bluuebunny/crossref_metadata_2025 huggingface dataset:
EDDEN: Towards a framework for Evaluating Diffusion MRI DENoising approaches
Authors: Patron Jose Pedro Manzano , Moeller Steen , Yacoub Essa , Sotiropoulos Stamatios
Published: August 2023

Denoising diffusion MRI data has gained significant interest over the last years, due to the inherently low-SNR in the dMRI signal. Despite the existence of a number of denoising algorithms, open questions exist on how, and even whether, to denoise data. A consistent set of evaluations that comprehensively characterise newly-developed approaches and their impact on downstream applications is lacking for providing insight to these questions. Here we propose EDDEN, a framework for Evaluating DMRI DENoising approaches, consisting of a set of unique data and assessments. We demonstrate its use using 3 exemplar denoising methods (NLM, MPPCA and NORDIC).
Triplanar Ensemble Detection Network (TPE-Det): A Single End-to-End Model for Efficient Detection of Cerebral Microbleeds in MR Images
Authors: Lee Haejoon , Al-masni Mohammed , Kim Jun-Ho , Lee Seul , Jung Kyu-Jin , Kim Woo-Ram , Noh Young , Kim Dong-Hyun
Published: August 2023

Automated detection of Cerebral Microbleeds (CMBs) in Magnetic Resonance (MR) images can be clinically useful because of the small size of CMBs and the presence of numerous mimics. In this study, we propose an end-to-end Triplanar Ensemble Detection Network (TPE-Det) that demonstrates notable performance with only a single stage. Via the proposed TPE-Det, we combined CMBs detection results from axial, sagittal, and coronal planes. When considering the additional planes, the average False Positives per patient (FPavg) decreased from 29.16 to 0.92 compared to the case of using only the axial plane, preserving the high sensitivity of 95.94%.
SWISeR: Multi-Field Susceptibility-Weighted Image Super-Resolution
Authors: Roberts Alexandra , Spincemaille Pascal , Kovanlikaya Ilhami , Tsiouris Apostolos John , Nguyen Thanh , Wang Yi
Published: August 2023

Susceptibility-Weighted Imaging Super-Resolution (SWISeR) increases the apparent resolution of input images and improves image quality, measured by mean-squared error and clinical scoring. This method generalizes to healthy subjects scanned at 3T and 7T and subjects imaged at 1.5T and 3T.
Rapid 3D Quantitative Mapping of Brain Metastases with Deep Learning-Based Phase-Sensitive MR fingerprinting
Authors: Yu Victoria , Tringale Kathryn , Otazo Ricardo , Cohen Ouri
Published: August 2023

In MR fingerprinting, quantitative maps are obtained by matching the measured signal to a pre-computed dictionary. However, a key constraint of dictionary matching is the exponential growth of the dictionary with the number of parameters. A deep learning method named DRONE overcomes this constraint by using deep learning to map the magnitude-valued signal to the underlying tissue parameters. Here we describe an extension of DRONE that jointly estimates a phase term to enable mapping complex-valued signals and improve the quantitative accuracy. We test the accuracy in the ISMRM NIST phantom and demonstrate the clinical utility in patients with brain metastases.
R1ρ Dispersion Imaging of Normal Tissues in Human Subjects at 3T
Authors: Adelnia Fatemeh , Zu Zhongliang , Wang Feng , Sengupta Saikat , Harkins Kevin , Gore John
Published: August 2023

R1ρ dispersion over a range of weak locking fields has the potential to reveal information on microvascular geometry and density based on diffusion effects. Using an efficient protocol for data acquisition and theoretical fits to a simple model we present estimates of novel parameters derived from R1ρ dispersion measurements that are in the range expected for microvasculature structure. Our in vivo results support the application of R1ρ dispersion at low locking fields in human studies. However, further validation such as ex vivo studies need to be performed.
Multi-echo Complex QSM+qBOLD (mcQQ) for Oxygen Extraction Fraction (OEF) mapping
Authors: Cho Junghun , Zhang Jinwei , Spincemaille Pascal , Zhang Hang , Nguyen Thanh , Gupta Ajay , Wang Yi
Published: August 2023

Quantitative mapping of oxygen extraction fraction (OEF) is critical to evaluate brain tissue viability and function in neurologic disorders. An integrated model of QSM and qBOLD (QSM+qBOLD or QQ) has been developed to map OEF from a routine gradient echo MRI without the need for vascular challenges, and QQ inversion can be obtained using deep learning. This study proposes a multi-echo complex QQ (mcQQ) that improves fidelity to data noise characteristics using complex domain. The proposed mcQQ provided more accurate OEF in simulation and an improved sensitivity to OEF abnormalities in ischemic stroke patients, compared to the current QQ method.
BraCoil – a wearable one-size-fits-all breast coil for 3 T MR mammography
Authors: Obermann Michael , Nohava Lena , Roat Sigrun , Frass-Kriegl Roberta , Soanca Onisim , Gruber Bernhard , Ginefri Jean-Christophe , Felblinger Jacques , Laistler Elmar
Published: August 2023

In this work, we present a new approach for MR mammography with a wearable light-weight coil array (“BraCoil”) covering both breasts and the sentinel axillary lymph nodes. The coil can be worn like a vest over a T-shirt and used either in prone or supine position. The presented design might be able to overcome numerous shortcomings of the current state-of -the-art in breast imaging by improving sensitivity, comfort and intimacy, shortening measurement time and may thereby eventually enable large-scale breast cancer screening without ionizing radiation.
8-Channel Dipolectric Antenna Array for MRI at 7T: Proof-of-Principle Study in Human Brain
Authors: Wenz Daniel , Xin Lijing
Published: August 2023

