bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating VoxelMorph Image Registration for Fast 4D Respiratory Compensated Image Reconstruction on an MR-Linac
Authors: Goodburn Rosie , Dassanayake Movindu , Lecoeur Bastien , Nair Prashant , Oelfke Uwe , Wetscherek Andreas
Published: August 2024

Respiratory resolved (4D)-MRI is expected to benefit MRI-guided radiotherapy for abdominal-thoracic cancers. However, a current limitation of 4D-MRI is that one has to trade-off between artefacts, spatial-temporal resolution, and spatial coverage. Deformable image registration has been employed to enhance image quality of undersampled 4D-MRIs, but such approaches are usually too slow to be used in MR-guided radiotherapy workflows. We investigated the feasibility of employing models trained using the VoxelMorph framework with a view of leveraging a fast computation to minimise 4D-MRI reconstruction time on the MR-Linac. The models performed well and were ~48 times faster than a common registration method.
Pre-treatment hyperpolarized 13C-lactate to 13C-bicarbonate ratio predicts response of brain metastases to stereotactic radiosurgery
Authors: Cappelletto Nicole , Soliman Hany , Lee Casey , Bragagnolo Nadia , Uthayakumar Biranavan , Sahgal Arjun , Chen Albert , Endre Ruby , Ma Nathan , Perks William , Detsky Jay , Heyn Chris , Cunningham Charles
Published: August 2024

Brain metastases are increasingly being treated with stereotactic radiosurgery; however, 20-30% of treated tumors locally recure post treatment. Hyperpolarized [1-13C]pyruvate magnetic resonance imaging (HP 13C MRI) is an emerging metabolic imaging modality that measures key metabolic phenotypes indicative of aggressive tumor phenotypes. Here we show that the pre-treatment tumor 13C-lactate to 13C-bicarbonate ratio – a marker of glycolysis and (indirectly) oxidative phosphorylation – measured via HP [1-13C]pyruvate MRI is a robust predictor of local recurrence (AUCROC=0.95, p=0.0008; AUCPRC=0.92) and can inform treatment decisions should the model predict a non-response to SRS.
First in vivo experiences with [1-13C]-pyruvate hyperpolarized by SABRE
Authors: Theis Thomas , Browning Austin , MacCulloch Keilian , TomHon Patrick , Dedesma Carlos , Goodson Boyd , Rosen Matthew , Chekmenev Eduard , Guarin-Bedoya David , Yen Yi-Fen
Published: August 2024

We present the first in vivo hyperpolarized MR using Signal Amplification By Reversible Exchange.
Over 20% 13C-Hyperpolarization and Fast Imaging of Ethyl-[1-13C]-Acetate-d6 and Ethyl-[1-13C]-Pyruvate-d6 using SAMBADENA
Authors: Mohiuddin Obaid , de Maissin Henri , Herzog Marvin , Pravdivtsev Andrey , Brahms Arne , Chekmenev Eduard , Herges Rainer , Hövener Jan-Bernd , Zaitsev Maxim , von Elverfeldt Dominik , Schmidt Andreas
Published: August 2024

Parahydrogen is a cost-efficient source of spin order for high-throughput production of hyperpolarized contrast agents. The parahydrogen approach SAMBADENA has shown great potential for biomedical applications: agents are polarized in situ in the MRI system at low cost with little additional hardware, repeatedly every 15s, and administration in vivo has been demonstrated. Here we present a new setup and high 13C polarization of 28% or 19% for ethyl-[1-13C]-acetate-d6 and ethyl-[1-13C]-pyruvate-d6, respectively, at concentrations of up to 80mM. We envision SAMBADENA to become a versatile method for the widespread application of hyperpolarized MRI and high throughput metabolic 13C MRI studies.
Interactive Real-Time MRI with BART
Authors: Schaten Philip , Uecker Martin
Published: August 2024

The open-source software tool BART provides various state-of-the-art image reconstruction algorithms for MRI. We add an interface for streaming image and k-space data to BART, which should facilitate the application of modern image reconstruction to real-time MRI. Our implementation matches the requirements of interventional MRI in terms of frame rate and latency. Furthermore, we present an intuitive way of interactive slice positioning for MR-guided Interventions using a game controller featuring an inertial measurement unit.
Cerebrovascular reactivity is a predictor of small vessel disease severity after one year in patients with mild stroke
Authors: Sleight Emilie , Stringer Michael , Clancy Una , Arteaga Carmen , Garcia Daniela Jaime , Hewins Will , Jochems Angela , Penman Rachel , Cheng Yajun , Liu Dillys , Zhang Junfang , Hamilton Iona , Jardine Charlotte , Brown Rosalind , Sakka Eleni , Kampaite Agniete , Wiseman Stewart , Valdes-Hernandez Maria , Chappell Francesca , Doubal Fergus , Marshall Ian , Thrippleton Michael , Wardlaw Joanna
Published: August 2024

Small vessel disease (SVD) causes stroke and dementia, but its pathogenesis remains poorly understood. We measured cerebrovascular reactivity (CVR) in SVD patients with minor stroke using 3T BOLD MRI and investigated its relation to baseline and progression of SVD features after one year adjusting for age and vascular risk factors. Patients with lower CVR had higher baseline white matter hyperintensity (WMH) volume, more lacunes and microbleeds and lower brain volume. After one year, patients with lower baseline CVR had increased WMH burden. In conclusion, CVR impairment in SVD patients is associated with higher SVD burden and predicts worsening of SVD.
White Matter Reactivity to Hemodynamic Stimuli: Insights from Dynamic and Maximal Cerebrovascular Reserve after Acetazolamide Provocation
Authors: Gee James , Wang Xiuyuan , Dogra Siddhant , Veraart Jelle , Ishida Koto , Qiu Deqiang , Dehkharghani Seena
Published: August 2024

