bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of diffusion MRI-derived white matter microstructure metrics using 3D electron microscopy in injured rat brain
Authors: Coronado-Leija Ricardo , Abdollahzadeh Ali , Lee Hong-Hsi , Coelho Santiago , Salo Raimo , Tohka Jussi , Sierra Alejandra , Novikov Dmitry , Fieremans Els
Published: August 2023

To validate the standard model of diffusion in white matter, we characterized injured rat brain microstructure using 3D EM and ex-vivo MRI. Using histology, we demonstrated that the rotational invariants $$$p_l$$$ of the fiber orientation distribution follow a power-law and that the axon diameter histogram is described well by a generalized extreme value distribution. Comparing 3D EM and dMRI, we found that the SM parameters correlate specifically with their histology counterpart, and revealed the specificity of the intra-axonal diffusivity to axonal beading in traumatic brain injury.
Accelerating IVIM and DTI for assessing microstructural changes after acute hamstring injury
Authors: Rauh Susanne , Monte Jithsa , Hooijmans Melissa , Suskens Joep , Gurney-Champion Oliver , Tol Johannes , Maas Mario , Nederveen Aart , Strijkers Gustav
Published: August 2023

DTI and IVIM are sensitive to hamstring injuries, but suffer from long scan times. Using b-values above a certain threshold only (high-b DTI) or a simplified IVIM approach (sIVIM-DTI), which estimates the perfusion fraction and diffusion tensor, can reduce the scan time while inherently correcting DTI-indices for IVIM effects. We showed in this work that those methods provide similar sensitivity to hamstring injuries in comparison to a full IVIM-DTI fit while reducing acquisition time up to 42%. Since no difference in perfusion fraction was found between injury states, we suggest high-b DTI is the method of choice in this application.
Can Ultrafast MRI replace conventional DCE MRI in morphological evaluation and subtype classification in breast mass lesions?
Authors: Ohashi Akane , Kataoka Masako , Iima Mami , Honda Maya , Ota Rie , Urushibata Yuta , Nickel Dominic , Toi Masakazu , Zackrisson Sophia , Nakamoto Yuji
Published: August 2023

To evaluate the possibility of replacing conventional DCE MRI with UF-DCE MRI, we assessed the concordance of morphological information of the mass lesions between UF-DCE MRI and the early phase of DCE MRI. The size and shape showed excellent concordance between the two phases, while UF-DCE MRI tended to show circumscribed margin and homogeneous enhancement. In a sub-analysis, luminal subtypes demonstrated smaller size with homogeneous enhancement pattern compared with non-luminal subtypes. Predictive model for luminal subtype using the two parameters resulted in the AUC of 0.68, 0.72, for UF-DCE MRI and the early phase of DCE MRI, respectively (p=0.23).
Laminar profiling in advanced susceptibility imaging reveals variations in iron and myelin concentrations
Authors: Lee Subin , Shin Hyeong-Geol , Lee Jongho
Published: August 2023

The in-vivo imaging of iron and myelin concentrations along cortical laminae in the brain has significance in advancing knowledge about the roles of iron and myelin in brain function and in disease. In this study, we apply χ-separation, a recently developed advanced susceptibility imaging method, to explore changes in iron and myelin content throughout the cortex and into the white matter. Our findings show that iron and myelin peak at different laminar surfaces and that there is regional differences in the intensity profiles. The results suggest regional and laminar variation of iron and myelin throughout the brain.
Histological correlates of DR-HIGADOS microstructural metrics in the mouse and human liver
Authors: Grussu Francesco , Bernatowicz Kinga , Barba Ignasi , Casanova-Salas Irene , Castro Natalia , Palombo Marco , Simonetti Sara , Corral Juan Francisco , Vidorreta Marta , Merino Xavier , Mast Richard , Roson Núria , Amores Manuel Escobar , Calvo‐Malvar Nahúm , Garcia-Bennett Josep , Toledo Rodrigo , Mateo Joaquin , Nuciforo Paolo , Garralda Elena , Perez-Lopez Raquel
Published: August 2023

“Diffusion-Relaxation Hepatic Imaging via Generalised Assessment of DiffusiOn Simulations” (DR-HIGADOS) is a recent liver diffusion MRI method for intra-cellular fraction, cell size and cellularity measurement. Here we compare DR-HIGADOS metrics to counterparts from histology in two data sets: i) preclinical 9.4T MRI of formalin-fixed patient-derived xenograft mouse livers, with co-localised histological sections; ii) clinical 1.5T in vivo MRI of metastatic and primary liver cancer patients, with co-localised biopsies. Results confirm that DR-HIGADOS cell size and cellularity are histologically meaningful, paving the way to the application of the new technique in clinical studies.
39K/23Na MRI detects changes in muscular ion concentrations after exercise and in delayed-onset muscle soreness
Authors: Gast Lena , Baier Laura-Marie , Chaudry Oliver , Meixner Christian , Müller Max , Engelke Klaus , Uder Michael , Nagel Armin , Heiß Rafael
Published: August 2023

In this work, we investigated changes in the tissue potassium and sodium concentrations (TPC/TSC) of calf muscle tissue after exercise and in delayed-onset muscle soreness (DOMS) using combined 39K/23Na MRI. 14 healthy subjects were examined at baseline, directly after performing eccentric exercises and again 48h after exercise. Sodium and potassium concentrations showed inverse evolution, with changes in TSC being approximately twice as high as in TPC. Moreover, TPC was elevated in sore muscles without obvious edema, while TSC had returned to baseline or below. Thus, combined 39K/23Na MRI might help to elucidate physiological processes associated with DOMS and muscle fatigue.
MRS to assess changes in total choline as a potential marker of treatment response to choline kinase inhibition in GL261 mouse glioblastomas
Authors: Bhaduri Sourav , Sharkey Jack , Mukherjee Soham , Delikatny Edward J , Kim Sungheon G , Poptani Harish
Published: August 2023

