bluuebunny/crossref_metadata_2025 huggingface dataset:
External Dynamic InTerference Estimation and Removal (EDITER) for low field MRI
Authors: Srinivas Sai Abitha , Cauley Stephen , Stockmann Jason , Sappo Charlotte , Vaughn Christopher , Wald Lawrence , Grissom William , Cooley Clarissa
Published: August 2023

Point of care MRI requires operation outside of an MR shielded room where electromagnetic interference can degrade image quality. To address this, we demonstrate a self-calibrated generalized dynamic model to retrospectively remove time-varying external interference. The method uses data acquired from multiple Electromagnetic Interference (EMI) detectors simultaneous with the primary MR coil. We test the approach both in a controlled EMI setting on an 80mT Halbach scanner and an uncontrolled real-world EMI setting on a 47.5mT permanent magnet open MRI system.
Simultaneous FDG-PET and MRI-based connectivity analysis for the detection of epileptogenic zones in non-lesional epilepsy patients
Authors: Lisazo Clara , Bove Natalia Massaccesi , Zanchi Daniela , Pópolo María Del , Fino Daniel , Nicolini Federico González , Mosconi Sergio , Ariza Pedro , Padín Trinidad Gonzalez , Otoya Raúl , Isoardi Roberto , Doring Thomas , Moguilner Sebastián
Published: August 2023

Detecting epileptogenic zones (EZ) in subjects with non-lesional epilepsy can represent a challenge, and it involves the analysis of data from various diagnostic procedures. In this study, seed-based structural and functional connectivity matrices were obtained from DWI and resting-state fMRI for each patient and compared with a control group. Then, we assessed whether significantly different regions (p<0.001) coincided with foci of abnormal metabolism on PET images, and if these ROIs corresponded with the subject’s EZ. This reduced the false positive rate and improved specificity of the connectivity analysis, optimizing EZ localization in patients with non-lesional epilepsy.
Comparing sliding window correlation and instantaneous phase coherence in fMRI dynamic functional connectivity analysis
Authors: Fonseca Cláudia , Esteves Inês , Xavier Marta , Fouto Ana , Ruiz-Tagle Amparo , Silva Nuno A. , Nunes Rita G. , Gil-Gouveia Raquel , Cabral Joana , Figueiredo Patrícia
Published: August 2023

Sliding window Pearson correlation (SW) is the most commonly used approach for estimating dynamic functional connectivity (dFC). However, instantaneous phase coherence (PC) has gained popularity as it yields frame-by-frame dFC estimates. This work aimed to compare both metrics by analysing the mean lifetime, probability of occurrence and spatial similarity of dFC states with the canonical resting-state networks (RSNs). We found that the state lifetimes increase in SW compared to PC and with window length, worsening the detection of RSNs for smaller datasets. These findings indicate that the temporal blurring induced by SW compromises the ability to detect faster network dynamics.
First evidence of a link between topology and neurophysiological properties of brain sub-networks.
Authors: Monteverdi Anita , Palesi Fulvia , Wheeler-Kingshott Claudia Gandini , D'Angelo Egidio
Published: August 2023

A comprehensive assessment of multiple resting-state networks is still lacking and the characterization of their excitatory/inhibitory (E/I) balance is an open field of research. In this exploratory work we performed a first characterization of the E/I balance in resting-state networks (visual, somatomotor, attention, limbic, frontoparietal, DMN) both in healthy and neurodegenerative conditions (Alzheimer’s Disease, Frontotemporal Dementia, Amyotrophic Lateral Sclerosis) taking advantage of a Virtual Brain based approach. Our results provided a new strategy to simultaneously characterize multiple networks at single-subject level, deepening their E/I balance and opening new perspectives for biomarkers research.
Alignment and joint recovery of multi-slice free-breathing cardiac cine using manifold learning
Authors: Zou Qing , Ahmed Abdul Haseeb , Nagpal Prashant , Priya Sarv , Schulte Rolf F. , Jacob Mathews
Published: August 2023

Free-breathing cardiac cine methods are needed for pediatric and chronic obstructive pulmonary disease (COPD) subjects. Multi-slice acquisitions can offer good blood-myocardium contrast, and hence preferred over 3D methods. Current approaches independently recover the slices, followed by post-processing to combine data from different slices. In this work, a deep manifold learning scheme is introduced for the joint alignment and reconstruction of multi-slice dynamic MRI. The proposed scheme jointly learns the parameters of the deep network as well as the latent vectors for each slice, which captures the motion induced dynamic variations, from the k-t space data of the specific subject.
MR chemical exchange saturation transfer study of myocardium creatine dynamic change in an acute infarct porcine model
Authors: Xie Chuan-Miao , Liu Jie , Zhao Jia-Lei , Liu Qi , Xu Jian , Zheng Li-Yun , Liu Xin , Zheng Hairong , Wu Yin
Published: August 2023

This study investigated the dynamic alteration of myocardium creatine in infarct hearts using CEST MRI. Seven pigs underwent cine, Cr CEST and LGE imaging 3 and 14 days after MI. Significant increase of stroke volume and ejection fraction and decrease of infarct angle were observed at day 14 compared to that at day 3. Meanwhile, Cr CEST signals increased significantly in the infarct and its adjacent myocardium, and negatively correlated with infarct angle. The improved metabolic activity was associated with function recovery, indicating that Cr CEST MRI is promising to provide complementary information for heart remodeling at the molecular level.
Dynamic UTE molecular MR imaging targeting pulmonary fibrogenesis in a model of left ventricular dysfunction
Authors: Moon Brianna , Zhou Iris , Ning Yingying , Shuvaev Sergey , Le Fur Mariane , Chen Yin-Ching , Akam Eman , Weigand-Whittier Jonah , Rotile Nicholas , Drummond Matthew , Boice Avery , Zygmont Samantha , Warburton Rod , Fanburg Barry , Penumatsa Krishna , Caravan Peter
Published: August 2023

