bluuebunny/crossref_metadata_2025 huggingface dataset:
1H spectroscopy of glutamate kinetics with 13C-glucose infusion in rodents at 7T
Authors: Kroenke Christopher , Zahr Natalie , Kittle Evan , Pfefferbaum Adolf
Published: August 2023

This work implements a method for measuring cerebral kinetics of glucose metabolism using 1H magnetic resonance spectroscopy (MRS) in rats using a small-animal 7T MRI system. The method has been demonstrated to be readily applied to nonhuman primates and human subjects using clinical MRI systems. The extension to small animals requires intravenous administration of small quantities of 13C-labeled glucose, and adaptation of data analysis procedures to data acquired at high magnetic field strength. We demonstrate robust quantification of 13C enrichment within the glutamate at the C4 position. This methodology will facilitate future translational research involving preclinical models of human disease.
Detection of GABA dynamics with edited functional MR spectroscopy at 3 Tesla: a comparison of modelling strategies
Authors: Beghini Laura , Saviola Francesca , Tambalo Stefano , Jovicich Jorge
Published: August 2023

There is increased interest in measuring brain GABA dynamics with MR spectroscopy, yet there is no consensus about robust and fast ways to do this. In this study, we evaluated how averaging affects GABA estimates when using different modelling strategies (Gannet, Osprey). Our results show that 60 MEGA-PRESS averages give valid concentration estimates, consistent with literature reports. Moreover, Gannet gives a GABA+/Cr measurement which should be more sensitive to concentration variations across regions and give lower temporal variability at rest relative to the GABA+/tCr measure in Osprey.
Differences in diffusion-weighted MRS processing and fitting pipelines, and their effect on tissue modeling: Results from a workshop challenge.
Authors: Najac Chloé , Döring André , Clarke William , Genovese Guglielmo , Just Nathalie , Kreis Roland , Lundell Henrik , Mosso Jessie , Mougel Eloïse , Oeltzschner Georg , Palombo Marco , Ligneul Clémence
Published: August 2023

A processing and fitting challenge was initiated for the “Best practices & Tools for Diffusion MR Spectroscopy” workshop held at the Lorentz Center (Leiden, NL) in September 2021. Our goal was to assess variabilities in processing and fitting pipelines and possibly identify the most robust steps to analyze diffusion-weighted MRS data. A “brain-like” dataset of diffusion-weighted spectra was simulated and participants were asked to analyze the data with their routinely used pipelines. Results showed that variabilities between participants (n=8) particularly increased at higher b-values and for J-coupled metabolites (Ins, Glu) as a result of lower SNR and higher CRLB values.
Uncertainties and bias in quantification by deep learning in magnetic resonance spectroscopy
Authors: Rizzo Rudy , Dziadosz Martyna , Kyathanahally Sreenath , Kreis Roland
Published: August 2023

Deep Learning has introduced the possibility to speed up quantitation in Magnetic Resonance Spectroscopy. However, questions arise about how to access and relate to prediction uncertainties. Distributions of predictions and Monte-Carlo dropout are here used to investigate data and model related uncertainties, exploiting ground truth knowledge (in-silico set up). It is confirmed that DL is a dataset-biased technique, showing higher uncertainties toward the edges of its training set. Surprisingly, metabolites present in high concentrations suffer from comparable high uncertainties as when present in low concentrations. Evaluating and respecting fitting uncertainties is equally crucial for DL and traditional approaches.
A meta-analysis of GABA and Glutamate response in functional magnetic resonance spectroscopy
Authors: Pasanta Duanghathai , Oeltzschner Georg , Ford Talitha , Lythgoe David , Puts Nicolaas
Published: August 2023

Functional magnetic resonance spectroscopy (fMRS) can be used to investigate the neurometabolic responses to external stimuli in-vivo, but findings to date are inconsistent. We performed a systematic review and meta-analysis on 49 human fMRS studies on Glutamate, Glx (Glutamate + Glutamine) and GABA. Small to moderate effect sizes of 0.29-0.47 (p < 0.05) were observed for Glu/Glx regardless of stimulus domain but not for GABA. Results suggest Glu/Glx and GABA responses vary with time course and are unique to stimulus domain or task. This analysis will inform study design in future work.
Investigation of metabolic changes in the hippocampus following spinal cord injury applying a metabolite-cycling semi-LASER technique
Authors: Zimmermann Sandra , Pfyffer Dario , Kreis Roland , Simsek Kadir , Freund Patrick , Seif Maryam
Published: August 2023

This work uses magnetic resonance spectroscopy data obtained in the hippocampus of 28 patients with traumatic spinal cord injury (SCI) to investigate SCI-induced metabolic changes. Structural magnetic resonance imaging was performed for hippocampal volumetric assessment. Eighteen healthy controls underwent the same imaging protocol. Study participants underwent a functional assessment by testing the visuospatial and verbal memory performance to check for cognitive impairments. In SCI patients without cognitive impairments, hippocampal metabolites did not differ from healthy controls. This study does not support evidence of degeneration and inflammation in the hippocampus of animal models of SCI that show impaired spatial memory performance.
Deep brain stimulation patient safety: Effects of patient-based lead trajectories on full-body 3 T MRI
Authors: Yang Benson , Arianpouya Maryam , Loh Aaron , Elias Gavin , Vetkas Artur , Sarica Can , Santyr Brendan , Graham Simon
Published: August 2023