In this work we introduce a new type of antenna for ultrahigh field MRI which combines the advantages of dielectric resonator and dipole antennas: dipolectric antenna. Numerical simulations were performed to benchmark our concept against a loop-dipole antenna, and significant transmit efficiency gains in the peripheral as well as deeper located regions were observed. An 8-channel dipolectric antenna array was developed, and evaluated at the bench as well as in phantom experiments. In vivo MRI/MRS experiments at 7T were conducted and it was demonstrated that dipolectric antennas can be a promising approach for ultrahigh field MRI.
Diffusely abnormal white matter microstructural changes are similar across the clinical phenotypes of multiple sclerosis
Authors: Vavasour Irene , Becquart Pierre , Joseph Tigris , Gill Jasmine , Zhao Guojun , Abdullahi Farhia , Kamma Emily , Frese Kaya , Carruthers Robert , Kolind Shannon , Schabas Alice , Sayao Ana-Luiza , Devonshire Virginia , Tam Roger , Moore GR Wayne , Stukas Sophie , Wellington Cheryl , Quandt Jacqueline , Traboulsee Anthony , Li David , Laule Cornelia
Published: August 2023

Diffusely abnormal white matter (DAWM) is commonly found on conventional brain MRI in all stages of multiple sclerosis (MS). Blood markers associated with prior or ongoing myelin and axonal damage were not found to be elevated in people with DAWM relative to people without DAWM. Within areas of DAWM, no differences between MS phenotypes were found possibly suggesting that the tissue abnormalities within DAWM are similar across the clinical course, from early to late stages of MS.
In pursuit of the central vein sign in multiple sclerosis in the cervical spinal cord at 7T
Authors: Robison Ryan , Witt Atlee , Combes Anna , O'Grady Kristin , Prock Logan , Houston Delaney , Martin Dann , Clarke Margareta , Smith Seth
Published: August 2023

Central vein sign is believed to be a specific marker for the diagnosis of multiple sclerosis (MS) but has not yet been reported in the spine. This work used SWI in the cervical spinal cord of MS patients and healthy controls at 7T to look for evidence of central veins. SWI hypointensities were observed frequently around the cord periphery, between the white and grey matter within the cord, and along nerve roots. Hypointensities were also observed within spinal cord lesions, providing candidate evidence of central veins in lesions of the spinal cord.
Mapping the myelin bilayer with short-T2 MRI: Application to ex-vivo multiple sclerosis brain tissue
Authors: Baadsvik Emily Louise , Weiger Markus , Froidevaux Romain , Faigle Wolfgang , Ineichen Benjamin Victor , Pruessmann Klaas Paul
Published: August 2023

Signal from the myelin bilayer can be captured using dedicated short-T2 imaging techniques, and analysis methods to isolate the contribution of the bilayer from other signal sources have been proposed. However, such analysis methods are often validated on samples in which the background water signal has been suppressed. Thus, it is unclear whether these techniques can successfully map myelin content in a clinical setting. Here, we apply and evaluate a previously proposed technique for myelin mapping to multiple sclerosis brain tissue without water suppression. We conclude that the quality of the myelin maps is comparable to that of water-suppressed samples.
Evaluation of a full dynamic density adapted radial 4D-pcASL angiography sequence exploiting B1+-shimming and ramped SPINS excitation at 7T
Authors: Meixner Christian , Müller Max , Schmitter Sebastian , Herrler Jürgen , Dörfler Arnd , Uder Michael , Nagel Armin
Published: August 2023

In this work, a whole-brain 4D-pcASL angiography sequence exploiting a radial density-adapted gradient echo readout with golden angle sampling was implemented and evaluated on a 7T system. Various parallel transmission (pTx) strategies were compared to the standard circularly polarized mode: To counteract low transmit efficiency in the labeling, B1+-shimming was used in combination with a full spiral-nonselective pTx-optimized readout train. Further, constant flip angle pTx-excitations in the readout were compared to pTx-pulses that were ramped from 3.5° to 6.5° using a linear scaling factor. This ramped readout strategy outperforms constant flip angles and reveals more of the vascular tree
Associations between cerebral microvascular hemodynamics and white matter lesion burden in typically aging older adults
Authors: Juttukonda Meher , Stephens Kimberly , Yen Yi-Fen , Howard Casey , Polimeni Jonathan , Rosen Bruce , Salat David
Published: August 2023

Hypoperfusion is frequently considered a cause of age-related white matter lesions (WML). However, reductions in oxygen availability to brain tissue may also be caused by impaired oxygen extraction fraction (OEF). Here, we tested the hypothesis that venous hyperintense signal (VHS) in arterial spin labeling (ASL) MRI is indicative of impaired OEF in typically aging older adults. In participants aged 60–80 years (n=40), we measured VHS with ASL and maximum OEF (OEFmax) with dynamic susceptibility contrast MRI. Lower OEFmax was uniquely associated with higher WML volume in participants with VHS, indicating a potentially distinct cerebrovascular aging pattern in these individuals.
First in vivo Myocardial Perfusion Measurements using Intra-arterial Spin Labeling during MR-guided Coronary Interventions in Pigs
Authors: Reiss Simon , Waescher Kevin , Lottner Thomas , Özen Ali , Heidt Timo , von zur Mühlen Constantin , Bock Michael
Published: August 2023

Arterial spin labeling (ASL) provides a method for myocardial perfusion quantification without exogenous contrast agents. In MR-guided coronary catheterizations, perfusion measurements can provide a valuable tool to diagnose myocardial perfusion deficits and monitor the success of the intervention. In these interventions, catheters are usually visualized by active receive RF coils attached to the catheter. Using these active coils in transmit mode would enable intra-arterial spin labeling (iASL) in the coronary arteries with an increased labeling efficiency compared to conventional ASL. Here, we show the first in vivo results using iASL for myocardial perfusion measurements during coronary interventions in pigs.
Motion-Corrected 4D-Flow for Neurovascular Applications
Authors: Rivera-Rivera Leonardo , Kecskemeti Steven , Jen Mu-Lan , Miller Zach , Johnson Sterling , Eisenmenger Laura , Johnson Kevin
Published: August 2023

