bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo simultaneous proton resonance frequency shift thermometry and single reference variable flip angle T1­ measurement
Authors: Richards Nicholas , Odeen Henrik , Johnson Sara , Parker Dennis , Payne Allison
Published: August 2023

Simultaneous proton resonance frequency shift thermometry and T1 measurements were obtained in an in vivo rabbit model using the single reference variable flip angle method. Focused ultrasound was used to heat tissue volumes of muscle and volumes at the fat/muscle interface. Temporal resolution for PRF shift temperatures and T1 changes was 1.71 s. Peak heated muscle voxels showed an increase in T1 of 1.6%/°C. T1 increases were observed in fat at or near the ultrasound focus.
Improving Diffusion MRI in the Posterior Fossa Using a Wireless RF Array at 7T
Authors: Alipour Akbar , Qadi Ameen Al , Verma Gaurav , Seifert Alan , Balchandani Priti
Published: August 2023

Ultra-high field (UHF ≥7T) MRI scanners can provide stronger signals than standard field strengths, which boosts signal-to-noise ratio (SNR) for improved diffusion MRI (dMRI). However, at 7T, wavelength effects cause highly inhomogeneous $$$B_1^+$$$ in the human brain, with lower transmit efficiency in the cerebellum and temporal lobes manifesting as signal dropouts in these regions. Recently, we reported a simple approach of using a wireless radiofrequency (RF) array to improve transmit efficiency and signal sensitivity at 7T focusing on the posterior fossa. Here we demonstrate the feasibility and effectiveness of using the RF array for in-vivo dMRI at 7T.
Laminar VASO fMRI in hand dystonia patients
Authors: Horovitz Silvina , Kassavetis Panagiotis , Hallett Mark , Huber Renzo
Published: August 2023

Mesoscopic fMRI with CBV-sensitive VASO can be a valuable tool for research questions on affected neural processing in patients suffering from neurological diseases. However, its applicability in patient populations remains unclear and is challenged by multiple methodological constraints. Here, we seek to use finger tapping tasks in hand dystonia patients to map affected topographical and laminar fMRI features. Specifically, we described the input-dominated laminar input-output circuits in the primary motor system as well as the ‘scrambled’ finger representations in the somatosensory areas. We built and validated an acquisition and analyses setup for laminar and columnar mapping in patient populations.
Using ultra-high field fMRI to uncover depth-dependent activation in the ventral temporal lobe
Authors: Dowdle Logan , Ghose Geoffrey , Chen Clark , Uğurbil Kâmil , Yacoub Essa , Vizioli Luca
Published: August 2023

We used 7T BOLD functional imaging to acquire 0.7mm voxels and the thermal noise suppression technique NORDIC to evaluate depth-dependent, task related top-down modulations. Four participants viewed face stimuli and performed either a face or fixation task (identical stimuli). We compared depth-dependent task modulations in the primary visual cortex (V1) and fusiform face area (FFA). We found that, relative to the fixation task, face detection led to larger modulations in outer relative to inner layers in the FFA, and the inverse pattern in V1. This is a critical step towards using laminar analyses to examine hierarchical or distributed cognitive processes.
Laminar and columnar functional organization of human area MT using VASO at 7T
Authors: Pizzuti Alessandra , Huber Renzo , Gulban Omer , Benitez-Andonegui Amaia , Peters Judith , Goebel Rainer
Published: August 2023

We investigate the feasibility of using CBV-sensitive VASO fMRI at ultra-high field to study the selective columnar organization to axes of motion stimuli in human area MT.

For 5 subjects we found:

BOLD and VASO both reveal characteristic tuning curves for axes of motion.

VASO is more specific and less sensitive than BOLD.

VASO layer profiles are less distorted by superficial veins than BOLD.

Columnar analysis is feasible using VASO.
Neurophysiological source of laminar fMRI
Authors: Jung Won Beom , Jiang Haiyan , Kim Seong-Gi
Published: August 2023

Layer-dependent fMRI mapping provides insights to understand the directional information flow within brain networks. However, it is unknown whether larimar fMRI responses allows discrimination of activation to cortical input and/or output. To determine neuronal source of hemodynamic fMRI signals, we investigated the somatosensory-evoked laminar fMRI responses and cortical depth-dependent electrophysiological activities in the mouse cortex.
Brain GABA and glutathione measurements in convalescent COVID-19 subjects
Authors: Saleh Muhammad , Chang Linda , Liang Huajun , Ryan Meghann , Cunningham Eric , Wilson Eleanor , Levine Andrea , Kottilil Shyamasundaran , Ernst Thomas
Published: August 2023

COVID-19 infection was associated with lower plasma levels of glutathione (GSH), provoking oxidative stress; however, whether GSH levels are also lower in the brain is unknown. COVID-19 survivors (COVID+) also have higher prevalence of psychiatric disorders, possibly due to altered brain GABA. However, brain GABA and GSH levels have not been assessed in convalescent COVID-19 (COVID+) individuals. Using edited MRS, frontal grey matter (FGM) GSH were lower in male COVID+, and COVID+ individuals had greater age-related decline in FGM GSH, compared to uninfected controls. These findings suggest that male COVID+ individuals, especially the older subjects, are susceptible to oxidative stress.
Global network disruption in focal to bilateral tonic-clonic seizures.
Authors: Maher Christina , D'Souza Arkiev , Barnett Michael , Kavehei Omid , Nikpour Armin , Wang Chenyu
Published: August 2023

Focal to bilateral tonic-clonic seizures (FBTCS) are a feature of focal epilepsy, characterised by seizures that spread contralaterally to the origin of ictal discharge. Widespread global network disruption has been shown in patients with FBTCS compared to those with focal epilepsy. A structure-function relationship has been proposed, suggesting the role of the underlying subcortical structures in network alterations. Disease duration has been associated with whole-brain network disruption. Global network disruption may be a subtle marker in differentiating the likelihood of developing FBTCS, allowing treatment to be tailored.
Relationship between internal carotid artery hemodynamics and cerebrovascular events in moyamoya angiopathy based on 4D Flow MRI
Authors: Wang Maoxue , Zhang Jilei , Zhang Bing
Published: August 2023

