bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct measurement of luminal diffusivity in prostate: Prostate diffusion at an echo time of 400 ms.
Authors: Lemberskiy Gregory , Coelho Santiago , Bruno Mary , Fieremans Els , Novikov Dmitry
Published: August 2024

We showcase, for the first time, a direct/model-free measurement of luminal diffusivity in prostate, where ADC contrast no longer contains the cellular contribution, and only describes features of the glandular lumen, which prominently shrink with increasing Gleason score. We show that with a 4m30s protocol, the luminal volume fraction, cellular and luminal diffusivities can be obtained with high accuracy/precision at 1.5x1.5x3.0 mm3, suggesting that this approach can feasibly replace the current state-of-the-art, ~6 minute, prostate diffusion acquisition.
Investigating tissue microstructure of prostate cancer using Linear Multi-scale Modeling of diffusion MRI data
Authors: Wichtmann Barbara , Westhoff Niklas , Weis Cleo-Aron , Strecker Ralph , Feiweier Thorsten , Albert Steffen , Wolter Moritz , Zöllner Frank , Baeßler Bettina , Nummenmaa Aapo , Fan Qiuyun , Huang Susie , Attenberger Ulrike
Published: August 2024

Linear Multi-scale Modeling (LMM) is an advanced diffusion-weighted imaging(DWI) technique that uses multi-shell, multi-diffusion-time DWI data to estimate tissue microstructure parameters, including volume fractions of restricted and hindered water compartments over a range of length scales and orientation distribution information. Here,we apply the LMM framework to characterize prostate cancer(PCa) lesions and correlate our results with histology. Within the histopathologically proven cancerous lesions we observed a significantly increased fraction of restricted diffusion, particularly within the 2μm and 7μm sized water compartments. LMM may enable the development of distinct diffusion microstructural signatures of PCa to facilitate diagnosis of clinically significant PCa lesions.
FEXI MRI detects increased blood-brain barrier water permeability in response to mild lung infection
Authors: Ohene Yolanda , Harris Will , Powell Elizabeth , Wycech Nina , Lasič Samo , South Kieron , Coutts Graham , Sharp Andrew , Lawrence Catherine , Boutin Hervé , Parker Geoff , Parkes Laura , Dickie Ben
Published: August 2024

Non-disruption alterations to the blood-brain barrier (BBB) can be difficult to detect and therefore require highly sensitive tools for reliable measurement. Here, we apply a BBB filter exchange imaging (BBB-FEXI) technique to assess the rat brain in response to mild Streptococcus pneumoniae lung infection. We observe a significant 78 ± 39 % increase in BBB water permeability during infection. Higher water exchange measures were associated with higher levels of vascular inflammation, while BBB tight junction proteins remained unchanged. The expression of aquaporin-4 water channel was 38% higher in infected animals, which may drive the increase in water exchange during infection.
Investigating the applicability of dual echo ASL for simultaneous BOLD- and CBF-based mapping of cerebrovascular reactivity
Authors: Hoffmann Gabriel , Richter Franziska , Kufer Jan , Schmitzer Lena , Gleißner Carina , Göttler Jens , Kaczmarz Stephan , Preibisch Christine
Published: August 2024

Combined measurement of BOLD- and CBF-based CVR by means of deASL would be valuable for assessment of cerebrovascular diseases. To investigate the applicability of deASL for CVR mapping, we acquired GE-EPI, deASL and pCASL data from 21 healthy volunteers during a hypercapnia challenge. BOLD-CVR from deASL was slightly but significantly less sensitive to hypercapnia-induced BOLD signal changes than GE-EPI, while differences between deASL- and pCASL-based CBF-CVR were rather insignificant. However, deASL failed in 5 of 21 subjects, while pCASL and GE-EPI merely failed in two and one subjects, respectively. Thus, we expect an elevated deASL failure rate in patient populations.
Deep Reconstruction Framework with Self-calibration Mechanisms (DEISM) for Accelerated CEST Imaging
Authors: Xu Jianping , Zu Tao , Hsu Yi-Cheng , Sun Yi , Zhang Yi
Published: August 2024

The widespread clinical adoption of chemical exchange saturation transfer (CEST) imaging has been hampered by its prolonged scan time, due to multiple data acquisitions over the varying saturation offset frequencies. In this work, we utilize the artifact suppression algorithm and propose an effective deep reconstruction framework with self-calibration mechanisms (DEISM). The DEISM method was validated on brain tumor patients at 3T. In conjunction with deep-learning multi-coil image reconstruction and data-driven artifact suppression mechanisms, DEISM can provide reliable reconstructions of highly accelerated CEST data, yielding superior performance compared to state-of-the-art methods.
An end-to-end residual learning VarNet for under-sampled MRI reconstruction
Authors: Zhang Lijun , Wang Sha
Published: August 2024

Model driven deep learning reconstruction methods usually utilize residual learning within single cascade which is composed by a neural network and a data consistency module, here we propose a model based end-to-end residual learning variational network(E2E-ResVarNet), a k-space residual is passed through cascades, then added to acquired under-sampled k-space after the last cascade output. It was demonstrated that the image quality is significantly improved at 4x/6x/8x acceleration factors trained with brain data set.
Cross-vendor three-dimensional multiparametric mapping of the human brain: A traveling-subject and patient study
Authors: Fujita Shohei , Gagoski Borjan , Hwang Ken-Pin , Warntjes Marcel , Yokoyama Kazumasa , Fukunaga Issei , Uchida Wataru , Saito Yuya , Tachibana Rina , Muroi Tomoya , Akatsu Toshiya , Kasahara Akihiro , Sato Ryo , Ueyama Tsuyoshi , Andica Christina , Hagiwara Akifumi , Kamagata Koji , Amemiya Shiori , Takao Hidemasa , Hattori Nobutaka , Abe Osamu , Aoki Shigeki
Published: August 2024