High SAR RF pulse sequences continue to be avoided for patients with implanted deep brain stimulation (DBS) devices, due to the increased risk of injury. Recent studies have shown that DBS lead management can impact electromagnetic behavior and thus, the overall RF heating effects along the implanted device. The present work studied two patient-based DBS lead trajectories using a commercial DBS device with MR-conditional labeling for full-body 3 T MRI, implanted in a novel anthropomorphic phantom. The preliminary results showed temperature elevations that exceed current imaging guidelines remains possible for high SAR RF pulse sequences.
Significance of Covering Anatomical Variations for Conservative Assessment of Deposited Power of Leaded Implants in Patients
Authors: Kranold Lena , Goren Tolga , Rajan Sunder , Kuster Niels
Published: August 2023

Anthropomorphic computational phantoms are used to numerically estimate the potential envelope of intensity and distribution of induced E-fields in patients undergoing MR examination. The impact of anatomical variation of the phantom on medical implant risk assessment is demonstrated for generic transfer functions and lead trajectories representing pacemaker, DBS, SCS, and cochlear implant routings. Results showed that even when only one generic transfer function was considered, each of the 12 anatomical phantoms represented the worst-case for at least one configuration. Thus, the widest available range of anatomical phantoms must be examined to define a conservative safety envelope.
Implant heating in muscle-mimicking phantoms: an in silico evaluation of perfusion cooling
Authors: Louka Amgad , Bradfield-Handler William , Chronik Blaine
Published: August 2023

We have developed a novel perfusion phantom and this work describes the simulated RF-heating of a 10 cm titanium rod inside this phantom when placed inside the current gold standard (ASTM) phantom, and our geometry/muscle-mimicking phantoms. Simulations show a 30-45% decrease in observed heating due to perfusion cooling, and once these simulations are experimentally validated they could pave the way for improved acceptance criteria and ultimately improved patient access to MRI
Assessment of Femur Metallic Implant Safety at 3T
Authors: Trabelsi Amira , Benamara Megdouda , Jomin Pierre , Enoch Stefan , Dubois Marc , Pithioux Martine , Bendahan David , Abdeddaim Redha
Published: August 2023

We assessed electromagnetic behavior of metallic implant used for distal femur fracture in typical MRI situation. |B1+| field, SAR and temperature variations were computed at 3T using a surface coil on human model for different positions of the implant relative to the coil. To validate the simulation, we measured the E-field and compared it to simulated E-field. |B1+| field maps showed an interesting augmentation near the implant. Both global SAR and local SAR levels proved that it is possible to safely image bone repair. However, temperature elevation near the tip of the implant was important and is to be considerate.
Dependence of Electromagnetic Exposure on Design and Excitation Positions of 3T Two-Channel Whole-Body Birdcage Coils
Authors: Kozlov Mikhail , Kainz Wolfgang , Murbach Manuel
Published: August 2023

The safety assessment of RF exposure in MRI heavily relies on electromagnetic simulations. As there are numerous different coil designs on the market, this assessment is typically performed with sets of generic coil geometries to cover the commercially available bore diameter and coil lengths. This abstract investigated the effect of other design parameters, which are currently less considered. Our results show that feed-port positioning and non-ideal tuning of the coil may considerably alter the RF absorption pattern in an oval phantom, and even more so the E-field distribution outside the phantom.
BRAIN VOLUMES IN SICKLE CELL DISEASE ACROSS THE LIFESPAN: ALGORITHM PERFORMANCE AND CORRESPONDENCE WITH BLOOD OXYGEN CONTENT
Authors: Jones Randall , Donahue Manus , Waddle Spencer , Davis Larry , Pruthi Sumit , Lee Chelsea , Patel Niral , DeBaun Michael , Kassim Adetola , Rodeghier Mark , Jordan Lori
Published: August 2023

Brain tissue volumes were calculated in adults and children with sickle cell disease (SCD) across the lifespan for different segmentation algorithms and clinical indicators of disease. Tissue volume reductions in persons with SCD without prior stroke were detected when using FreeSurfer, but not other software, highlighting algorithm bias. Arterial oxygen content was directly related to tissue volumes when using FreeSurfer and SIENAX. Brain tissue volume was not associated with silent cerebral infarcts (SCIs). Findings highlight the subtlety of tissue volume changes in SCD, provide age-specific reference-standards, and motivate an integrated approach of anatomical and functional assessments for informing SCD care.
A clinical protocol for 3D imaging of the locus coeruleus with super-resolution at 3 Tesla
Authors: Rua Catarina , Symms Mark , Ghayoor Ali , Avants Brian , Bishop Courtney , Becerra Lino
Published: August 2023

The locus coeruleus (LC) is the principal source of noradrenaline production in humans. Histology studies have shown that severe loss of neurons in the LC is associated with many neurodegenerative disorders. Damage is thought to be non-uniform and occurring in stages, hence there is a growing interest in imaging the LC in vivo in these patient populations. In this work we propose a protocol for imaging the LC at clinical field strengths using a 3D magnetization-transfer prepared imaging sequence strategy and the application of super-resolution techniques to increase the LC features within the brainstem region.
A Novel GBM Infiltration Biomarker for Predicting Outcome: Clinical Study & Translational Preclinical Validation of ADC vs Tumor Cellularity
Authors: Vallatos Antoine , Al-Mubarak Haitham , Birch Joanna , Waldman Adam , Holmes William , Chalmers Anthony , Thompson Gerard
Published: August 2023

