bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporating Histological Grading for Brain Tumor Segmentation
Authors: Zhang Lipei , We Yiran , Li Chao , Price Stephen , Schönlieb Carola
Published: August 2023

Automatic tumor segmentation on MRI is crucial for patient management of brain tumors. However, previous automatic MRI segmentation methods based on deep learning are limited by bottlenecks of feature extraction. In this paper, we seek to investigate the influence of incorporating prior histology grading on the performance of tumor segmentation. We propose to employ histological grade labels to strengthen the feature extraction and tumor localization in the encoder, which can boost the DSC at exceeding 2% in different U-Net baselines. Our results could support the usefulness of incorporating clinical prior knowledge to improve the segmentation performance without introducing extra parameters.
Protocol adaptive Stacked transfer learning (STL) U-NET with small dataset training for soft tissue segmentation in dynamic speech MRI
Authors: Erattakulangara Subin , Kelat Karthika , Lingala Sajan
Published: August 2023

We develop a protocol adaptive Stacked transfer learning (STL) U-NET for soft tissue segmentation in dynamic speech MRI. Our approach leverages knowledge from large open-source datasets, and only needs to be trained on small number of protocol specific images (of the order of 20 images). We demonstrate the utility of STL U-NET in efficiently segmenting soft-tissue articulators from three different protocols with different field strengths, vendors, acquisition, reconstruction. Using the DICE similarity metric, we demonstrate segmentation accuracies with our approach to be at the level of manual segmentation.
Towards MR-guided Hyperthermia at Low Field: a Proof-of-Concept Investigation
Authors: Fiorito Marco , Spreiter Mauro , Yushchenko Maksym , Sarracanie Mathieu , Salameh Najat
Published: August 2023

MR-guided hyperthermia at low magnetic field is challenging due to the inherently low SNR, which typically calls for multiple signal averages. Dedicated coils are crucial at this field regime, to maximise signal acquisition. In this study we built a custom RF coil which integrates a water-based heating system to reproduce hyperthermia conditions in hands. Using a fast T1-mapping sequence, we could successfully monitor the temperature variations generated in a phantom over 120min. A first in vivo employment in a volunteer’s hand at room temperature was also shown, achieving a spatial and temporal resolution compatible with hyperthermia requirements.
Effect of Dielectric Resonator (DR) Modes on RF-Magnetic Field
Authors: Poshtgol Parisa Lotfi , Gandjii Navid Pourramzan , Lanagan Michael , Furman Eugene , Soon Soo Han , Chen Xinlian , Soltani Saber , Zhu Xiao-Hong , Sica Christopher T. , Wiesner Hannes M , Chen Wei , Ugurbil kamil , Yang Qing X
Published: August 2023

Dielectric resonators with Ultra-High Dielectric Constant (uHDC) materials possess intrinsic resonance modes that have been used for RF transmission and reception. The resonance modes and conditions of the uHDC discs were studied through computer simulations. We compared the B1+ field and RX-sensitivity when employing cylindrical uHDC discs at both resonant and non-resonant conditions. We showed in this work, to achieve the best focusing effect into phantom, the design with uHDC material should operate around the first TE01δ mode and lower than the second mode TE01δ with the highest permittivity.
Evaluation of an Ultra High Dielectric Constant (uHDC) Package for Enhancement of a Knee Phased Array
Authors: Sica Christopher , Poshtgol Parisa , Rupprecht Sebastian , Yang Qing
Published: August 2023

Prior work has explored the use of dielectric materials to enhance imaging of the brain and spine with rectangular blocks. One area that has not been examined to date is knee imaging, where space constraints limit the use of blocks. In this work we evaluate the performance of an ultra-high dielectric constant (uHDC) curved plate (εr ~ 4500) for knee imaging in a clinical array at 3T. SNR gains of 9 to 71% percent were observed across the patella and patellar cartilage. Transmit efficiency increased up to 100% close to the material, with an increase in transmit inhomogeneity.
Metasurface-based pad for improving fetal imaging at 3T
Authors: Puchnin Viktor , Koreshin Evgeniy , Kalugina Anna , Efimtcev Aleksander , Mashchenko Irina , Brink Wyger , Shchelokova Alena
Published: August 2023