Multiparametric techniques compatible with multiple vendors to facilitate the pooling of data among different sites and vendors are desired. Here, we developed a vendor-standardized whole-brain multiparametric mapping scheme based on 3D-QALAS. Intra-scanner repeatability and inter-vendor reproducibility were evaluated on test-retest session data on five different 3T systems from four MRI vendors (GE, Philips, Siemens, and Canon). T1 and T2 relaxation times and proton density values derived from 3D-QALAS showed coefficient of variations of <4.0% across scanners from different vendors. Finally, we performed an inter-vendor validation on multiple sclerosis patients to assess the feasibility of the scheme in real-world clinical settings.
Brain Stiffness, Aerobic Fitness, and Memory Performance Differences Between Older Adults with and without Mild Cognitive Impairment
Authors: Kramer Mary , Delgorio Peyton , Diano Alexa , Bailey Olivia , McIlvain Grace , Twohy Kyra , Overstreet Matthew , Edwards David , Martens Christopher , Johnson Curtis
Published: August 2024

Magnetic resonance elastography (MRE) is a robust and sensitive tool used to measure brain mechanical properties that can accurately detect improvements in brain health and function. Exercise and aerobic fitness levels are strongly tied to these brain mechanical properties and their related functionality. In healthy older adults, greater fitness is associated with better memory and increased mechanical integrity of the brain. In a population of older adults with mild cognitive impairment, there is a notable decrease in memory function and aerobic fitness compared to healthy controls, and this decrease is measurable in the mechanical properties of the brain using MRE.
Increased vessel size accompanies decreased cerebral blood flow in the hippocampus in Alzheimer’s disease
Authors: Lee Hansol , Gaudet Kyla , Bryant Annie , Bennett Rachel , Salat David , Yen Yi-Fen , Huang Susie
Published: August 2024

The purpose of this study was to probe alterations in vessel size and their contributions to perfusion deficits observed in the early stages of Alzheimer’s disease (AD). AD and mild cognitive impairment (MCI) patients along with older and young adults underwent perfusion and diffusion magnetic resonance imaging (MRI). Increased vessel size was observed in conjunction with decreased cerebral blood flow in the hippocampus of individuals with AD and MCI. These results highlight potential pathologic mechanisms of abnormal vascular supply to the hippocampus in AD. Further investigations into vessel density and the relationship between cerebrovascular structure to AD pathology are warranted.
Cortical morphometry and hippocampal microstructure predict aging and Alzheimer’s disease progression.
Authors: Bussy Aurélie , Patel Raihaan , Parent Olivier , Salaciak Alyssa , Farzin Sarah , Tullo Stephanie , Villeneuve Sylvia , Poirier Judes , Breitner John , Devenyi Gabriel , Tardif Christine , Chakravarty M. Mallar
Published: August 2024

Morphometric and quantitative MRI metrics have rarely been used simultaneously to characterize healthy aging and Alzheimer’s disease (AD) progression. Here, cortical vertex-wise and hippocampal voxel-wise metrics were extracted to infer atrophy progression (using cortical thickness, surface area or relative Jacobians), myelin and iron contents (T1 and T2* respectively). A data-driven approach was used to parcellate the cortex and the hippocampus. A multivariate statistical technique was used to link hippocampal and cortical metrics to demographics and cognitive scores of interest. Our results suggest that AD-related neural risk is associated with neurodegeneration and microstructural changes in the cortex and hippocampus, respectively.
Only-Train-Once MR Fingerprinting for B0 and B1 Inhomogeneity Correction in Quantitative Magnetization Transfer Contrast
Authors: Kang Beomgu , Singh Munendra , Park HyunWook , Heo Hye-Young
Published: August 2024

Magnetization transfer contrast MR fingerprinting (MTC-MRF) enables fast reconstruction of free bulk water and semisolid macromolecules parameters. However, B0 and B1 inhomogeneities that originate from system imperfection can corrupt MR fingerprints, thereby impairing the tissue quantification. We proposed a fast, deep-learning MTC-MRF technique that simultaneously estimates multiple tissue parameters and corrects the effect of B0 and B1 variations. An only-train-once recurrent neural network was designed to perform the fast tissue parameter quantification regardless of MRF acquisition schedule. This allows a dynamic scan-wise linear calibration of the scan parameters using the measured B0 and B1 maps.
Optimizing an Accelerated Spin- and Gradient-Echo Sequence for Dynamic MR Vascular Fingerprinting
Authors: Wheeler Gregory , Le Linh , Lee Quimby , Fan Audrey
Published: August 2024

An accelerated spin- and gradient-echo (SAGE) pulse sequence sensitive to changes in oxygenation has been demonstrated to be suitable for MR vascular fingerprinting (MRvF), potentially enabling quantitative, multiparametric mapping of dynamic vascular physiology. This study aimed to optimize this SAGE sequence and matching algorithms used in MRvF and found that selecting shorter echo times resulted in better signal properties and sensitivity for pattern matching with lower estimation error. This optimization will enable these techniques to be used during dynamic vascular challenges and investigations into multiple, simultaneous functional cerebrovascular biomarkers.
MRF-derived T1 and T2 map alterations in four different brain atrophy patterns in a cohort of MCI subjects
Authors: Bosco Paolo , Biagi Laura , Cencini Matteo , Lancione Marta , Matteoli Michela , Cintoli Simona , Sale Alessandro , Berardi Nicoletta , Tosetti Michela , Consortium the Train the Brain
Published: August 2024