Accurate and precise assessment of neurovascular flow in the brain requires high image fidelity which can be difficult to obtain in populations with high tendencies to move, such as geriatrics and pediatrics. This study presents a 3D radial sampling and multi-scale low rank image reconstruction for self navigated motion correction of 4D-Flow with validations in phantom and invivo studies.
RR-Resolved 5D flow for Decoding the Impact of Cardiac Rhythm on Left Atrial Flow Dynamics in Atrial Fibrillation and Stroke
Authors: Baraboo Justin , Weiss Elizabeth , Pradella Maurice , Ma Liliana , Hwang Julia , Gunasekaran Suvai , Falcão Mariana , Roy Christopher , Stuber Matthias , Passman Rod , Kim Daniel , Markl Michael
Published: August 2023

RR-resolved 5D flow is a novel MRI technique that can acquire time-resolved 3D hemodynamics for varying RR-interval durations during atrial fibrillation (AF) (5D = 3D+cardiac time+RR-interval duration). The purpose of this study was to apply RR-resolved 5D flow MRI in a cohort of AF patients with and without a prior history of stroke. We saw significantly lowered left atrial peak velocities and trends toward higher atrial blood stasis in AF patients with previous stroke history vs no previous stroke history who underwent arrhythmia during MRI acquisition. RR-resolved 5D flow may be a promising approach for cardiovascular imaging in arrhythmic patients.
Improved Agreement of Cerebral Arterial Blood Flow Velocity Measures Using 3D Quantitative QISS MRA
Authors: Koktzoglou Ioannis , Huang Rong , Edelman Robert
Published: August 2023

Quantitative time of flight (qTOF) is a recently described 3D magnetic resonance angiography (MRA) technique for simultaneous luminal and hemodynamic evaluation of the intracranial arteries, that provides higher contrast-to-noise ratio efficiency than 3D phase contrast (PC) MRA and reduces in-plane flow displacement artifacts visible on standard 3D TOF MRA. We hypothesized that the use of a quiescent interval slice-selective-based data acquisition strategy (qQISS) that boosts arterial-to-background contrast might improve the quantitation of intracranial arterial flow velocity. Compared to qTOF MRA, we found that qQISS MRA improved agreement with PC MRA for measuring intracranial blood velocity.
Diffusion-weighted MRI with deep learning for visualizing treatment results of MR-guided HIFU ablation of uterine fibroids.
Authors: Slotman Derk , Bartels Lambertus , Zijlstra Aylene , Verpalen Inez , van Osch Jochen , Nijholt Ingrid , Heijman Edwin , van 't Veer-ten Kate Miranda , de Boer Erwin , van den Hoed Rolf , Froeling Martijn , Boomsma Martijn
Published: August 2023

The non-perfused volume (NPV) cannot be assessed repeatedly with contrast-enhanced imaging during MR-HIFU ablations of uterine fibroids, due to contrast agent dose constraints and safety concerns. In this study, synthetic contrast-enhanced (CE)-T1w scans were generated from diffusion weighted imaging (DWI) using deep learning-based image-to-image translation. A significant linear association was found between the NPV-ratios based on synthetic and paired reference CE-T1w scans (r=0.80, p<0.001). Radiologists agreed in 83% on treatment success based on synthetic and reference CE-T1w scans. This indicates that translation of DWI into synthetic CE-T1w scans has potential as method for gadolinium-free imaging of the NPV.
FieldMapNet MRI: Learning-based mapping from single echo time BOLD fMRI data to fieldmaps with model-based image reconstruction
Authors: Haskell Melissa , Lahiri Anish , Nielsen Jon-Fredrik , Fessler Jeffrey , Noll Douglas
Published: August 2023

Artifacts due to B0 field off-resonance result in image distortions and blurring in non-Cartesian acquisitions. FieldMapNet is a learning-based method to map from each image in a spiral-in BOLD fMRI acquisition to a corresponding B0 fieldmap at that timepoint. We train FieldMapNet in a supervised fashion using custom data acquired at three echo times to generate ground truth dynamic fieldmaps. We then perform a tailored B0 correction at each fMRI timepoint using a model-based image reconstruction (MBIR). We show improved image space RMSE using FieldMapNet vs. a separately acquired GRE fieldmap, and a reduction in distortion artifacts and blurring.
Off-Resonance Self-Correction by Implicit Temporal Encoding: Performance at 7T
Authors: Patzig Franz , Pruessmann Klaas
Published: August 2023

B0-induced distortions are a main caveat for trajectories with long readout durations, particularly at high field. Recently, B0 self-correction based on implicit temporal encoding by the coil array has been proposed and shown to be feasible at 3T. This work focuses on application of the approach at 7T. Performance analysis show that due to the increased strength of B0 inhomogeneities constant density bases to model B0 might not be sufficient. A variable density basis adapting to the gradient is proposed yielding spatially-dependent regularization. By means of this, reconstruction results can be improved demonstrating the feasibility of B0 self-correction at 7T.
Integrating time division multiplexing (TDM) and simultaneous multi-slice (SMS) for accelerating combined diffusion-relaxometry
Authors: Ji Yang , Hoge William , Gagoski Borjan , Westin Carl-Fredrik , Rathi Yogesh , Ning Lipeng
Published: August 2023