This study investigates the effect of JAS239 on GL261 mouse glioblastoma using MRS. Higher reduction in Cho concentration and Cho/Cr ratios were observed in the tumour region than the contralateral normal brain after JAS239, indicating high sensitivity of MRS in as a pharmacodynamic marker of ChoK inhibition in glioblastomas with a potential of being an alternative treatment method.
ImUnity: a generalizable VAE-GAN solution for multicenter MR image harmonization
Authors: CACKOWSKI Stenzel , Barbier Emmanuel , Dojat Michel , Christen Thomas
Published: August 2023

ImUnity is an original deep-learning model designed for efficient and flexible MRI harmonization. A VAE-GAN network is coupled with a confusion and a biological preservation module. It ‘corrects’ MR images that can be used for various multi-center studies. Using 3 open source databases, we show that ImUnity: outperforms state-of-the-art methods in terms of quality of images generated; removes sites/scanner bias while improving patients classification; harmonizes data coming from new sites/scanners and allows the selection of multiple MR reconstructed images according to the desired applications. Tested on T1w images, ImUnity could be generalized to other types of medical images.
Reproducibility of white matter microstructure mapping with diffusion-relaxometry
Authors: Coelho Santiago , Szczepankiewicz Filip , Veraart Jelle , Chung Sohae , Lui Yvonne , Novikov Dmitry , Fieremans Els
Published: August 2023

Joint modeling of diffusion and relaxometry in white matter is attractive due to its potential to provide unique insights into tissue integrity. We designed a diffusion MRI protocol containing varying b-values, b-tensor shapes, and echo times, employed machine learning parameter estimation, and studied the reproducibility of the Standard Model (SM) parameters. We quantified scan-rescan reproducibility in six healthy volunteers for compartmental water fractions, diffusivities, and $$$T_2$$$ relaxation times. We also found good agreement between SM parameters obtained from diffusion-only data at fixed echo time, and those from joint diffusion-relaxometry acquisitions, providing a consistency check for the SM assumptions.
A novel 16-channel transmitter/32-channel receiver combined sleeve antenna and dipole array for the human whole brain imaging at 10.5 Tesla
Authors: Woo Myung Kyun , DelaBarre Lance , Waks Matt , Lagore Russell , Jungst Steve , Grant Andrea , Ugurbil Kamil , Adriany Gregor
Published: August 2023

For whole brain human head imaging at 10.5 Tesla, we interlaced a 16-channel sleeve antenna transceiver with a 16-channel asymmetric dipole antenna receiver for a combined, close fitting 16-channel transmit/32 -channel receiver array. Integration of high dielectric constant material (HDC) significantly improved receiver performance in the upper brain. Simulation results indicate excellent B1 efficiency and coverage of the combined array for the whole brain imaging at 447 MHz. To further improve array performance, we developed new on-coil transmit/receive (T/R) switches capable of preamplifier decoupling. We are now in the process of building this novel closefitting 32-channel array.
Novel Dipole/Loop Combined Arrays for Human Whole Brain Imaging at 7 T
Authors: Avdievich Nikolai , Nikulin Anton , Ruhm Loreen , Magill Arthur , Henning Anke , Scheffler Klaus
Published: August 2023

The advancement of clinical applications of 7T MRI depends heavily on the development of new RF coil designs. Recent works based on Ultimate Intrinsic SNR theory demonstrated that an optimal central SNR at 7T requires combining surface loops with dipole antennas. In this work, we developed and evaluated two novel 32-element 7T human head loop/dipole array designs. Both coils demonstrated superior Tx-efficiency, longitudinal coverage, and SNR in comparison to widely used commercial array coil. While the transceiver (TxRx)-dipole/receive(Rx)-loop array demonstrated best SNR, the TxRx-loop/Rx-dipole array showed the best Tx-efficiency. In addition, double-row TxRx-loop/Rx-dipole array provides 3D RF shimming capability.
Hippocampal Subfield Property Differences in Amnestic Mild Cognitive Impairment Measured with MR Elastography
Authors: Delgorio Peyton , Hiscox Lucy , McIlvain Grace , Merritt Alexis , Diano Alexa , Kramer Mary , Twohy Kyra , Ellison James , Lanzi Alyssa , Cohen Matthew , Martens Christopher , Johnson Curtis
Published: August 2023

The aim of this study was to determine whether magnetic resonance elastography (MRE) could sensitively detect mechanical property alterations in the hippocampal subfields due to amnestic mild cognitive impairment (aMCI) - a prodromal stage of Alzheimer’s disease (AD). Results show that entorhinal cortex viscoelasticity was significantly lower in aMCI participants. Further, the entorhinal cortex did not display significant volume differences due to aMCI, which demonstrates how MRE may yield more information about the health of a region known to harbor AD pathology. These results suggest that hippocampal subfield MRE measures show potential for use as an imaging biomarker of disease.
Quantifying Fetal Vertebral Body Calcium Changes Using Quantitative Susceptibility Mapping
Authors: Ghassaban Kiarash , Sun Cong , Wang Guangbin , Haacke Ewart
Published: August 2023

In vivo fetal vertebral calcium content was quantified using local quantitative susceptibility mapping (QSM) collected as part of a STAGE double flip angle (FA) protocol. A strong decreasing average vertebral susceptibility as a function of gestational age was seen in 54 normal fetuses including 37 cases with QSM data available at both FA’s and 17 cases with QSM at one FA totaling 91 independent datasets. An almost one-to-one linear correlation was seen between the QSM values from both FA’s. These results provide strong evidence of an in vivo MR-based quantitative technique to measure calcium development pre-term.
Persistent anosmia following COVID-19 results in significant connectivity differences within olfactory regions: a resting state fMRI analysis
Authors: Wingrove Jed , Makaronidis Janine , Prados Ferran , Kanber Baris , Yiannakas Marios , Castellazzi Gloria , Wheeler-Kingshott Claudia Gandini , Batterham Rachel
Published: August 2023