Brain atrophy evaluation is crucial in the assessment of neurodegenerative diseases. However, the most common MRI measures (mostly T1-weighted derived) cannot be considered as quantitative. In this study we use T1-weighted images to identify homogeneous groups of MCI subjects in terms of brain atrophy and we assessed the capability of T1 and T2 quantification through MRF technique to elucidate at voxel level the brain alterations with respect to an age-matched healthy population. Indeed, atrophy patterns can be identified in both T1 and T2 maps paving the way to innovative brain atrophy assessment in a quantitative fashion.
APT weighted imaging combined with IVIM to evaluate Her-2 gene expression in endometrial cancer
Authors: Changjun Ma , Shifeng Tian , Qingling Song , Lihua Chen , Nan Wang , Liangjie Lin , Jiazheng Wang , Ailian Liu
Published: August 2024

it is necessary to find a method for non-invasive monitoring of Her-2 status. MRI with characteristics of multi-direction, multi-parameter, multi-function, high soft-tissue resolution, and non-invasiveness, has become the preferred method for evaluation of uterine lesions.
Microcirculatory changes in the uterus of women during the menstrual cycle - based on intravoxel incoherent motion MRI
Authors: Li Yajie , Zhang Qi , Fu Caixia , Li Qing , Grimm Robert
Published: August 2024

Purpose: To assess the feasibility of intravoxel incoherent motion MRI on detecting the microcirculatory changes in the uterus of women during the menstrual cycle. Methods: Volunteers underwent MRI scans by using IVIM. The changes of D value, D* and f value of three layers of uterine structure during menstrual cycle were analyzed quantitatively. Results: During menstrual cycle, the D values of junctional zone were significantly lower than in myometrium. Meanwhile, the f values of the three zones structure of uterus were significantly different. Conclusion: IVIM can be used for noninvasive and quantitative evaluation of uterine blood microcirculation changes.
White matter changes detected based on multi-component MR Fingerprinting in Multiple Sclerosis
Authors: Nagtegaal Martijn , Hermann Ingo , Weingärtner Sebastian , Martines-Heras Eloy , Solano Elisabet , Llufriu Sare , Gass Achim , Poot Dirk , van Osch Matthias , Vos Frans , de Bresser Jeroen
Published: August 2024

White matter hyperintensities are an MRI biomarker of Multiple Sclerosis (MS). However, not all white matter changes are visible on conventional, qualitative MRI. We applied a multi-component MR Fingerprinting protocol to identify potential white matter abnormalities based on increased $$$T_2^*$$$-values. FLAIR and MRF scans were performed in 44 MS patients and 12 healthy control subjects. Significant differences were found in the volume of MRF components with 500ms<$$$T_1, T_2^*$$$<2.5s. This volume correlated moderately with white matter damage on structural MR images. The MRF approach identified larger abnormal tissue volumes than those visible on the structural scans.
Accelerated 3D MR cholangiopancreatography using a deep learning-based reconstruction in patients with cholelithiasis
Authors: Zhang Yu , Xia Chunchao , Li Zhenlin , Zhang Xiaoyong
Published: August 2024

In this work, we aimed to compare image quality and lesion detectability in patients suspected with gallstones among single breath-hold three-dimensional magnetic resonance cholangiopancreatography (MRCP) with gradient and spin-echo (GRASE) technique, with compressed sensing (CS) and with deep learning (DL) technique. DL MRCP showed the best image quality and better lesion conspicuity and lesion edge sharpness.
Pseudo Partition-encoded Simultaneous Multislab (pPRISM) for Submillimeter Diffusion Imaging Without Navigator and Slab-Boundary Artifacts
Authors: Chang Wei-Tang
Published: August 2024

The ability to achieve submillimter isotropic resolution diffusion MR imaging (dMRI) is critically important to study fine-scale brain structures. While the multi-shot approaches, including SMSlab and gSlider-SMS, have been proposed to mitigate the inherently low SNR, the SMSlab sequences require additional navigators for phase estimation and both SMSlab and gSlider-SMS suffered from the slab-boundary artifacts. This study proposed two new concepts: PRISM encoding and 2) pseudo slab in order to mitigate the slab-boundary artifacts and shorten the scan time. Together, this study achieved the dMRI with 0.86 mm isotropic resolution with 16.3%-43.6% reduction of scan time compared to gSlider.
Benchmarking common and advanced non-Cartesian trajectories with high acceleration and static off-resonance effects
Authors: Daval-Frérot Guillaume , R Chaithya G , Ponce Fernanda , Massire Aurélien , Mailhe Boris , Nadar Mariappan , Vignaud Alexandre , Ciuciu Philippe
Published: August 2024

Non-Cartesian sampling patterns allow for highly accelerated MRI exams at the cost of exacerbated and more complex artifacts, each impacting image quality in unique ways. Patient-induced B0 field inhomogeneities can notably cause distortions and blurring, but some trajectories are by design more robust to them. We propose to retrospectively benchmark 16 different non-Cartesian sampling patterns with high acceleration factor (AF=20) and realistic off-resonance artifacts over 9 volumes acquired at 3T with 0.6 mm isotropic spatial resolution. SPARKLING and spiral-based trajectories achieve higher image quality scores, but only the former shows robustness to off-resonance effects through the MORE-SPARKLING extension.
Alterations in intrinsic functional networks in squirrel monkey spinal cord after focal damage to primary motor cortex using resting state fMRI
Authors: Sengupta Anirban , Yang Pai-Feng , Reed Jamie , Mishra Arabinda , Wang Feng , Chen Li Min , Gore John
Published: August 2024