We explored cerebrovascular reactivity (CVR) of white matter in patients with evidence for micro- and macrovascular disease using our previously described Blood Oxygen Level Dependent – acetazolamide paradigm. Subjects consistently demonstrated lower CVR in voxels with microangiopathic white matter when present in hemispheres with coexistent proximal, large-vessel steno-occlusive disease (SOD). The relationship of CVR values in normal appearing white matter and contralateral white matter lesions in patients with unilateral SOD is more complex and warrants further investigation.
The validation of ASL-aCBV measured by Hadamard encoded ASL imaging evaluating moyamoya disease correlative study with 15O-H2O PET-aCBV.
Authors: Kimura Hirohiko , Isozaki Makoto , Ishida Shota , Takei Naoyuki , Fujiwara Yasuhiro , Matta Yuki , Okazawa HIdehikko , Tsujikawa Tetsuya
Published: August 2024

Positron emission computed tomography (PET) has been used for evaluating cerebral blood flow (CBF) in moyamoya disease to diagnose and assess revascularization result for the patient. Using Hadamard encoded method and DANTE vascular suppression, arterial transit time (ATT) and delay corrected both CBF and aCBV could be obtained in clinical setting. This study aimed to clarify whether ASL- aCBV hemodynamically related to PET-V0 obtained from PET data. There was a significant correlation between PET and CBF both on CBF and aCBV. This may suggest that aCBV could become an additional hemodynamic parameter related to aCBV in completely non-invasive way.
In-Vivo Simultaneous Hyperpolarized 129Xe MRI and [15O]-water PET Multi-Modal Imaging: A Proof of Concept Study
Authors: Sembhi Ramanpreet , Fox Matthew , Lim Heeseung , Hicks Justin , Whitehead Shawn , Thiessen Jonathan , Parraga Grace , Ouriadov Alexei
Published: August 2024

In this proof-of-concept study, simultaneous 129Xe-based MRI and [15O]-water PET images were collected and compared from rat brain. For initial validation phase in phantoms, we have dissolved 129Xe in [15O]-water to simultaneously use both imaging modalities and confirm that PET/MRI images reflect the true density of the 15O/129Xe. The comparison results show similarity between both imaging modalities and tracers, moving towards the next step in validating the Xenon imaging technique as a potential for brain perfusion measurement. The acquisitions were carried out using a 3T PET/MRI (Siemens Biograph mMR).
Validate your CEST simulation!
Authors: Schuenke Patrick , Herz Kai , Zu Zhongliang , Yadav Nirbhay , Zeng Qing , Huemer Markus , Stollberger Rudolf , Xu Jiadi , Wang Kexin , Romdhane Feriel , Longo Dario , Perlman Or , van Zijl Peter , Zaiss Moritz
Published: August 2024

Quantitative CEST approaches can provide access to the exchange rate and solute concentration of exchange processes of interest. However, differences in the implementation of underlying Bloch-McConnell simulations will lead to differences in the determined quantitative parameters. Thus, we initiated a platform to compare and validate the CEST simulations from various CEST research groups. In this first comparison of continuous-wave saturation schemes, up to 5 different results for 8 compared simulations were observed. The project is still open for participation and we invite everbody to join the comparison and our planned discussions to finally realize a consensus on CEST simulations.
Removal of lipid artifacts in CEST data using differential analysis with fitted magnetization transfer and lipid signals (DIGITAL)
Authors: Dai Zhechuan , Yong Xingwang , Zhang Jing , Wang Xiaoxia , Li Qing , Sun Yi , Cao Ying , Zhang Jiuquan , Zhang Yi
Published: August 2024

Chemical exchange saturation transfer (CEST) imaging provides important molecular information that can reflect changes in various pathologies. However, applying CEST to lipid-rich organs, such as the breast, is technically challenging, where the lipid artifacts can grossly affect the CEST signal. In this study, we propose a novel differential analysis method with fitted magnetization transfer and lipid contributions (DIGITAL) to remove the lipid artifacts without changing the acquisition sequence. The DIGITAL method was validated on breast cancer patients, and yielded fewer lipid artifacts and better image smoothness than previous analysis-based methods.
MT imaging at 0.55T with GRE and bSSFP
Authors: Leitão David , West Daniel , Tomi-Tricot Raphael , Hajnal Jo , Wood Tobias , Malik Shaihan
Published: August 2024

We used multiband pulses to obtain Magnetization Transfer (MT) weighted images at 0.55T in a time-efficient manner. White Matter (WM)/Grey Matter (GM) contrast is compared across several flip-angles for both GRE and bSSFP sequences. GRE showed larger MTR WM/GM difference but after accounting for signal-to-noise ratio bSSFP had 50% better contrast-to-noise ratio.
End-to-end Automation of Quantitative Processing for 4D Flow MRI in the Aorta: Demonstration and Evaluation in 271 Subjects
Authors: Johnson Ethan , Berhane Haben , Weiss Elizabeth , Sodhi Aparna , Jarvis Kelly , Scott Michael , Robinson Joshua , Rigsby Cynthia , Markl Michael
Published: August 2024

A generalized data-processing pipeline tool for performing completely automated hemodynamic assessment from raw 4D flow MR images is presented. The tool is evaluated for performance in a group of 271 subjects with mixed distribution of healthy, valve disease, and connective-tissue disorder status. A high success rate of 94% is achieved for fully-automated quantification of regional aortic peak velocities and global aortic pulse wave velocity.
Neurite orientation dispersion and density imaging-based texture features in differentiating glioblastoma from solitary brain metastasis
Authors: Zhao Guohua , He Mengyang , Su Yizhou , Lin Yusong , Gao Eryuan , Bai Jie , Ma Xiaoyue , Zhang Huiting , Yan Xu , Yang Guang , Cheng Jingliang
Published: August 2024

