bluuebunny/crossref_metadata_2025 huggingface dataset:
T1ρ Dispersion in White Matter Correlates with Quantitative Metrics of Cognitive Impairment
Authors: Adelnia Fatemeh , Davis Taylor , Acosta Lealani Mae , Puckett Amanda , Wang Feng , Zu Zhongliang , Harkins Kevin , Gore John
Published: August 2023

R1ρ dispersion at weak locking fields (R1ρDiff) has the potential to reveal information on microvascular geometry and density. Our results show ΔR1ρ of white matter extracted from R1ρDiff dispersion is significantly greater in subjects with lower RBANS and MoCA scores. R2 or R1p values measured at a single locking field amplitude have no significant correlation with cognitive impairment scores. This work supports the hypothesis that microvascular impairment in white matter may be one of the causal factors in the progression of cognitive impairment in older adults.
Sex-differences in CBF changes as a biomarker of preclinical MCI
Authors: Sanami Safa , Intzandt Brittany , Huck Julia , Group PREVENT-AD Research , Gauthier Claudine
Published: August 2023

Alzheimer’s Disease (AD) is the most common form of dementia, preceded by a mild cognitive impairment (MCI) prodromal stage. There are sex differences in the prevalence and severity of MCI and AD. However, the presence of sex differences in cerebral hemodynamics during the transition from normal cognition to MCI is unknown. This is the first study to assess whether sex differences exist in cerebral blood flow (CBF) in the years prior to MCI diagnosis in patients with a familial history of AD.
Post-traumatic stress disorder may affect the progression of cognitive impairment in World Trade Center responders
Authors: Zhou Juin , Kritikos Minos , Huang Chuan , Clouston Sean , Lucchini Roberto , Gandy Samuel , Luft Benjamin , Bromet Evelyn
Published: August 2023

A larger than expected number of World Trade Center (WTC) responders, now at midlife, are experiencing chronic post-traumatic stress disorder (PTSD) and incidence of mild cognitive impairment (MCI). A previous study reported that WTC responders with MCI have altered white matter connectivity when compared to unimpaired responders. However, the effects of PTSD on fiber integrity in this population was not studied due to a limited sample size. In the present study, we analyzed 97 WTC responders with/without CI and/or PTSD. Our results suggest that PTSD may influence the neuropathology of CI within this population.
Multivariate quantification of brain differences in individuals with family history of Alzheimer's disease and APOE4 genetic risk
Authors: Tremblay Stefanie , Spreng Nathan , Pirhadi Amir , Huck Julia , Tardif Christine , Chakravarty Mallar , Group PREVENT-AD Research , Villeneuve Sylvia , Leppert Ilana , Carbonell Felix , Iturria-Medina Yasser , Steele Christopher , Gauthier Claudine
Published: August 2023

Although the APOE4 genotype is known to increase the risk of developing Alzheimer’s disease (AD), the mechanisms through which this occurs are not fully understood. Here, we used a voxel-wise multivariate approach, the Mahalanobis distance (MhD), to quantify the extent to which the white matter microstructure of individuals with the APOE4 genotype differ from those without the E4 allele. The MhD of individuals with the E4 allele deviated significantly from our reference group in several regions, including tracts projecting to the hippocampus, a region known for its involvement in AD. Future work will investigate links with cognition and lifestyle factors.
Contrast-free 3D Cartesian MRA of the thoracic aorta in 3 min: preliminary clinical evaluation
Authors: Fotaki Anastasia , Munoz Camila , Hua Alina , Emmanuel Yaso , Kunze Karl , Neji Radhouene , Masci Pier , Botnar René , Prieto Claudia
Published: August 2023

Cardiovascular Magnetic Resonance Angiography is established for serial monitoring of thoracic aortic disease. Limitations of the current approach include the diaphragmatic navigation, leading to long acquisition times and the correction of the aortic motion, solely in one direction. We propose a T2-prep bSSFP sequence that incorporates image-based navigation and inline non-rigid motion-correction for efficient, free-breathing and isotropic aortic imaging. Comparison between the conventional and the research sequence shows similar diagnostic confidence with both techniques in much shorter acquisition time [3.11.1min (iNAV) versus 11.5 min3.4 (dNAV),P<0.0001] and good agreement of aortic measurements between both techniques, holding promise for forthcoming clinical adoption.
Comparison of Interpolation Methods for Ex-vivo and In-vivo Cardiac Diffusion Tensor Imaging
Authors: Stimm Johanna , Kozerke Sebastian , Stoeck Christian
Published: August 2023

To address the challenge of low resolution and limited number of slices in in-vivo cDTI, and the need for 3D structural information in image-based modeling, we compare five interpolation techniques of predominant cardiomyocyte orientation: two low-rank models, one rule-based method and two tensor interpolation approaches. The direct tensor interpolation approaches result in the smallest errors, followed by the low-rank models and the rule-based method. In view of an optimal experimental design in-vivo, the ex-vivo experiments suggest a larger benefit of increasing in-plane resolution rather than SNR, and a non-linear increase in error for less than five short-axis slices.
A comparison of oxygenation-sensitive cardiac MRI methods after hyperventilation
Authors: Huang Qi , Mendes Jason , Adluru Ganesh , DiBella Edward
Published: August 2023