The goal of this study was to detect and quantify how functional connectivity within networks in squirrel monkey spinal cord changes after a focal lesion of the primary motor cortex. We first used independent component analysis to identify 7 spatially independent functional hubs within each segment of the cervical spinal cord. The overall connectivity of these spinal cord networks increased after a lesion within M1, indicating plastic changes in spinal cord due to cortical injury. Distinct functional communities confined to neighboring spinal cord segments were identifiable one week after the injury, confirming spinal cord functional networks reorganized over that time.
A longitudinal study of cerebral metabolite alteration in the developmental monkey brain with Huntington's disease
Authors: Li Chunxia , Zhang Xiaodong
Published: August 2024

Previous studies have demonstrated in vivo MRS could be an effective approach to assess the metabolite changes in Huntington Disease (HD) patients and models. However, its sensitivity to detect the metabolite abnormality is still in dispute. The metabolic changes in the striatum of transgenic monkeys of HD were investigated with MRS from 12 to 60 months of age here. A progressive and significant reduction of NAA/tCr and NAA/tCho in striatum was observed at 30 and 36 months and old, respectively, suggesting the sensitivity of the in vivo MRS to assess the neurochemical alteration in the evolution of the disease.
A Method for Detection of Subtle Blood-Brain Barrier Disruption using Non-Contrast MR Fingerprinting
Authors: Thomson Emma , Powell Elizabeth , Wheeler-Kingshott Claudia Gandini , Parker Geoff
Published: August 2024

Using magnetic resonance fingerprinting (MRF), we propose a method for regional quantification of blood volume (νb) and BBB water exchange (by quantifying capillary water residence time, τb), as a metric of BBB function/dysfunction. A single axial slice was acquired for seven healthy volunteers using an MRF SPGR sequence. Matching to a precomputed dictionary was performed to simultaneously quantify intra and extravascular T1, B1+, νb, and τb. Initial findings in volunteers show that it is possible to quantify these five parameters simultaneously. Our results show promise for patient studies of blood-brain barrier disruption.
ASL spatial coefficient of variance predicts increased white matter hyperintensities volume over time in cognitively unimpaired subjects
Authors: Padrela Beatriz , Collij Lyduine , Lorenzini Luigi , Ingala Silvia , Sudre Carole , Visser Pieter Jelle , Braber Anouk den , Barkhof Frederik , Petr Jan , Mutsaerts Henk
Published: August 2024

Arterial transit artifacts (ATAs) in arterial spin labeling (ASL) images are common in populations with prolonged arterial transit time (ATT) and may be associated with vascular insufficiency. The spatial coefficient of variance (sCoV) of ASL images can quantify the presence of these artifacts. Vascular insufficiency could contribute to the development of white matter hyperintensities (WMH), a common marker of cerebral small vessel disease. We demonstrated that baseline sCoV of CBF is associated with WMH at baseline and predicts WMH volume change, in a cognitively unimpaired population of 88 subjects.
Optimized signal saturation for fast functional line-scanning of cortical layers
Authors: Nothnagel Nils , Morgan Tyler , Symon Alison , Muckli Lars , Goense Jozien
Published: August 2024

Layer-dependent fMRI is typically performed at sampling rates below 1 Hz and voxel sizes of 0.7-0.9 mm3 containing signal from multiple anatomical layers. Line-scanning can enhance spatial resolution to 0.2-0.4 mm while maintaining sub-second TR. It is therefore an ideal method to study temporal evolution of BOLD responses across cortical layers. However, current saturation schemes for human line-scanning suffer from broad saturation profiles that lead to signal contamination of BOLD responses from adjacent areas. We implemented line-scanning in humans with sharp line-profiles of 3 mm. Using this method, we show that cortical layers of M1 have unique BOLD time courses.
Layer-specific functional connectivity with 3D VAPER fMRI
Authors: Chai Yuhui , Morgan A. , Xie Hua , Li Linqing , Huber Laurentius , Bandettini Peter , Sutton Bradley
Published: August 2024

We introduced a whole-brain 3D VAPER sequence tool and analysis approach for layer-specific resting state fMRI. It allows investigation of the directional connectivity between brain areas and determine whether any given connection is better described as predominantly feedforward vs. feedback driven. To exemplify this, we demonstrated that different directions of the same connection within the default mode network (mPFC <-> PCC/Parietal region) lead to different laminar correlation profile, suggesting different projection types (feedforward/feedback).
Local $$$B_1^+$$$ shimming improves visualization of the bone-metal interface in patients with orthopedic hardware
Authors: Khodarahmi Iman , Keerthivasan Mahesh , Fritz Jan
Published: August 2024

$$$B_1^+$$$ field inhomogeneity is a source of metal artifacts in patients with orthopedic hardware. Local $$$B_1^+$$$ shimming can potentially decrease these artifacts and improve visualization of the bone-metal interface. Our proposed turbo-spin echo-based $$$B_1^+$$$ mapping technique enables accurate estimation of the $$$B_1^+$$$ field near the metal hardware. After optimization for in-vivo applications, the technique was successfully employed on a clinical 3.0 T parallel-transmit system aiming at $$$B_1^+$$$ shimming near the orthopedic hardware. Our results demonstrate significant improvement in visualization of the bone-metal interface compared to standard 1.5 and 3.0 T acquisitions.
Astrocyte dysfunction drives abnormal resting-state functional connectivity in depression
Authors: Liu Jiaming , Mo Jia-Wen , Wang Xunda , An Ziqi , Zhang Shuangyang , Zhang Can-Yuan , Yi Peiwei , Leong Alex , Ren Jing , Chen Liang-Yu , Mo Ran , Xie Yuanyao , Feng Qianjin , Chen Wufan , Gao Tian-Ming , Wu Ed X. , Feng Yanqiu , Cao Xiong
Published: August 2024