Preoperative differentiation between glioblastomas (GBM) and solitary brain metastases (SBM) would aid in appropriate treatment planning and follow-up. Neurite orientation dispersion and density imaging (NODDI) can identify diverse tissue components within tumors. Texture analysis can be used to extract and quantify these tissue inhomogeneities. In this study, we extracted texture features using NODDI and validated the NODDI metric map models and a combination model to discriminate between GBM and SBM. Finally, the combined NODDI model achieved the best discriminative power. Texture analysis based on NODDI has great potential for distinguishing between GBM and SBM.
MRF-mixer: a self-supervised deep learning MRF framework
Authors: Gao Yang , Ding Tianyi , Cloos Martijn , Sun Hongfu
Published: August 2024

Deep neural networks are increasingly employed in MRF reconstruction recently, as an alternative for conventional dictionary matching. However, most previous deep leanring MRF networks were trained based on the dictionary pairs (generated using theoretical bloch equation) or in vivo acquisitions paired with dictionary matching reconstructions (as training labels), whose reconstruction accuracy relies heavily on the dictionary construction and the number of sampling arms. In this work, we propose a self-supversied deep learning MRF method, namely MRF-Mixer, which can result in more accurate MRF reconstructions compared with dictionary matching.
Variation in 8 years Cartilage Loss Trajectories Based on Baseline Pain and Deep Learning-Assessed ROAMES Morphological Phenotypes
Authors: Hess Madeline , Majumdar Sharmila , Pedoia Valentina
Published: August 2024

We find that the presence or absence of ROAMES morphological phenotypes as predicted from MRI is a useful indicator of osteoarthiris progression over 8 years as measured by cartilage thinning.
Permeability mapping in stroke via diffusion Standard Model with Exchange and S/V measurements from high-frequency OGSE
Authors: Shemesh Noam , Alves Rita , Olesen Jonas , Ianus Andrada , Jespersen Sune
Published: August 2024

Membrane permeability plays an important role in numerous physiological processes ranging from cell volume regulation to neural activity. Until now, diffusion MRI measurements mainly provided information on exchange rates; however, to map permeability, information on the surface-to-volume (S/V) ratio is needed. Here, we apply ultrahigh frequency OGSE to infer on S/V from the associated power law dependence (1/ω1/2,) and the Standard Model with Exchange (SMEX) model for extracting the neurite -> extracellular space exchange rates in stroked rat brains. Combined, we present quantitative measurements of permeability which show plausible values and striking contrast in stroke.
Detecting in vivo Mitochondrial Dysfunction with 4D Oxy-wavelet MRI in Kainic Acid Induced Temporal Lobe Epilepsy
Authors: Cortes Devin Raine , Stapleton Margaret , Schwab Kristina , Coulson Noah , West Dalton , Becker-Szurszewski Thomas , Hartwick Sean , Bharathi Sivakama , Goetzman Eric , Kelly Kevin , Christodoulou Anthony , Wu Yijen
Published: August 2024

Intractable temporal lobe epilepsy, often acquired after status epilepticus (SE) injury, greatly reduces quality of life. There is an unmet need for a non-invasive method to track progression from SE to epilepsy, which would allow early intervention to prevent irreversible damage to the brain. Mitochondrial dysfunction is becoming a recognized marker of epileptogenesis. Here, we established a novel functional MRI methodology, the 4D Oxy-wavelet MRI, capable of in vivo detection of mitochondrial dysfunction underlying post-SE epileptogenesis in a spatial specific manner. This non-invasive method may aid early detection of subclinical epileptogenesis and serve as a biomarker for therapeutic efficacy.
Evaluation of glymphatic system function using DTI-ALPS in patients with temporal lobe epilepsy
Authors: Zhao Xu , Zhou Zhiqiang , Zhu Wenzhen
Published: August 2024

The alterations of glymphatic system function in left hemisphere and right hemisphere and the asymmetric features of glymphatic system were not clear in temporal lobe epilepsy (TLE) patients. We investigated the glymphatic system function in TLE patients and evaluated the asymmetric features of glymphatic system by using DTI-ALPS method. Our findings indicated leftward asymmetric tendency of glymphatic system in adult human brain. The abnormality of glymphatic system asymmetry in LTLE was also found. The glymphatic system function was impaired and more severe alterations of glymphatic system in ipsilateral hemisphere than contralateral hemisphere in TLE patients.
Can fMRI metrics lateralize epileptogenic hypometabolic FDG-PET regions? A simultaneous PET/MR investigation in focal epilepsy
Authors: Uher Daniel , Drenthen Gerhard , van de Weijer Tineke , van der Pol Jochem , Rouhl Rob , Schijns Olaf , Colon Albert , Backes Walter , Jansen Jacobus
Published: August 2024

Locally reduced glucose metabolism (i.e. hypometabolism) derived from the 18-FDG positron emission tomography (FDG-PET) is considered to be a valuable biomarker for epileptogenic zone localization. Spontaneous fluctuations in blood-oxygen-level-dependent fMRI (BOLD fMRI) can indirectly measure neuronal activity. Studies have suggested that the fMRI-derived metrics may be indicative of the epileptogenic zone localization, however the potential for fMRI to reflect and lateralize the hypometabolic FDG-PET regions remains underdetermined. Here, both static and dynamic fMRI-derived metrics were calculated and we assessed their potential for lateralizing the hypometabolic FDG-PET regions in patients with unilateral focal epilepsy.
Motion Estimation and Retrospective Correction in 2D Cartesian Turbo Spin Echo Prostate Scans
Authors: Clifford Bryan , Polak Daniel , Lo Wei-Ching , Splitthoff Daniel , Bolster Bradley , Deshpande Vibhas , Harisinghani Mukesh , Huang Susie , Wald Lawrence , Cauley Stephen
Published: August 2024