We introduce an MRI sequence that integrates the time-division multiplexing (TDM) technique and simultaneous multi-slice (SMS) method to achieve a high slice-acceleration (~6x) factor for acquiring relaxation-diffusion MRI. Two variants of the sequence, i.e., TDM3e-SMS and TDM2s-SMS, were developed to simultaneously acquire slice groups with 3 distinct echo times (TEs) and 2 slice groups with the same TE, respectively. Both sequences were evaluated on a 3T scanner with in-vivo human brains and compared with standard single-band (SB) EPI and SMS-EPI using diffusion measures and tractography results. Results have shown that TDM-SMS provides reliable measures for relaxation-diffusion and standard diffusion MRI.
What Does FEXI Measure?
Authors: Khateri Mohammad , Reisert Marco , Sierra Alejandra , Tohka Jussi , Kiselev Valerij
Published: August 2023

Filter-EXchange Imaging (FEXI) evaluates the permeability of cell membranes, which is already used in clinical research. It relies on suppressing the extracellular signal using strong diffusion weighting (mobility filter causing a reduction in the overall diffusivity) and monitoring the subsequent diffusivity recovery. Using simulations, we demonstrate the presence of a spurious exchange: In compartments with complex geometry, there are locations where spins remain unaffected by the mobility filter. Moving to other locations afterward contributes to the diffusivity recovery, thus mimicking exchange. The discovered phenomenon opens large room for investigation towards characterizing the compartment geometry and crystallizing the genuine membrane permeation.
Evaluation of Single-shot EPI with Sub-millimeter Resolution fMRI on the Next-Generation 7T brain scanner.
Authors: Beckett Alexander , Vu An , Ahn Sinyeob , Torrisi Salvatore , Polimeni Jonathan , Yacoub Essa , Setsampop Kawin , Bilgic Berkin , Gunamony Shajan , Potthast Andreas , Dietz Peter , Chang Yulin , Feinberg David
Published: August 2023

The newly developed “Impulse” head gradient (200 mT/m Gmax, 900 T/m/s) on the NexGen 7T scanner has been specifically designed to allow for high-resolution single-shot EPI with minimal distortions and blurring by minimizing echo spacing. In conjunction with the increased SNR and reduced g-factor noise afforded by the 96 channel receive array coil, mesoscale fMRI at 0.45mm and 0.6mm isotropic resolutions can be robustly achieved in human subjects.
Spin-echo line-scanning at 7T
Authors: Raimondo Luisa , Knapen Tomas , Dumoulin Serge , van der Zwaag Wietske , Siero Jeroen
Published: August 2023

We implemented spin-echo line-scanning (SELINE) fMRI through a simple rotation of the spin-echo refocusing gradient to a plane perpendicular to the excited slice and removing the phase encode gradient. This technique promises a combination of high spatio-temporal resolution and specificity of functional responses to the microvasculature. We compared SELINE data to the corresponding gradient-echo version (GELINE). We demonstrate that SELINE showed much improved line selection compared to GELINE, albeit at the cost of a significant drop in functional sensitivity. The low functional sensitivity needs to be addressed before SELINE can be applied.
Towards whole brain layer-fMRI connectivity: methodological advancements for functional layer connectomics
Authors: Koiso Kenshu , Dresbash Sebastian , Wiggins Christopher , Gulban Omer , Miyawaki Yoichi , Poser Benedikt , Huber Renzo
Published: August 2023

Laminar-specific fMRI allows neuroscientists to address research questions of directional functional connectivity within and across brain areas. While recent sequence developments allow improvements in coverage and mitigations of venous biases, previous attempts of whole-brain connectome datasets turned out to be too artifact-dominated (Mueller 2021) to be neuroscientifically applicable. Here we present a new and improved sequence used for acquiring a relatively large open dataset of whole-brain laminar connectivity. Its purpose is to:

investigate the reproducibility of laminar connectivity results,

to benchmark and develop processing pipelines,

and to explore which type of new neuroscientific research questions become addressable with laminar fMRI.
Investigating structural and functional connectivity of human entorhinal subregions using DTI and fMRI
Authors: Syversen Ingrid , Reznik Daniel , Schröder Tobias Navarro , Doeller Christian
Published: August 2023

Despite previous attempts to localize the human homologues of the medial (MEC) and lateral entorhinal cortex (LEC) using fMRI and DTI separately, there are still uncertainties related to the choice of imaging modality and seed regions used. In this study, we investigated both structural connectivity from DTI and functional connectivity from fMRI between the EC and associated brain regions. Differential EC connectivity to these regions was then used to predict the locations of the human homologues of MEC and LEC. Our results from both DTI and fMRI showed a qualitatively similar subdivision into posteromedial and anterolateral EC, supporting previous studies.
Time-delay processing of cerebrovascular reactivity reveals pre-surgical indicators of revascularization response in adults with moyamoya
Authors: Waddle Spencer , Garza Maria , Davis Larry , Chitale Rohan , Fusco Matthew , Lee Chelsea , Patel Niral , Jordan Lori , Donahue Manus
Published: August 2023

The goal of this work is to apply time-regression analysis to hypercapnic reactivity data in an interventional trial to identify pre-surgical indicators of treatment response in moyamoya vasculopathy patients. We hypothesized that pre-surgical posterior flow-territory reactivity, including greater cerebrovascular reactivity and reduced vascular delay time, portend collateralization success. In 41 participants evaluated pre and 1-year post-operatively, pre-surgical posterior flow-territory maximum reactivity was higher (p=0.02) in patients with good vs. poor angiographic outcomes. This highlights that topographical features of preserved cerebral auto-regulation may contribute to neoangiogenic potential, and importantly, that reactivity mapping may provide a diagnostic tool for informing surgical candicacy.
Fusion of T2/FLAIR Hyperintensities with Chemical Shift Imaging in Glioma Patients
Authors: Zhao Wufan , Coello Eduardo , Liao Vicky , Tal Assaf , Lin Alexander
Published: August 2023