Even though brain-wide network-level abnormalities in major depressive disorder (MDD) patients via resting-state functional MRI (rsfMRI) exist, the mechanisms underlying such network changes are unknown. Here, we show that the astrocytic calcium deficient mice, inositol 1,4,5-trisphosphate-type-2 receptor knockout mice (Itpr2-/- mice), display abnormal rsfMRI connectivity (rsFC), which is highly consistent with those of MDD patients. Optogenetic activation of medial prefrontal cortex (mPFC) astrocytes partially rescues rsFC. Optogenetic activation of the mPFC neurons or mPFC-striatum pathway rescues disrupted rsFC and depressive-like behaviors in Itpr2-/- mice. Our results identify the previously unknown role of astrocyte dysfunction in driving rsFC abnormalities in depression.
Quantitative MRI biomarkers of pathology in a Poly I:C rat lactational model of schizophrenia and depression
Authors: Helft Coral , Katzir Tamar , Omer Noam , Shamir Emilya Natali , Piontkewitz Yeal , Weiner Ina , Shahar Shimon , Ben-Eliezer Noam
Published: August 2024

Many psychiatric conditions lack radiologic markers of disease. In this study, we investigated the utility of quantitative MRI (qMRI) for detecting pathology in the lactational immune activation rat model of schizophrenia and depression. Results show that a logistic regression model can identify the disease with an accuracy of 81% based on a combination of T1 and T2, mean diffusivity, and fractional anisotropy values. This finding suggests that multiparametric qMRI is useful for monitoring pathology with an objective quantitative tool that goes beyond structural deformations and improves the sensitivity to microstructural and neurochemical pathology in the lactational immune activation rat model.
Exchange between structurally-disordered compartments
Authors: Novikov Dmitry , Coronado-Leija Ricardo , Fieremans Els
Published: August 2024

Which signatures of the diffusion signal are responsible for non-Gaussian diffusion inside cells or extra-cellular space, and which ones are the hallmark of the exchange between compartments? Answering this unresolved question is vital for mapping tissue microstructure in brain (especially in gray matter) and body. Here we employ the effective medium formalism to extend the multi-site exchange approach onto the case when diffusion in each tissue compartment is arbitrarily complex. We find the time-dependent diffusivity and kurtosis of a general system of exchanging non-Gaussian compartments for all times, validate with Monte Carlo simulations, and discuss practical implications.
Machine learning-based prediction of stroke outcome in mice from MRI and behavioral testing
Authors: Boehm-Sturm Philipp , Knab Felix , Koch Stefan , Major Sebastian , Farr Tracy , Mueller Susanne , Euskirchen Philipp , Eggers Moritz , Kuffner Melanie , Walter Josefine , Dreier Jens , Endres Matthias , Dirnagl Ulrich , Wenger Nikolaus , Hoffmann Christian , Harms Christoph
Published: August 2024

Prediction of motor-functional outcome in mice could potentially guide researchers in their treatment decisions in preclinical stroke intervention studies and support outcome-dependent stratifications. We pooled 13 studies in which mice underwent identical MRI and behavioral testing protocols. In this large cohort of mice (n=148), we developed and compared machine learning-based predictors of post-stroke recovery.
Stereotactic MR-guided Adaptive Radiotherapy for Pancreatic Cancers on a 1.5 Tesla MR-linac system
Authors: Lee Danny , Oh Seungjong , Hwang Min-Sig , Pavord Daniel , Sohn Jason , Colonias Athanasios , Trombetta Mark , Kirichenko Alexander , Renz Paul
Published: August 2024

Ablative SBRT to pancreatic cancers on MRI-Linac is a novel and rapidly evolving technology allowing real-time visualization of tumor and nearby organs-at-risk (OAR). Reliable identification of pancreas tumors on MR-Linac has direct impact on radiotherapy planning and outcome. A novel workflow was clinically implemented for pancreas stereotactic body radiotherapy on Elekta Unity MR-Linac. Compared to T2W images, pancreas tumors on T1W images, were superiorly visible for accurate delineation during the entire treatment course. This study is the first to determine the impact of an optimized MR sequence for pancreas tumors and OARs during multi-fractionate MR-guided radiotherapy on 1.5T Elekta MR-Linac.
Multi-parametric ageing study on 51 subjects in the lower leg by 1H water T1 MR fingerprinting, multi-compartment water T2, fat fraction and 31P MRS
Authors: Kolkovsky Alfredo Lopez , Matot Béatrice , Reyngoudt Harmen , Marty Benjamin , de Almeida Araujo Ericky Caldas , Fromes Yves
Published: August 2024

Aging is a multi-factorial process and studies in the lower leg are scarce. We performed a multi-contrast protocol in 51 volunteers from 20 to 81 y.o. We found an age-related increase of muscle water T1(water-fat separation,MR fingerprinting), fat fraction, water T2 and T2 heterogeneity in the anterior and posterior compartments. Phosphodiesters and mitochondrial stress biomarkers also increased with age. Through bi-compartment water T2 CPMG measures, age-related increases of the long water T2 relative fraction were observed relative to the short water T2 (T2-H2O-CPMG-short) fraction, but T2-H2O-CPMG-short values were unaltered with age, suggesting inflammation with preservation of the intracellular water compartment.
Interleaved BOLD and 31P-MRS examination of working human upper arm muscles
Authors: Hooijmans Melissa , Jeneson Jeroen , van der Berg Sandra , Strijkers Gustav , Nederveen Aart
Published: August 2024

