2 (Group: ADHD, Control) by 2 (Sex: Male, Female) analyses of covariance on the multiscale entropy (MSE) maps with the pubertal development status as a covariate. It revealed MSE values were significantly lower in the ADHD group than the control group in various regions, including bilateral superior frontal gyrus, bilateral precuneus, right inferior/middle frontal gyrus/postcentral gyrus/insular, and left precentral gyrus/middle cingulate gyrus (t = -3.131 to -2.445, p < 0.015).
Direct estimation of metabolite maps from undersampled k-space data using linear tangent space alignment
Authors: Ma Chao , Marin Thibault , Han Paul , El Fakhri Georges
Published: August 2024

Conventional MRSI methods perform MRSI image reconstruction and spectral quantification in two separate steps. This work presents a novel direct estimation method for MRSI that reconstructs high-resolution metabolite concentration maps from undersampled k-space data, leveraging a linear tangent space alignment (LTSA) model for spectral quantification and a low-rank (LR) model for denoising. Furthermore, the proposed framework allows estimating the temporal basis functions of the LR model from the undersampled, noise-corrupted k-space data, thus eliminating the need for experiment-dependent or pre-acquired spectral training data. The performance of the proposed method was validated using numerical simulation phantom and in vivo MRSI data.
Mapping human gastric motility using contrast-enhanced MRI with a natural test meal
Authors: Wang Xiaokai , Cao Jiayue , Han Kuan , Choi Minkyu , Bazan Ana Saavedra , Nielsen Jon-Fredrik , Noll Douglas , Liu Zhongming
Published: August 2024

MRI with oral contrast agents has been increasingly used to image the gastrointestinal tract in animals and humans. However, it has not been established for broad clinical applications. This study describes a set of natural ingredients abundant in manganese ions to enable rapid and contrast-enhanced MRI of the human gastrointestinal tract. A pipeline of advanced analyses reveals the structure of the stomach, dynamic transit of the food inside the stomach, and muscle activity of the stomach wall. Results offer quantitative biomarkers and mechanistic insights for gastric emptying, accommodation, and motility in humans, and merit future studies of gastrointestinal functional disorders.
Correlations between adipose tissue volume changes and its baseline MR-characteristics in people with obesity undergoing a caloric restriction
Authors: Junker Daniela , Wu Mingming , Rupp Selina , Han Jessie , Näbauer Stella , Reik Anna , Wiechert Meike , Somasundaram Arun , Makowski Marcus , Hauner Hans , Holzapfel Christina , Karampinos Dimitrios
Published: August 2024

Results of weight loss interventions differ individually. MRI-based quantification and characterization of adipose tissue (AT) offers methods to identify possible AT-phenotypes that facilitate AT loss. The purpose of this analysis was to evaluate how, in people with obesity undergoing an 8-week formula-based weight loss intervention, the relative AT and lipid volume loss of the subcutaneous and visceral AT depot correlate to the proton density fat fraction (PDFF) and the total volume of AT as well as the volume of lipids in each depot at the beginning of the diet.
SNR-efficient, motion-robust multi-echo SPGR with k-space aliasing
Authors: Lally Peter , Chiew Mark , Matthews Paul , Miller Karla , Bangerter Neal
Published: August 2024

The behaviour of magnetisation under RF spoiling is typically considered to be pseudorandom from TR to TR. Here we describe a model for the coherent underlying phase behaviour which we exploit in a new acquisition strategy. We propose this as an SNR-efficient and motion-robust alternative to multi-echo spoiled gradient echo acquisitions.
MR Sampling Patterns Learned with Variational Information Maximization
Authors: Alkan Cagan , Vasanawala Shreyas , Pauly John
Published: August 2024

Variational information maximization allows joint optimization of MR data sampling and reconstruction and improves reconstruction quality upon the heuristically designed sampling patterns. Here, we analyze the learned sampling patterns with respect to changes in acceleration factor, measurement noise, anatomy, and coil sensitivities in order to provide some interpretation. We show that all of these factors contribute to the optimization result by impacting the sampling density, k-space coverage and point spread functions of the learned sampling patterns.
Cartesian Ultrashort Echo Time (CUTE) Imaging of the Lung Parenchyma
Authors: Thompson Richard , Keen Christopher , Jones Hefin , Coulden Richard , Seres Peter , Grenier Justin
Published: August 2024

The Cartesian UTE (CUTE) sequence provides high quality three-dimensional imaging of the lung parenchyma (TE = 140 us) without the requirement for k-space gridding in a short breath-hold. Phantom validation and comparison to an existing UTE sequence (Spiral VIBE) is provided in 64 healthy subjects and in clinical examples.
AMU7T: a 3D qT1 and T2*w high-resolution in vivo template with refined white and gray matter parcellation dedicated to 7T spinal cord MR analyses
Authors: Le Troter Arnaud , Laines Medina Nilser J. , Mchinda Samira , Cohen-Adad Julien , Callot Virginie
Published: August 2024