Anosmia or loss of smell is a common COVID-19 symptom. We studied a group of individuals with persistent anosmia and those who had recovered olfactory function following COVID-19 infection as well as healthy volunteers. Using resting state EPI and seed based analysis we found significant differences in connectivity between olfactory nodes and prefrontal regions known to be involved in smell processing. Furthermore, our analysis also identified connectivity differences between olfactory regions and brain areas involved in appetite control, highlighting areas of the brain that may be affected by COVID-19 related anosmia.
Improved geometric fidelity in brain DWI of pediatric patients using Multiplexed Sensitivity Encoding (MUSE)
Authors: Johansson Jens , Lagerstrand Kerstin , Ivarsson Liz , Svensson Pär-Arne , Hebelka Hanna , Maier Stephan
Published: August 2023

This study demonstrates that DWI with MUSE and RPG correction significantly reduces the geometric distortions and results in increased overall image quality without altering ADC in a pediatric patient population, compared to single-shot EPI. This improvement was confirmed both through quantitative and qualitative analysis.
Virtual Reality Patient Training for Magnetic Resonance Imaging
Authors: O'Neill Alexandra , Hargreaves Brian , Epperson Karla , Daniel Bruce , Leuze Christoph
Published: August 2023

For many patients, particularly pediatric patients, MRI exams can be intimidating primarily due to the confined space and loud noises. This can result in failed, non-diagnostic, or degraded exams at cost and even risk to the patient. We present a virtual reality application for mobile devices, such as mobile phones, of a Magnetic Resonance Imaging simulation and training software to serve as a tool for medical professionals to prepare children for MRI scans. Initial evaluations show promising results for reducing movement in test subjects and potential for reducing worry or anxiety among individuals preparing for MRI.
A rapid motion-corrected T2*-weighted multi-shot EPI technique for the Emergency Department setting
Authors: Li Zhiqiang , Ooi Melvyn , Karis John
Published: August 2023

T2*w-MRI is routinely used for the diagnosis of hemorrhage and stroke in the Emergency Department, where time is critical and motion is often a concern. However, conventional T2*w-GRE have long scan times, and often suffer from motion artifacts. Parallel imaging and compressed sensing reduce the scan time, but are still prone to motion. ssEPI is fast and motion-insensitive, but suffers from severe geometric distortions. msEPI alleviates the distortion artifacts, but at the cost of increased motion sensitivity. This work presents an msEPI with a navigator echo for rapid motion-corrected T2*w-MRI. Volunteer and patient studies have demonstrated its robustness.
Arterio-venous transit and oxygen extraction fraction before and after blood transfusion in sickle cell disease
Authors: DeBeer Tonner , Jordan Lori , Waddle Spencer , Lee Chelsea , Patel Niral , Garza Maria , Davis Larry , Pruthi Sumit , Jones Randall , Donahue Manus
Published: August 2023

Most persons with sickle cell disease (SCD) lack conventional stroke risk factors, yet nearly 50% have evidence of brain infarcts by age 30 years, indicating alternative etiologies for ischemia. We investigated whether accelerated red cell transit affects oxygen extraction and improves following transfusion-induced increases in hemoglobin. Findings suggest that evidence of accelerated capillary transit is present on arterial spin labeling (ASL) MRI, and reduces following transfusion-induced increases in hemoglobin. Furthermore, the relationship between dural ASL signal and brain oxygen extraction evolves following transfusion, suggesting that oxygen delivery is complexly dependent on blood oxygen content and capillary dynamics.
PSMA-PET vs mpMRI in prostate cancer patients with biochemical recurrence
Authors: Knudtsen Ingerid , Abrahamsen Bendik , Selnæs Kirsten , Elschot Mattijs , Langorgen Sverre , Keil Thomas , Johansen Håkon , Bertilsson Helena , Halvorsen Dag , Tandstad Torgrim , Bathen Tone
Published: August 2023

The PSMA prostate recurrence study is a multisenter prospective trial where the overall aim is to evaluate the diagnostic accuracy of 18F/68Ga-PSMA PET for detection of disease in patients with biochemical recurrence. In this preliminary analysis, we have compared the clinical imaging report of PET/CT/mpMRI to a separate evaluation of mpMRI where the radiologist was blinded to the PET results. Of 94 patients included so far, recurrent disease and/or distant metastasis was detected in 44 % (median PSA 0.4 ng/ml), according to the imaging protocol while the detection rate was 17 % for the mpMRI study scoring.
68Ga-PSMA and 68Ga-DOTA-RM2 PET/MRI in staging of high-risk prostate cancer patients: Preliminary analysis on 13 patients
Authors: Scifo Paola , Mapelli Paola , Ghezzo Samuele , Gajate Ana Maria Samanes , Preza Erik , Brembilla Giorgio , Cucchiara Vito , Ahmed Naghia , Bezzi Carolina , Savi Annarita , Neri Ilaria , Di Gaeta Ettore , Gianolli Luigi , Freschi Massimo , Briganti Alberto , De Cobelli Francesco , Picchio Maria
Published: August 2023

