bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-Dose Ferumoxytol Infusion Provides Effective Vascular Suppression for Magnetic Resonance Neurography
Authors: Pedrick Emily , Sneag Darryl , Colucci Philip , Duong Mylinh , Vanderbeek Alyssa , Tan Ek
Published: August 2023

This study investigated the effectiveness of a low-dose (25% of a single treatment dose for anemia) ferumoxytol-infusion for vascular suppression in T2-weighted MR neurography of the brachial plexus. 3D STIR-FSE and 2D Dixon-FSE sequences of the brachial plexus were acquired in 12 healthy volunteers pre- and post-ferumoxytol. Quantitative and subjective assessments by two readers demonstrated superior vascular suppression and nerve visualization post-ferumoxytol without negatively affecting soft tissue contrast or fat suppression.
MetaPulse2D: methodology to enable universal slice specific spokes pulses in parallel transmission
Authors: Mauconduit Franck , Gras Vincent , Vignaud Alexandre , Boulant Nicolas
Published: August 2023

When using a slice-by-slice RF shimming or multi-spokes pulses in 2D parallel transmission MRI, the solution is valid for a specific slice position and orientation. Here, we introduce a new pulse concept were the spoke coefficients and gradient blips are smooth functions of the slice position and orientation. We show that this design performs better than CP mode and equivalent to other designs. However, it enables to tilt or reposition slices without requiring additional optimization. This solution promotes signal smoothness through slices. Additionally, it can be pre-computed using the Universal Pulse concept or computed online using a tailored approach.
Functional eigenvector centrality dynamics are related to amyloid deposition in preclinical Alzheimer’s Disease
Authors: Lorenzini Luigi , Silvia Ingala , Collij Lyduine , Tijms Betty , Mutsaerts Henk , Wottschel Viktor , Haller Sven , Blennow Kaj , Frisoni Giovanni , Chételat Gael , Payoux Pierre , Lage-Martinez Pablo , Waldman Adam , Wardlaw Joanna , Ritchie Craig , Gispert Juan Domingo , Visser Pieter Jelle , Scheltens Philip , Frederik Barkhof , Wink Alle Meije
Published: August 2023

Recent evidence suggests that amyloid deposition in the brain follows — and subsequently affects — temporal variability of neuronal activity and functional connectivity. Temporal variability in functional brain network properties connote changes in participation of functional hubs in different subnetworks. We confirm previous findings of alterations of functional eigenvector centrality (EC) in relation to amyloid, and demonstrate that those regions show altered dynamic EC profiles with lower variability over time, hence lower network integration.
Analysis of Hippocampal Subfield Diffusion Imaging for Lateralization in Mesial Temporal Sclerosis
Authors: Kung Gustavo Chau Loo , Chiu Andrew , Davey Zachary , Mouchawar Nicole , Carlson Mackenzie , Martin Douglas , Graber Kevin , Razavi Babak , McNab Jennifer , Zeineh Michael
Published: August 2023

We performed subfield characterization of Mesial Temporal Sclerosis (MTS) using diffusion metrics. Analysis of MRI from 57 temporal lobe epilepsy patients was based on categorization from medical records, initial clinical radiological reads, and diagnostic changes after subfield DTI analyses. We observed differences in mean diffusivity, axial diffusivity and orientation dispersion in the dentate gyrus of patients with MTS. Differences between MTS and control patients were more pronounced in left MTS.  We demonstrate how these methods may aid in the MRI identification of MTS.
Detection of unilateral changes in thalamic volume and microstructure in focal epilepsy using 7T MRI
Authors: Testud Benoit , Haast Roy , Scholly Julia , Dary Hugo , Le Troter Arnaud , Ranjeva Jean-Philippe , Bartolomei Fabrice , Guye Maxime
Published: August 2023

This work evaluated differences in thalamic morphometry and T1 across drug-resistant temporal (TLE) and non-temporal lobe epilepsy (nTLE) patients using 7T MRI. Results show bilateral thalamic atrophy across all patients, with strongest effects observed in TLE patients and ipsilateral pulvinar and mediodorsal nuclei. Moreover, T1 appeared lower, especially in medial, lateral, and posterior nuclei. While T1 was lowest across nTLE patients, an ipsi- vs contralateral effect was uniquely present in TLE patients. Future, joint analyses with other available myelin- and iron sensitive metrics (e.g., tissue susceptibility and diffusivity), connectivity features and clinical features will increase sensitivity to differentiate among patients.
Differentiation of tumor grade for renal cell carcinoma using MR Fingerprinting
Authors: Tirumani Sree , MacAskil Christina , Markley Michael , Pritts Nicole , Durieux Jared , Elliott Robin , Calaway Adam , Ponsky Lee , Griswold Mark , Flask Chris , Chen Yong
Published: August 2023

In this study, we applied kidney MR Fingerprinting in characterization of renal cell carcinoma (RCC) and correlated the quantitative T1 and T2 values with tumor grade. Our results show significantly lower T2 values between the high-grade/unclassified RCC group and the chromophobe/low-grade RCC group (55±19 vs. 90±24 msec; P<0.05), while no significant difference in T1 values was noticed (P>0.05). More importantly, MRF T1 and T2 measurements provide complementary information in characterization of RCC tumor grades with a sensitivity of 89% and a specificity of 98% in differentiation of the two RCC groups, demonstrating the strength of multi-parametric imaging.
DKI Metrics Provide Improved Sensitivity To Conventional DTI in Differentiating Brain Microstructural Changes in HIV Clade-C Infection
Authors: Salan Teddy , Vyas Sameer , Aggarwal Deepika , Singh Paramjeet , Govind Varan
Published: August 2023

