bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Accelerated T2 and Diffusion Weighted Imaging of the Prostate by Combining Compressed SENSE, Sparse Sampling and Deep Learning
Authors: Harder Felix , Weiss Kilian , Amiel Thomas , Peeters Johannes , Tauber Robert , Makowski Marcus , Sauter Andreas , Gschwend Jürgen , Karampinos Dimitrios , Braren Rickmer
Published: August 2023

Since prostate MRI is increasingly applied and yet limited by long acquisition times, we prospectively investigated the performance of a novel reconstruction algorithm, combining compressed sensing, parallel imaging and deep learning (C-SENSE AI) in patients with histologically proven prostate cancer. Highly accelerated T2w and DWI sequences were compared to clinical standard of reference T2w and DWI. C-SENSE AI enabled 58% acceleration in T2w imaging and 47% acceleration in DWI of the prostate while obtaining significantly better image quality and tumor detection. C-SENSE AI seems particularly interesting in view of the need for accelerated prostate MRI with preserved high image quality.
A multimodality, MRI positive-contrast fiducial marker for prostate cancer treatment: first-in-patient experience with proton therapy
Authors: Sanders Jeremiah , Wang Li , Poenisch Falk , Sahoo Narayan , Zhu Xiaorong , Ma Jingfei , Choi Seungtaek , Nguyen Quynh , Mok Henry , Tang Chad , Crabtree Katina , McGuire Sean , Hoffman Karen , Shah Shalin , Frank Steven
Published: August 2023

Carbon and gold fiducial markers (FMs) are the most commonly used FMs for prostate radiotherapy. However, these markers do not produce positive contrast on MRI, and can cause large magnetic susceptibility artifacts on MRI. These properties of carbon and gold FMs make their identification on MRI challenging and complicate treatment planning processes that use co-image registration of MRI with CT for radiotherapy treatments. A novel multimodality FM has been developed that produces positive contrast on four imaging modalities, including MRI. This work presents the first-in-patient experience using the multimodality FM for proton therapy of prostate cancer.
Transrectal magnetic resonance imaging and robot- guided focal laser ablation of prostate cancer: preliminary results of a phase 2 study.
Authors: Van Luijtelaar Annemarijke , Sedelaar J.P. Michiel , Bomers Joyce , Fütterer Jurgen
Published: August 2023

Magnetic resonance imaging-guided focal laser ablation is used as alternative to radical treatment while preserving healthy tissue and subsequently reduce treatment-related morbidity in patients with localized prostate cancer. Preliminary results of this prospective, non-randomized, clinical phase 2 study using a remote-controlled manipulator, show promising results in both oncological and functional outcomes in a group of 20 patients with low- to intermediate-risk (Gleason Score ≤ 4+3) prostate cancer. Transrectal magnetic resonance imaging-guided focal laser ablation is a promising outpatient procedure under local anesthesia for localized prostate cancer. It provides a fast and minimally-invasive strategy while reducing treatment related complications and side-effects.
Application of Super-Paramagnetic Iron Oxide Nanoparticle to improve tumor visualization for MR-guided liver SBRT using Elekta Unity MR-Linac
Authors: Lee Danny , Oh Seungjong , Hwang Min-sig , McCauley Mary , Pavord Daniel , Yun Kyung Lim , Sohn Jason , Kirichenko Alexander
Published: August 2023

Ablative SBRT to liver malignancies on MRI-Linac is a novel and rapidly evolving technology allowing visualization of tumor and nearby organs at risk (OAR). Reliable identification of liver tumors has direct impact on radiotherapy planning and outcome. SPION agent Ferumoxytol® (Feraheme, AMAG Pharmaceuticals, Waltham, MA) was applied as MRI contrast during adaptive planning on Elekta Unity MR-Linac. Compared to the non-contrast images, liver tumors after Ferumoxytol® injection, were superiorly visible for accurate delineation during the entire treatment course. This study is the first to report the impact of SPION contrast agent on liver tumor visualization in a 1.5T Elekta MR-Linac.
Distortion- and ghosting-free high b-value ex vivo human brain diffusion MRI achieved with spatiotemporal magnetic field monitoring
Authors: Ramos-Llorden Gabriel , Park Daniel , Mirkes Christian , Cushing Cameron M. , Weavers Paul , Lee Hong-Hsi , Tian Qiyuan , Scholz Alina , Keil Boris , Bilgic Berkin , Yendiki Anastasia , Witzel Thomas , Huang Susie Y.
Published: August 2023

Whole brain ex vivo diffusion MRI needs high b-value encoding to compensate for the reduced diffusivity, requiring human brain scanners with ultra-strong diffusion gradients. At that regime, eddy currents become too severe, to the point image distortions and ghosting artifacts cannot be enough mitigated with conventional image reconstruction and post-processing approaches. On a 3T Connectom scanner , we demonstrate the importance of spatiotemporal field monitoring to measure and model eddy currents. When Fourier reconstruction is informed with the unwanted spatiotemporal evolution of the phase, distortion- and ghosting-free high-resolution DW images can be achieved.
Top-up algorithm for single k-space from single-shot EPI
Authors: Hwang Seon-Ha , Lee Hyun-Soo , Choi Seung Hong , Park Sung-Hong
Published: August 2023

Top-up algorithm requires two EPI images with opposite gradient polarities to make one corrected image. Here, top-up algorithm with a single k-space is proposed for single-shot pseudo-centric EPI, where a k-space can be separated into two halves with opposite distortions. A field map could be estimated by applying top-up algorithm to the two halves. The estimated map compensated the distortions well while preserving inner brain structures. The proposed approach provided 1.8 times higher perfusion SNR than conventional linear EPI. The approach is promising for magnetization-prepared imaging that requires high SNR, high temporal resolution, and minimal distortion with no additional scan.
Real-time shimming using FID navigators
Authors: Wallace Tess , Kober Tobias , Stockmann Jason , Polimeni Jonathan , Warfield Simon , Afacan Onur
Published: August 2023