We report a novel clinical putative glioblastoma (GBM) biomarker of infiltration which predicts overall survival at presentation. Given the extreme challenges in obtaining comprehensive spatially matched MRI and tissue in humans to explore the biomarker biology, we assessed the relation between tumoral cellularity and ADC values in matched histology and MRI in a rodent infiltrating human xenograft GBM model. We demonstrate that the ADC slope measured along linear profiles perpendicular to the boundary of solid macroscopic tumor visible on ADC is a biomarker predictive of overall survival in a single centre human cohort. We demonstrate a strong correlation between ADC and tumor cellularity in the preclinical model, supporting the hypothesis that a radial vectorial profile analysis of tumor ADC maps could provide with a robust clinical biomarker of glioblastoma cell infiltration and therefore outcome.
Influence of Arterial Transit Time Delay in Arterial Spin Labeling on Differentiating Tumor Progression and Pseudo-Progression in Glioblastoma
Authors: van Dorth Daniëlle , Jiang Janey , Schmitz-Abecassis Bárbara , Croese Robert , Taphoorn Martin , Smits Marion , Koekkoek Johan , Dirven Linda , de Bresser Jeroen , van Osch Matthias
Published: August 2023

In the clinical follow-up of glioblastoma patients, presence of delayed arterial transit times (ATT) could affect the evaluation of ASL perfusion data. In this retrospective study the influence of the presence and severity of ATT-artifacts on perfusion assessment and differentiation between tumor progression and pseudo-progression were studied. The results show that the presence of ATT-artifacts lowers the agreement between radiological evaluation of DSC-MRI and ASL, although the severity of ATT-artifacts did not have significant influence. In conclusion, detection of ATT-artifacts is important as it could affect radiological evaluation of ASL-data. Future work aims to include additional quantitative perfusion measures.
IDH mutation prediction in glioma patients using 7T 3D-FID-MRSI
Authors: Sharma Sukrit , Cadrien Cornelius , Lazen Philipp , Furtner Julia , Licandro Roxane , Lipkal Alexandra , Heckova Eva , Hingerl Lukas , Motyka Stanislav , Gruber Stephan , Strasser Bernhard , Kiesel Barbara , Mischkulnig Mario , Preusser Matthias , Roetzer-Pejrimovsky Thomas , Wöhrer Adelheid , Weber Michael , Dorfer Christian , Rössler Karl , Trattnig Siegfried , Bogner Wolfgang , Widhalm Georg , Hangel Gilbert
Published: August 2023

We used brain MRSI to explore the differentiation of gliomas regarding IDH-1 and Wildtype mutation. We found significant differencesin metabolites like Gln/NAA, Ins/NAA, and GPC+PCh/NAA using the Mann-Whitney-Wilcoxon test. More metabolites with signifi-cant differentiation were used for IDH classification using Random Forest, which also showed better classification results with additionalmetabolites than GPC+PCh/NAA alone. The ROC curve with more than GPC+PCh/NAA as feature yields an AUC value of 81 %.
Tumor microvasculature and microenvironment characterization in mouse models of pancreatic ductal adenocarcinoma using multiparametric MRI
Authors: Paudyal Ramesh , Russell James , Wolansky Ivan , LoCastro Eve , Lekaye Carl , Deasy Joseph , Humm John , Shukla-Dave Amita
Published: August 2023

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second cause of cancer-related deaths worldwide. Quantitative multiparametric magnetic resonance imaging (mpMRI) provides the complementary physiological properties of tumors tissue. The aim of this study was to characterize microvasculature and microenvironment in mouse models of PDAC using mpMRI. The functional status of mpMRI quantitative imaging metrics were validated with in vivo histology markers of tumor perfusion (Hoechst 33342) and tissue morphology (Hematoxylin and eosin staining).
Probing Cerebello-Cerebral Functional Connectivity in Spinocerebellar Ataxias
Authors: Anteraper Sheeba , Zhang Ying , Guell Xavier , Povazan Michal , Banan Guita , Valabregue Romain , Ehses Philip , Faber Jennifer , Joers James , Onyike Chiadi , Barker Peter , Schmahmann Jeremy , Ratai Eva-Maria , Subramony S , Mareci Thomas , Bushara Khalaf , Durr Alexandra , Klockgether Thomas , Ashizawa Tetsuo , Lenglet Christophe , Öz Gülin
Published: August 2023

Spinocerebellar Ataxias (SCAs) are a group of rare, autosomal dominant diseases that result in progressive degeneration of the cerebellum. Of these, SCA1 is the fastest progressing. SCA3, the most prevalent SCA worldwide, is relentlessly progressive, disabling, and eventually fatal with no efficacious treatments other than supportive therapy. There is a strong need to improve our mechanistic understanding of the changes in the cerebello-cerebral circuitry prior to disease manifestation so that novel therapeutic strategies can be developed. Analyzing high quality magnetic resonance imaging data from the NIH-funded project, “Clinical Trial Readiness for SCA1 and SCA3 (READISCA),” will guide such efforts.
Compartment-Specific Metabolic Investigation of 3D Cell Culture by Real-time NMR for Investigating Metabolic Diseases
Authors: Urzi Christian , Hertig Damian , Meyer Christoph , Nuoffer Jean-Marc , Vermathen Peter
Published: August 2023

In this study was shown the possibility to perform compartment-specific metabolic investigations of living fibroblasts in real-time using a bioreactor system within an NMR spectrometer. Cell volume and the ratio cells to extracellular medium within the sensitive region of NMR coil were evaluated for quantification purposes. The needed sensitivity to detect metabolite changes in the extracellular footprint at different flow rates was shown. The capability of diffusion technique to distinguish between compartment-specific contributions was revealed, and to detect changes in compartment-specific metabolite pools under standard or selective culture conditions, and upon inhibitor challenges.
Demonstration of an end-to-end open-source pipeline for a spiral-based rs-fMRI sequence
Authors: Jimeno Marina Manso , Vaughan John , Geethanath Sairam
Published: August 2023