Group 2 pulmonary hypertension is a complication of chronic left ventricular dysfunction. During the early stages of the disease activity there is an accumulation of extracellular matrix molecules and an increase in allysine content. Molecular MR imaging with an allysine-targeted fibrogenesis probe shows increased lung-to-muscle ΔCNR within the lungs of transverse aortic constriction (TAC)-induced left ventricular dysfunction animal models compared to control animals, which corresponded to increased lung and right ventricle weight, and elevation of fibrogenesis biomarkers (hydroxyproline and allysine).
Comparison of T2*-weighted image analysis with quantitative T2* maps in different stages of myocardial infarction in a pig model study with 7T cMRI
Authors: Aures Julia , Terekhov Maxim , Lohr David , Bille Maya , Hock Michael , Elabyad Ibrahim , Schnitter Florian , Bauer Wolfgang , Hofmann Ulrich , Schreiber Laura
Published: August 2023

In the field of ultra-high field MRI, T2* mapping is a promising technique for the non-invasive assessment of myocardial pathophysiology. Preclinical studies have already shown the potential to detect structural changes in infarcted myocardial tissue. Quantitative T2* imaging is very demanding with regard to measurement- and postprocessing time. Hence, we compared in this study the simpler and faster grayscale analysis of T2*-weighted images with quantitative T2* techniques. This was done in early and late acute infarct healing stages in a large animal model by comparing T2* maps with grayscale T2*-weighted images.
Serial in vivo 19F MRI tracks the immune cell response to bioscaffolds implanted in a rat model of stroke
Authors: Modo Mike , Ghuman Harmanvir , Azar Reem , Krafty Ryan , Badylak Stephen , Hitchens T.
Published: August 2023

Regenerative medicine is increasingly investigating how an initial pro-inflammatory response convert to a pro-repair response. Implantation of bioscaffolds exploits this mechanism and allows tissue to regrow in large defects. Even the brain, which is known to not regrow tissue spontaneously, can regenerate lost tissue after implantation of a inductive bioscaffold. Little is known about how immune cells respond to the implantation of a bioscaffold. We here characterized the acute spatiotemporal dynamics of immune cell infiltration into the brain and a bioscaffold by tagging immune cells with perfluorocarbon nanoemulsions for detection by 19F MRI and anatomical context using 1H MRI.
Multimodal apparent diffusion model provides comprehensive analysis of clinical subacute stroke lesions
Authors: Damen Frederick , Su Changliang , Mocan Burce Ozgen , Vályi-Nagy Tibor , Jiang Rifeng , Cai Kejia
Published: August 2023

We present our initial findings of applying Multimodal Apparent Diffusion (MAD) MRI, including b-values up to 10,000 s/mm2, to analyze subacute stroke lesions for the characterization of stroke lesions based on micro-environment biomarkers in order to guide treatment in clinics. MAD model is able to separate the acquired diffusion weighted signal into flow, and, unimpeded (fluid), hindered, and restricted apparent diffusion components. Significant differences were found in MAD parameters between lesions and normal appearing white matter. Fraction of unimpeded diffusion significantly increased. Hindered diffusion was significantly lower in lesions. On the other hand, restricted diffusion was significantly higher.
Comparative Study on MR Imaging Quality of Anterior Talofibular Ligament based on Carotid Plaque Special Surface Coil
Authors: Liao Yunjie , Zhao Chen
Published: August 2023

Ankle sprain is a common athletic injury. Most patients with acute ankle sprain could not be treated properly, without precise diagnosis. Conventional Magnetic Resonance Imaging (MRI) sequences, like T1WI and T2WI, could not provide diagnostic proof as accurately as possible. Proton density weighted imaging (PDWI) collaborating with fat saturation (FS) could be a better alternative to detect the lesions. A comparative study was established, to investigate the performance of 4 sequences, with 8-channel carotid special surface coil. The results showed that PDWI-FS may be the best choice on diagnosis of ankle injuries among 4 sequences
Bi-component dictionary for efficient quantification of fat fraction and water T1 via MR Fingerprinting
Authors: Slioussarenko Constantin , Baudin Pierre-Yves , Reyngoudt Harmen , Marty Benjamin
Published: August 2023

In the field of neuromuscular disorders (NMD), fat fraction (FF) is an established biomarker of disease severity and water T1 (T1H2O) has been shown to be a potential biomarker of disease activity. Those can be efficiently estimated through Magnetic Resonance Fingerprinting. However for muscle studies water-fat separation and FF quantification increase drastically the size of the dictionary and pattern matching time. We introduce here a bicomponent dictionary where water and fat signals are stored separately. This approach allows improving MRF performance and increasing the accuracy of FF quantification.
Simultaneous J-difference editing of GABA and GSH with extended echo-times using ExTE-HERMES
Authors: Truong Peter , Near Jamie
Published: August 2023

J-difference editing techniques, such as MEGA-PRESS, are often used to detect gamma-aminobutryic acid (GABA) and glutathione (GSH). However, two separate scans are needed to acquire both metabolites. The HERMES editing scheme does address this issue, allowing simultaneous acquisition of GABA and GSH. Even then, there are limitations as the optimal echo time (TE) can only be set for one metabolite at the expense of lower editing efficiency for the other. We propose the Extended TE (ExTE) HERMES editing scheme, which allows us to acquire edited spectra at TE=120ms, ensuring maximum GSH signal while still providing efficient GABA editing.
Cerebral Blood Flow Quantification using Pseudo-continuous Arterial Spin Labeling at 7T MRI
Authors: Alkhateeb Salem , Kim Tae , Aizenstein Howard , Ibrahim tamer
Published: August 2023