Real-time B0 shimming enables improved compensation for the effects of dynamic field perturbations in MRI compared to retrospective approaches, which are computationally intensive and cannot compensate for inherent losses of information. FID navigators can rapidly characterize spatiotemporal field changes using a forward model that predicts the effect of B0 shim changes on the measured FID signal, making them ideally suited for real-time applications. In this work, we implement real-time field control using FID navigators to compensate for spatially linear field changes and demonstrate substantially improved T2*-weighted image quality in the presence of field perturbations in three volunteers scanned at 3T.
Ultrashort Echo Time Double Echo Steady State (UTE-DESS) Imaging with Eddy Current Compensation
Authors: Jang Hyungseok , Athertya Jiyo , Ma Yajun , Lombardi Alecio , Jerban Saeed , Chung Christine , Chang Eric , Du Jiang
Published: August 2023

The double echo steady state (DESS) sequence has been investigated extensively due to its short scan time and flexible image contrast achieved from a combination of a free induction decay (FID)-like S+ signal and simulated echo-based S- signal. Ultrashort echo time-based DESS (UTE-DESS) has recently been proposed for imaging of short T2 tissues in the human knee joint, but the effect of eddy currents in this technique has not yet been investigated. In this study, we demonstrate the effects of B0 and linear eddy current and elucidate the importance of eddy current compensation (ECC) for reliable UTE-DESS imaging.
MRSI spectral quantification using linear tangent space alignment (LTSA)-based manifold learning
Authors: Ma Chao , El Fakhri Georges
Published: August 2023

Spectral quantification is a critical step in quantitative MRS/MRSI. The recently proposed subspace-based spectral quantification method represents the spectral distribution of each model as a subspace model and enables effective use of spatiospectral priors to improve parametric estimation. However, modeling spectral distribution of each metabolite as a separate subspace leads to a large number of unknowns, which renders the resultant parametric estimation problem challenging when SNR is low. To address this issue, we propose a new linear tangent space alignment-based method for MRSI quantification, leveraging the intrinsic low-dimensional structure information of the underlying MRSI signals for improved parametric estimation.
T1-weighted ZTE MRI with phase-modulated RF and a parallel imaging, inverse problem-based reconstruction
Authors: Ramachandran Shreya , Lustig Michael
Published: August 2023

For fast T1-weighted imaging, zero echo time (ZTE) imaging provides rapid sampling of 3D k-space, but lacks T1 contrast due to its small flip angle excitation with short hard pulses. To efficiently increase T1 contrast, longer phase-modulated pulses can be used. However, longer pulses lead to larger dead-time gaps and pulse profile-weighted images. Here, we formulate an inverse problem to directly reconstruct profile-compensated images from multi-coil data without any intermediate step for dead-time infilling. We demonstrate that leveraging coil sensitivities and alternating phase-modulated excitations sufficiently condition the inverse problem, allowing for iterative reconstructions of T1-weighted acquisitions.
Learning compact latent representations of signal evolution for improved shuffling reconstruction
Authors: Arefeen Yamin , Xu Junshen , Zhang Molin , White Jacob , Bilgic Berkin , Adalsteinsson Elfar
Published: August 2023

Applying linear subspace constraints in the shuffling forward model enables reconstruction of signal dynamics through reduced degrees of freedom. Other techniques train auto-encoders to learn latent representations of signal evolution to apply as regularization. This work inserts the decoder portion of an auto-encoder directly into the shuffling forward model to reduce degrees of freedom in comparison to linear techniques. We show that auto-encoders represent fast-spin-echo signal evolution with 1 latent variable, in comparison to 3-4 linear coefficients. Then, the reduced degrees of freedom enabled by the decoder improves reconstruction results in comparison to linear constraints in simulation and in-vivo experiments.
Ex vivo gray matter is complex: exchange & disorder exponents
Authors: Jelescu Ileana , Uhl Quentin
Published: August 2023

Fixation alters tissue properties significantly and in vivo vs ex vivo models should be adapted accordingly. Unlike in vivo studies of rodent gray matter (GM) where diffusion time-dependence D(t) was absent for t > 10 ms, allowing an interpretation of time-dependent kurtosis K(t) as resulting from inter-compartment exchange, here we show that ex vivo rodent GM displays marked D(t), with non-Gaussianity arising most probably from extracellular water. K(t) could thus result from combined effect of disorder and exchange. High-b data where extracellular water is preferentially suppressed may still enable the unconfounded estimation of exchange.
The relation between brain anatomy, functional connectivity, and emotional behavior in 3- and 9-month old infants
Authors: Banihashemi Layla , Schmithorst Vanessa , Bertocci Michele , Samolyk Alyssa , Santos Joao , Versace Amelia , Taylor Megan , English Gabrielle , Northrup Jessie , Lee Vincent , Stiffler Richelle , Aslam Harris , Panigrahy Ashok , Hipwell Alison , Phillips Mary
Published: August 2023

Uncinate fasciculus, forceps minor, and cingulum bundle volumes measured in infants at 3 months of age via DWI tractography were found to predict infant emotionality at 3 months and 9 months of age. These relations were found to be mediated and/or suppressed by functional connectivity from the orbitofrontal cortex, dorsolateral prefrontal cortex, and posterior default mode. Therefore, modulating connectivity among regions in the default mode, central executive, and salience networks might be promising future approaches for interventions to maintain infant emotionality and reduce risk of future psychopathology later in childhood and adolescence.
Type 2 diabetes mellitus and obesity are associated with altered T2* and resting-state brain activity: a UK Biobank study
Authors: Jiang Guocheng , Swardfager Walter , Al-Ozairi Abdullah , Al-Ozairi Ebaa , Black Sandra , MacIntosh Bradley
Published: August 2023