Spiral trajectories are suitable for fMRI as they provide high temporal resolution and motion tolerance. However, they are not typically available on scanners as the associated reconstruction is more involved. We have demonstrated the feasibility of an open-source spiral sequence end-to-end pipeline and compared it to the vendor-supplied EPI sequence. Although the spiral images showed signal loss near the frontal sinus, both datasets presented similar image quality and contrast. Importantly, the spiral sequence had a 2.3-fold advantage on temporal SNR and achieved analogous functional connectivity maps of the DMN, demonstrating the sequence BOLD sensitivity and viability.
Open Science Initiative for Perfusion Imaging (OSIPI): A community-led, open-source code library for analysis of DCE/DSC-MRI
Authors: van Houdt Petra , Ragunathan Sudarshan , Berks Michael , Ahmed Zaki , Kershaw Lucy , Gurney-Champion Oliver , Tadimalla Sirisha , Kallehauge Jesper , Arvidsson Jonathan , Dickie Ben , Lévy Simon , Bell Laura , Sourbron Steven , Thrippleton Michael
Published: August 2023

A lack of validated, open-source code reduces the reliability of perfusion MRI, resulting in duplicate development. To address this problem, the Open Science Initiative for Perfusion Imaging (OSIPI) established a taskforce to collect, validate and harmonise such code. To date, 74 code contributions have been collected, with 14 of these tested. Source code and tests are published in an open-access repository. The OSIPI DCE/DSC-MRI code collection constitutes a valuable resource for researchers, and will ultimately be developed into a standardised, community-driven open-source code library.
Visualising and interacting with diffusion MRI microstructural models using FSL-DIVE
Authors: Cottaar Michiel , Eichert Nicole , Rafipoor Hossein , Howard Amy , Kor Daniel , Kang Jiewon , Chaggar Pavan , Zheng Ying-Qiu , Fitzgibbon Sean , Jbabdi Saad
Published: August 2023

We introduce FSL-DIVE, an interactive visualisation software for diffusion microstructure modelling. This software allows the user to (i) flexibly set up a multi-compartment microstructure model, including fibre orientation modelling and restricted diffusion, (ii) choose different acquisition parameters, (iii) change the model parameters and analyse the model behaviour through multiple bespoke plots, (iv) save the predicted data (including noise) for any specified acquisition scheme. We hope this tool may be useful for teaching diffusion microstructure modelling, for developing new models, or for getting a better understanding of existing models.
Spin-Lock Times selection for Optimized T1ρ-Mapping of Knee Cartilage on Bi-Exponential and Stretched-Exponential Models
Authors: de Moura Hector Lise , Zibetti Marcelo Wust , Regatte Ravinder
Published: August 2023

T1ρ-Mapping requires acquisition with multiple Spin-Lock Times (TSLs) in order to fit the free parameters of the model. Reducing the #TSLs poses a trade-off between acquisition time and estimation error. Also, the choice of TSLs has a significant influence on the fitting results. A previous study analyzed the Cramér-Rao Lower Bound (CRLB) as an optimization criterium for the TSL choices using different #TSLs for Mono-Exponential models. This study extends the use of CRLB for Stretched- and Bi-exponential models using complex-valued fitting via Non-linear Least Squares. Experiments show that optimized TSL sequences improve parameter estimation when compared to non-optimized TSL sequences.
MAGiC in glioma: Are pre-contrast quantitative MRI parameters different in tumors with versus without enhancement?
Authors: Nunez-Gonzalez Laura , van Garderen Karin A. , Smits Marion , Jaspers Jaap , Romero Alejandra Méndez , Poot Dirk H. J. , Hernandez-Tamames Juan A.
Published: August 2023

We analyze quantitative values in glioma obtained with MAGiC, which allows obtaining quantitative T1, T2 and PD maps in one single acquisition of less than 6 minutes for a whole brain. The maps were obtained before contrast-agent injection in 14 patients with glioma. We investigated the possibility of characterizing tumor regions based on quantitative maps acquired without contrast-agent. The results showed significant differences among tumoral tissue, tissue with T1w-enhancement, and normal white matter. Voxel-wise, this allowed to distinguish tumoral tissue but did not allow to accurately predicting T1w-enhancement. However, promising results were found predicting T1w-enhancement inside the tumor.
On the Prospects of Magnetization Transfer Imaging at 0.55T
Authors: Afshari Roya , Bauman Grzegorz , Bieri Oliver
Published: August 2023

Magnetization transfer (MT) imaging has been extensively used to explore microstructural changes in the brain at high fields. In this work, we explore the potential of a 3D half-radial dual-echo balanced steady-state free precession (bSSFP) sequence for fast whole-brain magnetization transfer ratio (MTR) imaging at low-field strength. Our work indicates superiority of MT-sensitized bSSFP against conventional MT-prepared spoiled gradient echo (SPGR) in terms of MT contrast and resolution within similar scan time. In conclusion, MTR imaging with bSSFP offers excellent prospects for broad clinical translation and application at low fields.
Simultaneous Mapping of B0, B1 and T1 Using a CEST-like Pulse Sequence and Neural Network Analysis
Authors: Schuenke Patrick , Heinecke Kerstin , Narvaez George , Zaiss Moritz , Kolbitsch Christoph
Published: August 2023

Obtaining isolated effects in Chemical Exchange Saturation Transfer (CEST) MRI requires the correction for the influence of B0- and B1-inhomogeneities and the T1 relaxation time during post-processing. We present an extended approach for simultaneous mapping of B0, B1 and T1 using a CEST-like pulse sequence and a regularized neural network-based analysis that provides additional uncertainty estimations. We demonstrate the in vitro and in vivo applicability of the proposed approach, which is trained using simulated data and confirm its accordance with established reference methods.
Deep learning-based motion correction for Semisolid MT and CEST imaging
Authors: Singh Munendra , Moghadas Babak , Jiang Shanshan , van Zijl Peter , Zhou Jinyuan , Heo Hye-Young
Published: August 2023