The use of PET/MRI scanners is an innovative approach to stage prostate cancer (PCa) and the combined use of both 68Ga-PSMA and 68Ga-DOTA-RM2 radiotracers can improve disease staging by providing different metabolic aspects of the tumour. In the present study, 13 patients with high-risk PCa undergoing 68Ga-PSMA and 68Ga-DOTA-RM2 PET/MRI before radical prostatectomy have been included, with availability of histology as gold standard to validate intraprostatic findings and local extension. Our results suggest that the use of PET/MRI with a dual tracer approach can improve PCa staging, by providing complementary information ameliorating disease characterization.
Pilot Tone meets DISORDER: Improved data-driven motion-corrected brain MRI by leveraging Pilot Tone signal variations
Authors: Brackenier Yannick , Wilkinson Thomas , Cordero-Grande Lucilio , Tomi-Tricot Raphael , Bridgen Philippa , Giles Sharon , De Vita Enrico , Malik Shaihan , Hajnal Joseph
Published: August 2023

DISORDER is an established retrospective data driven motion correction approach that uses optimised phase encoding, but otherwise unmodified 3D acquisitions. It is highly effective, but requires multiple lines of k-space to be grouped together for each motion state to be estimated, and this limits temporal resolution. At 7T, head motion can also be detected by “Pilot Tone”, which is an injected RF signal picked up by each coil in the head receiver array, but a calibration step is required. Here we combine DISORDER and Pilot Tone to achieve integrated calibration and show that improved motion correction can result.
MoDGAN: Unsupervised rigid motion detection and correction with generative adversarial networks
Authors: Park Mu-Yul , Lee Seul , Jung Kyu-Jin , Yun Jisu , Kim Dong-Hyun
Published: August 2023

Rigid motion artifacts, which are caused by subject’s motion during MRI acquisition, are a significant problem of image degradation. In this study, we propose a GAN-based method for unsupervised rigid motion detection and correction. The proposed method detects the motion-corrupted phase encoding lines using an anomaly score for motion detection. To reduce motion artifacts, we replace them with corresponding lines that generator yielded. We show that proposed method achieves high accuracy in detecting motion-corrupted line without any hardware or modification in sequence. Furthermore, the results of motion correction also showed noticeable performance.
Optimized denoising and removal of partial-Fourier induced Gibbs ringing improves accuracy and robustness of DTI and DKI parameters
Authors: Chen Jenny , Ades-aron Benjamin , Lee Hong-Hsi , Kullakanda Durga , Maithani Saurabh , Novikov Dmitry , Veraart Jelle , Fieremans Els
Published: August 2023

Diffusion MRI (dMRI) is affected by noise and by artifacts such as Gibbs ringing and distortions. Using software phantoms as ground-truth, this study compares diffusion tensor imaging (DTI) and diffusional kurtosis imaging (DKI) parameter estimates to assess accuracy of various denoising and Gibbs removal methods, two key components of dMRI pipelines. An optimized Diffusion parameter EStImation with Gibbs and NoisE Removal (DESIGNER) pipeline is proposed, with non-local patch MP-PCA denoising and Removal of Partial-fourier induced Gibbs Ringing (RPG), that yields more accurate metrics, fewer outlier voxels in phantoms and more robust DTI/DKI maps in patient data.
Optimal b-value sampling for interstitial fluid estimation in cerebral IVIM imaging, a genetic algorithm approach
Authors: Drenthen Gerhard , Jansen Jacobus , van der Thiel Merel , Voorter Paulien , Backes Walter
Published: August 2023

Besides the parenchymal diffusion and microvascular pseudo-diffusion, a third diffusion component was previously found in cerebral intravoxel incoherent motion (IVIM), representing interstitial fluid. However, estimating this intermediate IVIM component can be challenging, since spectral decomposition techniques have strong dependence on the number of samples (i.e. acquired b-values) and SNR. Therefore, it is important to know which b-values are essential to be acquired. In this study, an optimal b-value sampling for estimating the intermediate component is derived using a genetic algorithm. The optimal sampling (0,20,100,270,280,370,540,650,660,710,720,790,980,990,1000 s/mm2) was shown to outperform linear and logarithmic samplings, for both simulated and in vivo data.
Testing the feasibility and effectiveness of bundle-based global tractography (bundle-o-graphy) in real human brain data
Authors: Battocchio Matteo , Schiavi Simona , Descoteaux Maxime , Daducci Alessandro
Published: August 2023

We introduce a new formulation for bundle-based tractography global reconstruction (bundle-o-graphy). The idea is to move the focus from streamlines to bundle-based reconstruction thanks to a convenient reduction in the number of parameters needed to be optimized and the injection of anatomical priors. We show the potential of our approach on both synthetic and real data.
A new framework to build high quality tractography-based DWI brain templates using COMMIT
Authors: Stones Richard , Beyh Ahmad , Barrett Rachel , Daducci Alessandro , Dell'Acqua Flavio
Published: August 2023

In this study we present a novel method for building high quality tractography-based DWI brain templates. We use streamline normalisation to obtain the correct anatomical fibre orientation information in template space and then regenerate the diffusion signal using the COMMIT framework. The template fODF field and tractography reconstructions show good anatomical agreement with well known white matter structures. This framework could provide new templates, atlases and tools for normalisation of DWI data, and simplify the creation of realistic DWI phantoms.
QSMRim-Net: Fusing Radiomic and Convolutional Features for Identification of Chronic Active MS Lesions on Quantitative Susceptibility Maps
Authors: Zhang Hang , Zhang Jinwei , Marcille Melanie , Spincemaille Pascal , Nguyen Thanh , Gauthier Susan , Wang Yi , Sweeney Elizabeth
Published: August 2023