T2*-weighted image is a versatile and common MR imaging readout. We studied anatomical and functional brain features in three groups: Type 2 diabetes mellitus (T2DM), obese, and healthy adults. We observed that T2DM and obese adults are associated with lower regional T2* relative to healthy adults. We further found that an adverse lipid profile in obese adults was associated with decreased regional brain intrinsic activity. This work helps to characterize how T2DM and obesity affects brain using susceptibility-weighted and resting-state functional MRI approaches.
Validation of Automated Topological LGE Thresholding for Peri-Infarct Substrate Characterization
Authors: Sheagren Calder , Escartin Terenz , Krahn Philippa , Patel Jaykumar , Guo Fumin , Wright Graham
Published: August 2023

High-resolution late gadolinium enhancement imaging is a powerful tool for arrhythmia risk assessment post-myocardial infarction, but requires substantial operator time and expertise to analyze. To address this challenge, automated analysis is introduced to isolate and depict relevant image features corresponding to healthy myocardium, peri-infarct gray zone, and dense scar. Using two sets of manual epicardial and endocardial contours, weighted total variation denoising is used to correct for statistical noise, and persistent homology is used to stratify topological features of the image. K-means clustering was used to generate remote myocardium and dense scar signal intensities for automated FWHM thresholding.
Increased Pulsatility Index of Perforating Arteries as Novel 7T Marker in Sporadic Cerebral Small Vessel Disease – Results of ZOOM@SVDs Study.
Authors: Pham Stanley , van den Brink Hilde , Arts Tine , Siero Jeroen , Hendrikse Jeroen , Zwanenburg Jaco , Biessels Geert Jan
Published: August 2023

We assessed blood-flow velocity measurements on 7T MRI as a potential disease marker for cerebral small vessel disease (SVD). Two-dimensional phase-contrast velocity measurements were performed in perforating arteries of the basal ganglia (BG) and white matter of the centrum semiovale (CSO) in patients with sporadic SVD and age- and sex-matched controls. Pulsatility index (PI) was significantly higher in the BG, in patients (0.45 [0.41–0.49] vs. 0.36 [0.30–0.41] in controls) (p=0.02). In the CSO, similar number of vessels, mean velocity, and PI were observed between patients and controls. BG pulsatility could be a potential marker for SVD.
Cerebral blood flow is associated with cerebral microstructural integrity in normative aging
Authors: Triebswetter Curtis , Kiely Matthew , Gong Zhaoyuan , Alsameen Maryam , Bouhrara Mustapha
Published: August 2023

Maintenance of cerebral tissue homeostasis is particularly sensitive to deficits in cerebral blood flow (CBF) and concomitant hypoxia and hypoglycemia. However, little work has been conducted to investigate the potential association between deficits in CBF and deterioration of brain microstructure, especially in normative aging. The results of our analysis, conducted on a large cohort of cognitively unimpaired adults, of the association between CBF and several MRI metrics of cerebral microstructural integrity, indicate that low CBF values correspond to low tissue integrity. These results provide further evidence of the intimate relationship between neurovascular physiology and brain integrity throughout normative aging.
Intracranial super-resolution 4D Flow MRI – using deep-learning to map flow and relative pressure in the brain
Authors: Marlevi David , Ferdian Edward , Schollenberger Jonas , Aristova Maria , Hardy Brandon , Edelman Elazer , Schnell Susanne , Figueroa C. Alberto , Nordsletten David , Young Alistair
Published: August 2023

Changes in regional hemodynamics are indicative of cerebrovascular disease. However, image-based monitoring is complicated by the unique flow and anatomies found in the brain, with accurate estimates requiring beyond state-of-the-art image resolutions. To address this, we combine a deep residual network, 4D Flow MRI, and physics-informed image processing to provide super-resolution flow images and coupled accurate quantification of intracranial relative pressure. The method is trained and validated on patient-specific in-silico data, highlighting how low resolution-biases are mitigated by super-resolution conversion. Data were also effectively generated at <0.5 mm in a representative in-vivo cohort, highlighting the potential of our presented approach.
Imaging hypoxia in murine oral cavity squamous cell carcinomas with oxygen-enhanced MRI
Authors: Roy Upasana , Lepicard Elise , Boult Jessica , Box Carol , Harrington Kevin , O’Connor James , Jamin Yann , Robinson Simon
Published: August 2023

Oxygen-enhanced (OE)-MRI was used to map and quantify hypoxia (pOxyR) in two murine models of oral cavity squamous cell carcinoma, a tumour type in which hypoxia adversely affects patient prognosis. OE-MRI relies on quantifying changes in the longitudinal MRI relaxation rate R1 induced by excess paramagnetic oxygen molecules dissolved in blood plasma and interstitial fluid with inhalation of oxygen. When combined with susceptibility-contrast MRI for determination of fractional blood volume and diffusion-weighted MRI to assess cellularity, OE-MRI enables an assessment of the spatial distribution and extent of tumour hypoxia, patent vasculature and necrosis.
First in-human technique translation of OE-MRI for hypoxia imaging onto an MR Linac system in patients with head and neck cancer
Authors: Dubec Michael , Datta Anubhav , Little Ross , Clough Abigael , Buckley David , Hague Christina , McHugh Damien , Berks Michael , Cheung Susan , Salah Amal , Higgins David , Eccles Cynthia , Bristow Robert , Naish Josephine , Matthews Julian , Hoskin Peter , van Herk Marcel , Parker Geoff , Choudhury Ananya , McPartlin Andrew , O'Connor James
Published: August 2023