Non-rigid patient motion is commonly encountered in clinical settings and can degrade the diagnostic quality of MR exams. We apply the SAMER retrospective method for 2D TSE/FSE prostate imaging to quantify and correct for bulk motion in the abdomen. SAMER utilizes a rapid low-resolution scout scan and a small number of calibration samples for separable motion estimation. In controlled phantom and in vivo experiments, SAMER enabled accurate motion parameter estimation across multiple motion patterns. In addition, we demonstrate improved image homogeneity and spatial resolution when SAMER is used for correction of non-rigid motion in the prostate.
Gaining insight into the neural basis of resting-state fMRI signal
Authors: Ma Zilu , Zhang Qingqing , Tu Wenyu , Zhang Nanyin
Published: August 2024

Understanding the relationships between neuronal, vascular and Blood oxygenation level-dependent (BOLD) signals is essential for the appropriate interpretation of functional magnetic resonance imaging (fMRI) results in relation to the corresponding neuronal activity. In this study, we utilized multimodal imaging technique that concurrently measures BOLD fMRI and calcium-based fiber photometry signal to examine the relationship between BOLD and neural spiking activity in awake rats. Our results demonstrated significant correspondence between the BOLD and calcium signals at both evoked and resting state, suggesting critical role of spiking activity in the neural mechanism underlying BOLD signal.
Constrained Dipole Inversion Using Jointly Learned Local Field and Susceptibility Priors
Authors: Peng Xi
Published: August 2024

The inversion of tissue magnetic susceptibility from a single-orientation phase measurement is an ill-posed problem. In this work, we propose a novel learning-based constrained reconstruction to integrate the jointly learned tissue field and susceptibility priors with the physics-based dipole inversion formalism such that the non-Gaussian model biased caused by the substantial errors in the estimated tissue field and the streaking artifacts in the tissue susceptibility can be effectively reduced. An efficient solver was also developed to solve the optimization problem. We demonstrated the superior performance of the proposed method over the state-of-the-art dipole inversion method using in vivo datasets.
Fast Submillimeter QSM for Simultaneous QSM/MRSI of the Brain at 7T
Authors: Guo Rong , Li Yudu , Zhao Yibo , Anderson Aaron , Bhattacharyya Pallab , Lowe Mark , Li Yao , Sutton Brad , Liang Zhi-Pei
Published: August 2024

The feasibility of simultaneous QSM and MRSI has been recently demonstrated using SPICE. But the resolution of QSM obtained by SPICE at 7T is limited to only 3 mm due to bandwidth requirements. To overcome the resolution limitation, this work proposes a fast acquisition sequence for high-resolution encoding, and a model-based method to reconstruct from sparse sampling. As a result, submillimeter QSM can be achieved within only 1 minute, which enables simultaneous QSM (at 0.8 mm) and MRSI (at 3.0 mm) in an 8-minute scan at 7T.
First in vivo results with a modular system of flexible coil arrays for 3 T MRI (ModFlex)
Authors: Nohava Lena , Obermann Michael , Frass-Kriegl Roberta , Soanca Onisim , Laistler Elmar
Published: August 2024

Form-fitting radiofrequency coil arrays have the potential to enhance the signal-to-noise ratio, enable faster imaging and improve patient comfort in MRI. We developed a flexible modular coil array system for 3T MRI (ModFlex) with 16 receive channels. In neck, spine, ankle and hip imaging, we measured an SNR gain for 4 out of 6 anatomical target regions and similar SNR for 2 out of 6 as compared to commercial reference coils. The coil’s versatility is beneficial for different use cases with varying subject sizes.
Evaluation of Coupling between A 32-channel Sleeve Antenna Receiver Array to A 16-channel Loop Transmitter for The Human Head Imaging at 10.5 T
Authors: Woo Myung Kyun , DelaBarre Lance , Waks Matt , Jungst Steve , Nguyen Pat , Lagore Russell , Grant Andrea , Jang Joo Yoon , Sadeghi-Tarakameh Alireza , Eryaman Yigitcan , Ugurbil Kamil , Adriany Gregor
Published: August 2024

We evaluated in simulation and experimentally the effects that the insertion of a 32-channel sleeve antenna receiver array has on the B1+ and SAR performance of a 447 MHz/10.5 T 16-channel loop transmitter array. For this we carefully developed accurate models of both the 16-channel loop transmitter and the 32-channel sleeve antenna receiver, compared simulated with experimental B1+ and evaluated the expected SAR efficiency of the 16-channel loop transmitter array with and without the 32-channel sleeve antenna receiver array insert.
Evaluation of Coaxial Dipole Antennas as Transceiver Elements of Human Head Array for Ultra-High Field MRI at 9.4T
Authors: Solomakha Georgiy , Bosch Dario , Scheffler Klaus , Avdievich Nikolai
Published: August 2024

Arrays of dipole antennas were recently introduced as transceiver RF coils for human head imaging at UHF as a simple and robust alternative to loop arrays. Due to the head size, dipoles should be significantly shorter than λ/2 at working frequency. Short dipoles suffer from high SAR and insufficient brain coverage. In addition, since head arrays are usually placed on rigid holders, the resonance frequency of dipoles change drastically with head size variation. In this work, we developed a coaxial dipole array for human head imaging at 9.4T. The developed coil provides whole-brain coverage, low SAR, and low frequency variation.
A radiofrequency coil for infants and toddlers
Authors: Gilbert Kyle , Nichols Emily , Gati Joseph , Duerden Emma
Published: August 2024