Chronic active multiple sclerosis (MS) lesions are characterized on Quantitative susceptibility mapping (QSM) by a paramagnetic rim (rim+) at the edge of the lesion. We present QSMRim-Net, a deep neural network that fuses lesion-level radiomic and convolutional image features together for automated identification of rim+ lesions on MRI. On the lesion-level, using five-fold cross validation, the proposed QSMRim-Net detected rim+ lesions with an area under the receiver operating characteristic curve of 0.965 and an area under the precision recall curve of 0.655. QSMRim-Net out-performed other state-of-the-art methods on both metrics.
Multi-Component T2 Characterization of Lesions in Pediatric Onset Multiple Sclerosis
Authors: Vasylechko Serge , Machado-Rivas Fedel , Jaimes Camilo , Gorman Mark , Benson Leslie , Warfield Simon , Kurugol Sila , Afacan Onur
Published: August 2023

This study evaluated myelin water fraction (MWF) estimates in chronic MS lesions against contralateral normal appearing white matter (NAWM) of pediatric onset MS patients (POMS). Accelerated 2D multi-slice CPMG acquisitions provided near full brain coverage. Two methods were used to estimate the myelin fractions, as well as intra-/extra- axonal (IE) associated water and CSF water. Significant differences were found between the group measures. Further comparison of NAWM in POMS showed significant differences with whole-white matter in a control group. Our results support that a multi-component T2 analysis can provide quantitative insights into lesional and non-lesional disease burden in POMS.
Investigation of asymmetric undersampling scheme in accelerated flow imaging for improving velocity and turbulence kinetic energy estimation
Authors: Park Kyoung-Jin , Ha Ho-Jin , Yang Dong-Hyun , Ryu Kang-Hyun , Lee Jae-Hun , Kim Dong-Hyun
Published: August 2023

Compressed sensing (CS) technique has recently been used to accelerate long acquisition time in 4D Flow. However, it aggravates underestimation in velocity calculation and overestimation in turbulent kinetic energy (TKE) estimation, when under-sampling is applied. An asymmetric undersampling scheme method of the reference image and velocity encoding images could alleviate problems. The purpose of this paper is investigation of improving velocity and turbulence kinetic energy estimation with an asymmetric reduction for two motion encoding schemes (i.e., conventional 4D Flow vs ICOSA6 Flow)
MRI Regularization for Low-Count PET Image Recovery using Unsupervised Learning Without the Need of Training Set - A Multi-Tracer PET/MRI Study
Authors: Serrano-Sosa Mario , Huang Chuan
Published: August 2023

Unsupervised denoising is useful as it allows low-count PET image recovery without the need of paired training data(low-count/full-count). However, current unsupervised denoising models utilize Contrast-to-Noise Ratio as stopping criteria to optimize the image recovery process, which can be improved by considering structural information to maintain the integrity of gross anatomy. In this work, we proposed an MRI structural regularization loss function for low-count PET image recovery using an unsupervised learning model, which does not require paired training sets and demonstrated that the proposed method is superior in both qualitative and quantitative analyses for two radiotracers with very different physiological uptake.
Assessment of Instabilities of Conventional and Deep Learning Multi-Coil MRI Reconstruction at Multiple Acceleration Factors
Authors: Zi Ruoxun , Johnson Patricia , Knoll Florian
Published: August 2023

Although deep learning has received much attention for accelerated MRI reconstruction, it shows instabilities to certain tiny perturbations resulting in substantial artifacts. There has been limited work comparing the stability of DL reconstruction with conventional reconstruction methods such as parallel imaging and compressed sensing. In this work, we investigate the instabilities of conventional methods and the Variational Network (VN) with different accelerations. Our results suggest that CG-SENSE with an optional regularization is also impacted by perturbations but shows less artifacts than the VN. Each reconstruction method becomes more vulnerable with higher acceleration and VN shows severe artifacts with 8-fold acceleration.
Improved Detection and Localization of Artifacts using CutArt Augmentation
Authors: Duffy Ben , Zaharchuk Greg , Gong Enhao , Datta Keshav
Published: August 2023

With the aim of improving the performance of an automated quality control system, we propose to use a data augmentation technique based on cropped patches of simulated artifacts (CutArt) instead of artifacts that are distributed across the entire image. This has the advantage of improving the artifact localization and quality control classification performance, as assessed by experiments on simulated as well as real artifact affected data. Localization experiments suggested that the CutArt model learns to focus on the tissue of interest instead of the image background.
On Measuring the Pore Distribution Function and the Occurrence of Signal Peaks When Utilizing Long Diffusion Gradients
Authors: Stuprich Christoph , Kuder Tristan , Hensel Bernhard , Uder Michael , Laun Frederik
Published: August 2023

In Diffusion MR, short gradient pulses are often ascribed to generate oscillating signal curves. These characteristic oscillations or “peaks” appear if a certain characteristic length-scale in the underlying tissue is present. Mitra and Halperin mention the possibility of “Bragg Peaks” when using long gradient pulses. In this work we explicitly show and interpret the occurrence of such signal peaks under application of long gradient pulses in theory and simulation.
Characterizing spectral and temporal effects of heart rate variability on resting-state BOLD signals using wavelet transform coherence
Authors: Lee Quimby , Chen Jingyuan , Wheeler Gregory , Fan Audrey
Published: August 2023

Heart rate variability (HRV), which is reflective of autonomic regulation, induces vascular effects in low (0.05-0.15Hz) and high (0.15-0.4Hz) frequency bands that can influence the blood oxygen level dependent (BOLD) signal of resting-state functional magnetic resonance imaging (rsfMRI). In this study, we utilized a wavelet transform coherence analysis to identify spectral and temporal differences in phased-locked behavior between HRV and resting-state network (RSN) time courses. Subjects differed in the frequency band with greatest time-averaged coherence and percentage of time with significant coherence of HRV and RSN signals.
Performance of Quantitative, Free-breathing 3D Perfusion CMR using Motion-Informed LLR Reconstruction in a Porcine Infarction Model
Authors: Hoh Tobias , Vishnevskiy Valery , Stoeck Christian , Waschkies Conny , Cesarovic Nikola , Weisskopf Miriam , Fuetterer Maximilian , Kozerke Sebastian
Published: August 2023

