bluuebunny/crossref_metadata_2025 huggingface dataset:
Ex-vivo microbleed detection in community-based older adults using confidence aware learning
Authors: Nikseresht Grant , Evia Arnold , Bennett David , Schneider Julie , Agam Gady , Arfanakis Konstantinos
Published: August 2024

Detection of cerebral microbleeds (CMBs) on ex-vivo gradient echo MR images is an important task in MRI-pathology studies in older adults. The goal of this study was to develop a confidence-aware ex-vivo CMB detection algorithm that outputs interpretable probabilities and ranking of CMB candidates on brain MRI scans of community-based older adults. The present study demonstrates that training an ex-vivo CMB detection model with confidence-aware deep learning, a technique for improving confidence estimation and ordinal ranking of examples in classification models, improves detection performance and prediction interpretability.
Constructing age-specific MRI brain templates based on a uniform healthy population across life span with transformer
Authors: Zhang Chenghao , Morgan Mikhail , Yang Yanting , Tian Ye , Guo Jia
Published: August 2024

Image registration is currently employed to assist with diagnostic tasks such as neurodegenerative disease diagnosis. Aging also affects the brain, and our knowledge of age-related brain diseases is currently encumbered by age-induced bias; understanding the mechanisms of neurodegenerative diseases requires a deeper understanding of aging. Thus we have devised a pipeline for generating age-specific templates using a novel deep-learning algorithm detailed in a separate report. Our results show qualitative changes in brain morphology across age groups, and tissue segmentation was performed on each template to calculate volumetric changes in brain matter across time.
Robust Electromagnetic Interference (EMI) Elimination for RF Shielding-Free MRI via Active EMI Sensing and Deep Learning MRI Signal Prediction
Authors: Zhao Yujiao , Hu Jiahao , Lau Vick , Xiao Linfang , Leong Alex T. L. , Wu Ed X.
Published: August 2024

MRI scans are commonly performed inside a fully-enclosed RF shielding room, posing stringent installation requirement and unnecessary patient discomfort. This study develops a strategy of active EMI sensing and deep learning MR signal prediction using residual U-Net for RF shielding-free MRI. We implemented it on an ultra-low-field 0.055T head MRI scanner. Our experimental results demonstrated that this strategy could directly and accurately predict EMI-free MRI signals from the signals acquired by MRI receive coil and EMI sensing coils. It worked robustly with strong and dynamically varying EMI sources, yielding significantly improved brain image quality.
A first application of the ILAE consensus protocol for 7T epilepsy imaging in addition to clinical practice
Authors: Hangel Gilbert , Kasprian Gregor , Chambers Stefanie , Haider Lukas , Lazen Philipp , Koren Johannes , Diehm Robert , Moser Katharina , Tomschik Matthias , Wais Jonathan , Winter Fabian , Zeiser Vitalij , Gruber Stephan , Aull-Watschinger Susanne , Traub-Weidinger Tatjana , Baumgartner Christoph , Feucht Martha , Dorfer Christian , Bogner Wolfgang , Trattnig Siegfried , Pataraia Ekaterina , Rössler Karl
Published: August 2024

In a cohort of 38 patients with pharmacoresistant focal epilepsy, our implementation of the 2021 ILAE 7T consensus protocol found lesions in 19% of 3T MR-negative cases and improved delineation of lesions in 88% of 3T MR-positive cases, with statistically significant higher detection confidence at 7T. Our results conform to literature and show the surplus effect of the consensus protocol in addition to clinical standard diagnostics and point at a potential main use of better surgical planning in known lesions.
Combined 18F-FDG PET/DTI reveals concurrent more extensive brain damage in mesial temporal lobe epilepsy
Authors: Huang Chuan , Zhao Tianyun , Yuan Siyu , Huang Hui , Zhang Miao , Luo Jie
Published: August 2024

Mesial temporal lobe epilepsy is the most common type of drug-resistant epilepsy, with hippocampus sclerosis (HS) being its most common pathology. Anterior temporal lobectomy is the most common surgical strategy for these patients, many still suffer from seizures post-surgery, which may relate to their extensive brain network damage. 18F-FDG-PET is sensitive to metabolic changes in the epileptogenic zone. DTI can assess the integrity of white-matter tracts. In this study, we investigated the changes in glucose uptake, white-matter tracts, and their differences in brain networks of MR-HS versus MR-negative patients using simultaneous PET/MR, and studied if these changes coincide topographically.
High Temporal Resolution Head Motion Tracking using Pilot Tone and 3D Radials
Authors: Wallace Tess , Ariyurek Cemre , Calakli Fatih , Kober Tobias , Warfield Simon , Afacan Onur
Published: August 2024

Radial acquisitions are inherently motion-robust and facilitate self-navigation, however the frequency of motion updates from navigator images is limited. Pilot tone (PT) enables continuous motion sensing, but estimation of quantitative motion parameters requires a subject-specific calibration. In this work, we propose (i) using PT motion detection to guide navigator-based motion estimation from a 3D radial acquisition and (ii) using these measurements to calibrate a PT motion model in order to provide high temporal resolution quantitative motion tracking. This hybrid approach demonstrates improved retrospective correction results with reduced blurring and facilitates PT motion tracking for subsequent scans.
Motion-Compensated Slice-by-Slice ∆B0 Shimming with an AC/DC Shim Coil and Dual-Echo vNavs
Authors: Arango Nicolas , Frost Robert , Wighton Paul , Stockmann Jason , Andronesi Ovidiu , van der Kouwe Andre
Published: August 2024