This abstract presents an adjustable RF coil designed for imaging three-month-old infants to three-year-old toddlers, where motion and variance in head size can be detrimental to image quality. The coil is designed with an open face to allow for the use of camera or motion tracking systems. The tailored RF coil produced higher SNR and lower geometry factors than adult coils. Accelerated protocols can now be combined with prospective motion correction, thereby improving the success rate of imaging infant and toddler populations.
Automatic 3D Segmentation of perforating arteries from ultra-high resolution 7T Compressed Sensing MRA images.
Authors: Kong Qingle , Zhang Zhe , Jing Jing
Published: August 2024

The evaluation of perforating arteries is important for the diagnosis of small vessel disease. It’s challenging to image perforating arteries because of their small caliber size, which requires an extremely high resolution. Moreover, to determine pathological changes, the vessel trees need to be segmented and quantified. In this study, an automatic 3D Segmentation method was introduced and perforating arteries around the Circle of Willis were segmented and quantified. The number of stems of perforators was counted and compared based on segmentation results and MIPs images. The results revealed that the segmentation method robustly achieved the segmentation of perforators.
Comparative analysis of image quality by 3.0 T Non-contrast Free-breathing Whole-heart CMRA with CCTA in patients with coronary artery stenosis
Authors: Tian Ping , Liu Ying , Lian Jianxiu , Zheng Minwen , Xu Jingji , Zheng Jianmin
Published: August 2024

Atherosclerotic lesions in coronary vessels cause vascular lumen stenosis or obstruction, resulting in myocardial ischemia, hypoxia or necrosis, which is an important cause of coronary heart disease. This study was designed to evaluate the performance of coronary magnetic resonance angiography(CMRA) sequence in volunteer subjects. The ability visualization of coronary Main Branch segments were no statistically significant difference in MRA coronary quality scores compared with CTA(p＞0.05) with sensitivity, specificity for per patient were 86%, 85%, respectively. The coronary artery visualization by CMRA can be used to detect clinically significant coronary artery stenosis in patients with suspected coronary heart disease.
Improved R2* and QSM mapping for dummies - ask Adam
Authors: Marques José , Hollander Dennis Den , Norris David , Chan Kwok-Shing
Published: August 2024

In this abstract we demonstrate a simple framework that builds up on deep learning infrastructure to perform quantitative susceptibility mapping and correct for susceptibility related effects on R2* maps, taking the advantage of high GPU computational efficiency. Asking the Adam optimizer to point you in the right direction results in a gradient descent method that can perform field mapping, background field removal, QSM and reduce macroscopic intravoxel dephasing artifacts in R2* maps with most operations being performed in under 60 seconds even for 0.8mm isotropic whole brain multi-echo data.
Characterization of the Textural Features from Quantitative MRI for Determination of Cartilage Degeneration
Authors: Juras Vladimir , Toegel Stefan , Hager Benedikt , Schreiner Markus , Janacova Veronika , Szomolanyi Pavol , Laurent Didier , Saxer Franziska , Heule Rahel , Bieri Oliver , Raithel Esther , Fuchssteiner Christoph , Weninger Wolfgang , Windhager Reinhard , Trattnig Siegfried
Published: August 2024

Texture features derived from quantitative MRI maps of cartilage have attracted increasing attention from the osteoarthritis (OA) community in recent years. In this work, texture analysis was used on T2 maps and validated using histological analysis. Some texture features (autocorrelation, contrast and entropy) correlated with the Mankin score; autocorrelation also correlated with collagen orientation calculated from PLM images. The correlation between image-derived features with histological quality scores can be a decisive step towards monitoring of cartilage regeneration in-vivo and help to identify therapies that restore articular cartilage quantity and quality.
Reliable high-resolution in vivo human knee T1ρ imaging quantification with robust fitting methods
Authors: Zhang Zhiyuan , Kim Jeehun , Lartey Richard , Winalski Carl , Li Xiaojuan
Published: August 2024

Quantitative MR T1ρ and T2 imaging are promising methods to detect osteoarthritis at its early stage. Current T1ρ and T2 mapping in human subjects is limited to a relatively low resolution which has limited sensitivity to focal lesions due to partial-volume effects. One of the hurdles to achieving high resolution is the increase in fitting bias when using a conventional nonlinear least-squares fitting with low SNR images. In this study, we evaluated T1ρ quantification with in-vivo high-resolution imaging with different fitting methods.
The apparent orientation dependence of MTR, ihMTR and MWF is affected by local microstructural properties in white matter
Authors: Morris Sarah , Vavasour Irene , Smolina Anastasia , MacMillan Erin , Gilbert Guillaume , Lam Michelle , Kozlowski Piotr , Michal Carl , Manning Alan , MacKay Alex , Laule Cornelia
Published: August 2024

We measured MTR, ihMTR, MWF and fibre orientation from DTI in 17 white matter regions in 17 healthy adults at 3 T. All three metrics showed an apparent orientation dependence: MWF and ihMTR were lower in fibres perpendicular to B0 by 6% and 1% respectively compared to those parallel, while MTR was lower by 0.5% at ~40°, with the highest values in fibres perpendicular to B0. However, separating the apparent orientation dependence by region revealed large variation in the trends, suggesting that real differences in myelination and other microstructural properties are confounding the apparent orientation dependence measured using this method.
Investigating spinal cord perfusion impairment in degenerative cervical myelopathy (DCM) using Intravoxel Incoherent Motion (IVIM) MRI
Authors: Lebret Anna , Lévy Simon , Pfender Nikolai , Farshad Mazda , Callot Virginie , Curt Armin , Freund Patrick , Seif Maryam
Published: August 2024