Ultra-High-Field MRI has opened new perspectives for spinal cord exploration due to improved spatial resolution and contrast. The present work proposes a dedicated 7T multimodal 3D qT1 and T2*w template and a parcellation including eight substructures within gray matter, thirty WM tracts and three inter-hemispheric ROIs, for an accurate atlas-based segmentation in the subject space. This atlas was interpolated in the 3D PAM50 space to benefit from the advanced functions for registration implemented in the SCT. A preliminary segmentation result in healthy subject gives promising perspectives for group studies.
MRI detects macro- and microstructural changes to normal brain tissue following hemi-brain radiotherapy
Authors: Dickie Ben , Forster Duncan , Bryce-Atkinson Abigail , Lövgren Izabelle , Abravan Azadeh , van Herk Marcel , Williams Kaye
Published: August 2024

Approximately 50-90% of patients that survive treatment for brain tumours experience dementia-like cognitive impairments. Here we use MRI and behavioural testing to assess longitudinal changes to brain macro- and microstructure and cognitive dysfunction following hemi-brain radiotherapy. We show shrinkage of cortical and hippocampal regions in the irradiated hemisphere, and expansion of cortical tissue in the non-irradiated hemisphere relative to non-irradiated control mice. Brain microstructure was also changed including increases in gray matter diffusivity, and decreases in white matter fractional anisotropy. Changes on MRI were accompanied by early and persistent deficits in novel object recognition.
MR thermometry of RF heating in the human brain at 7T using the harmonical initialized multi-echo model with SVD-based motion correction
Authors: Kikken Mathijs , Steensma Bart , van den Berg Cornelis , Raaijmakers Alexander
Published: August 2024

A multi-echo signal model was presented to measure RF-induced temperature rise in the brain at 7T. The proposed method corrects drift fields based on near-harmonic 2D reconstruction and is complemented by an SVD-based motion-correction scheme. The method was tested in 2 volunteers, showing a maximum temperature increase of 0.25 °C with a precision of 0.12 °C. The reliability of the results was strengthened by measurements in which a heating pad was placed on the forehead of one volunteer. This measurement and thermal simulations indicated that the heatpad induced considerably more heating in the brain (3.5 °C) than SAR-constrained RF exposure.
Simultaneous BOLD fMRI and two-photon microscopic imaging on mice brain at 16.4T
Authors: Zhang Guangle , Zhu Wei , Cheng Zongyue , Wang Chenmao , Ugurbil Kamil , Zhu Xiao-Hong , Cui Meng , Chen Wei
Published: August 2024

While BOLD-based fMRI can non-invasively map whole brain activation and connectivity in humans and animals, the BOLD signal provides only an indirect measure of neural activity, and its cellular and neurophysiological origins remain not fully understood. We have developed a multi-scale neuroimaging modality allowing simultaneous fMRI and two-photon microscopic imaging (TPMI) on mice brains at UHF (16.4T). With the virus injection of GCaMP6s into the mouse brain, for the first time, we have successfully obtained functional MR images of the mouse brain and the neuronal calcium signals at layer II-III of the right S1 cortex simultaneously at resting state.
MRI-based porosity index and suppression ratio in the tibial cortex: significant differences in normal, osteopenic, and osteoporotic subjects
Authors: Jerban Saeed , Ma Yajun , Moazamian Dina , Athertya Jiyo , Dwek Sophia , Jang Hyungseok , Woods Gina , Chung Christine , Chang Eric , Du Jiang
Published: August 2024

The porosity index (PI) and the suppression ratio (SR) are two rapid MRI-based techniques developed using ultrashort echo time (UTE) sequences to evaluate the cortical bone microstructure. We have investigated the performance of PI and SR in detecting tibial bone quality differences between osteoporosis (OPo) patients, osteopenia (OPe) patients, and healthy volunteers with normal bone (Normal). We also investigated the correlations of PI and SR with DEXA T-score performed at the hip in patients. PI and SR were significantly higher in the OPo group compared with the Normal and OPe groups. DEXA T-score was significantly correlated with PI and SR.
Widening access and increasing value to fetal MRI with a clinical 20min low-field 0.55T fetal exam in 40 participants
Authors: Verdera Jordina Aviles , Story Lisa , Hall Megan , Finck Tom , Egloff Alexia , Malik Shaihan , Rutherford Mary , Hajnal Joseph , Tomi-Tricot Raphael , Hutter Jana
Published: August 2024