Subject motion results in intra-scan ∆B0 changes which are uncompensated in conventional ∆B0 shimming methods. Rapidly switchable shim currents and ∆B0 vNavigators together enable motion-compensated shimming. We have demonstrated successful measurement, calculation, and application of motion-compensated slice-by-slice shims using and AC/DC coil and vNav ∆B0 maps. Motion-compensated slice-by-slice homogeneity shimming improves shim robustness to subject motion and enables compatibility with changing slice prescriptions of prospective motion correction.
Self-navigation using fat navigators for motion immune diffusion weighted-imaging via chemical-shift encoded multi-shot EPI
Authors: Dong Yiming , Koolstra Kirsten , Riedel Malte , van Osch Matthias J.P. , Börnert Peter
Published: August 2024

The presence of fat is a challenge in diffusion-weighted EPI. Recently, chemical-shift encoded approaches found interest, as a smart way of signal averaging, doing water/fat separation and diffusion phase navigation in the reconstruction. However, the dominant signal character of fat in diffusion could actually also be exploited as an advantage by forming a shot-specific fat navigator to track and correct for macroscopic in-plane motion, combined with a model-based self-navigated water/fat decomposition. This allows to correct for both physiological and macroscopic in-plane motion effects in DWI when estimating water and fat resolved images from chemical-shift encoded multi-shot EPI data.
A Brain-Behavior Interaction Analysis for Dyadic Brain Responses during Eye Contact between Parents and Children
Authors: Lee Ray , Friedman Joshua , O'Brien Maria , Ren Zhihua , Hong Linbi , Sajda Paul , Tottenham Nim
Published: August 2024

By combining hyperscan fMRI (hfMRI) and the facial action coding system (FACS), we introduce a new brain-behavior interaction analysis that can identify the underlying brain networks for perception and expression for different emotions during eye contact. It consists of three steps. 1) The affective facial muscle movements are encoded by facial action units (FAU) using FACS. 2) The specific emotional FAUs subserve the regressors for the univariant analysis on hfMRI data. 3) The brains’ activation maps are transformed into brain networks by multivariant analysis. It provides an approach to quantify affective interaction and emotional states.
Zero echo time MB-SWIFT functional MRI of orientation selective deep brain stimulation of the rat infralimbic cortex using tetrahedral electrode
Authors: Laakso Hanne , Paasonen Ekaterina , Gureviciene Irina , Narvaez Omar , Lehto Lauri , Paasonen Jaakko , Salo Raimo , Gurevicius Kestutis , Mangia Silvia , Michaeli Shalom , Tanila Heikki , Sierra Alejandra , Gröhn Olli
Published: August 2024

In this study, the response of the amygdala to 3D orientation selective deep brain stimulation of the infralimbic cortex (IL) was followed using MB-SWIFT fMRI. The aims were to investigate how the fMRI response of the amygdala changes whilst changing the stimulation angle in the IL, and to detect the effects in resting-state functional connectivity when sustained 130 Hz stimulation of the IL at the most effective stimulation angle is used. The fMRI response of the amygdala showed dependence on the stimulation angle and inter-animal variation, which can be exploited for optimizing the stimulation effects.
Interrogation of resting-state effective connectivity by whole-brain fMRI with optogenetic silencing
Authors: Moon Hyun Seok , Vo Thanh , Kim Seong-Gi
Published: August 2024

Mapping resting-state effective connectivity by cortical optogenetic activation of inhibitory neurons in mice
Region-of-Interest Based Statistical Analysis of the 2019 QSM Challenge
Authors: Fuchs Patrick , Milovic Carlos , Shmueli Karin
Published: August 2024

Since its inception, the most recent QSM challenge and corresponding dataset have helped to improve dipole-inversion algorithms. To date, only global metrics have been used to evaluate performance of these algorithms. Typically, in clinical applications of QSM, the susceptibility value in a specific brain region or structure is of interest. Therefore, we compared the accuracy of QSM algorithms in 28 regions in several ways including regional metrics and median differences, which is important to facilitate clinical translation of QSM. We found that, according to regional metrics, some direct QSM methods are surprisingly accurate considering their low global scores.
In-vivo delineation of fine structures in the human brain using high resolution deep learning-powered chi-separation
Authors: Ji Sooyeon , Park Juhyung , Shin Hyeong-Geol , Kim Minjun , Lee Jongho
Published: August 2024

Fine structures in the human brain are delineated in the positive and negative susceptibility maps reconstructed in less than 25 min of scan time. The reconstruction pipeline consists of four deep learning networks, each of which performs multi-echo denoising, QSM reconstruction, χ-separation, and super-resolution. The reconstructed maps delineate two laminar structures within globus pallidus, the fibers of internal capsule, and nigrosome structures in the substantia nigra.
Tissue orientation effects on T2 relaxation in fresh and fixed spinal cord white matter
Authors: Medina Michelle , Bartels Lara , Doucette Jonathan , Yung Andrew , Bale Kirsten , Kozlowski Piotr , Birkl Christoph , Rauscher Alexander
Published: August 2024

In this study, we investigated the orientation dependence of T2 in fresh and fixed spinal cord white matter (WM). Scans from three pig spinal cord tissues were acquired at 7T at 6 different orientations with respect to the main magnetic field. We found a considerable orientation dependence in the short fraction relaxation rate R2 (=1/T2) in fresh WM as opposed to a weak orientation effect in fixed WM. To our knowledge, this is the first direct comparison of orientation dependence in a WM tissue sample in the fresh and fixed state. Orientation dependence was not observed in long fraction R2.
A modular sparse hemispherical transmit/receive phased array for microbubble-mediated MR-guided focused ultrasound brain therapy
Authors: Jones Ryan , McMahon Dallan , Leavitt Dallas , Ramdoyal Rohan , Lee Kang , Kan Wai , Yang Steven , Chen Yi-Shiuan , Adams Chris , Hynynen Kullervo
Published: August 2024