Little is known of distal internal carotid artery (ICA) hemodynamics in patients with moyamoya angiopathy (MMA) and its relationship with cerebrovascular events. In this study, distal ICA hemodynamics were analyzed using 4D Flow MRI in 70 MMA patients (61 infarct hemispheres and 63 non-infarct hemipheres). Vmax was found to be associated with cerebrovascular event in MMA patients.
Inflammation and reduced cortical perfusion assessed by renal MRI during acute kidney injury in critically ill COVID-19 patients
Authors: Cox Eleanor , Luther Tomas , Eckerbom Per , Weis Jan , Palm Fredrik , Frithiof Robert , Liss Per , Francis Susan
Published: August 2023

Acute kidney injury (AKI) is associated with increased mortality in COVID-19 patients. Multiparametric MRI was performed to study renal perfusion, oxygenation and tissue structure in nineteen COVID-19 intensive care patients. Results are compared between patients with and without COVID-19 associated AKI, and with healthy volunteers (HV). Cortical perfusion was lower in COVID-19 compared to HVs (P=0.0002) with cortex and medullary perfusion lower in AKI compared to non-AKI (P<0.03). Correlations between cortex measures in COVID-19 showed T1 was positively correlated with T2 and ADC, and T2 was positively correlated with ADC and T2* suggesting interstitial oedema resulting from inflammation.
Lower Cerebral Venous Oxygenation in Post-acute Sequelae of COVID-19
Authors: Liu Peiying , Ernst Thomas , Liang Huajun , Jiang Dengrong , Cunningham Eric , Lin Zixuan , Ryan Meghann , Lu Hanzhang , Wilson Eleanor , Levine Andrea , Chang Linda
Published: August 2023

Post-COVID Syndrome (PCS) is highly prevalent amongst COVID-19 survivors. Neuropsychiatric symptoms are often reported in patients with PCS, suggesting brain involvement in the early stages of COVID-19. One potential etiology is the cerebral microcirculation dysfunction due to SARS-CoV-2 infection, which may affect oxygen delivery and consumption in the brain. In the present study, we investigated the changes in cerebral venous oxygenation, which reflects the balance between oxygen supply and consumption, in convalescent COVID-19 participants with PCS. Our results showed that participants with PCS had altered venous oxygenation in their brain, which was also associated with slower locomotion.
Post-Acute COVID-19 Syndrome: Longitudinal 129Xe MRI Ventilation Heterogeneity Measurements
Authors: Kooner Harkiran , McIntosh Marrissa , Sharma Maksym , Singh Gaurav , Nasir Neha , Blake Emily , Dhaliwal Inderdeep , Nicholson Michael , Kirby Miranda , Parraga Grace
Published: August 2023

Post-acute COVID-19 syndrome (PACS) is an umbrella term for the long-term symptoms and poor quality-of-life that follow acute SARS-CoV-2 viral-infection in up to 7/10 COVID-19 survivors. The mechanistic understanding of PACS remains poorly understood, which stymies treatment decision-making. In a PACS pilot study, we evaluated hyperpolarized 129Xe MRI ventilation defect percent and texture features to measure potential longitudinal changes. There were no significant differences in 129Xe MRI ventilation texture measurements six-months and 12-months after a baseline visit (12 weeks post-infection). PACS participants exhibited abnormal second-order 129Xe MRI ventilation textures and patchy ventilation, relative to healthy controls, 6-12 months post-infection.
The Impact of 3-ply and KN95 Facemasks on Cerebral Blood Flow and Oxygenation
Authors: Fothergill Aisling , Birkl Christoph , Kames Christian , Weber Alexander , Rauscher Alexander
Published: August 2023

Given the increased use of facemasks in everyday life, the impacts of these masks on cerebral blood flow (CBF) and oxygenation needs to be investigated. This study used pseudo-continuous arterial spin labeling (pCASL) and quantitative susceptibility mapping (QSM) to determine changes to grey matter CBF and oxygenation respectively. This was done by comparing facemask and no facemask scans for both 3-ply and KN95 masks. The average percent change between the facemask and no facemask oxygenation/susceptibility were insignificant for both mask types, and only the 3-ply facemask showed a statistically significant increase of 5.5% in CBF when wearing the facemask.
129Xe Gas-Transfer MRI RBC-to-Barrier Ratio in Post-Acute COVID19 Syndrome: Clinically-relevant?
Authors: Matheson Alexander , Kooner Harkiran , Bier Elianna , Lu Junlan , Driehuys Bastiaan , Kirby Miranda , Santyr Giles , Albert Mitchell , Shepelytskyi Yurii , Grynko Vira , Svenningsen Sarah , Ouriadov Alexei , Dhaliwal Inderdeep , Nicholson J , Parraga Grace
Published: August 2023

Post-acute COVID19 syndrome (PACS) is an umbrella term for a syndrome of symptoms persisting at least 12 weeks post COVID19 infection. Preliminary studies in PACS patients post-hospitalization revealed abnormally low 129Xe RBC-to-barrier ratios, but the clinical relevance of this is not well-understood. We acquired 129Xe gas-transfer MRI, spirometry, diffusing-capacity-of-the-lung for carbon-monoxide (DLCO) and same-day CT in 39 participants including 30 PACS and 9 never-COVID19 controls. The 129Xe MRI RBC-to-barrier ratio was significantly related to DLCO and significantly lower in both never-hospitalized and ever-hospitalized PACS patients compared to never-COVID19 controls.
Data-driven optimization of intravoxel incoherent motion imaging for clinical endpoints in radiotherapy on a 1.5 T MR-Linac
Authors: Wetscherek Andreas , McDonald Brigid , Kooreman Ernst , Lau Angus , Paudyal Ramesh , Shukla-Dave Amita , Lawrence Liam , van Houdt Petra , van der Heide Uulke
Published: August 2023