This work fuses manual segmentation of T2/FLAIR hyperintensity regions using 3D Slicer with multivoxel magnetic resonance spectroscopy (MRSI), which profiles neurochemical concentrations in a wide area of the brain. The utility of MRSI is demonstrated in the mapping of metabolites including 2HG, N-acetyl aspartate, myoinositol, glutamate plus glutamine, lactate, and choline in the region of interest. Voxel fractions of hyperintensity were correlated to metabolites, and metabolite-to-creatine ratio intercepts were used to compare hyperintense with healthy tissue.
An Alternative to WEX: T1-Independent Exchange Rate Quantification using Phase Sensitive Water Exchange Spectroscopy
Authors: Plaehn Nils , Mayer Simon , Albertová Petra , Jakob Peter , Gutjahr Fabian
Published: August 2023

Water Exchange Spectroscopy (WEX) is one of the most widely used approaches to assess the exchange rate of labile protons from a solute to water. In this work, we propose as an versatile alternative “Phase Sensitive WEX” (PS-WEX), which uses an additional RF-pulse and a fixed mixing-time delay. By exploiting the phase sensitivity of the PS-WEX pathway the dynamic range can be increased and the T1-dependence of the signal is completely reduced. This is demonstrated in simulations and phantom measurements. The fixed mixing-time reduces the influence of the T1-decay on the signal curve leading to improved fit quality.
Motion2Recon: A Motion-Robust Semi-Supervised Framework for MR Reconstruction
Authors: Beg Harris , Gunel Beliz , Ozturkler Batu , Sandino Christopher , Pauly John , Vasanawala Shreyas , Chaudhari Akshay , Desai Arjun
Published: August 2023

In this study, we propose Motion2Recon, a semi-supervised consistency-based approach for robust accelerated MR reconstruction of motion-corrupted images. Motion2Recon reduced dependence on fully-sampled (supervised) training data and improves reconstruction performance among motion-corrupted scans. It also maintained superior performance among non-motion, in-distribution scans, which may help eliminate the need for manual motion detection. All code and experimental configurations are openly available in Meddlr (https://github.com/ad12/meddlr).
Comparison of Self-Supervised Image Reconstruction Methods for Undersampled Image Reconstruction: Validation in a Realistic Setting
Authors: Yu Thomas , Hilbert Tom , Piredda Gian Franco , Canales-Rodrıguez Erick , Kober Tobias , Thiran Jean-Philippe
Published: August 2023

Self-supervised reconstruction methods for undersampled acquisitions are becoming increasingly used. We compare different self-supervised reconstruction methods using fully sampled and prospectively/retrospectively accelerated data; we find that prospective and retrospective reconstructions can differ significantly in quantitative metrics and perceptual quality. To test the methods’ generalizability, prospectively accelerated data from multiple field strengths is reconstructed without retraining/retuning. We find that no-reference image quality metrics can distinguish state of the art methods from the baseline, albeit with ambiguity between the state of the art methods.
Assessing potential correlation between T2 relaxation and diffusion of brain lactate
Authors: MOUGEL Eloïse , Malaquin Sophie , Valette Julien
Published: August 2023

Little or no correlation exists between diffusion and T2 relaxation of intracellular brain metabolites, as measured by MRS. However, for lactate, which is both intracellular and extracellular, some correlation might exist, which would be crucial to interpret lactate diffusion. Using a frequency-selective diffusion-weighted (DW) MRS sequence that removes J-modulation on the lactate peak at 1.3 ppm, thus preserving lactate signal even at long TE, we investigated the effect of echo time TE on lactate diffusion-weighted attenuation, for TE between 50.9 and 110.9 ms. It appears that the effect of TE on the apparent diffusivity and kurtosis is negligible.
Automatic Segmentation of the Great Arteries for Robust Hemodynamic Assessment
Authors: Montalt-Tordera Javier , Pajaziti Endrit , Jones Rod , Steeden Jennifer , Schievano Silvia , Muthurangu Vivek
Published: August 2023

Computational fluid dynamics (CFD) are useful in the assessment of blood flow conditions in patients with congenital heart disease. A necessary, time-consuming step in the creation of CFD models is the segmentation of the anatomy of interest. In this work, a neural network was trained to segment the aorta and the pulmonary arteries in 3D MRI, and its performance was evaluated in the context of a CFD application. The network performs well in terms of Dice score and is shown to lead to accurate pressure and flow velocity fields, with errors at the level of inter-observer variability.
T1ρ can detect microstructural changes in cartilage induced by conservative interventions: a one-year randomized controlled trial
Authors: Mazzoli Valentina , Uhlrich Scott , Kogan Feliks , Silder Amy , Finlay Andrea , Delp Scott , Beaupre Gary , Kolesar Julie , Gold Garry
Published: August 2023

We performed a single-blind randomized clinical trial in subjects with medial knee OA to evaluate the effect of a gait modification. Primary outcomes were pain and KAM (surrogate measure of medial knee loading). We also utilized cartilage T2 and T1ρ to assess (micro)structural changes induced by the treatment. In the Intervention group, we observed a greater reduction in pain and KAM (reduced loading), and less increase in T1ρ in the medial femoral compartment, potentially indicating slowed cartilage degeneration. Our study shows that quantitative cartilage MRI is a promising outcome measure in clinical trial assessing non-surgical treatment for knee OA.
Bi-exponential UTE-T2* Evaluation of Longitudinal Changes in Knee Cartilage Over 2 Years Following Anterior Cruciate Ligament Reconstruction
Authors: Williams Ashley , Qian Yongxian , Chu Constance
Published: August 2023