Here we study SSFP-based OS-CMR and EPI-based T2*/T2 methods for detection of myocardial oxygenation changes. These techniques have been used previously, and OS-CMR has been investigated in many studies. However, quantifying T2* and T2 every heartbeat may add information to the semi-quantitative OS-CMR method. Here a limited study of subjects on a 3T scanner is performed. Preliminary quantitative results including comparisons between the methods are shown.
Evaluation of non-contrast free-breathing compressed SENSE T1-TFE cardiac MRI at 3T in young children with congenital heart diseases
Authors: Ristow Inka , Zhang Shuo , Hancken Caroline-Viktoria , Stark Maria , Rickers Carsten , Katemann Christoph , Bannas Peter , Adam Gerhard , Herrmann Jochen , Well Lennart , Weinrich Julius
Published: August 2023

High-quality cardiac MRI at 3T in sedated children with congenital heart disease (CHD) is challenging, because of field inhomogeneities and free breathing motions. Therefore, we aimed to employ the non-contrast free-breathing generic T1-weighted turbo-field echo (TFE) sequence with compressed sensing reconstruction for assessment of vessel diameters and evaluation of the intra- and extracardiac structures in children with CHD aged <5 years. Our results show a highly reliable clinical applicability for intra- and extracardiac structures with significantly higher accuracy in comparison to contrast-enhanced MR-angiography and 3D-Dixon sequences.
Radiofrequency Array Concepts for Cardiac MRI at 10.5 T and 14.0 T: Does an Increased Channel Count Really Help?
Authors: Eigentler Thomas , Nurzed Bilguuun , Kuehne Andre , Niendorf Thoralf
Published: August 2023

The gain in signal-to-noise ratio is driving the ultrahigh field and extreme field MRI. This work highlights the opportunities and electromagnetic constraints of realistic radiofrequency array concepts tailored for cardiovascular MRI at 7.0T, 10.5T, and 14.0T. For this purpose electromagnetic field simulations were performed using 32, 48 and 64-channel RF transceiver array configurations at 7.0T, 10.5T, and 14.0T. Our findings demonstrate, that a higher channel count increases the degrees of freedom of B1+ shaping. Furthermore, the preliminary results provide a strong mandate for static PTX or even dynamic PTX tailored at the heart at 10.5T and 14.0T.
Preliminary Clinical Validation of Non-rigid Motion-compensated 3D Whole-heart T2 mapping in a hybrid PET-MR system
Authors: Schneider Alina , Munoz Camila , Hua Alina , Kunze Karl P , Neji Radhouene , Ismail Tevfik F , Botnar René M , Prieto Claudia
Published: August 2023

Simultaneous 18F-FDG PET-MRI has shown promise for improved diagnostic accuracy of inflammatory cardiac diseases. However, respiratory motion and mis-registration between free-breathing 3D PET and 2D breath-held MR images remain challenges that have hindered its clinical adoption. We have recently proposed a free-breathing non-rigid motion-compensated 3D whole-heart T2-mapping that enables detection of myocardial inflammation and provides non-rigid respiratory motion fields to correct simultaneously acquired PET data in a 3T PET-MR system. Here, we perform a preliminary clinical validation of this approach in 8 patients with suspected cardiovascular disease. Good image quality with T2 values comparable to clinical 2D T2-mapping was achieved.
Deep learning voxelwise classification of primary central nervous system lymphoma using DSC-PWI normalized time-intensity curves
Authors: Garcia-Ruiz Alonso , Pons-Escoda Albert , Grussu Francesco , Naval-Baudin Pablo , Monreal Camilo , Lopez-Rueda Antonio , Oleaga Laura , Majos Carlos , Perez-Lopez Raquel
Published: August 2023

The robustness and accuracy of current MR methods to differentiate brain tumours is limited. In this study we investigate the potential of dynamic susceptibility perfusion-weighted imaging (DSC-PWI) normalized time-intensity-curves (nTIC) to support lymphoma diagnosis by harnessing voxelwise and temporal information to train a convolutional neural network (CNN). This novel approach discriminated patients with lymphoma from glioblastoma and metastasis with an average accuracy of 0.94, using only a limited number of patients for training, outperforming standard DSC-PWI measurements. Furthermore, it provides voxel-by-voxel lymphoma probability maps to further help visual diagnosis of neuroradiologists.
To what extent is DSC-MRI able to detect subtle blood-brain barrier leakage in cerebral small-vessel disease?
Authors: Elschot Elles , Backes Walter , de Jong Joost , Drenthen Gerhard , Wong Sau May , Staals Julie , van Oostenbrugge Robert , Rouhl Rob , Jansen Jacobus
Published: August 2023

This study investigated to what extent blood-brain barrier (BBB) leakage (1) can be measured with DSC-MRI and (2) is influenced by perfusion. In vivo DCE (golden-standard) and DSC data of patients with cerebral small vessel disease (cSVD) and elderly controls were used, as well as simulations of signal curves. DSC-MRI, in contrast to DCE-MRI, is not sensitive enough to measure subtle leakage in cSVD. Further research is required to better disentangle perfusion effects from leakage, and therefore correction methods should be used with caution for measuring subtle leakage.
Combining DCE and DSC-MRI in Arterial Input Function Estimation Using Multi-Channel Blind Deconvolution
Authors: Macicek Ondrej , Jirik Radovan , Latta Peter , jr. Zenon Starcuk
Published: August 2023

We propose to combine DCE and DSC-MRI in a simultaneous acquisition and processing scheme to provide more information for estimation of the arterial input function using multi-channel blind deconvolution. On simulated and flow-phantom data, we show that DCE-DSC blind deconvolution is superior to standard DCE blind deconvolution, especially for low signal-to-noise-ratio conditions.
How much earlier did MRI detect breast cancer than mammography in the DENSE trial?
Authors: Cover Keith S
Published: August 2023