Tumour hypoxia is associated with poor treatment outcome, tumour progression and treatment resistance. Oxygen-enhanced (OE)-MRI has shown promise as a non-invasive method for mapping and quantifying hypoxia. We demonstrate, for the first time, the application of the OE-MRI technique in patients with head and neck carcinoma to monitor changes in hypoxia due to treatment, and translate the technique onto an MR Linac system, demonstrating feasibility in a first-in-human study.
Super-fast and accurate estimation of relaxation and chemical exchange rate using 31P-MT-MR fingerprinting at 7T in the human brain
Authors: Widmaier Mark , Lim Song-I , Xin Lijing
Published: August 2023

In this abstract, we introduce 31P-MT-MRF, using a SAR efficient magnetization transfer (MT) approach. We extended the magnet resonance fingerprinting (MRF) framework to overcome obstacles of in vivo human brain 31P measurements. This abstract reports the reproducibility and robustness of 31P-MT-MRF estimations of the relaxation parameters of y-ATP and PCr as well as the chemical exchange rate kCK on healthy volunteers in vivo in human brain at 7T. We were able to demonstrate that our method is 3 times faster as state-of-the-art MT methods [6] and estimates are bias free enabling ultra-fast kCK measurement in 2:15 min scan time.
Through-plane diffusion MRI super-resolution with autoencoders: validation on outlier replacement scheme for pre-term baby brains
Authors: Kebiri Hamza , Canales-Rodríguez Erick , de Dumast Priscille , Taymourtash Athena , Lajous Hélène , Alemán-Gómez Yasser , Langs Georg , Cuadra Meritxell Bach
Published: August 2023

Although super-resolution diffusion MRI for isotropic volumes has been explored, to date no unsupervised SR techniques have been investigated for anisotropic dMRI. We propose an autoencoder based framework to enhance the through-plane spatial resolution and to replace slice outliers by leveraging existing high-quality datasets. Quantitative evaluation on 31 pre-term subjects show that the proposed framework significantly outperforms conventionally used interpolation methods at the raw data and estimated diffusion tensor maps. This can hence contribute to the depiction of more accurate white matter properties of the developing brain.
T2-deblurred deep learning super-resolution for turbo spin echo MRI
Authors: Chen Zihao , Xie Yibin , Li Debiao , Wu Yijen , Christodoulou Anthony
Published: August 2023

Deep learning MR super-resolution (SR) is a promising approach to reduce scan time without requiring custom sequences and iterative reconstruction. However, previous SR approaches are incompatible with turbo spin echo (TSE) sequence due to differences in T2 blurring effects between high-resolution and low-resolution TSE images. Here we propose a T2-deblurred deep learning SR model for 3x3 in-plane super-resolution of 3D TSE images. Our method accelerated scanning by 9x in both retrospective and prospective testing and provided better image quality than previous SR methods.
Changes in occipital GABA, glutamate/glutamine concentrations and cerebral oxygen metabolism in response to visual stimulation
Authors: Chan Kimberly , Lu Hanzhang , Lin Zixuan , Henning Anke , Thomas Binu
Published: August 2023

The relationship between brain’s GABA and glutamate/glutamine (Glx) concentrations measured by 1H MRS, hemodynamic response, neural signaling, and behavior is poorly understood. Here, the relationship between MRS-detectable GABA and Glx signals and MR hemodynamic contrasts during visual stimulation were examined. It was observed that changes in GABA+ and Glx were positively correlated with the BOLD response and negatively correlated with their levels at rest. Additionally, task GABA+ concentrations were negatively correlated with cerebral metabolic rate of oxygen (CMRO2). Together, these results suggest shifts in the inhibitory/excitatory balance and metabolism to maintain homeostasis in the brain.
Dynamic 13C MRS using 13C/1H Multichannel Coil as an Alternative to Imaging for Hyperpolarized Pyruvate Brain Studies
Authors: Ma Junjie , Pinho Marco , Harrison Crystal , Chen Jun , Reed Galen , Chen Albert , Sherry A. Dean , Malloy Craig , Madden Christopher , Park Jae Mo
Published: August 2023

This study demonstrates that time-resolved 13C MR spectroscopy with the multichannel 13C/1H RF coils can be performed as an alternative to imaging for assessing pyruvate metabolism using hyperpolarized [1-13C]pyruvate in the human brain.
Fat-Separated Radial 3D bSSFP Imaging at Low Field Using Frequency-Sweep RF Saturation and XD-GRASP Reconstruction
Authors: Zi Ruoxun , Chandarana Hersh , Block Kai
Published: August 2023

Low-field systems have recently gained interest because of the potential to make MRI more accessible, but the field reduction comes at expense of low SNR and challenges with fat suppression. This work describes a new concept for fat separation at low field, based on radial acquisition during frequency-sweep RF saturation and combined with frequency-resolved XD-GRASP reconstruction. The approach is demonstrated for free-breathing abdominal imaging using a radial stack-of-stars 3D bSSFP sequence at 0.55T, showing that fat and water can be reliably distinguished based on the response to saturation at different frequencies. Fat-suppressed composite images can be calculated as final step.
Assessment of Pulsatile Cerebrospinal Fluid Dynamics of the Human Brain using CArdiac-cycle Resolved Diffusion-weighted Imaging (CARDI)
Authors: Wen Qiuting , Tong Yunjie , Zhou Xiaopeng , Ho Chang , Wu Yu-Chien
Published: August 2023