The feasibility of implementing pCASL technique at 7T MRI as a routine protocol uncovers the difficulties and challenges that need to be overcome and taking into consideration the many variables that need to be addressed before running the sequence. We were able to successfully implement pCASL sequence with satisfactory results. CBF quantification for the 4 volunteers was within clinical normal ranges and CBF mapping agrees with published data. Future work will include the inclusion of neck coil module for improving labeling efficiency.[GU1] Where is figure 4 referenced [GU1] Please add the references
Robust and Motion-Insensitive Approach to Diffusion-Weighted Half-Fourier Acquisition Single-Shot Turbo Spin-Echo Imaging
Authors: Arbabi Aidin , Khlebnikov Vitaliy , Norris David. G. , Marques Jose P.
Published: August 2023

Half-Fourier acquisition single-shot turbo spin-echo diffusion-weighted (DW-HASTE) is a clinically established magnetic resonance imaging tool for the detection of small lesions, particularly cholesteatoma. However, in the standard approach, half of the available signal is sacrificed through displacing one echo parity out of the acquisition window to fulfil the Carr-Purcell-Meiboom-Gill condition. We present a selective parity approach to tackle this problem. The proposed method features a near full sensitivity, a low specific absorption rate for long echo trains, and about two-fold increase in signal-to-noise ratio, compared to the manufacturer's method under the same conditions.
A modular software “sequence building block” for interleaved MRS and MRI acquisition on 7T Terra
Authors: Karkouri Jabrane , Wickens Christopher , Atkinson Daniel , Rodgers Christopher
Published: August 2023

In this work, we present a software “sequence building block” that enables interleaving MRS acquisitions (X-nuclear or 1H) inside a base imaging sequence (typically 1H) on the Siemens 7T Terra platform. We envisage using this approach for dynamic B0 shim and frequency offset correction to mitigate breathing artefacts in 31P-MRSI of heart and liver.
Susceptibility-induced B-field inhomogeneity of undulating axons and effects on the DWI signal
Authors: Winther Sidsel , Lundell Henrik , Dyrby Tim
Published: August 2023

Magnetic susceptibility induces morphology- and orientation-dependent perturbations of the $$$B_0$$$-field and hence the DWI signal. At the micro-structural scale of brain white matter, the main contribution to these perturbations comes from myelin. To understand how the perturbations are shaped by the intrinsically undulating morphology of axons, observed in 3D reconstructions of synchrotron imaging and electron microscopy, we have implemented a framework that enables us to systematically study how undulation affects the orientation-dependency of susceptibility-induced B-field inhomogeneity, and how this affects the DWI signal - both in the intra- and extra-axonal compartments.
Evaluating Within-Subject Test-Retest Replicability of Free-Water Corrected and Uncorrected Multi-Shell Diffusion MRI Measures.
Authors: Mishra Virendra , Pasternak Ofer , Sreenivasan Karthik , Cordes Dietmar
Published: August 2023

Free-water (FW) estimation could be improved with higher spatial resolution diffusion MRI (dMRI) data acquired at multiple shells. However, the effect of multi-shell protocol features on the accuracy of estimating FW and FW-corrected fractional anisotropy (FA) across the brain structures is currently unknown. We evaluated test-retest reproducibility of FW and FW-corrected FA across 20 major white-matter tracts across four dMRI protocols, two protocols with ADNI-3 and two protocols with HCP sequences. Our analysis suggests higher spatial resolution HCP-style dMRI data acquisition with correction of FW-estimation could be reliably performed in routine clinical investigations.
MRSI Processing and Simulation Toolbox in the FID Appliance (FID-A)
Authors: Kadota Brenden , Strasser Bernhard , Oakden Wendy , Near Jamie
Published: August 2023

Magnetic resonance spectroscopic imaging (MRSI) is a biomedical imaging tool that enables spatial mapping of metabolite signals in vivo. Dedicated software for MRSI data preprocessing, image reconstruction, visualization and simulation is vital to the development and routine application of MRSI but relatively few tools are available for this purpose. We present an open source toolbox in MATLAB for preprocessing, visualization and simulation of MRSI data. The processing toolbox includes functions for importing data, coil combination, B0 inhomogeneity correction, and non cartesian reconstruction, while the simulation toolbox can simulate MRSI acquisitions with arbitrary input k-space trajectories.
Iterative RAKI with complex-valued convolution for improved image reconstruction with limited training samples
Authors: Dawood Peter , Blaimer Martin , Breuer Felix , Burd Paul , Homolya István , Jakob Peter , Oberberger Johannes
Published: August 2023

Recently, the Parallel Imaging method GRAPPA has been generalized by the deep-learning method RAKI, in which Convolutional Neural Networks are used for non-linear k-space interpolation. RAKI uses scan-specific training data, however, due to its increased parameter-space, its reconstruction quality may deteriorate given a limited training-data amount. We evaluate an approach that includes augmented training-data via an initial GRAPPA k-space reconstruction, and weights refinement by iterative training. Thereby, severe residual artefacts are suppressed in RAKI, while preserving its resilience against g-factor noise enhancement in GRAPPA for standard 2D imaging at medium accelerations, for strongly varying contrast between training- and interpolation-data, too.
Concept of a symmetry-guided single-layer neural network for image reconstruction of undersampled radial-MRI k-space data.
Authors: Ypma Sjoerd , Maatman Ivo , Caan Matthan , Karkalousos Dimitris , Maas Marnix , Scheenen Tom
Published: August 2023

Undersampled k-space data reconstruction results in aliasing artifacts. Compressed sensing theory enables image reconstruction by using a priori knowledge in the form of regularization. Increasingly, Machine Learning methods are used to learn the regularization from data itself, but these methods can result in unstable reconstructions.