The current analysis found MRI screening in the DENSE trial detected invasive breast cancers about 6 years earlier than mammography. The calculation is based on first and second round invasive cancer detection rates. The 6 years is also consistent with the trial’s high false positive rate in the second round that used “prior” first round exams to estimate lesion growth over the 2 years between rounds. The “how much earlier” measure provides an additional means for comparing the relative performance of breast cancer screening modalities.
2D iDQC-MRS suggests that bone marrow fatty acids are more saturated for postmenopausal osteoporosis
Authors: Bao Jianfeng , Wang Xiao , Zhang Yong , Cheng Jingliang
Published: August 2023

Postmenopausal osteoporosis (PMOP) in the female elderly population has become one of serious health problems of the rapidly aging society in China. The aim of this work was to preliminary investigate the changes of bone marrow fatty acid composition in the presence of trabecular bone of PMOP and age-matched healthy controls (HC) using 2D intermolecular double-quantum coherence based magnetic resonance spectroscopy (iDQC-MRS). We found monounsaturated fatty acids (P < 0.001) and polyunsaturated fatty acids(p < 0.01) were significant higher lower in the PMOP group. The lower unsaturated fatty acids levels may play an important role in the pathogenesis of PMOP.
Quantitative MR of the Distal Radius Bone Marrow as a marker of Osteoporosis
Authors: De-Levie Tamar K. , Schiffenbauer Yael S. , Druckmann Ido , Rouach Vanessa , Stern Naftali , Binderman Itzhak , Nevo Uri
Published: August 2023

In-vivo detection of osteoporosis-related changes in the distal radius bone marrow, using MR protocols, could provide safe and accessible means for screening and monitoring. A clinical trial was performed, including 26 women assigned into three study groups: healthy premenopausal (n=7), healthy postmenopausal (n=10) and osteoporotic postmenopausal (n=9). Fat composition was evaluated using T2 maps, two-compartment model of T1 and Dixon sequence. The osteoporotic group exhibited higher fat content and lower T2 values compared to the healthy premenopausal group. This study provides proof of concept for the use of the distal radius bone marrow as probing site for osteoporosis.
GRASP-Pro+: GRASP reconstruction with locally low-rank subspace constraint for DCE-MRI
Authors: Solomon Eddy , Bae Jonghyun , Zan Elcin , Moy Linda , Ge Yulin , Feng Li , Kim Gene
Published: August 2023

While the globally low-rank (GLR) model has been demonstrated to be effective in representing global contrast change, it is expected to be less effective for spatially localized signal dynamics. In this work, we propose an improved reconstruction framework, which extends GRASP-Pro using a locally low-rank (LLR) model to represent spatially localized dynamics based on clusters or patches information. This approach has been tested in multiple DCE applications including both cancer and healthy subjects. In addition, we propose an anatomical cluster-based reconstruction approach for brain DCE-MRI.
Rapid CS-Wave MPRAGE acquisition with automated parameter selection
Authors: Varela-Mattatall Gabriel , Kim Tae , Cho Jaejin , Lo Wei-Ching , Gagoski Borjan , Menon Ravi , Bilgic Berkin
Published: August 2023

Wave encoding mitigates g-factor noise amplification in highly accelerated parallel imaging but achieving ultra-high acceleration factors is precluded by the intrinsic “√R” SNR penalty. To overcome this limitation, we propose a compressed sensing-based reconstruction with automatic selection of the regularization weighting. Moreover, we show that CS-Wave is flexible enough to perform well with uniform undersampling. We compare reconstruction performance of CS-Wave against the state-of-art Wave-LORAKS which requires parameter tuning, and evaluate different undersampling patterns at R=12-fold acceleration. Results indicate higher reconstruction quality and showcase the feasibility of ultra-fast Wave-MPRAGE acquisitions.
EigenGRASP: Subject-Specific Temporal-Learning Radial Sampling Image Reconstruction in Dynamic Contrast-Enhanced MRI
Authors: Jafari Ramin , Zarepisheh Masoud , Do Richard , Otazo Ricardo
Published: August 2023

GRASP is an image reconstruction algorithm for free-breathing dynamic contrast-enhanced MRI which uses universal L1-type regularization to suppress undersampling artifacts. We propose to replace it with a subject-specific data-driven L2-type regularization which can improve image quality and decrease reconstruction time.
MORE-SPARKLING: Non-Cartesian trajectories with Minimized Off-Resonance Effects
Authors: R Chaithya G , Daval-Frérot Guillaume , Massire Aurélien , Mailhe Boris , Nadar Mariappan , Vignaud Alexandre , Ciuciu Philippe
Published: August 2023

We augment the recently introduced SPARKLING algorithm and propose an improved mathematical formulation that takes the temporal dependence of the MR signal into account. This prevents the trajectories from sampling similar portions of k-space at different times, thereby reducing distortions and blurring induced by \(B_0\) inhomogenieties. Overall, these trajectories present a smooth distribution over time in k-space and Minimized Off-Resonance Effects (MORE-SPARKLING), verified both retrospectively and prospectively with scans performed in vivo at 3T on a healthy volunteer.
SNR Enhancement of MR Images with Variable Compress Sensed Excitation: vNEX
Authors: Agarwal Harsh , Ahmed Shaik , Sundaresan Rajagopalan , Chatterjee Sudhanya , Rajamani Sajith , Reddy Ashok , Mehta Bhairav , Shanbhag Dattesh , Venkatesan Ramesh
Published: August 2023