Three-dimensional first-pass myocardial perfusion CMR requires acceleration methods to enable whole-heart coverage in a limited acquisition window. Current 3D approaches suffer from data inconsistencies during free breathing, compromising image quality and perfusion quantification. We propose and experimentally validate a combination of Cartesian pseudo-spiral k-t undersampling with respiratory motion-informed locally low-rank (MI-LLR) reconstruction for robust whole-heart myocardial quantitative perfusion CMR in an experimental pig model of myocardial infarction. As reference, standard 2D acquisitions are used. Overall, image quality scoring was good. Perfusion defects were equally well depicted and discernible in imaging and MBF perfusion mapping in 3D and 2D approaches, respectively.
31P-MRS reveals oxidative capacities of red and white fibers in human muscle differ 7-fold in vivo
Authors: Jeneson Jeroen , Habets Laura , Hooijmans Melissa , van den Berg Sandra , Bartels Bart , van der Pol W , Nederveen Aart
Published: August 2023

31P MRS has been used to non-invasively diagnose muscular mitochondrial dysfunction in disease. However, shifts in muscle fiber type composition due to muscle disuse are potential confounders since mitochondrial and capillary densities differ between fiber types. We obtained new quantitative information on this subject matter on basis of dynamic in vivo 31P MRS recordings from upper arm muscle of fourteen healthy subjects performing a maximal arm-cycling test. Analysis of the post-exercise time course of Pi in red and white myofiber pools distinguished by myoplasmic pH revealed a sevenfold difference in oxidative capacity between these fiber types in vivo.
Deep learning reconstruction enables accelerated acquisitions with consistent volumetric measurements
Authors: Lebel R. Marc , Kaushik Suryanarayanan , Kolupar Trevor , White Nate , Luo Weidong , Banerjee Suchandrima
Published: August 2023

This work evaluates brain volumetry measurements obtained from T1w images with fast (PI) and rapid (PI+CS) protocols (< 3 mins) and reconstructed with AIR Recon DL 3D, a deep learning-based reconstruction to reduce noise and ringing. Images were segmented using FDA-cleared software NeuroQuantÒ for quantitative volumetric analysis. Segmentation was successful in all cases and key brain volumes are unchanged between fast and rapid protocols, and further between conventional and DL reconstructions. This work demonstrates that highly accelerated acquisitions and advanced reconstruction methods are suitable for segmentation and volumetric studies and can improve repeatability of measurements.
A simulation framework to assess the quantification reliability of 2HG in 1H MRS
Authors: Platek Justyna , Franke Vanessa L. , Ladd Mark E. , Bachert Peter , Korzowski Andreas
Published: August 2023

The non-invasive detection of 2-hydroxyglutarate (2HG) via 1H MRS is of particular interest in brain tumors, but quantification of 2HG may be challenging due the spectral overlap with Glutamate and Glutamine. In this study, we implemented a simulation framework for the assessment of the quantification reliability for 2HG under realistic conditions, and demonstrated its application to a PRESS sequence at B0=9.4T with a representative set of different TEs and SNR levels. With this framework, we aim to identify optimal acquisition parameters for the detection of 2HG in glioma mouse models at a 9.4-T small animal scanner in the future.
Model-Based Reconstruction with Automatic Differentiation for Single-Shot Myocardial T1 Mapping using Radial MOLLI with FLASH Readout
Authors: Wang Xiaoqing , Blumenthal Moritz , Scholand Nick , Uecker Martin
Published: August 2023

A nonlinear operator for radial MOLLI is constructed in BART, allowing accurate derivative calculation via automatic differentiation. The constructed nonlinear MOLLI operator is further integrated into a model-based reconstruction framework where myocardial $$$T_{1}$$$ maps are reconstructed directly from undersampled k-space data. Results on an experimental phantom and one healthy subject have demonstrated that high resolution ($$$1.0 \times 1.0 \times 6$$$ mm$$$^{3}$$$) myocardial $$$T_{1}$$$ maps can be achieved within 4 heartbeats with good accuracy and precision using the proposed method.
Consistent and Accurate 3T Cardiac End-Systolic Adiabatic T2-Mapping
Authors: Beyers Ronald , Denney Thomas
Published: August 2023

Cardiac T2-mapping is ideal for assessing myocardial edema resulting from events, such as, acute myocardial infarction, myocarditis and tako-tsubo cardiomyopathy. While many T2mapping sequences exist, most have design shortcuts that degrade their consistency, accuracy and prognostic value. T2maps captured at end-systole (ES) have maximum wall thickness and fewest artifacts and 4-point T2 curve-fits provide good T2 estimates. We present an Adiabatic T2-Prep Mapping sequence that produces accurate 4-point T2maps at ES within a 22-second breath hold at 3T. Pretesting on phantoms and in vivo validation on healthy human volunteers presented superior results.
Deep Learning and Fat Fraction Based Analysis of Calf MRI in Diabetic Patients Following Exercise Intervention
Authors: Shah Jill , Shah Tanay , Rajamohan Haresh , Medina Katherine , Rao Smita , Deniz Cem , Brown Ryan
Published: August 2023