We propose a translation equivariant single-layer neural network for reconstruction of radially measured k-space data. By exploiting translation symmetry, it can learn from randomly simulated data while still being applicable to in-vivo measurements. We tested robustness to small perturbations and reliability of the reconstruction of unexpected objects.
Triple Multinuclear Probe: Expanding the Throughput and Versatility of a dDNP Polarizer
Authors: Lê Thanh Phong , Wiström Emma , Hyacinthe Jean-Noël , Capozzi Andrea
Published: August 2023

Low throughput is one of dDNP main shortcomings. Here, we present the design and performance of a triple DNP probe, which not only allows multiple samples to be hyperpolarized simultaneously, but also to distinctly monitor the solid-state polarization of each sample, even when prepared with different nuclei and radicals. This versatile high throughput probe allows parallel solid-state sample characterization, as well as sequential injections of distinct tracers to probe multiple biomarkers, thus enabling more advanced in-vivo experimental designs.
Direct detection of 2HG and glutamate production using hyperpolarized [1-13C-5-12C]-a-ketoglutarate in cell and in vivo glioma models
Authors: Hong Donghyun , Kim Yaewon , Mushti Chandrasekhar , Minami Noriaki , Gillespie Anne Marie , Viswanath Pavithra , Swenson Rolf E. , Vigneron Daniel B. , Ronen Sabrina M.
Published: August 2023

Mutant IDH leads to 2HG production, which drives glioma development. 13C MRS monitoring of hyperpolarized [1-13C]α-ketoglutarate (αKG) metabolism to 2HG and glutamate provides a non-invasive assessment of the IDH mutation and normal metabolism, respectively. However, monitoring 2HG production in vivo is challenging because its resonance is within 0.1 ppm of the natural abundance [5-13C]αKG signal of the [1-13C]αKG substrate. Here, we utilized [1-13C-5-12C]αKG, which eliminated the [5-13C]αKG peak. This new approach, combined with an optimized sequence, made it possible to readily monitor the production of both 2HG and glutamate in a patient-derived glioma animal model and in normal brain.
Parallel imaging of hyperpolarized 13C MRI using 23Na sensitivity profiles
Authors: Olin Rie , Sánchez-Heredia Juan , Grist James , Wang Wenjun , Bøgh Nikolaj , Zhurbenko Vitaliy , Hansen Esben , Schulte Rolf , Tyler Damian , Laustsen Christoffer , Ardenkjær-Larsen Jan
Published: August 2023

Parallel imaging can aid hyperpolarized 13C MRI in extracting more information in the limited time window of the hyperpolarized signal. Using a dedicated, flexible 13C receive coil design with coupling coefficients matched for both 13C and 23Na, sensitivity profiles for reconstruction can be acquired at the 23Na frequency. We demonstrate this method in two hyperpolarized in vivo experiments involving pig kidneys and human brain using a two-times accelerated 3D blipped stack-of-spirals sequence with dual-resolution. The results show good SNR, coverage, and resolution. The method is promising for integrating and automating parallel imaging for hyperpolarized 13C MRI.
Seiffert spirals for hyperpolarized 13C MRI with efficient k-space sampling and flexible acceleration
Authors: Olin Rie , Speidel Tobias , Sánchez-Heredia Juan , Hansen Esben , Laustsen Christoffer , Hanson Lars , Rasche Volker , Ardenkjær-Larsen Jan
Published: August 2023

The Seiffert spirals trajectory has favorable properties for hyperpolarized 13C MRI. It allows for high degrees of undersampling and combined conjugate gradient compressed sensing SENSE reconstruction when multi-channel arrays are used. The trajectory was evaluated in simulations, in phantom, and for in vivo hyperpolarized 13C-urea MRI of pig kidneys with retrospective undersampling and high temporal resolution. For single-frequency imaging, flexible acceleration is achieved through reconstruction based on any number and combination of spiral arms. Simulations demonstrated noise-like aliasing and successful reconstruction. The in vivo experiment showed improved characterization of urea dynamics after undersampling. The reconstruction algorithm can be further improved.
Hepatic and renal ketogenesis of hyperpolarized (1-13C)butyrate: functional evidence of metabolic zonation
Authors: Yoshihara Hikari , Gruetter Rolf , Hoerr Verena
Published: August 2023

Ketones bodies are an important metabolic fuel, and butyrate is a ketogenic short-chain fatty acid. We report the metabolism of hyperpolarized (1-13C)butyrate in the rat kidney and liver. The main metabolites in the kidney include [1-13C]acetoacetate, [1-13C]butyrylcarnitine and [5-13C]glutamate, and [1-13C]acetylcarnitine, 3-hydroxy[1-13C]butyrate, [5-13C]citrate and [3-13C]acetoacetate are also detectable. Fasting results in significantly lower butyrylcarnitine/[1-13C]acetoacetate and glutamate/[1-13C]acetoacetate ratios. Ketogenesis is observed in the liver and the [1-13C]butyrylcarnitine + [1-13C]acetoacetate signal normalized to butyrate is higher with fasting. The unexpectedly low 3-hydroxy[1-13C]butyrate signals are functional evidence of metabolic zonation, with acetoacetate production and reduction occurring in different cells.
In-vivo Imaging of hyperpolarized and purified Fumarate at 11.7 T
Authors: Speidel Tobias , Knecht Stephan , Gierse Martin , Lobmeyer Tobias , Winter Gordon , Löffler Jessica , Fellermann Maximilian , Schwartz Ilai , Barth Holger , Rasche Volker
Published: August 2023

Hyperpolarized [1-13C] fumarate has been shown to be a reliable imaging biomarker for monitoring cellular necrosis with conversion of [1-13C]fumarate to [1-13C]malate via Fumarate hydratase. However, the inherently low 13C-sensitivity limits biomedical applications with a need for accessible and low-cost hyperpolarization methods.