MR imaging is signal starve leading to long acquisition time. Multiple averaging/excitation is most common way to boost the SNR. However, it is associated with proportionately long scan time. This abstract presents Variable Compress Sensed Excitation (vNEX) image acquisition and image reconstruction technique which subsample each signal average by compressed sensing fast MRI technique and robust image reconstruction is done to reconstruct MRI images for individual signal averages. The proposed technique is demonstrated for T2w brain MRI where SNR equivalence of 336sec scan time is shown in a 200sec vNEX MRI. Three sampling patterns were proposed and statistically compared.
Imaging Off-Center: How far can we move outside the central imaging region
Authors: Littin Sebastian , Hucker Patrick , Russe Maximilian , Jia Feng , Amrein Philipp , Zaitsev Maxim
Published: August 2023

Imaging outside the predefined and optimized FoV may enhance accessibility for interventional MRI procedures. Here we present different measures to assess the encoding capability of gradient systems in off-center regions. Different clinically establishes sequences are compared at 0.55T and 1.5T regarding their imaging capabilities beyond the predefined target regions.
Phase Stabilization with Motion Compensated Gradient Waveforms for Brain Diffusion Weighted Imaging (DWI)
Authors: Hannum Ariel , Cork Tyler , Fair Merlin , Setsompop Kawin , Ennis Daniel
Published: August 2023

Conventional brain DWI acquisitions are sensitive to physiological motion, which causes shot-to-shot phase variations between images. This makes accelerated, multi-shot imaging harder to achieve. We propose that motion compensated gradient waveforms will improve shot-to-shot phase stability. We found that both velocity and acceleration gradient moment nulling, particularly when diffusion encoding along the z-axis, improves shot-to-shot phase consistency at different cardiac trigger-delay times and reduces phase variation between repetitions for a fixed trigger-delay. We conclude that motion-compensated diffusion encoding gradients improve the phase stability between image shots.
Pulse-width modulation for simultaneous concomitant field compensation and diffusion weighting in double diffusion encoding
Authors: Rauch Julian , Laun Frederik , Ludwig Dominik , Zaitsev Maxim , Ladd Mark , Bachert Peter , Kuder Tristan
Published: August 2023

Intravoxel dephasing caused by Maxwell or concomitant fields can lead to image artifacts as signal voids or falsify the quantitation. In this study, a framework for compensation of concomitant field effects for double diffusion encoding sequences with single pairs of bipolar gradients on each axis is presented. Using pulse-width modulated oscillating gradients with an optimized timing of the oscillating lobes allows for simultaneous diffusion weighting and compensation of the self-squared terms of the concomitant fields as well as for the cross terms. Simulations with realistic parameters reveal the possibility of a signal gain with the proposed method without significant drawbacks.
MR determination of the diffusion propagator: measurements on mouse spinal cord using a benchtop scanner
Authors: Ordinola Alfredo , Jackson Walker , Özarslan Evren
Published: August 2023

We demonstrate the experimental determination of the diffusion propagator, indicating a conditional probability density function with two spatial arguments. To this end, a recently introduced method was implemented on a benchtop MR scanner and incorporated into imaging sequences. The data involving two independent wavenumbers were transformed from the measurement domain to the spatial domain, yielding an apparent diffusion propagator. Experiments on freely diffusing water provides accurate determination of the diffusion propagator while apparent propagators measured in mouse spinal cord reveal significant differences between white and gray matter regions.
Filter-exchange spectroscopy and imaging sensitively detect necrotic cell death in vitro and in vivo
Authors: Kaika Athanasia , Topping Geoffrey , Ballke Simone , Metzler Thomas , Heid Irina , Schillmaier Mathias , Braren Rickmer , Schilling Franz
Published: August 2023

Filter-exchange spectroscopy (FEXSY) and imaging (FEXI) are sensitive to transmembrane water exchange, which is commonly altered during cell death1. Yeast cells in different permeabilization stages were studied with FEXI, DWI and CFDA-AM/ propidium iodide (PI) staining using flow cytometry. Cell populations with 3.8% PI positive staining had 44% increased AXR, but unchanged ADC. At 33% nonvital cells, detection of AXR became unreliable and ADC increased. In vivo FEXI and DWI in EL4 lymphoma, with H&E-confirmed necrotic tumor cells and edema, showed AXR and ADC variations across the tumor, possibly due to differing vitality cell stages.
A Magnetic Resonance Spectroscopy Method in Characterization of Blood Metabolomics for Alzheimer’s Disease
Authors: Cheng Leo , Muti Isabella , Weng JianXiang , Zhong Anya , Kivisäkk Pia , Hyman Bradley , Arnold Steven
Published: August 2023

Currently, a definitive AD diagnosis can only be achieved at autopsy, through pathology examinations of brain tissue. No non- or less-invasive examination can yet diagnose and characterize AD during the patient’s life, in turn limiting insights into potential strategies for countering AD modes of progression. Here, using HRMAS MRS, we studied human blood plasma samples obtained from AD and non-AD subjects to reveal potential AD-associated metabolomic changes measurable in blood, which may assist with AD diagnosis and, more importantly, contribute to the development of precision treatments.
The relationship between hippocampal NAA and functional connectivity within the Default Mode Network in Mild Cognitive Impairment
Authors: DeMayo Marilena , Lv Jinglei , Duffy Shantel , Naismith Sharon , Calamante Fernando
Published: August 2023