Diabetic peripheral neuropathy (DPN) is characterized by increased adiposity implicated in metabolic dysfunction. Proton-based Dixon MRI is an appropriate means to quantify adiposity, but analysis requires time-consuming manual image segmentation. To address this problem, we developed an automated segmentation algorithm based on convolutional neural networks that provided high dice similarity coefficient scores (>0.88) on multiple regions of interest (ROI) within the calf. We utilized the networks to analyze fat fraction trends in individuals with DPN following a 10-week supervised exercise program. We measured decreased adiposity in the combined calf interstitial and muscle space (P<0.1) but not in individual muscle ROIs.
Intra-Subject Variability of Skeletal Muscle Glycogen Using 13C/1H MRS at 3T Using a Novel Standardization Method
Authors: Nagarajan Rajakumar , Layec Gwenael , Kent Jane
Published: August 2023

Given its central role in substrate metabolism, the ability to quantify muscle glycogen (Gly) continuously and noninvasively using natural abundance 13C MR spectroscopy presents an important opportunity for understanding human metabolism. This study evaluated the reproducibility of Gly measured by 13C MRS in the quadriceps muscle using three methods for signal standardization at 3T: Gly/total creatine (TCr) from 13C, Gly/TCr using 13C and 1H, and Gly/water. The novel results from this study suggest that Gly/TCr measurements using the creatine peak from 1H MRS is highly reproducible and may be an advantageous approach to measuring muscle glycogen in the future.
Diffusion-weighted MEGA-PRESS spectroscopy
Authors: Berg Emile , Seland John Georg
Published: August 2023

The editing capabilities of the MEGA-PRESS sequence are combined with diffusion-weighing to enable both quantification and diffusion measurements of less abundant brain metabolites. The technique, labelled DW-MEGA-PRESS, was tested for combined editing and diffusion-weighting of GABA. Obtained data give reliable results for GABA concentrations and corresponding diffusion coefficients from in vitro experiments. When applied to in vivo acquisitions, reliable diffusion coefficients for the dominating metabolites were obtained. GABA could be reliably quantified, but the signal-to-noise ratio was not sufficient for a reliable determination of its diffusion coefficient. This could be improved by further optimization of scanning and post-processing protocols.
Super-resolution mean diffusivity spectroscopic MRI in the human brain
Authors: Avram Alexandru , Kulam Magdoom , Sarlls Joelle , Freidlin Raisa , Basser Peter
Published: August 2023

We describe a comprehensive pipeline for super-resolution reconstruction of clinical diffusion-weighted MRIs acquired with isotropic diffusion encoding (IDE), or spherical tensor encoding. The pipeline integrates blip-up/down EPI distortion correction and slice-to-volume registration (SVR). Multiple low-resolution IDE-MRIs with different slice orientations relative to the brain are processed to reconstruct high-resolution IDE-MRIs. From high-resolution IDE-MRIs with a wide range of b-values we estimate spectra of subvoxel MD values to describe the distribution of water mobilities in microscopic brain tissue microenvironments. Integrating SVR-reconstruction with IDE is an important step in the clinical translation of MD spectroscopic MRI for fetal MRI applications.
Parahydrogen-Induced Polarization Relayed via Proton Exchange: Application to biological molecules.
Authors: Them Kolja , Hövener Jan
Published: August 2023

Parahydrogen-induced polarization relayed via proton exchange (PHIP-X) is a new method to hyperpolarize a variety of molecules that participate in suitable fast proton exchange with allyl alcohol. The combination of the wide applicability of polarization-transfer via proton exchange and the strong polarization obtained using hydrogenative of PHIP opens up new avenues to hyperpolarize biological molecules such as glucose, lactate and pyruvate. Hence, PHIP-X provides a promisingnew platform for potential applications in metabolic MRI.
Respiratory System Resistance Explained using Hyperpolarized 129Xe MRI Texture Features and Machine Learning
Authors: McIntosh Marrissa , Sharma Maksym , Matheson Alexander , Kooner Harkiran , Eddy Rachel , Licskai Christopher , McCormack David , Nicholson Michael , Yamashita Cory , Parraga Grace
Published: August 2023

129Xe MRI ventilation images consist of embedded texture features that may help explain ventilation heterogeneity. We previously showed that 129Xe MRI ventilation features predicted response to biologic therapy in asthma and thus, we postulated that texture features may help explain central and peripheral airways resistance. We employed machine-learning techniques to identify specific 129Xe MRI features that were related to airway resistance. Ventilation texture analysis yielded four unique and two common features that independently explained central and peripheral airways resistance, respectively. These promising results suggest that 129Xe ventilation texture analysis may reveal hidden anatomic-physiologic measurements that lead to ventilation heterogeneity.
A Monte Carlo Analysis of Guidewire Safety Comparing a Body and Local Coil Array
Authors: godinez felipe , Hand Jeffrey , Teixeira Nuno , Steensma Bart , Hajnal Joseph , Raaijmakers alexander , malik shaihan
Published: August 2023

Metallic Endovascular devices can be unsafe when used during MR guided procedures. A potential solution to the heating problem might be to use a local coil instead of a body coil to excite the imaging volume. In this work we present a Monte Carlo analysis using many random guidewire trajectories and the transfer function to estimate the scatter electric field at the guidewire tip imbedded in a heterogenous dielectric.
Detection of enhanced cerebrospinal fluid transport during dexmedetomidine anesthesia in the rat using diffusion, T2 and morphometric MRI
Authors: Hutchinson Elizabeth , Romero-Lozano Anakaren , Galons Jean-Pierre , Howison Christine , Avram Alexandru , Williamson Nathan , Komlosh Michal , Basser Peter
Published: August 2023

The enhancement of CSF transport in a robust experimental model was measurable using in-vivo quantitative MRI.TBM and voxelwise T2 mapping analysis were both able to changes in regions that are known to be associated with CSF transport based on contrast-enhancement studies. These two methods do not require contrast and if validated could provide a non-contrast outcome metric for health of the CSF transport system. Diffusion MRI outcomes suggest that it may be possible to sensitize the diffusion MRI paradigm to CSF transport and this is an area for future research.
In vivo CSF Flow During Central Sensitization Using Fourier Velocity Encoded MRI at 21.1 T
Authors: Richter Dayna , Holder Samuel , Grant Samuel
Published: August 2023