HIV clade-C, found in 50% of HIV cases worldwide, has been reported to have lower neurovirulence than clade-B, more common in the global north. Numerous DTI-based studies have investigated HIV-associated microstructural damage in the brain, yet few looked at clade-C in particular. Moreover, some have reported inconsistent DTI results with respect to HIV. In this study, we use DTI and DKI to determine the extent of microstructural brain damage due to HIV clade-C infection. Our results show that a combined use of DTI and DKI can provide a better description of brain tissue damage among HIV clade-C infected individuals.
4D free-breathing variable density stack-of-stars functional MR urography in young children without sedation: A clinical feasibility study
Authors: Spogis Jakob , Katemann Christoph , Zhang Shuo , Tsiflikas Ilias , Esser Michael , Schäfer Jürgen
Published: August 2023

High-quality magnetic resonance urography (MRU) is clinically valuable to provide a comprehensive evaluation of the renal function and urinary tract in children without ionizing radiation. However, respiration-related patient motion remains a major challenge that impairs diagnostic image quality and hampers an accurate quantitative analysis. In this study, we adopt a novel high temporospatial resolution dynamic-contrast-enhanced (DCE) MRI technique based on 3D radial stack-of-stars gradient-echo sequence acquisition in combination with elliptical variable density k-space scheme for morphological and quantitative MRU and demonstrate its motion robustness in small children in free breathing without sedation.
Characterization of cardiac noise in brain quantitative relaxometry MRI data
Authors: Raynaud Quentin , Yerly Jérôme , van Heeswijk Ruud B. , Lutti Antoine
Published: August 2023

Cardiac-related noise reduces the sensitivity of relaxometry data to brain microstructure properties such as iron or myelin concentration. To address this effect, we aim to characterize cardiac pulsation effects in in-vivo data. We combined a Cartesian pseudo-spiral sampling trajectory with compressed sensing image reconstruction using a temporal total variation regularization to obtain 3D multi-echo images at 12 points of the cardiac cycle. We show that 76% of the full k-space is required in each cardiac bin to maintain 90% of voxels above a 60% sensitivity to physiological noise in the reconstructed images.
MR Image Reconstruction via Zero-Shot Learned Generative Adversarial Transformers
Authors: Dar Salman Ul Hassan , Korkmaz Yilmaz , Cukur Tolga
Published: August 2023

Deep neural network models have demonstrated state-of-the-art performance in MR image reconstruction. These models require information regarding imaging operators during training, which limits their generalization. A recent framework is based on zero-shot learned generative models that learn MR image priors during training and couple imaging operator during inference on test acquisitions. Such models are however based on convolutional architectures that suffer from sub-optimal capture of long range dependencies. Here, we propose a novel architecture based on zero-shot learned generative adversarial transformers that enables efficient capture of long range dependencies via cross-attention transformers while removing reliance on imaging operator during training.
Prepolarized MRI of Hard Tissues and Solid-State Matter
Authors: Morata Jose Borreguero , Hernández Jose Manuel González , Lodeiro Eduardo Pallás , Pérez Juan Pablo Rigla , Guisado Jose Miguel Algarín , Esteve Rubén Bosch , Conde Fernando Galve , Ruíz Daniel Grau , Guridi Rubén Pellicer , Alonso Alfonso Ríos , Baviera Jose María Benlloch , Alonso Joseba
Published: August 2023

Prepolarized Magnetic Resonance Imaging is a long established technique conceived to counteract the loss in signal strength inherent to low field MRI systems. When it comes to hard biological tissues and solid state matter, PMRI is severely restricted by their ultra short characteristic relaxation times. Here we demonstrate that hard tissue prepolarization is possible with a 0.26 T scanner designed for dental MRI. These results can be applied to clinical dental imaging, making low field PMRI scanners a possible replacement for hazardous X ray systems.
Gray matter microstructure imaging by b-tensor encoding at high b-values and high spatial resolution
Authors: Vis Geraline , Spotorno Nicola , Lampinen Björn , Szczepankiewicz Filip , Nilsson Markus
Published: August 2023

Studying gray matter microstructure with dMRI is challenging because of partial volume effects and high orientation dispersion. In this work, we propose a novel method that combines spherical b-tensor encoding, strong diffusion weighting and super-resolution reconstruction to perform high-resolution microstructure imaging of gray matter. We map the tissue mean diffusivity and the microscopic anisotropy which, by their design, are unaffected by partial volume effects and intra-voxel orientation dispersion. We demonstrate the approach in human brain in vivo at a resolution of 1.4 mm isotropic.
Oscillating Gradient (OGSE) and Microscopic Anisotropy Diffusion in the in vivo and ex vivo Marmoset Brain
Authors: Santini Tales , Rahman Naila , Shim Alyson , Inoue Wataru , Everling Stefan , Baron Corey
Published: August 2023

We investigated OGSE and μFA diffusion techniques for the first time in the common marmoset (Callithrix jacchus) brain, which revealed comparable values to those found in humans. The same animal was scanned in vivo and after fixation of the brain, allowing comparison of in vivo and ex vivo OGSE and μFA parameters for the first time in marmosets. There were differences in kurtosis, μFA, and μA that may be caused by slight neurite beading and tissue shrinkage during perfusion/fixation, and temperature differences.
Short superficial U-fiber systems and aging: a longitudinal diffusion MRI study
Authors: Schilling Kurt , Archer Derek , Yeh Fang-Cheng , Rheault Francois , Cai Leon , Hohman Timothy , Shafer Andrea , Resnick Susan , Jefferson Angela , Anderson Adam , Kang Hakmook , Landman Bennett
Published: August 2023