Conventional semisolid magnetization transfer contrast (MTC) and chemical exchange saturation transfer (CEST) MRI studies typically employ acquisition of a series of images at multiple RF saturation frequencies. Furthermore, quantitative MTC and CEST imaging techniques based on MR fingerprinting (MRF) require a range of values for multiple RF saturation parameters (e.g. B1, saturation time). These multiple saturation acquisitions lead to a long scan time, which is likely vulnerable to motion during in vivo imaging. Motion correction is hard due to varying image intensity between acquisitions. Herein, we proposed a deep learning-based motion correction technique for conventional Z-spectra and MRF data.
Heroin addiction and relapse-induced axonal transport impairment in the brain and detected by in vivo MRI
Authors: Luo Yueyuan , Yang Jun , Liao Chengde , Zhang Zhongping
Published: August 2023

Heroin plays role in heroin-induced cognitive dysfunction is unclear. We used manganese-enhanced magnetic resonance imaging for to evaluate the effect of heroin on axon transport in the body.
Machine Learning based Differentiation of Non-Enhancing Tumor from Vasogenic Edema in patients with Low Grade Gliomas using DCE-MRI
Authors: Yadav Virendra , Gupta Rakesh , Agarwal Sumeet , Singh Anup
Published: August 2023

Precise safe surgical resection and precisely directed radiation are important in clinical practice for low-grade gliomas (LGGs) patients in order to minimize the neurological deficit and radiation toxicity, respectively. Clinicians find difficulty in defining the border between the non-enhancing tumor and edema components. In this study, machine learning-based models were developed in order to distinguish non-enhancing tumors from vasogenic edema using quantitative perfusion parameters obtained using dynamic-contrast-enhanced MRI. The proposed approach may help in assisting radiologists, by defining precise tumor boundaries and hence, results in improving patients’ quality of life and overall survival.
A Cloud-based MR Spectroscopy Tool for Basis Set Simulation
Authors: Hui Steve , Saleh Muhammad , Zöllner Helge , Oeltzschner Georg , Fan Hongli , Li Yue , Song Yulu , Jiang Hangyi , Near Jamie , Mori Susumu , Lu Hanzhang , Edden Richard
Published: August 2023

MRSCloud is an online-based spectral simulation tool for brain metabolites. Up to 32 metabolites can be simulated to generate a basis set for linear combination modeling. The 1D projection method, coherence pathway filters and pre-calculation of propagators have been implemented for density-matrix simulations to run on a high-performance cloud server. Results indicated simulations were comparable with FID-A and difference between simulations of spatial points (21x21/41x41/101x101) were small. It allows community users to generate vendor, sequence, editing experimental-specific basis sets that are appropriate for their studies.
Mechanical Resonance Recording and Analysis using auDIO files (MR-RADIO)
Authors: Dillinger Hannes , Peper Eva , Guenthner Christian , Kozerke Sebastian
Published: August 2023

This work presents a web-based framework for the identification of mechanical resonances of MRI gradients systems based exclusively on mobile phone audio recordings. frequencies are used to guide beneficial combinations of TE/TR for PC-MRI and readout bandwidth settings for EPI sequences. Results demonstrate that the background phase in PC-MRI as well as beat phenomena during EPI readouts can be reduced. The web app can be found at https://mr-radio.herokuapp.com and its source code is publicly available at https://github.com/hdillinger/mr-radio in the spirit of reproducible research.
PySynthMRI: An open-source Python tool for Synthetic MRI
Authors: Peretti Luca , Cencini Matteo , Cecchi Paolo , Donatelli Graziella , Costagli Mauro , Tosetti Michela
Published: August 2023

Synthetic MR imaging allows reconstruction of different image contrasts from a single acquisition, reducing scan times. Here we introduce PySynthMRI, an open-source tool which provides a user-friendly and fluid interface to synthesize and modify contrast-weighted images. The tool allows the user to add and adjust virtual scanner parameters showing, in real time, how the resulting synthesized images vary accordingly, which makes PySynthMRI a valuable tool for both research and teaching. The generated images can be exported in the preferred format.
Molecular imaging of breast cancer by chemical exchange saturation transfer (CEST) MRI of glucosamine: first human experience
Authors: Rivlin Michal , Anaby Debbie , Nissan Noam , Zaiss Moritz , Deshmane Anagha , Sklair-Levy Miri , Navon Gil
Published: August 2023

In preclinical experiments in implanted breast cancer tumors in mice, glucosamine (GlcN) exhibited enhanced chemical exchange saturation transfer (CEST) MRI signals. Moving toward clinical application, considering the excellent safety profile of GlcN, we examined the feasibility of using the GlcN CEST method to detect human breast cancer on a 3T clinical scanner. Here we report significant CEST MRI signals resulting from the exchangeable protons of GlcN hydroxyls, amine/amide residues as well as nuclear Overhauser enhancement (NOE). Thus, CEST MRI using GlcN has the potential to detect tumors and report their activity, without the use of a gadolinium contrast agent.
Presaturation pulse shape enables shifting the pH sensitivity of guanidyl CEST-MRI for absolute pH mapping at 9.4 T
Authors: Boyd Philip , Diederichs Lilli , Breitling Johannes , Ladd Mark , Bachert Peter , Goerke Steffen
Published: August 2023

In this study, we present a method for absolute pH mapping using the guanidyl CEST signal. The method is an extension of a previous approach that allowed compensating for various concomitant effects other than pH, but additionally required measuring the amide signal. By optimizing the pulse shape of the pulsed presaturation the pH sensitivity of the guanidyl signal could now be shifted to the physiologically relevant range around pH 7.1. The shift of sensitivity was verified experimentally in a multi-pH creatine phantom at 9.4T. Thus, CEST-based pH mapping with exceptional specificity is now also possible using only the guanidyl signal.
Cardiac motion modeling using DENSE imaging to study cardiac diffusion tensor MRI
Authors: Moulin Kevin , Rahman Tanjib , Viallon Magalie , Croisille Pierre , Perotti Luigi
Published: August 2023