We investigated the association between two MR markers of Mild Cognitive Impairment (MCI): N-Acetylaspartate (NAA) measured by MR Spectroscopy within the hippocampus; and functional connectivity within the Default Mode Network (DMN). We showed differential relationships between functional coupling/connectivity and NAA in MCI and controls, with an association between these measures in MCI not evident in controls. For those with MCI, we detected 20 connections within the DMN associated with NAA levels, with stronger connectivity associated with lower NAA levels. This suggests change in NAA within the hippocampus is associated with functional change within the DMN for those with MCI.
Numerical optimization of 5D cardiac and respiratory motion-resolved CMR imaging for the assessment of left ventricular function
Authors: Yerly Jérôme , Roy Christopher , Milani Bastien , Piccini Davide , Bustin Aurélien , Falcão Mariana , van Heeswijk Ruud , Stuber Matthias
Published: August 2023

The free-running framework (FRF) was recently proposed to address the limitations of current techniques to assess left ventricular (LV) ejection fraction (LVEF). However, the accuracy of FRF to assess LVEF has yet to be quantitatively examined. This work rigorously quantifies and optimizes the effect of the regularization weights on LVEF and several image quality metrics using a numerical phantom with well-controlled boundary conditions, and validates the results in in-vivo 5D FRF data. The results demonstrated that the combination of regularization weights that are optimal in terms of image quality do not correspond to the optimal weights for LVEF assessment.
An SSFP-SPGR Multi-sequence Cardiac Cine-Tag Acquisition Approach in One Breath-hold
Authors: Goes Jacob , Nguyen Vivian , Gorre Donovan , Hibino Narutoshi , Wang Hui , Vaicik Marcella , Patel Amit , Kawaji Keigo
Published: August 2023

Multi-Contrast single breath-hold acquisition for cardiac MRI is highly desirable but is rate-limited by the need for a dedicated pre-scan per each acquisition. We revisit the notion of the necessary conditions for repeated preparation calibration steps, with the intent of loosening or selectively bypassing them in consecutive scan acquisitions. Under matched geometric conditions that account for sensitivities especially to off-resonance, we propose a simple bSSFP-SPGR based dual-acquisition method with a single intensive Cine calibration followed by a truncated SPGR calibration. This approach is demonstrated as Cine-Tag SSFP-SPGR CMR method that allows for one breath-hold functional acquisition of both scan sequences.
Texture Analysis Identifies Significant Pattern Differences in Pediatric Heart Transplant Recipients with and without Acute Rejection
Authors: Samyn Margaret , Yan Ke , George-Durrett Kristen , Godown Justin , Crum Kimberly , Christ Maryanne , Chan Kak-Chen , Chan Kak-Chen , Bearl David , Dodd Debra , Hernandez Lazaro , Soslow Jonathan , Damon Bruce
Published: August 2023

Acute rejection (AR) continues to cause significant morbidity and mortality in pediatric heart transplant recipients (PHTx). Endomyocardial biopsy is the standard-of-care for diagnosis of AR, but it is invasive and associated with morbidity and mortality and can miss patchy AR. Cardiac magnetic resonance (CMR) was performed using parametric mapping and novel texture analysis to detect patterns of myocardial edema and fibrosis. Patients with AR had significant differences in texture analysis compared with patients without AR. CMR with texture analysis has potential as a non-invasive method for detection of AR in PHTx.
Evaluation of diastolic (dys-)function using CMR feature tracking in all four cardiac chambers
Authors: Fehrmann Ana , Maintz David , Baeßler Bettina
Published: August 2023

Due to demographic changes, the prevalence of cardiac conditions predisposing to diastolic dysfunction (DD) is rising steadily. The main focus of non-invasive assessment of parameters for DD has been on left ventricular strain alterations. In this prospective study, we performed strain analysis of all 4 cardiac chambers using cardiac magnetic resonance feature tracking in patients with echocardiographically diagnosed DD and compared the results to a healthy control group. Left atrial strain parameters proved to be the most potent predictors of DD and allowed for a clear separation between patients and age-matched controls.
The relationship between cardiac fiber structure and regional function after myocardial infarction in rats
Authors: Bendiksen Bård , Nordén Einar , Sjaastad Ivar , Zhang Lili , Espe Emil
Published: August 2023

Little is known about the relationship between cardiac function and myocardial fiber structure after myocardial infarction (MI). We hypothesized that post-MI remodeling of left ventricular fiber structure would be reflected in changes in the regional strains. Strains and cardiac fiber structure were measured using MRI in five rats with MI, and three sham-operated rats. Transmural variation in fiber helix angles was reduced adjacent to the infarct. This reduction was associated with reduced radial, longitudinal, and endocardial circumferential strain, and improved epicardial circumferential strain in the adjacent zone. Our findings emphasize the relevance of cardiac fiber structure remodeling after myocardial infarction.
Impact of Acute Intermittent Hypoxia on BOLD fMRI measures of cerebrovascular reactivity
Authors: Hoggarth Mark , Stickland Rachael , Hemmerling Kimberly , Sandhu Milap , Bright Molly
Published: August 2023

We assess the effects of an emerging intervention for rehabilitation, termed acute intermittent hypoxia (AIH), on cerebrovascular reactivity (CVR) as measured with BOLD fMRI. Lag-optimized CVR was measured pre- and post-AIH using a breath-hold task paradigm in 8 healthy participants. Five participants achieved the target drop in oxygen saturation (SpO2) to 85%; 3 did not. Overall changes in group mean CVR were varied following AIH, slightly increasing for those who achieved the targeted SpO2, and decreasing in those who did not. This work motivates continued study of the effects of AIH interventions on CVR.
Variability of ADC Estimates Between-Scanners from Whole Body Imaging is Dominated by Within-Scanner Variance
Authors: Lamb Alistair , Bainbridge Alan , Parry Tom , Rogers Harriet , Taylor Stuart , Zhang Hui , Barnes Anna
Published: August 2023