Superficial U-fiber systems are understudied using diffusion tractography, despite making up a majority of the white matter connections. Here, we used a large, longitudinal dataset from the Baltimore Longitudinal Study of Aging, in combination with innovations in U-fiber tractography dissection, to study U-fiber systems in an aging population. We characterize microstructural features, and for the first time, macrostructural features of length and volume, and find significant associations with age. Characterizing what changes occur, and where they occur, in U-fiber systems will complement traditional long-range tractography research to better understand the biological mechanisms of normal aging.
3D-MR-Fingerprinting for Rapid Simultaneous T1, T2, and T1ρ Volumetric Mapping of the Human Articular Cartilage at 3T
Authors: Sharafi Azadeh , Zibetti Marcelo V. W. , Chang Gregory , Cloos Martijn , Regatte Ravinder
Published: August 2023

Conventional quantitative cartilage MRI (e.g., T1, T2, and T1ρ) approaches measure one single parameter at a time. Magnetic resonance fingerprinting (MRF) is a flexible, non-invasive measurement technique that simultaneously quantifies multiple MR parameters. In this work, we proposed a 3D-MRF sequence for the simultaneous volumetric acquisition of submillimetric proton density (PD) image and T1, T2, T1ρ, and B1+ maps of the knee cartilage in clinically feasible scan time (~11 minutes).
Three dimensional multi-parameter quantification of inter-vertebral discs using magnetic resonance fingerprinting
Authors: Menon Rajiv , Sharafi Azadeh , Regatte Ravinder
Published: August 2023

Low back pain that have etiologies related to degenerative intervertebral(IVD) disc changes are difficult to diagnose and treat. Quantitative characterization of the lumbar spine IVD can potentially be useful in detecting early changes to the IVD. In this study a 3D-MR fingerprinting technique was employed that is capable of simultaneously quantifying four different parameters in a clinically feasible time. Five healthy subjects underwent lumbar spine 3D-MRF scans. The results demonstrate that 3D-MRF can simultaneously measure and generate T1, T2, T1ρ, and B1+ volumetric maps of lumbar spine in a single scan within clinically feasible scan time of about 10 minutes.
Cycle-Consistent Adversarial Transformers for Unpaired MR Image Translation
Authors: Dalmaz Onat , Yurt Mahmut , Dar Salman , Çukur Tolga
Published: August 2023

Translating acquired sequences to missing ones in multi-contrast MRI protocols can dramatically reduce scan costs. Neural network models devised for this purpose are characteristically trained on paired datasets, which can be difficult to compile. Moreover, these models exclusively rely on convolutional operators with undesirable biases towards feature locality and spatial invariance. Here, we present a cycle-consistent translation model, ResViT, to enable training on unpaired datasets. ResViT combines localization power of convolution operators with contextual sensitivity of transformers. Demonstrations on multi-contrast MRI datasets indicate the superiority of ResViT against state-of-the-art translation models.
An End-to-End Segmentation Pipeline for Dixon Adipose and Muscle by Neural Nets (DAMNN)
Authors: Landheer Karl , Marchini Jonathan , Geraghty Benjamin , Parasoglou Prodromos , Hectors Stefanie , Sepehrband Farshid , Gale Nicholas , Murphy Andrew , Walls Johnathon , Germino Mary
Published: August 2023

An end-to-end pipeline was developed that processes whole-body Dixon MRI data sets from UK Biobank and corrects for overlapping slices, inhomogeneous signal intensities, and fat-water swaps to produce high quality 3D data sets. Segmentation maps for subcutaneous/visceral fat and left/right thigh muscles from these 3D data sets were then produced using neural networks, and muscle and fat volume phenotypes were extracted. The Jaccard index for the validation data sets was 93.3% for the fat segmentation and 96.9% for the muscle segmentation. Excellent correspondence was obtained with the extracted muscle and fat volumes and similar metrics from a commercially available package.
Visualizing Encoding Efficiency of MR Fingerprinting Sequences using Leave-One-Out Perturbation (LOOP)
Authors: Guenthner Christian , Stimm Johanna , Kozerke Sebastian
Published: August 2023

In Magnetic Resonance Fingerprinting, the accuracy of the results is dominated by undersampling artifacts. While in classical relaxometry techniques, the omission of data always leads to a larger error, in fingerprinting, undersampling artifacts can lead to both an increase or a decrease in error. The “temporal encoding efficiency” of fingerprinting can be analyzed based on the change in matching error upon omission of a single time point (leave-one-out). We propose a first-order perturbation of the undersampling error to visualize and identify temporal sequence segments of primary parameter encoding and apply these insights to shorten an exemplary MRF sequence by truncation.
A 320 km Hyperpolarization Journey: performing [U-13C, d7]glucose DNP in Copenhagen and Hyperpolarized 13C-MR in Aarhus
Authors: Capozzi Andrea , Karlsson Magnus , Hansen Esben Søvsø Szocska , Sanchez Juan Diego , Laustsen Christoffer , Lerche Mathilde , Van Der Klink Jacques , Ardenkjær-Larsen Jan Henrik
Published: August 2023

Dissolution DNP polarizers are expensive, technically demanding and require trained personnel. At the same time, hyperpolarized MR tracers have a half-life short enough to need the polarizer to be placed as close as possible to the MRI scanner. Similarly to PET tracers, being able to receive on demand hyperpolarized contrast agents from a centralized facility would solve this major shortcoming and boost the diffusion of hyperpolarized MR on a wider scale. In this work, using UV-induced non-persistent radicals and purpose build hardware, we demonstrate the first “across-cities-dDNP” experiment.
Evaluating hyperpolarized [1-13C]pyruvate uptake for predicting response to stereotactic radiosurgery in brain metastases
Authors: Cappelletto Nicole , Soliman Hany , Lee Casey , Bragagnolo Nadia , Sahgal Arjun , Chen Albert , Endre Ruby , Perks William , Ma Nathan , Detsky Jay , Heyn Chris , Cunningham Charles
Published: August 2023