MRI is commonly employed to assess microbubble-mediated focused ultrasound (FUS) treatment outcomes, but is restricted to post-treatment evaluations due to its low temporal resolution. Here, we describe a modular sparse hemispherical transmit/receive phased array for microbubble-mediated FUS brain therapy and simultaneous 3D passive cavitation imaging (PCI) for real-time intraoperative treatment monitoring and control. The device was evaluated via MR-guided FUS experiments in rabbits. The utility of 3D PCI in calibrating FUS exposure levels and predicting MRI-inferred tissue damage volume distributions resulting from high target level sonications was demonstrated.
DIRECT: non-contrast-enhanced relaxation-based flow-independent intracranial MR angiography using modified REACT
Authors: Yoneyama Masami , Sakai Takayuki , Goto Yasuhiro , Nakamura Masanobu , Murayama Daichi , Nagao Michinobu , Zhang Shuo , Abe Kayoko , Hamatani Yutaka , Kodaira Kazuo , Ogawa Takumi , Kato Mana , Shiina Isao , Van Cauteren Marc
Published: August 2024

A new non-contrast-enhanced, relaxation-based, flow-independent MRA method, called Relaxation-Enhanced Angiography without ContrasT (REACT) has recently been proposed for vascular imaging. One of the major limitations of REACT is that bright signal of long-T1 fluids such as CSF is visible, which can obscure vascular structure in the intracranial vessels. We developed a new sequence, called DIRECT (Dual-Inversion REaCT) with modified magnetization preparation scheme of REACT to suppress CSF signals while maintain the high signal intensity from vessels. DIRECT enables robust and high-quality whole-brain intracranial MR angiography with uniform fat, CSF and brain parenchyma suppression within clinically feasible scan time.
Automatic identification of Moyamoya disease based on time-of-flight MR angiography
Authors: Tan Zheng , Lu Mingming , Liu Shuai , Liu Shitong , Zhang Hongtao , Tang Xiaoying , Cai Jianming , Shang Fei
Published: August 2024

Moyamoya disease (MMD) is a rare chronic progressive cerebrovascular disease that causes strokes. For the diagnosis of MMD, time-of-flight magnetic resonance angiography (TOF-MRA) can be an alternative to digital subtraction angiography (gold standard) owing to its non-invasive and radiation-free attributes. In this study, the deep learning method (ResNet-50) was used for MMD automatic diagnosis on the maximum intensity projection images from 3D TOF-MRA, and five-fold cross-validation was used for validation. The method exhibits the accurate ability (AUC: 0.990 ± 0.008, accuracy: 0.933 ± 0.063) to identify MMD and has the potential to improve the clinical management of MMD.
Biventricular and Hemodynamic Assessment under Multi-stage Exercise using Real-time CMR
Authors: Chandrasekaran Preethi , Chen Chong , Liu Yingmin , Crabtree Christopher , Arshad Syed Murtaza , Tong Matthew , Han Yuchi , Ahmad Rizwan
Published: August 2024

A comprehensive exercise stress cardiovascular MRI (Ex-CMR) was performed in twelve healthy subjects. Biventricular quantification was performed from real-time cine, while hemodynamic parameters in the ascending aorta and main pulmonary artery were estimated using real-time flow. The acquisition process was repeated two to three times at increasing exercise intensities. The highly accelerated (R = 7-8 for cine and R = 16 for flow) real-time data were reconstructed inline using Gadgetron-based compressed sensing reconstruction. In agreement with the literature, the ejection fraction and cardiac output correlated positively with exercise intensity.
Dual Venc 5D flow MRI with Increased Velocity Dynamic Range: An in-vitro and in-vivo Validation and Feasibility Study
Authors: Weiss Elizabeth , Baraboo Justin , Ma Liliana , Falcão Mariana , Roy Christopher , Stuber Matthias , Markl Michael
Published: August 2024

We illustrate a pilot study of the first implementation of dual-venc 5D flow MRI. We found excellent voxel-wise agreement with single-venc 5D flow in a pulsatile phantom. In two healthy controls, we find good agreement, but identify unexpected aliasing in the dual venc 5D flow which requires further investigation.
Acute Effects of Electronic and Tobacco Cigarette Aerosol Inhalation on Vascular Function Detected at Quantitative MRI
Authors: Nabbout Marianne , Langham Michael , Caporale Alessandra , Guo Wensheng , Wehrli Felix
Published: August 2024

To assess the acute effects of tobacco and electronic cigarette inhalation on vascular function, multiple MRI markers were analyzed in a study targeting peripheral, central and neurovascular beds of healthy young subjects. Smokers and vapers (9 subjects for a total N=15 study visits), ages 22 to 45 years, underwent two MRI scans, with a smoking or vaping challenge in between. Data from smoking/vaping challenges were combined to assess for their pooled effect. Smoking/vaping had significant acute effects on peripheral reactivity, notably on the superficial femoral artery flow-mediated dilation, baseline velocity and superficial femoral vein baseline oxygen saturation, among others.
Ferumoxytol Dose Optimization for 3D Whole-Heart Congenital Heart Disease Imaging
Authors: Dzelebdzic Sanja , Abadeer Maher , Greil Gerald , Hussain Tarique
Published: August 2024

With its concomitant ability to shorten the T1 relaxivity of blood and long intravascular half-life, ferumoxytol has become a popular “blood pool” contrast agent. The optimum contrast dose is not known. Reducing the ferumoxytol dose to 2 mg/kg is an efficient method to optimize the image quality, diagnostic performance, and achieve reduction in Gibbs’ truncation artefact.
Investigation of the effect of deep-breathing on the caval circulation in patients with cardiac rhythm disorders using 5D radial Flow MRI
Authors: Boccalini Sara , Beghella Marta , Boussel Loic , Douek Philippe , Chevalier Philippe , Prieto Claudia , Sigovan Monica
Published: August 2024