We investigate the reliability of Whole-Body Imaging ADC estimates from subjects tested and retested within- and between-scanners from different vendors with minimal differences in acquisition protocol and post-acquisition analysis. We show substantial within-subject variation in extracranial ADC estimates within- and between-scanners as measured by Limits of Agreement. We additionally show between-scan variability between scanners is dominated by between-scan variability within a scanner. Furthermore, averaging across subsequent within-scanner examinations does not substantially improve reliability of ADC estimates. We therefore conclude a post-acquisition method for reducing within-scanner variation is required to improve the reliability of ADC estimates.
23Na in vivo MRI with 1mm isotropic resolution and real-time prospective motion correction implemented in Pulseq
Authors: Zaitsev Maxim , Zaric Olgica , Trattnig Sigfried
Published: August 2023

Sodium imaging has a great potential for basic research and clinical MRI, but its applications are limited due to poor SNR achievable in typical in vivo scanning times. Image acquisition times can be substantially extended if involuntarily subject motion is compensated for, e.g. by using an external optical motion tracking system. In this proof-of-concept study we demonstrate 1mm isotropic 23Na MRI with the achieved image quality sufficient for the anatomical orientation based on the native sodium images. The used ultra-short echo time 3D imaging sequence was implemented in Pulseq, an open-source platform-independent development environment.
Comparison of CT versus Zero Echo Time MRI techniques in the management of patients with shoulder instability
Authors: Carretero Laura , García-Polo Pablo , Congo Alejandro , Carl Michael , McKinnon Graeme C , Fung Maggie , Padrón Mario
Published: August 2023

In this study we evaluate the viability of using ZTE, a novel MRI sequence for bone imaging, with deep-learning (DL) reconstruction to assess glenohumeral shoulder instability, aiming to improve signal-to-noise ratio (SNR) and get comparable images to CT, the gold standard technique for surgical planning. Bone loss measurements were performed on both techniques achieving almost perfect inter-modality agreement on 20 patients. This approach could prevent the patient from receiving ionizing radiation concomitant to CT examination and could be combined in a single routine shoulder examination with other MR sequences for a complete study and optimized patient workflow.
Proton magnetic resonance spectroscopy of the distal metacarpus/tarsus in Thoroughbred racehorses with and without catastrophic fractures.
Authors: Hewitt-Dedman Charlotte , Taylor Sarah , Schwarz Tobias , Daniel Carola , Pressanto Maria Chiara , Kershaw Lucy
Published: August 2023

Fractures of the third metacarpal/tarsal bone are common in racehorses. Racehorse cadaver limbs underwent single voxel magnetic resonance spectroscopy (MRS) and computed tomography. The percentage fat content (FC) and the mean bone mineral density (BMD) was calculated at 3 locations within the bone. A significant negative correlation was identified for mean BMD and percentage FC for all condyles and in bone marrow of the third metacarpal/tarsal distal diaphysis. The median percentage FC was lower in horses with fractures compared to controls. These findings suggest that fat and bone are capable of mutual regulation in Thoroughbred racehorses.
Protocol Optimization of Spectro-Dynamic MRI
Authors: van Riel Max , Huttinga Niek , Bruijnen Tom , Sbrizzi Alessandro
Published: August 2023

Inferring dynamical information from (bio)mechanical systems at a high temporal resolution can be very valuable for cardiovascular or musculoskeletal applications. Spectro-dynamic MRI is a recently proposed method that combines a measurement model and a dynamical model to characterize dynamical systems directly from k-space data. Both the displacement fields and the underlying dynamical parameters are estimated. In this work, different sampling trajectories and acquisition orderings are used to investigate the trade-off between temporal resolution and k-space coverage. A phantom experiment shows that it is possible to reconstruct a moving image from the estimated dynamics at a temporal resolution of 4.4 ms.
Rapid prototyping of a motion-robust 2D Radial GRE sequence with reduced acoustic noise generation using Pulseq
Authors: Marchetto Elisa , Zaitsev Maxim , Gallichan Daniel
Published: August 2023

A radial GRE-sequence was modified using Pulseq to reduce the acoustic noise amount produced by the rapid switching of gradient currents without excessively increasing the TR-time. Prospective motion-correction was performed using a markerless tracking device that sent the motion estimates to the scanner via the libXPACE framework, incorporated directly into Pulseq, to update gradients and RF pulses during the MR scan. The quieter sequence resulted in a acoustic noise reduction of 6 dB(A) (i.e. a factor of 2) compared to the standard one. Image quality was greatly improved using prospective motion-correction in the case of deliberate motion during the scan.
More Efficient SPGR 3D Abdominal Imaging Using an Interleaved Randomized Spoiler
Authors: zhong zheng , Sandino Christopher , Syed Ali , Pauly John , Vasanawala Shreyas
Published: August 2023

3D SPGR is commonly used clinically for contrast-enhanced body imaging, but requires time for a gradient spoiler every TR. This consumes up to 40% of scan time, even for a non-cartesian trajectories with relatively long readouts, such as cones. Removing the spoiler can save time but causes severe artifacts. In this study, we propose a novel approach of applying interleaved, randomized spoilers to a motion-robust 3D-cones sequence. The feasibility of the approach to shorten acquisition time without introducing image artifacts was validated on both healthy subjects and patients.
Tennisball: slew-efficient trajectory design for 3D-radial imaging
Authors: Nataraj Gopal , Lustig Michael
Published: August 2023