Brain metastases are increasingly being treated with stereotactic radiosurgery; however, 20-30% of treated tumors recur locally post-treatment. Hyperpolarized [1-13C]pyruvate magnetic resonance imaging (HP 13C MRI) is an emerging metabolic imaging modality that measures key metabolic phenotypes indicative of tumor biology. Here we investigate pre-treatment [1-13C]pyruvate uptake – a potential marker of monocarboxylate transporter 1 expression and tumor vascularity – via HP 13C MR images as a predictor of local recurrence. [1-13C]pyruvate uptake establishes a robust predictive model (AUC = 0.73) and, as a result, can inform treatment decisions should the model predict a non-response to SRS.
Field orientation matters: vertical open-bore scanners significantly reduce RF heating around implanted deep brain stimulation devices
Authors: Vu Jasmine , Bhusal Bhumi , Nguyen Bach , Sanpitak Pia , Nowac Elizabeth , Pilitsis Julie , Rosenow Joshua , Golestanirad Laleh
Published: August 2023

Radiofrequency (RF) heating of tissue around active electronic implants limits MRI accessibility for patients with deep brain stimulation (DBS) devices. Here, we show that RF heating had an 11-fold reduction on average for a DBS device with clinically relevant, patient-derived lead trajectories during MRI in a 1.2 T vertical scanner compared to a 1.5 T horizontal scanner. Electromagnetic simulations showed up to a 14-fold decrease in the maximum of the 0.1g-averaged SAR, which was consistent in leads with various internal wire geometries/electrical lengths, suggesting that our experimental results could potentially generalize to DBS devices from other manufacturers.
RF Heating of Multi-channel icEEG Electrodes
Authors: Lottner Thomas , Reiss Simon , Rieger Stefan , Fischer Johannes , Bielak Lars , Oezen Ali , Schüttler Martin , Bock Michael
Published: August 2023

Active implantable medical devices restore body function in patients with neurological or other disorders, increasing their quality of life. The RF-safety assessment of neural implants is complex due to the increasing use of multi-channel systems. In this study, the heating characteristics of intracranial EEG electrodes with increasing number of channels is investigated. this study shows that, for the given configurations, the RF-induced heating decreases, when the number of channels of the device is increased. Hence, increasing the grids of planar electrodes might be used to decrease the RF induced heating.
Increasing Peripheral Nerve Stimulation Thresholds Using Gradient Array Coils
Authors: Babaloo Reza , Takrimi Manouchehr , Atalar Ergin
Published: August 2023

Recent high-performance gradient coil designs are primarily limited by Peripheral Nerve Stimulation thresholds rather than hardware. Electrical fields induced by gradient switching may stimulate nerves within the human body if they exceed predefined thresholds. Gradient array coils can reduce the maximum electric field by optimizing feeding currents while generating the desired magnetic field profile within a specified region of interest. Another degree of freedom provided by array configuration is the ability to generate a flexible shaped region of interest, which allows for electrical fields manipulation to increase peripheral nerve stimulation thresholds.
Ultra-high field normative quantitative susceptibility mapping (QSM) in children and cortical pathology in drug-resistant focal epilepsy
Authors: Casella Chiara , Vecchiato Katy , Dokumaci Ayse Sila , Bridgen Philippa , Malik Shaihan , Hajnal Joseph , Giles Sharon , Sedlacik Jan , Shmueli Karin , Wilkinson Tom , Tomi-Tricot Raphael , Carmichael David , O'Muircheartaigh Jonathan
Published: August 2023

We developed an analysis pipeline to explore normative QSM values in children and adolescents at 7T, and assessed the feasibility of this approach for detecting tissue-alterations in paediatric drug-resistant epilepsy. Normative values consistent with previous QSM studies were reported for deep brain regions, and normative cortical susceptibility values were described for the first time in children and adolescents at 7T. Finally, sensitivity to susceptibility changes in epileptogenic lesions was demonstrated using the analysis pipeline.
TWo Interleaved Steady-states for T2 And Rf Estimation (TWISTARE) - a fast 3D-GRE phase-based method of T2 and B1 mapping in 7T brain imaging
Authors: Yacobi Dana , Seginer Amir , Schmidt Rita
Published: August 2023

Quantitative T2 mapping is an important tool towards standardization of MRI in clinics and research, whose implementation in 7T MRI will gain SNR and resolution. In this work, we demonstrate a phase-based method with fast 3D spoiled GRE acquisition to estimate T2 and B1 maps in 7T brain imaging. We introduce a new approach employing a dual steady-state with interleaving flip angles - denoted as TWISTARE. This approach is suited to address the RF field inhomogeneity in 7T and can shorten the total scan duration. The new approach was examined using a 3D head-shaped phantom and in human imaging.
AI-based Automated Liver Image Prescription: Evaluation across Patients and Pathologies and Prospective Implementation and Validation
Authors: Geng Ruiqi , Buelo Collin , Sundaresan Mahalakshmi , Starekova Jitka , Panagiotopoulos Nikolaos , Oechtering Thekla , Lawrence Edward , Ignaciuk Marcin , Reeder Scott , Hernando Diego
Published: August 2023

An automated AI-based method for liver image prescription from a localizer was recently proposed. In this work, this AI method was further evaluated in a larger retrospective patient cohort (1,039 patients for training/testing), across pathologies, field strengths, and against radiologists’ inter-reader reproducibility performance. AI-based 3D axial prescription achieved a S/I shift of <2.3 cm compared to manual prescription for 99.5% of test dataset. The AI method performed well across all sub-cohorts and better in 3D axial prescription than radiologists’ inter-reader reproducibility performance. The AI method was successfully implemented on a clinical MR system and showed robust performance across localizer sequences.
The association of Liver Stiffness with Liver tissue T1 and Superior Mesenteric Artery blood flow across disease severity.
Authors: Bradley Christopher , Mcgrath Deirdre , Cox Eleanor , Palaniyappan Naaventhan , Scott Robert , Guha Indra , Aithal Guruprasad , Francis Susan
Published: August 2023