Respiratory motion effects thoracic blood flow mainly by intrathoracic pressure changes. In addition, deep-inspirations strongly increase the systemic venous return with immediate repercussions on right ventricular stroke volume. Simultaneously, pulmonary resistance is increased leading to decreased inflow in the left chambers, which is compensated in the following heartbeats. In patients with atrial myopathy (ex. atrial fibrillation), these adjustments might be more difficult. Our aim was to assess the impact of deep breathing on hemodynamic parameters in patients with atrial fibrillation, paroxysmal and permanent, and in a healthy population as compared to normal breathing.
An empirical approach to determine water T1 from multiparametric MR images of the liver
Authors: Michelotti Filippo , Kupriyanova Yuliya , Mori Tim , Küstner Thomas , Heilmann Geronimo , Bombrich Maria , Moeser Clara , Schön Martin , Roden Michael , Schrauwen-Hinderling Vera
Published: August 2024

This work focuses on an empirical approach to determine water T1 from multiparametric MR images, including T1, PDFF and T2* maps. To this end, a multiple linear regression model was fit to describe the deviation in MOLLI T1 based on PDFF and T2* values, which were measured in phantoms built at increasing lipids and iron content. This method was validated on a cohort of healthy volunteers and diabetes subjects (n=45). Further investigations were conducted to elucidate the relationship between MOLLI T1 values, before and after correction for hepatic lipid and iron content, and liver stiffness measured by MR elastography.
New semi-quantitative contrasts can approximate R1 and R2 in clinical setting
Authors: Moskovich Shachar , Shtangel Oshrat , Mezer Aviv
Published: August 2024

Weighted MRI images are widely used in both clinical and open-source datasets, while quantitative mapping is not always feasible. The ratio of T1 and T2 weighted images was previously suggested as a semi-quantitative measurement. We propose two additional weighted ratios T1w/PDw and ln(T2w/PDw), as semi-quantitative proxies for R1 and R2, which we tested on phantom and human data. We found that the new ratios accurately represent the quantitative parameters in both datasets.
Separation of type and grade in cervical tumors using MOLLI T1 mapping and non-mono-exponential models diffusion-weighted MR imaging
Authors: Li Shujian , Lin Jieliang , Cheng Jingliang
Published: August 2024

This study conducted an initial investigation of the feasibility of MOLLI-based T1 mapping and DWI by using mono-exponential, bi-exponential, and DKI models for the noninvasive preoperative evaluation of cervical cancer. Our findings indicated that both T1 mapping and non-mono-exponential model DWI can be used to discriminate cervical cancer from normal cervical tissue and adenocarcinoma from SCC. Our results also achieved a significant information gain for identifying SCC grade by combining native T1 and MKmean. Moreover, the maximum or minimum values of diffusion parameters within the whole lesion had advantages over the mean values in the prediction of SCC grade.
Water-Specific T1 Mapping of the Liver: The Influence of R2* Estimation and Number of Echoes
Authors: Li Zhitao , Xia Ding , Vasanawala Shreyeas , Feng Li
Published: August 2024

Fat represents a major confounding factor for T1 mapping of the liver. Recently, a number of novel magnetization-prepared multiecho imaging approaches have been proposed to obtain water-only T1 mapping, and they all hold great potential for clinical applications. However, several questions have raised along with this this trend, such as (1) whether concurrent estimation of R2star and the number of echoes is necessary and whether it would affect the quantification of water T1; and (b) whether the number of echoes would affect T1 estimation. This work aimed to investigate these two questions with both numerical simulation and in-vivo experiments.
Initial Demonstration of Simultaneous Estimation of Water-Specific T1, PDFF, R2*, and QSM in the Liver Using Free-Breathing GraspT1-Dixon MRI
Authors: Chen Jingjia , Xia Ding , Block Kai Tobias , Liu Chunlei , Feng Li
Published: August 2024

This work demonstrates the feasibility of simultaneous estimation of fat/water-separated T1, proton density fat fraction (PDFF), R2*, and quantitative susceptibility mapping (QSM) of the liver using free-breathing GraspT1-Dixon MRI from a single rapid acquisition with an inversion-recovery (IR)-prepared multi-echo stack-of-stars sequence. For fat/water-separated T1 mapping, water-only images are generated from multi-echo images at different inversion times (TIs), from which a water-specific T1 map is estimated. For other parameters, acquired data from all TIs are averaged to generate a single set of multi-echo images, from which PDFF, R2*, and QSM are estimated.
Bayesian Networks Reveal the Interplay Between Quantitative Liver MRI Metrics
Authors: Wang Yi-Chun , Salvati Roberto , Connell John , Van Zijl Natali , Waddell Tom , Bulte Daniel , Brady Michael
Published: August 2024

Understanding the interplay between quantitative MRI metrics is crucial for reliable clinical assessment of liver health. This study utilised Bayesian networks to visualise hidden relationships between cT1, T2*, proton density fat fraction (PDFF), volume and future liver remnant (FLR). Analysing the directionality between Bayesian networks on a pre-operative dataset with 130 participants and a post-operative dataset with 90 participants, clear causal relationships from PDFF to cT1 and from PDFF to volume were found, which are supported by published literature. An additional discovery is the potential for correlation between metrics to help strengthen the clinical utility of cT1 after surgery.
Nine-Fold Acceleration of Multi-Parametric Imaging of the Brain through Joint Sparsity regularized Wave-SPIRiT reconstruction
Authors: Jia Sen , Zou Lixian , Qiu Zhilang , Ye Yongquan , Wang Haifeng , Zou Chao , Li Ye , Xu Jian , Liu Xin , Zheng Hairong , Liang Dong
Published: August 2024