Measuring the detectable effect size is crucial for setting up clinical trials involving quantitative MRI for treatment adaptation, response assessment and outcome prediction in MR-guided radiotherapy. For four different tumor sites (brain, head and neck, prostate and rectum) diffusion-weighted MRI protocols were optimized for intravoxel incoherent motion imaging based on minimizing the mean relative error of the IVIM parameters. For full IVIM model fits, 4-5 b-values were found optimal, while a fit with fixed D* was best performed with 3 b-values. MR-Linac systems currently have limitations regarding gradient performance and number of coil channels and qMRI techniques require careful optimization.
Multi-modal assessment of dose-related changes in regional lung function in non-small cell lung cancer patients receiving radiotherapy
Authors: Tahir Bilal , Hughes Paul , Atkinson Jack , Jadav Isaac , Astley Joshua , Robinson Stephen , Biancardi Alberto , Marshall Helen , Hart Kerry , Swinscoe James , Ireland Rob , Hatton Matthew , Wild Jim
Published: August 2023

Radiotherapy plays a central role in the management of lung cancer. However, despite advances, survival of lung cancer patients undergoing radiotherapy remains poor, partly attributable to the incidence of radiation-induced lung injury, which is exacerbated in patients with poor pulmonary function. Both ventilation and perfusion information are vital to providing a complete picture of pulmonary function, ideally in a regional fashion. Here, we develop and apply an image acquisition and analysis pipeline to assess dose-related changes in regional lung function as derived from hyperpolarized gas ventilation and dynamic contrast-enhanced perfusion MRI in lung cancer patients receiving a course of radiotherapy.
Cross-sectional robustness of 6 freely available software packages for brain volume measurements in multiple sclerosis
Authors: van Nederpelt David , Amiri Houshang , Mariyampillai Amanda , Brouwer Iman , Noteboom Samantha , Barkhof Frederik , Kuijer Joost , Vrenken Hugo
Published: August 2023

Automated segmentation of brain MR images has paved the way for large cohort atrophy studies in multiple sclerosis (MS). A variety of automated software packages is available. Here we aimed to quantify brain volume differences measured by six freely available software packages on data from 21 MS patients all scanned thrice on three different MR scanners. While intra-class correlation coefficients were high, systematic differences between scanners were found for every software. This suggests that direct comparison of volumes acquired with different scanners is not possible and standardization is needed.
Free-Breathing MR Elastography of the Kidneys Using TURBINE-MRE
Authors: Sui Yi , Li Jiahui , Zhu Zheng , Glaser Kevin , Owusu Nana , Trzasko Joshua , Arani Arvin , Yin Ziying , Rossman Phillip , Yin Meng , Ehman Richard
Published: August 2023

A free-breathing hybrid radial-cartesian 3D MR elastography technique (TURBINE-MRE) was extended for kidneys with a dual driver system. This technique provides wave images and stiffness maps in a single 3.5-minute free-breathing acquisition. The feasibility of the new technique was demonstrated in a healthy volunteer.
Numerical simulation of wave propagation through interfaces using the eXtended FEM for MR elastography
Authors: DU Quanshangze , LAMBERT Simon Auguste , HAMILA Nahiène , BEL-BRUNON Aline
Published: August 2023

The finite element method (FEM) is widely used for modeling wave propagation and stiffness reconstruction in magnetic resonance elastography (MRE). However, it is not that efficient for modeling inclusions with complex interfaces. Here, we propose a formulation of FEM known as the eXtended FEM (XFEM), and investigate this method in two studies: wave propagation across an oblique linear interface and stiffness reconstruction of a random-shape inclusion. XFEM results present good agreement with the theoretical predictions and FEM simulation results. XFEM can be regarded as an ideal alternative to FEM for inclusion modeling in MRE.
Shear stiffness measured by MR elastography correlates with compression modulus in ex vivo rat livers subjected to increasing portal pressure.
Authors: Safraou Yasmine , Graczynska Karolina , Meyer Tom , Tzschätzsch Heiko , Fischer Thomas , Braun Jürgen , Sack Ingolf , Guo Jing
Published: August 2023

To investigate the effect of perfusion pressure on liver stiffness, 13 ex-vivo rat livers were studied by volumetric MRI, MR elastography (MRE) and diffusion MRI under controlled portal pressures between 0 and 15 cmH2O. Liver volume, tissue-vascular volume fraction, stiffness and bulk modulus decreased while water diffusivity increased with increasing portal pressure. Collectively, our findings suggest that liver softening is caused by a relative increase in fluid volume while an increased vascular pressure, potentially increasing liver stiffness, is of minor importance when tissue can freely expand, as in our scenario.
Investigating the Repeatability of Multifrequency Magnetic Resonance Elastography applied to a Soft Gelatin Phantom
Authors: Siddiqi Owais , Winfield Jessica , Zormpas-Petridis Konstantinos , Harris Emma , Ramkumar Anand , Candito Antonio , Görner Steffen , Messiou Christina , Blackledge Matthew , Thrussell Imogen
Published: August 2023

New measures of response are required that can capture the inherent heterogeneity and the heterogeneous changes observed in soft tissue tumours. Shear-wave Magnetic Resonance Elastography (MRE) measures stiffness of tissue by measuring the propagation of externally applied shear waves. In this study we explore the test-retest repeatability of Multifrequency MRE (MMRE), acquired using an echo-planar imaging readout applied to a soft gelatin phantom used to mimic the stiffness of soft-tissue tumours. Our results suggest MMRE is highly repeatable and supports further investigation in using MMRE to measure response in soft-tissue tumours.
MR Elastography of short T2 samples with Optimal Control-based RF pulses demonstrated on Achilles tendon
Authors: Sango-Solanas Pilar , Tse-Ve-Koon Kevin , Van Reeth Eric , Caussy Cyrielle , Beuf Olivier
Published: August 2023