We introduce an MRI technique named CARDI, for in-vivo assessment of pulsatile fluid dynamics in the surface paravascular spaces of the pial arteries. A pair of pulsed gradient spin echo was used to detect the slow flow of CSF while suppressing the fast flow of adjacent arterial blood. Waveform of CSF over a cardiac cycle is revealed. The shape of the CSF waveforms closely resembles the pressure waveforms of the artery wall, suggesting that CSF dynamics is tightly related to artery wall mechanics. The comparison of CSF waveforms in an aging group revealed a significant age-dependency of the CSF waveforms.
Contrast Agent Transport in Mouse Glymphatic System Observed by Dynamic Contrast-Enhanced MRI
Authors: Zhu Yuran , Gu Yuning , Kim Kihwan , Kolluru Chaitanya , Gao Huiyun , Wang Yunmei , Wilson David , Flask Chris , Yu Xin
Published: August 2023

This study compared the transport of three MRI contrast agents with different molecular sizes (Gd-DTPA, GadoSpin, and H217O) in the mouse glymphatic system with dynamic contrast-enhanced MRI. Dynamic signal changes in the whole-brain and selected regions of interest (ROI) were analyzed. The results showed drastically different kinetics of the three tracers, indicating differences in glymphatic transport routes and rates. The current work lays the foundation for future studies employing genetically manipulated mouse models for mechanistic understanding of the regulation of glymphatic function in normal and diseased conditions.
Quantitative imaging of brain to cerebrospinal fluid molecular clearance
Authors: Wåhlin Anders , Garpebring Anders , Mogensen Klara , Vikner Tomas , Björnfot Cecilia , Qvarlander Sara , Malm Jan , Eklund Anders
Published: August 2023

The pathways of brain molecular clearance and potential glymphatic efflux to extracerebral cerebrospinal fluid is a matter of intense research. We investigated possible contrast enrichment in cerebrospinal fluid of the subarachnoid space following intravenous contrast injection. This approach utilizes a subtle but widespread contrast leakage across the blood-brain barrier that potentially enables the investigation of glymphatic function. Using T1-mapping as well as dynamic scanning during contrast infusion, we present data consistent with a model where molecules cleared from the brain enter subarachnoid space cerebrospinal fluid. This approach could be a clinically feasible alternative for investigating brain molecular clearance in humans.
A 3D Dense-U-Net for fully automated 5D flow MRI segmentation
Authors: Ma Liliana , Berhane Haben , Baraboo Justin , Sugimura Michael , Roy Christopher , Falcão Mariana , Yerly Jérôme , Stuber Matthias , Markl Michael
Published: August 2023

Recently, a free-running 5D flow framework was introduced and validated. However, some 5D flow MRI is based on 3D radial imaging, which is limited by reduced SNR that can result in challenges with 3D segmentation. A number of previous studies have investigated automatic segmentation for 4D flow MRI, however these have been traditionally optimized for Cartesian datasets, which are typically acquired over much smaller spatial matrices and cover only one respiratory position. The purpose of this study was thus to adapt and expand a deep-learning framework to cardiac 5D flow MRI data for automatic segmentation of the thoracic aorta.
Pulmonary vein MRA with reduced sensitivity to off-resonance using optimized contrast preparation
Authors: Nagiub Mohamed , Ganigara Madhusudan , Sharma Bharti , Botnar René , Hussain Tarique , Greer Joshua
Published: August 2023

3D bSSFP is the standard for anatomical evaluation of congenital heart disease, but provides suboptimal visualization of the pulmonary veins due to off resonance and flow. Solutions have been proposed to reduce the sensitivity of the bSSFP acquisition to these factors with limited success. However, the T2prep pulse that is routinely applied for bSSFP imaging also likely contributes to pulmonary vein signal loss. In this study, we compare multiple contrast preparation schemes for 3D bSSFP imaging which minimize sensitivity of off-resonance to improve pulmonary vein visualization.
Enhanced superselective pseudo-Continuous Arterial Spin Labeling using parallel transmission with B1 phase shimming at 7T
Authors: Zhao Chenyang , Wang Kai , Wang Danny
Published: August 2023

Superselective pseudo-Continuous Arterial Spin Labeling (SS-pCASL) suffers from low labeling efficiency due to B1 inhomogeneity at 7T. An enhanced SS-pCASL using parallel transmission with B1 phase shimming was proposed. B1 phase shimming algorithm was designed to penalize low and high B1 amplitude in the labeled and unlabeled ICA, respectively. B1 amplitude was increased by 40% for the labeled ICA and decreased by 90% for the unlabeled ICA. Simulation and in-vivo results demonstrated that enhanced SS-pCASL improved labeling efficiency for the labeled ICA and suppressed labeling oscillation for the unlabeled ICA.
Subject-specific optimization of background suppression for arterial spin labeling MRI using a real-time feedback loop on the scanner
Authors: Koolstra Kirsten , Staring Marius , Bruin Paul , van Osch Matthias
Published: August 2023

Background suppression (BGS) in arterial spin labeling (ASL) leads to perfusion images with a higher temporal signal-to-noise ratio (tSNR) compared to ASL without BGS. The optimal inversion times (TIs), and therefore the quality of the BGS, depend on the T1 relaxation times of the underlying tissue and on inhomogeneities of the scanner’s magnetic fields (B0, B1+). In this work, we designed and implemented a feedback mechanism that optimized the quality of background suppression in real time on the scanner. The results show an increased tSNR for the subject-specific optimization of BGS compared to standard BGS in 12 healthy volunteers.
The Knee Connectome: Studying Localized Synchrony in 8-year Cartilage Changes in Thickness and T2
Authors: Cummings Jennifer , Gao Kenneth , Chen Vincent , Martinez Alejandro Morales , Majumdar Sharmila , Pedoia Valentina
Published: August 2023

The trajectories of femur cartilage thickness and T2 relaxation time over an 8 year period were analyzed for 787 subjects from the Osteoarthritis Initiative dataset. Biomarkers were automatically extracted and used to generate time series for 27 regions of interest within the cartilage map to create a connectivity matrix (connectome). Statistically significant differences in thickness and T2 trajectories were found to correlate with demographic and clinical factors such as sex, BMI, Radiographic OA and presence of knee pain.
High Frame Rate Strain and Viscoelastic Analysis on Bovine Tibiofemoral Joints During Compression
Authors: Lee Woowon , Miller Emily , Luetkemeyer Callan , Neu Corey
Published: August 2023