This work evaluates mono- and bi-exponential UTE-T2* relaxation in 6 tread mark regions of knee cartilage of 18 participants with ACL-injury prior to reconstruction surgery and in 15/18 participants 2 years after surgery. Bi-exponential T2*short had a smaller fractional contribution than T2*long in all regions examined. However, T2*short accounted for a higher fraction of total signal in deep cartilage layers compared to superficial. While both mono- and bi-exponential UTE-T2* analyses showed significant longitudinal changes, bi-exponential analyses did not exceed the sensitivity of mono-exponential UTE-T2* for detection of knee cartilage compositional changes over the first two years following ACL reconstruction.
Diagnostic Performance of Diffusion Weighted Imaging, Arterial Spin Labeling and Amide Proton Transfer in sub-classifications of gliomas
Authors: Xiong DiaoHan , Wang Rui , Wen Tao , Gan TieJun , Wang PengFei , Ren XinYing , Li YuJing , Zhang Jing , Ai Kai
Published: August 2023

To assess the diagnostic performance of Amide Proton Transfer (APT) and Arterial Spin Labeling (ASL) for distinguishing different sub-classifications of gliomas in comparison with Diffusion Weighted Imaging (DWI). Forty patients underwent sequences including T1W enhancement, DWI, APT and 3D-pCASL. ADCmean, ADCmean-to-ADCNAWM ratio, APTmean, APTmean-to-APTNAWM ratio, regional cerebral blood flow (rCBF) and rCBFmean-to-rCBFNAWM ratio are calculated. The results showed that diagnostic accuracy of APTmean was superior in distinguishing sub-classifications of gliomas than other parameters. We concluded that APT can be used in predicting sub-classification of gliomas based on WHO CNS5, providing more valuable supplementary information for early treatment guidance and surgery.
Spatiotemporal dynamics of anterograde and retrograde neurodegeneration following spinal cord injury
Authors: Schading Simon , David Gergely , Emmenegger Tim , Achim Cristian , Curt Armin , Freund Patrick
Published: August 2023

We tracked remote neurodegenerative changes in the cervical cord following spinal cord injury over 2 years using macrostructural readouts (cross-sectional area, left-right width, anterior-posterior width) derived from T1-weighted MPRAGE images. Thereby, we evaluated the dependency of the magnitude of atrophy on the distance to the lesion. Over time, differences in atrophy rates along the cervical cord rostral to the lesion gradually formed a lesion gradient. Using anterior-posterior width and left-right width as surrogates for investigating anterograde and retrograde degeneration separately, our results suggest that these two types exhibit different spatiotemporal dynamics. A lesion gradient was only observable for retrograde degeneration.
Corpus callosum lesions are associated with worse cognitive performance in cerebral amyloid angiopathy
Authors: Freeze Whitney , Zotin Maria Clara Zanon , Scherlek Ashley , Perosa Valentina , Warren Andrew , van der Weerd Louise , Marcotte Dorothee Schoemaker , Horn Mitchell , Gurol Edip , Gokcal Elif , Bacskai Brian , Viswanathan Anand , Greenberg Steven , Reijmer Yael , van Veluw Susanne
Published: August 2023

We assessed the contribution of small vessel disease lesions in the corpus callosum (CC) to vascular cognitive impairment in cerebral amyloid angiopathy (CAA). A total number of 21 CC lesions was found in 19/65 (29%) CAA patients. CC lesion presence was associated with reduced microstructural white matter integrity within the CC and in the whole brain white matter. Patients with CC lesions performed significantly worse on multiple cognitive domains compared to those without CC lesions after correcting for relevant covariates. Together, our findings suggest that CC lesions independently contribute to cognitive impairment through strategic microstructural disruption of white matter tracts.
Sub-0.1 microliter CBV fMRI on the Next Generation 7T scanner
Authors: Feinberg David , Torrisi Salvatore , Beckett Alexander , Stirnberg Rüdiger , Stöcker Tony , Ehses Philipp , Huber Renzo
Published: August 2023

Laminar-specific fMRI with CBV-sensitive VASO can address neuroscience research questions on directional information processing within and across brain areas. However, conventional 0.8mm resolutions cannot Nyquist sample the individual layer-groups of interest (e.g. Layers II/III from layer IVc in V1). Here we implement, evaluate, and apply a 0.39-0.45mm (iso.) VASO protocol on the NextGen 7T scanner to resolve layer-features that could not be resolved in humans before. We find that 0.45 mm protocols are possible if the sequence parameters of EPI-segmentation and GRAPPA acceleration are differently optimized than one would do for conventional fMRI protocols.
Deep Learning Methods for Reversible Cerebral Vasoconstriction Syndrome Classification Based on Resting-state fMRI Images
Authors: Hsu Tun-Wei , Wu Chia-Hung , Wu Hsiu-Mei , Lai Kuan-Lin , Chen Shih-Pin , Wang Shuu-Jiun , Liring Jiing-Feng , Guo Wan-Yuo
Published: August 2023

Reversible cerebral vasoconstriction syndrome (RCVS) is a reversible segmental and multifocal vasoconstriction of the cerebral arteries and is believed to relate to autonomic network over-activity. We used Long Short-Term Memory networks (LSTMs), a type of deep neural network designed to handle time sequence data, to learn directly from the rs-fMRI time-series for classification of individuals with RCVS and healthy controls based on the regions in autonomic and other functional networks. These results provide methodological implications for rs-fMRI data of RCVS patients involved in the analysis and are a key element in future studies.
Title Fractal Analysis of the BOLD Signal in Preterm Infants Scanned Shortly After Birth and at Term-Equivalent Age
Authors: Weber Alexander , Drayne Johann , Campbell Olivia , Chau Cecil , Miller Steven , Grunau Ruth
Published: August 2023