Degenerative cervical myelopathy (DCM) is the most common form of non-traumatic spinal cord injury, mainly caused by chronic cervical cord compression. Impaired spinal cord perfusion is a central pathophysiological tenet in DCM patients. This study aims at investigating non-invasively DCM-induced changes of blood perfusion in the spinal cord above a cervical myelopathy using quantitative MRI techniques. Cardiac-gated intravoxel incoherent motion (IVIM) 3T MRI, sensitive to perfusion, was applied to the cervical cord (C1-C3) in 25 DCM patients and 27 healthy controls. DCM showed tissue-specific perfusion impairment. IVIM maps suggested remote hemodynamic deficit induced by cervical cord compression in DCM.
Feasibility of automatic patient-specific sequence optimization with deep reinforcement learning
Authors: Terpstra Maarten , Verschuren Sjors , Bruijnen Tom , Maspero Matteo , van den Berg Cornelis
Published: August 2024

For MRI-guided interventions, tumor contrast and visibility are crucial. However, the tumor tissue parameters can significantly vary among subjects, with a range of T1, T2, and proton density values that may cause sub-optimal image quality when scanning with population-optimized protocols. Patient-specific sequence optimization could significantly increase image quality, but manual parameter optimization is infeasible due to the high number of parameters. Here, we propose to perform automatic patient-specific sequence optimization by applying deep reinforcement learning and reaching near-optimal SNR and CNR with minimal additional acquisitions.
Federated MRI Reconstruction with Deep Generative Models
Authors: Elmas Gokberk , Dar Salman , Korkmaz Yilmaz , Ozbey Muzaffer , Cukur Tolga
Published: August 2024

Generalization performance in learning-based MRI reconstruction relies on comprehensive model training on large, diverse datasets collected at multiple institutions. Yet, centralized training after cross-site transfer of imaging data introduces patient privacy risks. Federated learning (FL) is a promising framework that enables collaborative training without explicit data sharing across sites. Here, we introduce a novel FL method for MRI reconstruction based on a multi-site deep generative model. To improve performance and reliability against data heterogeneity across sites, the proposed method decentrally trains a generative image prior decoupled from the imaging operator, and adapts it to minimize data-consistency loss during inference.
Capillary-weighted velocity-selective ASL for subsecond fast fMRI
Authors: Gomez Daniel , Lewis Laura , Polimeni Jonathan , Bolar Divya
Published: August 2024

This work evaluates capillary-weighted VS-ASL for subsecond functional cerebral blood flow (CBF) mapping with high microvascular specificity. Three experiments were conducted: one to demonstrate that capillary-weighted VS-ASL is mostly free from macrovascular contamination when compared to arterial-weighted VS-ASL, one to demonstrate that functional MRI is feasible with capillary-weighted VS-ASL at moderate repetition times, and one to show that, despite lower sensitivity, capillary-weighted functional MRI can be performed at subsecond temporal resolution. Our findings suggest that capillary-weighted VS-ASL may enable the study of fast functional CBF responses with high neuronal specificity.
Quantitative transport mapping (QTM) of the brain with simulated microvasculature model
Authors: Hu Renjiu , Zhang Qihao , Romano Dominick , Wang Yi
Published: August 2024

We compared the quantitative mappings on the simulated the brain arterial spin labeling images with artificial microvasculature structures and perfusion properties. The QTM method gives similar quantification on blood flow as the traditional tracer kinetic model.
Pathogenesis of Chiari Malformation:insights from morphology,neurobiology and hydrodynamics based on MR neuroimaging technology
Authors: Wang Yishuang , HE Yun sen , Chen Meining , Wang Yuting , Yin Longlin
Published: August 2024

The pathogenic mechanism of different clinical and radiologic manifestations of Chiari malformation I (CMI) is still unclear. Using MR morphology, neurobiology, and hydrodynamics techniques allow for a comprehensive assessment of CMI. FA values and CSF flow may well explain the correlation between white matter fiber tract, CMI pain, and compensations at other body parts. MRI technology helps us to better understand the pathogenic mechanism of CMI and can provide more valuable information in the diagnosis and treatment of CMI.
Multiparametric Quantitative MRI of Peripheral Nerves: A Reliability Study
Authors: Chen Yongsheng , Baraz Jacob , Xuan Stephanie Yan , Castoro Ryan , Xuan Yang , Roth Alison , Dortch Richard , Li Jun
Published: August 2024

This study developed a multiparametric qMRI method to quantify fat fraction of leg muscles, myelin and axonal pathologies of peripheral nerves using MTR, MTsat, T1, PD, T2*, FA, MD, AD, RD, and nerve fascicular volume. The results will be applied in ongoing longitudinal studies to develop monitoring biomarkers in patients with polyneuropathies.
Functional brainstem imaging of sympathetic drive using MSNA coupled fMRI and SSNA coupled fMRI at ultra-high field.
Authors: Glarin Rebecca , Henderson Luke , Rim Donggyu , Macefield Vaughan
Published: August 2024

Muscle sympathetic nerve activity (MSNA) is responsible for blood pressure control and skin sympathetic nerve activity (SSNA) for thermoregulation. This activity can be recorded through a process of microneurography. This nerve activity can be temporally coupled with fMRI to image the brainstem. With the use of ultra high field MRI we are able to image the subcortical and cortical regions responsible for these sympathetic nervous system processes. Brainstem imaging using this technique for the first time at high field, has identified with high specificity the rostral ventrolateral medulla (RVLM) when using MSNA coupled fMRI.
Predicting microvascular invasion of HCC using whole-lesion histogram analysis with the interstitial fluid pressure and velocity model
Authors: Zheng Liyun , Yang Chun , Dai Yongming , Zeng Mengsu
Published: August 2024