Phosphorous (31P) MRS is frequently used to study alterations in muscle mitochondrial function but works under the assumption that exercise triggers sufficient changes in perfusion to allow for delivery oxygen and energy substrates to the tissue. Here, we used interleaved scanning of 31PMRS and BOLD imaging to obtain an in-debt evaluation of muscle oxidative capacity in the upper arm muscles during arm-cycling exercise. We demonstrated that similar levels of PCr depletion and PCr recovery times resulted in variable Time-To-Peaks (TTPs) and max %BOLD response while a tendency was observed between a lower end-exercise pH and longer TTP.
Magnetic resonance fingerprinting for objective and contrast-free focal liver lesion characterization: A preliminary study
Authors: Sano Katsuhiro , Fujita Shohei , Cruz Gastao , Velasco Carlos , Kawasaki Hideo , Fukumura Yuki , Suzuki Akiyoshi , Morita Yuichi , Kamagata Koji , Fukunaga Issei , Yoneyama Masami , Kuwatsuru Ryohei , Saiura Akio , Ikejima Kenichi , Botnar Rene , Prieto Claudia , Aoki Shigeki
Published: August 2024

Objective and contrast-free methods for differentiating benign focal liver lesions from malignant lesions (e.g., hepatocellular carcinomas and metastases) are desired. Herein, we evaluated the diagnostic capability of liver magnetic resonance fingerprinting (MRF) in patients with focal liver lesions. Liver MRF provided repeatable T1, T2, T2*, and fat-fraction values for various focal liver lesions. The liver MRF T1 and T2 relaxation times showed high agreement with separate conventional quantitative mapping measurements. Measurements of liver MRF and a combination of MRF relaxation times provided good differentiation of focal liver lesions (AUC of 0.87 for differentiating common benign lesions from common malignant lesions).
Monotone Operator Learning: a robust and memory-efficient physics-guided deep learning framework
Authors: Pramanik Aniket , Jacob Mathews
Published: August 2024

MRI has been revolutionized by compressed sensing algorithms, which offer guaranteed uniqueness, convergence, and stability. In the recent years, model-based deep learning methods have been emerging as more powerful alternatives for image recovery. The main focus of this paper is to introduce a model based algorithm with similar theoretical guarantees as CS methods. The proposed deep equilibrium formulation is significantly more memory-efficient than unrolled methods, which allows us to apply it to 3D or 2D+time problems that current unrolled algorithms cannot handle. Our results also show that the approach is more robust to input perturbations than current unrolled methods.
Multi-echo MRI Reconstruction with Iteratively Refined Zero-shot Spatio-Temporal Deep Generative Prior
Authors: Kim Tae Hyung , Cho Jaejin , Gagoski Borjan , Dong Zijing , Wang Fuyixue , Kang So Hyun , Bilgic Berkin
Published: August 2024

The subspace method has been widely used for multi-echo/contrast MRI reconstruction, assuming the temporal MR signal evolution can be compactly represented using a few linear coefficients. Recently, methods based on artificial neural networks (trained with large datasets) enabled nonlinear representations of temporal or spatio-temporal MR signals and demonstrated improved performance. This work proposes a novel zero-shot spatio-temporal generative prior for multi-echo/contrast MRI reconstruction, assuming the spatio-temporal MR signals can be nonlinearly generated using deep generative neural networks without external training data. The proposed method was evaluated with 3D-QALAS and EPTI data, and exhibited substantial improvement in NRMSE against existing methods.
Quantifying Cardiogenic Oscillations of Hyperpolarized 129Xe Gas Exchange MR Spectra in a Healthy Reference Cohort
Authors: Costelle Anna , Lu Junlan , Bechtel Aryil , Bier Elianna , Kabir Sakib , Mammarrappallil Joseph , Dai Haoran , Mummy David , Driehuys Bastiaan
Published: August 2024

Hyperpolarized 129Xe gas exchange MR spectra exhibit cardiogenic oscillations that have been found to distinguish between groups of cardiopulmonary diseases. Specifically, oscillations in the amplitude of the 129Xe red blood cell (RBC) resonance can differentiate pre-capillary and post-capillary pulmonary hypertension. Before diagnostic relevance can be established, these oscillations must be robustly quantified and definitive reference values must be determined. Here, we compare oscillation quantification using a constrained peak-finding algorithm against results from conventional sine fitting. We then employ a well-curated healthy cohort to establish reference values for cardiogenic oscillations in 129Xe RBC spectral parameters, using both methods.
Improving bSSFP-based quantitative magnetization transfer imaging with MR physics-informed artificial neural network
Authors: Luu Huan Minh , Park Sung-Hong
Published: August 2024

Most quantitative magnetization transfer imaging (qMT) protocols require additional T1 mapping scan. A recent on-resonance multiple phase-cycle bSSFP method was proposed for qMT that obviates the necessity for T1 mapping, but the fitting results were suboptimal. In this study, we proposed a physics-informed artificial neural network (ANN) to improve the fitting of this method. By using the MR signal model to generate the training data and regularize the network, no in-vivo data acquisition was necessary. Experiments on digital phantom and in-vivo data demonstrated improvement over previous method and better resilience against measurement noise.
Fast Diffusion fMRI (dfMRI) along the visual pathway closely tracks electrophysiological signals in the negative BOLD regime
Authors: Gil Rita , Valente Ana Mafalda , Shemesh Noam
Published: August 2024

The underlying sources of negative BOLD responses (NBRs) are still debated. We have recently shown that Positive BOLD response (PBR) to NBR transitions can be induced in the visual pathway by modulating the visual frequency of stimulation, reflecting neural activation/suppression, respectively. Here, we investigate how diffusion functional MRI (dfMRI) signals, which suffer less from vessel contamination, correspond to these activation and suppression regimes. Our results show that dfMRI signals are sharper and more sensitive to suppression induced at high visual stimulation frequencies. Furthermore, striking electrophysiology characteristics such as onsets and offset peaks are more prominent in the dfMRI signals.
Impact of image resolution on brain stiffness estimation using neural network inversion
Authors: Trevathan Jonathan , Scott Jonathan , Trzasko Joshua , Manduca Armando , Huston John , Ehman Richard , Murphy Matthew
Published: August 2024