Magnetic Resonance Elastography (MRE) allows the quantitative characterization of mechanical properties of tissues based on the properties of shear wave propagation. MRE uses mostly oscillating motion encoding gradients (MEGs) to encode motion. Their presence involves long echo times, limiting the application of MEGs to very short T2 tissues. RF pulses designed with an optimal control (OC) algorithm applied with a constant gradient can simultaneously perform slice selection and motion encoding, enabling short echo times. In this study, we used OC pulses to mechanically quantify by MRI for the first time a very short T2 tissue such as the Achilles tendon.
Quantitative server-based analysis of MR elastography inversion methods on a phantom and the in vivo human kidney
Authors: Meyer Tom , Garcia Stephan Marticorena , Tzschätzsch Heiko , Herthum Helge , Shahryari Mehrgan , Braun Jürgen , Kalra Prateek , Kolipaka Arunark , Sack Ingolf
Published: August 2023

Magnetic resonance elastography (MRE) depicts the viscoelastic properties of soft tissues for diagnosis of various diseases such as tumors or fibrosis. However, different MRE inversion methods yield different results. This lack of comparability of different MRE inversion results hinders the dissemination of advanced reconstruction methods. Therefore, we here introduce an extensible, open-access web platform that offers multiple inversion techniques for multifrequency, three-dimensional MRE to promote comparison of values. We demonstrate the utility of the platform in phantom data and in vivo free-breathing multifrequency MRE data of the kidneys of healthy volunteers.
Initial Study on Imaging Cyclic Tissue Motion with Motion Encoding Gradients in the Shape of Wavelet Basic Functions
Authors: Le Yuan , Chen Jun , Rossman Phillip , Bolster Bradley , Kannengiesser Stephan , Ehman Richard
Published: August 2023

The goal of this study was to better detect cyclic motion with multiple frequencies in tissue. A novel MRE technique was developed using motion encoding gradient (MEG) pulses of multiple scales (multi-scale MRE). These MEG pulses were designed and timed to approximate a complete basis of Haar wavelet system. Our hypothesis was that a set of orthogonal MEG pulses can capture the tissue motion more efficiently and tissue motion can be reconstructed by a simple inverse transform. Initial tests were performed on a phantom and a volunteer.
Impact of bowel preparation methods on pancreatic Magnetic Resonance Elastography
Authors: van Schelt Anne-Sophie , Wassenaar Nienke , Schrauben Eric , Nelissen Jules , Guo Jing , Sack Ingolf , Stoker Jaap , Nederveen Aart , Runge Jurgen
Published: August 2023

Pancreas magnetic resonance elastography (MRE) allows non-invasice estimation of tissue stiffness for multiple pathophysiological diseases. MRE reproducibility and the effect of bowel-preparation (butylscopolaminebromide and drinking water) for increased MRE data quality were assessed for the pancreas. Shear wave speed and MRE quality were determined for the pancreas, liver and kidneys. Intrasession and intersession reproducibility showed a coefficient-of-variation of 6.59% and 13.10%. Repeated measures ANOVA showed no significant difference in SWS of all organs (f=3/11,p>0.05). Bowel-preparation methods for pancreatic MRE do not increase MRE quality. Drinking water increases the MRE quality for kidneys and liver whilst not altering the measured SWS.
Brain stiffness correlates with hematocrit
Authors: Seja Jakob , Kreft Bernhard , Herthum Helge , Shahryari Mehrgan , Braun Jürgen , Sack Ingolf , Hetzer Stefan
Published: August 2023

The viscosity of blood scales with the concentration of red blood cells (hematocrit) and potentially influences the viscoelasticity of the perfused tissue. In this study, cerebral MR elastography (MRE) was applied to a group of healthy subjects to analyze the interrelation between mechanical properties of brain tissue and the hematocrit. We found a highly significant positive correlation between in-vivo mechanical properties of cerebral tissue and hematocrit level (p<0.0001).
Combination of screen printed process with electrodeposition steps to drastically improve flexible MRI coils sensitivity
Authors: Sousa Camila , Gnanago Jean-Lynce , Gilmus Valernst , Gerges Tony , Lombard Philippe , Cabrera Michel , Dorez Hugo , Lambert Simon
Published: August 2023

In the last few years, there has been an increasing interest from the scientific community in the fabrication of flexible coils. Several methods can be used for the manufacture of flexible coil, mainly screen-printed coils on flexible substrates. In this work, three different screen printing coils with different layers of silver ink were manufactured and their quality factors were measured on bench. A MR-coil combining screen-printed process with electrodeposition step was also built. The additional manufacture step allowed improving drastically Q factor of our screen-printed coil with more than one order of magnitude while maintaining good flexibility of the substrate.
Thalamic volume and lateralization on Parkinson Disease associated with cognitive and motor deficits
Authors: Ferrer-Gallardo Vicente , Esteban-Peñalba Teresa , Caballero-Gaudes César , Paz-Alonso Pedro M
Published: August 2023

This study sheds light on the relationship between the thalamic nuclei volume and their lateralization with cognitive and motor scores in PD. Two partial least squares analyses were performed between the volume or laterality indexes of all nuclei and clinical and cognitive scores. Cognitive deficits in semantic fluency and symbols and digits tests in PD are related to ventral, central and medial thalamic nuclei rather than to specific nuclei differences, except for the right-AV. Motor deterioration seems to be reflected in specific lateralization of the medial and pulvinar areas.
7T resting state connectivity applied to HIFU procedures for planning and efficacy
Authors: Lowe Mark , Lin Jian , Nemani Ajay , Nagel Sean , Jones Stephen
Published: August 2023