Osteoarthritis (OA) is a degenerative process in cartilage mainly occurring in knee. OA affects the structure and function of cartilage thus, measuring the mechanical properties of cartilage is crucial. We use spiral DENSE MRI to quantify the mechanics of intact and defected bovine articular cartilage. The samples underwent cyclic compressive load and 27 frames are captured while the joint was compressed. Displacement and strain gradually increased over time and the defected cartilage showed higher strain in the tibiofemoral contact areas. We also found creep response in the defected cartilage which may be a potential biomarker for OA detection.
Cartilage T2 Relaxation Times are Related to Walking Asymmetries in Osteoarthritic Knees
Authors: Kruse Amelia , Carcia Austin , Bradshaw Adam , Ho Charles , Huard Johnny , Tashman Scott , Watkins Lauren
Published: August 2023

In this exploratory study, we examine relationships between joint function and cartilage composition in individuals with knee osteoarthritis (OA). MRI T2 relaxation times were used to assess articular cartilage and joint kinematics were recorded over walking gait cycles using video-motion analysis. There were significant correlations between cartilage T2 relaxation times and knee flexion, extension, and swing-stance ratio in both affected and contralateral legs. MRI measures of cartilage quality and joint function provide complimentary information that may be useful in measuring disease progression and intervention effectiveness using MRI.
Prospective motion correction for 2D T1-Mapping in the liver using an ultra-wideband radar system
Authors: Neumann Tom , Ludwig Juliane , Kerkering Kirsten , Speier Peter , Seifert Frank , Kolbitsch Christoph
Published: August 2023

We present a radar-based approach for prospective motion correction for 2D T1 mapping of the abdomen. An ultra-wideband radar signal is acquired simultaneously but otherwise completely independent of the MR measurement. This allows us to correct for in-plane as well as through-plane motion during MR acquisition. This is especially important for 2D T1 mapping, where motion can cause not only blurring and streaking artifacts, but also inaccurate values when unexcited volumes move through the recorded image plane. It is demonstrated that the method strongly improves T1 maps in phantom and in-vivo scans.
Energy dependent z-scores improve parallel imaging motion correction using trimmed autocalibrating k-space estimation (TAKE)
Authors: Beaumont Jeremy , Troalen Thomas , Nimje Swetali , Rapacchi Stanislas , de Rochefort Ludovic
Published: August 2023

MRI motion corruption prevents clinical interpretation and image analysis for research purposes. The trimmed autocalibrating k-space estimation based on parallel imaging and structured matrix completion (TAKE) algorithm was previously proposed to retrospectively correct motion corrupted raw k-space data. This study proposes specific modifications of the TAKE algorithm to decrease its computation time and improve the detection of motion-corrupted k-space data. The proposed changes significantly improve the TAKE motion detection sensitivity and specificity along with its motion correction performance, while sufficiently decreasing its computation time to allow for its use in a standard clinical routine workflow.
Spread-Spectrum Modulated Pilot Tone (SSMPT) for Motion Sensing
Authors: Abraham Daniel , Anand Suma , Lustig Michael
Published: August 2023

Pilot Tone (PT) navigators are tones within the MR receiver bandwidth that are used to estimate subject motion. However, the PT must be placed outside the imaging band. This is not always feasible for all types of imaging (e.g. spine imaging) and systems, since the PT may overlap with the image. In this work, we propose Spread-Spectrum Modulated Pilot Tone (SSMPT), which spreads the energy of the pilot tone over the entire imaging band. SSMPT produces comparable motion estimates to PT and respiratory bellows, as demonstrated in a free-breathing scan with a healthy volunteer.
Multi-shot DW-EPI using a modified interleaving scheme and second-order motion-compensated diffusion sensitization
Authors: Michael Eric , Hennel Franciszek , Pruessmann Klaas
Published: August 2023

Multi-shot techniques for diffusion MRI are desirable because of the associated improvement potential in image resolution but are inhibited by phase variability across interleaves, which results from subject motion and causes ghosting. Here, an EPI-based acquisition strategy is devised which diminishes the ghosting pattern by employing a modified interleaving scheme and mitigates motion sensitivity by nulling the first- and second-order moments of the diffusion-sensitizing gradient waveforms. This solution yielded unperturbed, high-resolution images in in vivo human brain scans and clear improvements in image quality compared to acquisitions incorporating standard interleaving and uncompensated diffusion sensitization.
The impact and correction of inter-scan motion artefacts in variable flip angle R1 mapping at 3T and 7T
Authors: Callaghan Martina , Aghaeifar Ali , Balbastre Yael , Corbin Nadège
Published: August 2023

Images acquired with variable nominal flip angle (VFA) can be combined with a map of the transmit field efficiency and a signal model to estimate the longitudinal relaxation rate, R1. However, if motion occurs between the acquisition of the VFA volumes the inherent assumptions of consistent receive field modulation and transmit field efficiency can be violated causing substantial errors in R1. Through in vivo experiment and simulation we show that the differential receive field modulation introduces the largest amount of error. We further show that the majority of the error can be mitigated with a simple, time efficient correction.
Multi-vendor comparison of three-dimensional multi-parametric mapping of the human brain at 3T: A multi-center study
Authors: Fujita Shohei , Gagoski Borjan , Hwang Ken-Pin , Warntjes Marcel , Hagiwara Akifumi , Fukunaga Issei , Uchida Wataru , Nishimura Yuma , Muroi Tomoya , Akatsu Toshiya , Kasahara Akihiro , Sato Ryo , Ueyama Tsuyoshi , Andica Christina , Kamagata Koji , Amemiya Shiori , Takao Hidemasa , Abe Osamu , Aoki Shigeki
Published: August 2023