To improve the clinical value of brain stiffness measurements, increased resolution is desired to accurately map the mechanical signatures of disease processes. However, MR elastography-based stiffness maps must be estimated by inverting the measured displacement fields. It is not well-established that increased acquisition resolution will directly translate to improved accuracy in the final mechanical property maps. In this simulation study, using two neural network inversions, we show 2-mm data outperforms 3-mm data for stiffness accuracy and precision across a range of signal-to-noise ratios.
Deep learning reconstruction of radial T2 weighted data sets with data consistent unrolled neural networks
Authors: Toner Brian , Arberet Simon , Han Fei , Nadar Mariappan , Deshpande Vibhas , Martin Diego , Altbach Maria , Bilgin Ali
Published: August 2024

Unrolled networks with data consistency layers have been shown to be effective in reconstructing MRI data. Radial turbo spin echo sequences enable acquisition of multi-contrast k-space data, which can be used to generate multi-contrast images at different echo times together with a co-registered T2 map. In this work, we will show that the cascading unrolled network architecture is effective in reconstructing images from radial turbo spin echo data. In order to do this, data consistency layers must be implemented to be able to combine data from multi-coil acquisitions and from multiple echo times.
Refining synthetic training data improves image quality transfer for ultra-low-field structural brain MRI
Authors: Ronan Lisa , Deoni Sean , Bruchhage Muriel , Ogbole Godwin , Figini Matteo , Lagunju Ikeoluwa , D'Arco Felice , Cross Helen , Fernandez-Reyes Delmiro , Cole James , Alexander Daniel
Published: August 2024

Computer vision methods can be used for image quality transfer (IQT) to address the poor contrast, decreased resolution and increased noise observed in MR images acquired at ultra-low magnetic fields. Current methods have been shown to produce high-quality synthetic outputs for low-field (~0.5T) but not ultra-low-field (~0.05T) field images. Moreover, these methods do not adapt well to the presence of abnormal morphology (e.g. lesions). Here we introduce a new approach to ultra-low field IQT that improves on previous methods and is adaptive to the presence of synthetic lesions.
Towards contact-free motion sensing technique at low-field MRI using beat pilot tone
Authors: Chen Suen , Sun Haoyu , Chen Hao , Anand Suma , Lustig Michael , Zhang Zhiyong
Published: August 2024

To improve the image quality in low field, the conventional method is to repeat scanning many times, and finally increase the SNR by averaging multiple imaging data. Unfortunately, long scan time can make images highly susceptible to motion artifacts. A recent contact-free motion detection technology Beat Pilot Tone (BPT) improves the sensitivity compared with Pilot Tone (PT) and is not limited by Larmor frequency. We introduce BPT in a 0.25T low-field MRI system, and successfully reduce the motion artifacts while improving SNR by binning the continuously acquired data into different motion states in image domain and k-space via BPT signal.
A Multi-Subject Deconvolution Algorithm for the Analysis of Naturalistic fMRI data
Authors: Uruñuela Eneko , Sava-Segal Clara , Leung Megan , Finn Emily , Caballero-Gaudes César
Published: August 2024

Collecting fMRI data during naturalistic paradigms has drawn considerable attention in human neuroscience as a way to investigate brain function in ecologically valid conditions. We introduce a novel method (multi-subject paradigm free mapping) to decipher BOLD events in a temporally agnostic manner, and explore concordant group activations and individual idiosyncrasies. Besides, it can operate at the fastest temporal and spatial resolutions of the data. We validate it on simulated and real naturalistic fMRI data, revealing events that track expected features of the stimulus. Overall, this technique substantially increases sensitivity in linking moment-to-moment brain activity to its underlying cause(s).
Electrophysiological correlates of BOLD events with high cofluctuation amplitude in the resting human brain
Authors: Figueiredo Patricia , Esteves Inês , Fouto Ana , Ruiz-Tagle Amparo , Caetano Gina , Caballero-Gaudes César
Published: August 2024

fMRI studies have shown that the large-scale organization of resting-state functional brain networks can be largely explained by a small fraction of events exhibiting high cofluctuation amplitude. However, their neurobiological relevance remains unclear. We investigated the electrophysiological origins of high cofluctuation amplitude BOLD events using concurrent EEG-fMRI data acquired from humans. We found that high amplitude cofluctuations were associated with higher delta power and lower alpha power. This association was specifically observed when considering delays ~6s between EEG and BOLD signals, supporting its neurovascular origin and suggesting that high cofluctuation BOLD events have a neurophysiological origin.
Imaging of Irradiation Effects in Brain Tissues by Electrical Conductivity Using MRI
Authors: Katoch Nitish , Choi Bup Kyung , Park Ji Ae , Kim Tae Hoon , Hur Young Hoe , Kim Jin Woong , Kim Hyung Joong
Published: August 2024

Radiation-induced injury can damage normal tissues caused by unintentional exposure to ionizing radiation. Image-based evaluation of tissue damage by irradiation has an advantage for the early assessment of therapeutic effects. This study aims to non-invasively evaluate tissue response following radiation therapy in phantoms and in vivo mouse brains at 3T and 9.4T MRI scanner. Due to changes in ionic strength in tissue after radiation, magnetic resonance (MR)-based electrical properties tomography could be a suitable imaging tool to assess the radiation therapy response on biological tissues.
128-channel brain imaging array with improved acceleration at 10.5 Tesla
Authors: Lagore Russell , Grant Andrea , DelaBarre Lance , Auerbach Edward , Waks Matt , Jungst Steve , Moeller Steen , Radder Jerahmie , Sadeghi-Tarakameh Alireza , Eryaman Yigitcan , Van de Moortele Pierre-Francois , Adriany Gregor , Ugurbil Kamil
Published: August 2024