High Intensity Focused Ultrasound (HIFU) in now entering clinical practice, for example to treat essential tremor by causing small lesions in the thalamus. Due to small size of treatment lesions, treatment success depends critically on targeting, which is classically done using measurements and landmarks. We explore an alternative method using functional imaging to guide targeting, specifically using 7T resting state connectivity. We present preliminary data of the patterns of connectivity possible with 7T using a concatenated series of 18 healthy subjects.
Improved 7T High-Resolution Human Hippocampal Imaging with Multi-Frequency Magnetization Transfer (MFMT)
Authors: Beyers Ronald , Denney Thomas
Published: August 2023

Alzheimer’s disease (AD) and other cognitive debilitating disease drive the need to improve neuro 7T MRI methods. We developed a multi-frequency magnetization transfer (MFMT) method for contrast improvement in 7T 3D MRI of the human hippocampus. MFMT applied to healthy volunteers demonstrated a 2.05 (p < 0.003) factor improvement in hippocampal contrast.
REPRODUCIBILITY OF 7T MEASUREMENTS OF THE SUSCEPTIBILITY AND VOLUME OF HIPPOCAMPAL SUBFIELDS
Authors: Adeyemi Oluwatobi , Mougin Olivier , Gowland Penny , Bowtell Richard , Hosseini Akram
Published: August 2023

This study provides an assessment of the level of reproducibility of measurements of the magnetic susceptibility of the hippocampal sub-fields that can achieved at 7T in a group of healthy volunteers using high-resolution QSM in conjunction with ASHS segmentation. The 2 to 4 ppb range of the values of the average standard deviation of repeated measurements characterises the minimum level of susceptibility change that could be reliably assessed in longitudinal studies, such as those evaluating changes in the iron content of the hippocampal sub-fields in Alzheimer’s disease.
Advanced reconstruction provides improved image quality and enables shorter breath-holds in contrast-enhanced liver imaging
Authors: Stockton David , Rata Mihaela , Castagnoli Francesca , Shur Joshua , Hopkinson Georgina , Macdonald Alison , Nickel Marcel , Kannengiesser Stephan , Koh Dow-Mu , Winfield Jessica
Published: August 2023

An advanced reconstruction method, which employs a neural network trained on high resolution data to conduct interpolation, combined with iterative denoising, was applied in contrast-enhanced liver imaging in patients receiving a hepatocyte-specific contrast agent. The advanced reconstruction provides improved image quality, with better contrast-to-noise ratio, vessel edge sharpness, and lesion edge sharpness compared with the standard reconstruction using zero-filling interpolation without advanced reconstruction. The improvement in image quality was also observed in faster acquisitions (lower phase resolution), thus enabling shorter breath-hold acquisitions.
Test-retest reliability of in-vivo 31P MRSI of the whole human liver at 7 Tesla using a 31P whole-body transmit coil and 16-channel receive array
Authors: van den Wildenberg Lieke , Gursan Ayhan , Seelen Leonard , van der Velden Tijl , Gosselink Mark , Froeling Martijn , van der Kemp Wybe , Klomp Dennis , Prompers Jeanine
Published: August 2023

Alterations in 31P metabolite concentrations in the liver can be a consequence of liver disease and therefore 3D 31P MRSI can help in diagnosis and following progression and treatment response. However, commonly used 31P surface coils have a limited penetration depth and do not provide full coverage of the liver. We used an integrated 31P whole-body transmit coil with a local 31P receive array for 31P MRSI of the liver at a 7T MRI scanner. Here we demonstrate that 31P signals can be measured throughout the liver and 31P metabolite levels can be quantified with good to excellent test-retest reliability.
Simultaneous Assessment of Complementary Metabolic Pathways in Liver Using Co-polarized Hyperpolarized 13C pyruvate and 13C dihydroxyacetone
Authors: Kim Yaewon , von Morze Cornelius , Gordon Jeremy , Larson Peder , Ohliger Michael
Published: August 2023

Hyperpolarized 13C MRS is a powerful emerging technique for assessing metabolic liver diseases, including diabetes and fatty liver. Chemical shift separation allows monitoring of many metabolites at once. Here, we explore the possibility of co-polarizing [1-13C]pyruvate and [2-13C]dihydroxyacetone to simultaneously assess two important metabolic pathways that are altered in liver disease. Co-polarization was successful, with preserved T1 relaxation times. Although co-polarization led to modest decreases in polarization levels, all expected metabolites were observed when injected into a healthy rat. By examining two pathways at the same time, co-polarization can be an important tool for assessing liver disease.
Early Quantitative Diagnosis of Articular Cartilage Degeneration Using 3D Ultrashort Echo Time Cones Adiabatic T1ρ ( UTE Cones AdiabT1ρ) Imaging
Authors: Wu Mei , Ma Ya-jun , Wu Zhouchonghao , Xue Yanping , Zheng Yanting , Wei Zhao , Jerban Saeed , Jang Hyungseok , Chang Douglas , Ma Liheng , Chang Eric , Du Jiang
Published: August 2023

This study aims to evaluate cartilage degeneration using 3D UTE-Cones-AdiabT1r imaging at 3T. In total 66 human subjects were recruited. KL and WORMS were evaluated by two MSK radiologists. The performance in evaluating cartilage degeneration was assessed via Spearman’s correlation coefficient and the area under the curve (AUC) calculated according to the receiver-operating characteristic (ROC) curve. Higher UTE-Cones-AdiabT1r values were observed in larger and deeper cartilage lesions. The diagnostic threshold of UTE-Cones-AdiabT1r for mild cartilage degeneration was 39.4 ms with 80.8% sensitivity and 63.5% specificity. The AUC value for mild cartilage degeneration (WORMS=1) was 0.8 according to the ROC curves.
Topographical Associations of Knee Cartilage MRI with Osteoarthritis Pain: Data from the Osteoarthritis Initiative.
Authors: Peake Edward , Turmezei Tom , Auer Dorothee
Published: August 2023