Cross-vendor techniques enabling the pooling of data among different vendors is desired in multi-center projects; however, few mapping techniques have shown compatibility. In this study, we examined the intra-scanner repeatability and inter-vendor reproducibility of quantitative measurements obtained via a multi-parametric mapping technique, 3D-QALAS. Volunteers underwent scan-rescan sessions on four different 3T systems from three MRI vendors (GE, Philips, and Siemens). T1, T2, and PD values and brain tissue volumes of healthy volunteers derived from 3D-QALAS were robust across scanners from different vendors (inter-vendor coefficient of variation=3.3%). The data in this study will inform future technical developments for 3D-QALAS.
Genetically Engineered “Multicolour” MRI Reporters for In Vivo Imaging of Transgenes Expression
Authors: Allouche-Arnon Hyla , Khersonsky Olga , Tirukoti Nishanth , Avram Liat , Harris Talia , Yadav Nirbhay , Fleishman Sarel , Bar-Shir Amnon
Published: August 2023

Genetically engineered multicolor fluorescent proteins have changed biomedical research by enabling multiplexed mapping of transgenes expression. However, although MRI reporter genes have been developed, the ability to monitor multiple reporters that are expressed simultaneously and present them in a multicolor fashion is still needed. Here, we present an MRI-based system, comprising computationally designed reporters (enzymes) combined with MRI-detectable synthetic probes (substrates) for non-invasive color-encoded MRI mapping of transgene expression. Systemically administered reporter probes exclusively accumulate in cells expressing the designed reporter genes allowing their spatial display as pseudo-colored CEST MRI maps as demonstrated in both tumor model and viral-delivery system.
High resolution CINE imaging of guided knee motion using golden-angle radial MRI and a novel knee loading device
Authors: Aleksiev Martin , Krämer Martin , Brisson Nicholas , Maggioni Marta , Duda Georg , Reichenbach Jürgen
Published: August 2023

An MRI-safe device guiding knee motion/loading with a rotary encoder was used during MRI measurements of multiple knee flexion-extension cycles using radial gradient echo imaging with the golden-angle as a radial increment. Reproducibility of knee motion was investigated and anatomical CINE images were reconstructed for different knee angles by synchronizing the encoder data with the MRI data and selective gating, enabling evaluation of musculoskeletal conditions.
In-vivo 31P MRSI in healthy and malignant human pancreas at 7 Tesla
Authors: Seelen Leonard , van den Wildenberg Lieke , Gursan Ayhan , van der Velden Tijl , Gosselink Mark , Froeling Martijn , van der Kemp Wybe , Hoesein Firdaus Mohamed , Mohammad Nadia Haj , Molenaar I. , van Santvoort Hjalmar , Klomp Dennis , Prompers Jeanine
Published: August 2023

Early response assessment for patients with pancreatic cancer receiving chemotherapy is limited. Detection of alterations in 31P metabolite levels during treatment could change this perspective. However, to date 31P MRS has not yet been demonstrated in the human pancreas in vivo. Here we show in-vivo 31P MRSI data in the pancreas of healthy subjects, using a 31P whole-body transmit coil in combination with a 16-channel receive array at 7T, and show moderate to good test-retest reliability. In addition, we demonstrate the feasibility of performing 31P MRSI in a patient with pancreatic cancer before and after chemotherapy.
Low power free-breathing absolute B1+ mapping in the human body at 7T using magnetic resonance fingerprinting
Authors: Lutz Max , Aigner Christoph , Dietrich Sebastian , Flassbeck Sebastian , Gatefait Constance , Kolbitsch Christoph , Schmitter Sebastian
Published: August 2023

At 7T, power restrictions are a major limitation to accurately map the absolute transmit magnetic field (B1+) in the body. To overcome this, we investigate an absolute B1+ mapping method with low RF power using magnetic resonance fingerprinting (MRF). Measurements are done in a phantom at 3T and in-vivo in the liver at 7T. Resulting maps are compared to the actual flip angle (AFI) method. The obtained results show good agreement between the two methods, while the MRF approach seems to perform better in regions of low B1+ amplitude. Motion robustness introduced by a radial acquisition scheme enables free-breathing measurements.
Fast Subject-Specific Local SAR and B1+ Prediction for PTx at 7T using only an Initial Localizer Scan
Authors: Brink Wyger , Staring Marius , Remis Rob , Webb Andrew
Published: August 2023

This work presents a method for local SAR and B1+ prediction using only a 9 seconds long localizer as input. The total procedure can be executed in less than 30 seconds for a birdcage setup and less than 45 seconds for an eight-channel PTx configuration, enabling seamless integration into the MR workflow.
A 3T/7T multiparametric protocol to characterize amyotrophic lateral sclerosis cervical spinal cord: benefits of ultra-high field MR imaging?
Authors: Mchinda Samira , Dintrich Rémi , Le Troter Arnaud , Lauriane Pini , Attarian Shahram , Vershueren Annie , Callot Virginie
Published: August 2023

With comparable acquisition times between 3T and 7T, 7T quantitative protocol offers better resolution and many opportunities to study regional impairments, especially in anterior gray matter subregions.

This preliminary study focused on ALS and age-matched healthy controls scanned at both 3T and 7T.

With the current postprocessing, abnormalities were mostly detected on the lower part of the cord (GM atrophy, WM/GM T1 impairments).