Most solid tumors have increased interstitial fluid pressure (IFP), and the increased IFP is an obstacle to treatment. This study applied a non-invasive dynamic contrast-enhanced magnetic resonance imaging-based model to acquire IFP and interstitial fluid velocity (IFV). Based on the IFP and IFV maps, histogram analysis was applied to evaluate the spatial distributions of pixel gray levels with reduced sampling bias. IFP- and IFV-derived parameters have proven to be significant predictors of microvascular invasion status. Therefore, this optimal model, together with histogram analysis, offers a new way for in vivo and non-invasive assessment of hepatocellular carcinoma.
The value of glucose-chemical exchange saturation transfer and amide proton transfer in predicting tumor grading and staging in rectal cancer
Authors: Jiang Han , Meng Nan , Li Ziqiang , Dai Bo , Feng Pengyang , Luo Yu , Shen Zhiwei , Wang* Meiyun
Published: August 2024

What are the values of glucose-chemical exchange saturation transfer (glucoCEST) and amide proton transfer (APT) imaging in WHO grading and T staging of rectal cancer? We performed 3D-glucoCEST, 3D-APT, and DWI scans in 21 rectal adenocarcinoma cases. GlucoCEST signal intensity (SI) and 3D-APT SI could distinguish high-grade from low-grade, and T3 stage from T2 stage rectal adenocarcinoma, and both had comparable diagnostic efficacy. In addition, 3D-glucoCEST SI and 3D-APT SI were positively correlated with tumor grade.
Quantitative and Automated MRI Cancer Risk Maps used for Identification of Prostate Cancer Progression
Authors: Gibbons Matthew , Cowan Janet , Carroll Peter , Cooperberg Matthew , Noworolski Susan
Published: August 2024

This study’s objective was to determine whether automated mpMRI cancer risk maps could identify prostate cancer progression during active surveillance. Derived lesion masks were used to analyze factors for progression. A decision tree model for progression was generated with sensitivity = 0.84, specificity = 0.56, and ROC AUC 0.75. The identification results indicate the potential of mpMRI and MRI cancer risk maps to assist in identifying progression during prostate cancer active surveillance.
Accelerating beyond the sound limit: Ultrasonic Wave-CAIPI using a dual-axis head gradient insert
Authors: Roos Thomas , Siero Jeroen , Klomp Dennis , Wienke Matthias , Wijnen Jannie , Versteeg Edwin
Published: August 2024

In this work, we present peripheral nerve stimulation and imaging results for a dual-axis head gradient that operates at ultrasonic frequencies. PNS measurements on 4 volunteers did not yield any noticeable stimulation. Imaging was performed using an ultrasonic Wave-CAIPI MP-RAGE, which featured ~20-fold acceleration and fully-sampled K-space coverage. We show the first images with this approach and a g-factor close to unity.
Prospective Compensation of Second-order Concomitant Fields in a High-performance Gradient System using a Second Order Harmonic Shim Coil
Authors: Ajala Afis , Lee Seung-Kyun , Abad Nastaren , Hua Yihe , Foo Thomas
Published: August 2024

The use of higher-performance gradient coils results in stronger second-order concomitant magnetic fields, which can lead to image artifacts such as signal dropout, blurring, and phase errors that cannot be corrected by pre-emphasis of gradient waveforms and/or radio frequency modulation alone. We have developed an axially symmetric second-order field coil that is insertable, and demonstrate its ability to prospectively correct the additional phase generated by second-order concomitant fields in 2D phase contrast and spiral-out gradient echo imaging in a 3.0 T high-performance head-gradient (MAGNUS) system.
Universal modes: Calibration-free TIAMO for B1+ inhomogeneity mitigation
Authors: Schmidt Simon , Metzger Gregory
Published: August 2024

In this work we introduce the concept of universal modes, which consists of the application of the universal pulse concept to time interleaved acquisition of modes (TIAMO). Based on simulated B1+ maps of a 16-channel body array at 10.5T, the ability to mitigate B1+ inhomogeneities is successfully demonstrated in six different human body models, targeting the pelvis.
Overcoming system imperfections using end-to-end MR sequence design.
Authors: West Daniel , Glang Felix , Endres Jonathan , Zaiss Moritz , Hajnal Jo , Malik Shaihan
Published: August 2024

MRI systems are usually engineered to give 'ideal' performance, and acquisition methods are generally developed using this assumption. This work proposes an alternative sequence learning framework that includes a model of realistic scanner performance, allowing acquisition sequences to be designed to directly account for system imperfections. In this proof-of-concept demonstration we designed pulse sequences to account for eddy current perturbations with different realistic time constants, while also respecting hardware limits. The flexibility of this approach could be used to design new types of pulse sequence to operate on lower performance, lower cost hardware in future.
Real-time fetal cardiac MRI at 0.55T enables assessment of ventricular function and heart and great vessel anatomy
Authors: Tian Ye , Detterich Jon , Pruetz Jay , Joshi Anand , Wood John , Nayak Krishna
Published: August 2024

We demonstrate a real-time spiral balanced steady-state free precession (bSSFP) pulse sequence for fetal cardiac examinations on a 0.55T scanner. The real-time sequence provides easy adjustments of scan plan, automatic volumetric sweeping covering the whole heart, and flexible choice of reconstruction temporal resolution, without relying on any maternal breath-hold or cardiac gating. In 9 experiments involving 8 volunteers, we demonstrated high-temporal resolution (40ms/frame) real-time videos that capture fetal cardiac dynamics, and low-temporal resolution (320ms/frame) volumetric images that capture cardiac anatomy. This approach provides both functional and structural evaluations of the fetal heart.
Automated atlas-based craniofacial biometry for 3D fetal MRI: multi-acquisition comparison of fetuses with Down syndrome and a control cohort.
Authors: Matthew Jacqueline , Uus Alena , Fukami-Gartner Abi , Grande Lucillio Cordero , Kyriakopoulou Vanessa , Cromb Daniel , Wright Robert , O'Muircheartaigh Jonathan , Baburamani Ana , Malamateniou Christina , Hutter Jana , Hajnal Joseph , Rutherford Mary , Deprez Maria
Published: August 2024