We assess liver stiffness measured using magnetic resonance elastography (MRE) and longitudinal relaxation time T1 in three groups: healthy volunteers, non-alcoholic fatty liver disease patients and compensated cirrhosis patients. MRE liver stiffness was measured using the Quantitative Imaging Biomarker Alliance (QIBA) recommendation. T1 longitudinal relaxation time of the liver was measured using a respiratory triggered inversion recovery fat-suppressed spin-echo echo planar imaging scheme. A positive correlation between Liver tissue T1 and Liver stiffness (R=0.70, p<0.0001) across the 3 groups was observed. Superior mesenteric artery flow also correlates with liver stiffness (R=0.62, p<0.002) suggesting worsening hyperdynamic circulation with progressive fibrosis.
A principled approach to select DCE-MRI derived radiomics features for evaluation in phase I/II trials
Authors: Berks Michael , McHugh Damien , Porta Nuria , Little Ross , Cheung Susan , Jayson Gordon , Parker Geoff , O'Connor James
Published: August 2023

DCE-MRI biomarkers such as change in median Ktrans have a proven role in drug development in phase I/II trials. There is current interest in using approaches such as radiomics to extract additional information relating to spatial heterogeneity from images and one emerging application is to apply these analyses to clinical trial data where imaging is used to monitor pharmacodynamic change in the tumour microenvironment. Here, we explore the properties of radiomics features extracted from maps of Ktrans and aim to identify features that are repeatable at baseline, show consistent treatment effect and provide additional, independent information to the median Ktrans.
3D Deuterium Metabolic Imaging of the Human Liver at 7T using Low-rank and Subspace Modeling
Authors: Nam Kyung Min , Gursan Ayhan , Lee Nam , Wijnen Jannie , Klomp Dennis , Prompers Jeanine , Bhogal Alex , Hendriks Arjan
Published: August 2023

Deuterium metabolic imaging (DMI) is an emerging technique to spatially map metabolism in vivo through the intake of deuterium (i.e., 2H or D) labeled substrates such as [6,6′-2H2]-glucose. Although DMI has the potential to become a powerful tool to assess liver metabolism, it has limitations due to its long scan time, and low signal-to-noise ratio (SNR) for high spatial resolution in the human body. In this work, we demonstrated the feasibility of low-rank and subspace modeling (LRSM) reconstruction to increase SNR by reducing spectral noise, allowing high spatiotemporal resolution for 3D DMI of the human liver at 7T.
The MotoNet: An MRI-Compatible EEG Net with Embedded Motion Sensors
Authors: van der Kouwe Andre , Jeong Hongbae , Yang Zinong , Straney Donald , Frost Robert , Lewis Laura , Bonmassar Giorgio
Published: August 2023

We introduce a new EEG net, which will allow clinicians to monitor EEG while tracking head motion for correction. Motion during MRI limits patient scans, especially of children and patients with seizures. The MotoNet was built using PTF, embedding EEG/motion sensor pairs on opposite sides in one circuit. MRI safety studies at 3T confirmed maximum heating below 1ºC. EEG/motion measurements were made with a standard commercial EEG system. Using a custom MRI sequence with spatial localization gradients only, we showed that the signal on each channel was highly correlated with motion, allowing for electrode positioning and motion tracking.
A dedicated MRI/PET system for radiotherapy treatment simulation: pathophysiological guidance for small moving target volumes
Authors: Beijst Casper , Branderhorst Woutjan , Lagendijk Jan , Weissler Bjoern , Schug David , Mueller Florian , Radermacher Harald , Borgo Martino , Schuth Wout , Mollink Jurgen , Borst Govaert , Verheyen Marc , van Duin Frank , Klomp Dennis , de Jong Hugo , Schulz Volkmar
Published: August 2023

The Unity 1.5T MR-linac has clinically been introduced to provide stereotactic precision for moving targets. We are now developing an integrated 1.5T MRI/PET system with identical MRI performance for planning of MR-linac treatments. The system offers 70 cm bore size and includes PET detectors mounted in the gap of a split gradient coil. Recently, the first ring of PET detectors was installed. We performed extensive interference tests and acquired the first simultaneous images using a brain phantom. Our vision is that the combination of MR-linac with MRI/PET will allow the use of PET information for stereotactic radiation therapy guidance.
Gradient Waveform Prediction Using Deep Neural Network
Authors: Liu Qi , Nguyen Hoang (Mark) , Zhu Xucheng , Zhai Xiaohui , Li Bo , Xu Jian , Zhang Weiguo
Published: August 2023

A versatile, practical, and effective gradient trajectory correction technique that considers gradient system nonlinearity is proposed using deep learning. Its performance was validated on phantoms and human subjects and demonstrated superior quality than the conventional techniques.
Continuous Arterial Spin Labeling with On-Coil Amplification at 7T
Authors: Saïb Gaël , Huang Sherry , Long Emily , Talagala S. Lalith , Merkle Hellmut , Koretsky Alan P. , Gudino Natalia
Published: August 2023