Comprehensive anatomical and functional fetal examination at low field (0.55T) MRI, obtained using a 20min protocol in 40 pregnant women demonstrates high quality data suitable for quantitative analysis both for anatomical radiological values and for functional T2* and diffusion values, all in-line with previously reported higher field values. It opens novel avenues and widens access to fetal MRI to new groups such as the fast growing fraction of obese and overweight pregnant women, in whom comprehensive assessment by screening ultrasound may be difficult.
Highly accelerated FLEXA 3DTOF MR Angiography with iterative deep learning reconstruction
Authors: Takei Naoyuki , Brada Rafi , Ahn Sangtae , McKinnon Graeme , Zhu Xucheng , Nozaki Atsushi , Okuda Shigeo , Jinzaki Masahiro , Wakayama Tetsuya
Published: August 2024

Rapid non-contrast MRA of supra-aortic arteries is necessary to select proper patient for endovascular therapy (EVT) as EVT has become the predominant therapy of acute ischemic stroke. However, conventional 3DTOF has long scan time of 6-7 minutes to cover the entire carotid artery. A highly accelerated MRA with iterative deep learning reconstruction was developed to provide the wide scan coverage and less motion sensitivity within 1 minute. We evaluated the technique with prospectively and retrospectively undersampled data demonstrating high-quality vessel visualization and improved acquisition efficiency at 8x acceleration.
Real-time Needle Tracking Under 0.55T MRI Using Current Controlled B1 Field Artifacts
Authors: Uzun Dogangun , Yildirim Dursun Korel , Ramasawmy Rajiv , Potersnak Amanda , Campbell-Washburn Adrienne , Kocaturk Ozgur , Lederman Robert
Published: August 2024

In this work, an interventional device tracking method under high performance 0.55T MRI is presented using a custom designed nitinol needle. Ultra-thin miniature solenoid coil markers were designed and printed on the needle using conductive ink. A negative contrast is created around the needle by applying an alternative current to the markers and hence introducing an offset to the B1 field. A signal generator circuit is designed for supplying and controlling the AC signal and the visibility of the needle is tested under MRI with in-vitro experiments during a real time b-SSFP sequence.
Development of a cost-effective, fiber optic-based, MRI-compatible EEG system: a proof-of-concept study
Authors: Potter Michael , Holz Emily , Demblowski Lindsay , Hunkar Kyle , Anazodo Udunna , Preble Stefan , Asllani Iris
Published: August 2024

A cost-effective, 8-channel, MRI-compatible optical EEG prototype was implemented and tested. The protoype has the potential to be especially suited for low-field MRI applications. The system uses PhotrodeTM technology, a high impedance device that can pick up signals without the need for "wet" contact with the skin. The minimum resolvable voltage of the modulator was ~ 12.5 uV, sufficient for most EEG waves.
Axonal Diameter Mapping using High Performance Gradients: Feasibility study and Repeatability of Estimates
Authors: Abad Nastaren , Ajala Afis , Bhushan Chitresh , Zhu Ante , Marinelli Luca , Fiveland Eric , Lee Seung-Kyun , DeMarco J , Shih Robert , Hood Maureen , Kohls Gail , Morris H. , Kenney Kimbra , Ho Vincent , Foo Thomas
Published: August 2024

High performance gradients allow for the exploration of an expanded diffusion parameter space, that simplifies biophysical model at ultra-high b=7-30 ms/μm2. The choice of b-encoding space can suppress contributions from extra-axonal water signal while utilization of high performance gradient systems allows for maintaining short echo times (TE<63 ms) with adequate SNR. In this study, the feasibility and reproducibility of mapping effective axonal diameter distributions in the in-vivo brain was assessed by making use of a test-retest paradigm. Whole brain white-matter and parcel based reproducibility and sensitivity were evaluated for this promising biomarker.
Characterization of T2-dependent microstructural spectra using combined relaxation-diffusion MRI
Authors: Ning Lipeng , Westin Carl-Fredrik , Rathi Yogesh
Published: August 2024

We proposed a method for joint modeling and analysis for diffusion MRI data with multiple TEs and examined the performance of using in vivo data acquired from a clinical scanner. The contribution of this work includes the characterization of b-value-dependent T2 relaxation rates, comparing prediction results using subsampled TEs, and characterization of microstructural spectral and long and short TEs using extrapolated signals. The results show that the proposed method can provide novel features to characterize T2-dependent microstructure using rdMRI acquired from clinical scanners.
BB MRI for monitoring aneurysm treatment – a novel biomarker?
Authors: Pravdivtseva Mariya , Toraman Hivnu , Korte Jana , Gaidzik Franziska , Berg Philipp , Bautz Lana , Wodarg Fritz , Hövener Jan-Bernd , Jansen Olav , Larsen Naomi
Published: August 2024