In this abstract we show that parahydrogen-induced polarization methods can overcome these limitations by providing highly polarized and purified [1-13C]fumarate as a non-toxic perfusion agent with the capabilities of acting as a biomarker of cell necrosis in metabolic 13C MRI.
MultiNet CAIPIRINHA: accelerated 1H MRSI with 1-step neural network reconstruction based on augmented MRSI training data
Authors: Chan Kimberly , Henning Anke
Published: August 2023

We have shown that MultiNet, a neural-network-based image reconstruction, can reconstruct variable-density k-space undersampling schemes to decrease MRSI acquisition times. This used a 4-step method where points are predicted by 4 successively-applied neural-networks off both acquired and previously predicted k-space points. Herein, a 1-step method where points are only predicted off acquired k-space points to reduce reconstruction error was explored. This method was trained using a new augmented MRSI training set and compared to the 4-step reconstruction of new CAIPIRINHA-based schemes and the original schemes. The new 1-step reconstruction method was found to increase SNR and improve metabolic maps.
Replicability of 1H MR spectroscopic imaging in mild traumatic brain injury
Authors: Chen Anna , Gerhalter Teresa , Dehkharghani Seena , Peralta Rosemary , Adlparvar Fatemeh , Gajdošík Martin , Tordjman Mickael , Zabludovsky Julia , Sheriff Sulaiman , Ahn Sinyeob , Babb James , Bushnik Tamara , Zarate Alejandro , Silver Jonathan , Im Brian , Wall Stephen , Madelin Guillaume , Kirov Ivan
Published: August 2023

1H-MRS has the potential to provide biomarkers for mild traumatic brain injury (mTBI), a diagnosis in which damage is often imaging-occult, but a lack of replicability and reproducibility studies hampers clinical translation. Here, we tested the replicability of previous MRSI results in mTBI with a different patient cohort. Five out of seven hypotheses were consistent with previous work, with key findings of globally diffuse white matter (WM) injury and limited gray matter injury. However, we report differences in choline and creatine, not N-acetyl-aspartate. Correlations were found between metabolite levels in WM and both symptomatology and neuropsychological testing.
Construction of a Tx/Rx body coil on a rotatable patient capsule for MR-guided particle therapy
Authors: Dietrich Kilian , Klüter Sebastian , Debus Jürgen , Dinkel Fabian , Echner Gernot , Ladd Mark , Platt Tanja
Published: August 2023

An RF body coil compatible with particle therapy was built for a clinical MR scanner at 1.5T with a rotatable patient capsule. The attenuation of 1H+ and 12C6+ ions due to inelastic scattering was calculated for different materials to estimate the detrimental effects of the RF coil on the particle beam. The imaging capabilities could be demonstrated with phantom measurements at different flip angles, and corresponding transmit and receive characteristics were analyzed and compared to electromagnetic field simulations for both a horizontal and a tilted position of a phantom.
Improved high-resolution fMRI image quality with simultaneous multislice VFA-FLEET using a novel multi-kernel slice-GRAPPA algorithm
Authors: Berman Avery , Setsompop Kawin , Witzel Thomas , Grissom William , Polimeni Jonathan
Published: August 2023

We propose a novel slice-GRAPPA reconstruction algorithm, termed multi-kernel slice-GRAPPA (mks-GRAPPA), to tackle the challenge of reconstructing high spatial resolution segmented multi-shot EPI data for fMRI. This is particularly relevant for the recently proposed Variable-Flip-Angle “FLEET” pulse sequence. For a segmentation factor, S, by training 2×S slice-GRAPPA kernels, rather than one, we demonstrate significant improvements in image quality metrics under a wide range of protocols. The multitude of kernels account for static signal discontinuities within and across segments in multi-shot EPI. In the SNR starved regime of high-res fMRI, mks-GRAPPA allows us to recover a significant portion of lost tSNR.
Endogenous assessment of myocardial injuries using T1-rho mapping: comparison to T1 mapping, T2 mapping and late gadolinium enhancement imaging
Authors: Bustin Aurelien , Pineau Xavier , Sridi Soumaya , Jaïs Pierre , Stuber Matthias , Cochet Hubert
Published: August 2023

Myocardial T1-rho (T1ρ) mapping is a promising technique which reveals new insights about the macromolecular content of biological tissues. The idea that T1ρ mapping can be used to quantify myocardial fibrosis without contrast agent opens the door to new clinical capabilities. Yet, the tissue determinants driving T1ρ changes are still unclear, and the applicability of the technique to the broad spectrum of myocardial injuries remains uncharted territory. In the present study, we aim to identify clinical correlates of myocardial T1ρ and to examine how myocardial T1ρ values change under various clinical scenarios.
Automated black-blood late gadolinium enhancement cardiac imaging through explainable user-independent inversion time selection
Authors: Maillot Aurelien , Sridi Soumaya , Pineau Xavier , André-Billeau Amandine , Hosteins Stéphanie , Nuñez-Garcia Marta , Sermesant Maxime , Cochet Hubert , Stuber Matthias , Bustin Aurelien
Published: August 2023