Cerebrospinal fluid (CSF) flow was evaluated temporally in a preclinical migraine model at 21.1 T. As elevated sodium levels are implicated in the progression of migraine, evaluating how sodium is transported in the ventricular system and brain should provide insight on bulk sodium accumulation around, among and within anatomical regions implicated in migraine. A series of Fourier Velocity Encoding MRI was acquired over 2 h post-nitroglycerin injection to evaluate CSF flow during the progression of central sensitization.
Altered neurovascular coupling in patients with MELAS evaluated by combining cerebral blood flow and regional homogeneity
Authors: Wang Rong , Li Yuxin , Lin Jie , Zhang Yong
Published: August 2023

This is the first study that used a combined arterial spin labeling (ASL) and resting-state fMRI approach to assess the neurovascular coupling in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), which may provide a new mechanistic perspective into understanding numerous brain diseases.
Non-invasive assessment of blood-brain barrier permeability in multiple sclerosis patients by arterial spin labeling.
Authors: Paschoal Andre , Boaventura Mateus , Petitclerc Leonie , van Osch Matthias , Otaduy Maria , Apostolos-Pereira Samira Luisa , Callegaro Dagoberto , Rimkus Carolina
Published: August 2023

Multiple sclerosis is a demyelinating disease affecting the central nervous system. Although MS lesions can be identified by conventional MRI, the evaluation of active lesions in normal appearing gray and white matter requires measures of blood-brain barrier permeability (BBB), which is commonly assessed through the dynamic contrast enhanced (DCE) acquisition. When repeated scans are needed in the MS patients follow-up, repeated gadolinium injection is not recommended. This study successfully showed the feasibility of advanced arterial spin labeling sequences as an alternative to evaluate BBB permeability, whose results of water-exchange times across the BBB were in agreement with DCE measurements.
Oxygen Extraction Fraction is higher in elderly participants with a higher cardiovascular disease risk; a combined QSM and ASL study
Authors: McFadden John , Matthews Julian , Scott Lauren , Herholz Karl , Dickie Ben , Haroon Hamied , Sparasci Oliver , Ahmed Saadat , Kyrtata Natalia , Parker Geoffrey , Emsley Hedley , Lohezic Maélène , Parkes Laura
Published: August 2023

We investigated quantitative susceptibility mapping (QSM) and arterial spin labelling (ASL) to measure cerebrovascular parameters in elderly people with a range of vascular disease risk (QRisk) and cognitive impairment. Cerebral blood flow (CBF) and arterial transit time (ATT) were derived from ASL and oxygen extraction fraction (OEF) from QSM. Regional estimates were obtained by matching six large veins to their draining territories. QRisk had a significant positive relationship with ATT. OEF had a significant compensatory increase with altered ATT and CBF. Both OEF and ATT were found to be elevated with impaired cognition.
Repeatability and reliability of 2D phase-contrast and 4D flow MRI when measuring cerebral arterial and venous pulsatility
Authors: Morgan Alasdair , Thrippleton Michael , Jin Ning , Wardlaw Joanna , Marshall Ian
Published: August 2023

We examined the test-retest repeatability and intraobserver reliability of 4D flow MRI while assessing the pulsatility and flow rates of a variety of cerebral arteries and veins in healthy volunteers. A subset of these vessels were also measured using 2D phase-contrast MRI, a more established method, to assess the level to which the lower-resolution (but higher-coverage) 4D method could compare to its 2D counterpart. Flow pulsatility appears to play a role in the development of cerebral small vessel disease and so testing the capabilities of 4D flow in this context is an important step before applying it to clinical studies.
IVIM Diffusion-Weighted MRI in Detecting Graft Function with Complications Immediately After Kidney Transplantations
Authors: Chai JyhWen , Chang Yung-Chien , Pan Kuan-Jung , Chung Mu-Chih , Chen Hsian-Min , Chiu Feng-Mao
Published: August 2023

Delayed graft function (DGF) is a form of acute renal failure that results in post-transplantation oliguria, with various frequencies from 2% to 50%. Heretofore, there was a lack of imaging biomarkers to interpolate the DGF. The tri-exponential intravoxel incoherent motion (IVIM) model, providing three distinct signal fractions of a pure diffusion, an intermediate and an ultrafast component, is more preferable for the diffusion signal in the allograft kidneys than the mono- and bi-exponential models. Our experiment illustrates that tri-exponential IVIM model could provide a good indicator for distinguishing the early graft function, the delayed graft function without and with complications.
Disentangling the contributions of myelin, neurofilament & microglia to MR contrast: an automated pipeline for voxelwise MR-histology analysis
Authors: Kor Daniel , Jbabdi Saad , Mollink Jeroen , Huszar Istvan , Foxley Sean , Pallebage-Gamarallage Menuka , Scott Connor , Smart Adele , Ansorge Olaf , Miller Karla , Howard Amy
Published: August 2023

Acquisition of MRI and histology in the same ex-vivo tissue sample enables direct correlation between MR and histologically-derived metrics. Here, we analysed immunohistochemistry images of human visual cortex, anterior cingulate and hippocampus to produce stained area fraction maps for myelin, neurofilaments and microglia. We performed voxelwise correlations between MR parameters (FA, MD, R2*, R1) and histology maps to generally characterise the strength of relationships. We then used partial correlation to identify the unique variance in MR parameters explained by each histological feature, and multiple linear regression to explore how well multiple microstructural properties can together explain MR parameters.