Cardiac Diffusion Tensor imaging (cDTI) is a powerful non-contrast technique that can characterize cellular structure in vivo. Despite motion-compensated diffusion encoding designs, cDTI remains sensitive to unwanted cardiac motion, particularly during diastole. The lack of knowledge of the detailed interaction between real cardiac motion and motion-compensated gradients prevents more advanced diffusion encoding designs. The objective of this work is to provide a new simulation framework to study the interaction between cardiac displacements estimated in vivo from DENSE imaging and motion-compensated diffusion encoding waveforms.
Acceleration Methods to Acquire Fast 3D Multi-Channel Absolute B1+ Maps at 7T for 8-Channel pTx
Authors: Kent James , Valkovic Ladislav , Dragonu Iulius , Hess Aaron
Published: August 2023

Ultra-high field MRI with parallel transmit offers significant advantages but B1 transmit maps must be acquired to utilize its full potential. Acquiring absolute B1+ maps for each channel is a time-consuming process and limits the application of UHF to clinical practice. We compare two methods of accelerating the transmit mapping procedure to obtain fast volumetric multi-channel maps for an 8-channel transmit array. Both methods make use of a low-rank reconstruction (TxLR) from undersampled data and a modified pre-saturation TurboFLASH (satTFL) B1+ mapping sequence in combination with either Fourier encoding or a B1TIAMO style acquisition.
Motion-Dependent Low-Order Predictive Linear Model for Patient Safety Assessment at 7T with Technically Feasible Coil Models
Authors: Ajanovic Amer , Brackenier Yannick , Tomi-Tricot Raphael , Hajnal Joseph , Malik Shaihan
Published: August 2023

Establishing a comprehensive model that addresses patient safety at UHF MRI with respect to motion is a non-trivial task because of the underlying computationally expensive frameworks. Using MARIE we computed a large number of pose simulations of 3 feasible coil models (birdcage, 4-channel and 8-channel pTx) in proximity to Duke body model to allow the parameter space to be well explored. It is found that a low order linear model can capture most of the variation in cpB1+. We also observe low variations in cpSAR for 2 realistic coil models across the conditions examined, with 8-channel coil being most robust.
Calibration-free parallel transmission for improved CSF mobility imaging at 7T
Authors: Ehses Philipp , Hirschler Lydiane , Pracht Eberhard , Deike-Hofmann Katerina , Gras Vincent , Mauconduit Franck , Massire Aurélien , Boulant Nicolas , van Osch Matthias , Stoecker Tony
Published: August 2023

Better understanding of how the brain cleans itself is of high importance as its failure has been linked to various neurodegenerative diseases. A first step towards elucidating CSF-mediated clearance mechanisms is the measurement of CSF motion in the human brain. In this work, we present an imaging sequence for CSF mobility measurements employing calibration-free parallel transmission. During the imaging session, no pulse calculations or complex B1 shimming procedures are necessary, making this approach feasible for large scale patient studies.
Acute Global Structural and Diffusivity Changes Following Treatment with MRgFUS
Authors: Kyle Kain , Barnett Yael , Tisch Stephen , Jonker Ben , D'Souza Arkiev , Maller Jerome , Barnett Michael , Maamary Joel , Wang Chenyu
Published: August 2023

MRgFUS is a non-invasive procedure for the treatment of tremor, involving the application of high-energy ultrasound waves to ablate tissue in the brain in regions implicated in tremor networks. There is a lack of data on the acute changes outside the ablated region following treatment with MRgFUS. This investigation sought to examine changes in brain volume and diffusion tensor metrics following treatment with MRgFUS.
Associations between DCE-MRI parameters and MVD, VEGF and HIF-1α in osteosarcoma based on MRI-histopathological comparison
Authors: Ma Huan , Wang Yao , Li Kun , Ding Yingying , Li Jialu , Zhang Xiaoyong
Published: August 2023

Tumor necrosis, angiogenesis and hypoxia are related to therapeutic effect, aggressiveness, metastasis and prognosis for osteosarcoma. In this study, DCE-MRI were matched ROI-to-ROI with histopathological tissues to explore the relationship between the perfusion parameters, including Ktrans, Kep, and Ve in each ROI and TNR, MVD, VEGF and HIF-1α in corresponding histopathological specimens, aiming to offer information about angiogenesis and hypoxia in the microenvironment of osteosarcoma timely and non-invasively. We found the perfusion parameters of DCE-MRI have a moderate sensitivity and specificity to evaluate MVD, VEGF and HIF-1α in the histopathological tissues of osteosarcoma, thereby helping microvessel status and hypoxia evaluating.
Three IVIM-DWI models to predict survival risk in laryngeal and hypopharyngeal squamous cell carcinoma patients after (chemo)radiotherapy
Authors: Zhang Ya , Luo Dehong , Guo Wei , Liu Zhou , Bao Dan , Xu Haijun , Li Lin , Lin Meng , Zhao Yanfeng , Zhao Xinming
Published: August 2023

To investigate the predicted survival risk power of three IVIM-DWI models in laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC) patients after (chemo)radiotherapy, 45 patients were retrospectively enrolled. IVIM-DWI sequence scanning was performed using echo planner imaging (EPI) sequence with 12 b values (0, 10, 20, 30, 50, 70, 100, 150, 200, 400, 800 and 1000 s/mm2). Followed up for 2-72 months with median follow-up of 14 months. The pretreatment ADC, D, f value and D* value were significantly correlated with prognosis of local disease, and the pretreatment ADC, D* value were independent biomarkers for survival risk prediction.
Investigating the influences of spectral lineshape and linewidth in LCModel basis-sets on 1H MRS quantification at 7T
Authors: Xiao Ying , Tkáč Ivan , Xin Lijing
Published: August 2023