The MULTIPLEX technique could quantify the T1/T2*/PD/Susceptibility maps in a single 3D scan but leads to a long scan time due to the dual-TR, dual-flip angle, and multi-echo signal acquisition strategy. Wave-CAIPI acceleration with SENSE reconstruction is limited by noise amplification at high acceleration factors and is susceptible to artifacts from inaccurate coil sensitivity maps. This work develops a L1 regularized Wave-SPIRiT reconstruction to achieve 9-fold accelerated MULTIPLEX imaging in 3 minutes. The L1 regularized coil-by-coil reconstruction also benefits the Multi-Dimensional Integration (MDI) quantification to achieve comparable accuracy and robustness as the reference scan with 55% reduction of scan time.
Utilization of an MRI compatible loading device for the evaluation of unloaded-to-loaded changes in region specific tibial cartilage T1ρ and T2:
Authors: Argentieri Erin , Zhu Andrew , Wach Arden , Pekmezian Ashley , Bansal Sonia , Breighner Ryan , Potter Hollis , Maher Suzanne , Koff Matthew
Published: August 2024

Evaluation of unloaded-to-loaded changes within cartilage revealed that tibial cartilage thickness, T1ρ, and T2 metrics all decreased/shortened following application of 50% BW axial load. Shortening of loaded qMRI values is likely attributed to water loss from the cartilage matrix due to PG/matrix damage and attendant loss of cartilage FCD within this cadaveric model. As both the static and dynamic responses of cartilage to load are impacted by degeneration, quantification of unloaded-to-loaded T1ρ and T2 values may provide additional insight into cartilage health. Future work will evaluate unloaded-to-loaded cartilage T2* metrics to better elucidate movements of free and bound water pools.
Quantitative T2 Mapping of Articular Cartilage in Patients with Posterior Horn Root Tears of Medial Meniscus
Authors: Kajabi Abdul Wahed , Zbyn Stefan , Smith Jesse , Homan Morgan , Abbasguliyev Hasan , Rodriguez Ariel , Metzger Gregory , LaPrade Robert , Ellermann Jutta
Published: August 2024

The aim of this study was to evaluate degenerative changes in articular cartilage of patients with posterior root tear of the medial meniscus. Multi-echo quantitative T2 mapping was acquired on a 7T clinical scanner. For reference, age- and gender-matched healthy controls were scanned using the same 7T protocol. Arthroscopic evaluation of articular cartilage and menisci was performed in patients during the repair of posterior medial root tears. Significantly higher T2 values were found in the lateral and medial femoral cartilage of the patients compared to healthy controls.
Direct visualization of small anisotropic brain structures using high resolution, multi-shell diffusion MRI
Authors: Ades-Aron Benjamin , Stepanov Valentin , Coelho Santiago , Mogilner Alon , Novikov Dmitry , Shepherd Timothy , Fieremans Els
Published: August 2024

In vivo visualization and quantitative assessment of small anisotropic brain structures is challenging with diffusion MRI because of signal-to-noise limitations. We show that direct visualization of small structures, like the fornix or stria medullaris, dramatically improves using denoised 1-mm isotropic resolution complex-valued dMRI data. This approach also reduces the bias and variance of diffusion parameter estimations for small structures. Increased resolution with denoising decreases parameter variance due to thermal noise and partial volume effects – these data also can be used to better estimate the true biological variance in a structure by extrapolating the data to the infinite SNR limit.
3D volumetric myelin water phase mapping via short-TR adiabatic inversion recovery (STAIR) MRI
Authors: Shin Soo Hyun , Moazamian Dina , Lo James , Jang Hyungseok , Carl Michael , Chang Eric , Du Jiang , Ma Yajun
Published: August 2024

Demyelination is a common hallmark of neurodegenerative diseases such as multiple sclerosis. Thus, selective imaging of myelin will greatly enhance the diagnosis of such diseases. Here, we demonstrate the feasibility of acquiring whole-brain 3D myelin water phase maps via short-TR adiabatic inversion recovery (STAIR) MRI. The phase of proton density-weighted (PD) images was subtracted from the phase of STAIR images to remove the background field. The overall positive frequency shift, with a larger shift in the splenium of the lower slice, matches the white matter fiber orientation.
Adults with hypertension exhibit lower cerebral myelin content.
Authors: Laporte John , Faulkner Mary , Gong Zhaoyuan , Alsameen Maryam , Akhonda Mohammad , Triebswetter Curtis , Kiely Matthew , Bouhrara Mustapha
Published: August 2024

Hypertension is a major risk factor for a myriad of neurodegenerative diseases. However, the effect of hypertension on cerebral microstructure, especially myelination, remains poorly understood. We employed multicomponent MR relaxometry and DTI to investigate the association between hypertension and cerebral microstructural integrity, with a focus on myelin content, in a cohort of cognitively unimpaired adults. Our results indicate that adults with hypertension exhibit significantly lower cerebral microstructural integrity and axonal myelination as compared to controls across, several white matter structures.
Mapping the myelin bilayer with short-T2 MRI: Translation to in vivo application
Authors: Baadsvik Emily Louise , Weiger Markus , Froidevaux Romain , Schildknecht Christoph , Ineichen Benjamin , Pruessmann Klaas
Published: August 2024

Direct access to myelin content through the detection of signals from the myelin lipid-protein bilayer can be achieved using advanced short-T2 techniques. Here, we translate an existing procedure for mapping the myelin bilayer ex vivo to in vivo human application. Myelin maps are generated by fitting a three-component complex model to multi-TE (20–800µs) data acquired using the HYFI variant of the zero-TE sequence. The presented myelin maps exhibit expected white/grey matter contrast and are of reasonable quality. The step to in vivo represents an important advancement for myelin bilayer mapping as a promising emerging technique.
Measuring water exchange in myelinated white matter using Magnetization Transfer (MT)-weighted constant gradient diffusion MRI (MT-cgdMRI)
Authors: Li Chenyang , Fieremans Els , Novikov Dmitry , Zhang Jiangyang
Published: August 2024