Described is a 128-channel receive (Rx) array for 10.5T brain imaging, comprised of 120 small Rx loops and 8 of the 16 transmitter elements used as receivers. The coil is compared to another 10.5T 64-Rx array and to 7T 32- and 64-Rx arrays. The principal benefit for the same field strength was improved parallel imaging. Secondarily, important engineering innovations are demonstrated to suppress transmit/receive interactions and optimize transmit efficiency. Modest improvements to peripheral SNR were achieved for the 10.5T 128-Rx over 64-Rx array. A 50% improvement in central SNR was realized with the use of transmitter elements as receivers.
Inflatable RF Coil with Liquid Metal for MR Imaging
Authors: Kandala Sri Kirthi , Song Kwanjoon , Sohn Sung-Min
Published: August 2024

In this work, we present a novel inflatable radio-frequency receive coil for Magnetic Resonance Imaging at 7T. A small sample was imaged with and without inflation, and the overall signal-to-noise ratio of the sample was improved by 12.7% in dB with inflation. This coil design will offer many opportunities in the field of endorectal imaging, imaging for irregular sample shapes, and reducing motion artifacts. Inflation also changes the tuning and matching conditions, which compensate for loading effects by precisely adjusting the air volume inside the cavity.
Toward accurate cerebral blood flow estimation in mice after accounting for anesthesia
Authors: Wei Zhiliang , Li Yuguo , Bibic Adnan , Xu Jiadi , Lu Hanzhang
Published: August 2024

CBF measurements in mice were often confounded by the utilizations of anesthesia, which are generally vasoactive. Here, we aimed to systematically understand the relationships between CBF and related physiological factors, not only the anesthesia dose but also respiratory rate (RR), heart rate (HR), and exposure time to anesthesia. We found that CBF measurements in mice were affected by anesthesia dose and time, but can be corrected by using respiratory rate and heart rate. The correction scheme will facilitate applications of CBF measurements in mechanistic understanding of vascular diseases and preclinical therapeutic trials by providing anesthesia-independent CBF measurements.
Validation of Non-Invasive Relative Pressure Mapping by 4D Flow MRI in Aortic Dissection
Authors: Hardy Brandon , Zimmermann Judith , Burris Nicholas , Ennis Daniel , Marlevi David , Nordsletten David
Published: August 2024

False lumen (FL) growth rate in type B aortic dissection (TBAD) is correlated with FL pressurization. 4D flow MRI allows for quantitative assessment of three-dimensional flow, including spatial mapping of relative pressure. Despite its promise, 4D flow relative pressure mapping has not yet been validated in a TBAD-specific context. Here, we validate a state-of-the-art proposed Stokes Estimator (STE) of relative pressure against catheter measurements using three physiologically accurate TBAD flow phantoms and subsequently analyze the method’s sensitivity to image noise. STE pressure estimates closely matched catheter data and were robust to noise, indicating STE’s potential for TBAD treatment planning.
Motion artifact reduction in self-gated CMR 4D flow imaging under exercise stress
Authors: Arshad Syed Murtaza , Chen Chong , Liu Yingmin , Chandrasekaran Preethi , Crabtree Christopher , Jin Ning , Ahmad Rizwan
Published: August 2024

Free-breathing self-gated CMR 4D flow imaging using traditional Compressed Sensing (CS) methods invariably contains motion artifacts due to the inaccuracy of self-gating signal. Self-gating signal degrades even further in the case of exercise stress imaging due to excessive movement of the subject. We propose Compressive recovery with Outlier Rejection (CORe) to reduce the motion artifacts. Using data from a 2D digital phantom and 4D flow data under rest and stress conditions, we demonstrate that CORe is effective in suppressing motion artifacts while maintaining agreement with 2D-PC based flow quantification.
Diving into Extended Phase Graph-based Deep Learning for accurate T2 mapping with PENGUIN
Authors: Carvalho Catarina , Correia Teresa , Nunes Rita
Published: August 2024

Model-based deep learning approaches have shown promising results to accelerate T2 relaxometry, but most adopt a pure exponential curve to model the signal, which does not account for indirect and stimulated echoes. A PhasE graph sigNal and Gradients QUantitative Inference MachiNe (PENGUIN) is proposed, which implements a dictionary of pre-calculated echo-modulation curves following the Extended Phase Graph (EPG) formulation and respective gradients as the inputs of a Recurrent Inference Machine to perform accurate T2 mapping from the reconstructed images. PENGUIN is 25-fold faster than a pattern recognition approach with a T2 dictionary step of 2 ms.
Towards isotropic 3D whole-heart T1 mapping using model-based motion-corrected super-resolution reconstruction
Authors: Hufnagel Simone , Schuenke Patrick , Schulz-Menger Jeanette , Schaeffter Tobias , Kolbitsch Christoph
Published: August 2024

Cardiac T1 mapping provides valuable information for the diagnosis of a variety of heart diseases. However, due to SNR and scan time limitations, often only 2D imaging with a low through-plane resolution covering a few slices of the left ventricle is possible. In this work, a super-resolution reconstruction approach is presented aiming towards whole-heart 1.3 mm isotropic T1 mapping within less than three minutes acquisition time. The proposed approach provided a whole-heart cardiac T1 map including the atria and the right ventricle with improved visualization of small structures and overall image quality.