In this study, we investigated the 1H MR spectra quantification accuracy using basis sets with different linewidths and lineshapes in LCModel. Simulation results showed that the estimated metabolite concentrations depend on the linewidths and lineshapes of the basis sets as well as the spectral lineshape. This effect was validated with in vivo MR results. We conclude that the spectral lineshape and linewidth of basis sets should be carefully considered for accurate metabolite concentration estimations from short-TE 1H MR spectra using LCModel.
Improved MP-PCA denoising through tensor generalization
Authors: Olesen Jonas , Ianus Andrada , Shemesh Noam , Jespersen Sune
Published: August 2023

A popular SNR-boosting method in MRI is denoising based on principal component analysis with automated rank estimation by exploiting the Marchenko-Pastur distribution of noise singular values (MP-PCA). MP-PCA operates by reshaping data-patches into matrices to discriminate signal from noise using random matrix theory. Here, we generalize MP-PCA to exploit tensor-structured data arising in, e.g., multi-contrast or multicoil acquisitions, without introducing new assumptions. As proof of concept, we demonstrate a substantial increase in denoising performance in a multi-TE DKI dataset, in particular for small sliding windows. This is beneficial especially in cases of rapidly varying contrast or spatially varying noise.
Comparison of intra-voxel spatial distributions of diffusion coefficients with intra-voxel spatial distributions of kurtosis coefficients
Authors: Yokosawa Suguru , Shirai Toru , Bito Yoshitaka , Ochi Hisaaki
Published: August 2023

Previously, we have proposed the method for characterizing the intra-voxel spatial distribution of apparent diffusion coefficients (ADC) by using texture analysis and showed that texture features can provide different information from the conventional diffusion tensor imaging. In this study, we extended our method to the apparent kurtosis coefficients (AKC). We compared the features of the intra-voxel spatial distribution of ADC with that of AKC. We found that there is no significant difference in the spatial distribution of AKC from that of ADC, and a short scanning time with a single b-value may be sufficient to obtain information on diffusion distribution.
Comparison and validation of multiple MR-EPT methods with ground truth vector network analyzer measurements
Authors: He Zhongzheng , Doguet Martin , Soullié Paul , de Sousa Paulo Loureiro , Lefebvre Pauline , Odille Freddy
Published: August 2023

Many MR-EPT reconstruction methods have been published, however, there is a lack of comparative experiments to verify the reconstructed electrical properties (EP) maps. In this work, we compared and validated the phase-based (PB), complex-image-based (CIB), and their simplified methods with ground truth vector network analyzer measurements on different conductivity phantoms. After serval comparative experiment repetitions, the complex-image-based method by Soullié et al.[1] was the most consistent to the VNA ground truth measurements. The proposed setup can be used to compare other MR-EPT reconstruction methods.
Deep prior for suppressing noise amplification and edge preservation in Phase-based EPT with Low-SNR image
Authors: Cui Chuanjiang , Kim Jun-Hyeong , Jung Kyu-Jin , Yi Jaeuk , Kim Dong-Hyun
Published: August 2023

Phase-based EPT algorithm is extremely sensitive to noise. Although many studies have investigated such as linear(Gaussian filter) or non-linear filter(TV norm) to cope with amplification, textured noise and staircasing effect still remain in phase image, which lead to conductivity error such as broadening boundary artifact or high std value in reconstructed conductivity maps. In this study, we propose a deep prior based denoising method, which achieve to not only suppress instability brought by noise amplification but reduce boundary error.
Design of Novel RF Pulse for Fetal MRI Refocusing Trains using Rank Factorization (SLfRank) to Reduce SAR and Improve Image Acquisition Efficiency
Authors: Diaz Sebastian , Arefeen Yamin , Gagoski Borjan , Grant Ellen , Adalsteinsson Elfar
Published: August 2023

Fetal MRI is inherently time-constrained due to unpredictable motion and comfort concerns. Single-shot spin-echo sequences address these concerns by rapidly acquiring images with desired tissue contrast. However, these sequences typically operate at specific absorption rate (SAR) limitations due to a train of refocusing pulses, which impose long TR times and reduce acquisition efficiency. This study leverages SLfRank, the use of ranked factorization to jointly solve for SLR bi-coupled spin parameters, to design refocusing profiles that reduce SAR while maintaining slice-profile performance. The proposed refocusing pulse reduced SAR by over 20% while producing similar image quality to the standard clinical sequence.
Optimal control pulse design as a low power alternative to BIR4 excitation pulses
Authors: Somai Vencel , Wright Alan , Chia Ming Li , Brindle Kevin
Published: August 2023

The BIR4 pulse achieves adiabatic excitation over a moderate frequency range but has a relatively high adiabatic threshold, which is demanding on the hardware and deposits significant energy when the repetition rate is high. We show here using simulations and an experiment in vivo that optimal control can provide a better alternative with a significantly lowered adiabatic threshold.
Simultaneous Multi Slice using Hadamard like encoding with non-Hadamard factors
Authors: Ramanna Sudhir , Agarwal Harsh , Sundaresan Rajagopalan , Rajamani Sajith , Reddy Ashokkumar , Mehta Bhairav , Venkatesan Ramesh
Published: August 2023