Treating life-threatening intracranial aneurysms with flow modulating devices (FMDs) is mostly successfull, but may lead to complications and even delayed aneurysm rupture. A biomarker indicating treatment success is direly needed. Flow MRI can detect flow reduction, but it is impaired by metal artifacts from FMDs. Black-blood (BB) MRI is less sensitive to metal artifacts and often results in poor slow-flow suppression. We hypothesize that BB contrast changes after aneurysm treatment. Here, after placing FMDs in 3D-printed aneurysm models, an enhanced signal was found on BB MRI, associated with the reduced aneurysmal flow after flow modulation and thus possible treatment success.
Super-resolution assessment of relative pressure in intracranial atherosclerosis using ML-enhanced 4D Flow MRI
Authors: Winter Patrick , Marlevi David , Aristova Maria , Ferdian Edward , Schollenberger Jonas , Vali Alireza , Moore Jackson , Markl Michael , Abdallah Ramez , Ansari Sameer , Figuerora C , Nordsletten David , Young Alistair , Schnell Susanne
Published: August 2024

In vivo measurements of intracranial pressure differences using 4D flow are useful to assess health risks associated with intracranial atherosclerotic disease (ICAD). In the clinical routine, approximations of the Navier-Stokes equation are used to derive relative pressure values, which can be inaccurate in intracranial vessels. Recently we presented an algorithm using a virtual work-energy formulation(vWERP). While this technique yields more accurate pressure estimations in intracranial settings, still systematic errors due to insufficient spatial resolution were observed. Here, we apply artificial intelligence-based super resolution for more accurate assessments of pressure values near the stenosis in a cohort of ICAD patients.
Subclassification of Barcelona Clinic Liver Cancer Stage A HCC using fully automatic 3D segmentation-derived total tumor burden at MRI
Authors: Wei Hong , Jiang Hanyu , Chen Yidi , Zheng Tianying , Yang Ting , Zhang Xiaolan , Zheng Chao , Song Bin
Published: August 2024

In the present study of 297 patients, we evaluated the role of three-dimensional (3D) quantitative tumor burden analysis using fully automatic segmentation at magnetic resonance imaging in the subcategorization of the Barcelona Clinic Liver Cancer (BCLC) stage A hepatocellular carcinoma (HCC) after curative resection. Our results demonstrated that 3D quantitative total tumor burden (TTB) and serum a-fetoprotein were independent predictors of overall survival and could be used to subcategorize the BCLC stage A HCC. Additionally, the higher TTB (>18.5%) was correlated to more aggressive tumor behaviors (i.e., microvascular invasion and poor tumor differentiation).
NeuroVerse: Neuroimage Processing Tools Across a Century of Life
Authors: Ahmad Sahar , Chen Xiaoyang , Lyu Wenjiao , Wu Jinjian , Li Yifan , Zou Yicheng , Thung Kim-Han , Liu Siyuan , Yap Pew-Thian
Published: August 2024

The availability of large-scale multi-site neuroimaging data present unprecedented opportunities for revealing the brain's macroscopic and microscopic organization across the lifespan. Existing neurodevelopmental studies lack consensus, owing to variable preprocessing methods that result in inconsistent brain features. Existing neuroimage processing tools typically cater to specific life periods, limiting their applicability to data covering the entire human lifespan. Here, we present robust automatic tools for accurate and consistent processing of neuroimaging data covering a century of life.
Incorporating DCE derived perfusion terms to inform fitting of hyperpolarized pyruvate metabolism in a human thyroid tumor.
Authors: Walker Christopher , He Renjie , Xu Zhan , Michel Keith , Martinez Gary , Harlan Collin , Mohamed Abdallah , Fuller Clifton , Lai Stephen , Bankson James
Published: August 2024

Dynamic contrast enhanced MRI was used to derive perfusion terms which were incorporated into the fitting of hyperpolarized pyruvate to lactate apparent conversion rates. Incorporation of the DCE data reduced the fit metabolic conversion rates across the data set but more so for the post therapy data resulting in a significant decrease in kpl after therapy. These results suggest that more effort is needed to disentangle perfusion from metabolic effects when analyzing HP MRI data.
3D myocardial perfusion quantification using hyperpolarized HP001
Authors: Zhao Yupeng , Olin Rie Beck , Hanson Lars G. , Hansen Esben Søvsø Szocska , Laustsen Christoffer , Ardenkjær-Larsen Jan Henrik
Published: August 2024

We propose a 3D gradient echo sequence with hyperpolarized HP001 as contrast agent for whole heart myocardial perfusion quantification. The estimated perfusion values are correlated with the perfusion values estimated from dynamic contrast enhanced (DCE)-MRI.