In white matter, myelin forms a barrier for water exchange between the intra-axonal and extra-axonal compartments. Although myelin is not directly visible in conventional diffusion MRI (dMRI), it may affect dMRI measurements via exchange. In this study, we compared two ways to combine magnetization transfer (MT) preparation with constant gradient dMRI (cg-dMRI) to study the effects of myelin on water exchange rate. Our results demonstrate that MT preparation can modulate the sensitivity of cg-dMRI to exchange by suppressing signals from a portion of exchanging spins and that placing MT preparation is more effective before diffusion encoding than during diffusion encoding.
Component Analysis based on Standard-deviation Attenuation (CASA): a new algorithm for the denoising of Diffusion MRI data
Authors: Zucchelli Mauro , Papageorgakis Christos , Casagranda Stefano
Published: August 2024

Noise is a crucial problem that affects even the most advanced MRI techniques based on model fitting. It is therefore important to act on the raw data to remove as much noise as possible, while preserving the anatomical structures. Many techniques based on Principal Component Analysis (PCA) take advantage of the redundancy of information contained in multiphase data, to perform robust denoising. In this work, we introduce a new denoising method based on PC images. We show the added value of our technique on both the raw data and the derived fractional anisotropy map.
A data-driven paradigm for myelin water imaging – validation on multicompartment phantom and multiple sclerosis patient
Authors: Zlotzover Sharon , Omer Noam , Stern Neta , Radunsky Dvir , Blumenfeld-Katzir Tamar , Ben-Eliezer Noam
Published: August 2024

Multicomponent (MC) T2 analysis is a common technique for probing sub-voxel compartmentation in myelinated tissues. However, the task of resolving the T2 spectra from a single voxel is ill-posed and highly sensitive to noise. Applying a spatially-global MC analysis of the tissue prior to the voxel-wise analysis promotes more stable solutions. Specifically, this approach identifies a specific set of MC T2 features which are then used for fitting the signal in each voxel. Preliminary results suggest that the new data-driven approach can accurately estimate myelin content and correctly estimate myelin content in healthy tissue and in multiple sclerosis lesions.
Assessing microstructural and microvascular abnormalities in hospitalized COVID-19 patients using intravoxel incoherent motion imaging
Authors: van der Knaap Noa , Klinkhammer Simona , Postma Alida , Slooter Arjen , Horn Janneke , van Heugten Caroline , Voorter Paulien , van der Thiel Merel , Drenthen Gerhard , Backes Walter , Linden David , Ariës Marcel , Jansen Jacobus
Published: August 2024

Cerebral abnormalities are common in (severely affected) COVID-19 patients, although most reports only cover macrostructural abnormalities. Zooming in on microstructural abnormalities may better explain persisting COVID-19-related symptoms in COVID-19 survivors. Using intravoxel incoherent motion (IVIM) imaging, this study explored potential differences in microstructural and microvascular diffusivity between COVID-19 patients. No differences were found between patients admitted to the intensive care unit (ICU) (n=40) and general ward (n=38). However, increased disease severity in COVID-19 ICU patients was found to be associated with increased interstitial fluid content in the normal appearing white matter.
Quantitative diffusion and Kurtosis MRI in the evaluation of endometrial cancer: validation with histopathology
Authors: Maiuro Alessandra , Di Stadio Francesca , Satta Serena , Perniola Giorgia , Palaia Innocenza , Pernazza Angelina , Rocca Carlo Della , Catalano Carlo , Manganaro Lucia , Capuani Silvia
Published: August 2024

To ameliorate the Endometrial cancer (EC) diagnosis and prognosis, IVIM and KURTOSIS models were used to elaborate DWIs obtained from 18 with EC and 20 healthy women. The b-values were 0,30,50,150,500,800,1000,1500,2000,2500s/mm2. DWIs were noise-corrected considering a homomorphic approach. For each EC subject, ROI in the tumor (T) and peritumoral (PT) area were analysed and endometrial area in healthy (H) subjects was also obtained. IVIM and Kurtosis parameters were quantified. K, which quantifies tissue’s complexity, is significantly higher in T and PT than in H. f is higher in PT compared to the other areas, highlighting the perfusive nature of EC.
Widespread, depth-dependent microstructural damage in the cortex of children with focal epilepsy: A quantitative T1 and T2 mapping study
Authors: Casella Chiara , Vecchiato Katy , Cromb Daniel , Guo Yourong , Hughes Emer , Dillon Louise , Green Elaine , Colford Kathleen , Price Anthony , Grande Lucilio Cordero , Wood Tobias , Malik Shaihan , Teixeira Rui Pedro , Carmichael David , O'Muircheartaigh Jonathan
Published: August 2024

We assessed cortical microstructure in children with drug-resistant focal epilepsy using T1 and T2 relaxometry (qT1 and qT2). We show widespread, depth-mediated qT1 and qT2 increases, and alterations in intracortical organisation in patients. Changes did not correlate with clinical parameters, suggesting that they may be independent of disease severity. Using a random forest algorithm, we also show that qT1 and qT2 surface-features from patients with radiologically defined abnormalities (MRI-positive) and controls, can classify patients without reported radiological abnormalities (MRI-negative). This suggests a common imaging endophenotype of focal epilepsy irrespective of visible abnormalities that may be present at a pre-symptomatic disease-stage.
Image-Space Self-Navigation for Respiratory Motion Compensation in 2D Axial Radial Free-Breathing MRE of the Liver
Authors: Delgado Timoteo , Kafali Sevgi , Shih Shu-Fu , Adamos Timothy , Ghahremani Shahnaz , Calkins Kara , Zhong Xiaodong , Deshpande Vibhas , Bolster Bradley , Wu Holden
Published: August 2024