It has been found that fractal analysis of the BOLD signal in fMRI can be used to measure brain functioning, development, and health. There has to our knowledge, however, not been any fractal analysis fMRI studies done in newborns. By computing the mean Hurst exponent in 9 resting state networks and in a grey matter mask. We found the largest increase in the Hurst exponent between pre-term and term equivalent aged subjects was in the motor and visual network. This motivates the need of further exploration of fractal analysis as a measure of brain dynamics in pre-term infants.
Skeletal muscle acetylcarnitine during submaximal exercise and recovery: Interleaved 1H/31P MRS 7T pilot study
Authors: Klepochová Radka , Niess Fabian , Meyerspeer Martin , Trattnig Siegfried , Krebs Michael , Kautzky-Willer Alexandra , Leutner Michael , Krššák Martin
Published: August 2023

The study aimed to explore the behavior of skeletal muscle acetylcarnitine and phosphocreatine during submaximal plantar flexion exercise using interleaved 1H/31P MRS at 7T. Acetylcarnitine decreased to steady state during the exercise, increased back to initial levels in early recovery period and started to decline during later phase of recovery. Studies including more volunteers and patients with broader range of metabolic conditions and physical fitness will be necessary for detailed quantitative analysis.
A Neural Network Application for Fast Simultaneous Muscle T2-Water and Fat Fraction Mapping from Multi-Spin-Echo Acquisitions
Authors: Barbieri Marco , Hooijmans Melissa , Gold Garry , Kogan Feliks , Mazzoli Valentina
Published: August 2023

Muscle T2 relaxometry can be used to monitor disease activity in neuromuscular disorders. Dictionary matching of multi-echo-spin-echo (MESE) data is the gold-standard method to estimate the T2 of the myocitic component (T2-water) because of its ability to correct for multiple confounding factors, but suffers from a high computational burden. This work proposes a neural network (NN) approach for fast muscle T2-water mapping with subject-specific T2-fat calibration to overcome computational limitations of the dictionary method. The method was validated in-vivo against the standard dictionary approach. The NN application outperformed the dictionary approach in computational resources (x140 faster) while retaining quantitative accuracy.
Mapping the time course of cortical reorganization and the influence of visual experience during plasticity.
Authors: Carvalho Joana , Fernandes Francisca , Shemesh Noam
Published: August 2023

During development, the organization of the brain’s underlying circuitry is shaped by sensory experience. However, how the adult brain reorganizes remains much less understood. Here, we performed a longitudinal BOLD-fMRI study assessing plasticity in the adult rat brain using a chronic visual deprivation model and a novel set-up for mapping detailed visual responses. We show that dark rearing (DR) boosts neural responses to visual stimuli but delays retinotopic and spatial frequency (SF) specialization in the visual pathway. Our findings suggest that DR shifts the stability/plasticity balance and that fMRI can map dynamic processes in the visual system.
Insights into Communicating Congenital Hydrocephalus on Neurodevelopment in a Mouse Model of Ciliopathy
Authors: Wu Yijen , Stapleton Margaret , Panigrahy Ashok , Lo Cecilia
Published: August 2023

Mice homozygous to the partial loss-of-function Dnah5 allele, a component in the ependymal motile cilia, developed congenital hydrocephalus. Volumetric analysis showed enlarged aqueduct, indicating that the hydrocephalus was not caused by collapsed aqueduct, but rather by altered cerebrospinal fluid homeostasis. Furthermore, specific brain regions displayed dysplasia, including hippocampus, olfactory bulb and cerebellum. Diffusion tractography followed by topology analysis showed altered neuronal network organization in these brain areas. Our study suggests that ependymal cilia may play a crucial role in grey matter and white matter development and neuronal network organization.
Longitudinal simultaneous cortex wide Ca2+ imaging and whole brain functional magnetic resonance imaging in awake mice across the lifespan
Authors: Mandino Francesca , Shen Xilin , O'Connor David , Mukherjee Bandhan , DeLuca Kristin , Owens Ashley , Qu An , Onofrey John , Papademetris Xenophon , Strittmatter Stephen , Lake Evelyn
Published: August 2023

There is a clear need for imaging protocols in awake animals. Yet, there are only a few approaches in mice, despite their usefulness as translational research subjects. We introduce the first protocol for longitudinal simultaneous fMRI and Ca2+ imaging in awake mice. The same animals are imaged four times (from 4 to 12 months of age) – twice under anesthesia, and twice awake. Our framework includes two acclimation protocols: an initial intensive training followed by a ‘refresher' course. We find a marked improvement in motion between the two awake sessions. Implications for future dual-imaging experiments in awake mice are considered.
Impaired brain perfusion and cerebrovascular reactivity in the zQ175 mouse model of Huntington’s Disease, a longitudinal pCASL-MRI study
Authors: Vasilkovska Tamara , Vanreusel Verdi , Salajeghe Somaie , van Audekerke Johan , Hirschler Lydiane , Pustina Dorian , Cachope Roger , Tang Haiying , Liu Longbin , Dominguez Celia , Munoz-Sanjuan Ignacio , Van der Linden Annemie , Verhoye Marleen
Published: August 2023

Abnormal cerebral vasculature and consequent diminished cerebrovascular function have been shown to play a role in Huntington’s Disease (HD). However, how these impairments reflect on cerebral blood flow (CBF) dynamics and vascular reactivity (CVR) have been poorly understood. Towards this, we performed a longitudinal study measuring CBF and CVR, using pCASL, in the zQ175 KI Huntington’s disease (HD) mouse model at pre-manifest (3/4.5 months), disease onset (6 months) and manifest (9 months) stage. Our results demonstrate decreased CBF under CO2 challenge at disease onset and decreased CVR in manifest HD stage in the zQ175 KI mice compared to age-matched controls.
A coil-based approach to accelerate the FLIP spatial lipid removal algorithm in 3D EPSI.
Authors: Adany Peter , Choi In-Young , Lee Phil
Published: August 2023