Black-blood late gadolinium enhancement (LGE) imaging techniques have been introduced to improve the poor scar to blood contrast of bright-blood LGE, especially for subendocardial myocardial infarction. These techniques heavily rely on the manual selection of the optimal inversion time (TI) for blood nulling which makes them operator-dependent, reduce their reproducibility and decrease clinical workflow efficiency. In this work, we investigate whether an explainable image processing technique can be employed for automated TI selection to enable fully automated black-blood LGE.
M-Estimator for Robust Parameter Fitting in Quantitative Cardiac T1 Mapping
Authors: Zhao Yidong , Yang Changchun , Huang Lu , Xia Liming , Weingärtner Sebastian , Tao Qian
Published: August 2023

Quantitative cardiac T1 mapping involves nonlinear parameter estimation after MR acquisition. The widely used minimum mean square error (MMSE) estimator assumes Gaussian additive noise, and can be sensitive to outliers of non-Gaussian nature, such as those caused by cardiac motion. In this work, we propose to apply robust loss functions, which are part of the M-estimator family, with increased robustness to outliers. Experiments on MOLLI and SAPPHIRE sequences showed that the M-estimators were able to improve the T1 estimation robustness, significantly reducing the standard deviation (SD) error of the estimated T1 map in comparison to MMSE.
Single breath-hold native myocardial T1 and T2 mapping using SENSE and a 72-channel cardiac receive array.
Authors: Klarenberg Hugo , Gosselink Mark , Leiner Tim , Coolen Bram , Nederveen Aart , Bakermans Adrianus , Lamb Hildo , Boekholdt S. Matthijs , Strijkers Gustav , Froeling Martijn
Published: August 2023

Single breath-hold native MOLLI T1 mapping in 3 slices is possible using SENSE=4 & 6 and a 72 channel receive array. T1 values in 16 segments of the 17-segment AHA model (excluding the apical segment) were similar compared to SENSE=2 using 3 breath-holds measured in 20 healthy subjects (10 female). Myocardial T2 GRaSE mapping with fewer breath-holds in 3 slices is possible, though at the expense of decreased accuracy of the T2 values in specific segments.
The importance of optimized post-processing for accurate T1-mapping using shMOLLI: A phantom and in vivo evaluation at 3 T
Authors: Andersson Linnéa , Svensson Pär-Arne , De Lange Charlotte , Lagerstrand Kerstin
Published: August 2023

We demonstrate the effect of not having relevant post-processing algorithm implemented when using the shMOLLI scan sequence for T1-mapping of myocardium and propose an optimization strategy where we use only the five first acquired images in post-processing. Phantom and in vivo measurements of T1-values in myocardium and blood pool in a pediatric population show the importance of using relevant post-processing: a large heart rate dependence is introduced in estimated T1-values without it. This heart rate dependency can, however, be effectively reduced by using only the five first acquired images in post-processing, resulting in measurements with high accuracy.
Imaging cardiac purkinje fibers network using ihMT imaging on a clinical 1.5T scanner
Authors: Magat Julie , Delcey Marylène , Toupin Solenn , Troalen Thomas , Soustelle Lucas , Hertanu Andreea , Girard Olivier , Duhamel Guillaume , Quesson Bruno
Published: August 2023

The Purkinje fiber network (PF) enables electrical impulses throughout the heart and initiate cardiac contraction. To characterize this network in 3D is of high importance to better understand cardiac arrhythmia mechanisms. This preliminary work performed at 1.5T using a high-resolution coil aims to evaluate the inhomogeneous Magnetization Transfer imaging method to visualize PF and differentiate them from the myocardium in a clinical setup. For the first time we obtained an ihMT contrast between a conductive fiber and myocardium at 1.5T on ex vivo sample with an isotropic resolution of 500 µm.
Static and dynamic parallel transmission (pTx) for human cardiac MRI at 14.0 T
Authors: Nurzed Bilguun , Eigentler Thomas , Aigner Christoph , Schmitter Sebastian , Niendorf Thoralf
Published: August 2023

Transmission field inhomogeneities at ultrahigh and extreme field MRI can be offset by using static or dynamic pTx. Responding to the challenges and recognizing the opportunities of cardiac MRI, this abstract examines the feasibility of parallel transmission (pTx) using fractionated dipole (FRD) RF array configurations for static and dynamic B1+ homogenization of the heart at 7.0T and 14.0T. Our results reveal that static pTx provides limited performance at 14.0 T but dynamic pTx enables uniform excitation of the heart at 14.0T. This finding is heartening and provides the technical foundation for explorations into cardiac MRI at 14.0T.
Relationships Between Muscle Function, Muscle Fat, and Architecture Measured by MRI in Vivo
Authors: Gordon Joseph , Remillard Nicholas , Arieta Luke , Nagarajan Rajakumar , Damon Bruce , Kent Jane
Published: August 2023

The purpose of this work was to investigate the associations between skeletal muscle function and markers of fat content, diffusivity, and architecture. Combining MR techniques that measure muscle structure in vivo with muscle strength measures can elucidate mechanisms other than muscle size that may contribute to functional impairments. This study identified variables (e.g., fascicle length, muscle curvature, pennation angle, fat fraction) that are worthy of investigation in conjunction with functional parameters in future research, and highlighted assessment of muscle function across various contraction types and velocities.
Evaluating Structural and Functional Lower-limb Asymmetries through MRI and Wearable Sensors
Authors: Schmidt Andrew , Rubin Elka , Ko Michael , Watkins Lauren , Barbieri Marco , Hales Laurel , Gold Garry , Delp Scott , Kogan Feliks , Mazzoli Valentina , Chaudhari Akshay
Published: August 2023