Pain is a hallmark of knee osteoarthritis, a chronic condition with considerable health and socioeconomic burden. Osteoarthritic changes of the knee cartilage are often used as an outcome marker for clinical trials, but only weakly associated with pain. In this study, we aimed to examine the topographic correlation between intensity differences in knee cartilage MRI and knee pain. Voxel based morphometry (VBM) is used with linear effects modelling to show the spatial localization of knee OA contributing to pain. Local maxima and clusters with extents with P<0.05 are determined using random field theory.
3-D T1 relaxation time measurements in an equine model of mild post-traumatic osteoarthritis using MB-SWIFT
Authors: Pala Swetha , Nykänen Olli , Hänninen Nina , Mohammadi Ali , Ebrahimi Mohammadhossein , Moller Nikae te , Brommer Harold , van Weeren P René , Mäkelä Janne , Korhonen Rami , Töyräs Juha , Mikkonen Santtu , Nissi Mikko
Published: August 2023

In this study, we examined the variation in T1 relaxation times in a mild OA model of surgically grooved (sharp and blunt) articular cartilage of equine carpal joints. The study revealed that T1 relaxation time is significantly increased in bluntly-grooved cartilage with respect to control cartilage. No significant differences between sharply-grooved and control groups were seen for T1 relaxation. Moreover, strong variations in T1 relaxation times and proteoglycan (PG) contents were observed in the superficial half of the cartilage. T1 relaxation times correlated weakly (R≈0.33) with equilibrium mechanical modulus and with PG content (R≈0.23).
Optimized U-net++: Novel Algorithm for Sub-regional Segmentation of Knee Cartilage and Bone
Authors: Zhong Lijie , Hu Jiaping , Chen Shaolong , Chen Yanjun , Zhang Zhongping , Mei Yingjie , Zhang Zhiyong , Zhang Xiaodong
Published: August 2023

Cartilage degeneration and subchondral bone alterations play an important role in the pathogenesis and progression of knee osteoarthritis (OA). MRI can detect morphological or compositional change of cartilage and bone. Regional analysis of cartilage and bone lesions would significantly improve the diagnosis of OA and help to understand its role in OA. Automated segmentation of cartilage and bone on MRI is a necessary first step for quantitative measures. Therefore, we proposed an optimized U-net (PSA-U-net++) to solve the problem of sub-regional segmentation of bone and cartilage. The initiatory results showed that our model can accurately segment cartilage and bone.
RF Energy Harvesting System for Autonomous Respiratory Sensor in MRI
Authors: BENAMARA Megdouda , Bakkali Asma , Gomez tania-del-socorro Vergara , Raynard Camille , Vilmen Christophe , Jomin Pierre , Trabelsi Amira , Berrahou Djamel , Dubois Marc , Le Fur Yann , Kober Frank , Bendahan David , Bergeret Emmanuel , Egels Matthieu , Enoch Stefan , Abdeddaim Redha
Published: August 2023

The energy harvesting system was developed for preclinical 4.7 T MRI scanners. The system is composed of a commercial birdcage coil tuned and matched at 200.1 MHz, a harvesting coil and an RF-DC rectifier. The collected energy was used to power a respiratory pressure sensor. The efficiency of the harvesting system was optimized as function of the angular positioning of the harvesting coil in the birdcage. The experiments were carried out with a water phantom and a mouse in vivo. A peak voltage of 1.5V was harvested for 45V input voltage and delivered to a load of 350 Ω.
Preclinical MR spectroscopy of GABA: conventional PRESS versus spectral editing with MEGAPRESS and HERMES
Authors: Rotaru Diana , Sawiak Steve , Simmons Camilla , Kim Eugene , Navacerrada Maria Elisa Serrano , Di Censo Davide , Le Guennec Adrien , Edden Richard , Lythgoe David , Cash Diana
Published: August 2023

In vivo GABA measurements with conventional (PRESS) and spectral editing methods (MEGAPRESS and HERMES) were investigated in healthy mice at 9.4 T. Animals were divided in two groups, control mice injected with saline and mice injected with Aminooxyacetic acid to intentionally elevate GABA concentration levels (n=7 per group). Our results show all three methods successfully discriminate GABA from overlapping metabolites with stronger signals. The precision of concentration estimates is more reliable for spectral editing methods given their specificity to GABA. These outcomes suggest spectral editing methods are less susceptible to systematic biases.
Inhibition of GSK3 Activity Detected by Glycogen Synthase Activity from Proton MRS at 3T
Authors: Brender Jeff , Kishimoto Shun , Munasinghe Jeeva , Merkle Helmutt , Yamashita Kota , Otowa Yasunori , Yamamoto Kazutoshi , Krishna Murali
Published: August 2023

Glycogen synthase kinase 3 (GSK3) has been tied as a critical factor in the development of multiple major diseases from cancer to Alzheimer’s, but drug development has been stymied by a lack of options to detect GSK3 activity in vivo. We show here that GSK3 activity can be measured accurately in vivo by following the production of glycogen from a single bolus of unlabeled glucose on a standard 3T preclinical imaging system. Imaging of glycogen synthesis was possible at 9.4T by CSI, where it was found in mice to be centered on the olfactory bulb, as expected from post-mortem analysis
Quantitative MR Imaging of Whole Intervertebral Disc: A Pre-Clinical Sample Study
Authors: Athertya Jiyo , Lombardi Alecio , Wong Jonathan , Jang Hyungseok , Jerban Saeed , Du Jiang , Masuda Koichi , Chang Eric , Ma Ya-Jun
Published: August 2023