We have recently developed the spatial domain, Fast LIpid signal Processing (FLIP) algorithm to remove subcutaneous lipid signals in MRSI. Practical application of FLIP to 3D EPSI was challenging due to the need for long processing times. We present an updated algorithm, named FLIP-COIL, which significantly reduces the processing times utilizing receive coil senstivity profiles. Algorithms including FLIP, FLIP-COIL, as well as PGA, HSVD and L2 are compared in 3D EPSI of ten subjects. This study demostrates that the FLIP-COIL approach can drastically reduce processing time with favorable performance of lipid removal in 3D EPSI over existing other algorithms.
Complex fitting of 1H-MR spectra improves quantification precision independent of SNR and noise correlation
Authors: Campos Leonardo , Swanberg Kelley , Gajdošík Martin , Landheer Karl , Juchem Christoph
Published: August 2023

Quantification of in vivo proton magnetic resonance spectra (1H-MRS) still commonly involves evaluation of exclusively the real part of acquired spectral signals, but ignoring the information contained in the imaginary component may limit precise identification of individual metabolite contributions. Here, we assess quantification precision relative to SNR and noise correlation for both real and complex linear combination model fits of simulated 1H-MRS spectra reflecting brain metabolite concentrations and T2. Extending our results to inclusion of measured in vivo baselines, we demonstrate consistent improvements in metabolite quantification precision and/or accuracy by complex relative to real fits.
Fast inline reconstruction of T2 maps from dual echo spin echo images
Authors: Snyder Jeff , Seres Peter , Stobbe Robert , Grenier Justin , Smyth Penelope , Blevins Gregg , Wilman Alan
Published: August 2023

A fast reconstruction method for PD-T2w T2 maps is presented and compared to the previous L2 norm minimization technique using Bland-Altman analysis in a five patient multiple sclerosis data set acquired at 3 T. The new (subtraction) technique was in excellent agreement with the L2 norm method (confidence intervals of -1.1 to +1.2 ms), with average single slice reconstruction times of 0.6 s compared to 134 s. The speed of T2 map production allowed accurate (based on sequence simulation via Bloch equations) inline T2 maps directly on the MRI console.
Anisotropic Mechanical Properties of White Matter Tracts in Aging via Transversely Isotropic MR Elastography
Authors: Caban-Rivera Diego , Smith Daniel , McGarry Matthew , Williams L. Tyler , McIlvain Grace , Van Houten Elijah , Paulsen Keith , Bayly Phil , Johnson Curtis
Published: August 2023

This study combined multi-excitation MR Elastography (ME-MRE) with a transversely isotropic inversion nonlinear inversion algorithm and diffusion tensor imaging (DTI) fiber directions to investigate anisotropic white matter tract integrity in aging. Participants were 5 older adults and 17 young adults. MRE outcomes include substrate shear modulus, μ, shear anisotropy, φ, tensile anisotropy, ζ, and DTI measures were also examined. Shear and tensile anisotropies were significantly different in the Corona Radiata and Superior Longitudinal Fasciculus. Diffusion measures were significantly different between groups in most tracts. These results suggest sensitivity of anisotropic properties to biological changes along white matter tracts in aging.
MR Elastography of the Frontal Cortex: Impact of Aging and Regional Differences
Authors: Twohy Kyra , Delgorio Peyton , Diano Alexa , Kramer Mary , Merritt Alexis , McIlvain Grace , Hiscox Lucy , Johnson Curtis
Published: August 2023

This study tested the utility of high-resolution magnetic resonance elastography (MRE) to analyze frontal cortex degradation due to advancing age. Brain tissue stiffness significantly varied in frontal cortex regions and frontal cortex stiffness also significantly decreased with age. A significant interaction between age and region was found, indicating regions changed differently with age. The stiffness of all frontal cortex regions degraded more per year than reported whole frontal lobe stiffness loss, indicating greater loss in the cortex with age. This approach brings potentially increased sensitivity and specificity to the structure-function relationship found in the frontal cortex with age.
Performance of Proton Density Fat Fraction, MRE-based Liver Stiffness, and T1 in Identifying NASH Patients at High Risk of Disease Progression
Authors: Li Jiahui , Lu Xin , Zhu Zheng , Kalutkiewicz Kyle , Mounajjed Taofic , Sui Yi , Glaser Kevin , Hoodeshenas Safa , Venkatesh Sudhakar , Manduca Armando , Shah Vijay , Ehman Richard , Allen Alina , Yin Meng
Published: August 2023

Multiparametric MRI/MRE and liver biopsy were performed in 104 patients at risk for NASH. We correlated measurements of proton density fat fraction (PDFF), 3D vector MRE-assessed liver stiffness (LS), and T1 relaxation time across histological features of NASH. We found that PDFF showed superior diagnostic performance in identifying patients with NASH (AUC: 0.84 [0.76, 0.92]), while LS showed superior diagnostic performance in stratifying NASH patients at high risk (0.85 [0.75, 0.94]). The results showed that T1 measurement, either alone or in combination with other biomarkers, did not perform as well as PDFF and LS in diagnosing NASH or stratifying high-risk NASH.
In-vivo Absolute Multinuclear Thermometry (AMT) in a Rat Model
Authors: Yaghmazadeh Omid , Voroslakos Mihaly , Mattingly Mark , Gironda Zakia , Wadghiri Youssef , Dehkharghani Seena , Alon Leeor
Published: August 2023

We introduce an in-vivo multinuclear MR thermometry technique which utilizes the unique frequency shift between water and sodium resonant frequencies. Reconstruction of the absolute temperature is validated using chemical shift imaging conducted on a rodent model implanted with a thin fiber optic probe for monitoring.