Multiplexing of slices using the NEX/averaging dimension is an option for clinical MR protocols to improve SNR without imposing a scan time penalty. Hadamard encoding and decoding imposes Hadamard factors as limits where in only powers of 2 is used. We propose to use a Hadamard like encoding scheme but decode differently to yield a reduced effective NEX and improved motion sensitivity. This enables us to use any integer multiband factors.
B1-Compensating RF Excitation for Imaging hyperpolarized 13C nuclei with bSSFP using a 13C Cryo-Coil
Authors: Nagel Luca , Topping Geoffrey , Schilling Franz
Published: August 2023

Cryogenically cooled transmit/receive RF surface coils (cryocoils) can improve signal-to-noise ratio (SNR) up to 4X1. With flat profile RF pulses, surface coil excitation profiles are highly inhomogeneous, complicating the use of most pulse sequences, and especially the fast and efficient bSSFP sequence. A transmit B1-compensating RF pulse that produces uniform excitation with a Tx/Rx 13C cryo-coil was developed and tested in 3D-FLASH and 3D-bSSFP. Thermal 13C phantom imaging showed a regional uniform excitation, and proof-of-concept time-resolved 3D bSSFP imaging of hyperpolarized [13C]urea was demonstrated in mice.
Assessment of age-related changes of oxygen extraction fraction in of normal adults using QSM and quantitative BOLD
Authors: Wang Jieyu , Cho Junghun , Zhang Chen , Wang Yi , Yu Bing
Published: August 2023

With aging, the brain undergoes comprehensive changes in its function and physiology, including oxygen consumption metabolism. In this study of healthy aging from 24-69, oxygen extraction fraction (OEF) mapping was generated using QSM and quantitative BOLD (QSM+qBOLD, QQ) processing of challenge-free 3D multi-echo gradient echo (mGRE). OEF values were found to increase with age only in specific gray matter brain regions (mainly in SomMot and SalVentAttn functional networks) and to decrease with age only in specific white matter brain regions (mainly Callosum ,cingulate,superior frontal blade).
Subcortical Gray Matter Nucleus Lateralization of Amide Proton Transfer Weighted Signals in Young Healthy Subjects
Authors: Jiang Yuhan , Liu Yangyingqiu , Gao Bingbing , Song Qingwei , Miao Yanwei
Published: August 2023

Amide proton transfer weighted (APTw) imaging is a novel molecular imaging technique to acquire the proton exchanged signals from the amide in proteins or peptides to water. Previous studies discovered lateralization in the brain structure and function, including the subcortical gray matter nucleus. However, it is not clear whether APTw also has lateral advantage. In this study, we applied the automatic brain segmentation method to quantify the APTw signal values of subcortical gray matter nucleus in young healthy subjects. The increased APTw signals were present in the right side of the subcortical gray matter nucleus，which may suppose related with right-handedness.
Distinct patterns of tremor network microstructure for essential tremor and Parkinson’s disease
Authors: Welton Thomas , Ong Amadis , Hartono Septian , Shih Yao-Chia , Lee Amanda , Tan Eng-King , Chan Ling Ling
Published: August 2023

Differential diagnosis of essential tremor and Parkinson’s disease can be challenging due to overlapping clinical presentations, but these diseases differ in neuropathological features, which may be detected using diffusion spectrum imaging. We identified parts of a tremor-related cerebello-thalamo-cortical network based on diffusion spectrum imaging that differed among a cohort comprising essential tremor and Parkinson’s patients, and healthy-controls. The patient groups had minimally-overlapping areas of abnormal microstructure in the tremor-network, and these were significantly correlated with clinical and kinetic measures of tremor severity. A future DSI-based marker of tremor-network microstructure may aid in differential diagnosis of essential tremor and Parkinson’s disease.
Gray and white matter alterations in different predominant side and type of motor symptom in Parkinson’ disease
Authors: Chen Jingwen , Zhou Cheng , Wu Jingjing , Guo Tao , Bai Xueqin , Wu Haoting , Liu Xiaocao , Wen Jiaqi , Cao Zhengye , Zhang Yong , Guan Xiaojun , Xu Xiaojun , Zhang Minming
Published: August 2023

It has been overlooked in clinical that there exists a complex relationship between laterality and motor symptoms in Parkinson’s disease (PD) and these factors may influence their motor and nonmotor symptoms in together. Here we found PD with left-side akinetic/rigid (L-AR) signs performed worst in clinical manifestations. And the underlying brain structure alterations was revealed severer damage in anterior cingulate and its connected fibers of right hemisphere by a multimodal imaging approach including cortical thickness and diffusion-weighted MRI measures.
Multimodal imaging signatures of the epileptogenic zone
Authors: Huang Hui , Yuan Siyu , Zhang Miao , Liu Wei , Zhao Yibo , Guo Rong , Li Yudu , Tang Lihong , Liang Zhi-Pei , Li Yao , Luo Jie
Published: August 2023

Accurate detection of the epileptogenic zone for surgical planning often relies on stereo-electroencephalography, which is limited by low spatial sampling. Development of noninvasive brain high resolution imaging to better identify epileptogenic zone is of great value. This study aimed to investigate the imaging signature for detection of epileptogenic zones among features extracted from structural, functional, and metabolic imaging using hybrid PET/MR scanner. Our results highlighted the value of combination between metabolic and functional imaging features.
WM integrity of right AF in predicting language recovery of chronic poststroke aphasia after LF-rTMS treatment
Authors: Lin Bing-Fong , Hon Fei , Tsai Po-Yi , Lu Chia-Feng
Published: August 2023

Low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) provided promising results to facilitate the language recovery in stroke patients with non-fluent aphasia 1. The contralesional inhibitory LF-rTMS treatment can induce the functional reorganization within language networks and recovery of language function in chronic aphasic stroke 2, 3. This study evaluated the right microstructural integrity of the arcuate fasciculus before the intervention and its association with the language improvement after the LF-rTMS treatment.