Current evaluation methods of rehabilitation following acute musculoskeletal injuries are largely qualitative. MRI and biomechanics tools can provide sensitive, quantitative measures of knee joint and lower extremity muscle changes, but the relationship between MRI and gait markers is not well characterized. We combined an MRI protocol with wearable sensors in healthy participants to characterize the relationship between gait kinematic asymmetries and thigh muscle and cartilage morphology and composition. We show that vastus lateralis (VL) muscle microstructure assessed via Diffusion Tensor Imaging (DTI) may be sensitive to gait variations. Future work may further explore these correlations in patients with musculoskeletal injuries.
Effect of Resistance Training on Lower-Extremity Gait Kinematics and Muscle Morphology
Authors: Ko Michael , Schmidt Andrew , Rubin Elka , Watkins Lauren , Barbieri Marco , Hales Laurel , Gatti Anthony , Gold Garry , Kogan Feliks , Delp Scott , Mazzoli Valentina , Chaudhari Akshay
Published: August 2023

Gait retraining has been studied as an intervention to improve osteoarthritis symptoms but has a variety of limitations. An alternative approach may be muscle strengthening interventions that have known impacts on gait changes. However, limited studies have examined the quantitative relationships between muscle strengthening and gait. Here, we combine a rapid MRI protocol with wearable sensors to determine that a 12-week exercise intervention induced significant changes in both quadricep muscle morphology and gait kinematics. Morphological changes in different muscles were related to different kinematic changes, which may inform future strengthening interventions that aim to achieve specific changes in gait kinematics.
Investigation into Graph Signal Processing Applications to Muscle BOLD
Authors: Sooriyakumaran Thaejaesh , McGillivray Joshua , Noseworthy Michael
Published: August 2023

This investigation looks to use graph signal processing to generate a functional graph over the anatomical leg and assess the extracted functional information and its viability in modeling underlying physiological factors. The generated graph is constructed on the edge dimensions of node to node coherences and fractal dimension differences. The resultant graph structure is then analyzed to observe if extracted functional data shows alignment with underlying structures via a generalized linear mixed-effect mode
Comparison of pCASL, DSC and FAIR for Cerebral Perfusion in Rats @9.4T
Authors: Hung Lisa , Herrmann Karl-Heinz , Sibgatulin Renat , Hirschler Lydiane , Warnking Jan , Barbier Emmanuel , Witte Otto , Holthoff Knut , Reichenbach Jürgen , Joerk Alexander
Published: August 2023

Attaining reproducible, time-efficient, high spatial resolution and quantitative MRI perfusion images in small animal MRI @9.4T is still challenging. To take a step toward this goal, perfusion data from arterial spin labeling (ASL), Flow-sensitive Alternating Inversion Recovery (FAIR), dynamic susceptibility contrast (DSC), and pseudo-continuous arterial spin labeling (pCASL) sequences are compared by assessing cerebral perfusion in 5 rats, each scanned 3 times. Differences in (cerebral blood flow) CBF in major brain regions were analyzed, and the repeatability of perfusion MRI was assessed.
The impact of optimal RF coil-combination on whole-brain sub-millimetre resolution perfusion imaging at 7T
Authors: Kashyap Sriranga , Ivanov Dimo , Haast Roy , Fritz Francisco , Harms Robbert , Poser Benedikt , Uludag Kamil
Published: August 2023

In this work, we use 3D-EPI ASL to acquire perfusion maps of the human brain at an unprecedented spatial resolution of 0.7 mm isotropic at 7T. This multi-session, single-subject ASL dataset offers a unique opportunity to investigate the cortical distribution of baseline perfusion across and within brain areas, as well as studying the physiological basis for the interpretation of laminar and columnar fMRI. In this abstract, we use an open-source, memory-efficient, CPU/GPU accelerated coil-combine Python toolbox to probe the impact of using covariance-weighted sum-of-squares (CovSoS) and tSNR optimised RF coil-combination (STARC) on high-resolution perfusion imaging at 7T.
Predicting isocitrate dehydrogenase mutation status using contrastive learning and graph neural networks
Authors: Wei Yiran , Li Chao , Price Stephen
Published: August 2023

The isocitrate dehydrogenase (IDH) gene mutation status is a prognostic biomarker for gliomas. As an alternative approach to the invasive gold standard of IDH mutation detection, radiogenomics approaches using features of MRI showed promising results in the same task. Here, we proposed an approach to predict the IDH status based on the image and morphology features extracted using contrastive learning. We then constructed a large patient graph based on the extracted features, which could predict the IDH mutation using graph neural networks. The results showed the proposed method outperforms the classifiers which leverage either image or morphology features only.
Super Resolution of MR Images with Deep Learning Based k-space Interpolation
Authors: Arshad Madiha , Qureshi Mahmood , Inam Omair , Omer Hammad
Published: August 2023

Super resolution of MR images can be used to speed up MRI scan time. However, super resolution is a highly ill-posed problem as the low-resolution images lack high frequency spatial information. In this paper, we propose a hybrid dual domain cascaded U-Net to restore the high-resolution images. Firstly, the U-Net operating in k-space domain is used to interpolate the missing k-space data points and then the U-Net operating in image domain provides a refined high-resolution solution image. Experimental results show a successful reconstruction of high resolution images by using only central 6.25% and 25% k-space data.
Brain MRI acceleration with deep modular networks (BRACELET)
Authors: Mekhanik Anthony , Young Robert , Otazo Ricardo
Published: August 2023

Brain cancer screening utilizing MRI suffers from a bottleneck by requiring 3D acquisitions before and after contrast injection. We designed a novel two-stage deep learning reconstruction pipeline to accelerate 3D brain MRI over conventional 2-fold parallel imaging accelerations used in clinical practice. Using modular deep neural networks, we removed the dependence on one all-encompassing network. We successfully dealiased brain images at higher accelerations and with structural fidelity in lesions superior to conventional clinical imaging. Our method was validated on pathologies unseen during training using qualitative evaluation from an expert neuroradiologist and achieved comparable scores to conventional 2-fold clinical accelerations.
DL2: Robustness of Deep Learning Processing on Deep Learning reconstructed Lumbar Spine MRI
Authors: Hess Madeline , Bahroos Emma , Han Misung , Gao Kenneth , Pedoia Valentina , Majumdar Sharmila
Published: August 2023