Previous work has proposed self-navigated golden-angle (GA) radial free-breathing (FB) MR elastography (MRE) of the liver. This work employed a standard DC-based motion compensation framework that proved suboptimal. Here we propose an image-space based motion-compensation framework for 2D free-breathing radial MRE. The proposed method is compared to the standard DC-based method by measuring the signal-to-noise (SNR) after self-navigated motion-compensation by each method (8 subjects). The median (interquartile range) SNR across subjects was 4.8 (3.6-5.7) and 6.8 (6.3-7.5) for the standard and proposed methods, respectively. Inclusion of image-space data may allow for more robust motion compensation for 2D radial axial acquisitions.
Automatic coil selection to suppress motion artifacts in exercise real-time cine imaging
Authors: Chen Chong , Liu Yingmin , Ding Yu , Tong Mathew , Han Yuchi , Ahmad Rizwan
Published: August 2024

We propose a novel method to automatically identify and discard coils that strongly contribute to image artifacts. This is achieved by projecting coil images to the space spanned by the ESPIRiT coil sensitivity maps. The proposed method is evaluated using the real-time cine data collected from twelve volunteers during exercise. The artifacts in the reconstructed real-time cine images are suppressed significantly with the proposed coil selection method.
Optimized Flow Compensation for Wave-CAIPI Post-Contrast 3D-T1 MPRAGE
Authors: Lang Min , Tabari Azadeh , Awan Komal , Liu Wei , Bryan Clifford , Lo Wei-Ching , Splitthoff Daniel , Cauley Stephen , Susie Huang , John Conklin
Published: August 2024

Flow-related artifacts have been consistently observed in highly accelerated Wave-CAIPI post-contrast 3D-T1 MPRAGE and have an atypical appearance. Such artifacts introduce a diagnostic conundrum as they can mimic enhancing lesions and may require callback for repeat imaging, posing a critical barrier to wider clinical adoption of this technique. To address this, we developed an optimized flow-mitigated Wave-CAIPI post-contrast 3D T1 MPRAGE acquisition, tested it in a novel flow phantom, and deployed it in 17 patients undergoing contrast-enhanced brain MRI. Flow-mitigation was successful at reducing flow-related artifacts in most cases without sacrificing SNR, gray-white matter contrast, or enhancing lesion conspicuity.
Dynamic field correction for improved susceptibility weighted imaging with FID-navigated 3D EPI
Authors: Utkur Mustafa , Wallace Tess , Kober Tobias , Jaimes Camilo , Warfield Simon , Kurugol Sila , Afacan Onur
Published: August 2024

3D EPI is a clinically promising alternative for susceptibility weighted imaging due to multi-shot acceleration. However, achieving submillimeter resolution with 3D EPI is challenging as shot-to-shot B0 variations result in artifactual images that limit detection of small veins which can be decisive for detection of the central vein sign in multiple sclerosis. FID navigators have been shown to estimate phase drifts in EPI sequences. We demonstrate that FID-navigated 3D EPI acquisitions enable correction for phase-induced distortions and achieve high-quality submillimeter-resolution susceptibility weighted images.
Using SMASH Spatial Harmonics to Slice-Encode Outflow Artefacts in bSSFP Imaging
Authors: Ali Fadil , Finn John , Bydder Mark
Published: August 2024

In the present of through plane flow in 2D bSSFP imaging, we used the variation coil sensitivity profile along the through-slice direction to estimate the spatial harmonics needed to slice-encode for outflowing spins. Estimating the outer partitions unfolded the outflowing spins from the target center slice with a faster acquisition time than our previous slice-encoding technique.
AI-Assisted Iterative Reconstruction for CMR Multitasking
Authors: Chen Zihao , Lee Hsu-Lei , Xie Yibin , Li Debiao , Christodoulou Anthony
Published: August 2024

CMR Multitasking is a promising approach for quantitative imaging without breath-holds or ECG monitoring but standard iterative reconstruction is too long for clinical use. Supervised artificial intelligence (AI) can accelerate reconstruction but lacks generalizability and transparency, and T1 mapping precision has not been sufficient. Here we propose an AI-Assisted Iterative (AAI) reconstruction which takes an AI reconstruction output as a “warm start” to a well-characterized iterative reconstruction algorithm with only 2 iterations. The proposed method produces better image fidelity and more precise T1 maps than other accelerated reconstruction methods, in less than 15 seconds (16x faster than conventional iterative reconstruction).
Temporal-Structural Graph Convolutional Network for Knee Osteoarthritis Progression Prediction Using MRI from the Osteoarthritis Initiative
Authors: Hu Jiaping , Zhou Zidong , Peng Junyi , Zhong Lijie , Jiang Kexin , Zhang Zhongping , Lu Lijun , Zhang Xiaodong
Published: August 2024

Identifying patients with knee osteoarthritis (OA) whom the disease will progress is critical in clinical practice. Currently, the time-series information and interactions between the structures and sub-regions of the whole knee are underused for predicting. Therefore, we propose a temporal-structural graph convolutional network (TSGCN) using time-series data of 194 cases and 406 OA comparators. Each sub-region was regarded as a vertex and represented by the extracted radiomics features, the edges between vertexs were established by the clinical prior knowledge. The multiple-modality TSGCN (integrating information of MRIs, clinical and image-based semi-quantitative score) performed best comparing to the radiomics and CNN model.
DSC-derived perfusion map generation from DCE MRI using deep learning
Authors: Pei Haoyang , Lyu Yixuan , Lambrecht Sebastian , Lin Doris , Feng Li , Liu Fang , Nyquist Paul , Zijl Peter , Knutsson Linda , Xu Xiang
Published: August 2024