Continuous arterial spin labeling using a separate neck labeling coil is an attractive approach for imaging perfusion at 7T. This approach is hindered by specialize hardware including a labeling coil and a separate amplifier located outside the magnet room. On-coil amplifiers have demonstrated higher RF power efficiency with minimal cable loss and patient-coil interaction. This work shows that a separate labeling coil using on-coil amplification can be used for flow driven adiabatic inversion in a flow phantom suggesting that it may provide a suitable approach to simplify the hardware package required as well as to improve CASL studies at 7T.
Susceptibility-weighted imaging and quantitative susceptibility mapping of the human brain at 10.5 Tesla: an initial experience
Authors: Wu Xiaoping , Grant Andrea , Ma Xiaodong , Auerbach Edward , Ladder Jerahmie , Sadeghi-Tarakameh Alireza , Eryaman Yigitcan , Lagore Russell , Tavaf Nader , Van de Moortele Pierre‐Francois , Adriany Gregor , Ugurbil Kamil
Published: August 2023

Susceptibility-weighted imaging (SWI) and quantitative susceptibility mapping (QSM) have been shown to provide unique contrasts that can be used to study pathophysiologic changes of tissue magnetic susceptibility in various brain diseases. As magnetic susceptibility effects increase with the main field strength, there has been a rapidly growing interest in performing SWI and QSM at ultrahigh field (UHF) (7 Tesla and above). The aim of this study was to demonstrate how the use of the UHF of 10.5 Tesla may promote SWI and QSM of the human brain.
Myelin Water Imaging Using a New 3D Short TR Adiabatic Inversion Recovery Prepared Short Echo Time (STAIR-STE) Sequence
Authors: Ma Yajun , Jang Hyungseok , Lombardi Alecio , Hiniker Annie , Lee Roland , Chang Eric , Jak Amy , Schiehser Dawn , Simmons Alan , Head Brian , Bydder Graeme , Du Jiang
Published: August 2023

Myelin water imaging (MWI) has been proposed as a myelin-specific technique to quantify water trapped within or tightly bound to myelin bilayers and thus provides an indirect assessment of myelin content and integrity. In this study, we developed and evaluated a novel 3D short TR adiabatic inversion recovery prepared short echo time (STAIR-STE) Cones sequence for robust MWI on a clinical 3T scanner. Our results show that the 3D STAIR-STE Cones sequence robustly suppresses long-T2 intra/extracellular water signals and provides selective volumetric imaging and quantification of myelin water fraction in the whole brain.
Muscle hypertrophy in resistance training assessed with Diffusion Tensor Imaging
Authors: Mazzoli Valentina , Rubin Elka , Barbieri Marco , Schmidt Andrew , Watkins Lauren , Chaudhary Akshay , Kogan Feliks , Gold Garry
Published: August 2023

5 healthy subjects consistently performed a declined squad training routine for 3 months. Every subject received an MRI scan before undergoing the training and subsequently every month until the end of the training. We observed a decrease in AD, MD and FA over the course of training, with a significant change after 1 month. Muscle volume increased, with changes only apparent at 3 months. Changes in diffusion parameters were predictive of changes in global volume. Our study shows that DTI can be a sensitive tool to study muscle hypertrophy and could be used for early monitoring of training and rehabilitation.
Simulated fMRI responses using human Vascular Anatomical Network models with varying architecture and dynamics
Authors: Hartung Grant , Pfannmoeller Joerg , Berman Avery , Polimeni Jonathan
Published: August 2023

We utilized a synthesis algorithm to generate a vascular anatomical network model for the human cortex to act as a basis for biophysical simulations of the fMRI response. We identified key features of the vascular topology needed to generate realistic BOLD responses with this model. We used this model to show how parametric variations in vascular architecture affect the BOLD responses across cortical depths. Finally we investigated approaches to translate arteriolar dilation patterns recorded from the mouse cortex to our human model and found that they may not be capable of capturing the distinct hemodynamic response observed in human fMRI data.
Accelerating High b-Value DWI Acquisition Using a Convolutional Recurrent Neural Network
Authors: Zhong Zheng , Ryu Kanghyun , Song Jae Eun , Singhal Janhavi , Dan Guangyu , Sun Kaibao , Vasanawala Shreyas , Zhou Xiaohong
Published: August 2023

DWI can probe tissue microstructures in many disease processes over a broad range of b-values. In the scenario where severe geometric distortion presents, non-single-shot EPI techniques can be used, but introduce other issues such as lengthened acquisition times, which often requires undersampling in kspace. Deep learning has been demonstrated to achieve many-fold undersampling especially when highly redundant information is present. In this study, we have applied a novel convolutional recurrent neural network (CRNN) to reconstruct highly undersampled (up to six-fold) multi-b-value, multi-direction DWI dataset by exploiting the information redundancy in the multiple b-values and diffusion gradient directions.
Brain in a virtual Petri dish: Flattening high resolution cortex patches in MRI and histology
Authors: Gulban Omer Faruk , Huber Renzo , Wagstyl Konrad , Bolmann Saskia , Ivanov Dimo , Kay Kendrick , Goebel Rainer
Published: August 2023

High resolution imaging poses analysis challenges in the daily lives of high-resolution imaging researchers (high res. MRI, histology). One challenge is flattening patches of the cortex to study the cortical topography. We demonstrate a method that works in volume without requiring triangular meshes to represent the cortical surfaces at any stage of the algorithm. This approach for surface mapping enables mesoscopic analysis of cortical architecture. Our method is specifically developed for -but not limited to- flattening patches of the cortex. We implement our patch flattening as a C++ program and make it freely available within LayNii v2.1.0.
Unsupervised Diffeomorphic Registration for Even and Odd Echo Images with Applications to Point-of-Care MRI Reconstruction
Authors: Schlemper Jo , Dey Neel , Salehi Seyed Sadegh Mohseni , Sheth Kevin , Kimberly W. Taylor , Cullen Lorraine , Sofka Michal
Published: August 2023