Quantitative MR imaging is a powerful tool for assessing biochemical changes in tissue. In this study, we propose to measure the transverse magnetization relaxation time, diffusivity, and magnetization transfer ratio for a whole intervertebral disc (IVD), including the annulus fibrosis, cartilaginous endplate (CEP), and nucleus pulposus, on a 3T pre-clinical scanner. The sequence parameters were optimized for high resolution and high signal-to-noise ratio imaging and mapping, utilizing the high-performance gradient system on the pre-clinical scanner, and the echo times were sufficiently minimized to capture the fast-decaying CEP signals for all the quantitative imaging sequences.
Iterative Model-Based Image Reconstruction of RF gradient-based MRI
Authors: Froelich Taylor , Garwood Michael
Published: August 2023

When reconstructing with traditional Fourier-based techniques, image distortions arising from nonlinear B1 and B0 inhomogeneity can plague radiofrequency-based (RF) imaging methods that rely on B1 gradients for spatial encoding. In this work, we propose a new framework for reconstructing multi-dimensional RF gradient-based images leveraging an iterative approach to solve a regularized inverse problem. The proposed methodology employs a full Bloch simulation to reconstruct an undistorted image after determination of the forward operator and measured receive coil sensitivities.
Low Latency Real-Time MRI at 0.55T using Self-Calibrating Through-Time GRAPPA
Authors: Kumar Prakash , Lim Yongwan , Nayak Krishna
Published: August 2023

Real-time MRI (RT-MRI) captures movements and dynamic processes in the human body as they occur, without reliance on any repetition or synchronization. Many applications of RT-MRI require low-latency reconstruction for feedback or interventions (typically <200ms). Here, we investigate self-calibrating spiral Through-Time GRAPPA at 0.55T and compare its performance against viewsharing and constrained reconstruction methods. We use longer readouts, which can be used at low-field due to reduced off-resonance effects. We demonstrate RT-MRI of speech production with 13.09ms temporal resolution and 25ms reconstruction latency (after a 30s pre-computed calibration step).
Comparison of distortion correction with Echo Planar Imaging Correction and the 2D navigator based multi-shot SENSE EPI schemes
Authors: Zhang Yajing , Wu Zhigang , Hu Xiuquan , Jiang Guangyu , Zhang Jing , Zhao Yan , Van Cauteren Marc , Wang Jiazheng
Published: August 2023

Brain diffusion imaging by single shot EPI has remained challenging for the local B0 field variation, which leads to geometry distortion and signal inhomogeneity in the resulting images. In this study, we show that the brain single shot EPI image quality could be improved by correction of the geometric distortion and increased resolution, when compared to the traditional acquisition scheme. In-plane resolution of 1.2x1.2 mm2 was achieved and the distortion correction was effectively reduced.
Application of susceptibility source separation (chi-separation) to UK Biobank protocol and clinical protocol using deep neural network
Authors: Jeong Hwihun , Oh Sung Suk , Lee Jongho , Shin Hyeong-Geol
Published: August 2023

We develop pipelines for reconstructing susceptibility source separation (χ-separation) maps, which requires a T2 map, from UK Biobank protocol and routine clinical protocol data that have no T2 map but have various T2-weighted contrasts (e.g., FLAIR and T2-weighted images). Using these and additional contrast-weighted images, we propose a deep neural network framework that generates an R2 (=1/T2) map, with which χ-separation is conducted. The proposed pipelines successfully generated positive and negative susceptibility maps that are highly similar to gold standard results. The results suggest that χ-separation is applicable to various clinical routine protocols and open-source data.
Realistic brain phantom for Susceptibility Tensor Imaging
Authors: Munoz Nestor , Milovic Carlos , Tejos Cristian
Published: August 2023

Susceptibility tensor imaging (STI) is a recent MRI technique that is able to quantify anisotropic magnetic susceptibilities in the human tissues. It needs at least 6 acquisitions with different rotation angles to robustly reconstruct each component of a second order tensor. Several methods have been proposed to reconstruct STI, including least squares methods or optimization algorithms. Since there is not a ground truth, it is difficult to evaluate the effectiveness of these algorithms. In this study, we propose a realistic brain human phantom to evaluate and compare different STI reconstruction algorithms.
Brain Health in Preterm Infants: Cerebral Metabolic Rate of Oxygen (CMRO2) Using Advanced MRI
Authors: Zhu Chen Shuang , Weber Alexander , Grunau Ruth , Chan Natalie
Published: August 2023

Cerebral metabolic rate of oxygen (CMRO2) is a measurement of oxygen metabolism that may help determine outcomes in preterm neonates and improve treatments. However, limitations exist in current methods for measuring CMRO2. Advanced MRI techniques such as quantitative susceptibility mapping (QSM) may be able to overcome these challenges. GE 3T MRI data of preterm neonates at term equivalent age (TEA) (n=9) was obtained and analyzed using a standard equation to determine the CMRO2. CMRO2 values agreed with literature values and correlated strongly with birth age, but not with birth weight or head circumference at birth.
Clinically uncertain parkinsonism shows nigral depigmentation in the presence and absence of dopaminergic deficit: a multimodal imaging study
Authors: XING YUE , Naidu Saadnah , Gennaro Marta , Antonios-Roussakis Andreas , Lao-Kaim Nicholas , Abdul-Sapuan Halim , Evans Jonathan , Sare Gillian , Martin-Bastida Antonio , Stefan Schwarz , Piccini Paola , Auer Dorothee
Published: August 2023