We introduce the first automated atlas-based method for fetal craniofacial biometry. Using motion-corrected slice-to-volume reconstructions for 3D fetal head visualisation, an automated label propagation method extracted linear biometry across 12 measures. The optimisation process used retrospective data and no differences in automated biometry was seen between different MRI acquisition parameters. A comparison of measures made between a cohort of fetuses with Down syndrome and control fetuses, with normal development, found significant differences for the occipitofrontal skull, oral hard palate and anterior base of skull distances. This suggests a promising and meaningful method for large population-level investigation of MRI craniofacial morphology.
Subject-specific detection of macro- and micro-structural alterations of deep gray matter nuclei using submillimeter 7T quantitative MRI
Authors: Piredda Gian Franco , Cabane Alexandre , Caneschi Samuele , Hilbert Tom , Bonanno Gabriele , Troalen Thomas , Ranjeva Jean-Philippe , de Rochefort Ludovic , Seiffge David , Goeldlin Martina , Hoepner Robert , Wiest Roland , Radojewski Piotr , Kober Tobias , Le Troter Arnaud , Maréchal Bénédicte
Published: August 2024

High-resolution 7T MRI allows to directly visualize deep gray matter nuclei (DGN), especially within the thalamus, and building reference ranges of volumes and relaxation times for these structures is of clinical relevance. Methods to automatically segment DGN at 7T have been recently proposed. In this study, we segmented DGN from a cohort of 132 healthy subjects scanned with the MP2RAGE at 7T to obtain both T1-weighted images and T1 maps. Reference ranges of volumes and T1 values were established and proved valuable in revealing both macro- and micro-structural tissue alterations in selected cases of patients with neurodegeneration.
Somatosensory-evoked fMRI with chemogenetic modulation reflects behavioral normalization in hypersensitized mice
Authors: Jung Won Beom , Lee Soowon , Im Geun Ho , You Taeyi , Kim Eunjoon , Kim Seong-Gi
Published: August 2024

The fMRI mapping with selective modulation of local neural population at the manipulated region is a powerful approach that can causally link circuit-specific interactions to behavioral performance. However, most fMRI studies combined with chemogenetics were conducted in the resting state, which is difficult to elucidate whether and how differences in functional activity by neuromodulation induce behavioral changes. Here, we demonstrated the effects of fMRI-guided focal chemogenetic modulation on both somatosensory-evoked network and its relevant behaviors in mice.
Implantable Coils Enable High-Resolution Functional MRI in Awake Mice
Authors: Hike David , Liu Xiaochen , Xie Zeping , Zhang Bei , Yang Wenchao , Murstein Alyssa , Liu Andy , Glen Daniel , Reynolds Richard , Yu Xin
Published: August 2024

This study utilizes implantable RF coils affixed to mouse heads which are used as head fixation points to minimize motion and remove B1-related artifacts due to motion-induced loading change during scanning. This method increases SNR significantly and enables high-resolution EPI-based functional imaging in awake mice at 14T, highlighting both cortical and subcortical activation following visual and whisker stimulation. Furthermore, this high-resolution awake mouse fMRI setup enables high sensitivity to map brain activation from subcortical nuclei and extends the detection of associated brain regions related to the stimulation.
A complete cerebellar mean-field model ready to be integrated into whole-brain dynamic simulators
Authors: Lorenzi Roberta , Geminiani Alice , Zerlaut Yann , Destexhe Alain , Kingshott Claudia Gandini Wheeler , Palesi Fulvia , Casellato Claudia , D'Angelo Egidio
Published: August 2024

Whole-brain dynamics can be reproduced in silico by simulating Blood Oxygen Level Dependent (BOLD) signals, typically recorded with fMRI, using cortical and subcortical mean-field models, which provide a population-level description of the underlying neuronal dynamics. Notably, a mean-field model specific for the cerebellum is missing given its structural and functional specific properties. We present the first biologically-grounded cerebellar mean-field model optimized on experimental data. Our model reproduces cerebellar activity and synaptic mechanisms characterizing physiological and pathological conditions. The cerebellar mean-field model is a new device ready to be integrated in whole-brain dynamic simulator, improving understanding of brain function and dysfunction.
Quality Control of MRI-based Kidney Volume Estimation in ADPKD patient in clinical practice
Authors: Zhu Chenglin , Sharbatdaran Arman , Dev Hreedi , He Xinzi , Blumenfeld Jon , Chevalier James , Shimonov Daniil , Prince Martin
Published: August 2024

Total kidney volume (TKV) is a critical biomarker for monitoring disease severity in autosomal dominant polycystic kidney disease (ADPKD). TKV is typically measured by manually contouring kidneys on one sequence from abdominal MRI without any quality control. Here we show that by using a deep learning model to measure kidney volume on 5 routinely acquired abdominal MRI sequences, it is possible to apply outlier analysis to find images with acquisition artifacts and to correct or exclude them from TKV estimation. This improves volume measurement consistency among the 5 sequences from 4.3% to 1.3% after quality control.
Initial Experience of Hyperpolarized [1-13C]pyruvate MRI in Kidney Transplant Patients
Authors: Liu Xiaoxi , Lai Ying-Chieh , Kung Shiang-Cheng , Park Meyeon , Zoltan Lazik , Larson Peder , Wang Zhen
Published: August 2024

We present our initial experience of applying hyperpolarized (HP) [1-13C]pyruvate MRI in three patients with renal allograft. The pyruvate metabolism to lactate and bicarbonate in two patients with well functioning allografts and normal biopsy was in the range of healthy native kidneys. The allograft pyruvate metabolism in the third patient with reduced eGFR was higher than that of healthy native kidneys. Study is ongoing to establish the range of pyruvate metabolism in normal allografts and to correlate pyruvate metabolism to allograft biopsy. This study paves the way for investigation of HP MRI in the noninvasive assessment of kidney allograft injury.