We present an unsupervised deep image registration framework for MR image reconstruction. Specifically, even and odd echo images from fast spin echo-based sequence are nonlinearly registered using a convolutional network that estimates the deformation field. The registered echo images are then averaged for noise reduction. The proposed framework was evaluated across four imaging contrasts (T1w, T2w, FLAIR, and DWI) from a low-field MR scanner and was found to outperform nonlinear registration from advanced normalization tools, yielding sharper image quality and preserving important pathology features.
Detection of Laser-Associated Heating in the Brain During Simultaneous BOLD-fMRI and Optogenetic Stimulation
Authors: Luo Huiwen , Yang Zhangyan , Yang Pai-feng , Wang Feng , Reed Jamie , Chen Li Min , Gore John , Grissom William
Published: August 2023

Optogenetic stimulation with BOLD-fMRI has been applied in studies of brain circuits, by selectively exciting optical fluorophores with wavelength-specific light. However, the light used for stimulation may induce non-negligible heating effects. Because BOLD fMRI is mainly based on relatively long TE gradient-recalled echo acquisitions that are also suitable for measuring temperature changes with the proton resonance frequency (PRF) shift, we can monitor simultaneously the neural effects and laser-associated heating. We proposed a processing pipeline to calculate temperatures from BOLD images based on PRF shift thermometry and detect small temperature rises induced by laser-associated heating with general linear modeling.
Comparison of whole brain biophysical model predictions and MR thermometry measurements in healthy humans
Authors: Sung Dongsuk , Risk Benjamin , Kottke Peter , Allen Jason , Nahab Fadi , Fedorov Andrei , Fleischer Candace
Published: August 2023

To advance our understanding of thermal dynamics in the human brain, a thermal modeling framework was previously developed to facilitate temperature predictions in the absence of clinical thermometry. Here, predicted brain temperatures using our fully conserved model were compared with MR thermometry in 21 healthy human subjects. Bland-Altman plots demonstrated agreement between predictions and MR-measurements for average temperature values, but some differences were observed at the lowest and highest temperatures. Regional variations were similar between predicted and measured temperatures. We anticipate our modeling framework will form the necessary baseline for predicting injury-induced brain temperature changes in patients.
The first MR Electrical Properties Tomography (MR-EPT) reconstruction challenge
Authors: Mandija Stefano , van den Berg Cornelis
Published: August 2023

This work announces the initial design of the first Electrical Properties (EPs) reconstruction challenge and opens up the call for ideas to finalize its implementation and to define the organizing committee members. Several EPs reconstruction methods have been presented in the last decade. However, as emerged from the last EPs workshop (IMEP-Utrecht’19), testing on common data has not been performed yet, nor data are publicly available. The scope of this challenge is therefore to benchmark current reconstructions on the same data. These data will also be made available to favor benchmarking of new methods in the future.
Towards an MRI-based Prediction of Neurofibrillary Tangles
Authors: Saifullah Khalid , Tazwar Mahir , Evia Arnold , Tamhane Ashish , Bennett David , Schneider Julie , Arfanakis Konstantinos
Published: August 2023

The purpose of this work was to develop an MRI-based classifier of neurofibrillary tangles by combining ex-vivo MRI and detailed neuropathology in brain autopsies from a large number (N=878) of community-based older adults. The ex-vivo classifier was trained on volumetric, cortical thickness, subcortical shape, diffusion, and R2 measurements, as well as age and sex. The average AUC of the final classifier was 0.87. Future work will convert the ex-vivo classifier to in-vivo and test it in-vivo in independent cohorts of older adults.
Examining cerebrovascular burden across the cognitive continuum in older adults with and without evidence of amyloidosis
Authors: Rivera-Rivera Leonardo , Cody Karly , Betthauser Tobey , Koscik Rebecca , Jonaitis Erin , Cadman Robert , Hermann Bruce , Rowley Howard , Carlsson Cynthia , Chin Nathaniel , Eisenmenger Laura , Johnson Sterling , Johnson Kevin
Published: August 2023

In this study we investigated cerebrovascular health and vascular contributions to cognitive impairment in the presence and absence of amyloidosis. We employed various neuroimaging techniques including 4D-Flow, multi-delay ASL, T2-FLAIR, and structural T1 for vascular and structural biomarkers. β-amyloid (Aβ) burden was determined from PET imaging data. Data supports the notion that vascular dysfunction occurs in the presence and absence of Aβ, albeit with differing manifestations leading to cognitive decline.
Evaluation of Her-2 gene expression in endometrial carcinoma by APTw and mDIXON-Quant
Authors: Ma Changjun , Tian Shifeng , Chen Lihua , Wang Nan , Song Qingwei , Zhang Xiaoxiao , Liu Ailian
Published: August 2023

Overexpression in malignant tumors such as ovarian cancer, endometrial carcinoma (EC), etc., can cause abnormal cell proliferation and lead to malignant transformation and is related to tumor angiogenesis and tumor metastasis. This study revealed that amide proton transfer weighted (APTw) and mDIXON-Quant would be useful to evaluate the expression of Her-2 gene in EC.
Visualizing oxygen transport in real time in the murine placenta at 15.2T
Authors: Harris Talia , Neeman Michal , Frydman Lucio
Published: August 2023

We demonstrate that with the high signal to noise and sensitivity to oxygenation at 15.2 T we can visualize the transport of oxygen across the murine placenta with temporal resolution of 20s. Changes in the R2* of the placenta and embryo heart, observed upon switching from 100% O2 to 10% and switching back to 100% O2, exhibit different dynamic behavior than the maternal blood vessels, specifically a delayed response compared to the maternal blood vessels and a much slower response when switching from 10% O2 to 100% O2.
Myocarditis associated with mRNA COVID-19 vaccines: MRI findings
Authors: Starekova Jitka , Bluemke David , Bradham William , Grist Thomas , Schiebler Mark , Reeder Scott
Published: August 2023

Mass immunization campaigns continue in attempts to contain the ongoing COVID-19 pandemic. COVID-19 vaccines authorized for use in the United States include BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and JNJ-78436735 (Johnson & Johnson).