What is the most efficient path to traverse a sphere? For a spherical gap-minimizing efficiency definition and a particular path length, the answer happens to resemble the seam lines of a tennis ball. Here we explore properties of this general class of spherical trajectories and investigate their application to slew-constrained ZTE imaging. Static and motion-resolved imaging results demonstrate that Tennisball trajectories can achieve competitive performance with existing methods but with ~30-40% lower peak slew.
Bipolar Partial Echo Imaging
Authors: Eggers Holger , Keupp Jochen
Published: August 2023

Partial echo imaging is widely used in angiography to shorten the echo time and reduce flow-induced signal loss. However, sampling only an asymmetric part of k-space basically ignores high-frequency phase and thus causes signal alteration as well. In the present work, bipolar partial echo imaging is introduced to cover the full k-space sparsely with a Cartesian partial echo measurement. It involves reversing the polarity of the readout gradient during the acquisition and recovering missing data in the reconstruction without assuming smoothness of the phase. The potential of bipolar partial echo imaging is demonstrated in phantom and first volunteer experiments.
Repeatability of Diffusion Kurtosis Tensor Parameters in Muscles of the Lower Legs
Authors: Mathew Ethan , Quarles Chad , Ragunathan Sudarshan , Dortch Richard
Published: August 2023

This study examines the repeatability of quantitative measures obtained from the lower legs using a diffusion kurtosis tensor imaging sequence with a scan time of just 13 minutes. Test-retest data was acquired, and kurtosis parameters were calculated for both sets of data. Muscle groups were segmented, and repeatability was assessed by muscle group. In both the medial gastrocnemius and tibialis anterior, kurtosis fractional anisotropy and fractional anisotropy showed highest repeatability, as well as mean diffusivity in the medial gastrocnemius.
How does language fMRI activation in tumour patients compare to healthy volunteers?
Authors: Franklin Rachael , de Vita Enrico , Brumer Irène , Jarosz Jozef , Borri Marco
Published: August 2023

Task-based language fMRI datasets from healthy volunteers (15) and tumour patients (4 with lesions near Wernicke’s area, 6 with lesions near Broca’s area) were compared, to assess the similarity of activation location and extent. Expected areas of the language network were consistently localised in both patients and volunteers. Although patients showed more variation in the extent and strength of activation, our activation metrics for the full patient cohort show similar amount of overlap compared to a size-matched group of volunteers. Furthermore, patient with lesions near Broca’s area had highly consistent activation in specific locations.
Correlation between fMRI signals and oscillatory neuronal responses during audiovisual information processing
Authors: Lee Hsin-Ju , Nummenmaa Lauri , Yu Hsiang-Yu , Lee Cheng-Chia , Chou Chien-Chen , Chen Chien , Kuo Wen-Jui , Lin Fa-Hsuan
Published: August 2023

We studied how fMRI signal is related to neural oscillations by taking both fMRI and invasive recordings from epilepsy patients. Specifically, we examined the neurovascular coupling during complex naturalistic stimuli processing. A significant negative correlation between gamma-band neural oscillations at hippocampus/amygdala and fMRI signals was found at the amygdala, hippocampus, and inferior occipital lobes while viewing short movie clips. These correlations sustain across gamma, beta, and alpha bands. The left angular gyrus shows a positive correlation between neural oscillations and fMRI dynamics at the theta band.
Deep artifact suppression for interventional cardiac MR-thermometry
Authors: Jaubert Olivier , Ozenne Valery , Yon Maxime , Montalt-Tordera Javier , Steeden Jennifer , Muthurangu Vivek , Quesson Bruno
Published: August 2023

A novel thermometry acquisition and a fast deep learning based image reconstruction were combined for cardiac interventional thermometry at high spatial (0.86×0.86mm2) and temporal (0.97s) resolutions, robust to motion and susceptibility artefact and independent of external ECG-gating. The method was tested in phantom and in-vivo in a sheep. The proposed deep learning method outperformed the state-of-the-art algorithm in terms of SNR and paves the way for clinical studies.
Deep subspace transfer learning for SMS image reconstruction from single-slice training: Application to CMR Multitasking
Authors: Chen Zihao , Lee Hsu-Lei , Mao Xianglun , Cao Tianle , Xie Yibin , Li Debiao , Christodoulou Anthony
Published: August 2023

CMR multitasking is promising for quantitative cardiac imaging, and can achieve fast three-slice quantification when combined with simultaneous multi-slice (SMS) acquisition. However, slow non-Cartesian iterative reconstruction is a barrier to clinical adoption. Deep learning can accelerate reconstruction, but the SMS training data are currently limited. Here we propose a data-consistent deep subspace transfer learning strategy that trains on single-slice T1 CMR multitasking data but is applied to SMS-encoded T1 CMR multitasking image reconstruction. The proposed strategy is >40x faster than the conventional SMS reconstruction, resulting in an equally better image quality and comparably precise T1 as in single-slice reconstruction.
GABA and Glutamate/Glutamine concentrations in the dACC of amphetamine treated adult ADHD patients
Authors: Geiger Yasmin , Gonen-Shahar Marganit , Vainstein Gabriel , Ruban Angela , Tal Assaf
Published: August 2023

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by irregular levels of hyperactivity, impulsivity and inattention. It is commonly linked to dopamine and norepinephrine balance. Several studies suggested connections to γ-amino butyric acid (GABA) and glutamate (Glu) imbalance in the dorsal anterior cingulate cortex (dACC). Here we use 1H-MRS to study GABA and glutamate + glutamine (Glx) levels in the dACC of ADHD patients, before and after pharmacological treatment and compared to healthy adults. We found no metabolic difference between ADHD and control group and no change after amphetamine treatment. We found no metabolic correlation to ADHD scores.
Disruptions of functional and structural networks in classic trigeminal neuralgia patients
Authors: Zhang Pengfei , Wang Jun , Hu Wanjun , Ma Laiyang , Liu Guangyao , Ai Kai , Zhang Jing
Published: August 2023