Brain dopamine transporter (DAT) imaging with 123I-FP-CIT SPECT has been used for detecting striatal deficits in clinically uncertain parkinsonism (CUP). Neuromelanin(NM)-MRI assesses nigral depigmentation with high accuracy in confirmed PD; but its diagnostic value in CUP is unclear. Here, we compare nigral NM in CUP with (DAT+) or without (DAT-) striatal dopaminergic deficits, to established PD and healthy controls. CUP with DAT+ had more nigral NM deficits (vs. controls and DAT-CUP) but were less pronounced than in established PD. Interestingly, DAT- cases showed ventrolateral nigral deficits. Our results suggest that nigral depigmentation possibly starts before striatal dopaminergic decline.
Sensorimotor-Related Area Abnormalities in Amyotrophic Lateral Sclerosis: An Intravoxel Incoherent Motion Magnetic Resonance Imaging Study
Authors: Shi Jia , Chen Hua
Published: August 2023

We conducted the first assessment of the sensorimotor-related areas(SMA) alterations in ALS using IVIM MRI and atlas-based analysis, which may provide useful information for localization of specific cortex and white matter(WM) tract damage in ALS. In grey matter areas (GM), ALS patients showed a reduction in f in the bilateral preSMA and SMA, while in WM areas, ALS patients exhibited an increase in D in a WM tract projecting to the right ventral premotor cortex(PMv). Correlation analysis revealed that the average D in this right PMv tract was negatively correlated to ALS disease severity.
Application of Graph Theory in the study of functional and structural connectivity in Mild Cognitive Impairment (MCI) disease
Authors: Cipriano Emilio , Biagi Laura , Bosco Paolo , Cioni Giovanni , Sale Alessandro , Berardi Nicoletta , Matteoli Michela , Tosetti Michela , Consortium the Train the Brain
Published: August 2023

Graph theory approach was used to analyze structural and functional connectivity networks to identify candidate biomarkers of Mild Cognitive Impairment (MCI), a prodromal stage of Alzheimer’s disease (AD), for an early diagnosis and intervention. We proposed a method of brain network analysis to combine structural and functional connectivity networks information. Through graph measures (Segregation, Centrality and Global Efficiency), we evaluated the differences between MCI and healthy control (HC) subjects as well the possible effects of physical/cognitive training, in terms of structural and functional connectivity, in MCI population.
Automatic detection of the anterior choroidal artery in TOF-MRA and its trajectory through the hippocampus and its sub-regions
Authors: Janelle Félix , Sean Monica , Dumais Félix , Tétreault Pascal , Bocti Christian , Whittingstall Kevin
Published: August 2023

The Anterior Choroidal Artery (AChA) is a small artery in the cerebral vasculature that perfuses the hippocampus. Its role in brain pathologies and cognitive decline is poorly understood. This could be due to the fact that there is no current standard method to analyse this artery in Time-of-Flight Magnetic Resonance Angiography (TOF-MRA). Here, we propose a fully automated approach for accurately localizing and quantifying the AChA in young healthy subjects. We then used this method to analyse the trajectory of the AChA through the hippocampus and its sub-regions.
Reproducibility of MR Elastography Stiffness Measurements across Field Strength in Obese Adults
Authors: Panagiotopoulos Nikolaos , Batakis Danielle , Wolfson Tanya , Oechtering Thekla , Harris David , McMillan Alan , Sirlin Claude , Reeder Scott
Published: August 2023

MR elastography (MRE) allows for the quantification of liver stiffness as a quantitative biomarker of liver fibrosis. Between field strength reproducibility has been shown to be high in non-obese populations. Data in obese individuals are limited, however, and obese patients may benefit from early diagnosis as they have an increased risk of liver fibrosis. Therefore, in this work we examined the reproducibility of MRE measurements across field strength in a cohort of 34 obese adults. MRE based liver stiffness measurements were highly reproducible between field strengths. Technical success rate was nearly 100% in this challenging, but relevant population.
Relevance of diffusion time for DKI detection of liver pathology
Authors: Simoes Rui , Otake Andreia , Batista Silvia , Henriques Rafael , Costa-Silva Bruno , Shemesh Noam
Published: August 2023

Despite the recent interest in diffusion kurtosis imaging (DKI) for assessing liver pathologies, its added value over more standard diffusion-weighted or diffusion tensor imaging techniques remains to be established. Importantly, mean diffusivity (MD) and mean kurtosis (MK) estimations are strongly dependent on the diffusion time (DT), a parameter generally overlooked in liver DKI studies. Here, we demonstrate ex vivo the relevance of short DT – namely 10 ms rather than 40 ms – for MK detection of liver disease, using two well-described mouse models of liver metastasis and fibrosis.
MRI of the Post-Operative Hip Following Arthroscopic Repair: What are the Imaging Characteristics of Labrum Re-Tear and Capsular Complications?
Authors: Handley Douglas , Tang Joseph , Spiker Andrea , Blankenbaker Donna
Published: August 2023

After acetabular labrum repair an intact repair, labrum re-tear, adhesions, and capsular disruption can have variable appearance on MRI. Some signs have been described as evidence of labral re-tear and adhesions. We retrospectively evaluated 25 hip MRIs in patients who later underwent revision arthroscopy utilizing these signs. Results were compared to arthroscopic findings. Fluid signal within the labrum demonstrated a high specificity for re-tear. Signs of adhesion were often identified accurately but could be imitated by synovitis. Capsular disruption was also identified with high sensitivity.
Using MRI to Differentiate Synovial Reponses in Patients with Total Knee Arthroplasty
Authors: Koff Matthew , Padgett Elexis , Landy David , Sculco Peter , Sculco Thomas , Wright Timothy , Potter Hollis
Published: August 2023

Many patients are satisfied following total knee arthroplasty (TKA) surgery, but post-operative challenges occur. This study evaluated synovial reactions in patients with TKA and related pre-operative MRI findings to direct evaluation of retrieved tibial polyethylene liners from revision surgery. Patients with synovial response of 'arthrofibrosis' had less damage to the tibial insert than patients with a synovial response of 'polymeric'. MRI was able to distinguish specific synovial responses directly to clinically confirmed arthrofibrosis and aseptic loosening.