This study built a deep-learning-based method to directly extract DSC MRI perfusion and perfusion related parameters from DCE MRI. A conditional generative adversarial network was modified to solve the pixel-to-pixel perfusion map generation problem. We demonstrate that in both healthy and brain tumor patients, highly realistic perfusion and perfusion related parameter maps can be synthesized from the DCE MRI using this deep-learning method. In healthy controls, the synthesized parameters had distribution similar to the ground truth DSC MRI values. In tumor regions, the synthesized parameters correlated linearly with the ground truth values.
Associations Between Central Canal Stenosis, Resting State Functional Connectivity Networks, and Pain Perception
Authors: Cummings Jennifer , Hess Madeline , Gao Kenneth , Bharadwaj Upasana , Han Misung , Chin Cynthia , Torrisi Salvatore , Townsend Jennifer , Vu An , Pedoia Valentina , Majumdar Sharmila
Published: August 2024

Chronic lower back pain remains difficult to characterize with imaging. With this study, we investigate the relationship between imaging-based brain and spine biomarkers in pain perception. We present relationships between resting state functional connectivity networks, automatic spinal canal stenosis grading, and patient-reported pain measures. Patients reporting severe pain show weaker connectivity in the Left Ventral Attention Network and stronger connectivity within the Salience network when compared to those reporting no pain or mild/moderate pain. The severe back pain group also shows a higher spinal canal stenosis grading.
Gender differences in brain response to infant emotional faces
Authors: Su Wei , Du Xiaoyu , Liu Xianling , Sun Zhenhua , Zhang Kaihua , Wang Mengxing , Du Xiaoxia
Published: August 2024

Exploring the neural processes of recognizing infant stimuli promotes better understandings of the mother-infant attachment mechanisms. Here combining Task-fMRI and resting-state fMRI investigated the effects of infants’ emotional faces on the brain activity of women and men. The task-fMRI showed that the brains of women and men reacted differently to infants’ faces, and these differential areas are in facial processing and empathetic networks. The rs-fMRI further showed that the connectivity of the default-mode network-related regions increased in women than men. These differences might facilitate women to more effective and quick adjustments in behaviors and emotions during the nurturing infant period.
Implementation of dissolved 129Xe lung MRI with 4-echo 3D radial spectroscopic imaging at 3T: comparing with results at 1.5T in healthy volunteers
Authors: Collier Guilhem , Chan Ho-Fung , Norquay Graham , Stewart Neil , Munro Ryan , Rodgers Oliver , Schulte Rolf , Wild Jim
Published: August 2024

Four-echo 3D radial spectroscopic imaging of hyperpolarised 129Xe in the lung is implemented at 3T to measure ratios of xenon gas and dissolved xenon in blood (RBC) and lung tissues (M). Thanks to an interleaved acquisition of the echo times and the choice of a 0.32ms echo time spacing, data acquisition is possible within the short relaxation time of dissolved 129Xe (T2*~1ms). 11 healthy volunteers have been imaged at both 1.5 and 3T after the inhalation of a 1L dose of hyperpolarised 129Xe. Results show comparable images at both field strengths and a significantly reduced (p=0.02) RBC:M at 3T.
Reproducibility of M1-optimized Liver DWI Across Field Strengths and Gradient Performance
Authors: Allen Timothy , Volety Srijyotsna , van der Heijden Rianne , Simchick Greg , Hernando Diego
Published: August 2024

Liver DWI using M1-optimized diffusion imaging (MODI) minimizes motion-induced signal dropout while suppressing lesion-mimicking vessel signal. However, early MODI implementations have been confined to 3.0T MR systems with high-performance gradients. The feasibility and reproducibility of MODI DWI on 1.5T systems and systems with conventional gradient performance remains untested. In this work, liver DWI was acquired using conventional and MODI acquisitions in 8 healthy human subjects on 3 separate MR systems with different field strength and gradient performance. ADC estimation with MODI achieved smaller coefficients of variation and reproducibility coefficients across MR systems in comparison to conventional Stejskal–Tanner (monopolar) DWI.
Multiparametric MR imaging to identify the changes in normoalbuminuric diabetic kidney disease (NADKD) noninvasively
Authors: Yamamoto Akira , Tamada Tsutomu , Ueda Yu , Kido Ayumu , Higaki Atsushi , Kanki Akihiko , Fukukura Yoshihiko
Published: August 2024

This study suggests the possibility that MRI using the values of CMD on optimal TI on SSFP with IR pulse with multi TI, which can sensitively capture fibrotic changes in the renal cortex of NADKD, can be a new parameter to evaluate NADKD non-invasively and in a short period of time.
The value of amide proton-weighted imaging and diffusion kurtosis imaging in predicting Her-2 expression in endometrial cancer
Authors: Li Xiwei , Tian Shifeng , Ma Changjun , Wang Nan , Wang Jiazheng , Liu Ailian
Published: August 2024

Endometrial cancer (EC) is one of the three major malignant tumors in women, and its commonly used treatment is mainly surgery, radiotherapy, chemotherapy and hormone therapy. However, some patients still have low response to the above treatments. However, molecular therapy targeting Her-2 gene has significant value in the clinical diagnosis and improving the prognosis. Amide proton weighted imaging (APTw) and diffusion kurtosis imaging (DKI)can be used for the diagnosis of diseases by reflecting the level of molecular metabolism and cellular microstructure. This study explored the value of the above two sequences in quantitative prediction of HER-2 gene expression levels.