Future work will focus on longitudinal evolution and refined analysis to evaluate the sensitivity for prognostication and to determine individual topological evolution.
Molecular MRI and PET Imaging Detect Biomarkers of Neuroinflammation in Contusion Injured Spinal Cord
Authors: Mu Chaoqi , Reed Jamie , Tantawy Mohammed , Wang Feng , Chen Li Min , Gore John
Published: August 2023

Spinal cord injury (SCI) severity/recovery are influenced by complex pathological mechanisms. We used CEST/NOE MR and TSPO PET imaging to evaluate longitudinal molecular changes associated with neuroinflammation in a lumbar contusion SCI rodent model. The NOE(-1.6 ppm) peak amplitude significantly decreased and the CEST(3.5 ppm) peak amplitude increased in SCI rats, 1-week post-injury. Similarly, we detected significant increase in the uptake of a TSPO-targeting PET radiotracer at the SCI epicenter. The CEST/NOE pools can be linked to neuroinflammatory activity associated with glutamate release. The results indicate that CEST/NOE MRI measurements provide complementary information to TSPO PET measurement in SCI.
Measuring Spinal Cord Blood Flow with Multi-delay pseudo Continuous Arterial Spinal Labeling (pCASL)
Authors: Shou Qinyang , Shao Xingfeng , Wang Danny
Published: August 2023

The purpose of this study was to measure the spinal cord blood flow using high-resolution multi-delay pCASL. An optimized background suppression scheme was applied to suppress the cerebrospinal fluid signal. In-vivo study was performed on 5 healthy subjects. The results show stable cervical spinal cord (C1-C3) blood flow values within the spinal cord ROI, supporting the potential for further development and evaluation studies on noninvasive MRI of spinal cord perfusion.
Evaluating the capabilities and challenges of layer-fMRI VASO at 3T
Authors: Huber Renzo , Kronbichler Lisa , Stirnberg Rüdiger , Vizioli Luca , Ehses Philipp , Stöcker Tony , Fernández-Cabello Sara , Poser Benedikt , Kronbichler Martin
Published: August 2023

Sub-millimeter functional imaging at ultra high field (UHF) strengths can capture cortical layer-specific functional information flow within and across brain systems. However, UHF scanners are only available to appr. 100 privileged imaging centers, globally. In this work, we implement, characterise and apply a CBV-sensitive VASO sequence setup for widely accessible 3T scanners. We find that the longer T2*, and shorter T1 relaxation times at 3T can account for some of the lower z-magnetization in the inversion-recovery VASO sequence compared to 7T and 9.4T. We conclude that layer-fMRI VASO is applicable without too much further ado at 3T.
Exploring Brain Connectivity in Ageing Using Explainable Deep Learning
Authors: van Asch Tamar , De Jong Nathan , Backes Walter , Köhler Sebastian , van Boxtel Martin , Schram Miranda , Jansen Jacobus
Published: August 2023

There is a growing need for the understanding of the process of ageing and the ability to predict who is at risk of neurodegenerative diseases and mortality. This study aims to develop and train a convolutional neural network on structural brain connectivity data to predict age. dMRI is used to map the structural connectivity of the brain. The dataset comprises 3494 subjects from The Maastricht Study, a cohort study of individuals aged between 40 and 77 years. Brain age prediction on the test set resulted in a Pearson’s correlation coefficient of 0.70 and a mean absolute error of 5.1 years.
Early Chemotherapeutic Response Evaluation In Ewing Sarcoma Using Diffusion Weighted MRI
Authors: Kayal Esha Baidya , Alampally Jayendra Tiru , Sharma Raju , Bakhshi Sameer , Mehndiratta Amit , Kumar Rakesh , SH Chandrashekhara , Jana Manisha , Bhalla Ashu Seith , Sharma Mehar , Mridha Asit , Vishnubhatla Sreenivas , Kandasamy Devasenathipathy
Published: August 2023

The objective of this prospective study was to assess the role of diffusion weighted MRI for early evaluation of chemotherapy response in patients with Ewing sarcoma with RECIST 1.1 criteria correlation. Absolute apparent diffusion coefficient (ADC), normalized ADC (nADC) and tumor diameter at baseline and after 1st cycle of chemotherapy were assessed for early detection of chemotherapy response in 16 patients. Results showed, baseline nADC and after 1st chemotherapy cycle, relative percentage change (Δ%) in nADC & tumor-size were significant and observed to be useful markers of early chemotherapeutic response (AUC=0.700, 0.750, 0.938) in Ewing sarcoma.
Detection of a new resonance in human calf muscle in vivo at 7.0T using the down-field MRS
Authors: Nanga Ravi Prakash Reddy , Elliott Mark , Wilson Neil , Swago Sophia , Witschey Walter , Reddy Ravinder
Published: August 2023

We have detected a resonance that was not reported previously, with a chemical shift of ~9.7ppm occurring in down-field MRS (DFMRS) from the human calf muscle in vivo. Based on phantom data, we speculate that the contribution to this broad peak might be from nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). This is for the first time that this peak is observed and reported from the down-field spectra. It seems to be very specific to calf muscle and has not been identified from the down-field spectra of human brain in vivo, suggesting that it is a feature of muscle metabolism.
Deep Learning Reconstruction-Enabled 2D and 3D MR Neurography
Authors: Tan Ek , Wen Yan , Wang Kang , Fiore Jake , Lebel R. , Kaushik Suryanarayanan , Fung Maggie , Sneag Darryl
Published: August 2023

Deep learning reconstruction (DLRecon) was applied to shorter acquisition 2D Dixon and 3D short-tau-inversion recovery (STIR) brachial plexus MR neurography (MRN) sequences and were compared both qualitatively and quantitatively to standard clinical sequences. DLRecon 2D and 3D images demonstrated similar quality to standard images. DLRecon may facilitate implementation of shorter MRN protocols, thereby helping streamline MRN’s incorporation into busy clinical practices and providing the option of acquiring additional imaging planes.