We demonstrate that fast acquisition images reconstructed robust to segmentation with convolutional neural networks, which are known to generate chaotic errors in response to minimal image perturbations. This finding indicates that low-NEX images with DL-based noise reduction are not only robust to human readers, but machine readers as well.
129Xe MRI Binning Analysis using Reference Values: Age-dependent Changes in Gas-Exchange MRI
Authors: Willmering Matthew , Plummer Joseph , Walkup Laura , Cleveland Zackary , Woods Jason
Published: August 2023

Previous 129Xe-MRI binning analysis techniques assumed normal distributions or relied on a Box-Cox transformation. Adapting these binning methods to account for known covariates of lung function and structure, such as age and height, was not straightforward. To account for these limitations, a new binning method is proposed here that uses the same modeling techniques used to increase sensitivity and specificity in spirometry and diffusing capacity for carbon monoxide (DLCO). By accounting for MRI image distribution shapes and covariates, healthy representative data distributions are better modelled and can permit increased sensitivity and specificity, particularly for early cardiopulmonary disease progression.
Assessing the Age Dependence of 129Xe Gas-exchange MRI for Individual Healthy Subjects
Authors: Plummer Joseph , Willmering Matthew , Walkup Laura , Cleveland Zackary , Woods Jason
Published: August 2023

129Xe-MRI can quantify abnormal gas-exchange by defining thresholds derived from voxel-level gas-exchange distributions in healthy subjects. Previous studies assumed a constant healthy distribution independent of age. By fitting to Box-Cox Power Exponential distributions, normal distributions cannot be assumed, and the distributions vary significantly with age. The effect size of age (5-69 years) on healthy ventilation, barrier-uptake, and red-blood cell to barrier (ratio) signal distributions were 14 to 57%. Thus, age and distribution shape should be considered when defining reference distributions for gas-exchange metrics. By accounting for age-dependent variations, the reference distributions abnormal thresholds could be narrowed.
Texture Analysis as an Adjunct to Hyperpolarized 129Xe Ventilation Defect Percentage for Quantifying Cystic Fibrosis Lung Disease Severity
Authors: Basler Dustin , Bdaiwi Abdullah , Willmering Matthew , Walkup Laura , Cleveland Zackary , Woods Jason
Published: August 2023

MRI of hyperpolarized 129Xe has been shown to be a robust, non-invasive biomarker to assess pulmonary disease pathophysiology. Static spin-density maps (ventilation images) are commonly analyzed using the ventilation defect percentage (VDP) to quantify the degree of airway obstruction in diseases including asthma, chronic obstructive pulmonary disease, and cystic fibrosis. However, VDP reduces the intrinsic 3D-spatial richness of ventilation images to a global measure, suppressing underlying spatial correlations. In this work, a gray-level run-length matrix (GLRLM) analysis is assessed as an adjunct to VDP analysis for quantifying obstruction in Cystic Fibrosis (CF) lung disease, relative to a healthy control cohort.
Age and lung volume dependence of dissolved xenon-129 imaging parameters
Authors: Collier Guilhem , Chan Ho-Fung , Stewart Neil , Norquay Graham , Smith Laurie , Rao Madhwesha , Marshall Helen , Schulte Rolf , Wild Jim
Published: August 2023

This work investigates the correlation between age and pulmonary gas transfer measurements assessed with dissolved xenon-129 MRI in 26 healthy volunteers with an age range of 23 to 68yrs. Dependence on lung inflation is also investigated by performing imaging at total lung capacity. Results show significant negative correlations of xenon tissue uptake and blood transfer and suggest that an age-correction should be performed when reporting results. Imaging at total lung capacity also confirms a significant decrease in xenon gas transfer when compared to imaging during standard inspiratory breath-hold.
Intra-Visit and Inter-Visit Repeatability of 129Xe Multiple-Breath Washout MRI in Children with Stable Cystic Fibrosis Lung Disease
Authors: Alam Faiyza , Zanette Brandon , Braganza Sharon , Li Daniel , Ratjen Felix , Santyr Giles
Published: August 2023

Hyperpolarized 129Xe MRI (Xe-MRI) yielding VDP has shown advantages over conventional PFT’s for assessing paediatric CF lung disease but is only a static “snapshot” of a dynamic process. Xe-MRI can be conducted in a MBW fashion to yield temporal/spatial heterogeneity of the gas during respiration, resulting in regional maps of fractional ventilation (r), a measure of percent gas clearance per breath. This work assessed the within-visit and inter-visit repeatability of MBW Xe-MRI between baseline and one-month follow-up in paediatric subjects with stable CF and found strong intra- and inter-visit repeatability. Significant correlations between MBW Xe-MRI and LCI were also found.
Tumor oxygen levels and their response to hyperoxygenation in cancer patients measured using EPR oximetry with the OxyChip
Authors: Kuppusamy Periannan , Williams Benjamin , Chen Eunice , Kmiec Maciej , Schaner Philip
Published: August 2023

We report a first-in-humans clinical study of EPR oximetry using the OxyChip to establish its feasibility and utility for clinically useful tumor oxygen measurements in cancer patients. Repeated measurements from a cohort of 11 cancer patients in 33 sessions over a long period of time revealed variable levels of clinically significant hypoxia as well as variable responses to a hypoxia-mitigation intervention. Overall, in light of this variability, this study further underscores the need to provide individualized repeatable assessment of tumor oxygenation in the context of planned hyperoxygenation interventions to optimize clinical outcomes.