Classic trigeminal neuralgia (CTN) has been proven related to functional or morphological alterations in critical brain regions. To test the simultaneous changes of the topological properties of structural networks (SN), functional networks (FN), as well as their couplings, we constructed SN using diffusion tensor imaging (DTI) data and FN using resting-state functional magnetic imaging (rs-fMRI) data from 29 CTN patients and 34 healthy controls (HCs). The patients showed the wide disruptions of global and local topological organizations in SN and FN, together with the abnormal coupling relationships. Our findings may provide novel perspectives for understanding the pathophysiological mechanisms of CTN.
Longitudinal resting-state functional connectivity changes with medication and nutrition treatment in chronic mild traumatic brain injury
Authors: vedaei Faezeh , Alizadeh Mahdi , Zabrecky George , Wintering Nancy , Bazzan Anthony J. , Monti Daniel A. , Newberg Andrew B. , Mohamed Feroze B.
Published: August 2023

This study provides comprehensive evaluation of functional rs-fMRI biomarkers that are associated with chronic mTBI symptoms and predicting treatment outcome and patient recovery. We evaluate the effect of medication and nutrition treatments on brain function and cognitive performance in chronic mTBI patients using resting-state fMRI metrics and neuropsychological test. We propose that treatment strategies compensate mTBI disrupt communication between brain network nodes. Our results help understanding the implication of treatment strategies in chronic mTBI patients and prediction of outcomes in brain function and cognitive recovery.
A comparison of tractography and fMRI pre-surgical planning approaches with intraoperative mapping-based validation
Authors: Radwan Ahmed , Emsell Louise , Cleeren Evy , Kovacs Silvia , Van Hoylandt Anais , Peeters Ronald , De Vleeschouwer Steven , Theys Tom , Dupont Patrick , Sunaert Stefan
Published: August 2023

Accurate presurgical brain mapping enables preoperative risk assessment and intraoperative guidance to minimize postoperative deficits. Here we compare mapping accuracy of task-based fMRI (tbfMRI), BOLD and Functionnectome resting state fMRI (rsfMRI), DTI and constrained spherical deconvolution (CSD)-based tractography in 21 preoperative neurosurgical patients using intraoperative electrical stimulation (DES) as the ground truth for functional mapping. Accuracy was estimated based on minimum distance between MRI-based mapping and positive DES coordinates. We report that CSD outperforms DTI, and rsfMRI performs similarly to tbfMRI using DES. This demonstrates the potential benefits of using CSD and rsfMRI in clinical practice.
Insights to the diffusion MRI ‘crossing fiber problem’: Characterizing the micro-structure in an MRI voxel using synchrotron radiation imaging
Authors: Kjer Hans , Andersson Mariam , Pacureanu Alexandra , Dahl Vedrana , Dahl Anders , Dyrby Tim
Published: August 2023

Complex fiber regions where multiple tracts and bundles intersect are challenging to study with diffusion weighted MRI (DWI), due to the anatomical variation and 3D complexity within the volume covered by the measure voxel. Using x-ray nano-holotomography (XNH) we have been able to obtain and analyze a volume from a complex fiber region and make a comparison against DWI measurements from the same location of the same ex-vivo monkey brain. We derive comparable micro-structural features in the form of orientation distributions and anisotropy measures and show strong connections between them.
Benchmarking learned non-Cartesian k-space trajectories and reconstruction networks
Authors: R Chaithya G , Ciuciu Philippe
Published: August 2023

We benchmark the current existing methods to jointly learn non-Cartesian k-space trajectory and reconstruction: PILOT1, BJORK2 and compare them with those obtained from recently developed generalized hybrid learning (HybLearn) framework3. We present the advantages of using projected gradient descent to enforce MR scanner hardware constraints as compared to using added penalties in the cost function. Further, we use the novel HybLearn scheme to jointly learn and compare our results through retrospective study on fastMRI validation dataset.
Evaluation of Multicoil SENSE Reconstruction of Undersampled Data using a Human Observer Model of Signal Detection
Authors: O'Neill Alexandra , Kemp Tavianne , Lingala Sajan , Pineda Angel
Published: August 2023

We evaluated undersampling in MRI using a multicoil SENSE reconstruction with no regularization based the detection of signals by humans. We used a sparse difference-of-Gaussians (S-DOG) model to predict human performance in the detection of a small and large signal in anatomical backgrounds. The prediction was then validated using human observer two-alternative forced choice (2-AFC) tasks. Our model predicted a decrease in performance for both the small and large signal from 4X to 5X acceleration. Our observer study validated that prediction. This approach may lead to a way of assessing image quality that predicts human performance with fewer observer studies.
Optimal Phase-Encoding Schemes for Regional Bias and Reproducibility of Diffusion MRI derived Measures
Authors: Irfanoglu M. Okan , Clark Grayson , Pierpaoli Carlo
Published: August 2023

Our goal is to determine whether diffusion MRI acquisitions with different phase-encoding directions (PEDs) result in comparable quantitative measures in different regions of the human brain, or whether PEDs introduce a bias. Additionally, we aim to determine if for a given region, a set of PEDs has better reproducibility. For several regions, PA phase-encoding direction resulted in values that were significantly different than the other three. LR/RL phase-encoding was more reproducible compared to AP/PA in most brain regions, with frontal white matter being the exception. The main source of these reproducibility variations was identified as ghosts overlapping with brain regions.