To date multiple cases of vaccine-associated inflammation of the heart have been reported. In this work, we describe cardiac MRI findings in 9 patients (adults and children) with clinical and imaging-based diagnosis of myocarditis and/or pericarditis diagnosed shortly after COVID-19 mRNA vaccination at our institution.
Lung perfusion disturbances detected with MRI in non-hospitalized post-COVID individuals with dyspnea, with sex difference.
Authors: Yu Jimmy , Granberg Tobias , Shams Roya , Petersson Sven , Szum Adrian , Sköld Magnus , Nyrén Sven , Lundberg Johan
Published: August 2023

Mechanisms underlying dyspnea in non-hospitalized patients with persistent post-COVID is unknown. Lung perfusion abnormalities have been reported in acute COVID-19, and may also be important in post-COVID. Dynamic contrast enhanced (DCE)-MRI [MS1] was applied to study lung perfusion in 28 non-hospitalized patients with persistent dyspnea 4-13 months post-COVID. Time-to-peak (TTP)[MS2] maps were numerically summarized as normalized as 2 numeric values: mean TTP and TTP ratio. Comparison was made against 22 age and sex matched controls. Perfusion abnormalities were found, with a striking sex difference with men showing more pronounced perfusion abnormalities. Perfusion abnormalities correlated with self-rated dyspnea in men.
Regional assessment of cerebral oxygen extraction fraction in neonates with hypoxic-ischemic-encephalopathy: a pilot study
Authors: Jiang Dengrong , Golden W. , Tekes Aylin , Parkinson Charlamaine , Soares Bruno , Meoded Avner , Lu Hanzhang , Northington Frances , Liu Peiying
Published: August 2023

Hypoxic-ischemic-encephalopathy (HIE) is the leading cause of neonatal mortality and severe neurological impairment in childhood. Quantification of cerebral oxygen-extraction-fraction (OEF) in neonates with HIE may provide valuable information to guide the treatment and predict clinical outcome. In this pilot study, we used a novel MRI technique, accelerated-T2-relaxation-under-phase-contrast (aTRUPC), to measure regional OEF in neonates with HIE. We demonstrated a trend towards lower cortical OEF in HIE neonates compared to healthy controls. In addition, neonates with severer brain injury had lower cortical OEF. These findings suggest that regional OEF measurement may be useful in evaluating cerebral injuries in HIE.
Bayesian Estimation of Diffusivity Spectra: Application to Prostate Diffusion MRI
Authors: Wells William , Maier Stephan , Westin Carl-Fredrik
Published: August 2023

There is great interest to quantify the spectrum of diffusivities that underlie the observed diffusion signal decay; separate tissue compartments can be identified by their spectral peaks. This spectrum is defined by the inverse Laplace transform, but unfortunately this transform is very sensitive to noise omnipresent in diffusion MRI. We present a Bayesian method of inverse Laplace transform that uses Gibbs sampling to provide spectra along with an estimate of the noise related uncertainty in the spectra; this uncertainty information is valuable in interpreting the results. This is applied to multi-b high SNR endorectal coil diffusion data of the prostate.
Mapping the myelin bilayer with short-T2 MRI: Validation studies
Authors: Baadsvik Emily Louise , Weiger Markus , Froidevaux Romain , Faigle Wolfgang , Ineichen Benjamin Victor , Pruessmann Klaas Paul
Published: August 2023

Various techniques for myelin mapping based on signal from the lipid-protein bilayer have been proposed, and a common way of validating these techniques is using ex-vivo tissue samples. However, it is still unclear to what extent experimental factors such as tissue storage conditions and processing affect MR signal. In this work, we investigate how long-term deep-frozen storage impacts tissue signal, and evaluate whether signal component mapping is feasible in non-D2O-exchanged samples. We also determine whether animal tissue can act as a substitute for human tissue and investigate signal differences between white and grey matter.
Towards a gold standard for fiber orientations in the brain: Validating dMRI using scattered light and X-ray imaging
Authors: Georgiadis Marios , Menzel Miriam , Gräßel David , Rajkovic Ivan , Born Donald , Axer Markus , Zeineh Michael
Published: August 2023

Generating a detailed network model of the brain requires a correct mapping of fiber orientations. Diffusion MRI is sensitive to neuronal alignment, yet each voxel contains hundreds of axons and other structures. Light and X-ray scattering can reveal more detailed information about nerve fibers, with much higher resolution and specificity respectively. Here we combine two methods, namely Scattered Light Imaging (SLI) and 3D-scanning small-angle X-ray scattering (3D-sSAXS), aiming to provide a micrometer-resolution gold standard for fiber orientation imaging. We compare that to high-resolution diffusion MRI of a region with challenging fiber orientations, the corona radiata, in human and non-human primates.
Diffusion-filtered imaging: Towards tissue-specific diffusion-MRI contrasts by combinations of tensor-valued diffusion encoding
Authors: Szczepankiewicz Filip , Vis Geraline , van Westen Danielle , Westin Carl-Fredrik , Sundgren Pia , Nilsson Markus
Published: August 2023

Diffusion weighted imaging has been used both as a radiological tool that provides a simple biomarker without quantitative qualities, and more recent efforts have endeavored to make it quantitative by fitting of biophysical models or representations. In this work, we explore the novel radiological contrasts that can be generated by introducing tensor-valued diffusion encoding. Unlike most model-based approaches, these contrasts can be produced by rapid acquisition schemes and they produce novel contrasts that may contribute new diagnostic and radiological biomarkers.