Radiofrequency magnetic field homogeneity improvement and SAR reduction are two essential tasks for fetal MRI at 3T. We demonstrate for the first time that the metasurface-based pad can effectively improve the transmit efficiency while reducing SAR within the entire fetus and fetus brain. The metasurface is assembled from the metal wires loaded with capacitors. Numerical studies of a pregnant woman voxel model in the 9th month covered with the proposed metasurface centered within fetus brain (body) showed 25% (28%) transmit efficiency improvement and up to 9% (2.8%) increased magnetic field homogeneity, while the whole-body SAR was reduced by 1.2 (1.6)-fold.
Laminar fMRI with MT-prepared multi-echo 3D FLASH
Authors: Pfaffenrot Viktor , Koopmans Peter
Published: August 2023

The GRE-BOLD contrast used in laminar fMRI suffers from suboptimal specificity due to extravascular effects around large veins. CBV-weighting offers improved specificity with signal changes being more confined to microvasculature. CBV-weighting can be achieved through saturation of gray matter signal with magnetization transfer. We use a multi-echo FLASH sequence at 7 Tesla, with and without MT preparation to investigate its feasibility at ultrahigh field. We analyze the TE dependence to determine when the BOLD T2’-effects start to dominate the MT-weighted signal changes. The MTprep profiles exhibit a stronger signal change in gray matter at short TEs and reduced extravascular effects.
CBV-sensitive layer-fMRI in the human auditory cortex at 7T: Challenges and capabilities
Authors: Faes Lonike , Gulban Omer , Poser Benedikt , De Martino Federico , Huber Renzo
Published: August 2023

Laminar-specific fMRI with CBV-sensitive VASO is valuable for neuroscientific questions on hierarchical information processing. While VASO fMRI has already proven its utility in other brain areas, it has not yet been successfully applied in the auditory cortex due to several additional technical challenges in this region. Here, we explore multiple sequences and their effectiveness to mitigate these challenges. Our purpose is to develop an experimental setup that future neuroscientific studies can be built on. Ultimately, we found a stable parameter set for the usage of layer-fMRI VASO in the auditory cortex and validated it in a group of participants.
Prospective motion correction in multi-echo line-scanning fMRI at 7T: sequence implementation and strategies for functional data analysis
Authors: Raimondo Luisa , Priovoulos Nikos , Heij Jurjen , Knapen Tomas , Dumoulin Serge , Siero Jeroen , van der Zwaag Wietske
Published: August 2023

We implemented prospective motion-correction (PMC) for line-scanning fMRI. In line-scanning, online motion correction is needed since 1-dimensional data do not allow motion detection in every dimension and the limited coverage makes this approach sensitive to spin-history artifacts or scanning outside the area of interest, in the presence of motion. We compared three versions of PMC and three ways of managing the T1-driven return to equilibrium (T1-transient) introduced by the navigators, in the functional data analysis. We opted for a water-excitation navigator as the best alternative, and showed that the T1-transient can be successfully overcome in the functional analysis.
Thalamic and cortical input layers in the somatomotor cortex detected by laminar fMRI in non-human primates at 7T
Authors: Kang Sangyun , Han Min-Jun , Kim Seong-Gi , Baeg Eunha
Published: August 2023

Laminar fMRI has been increasingly used in humans, but its validity needs to be thoroughly confirmed in primate brains. Here, we investigated thalamic and cortical inputs to the somatomotor cortex in the rhesus monkey by adopting tactile stimulation and electrical microstimulation. Compared to 7T BOLD signals, MION-induced CBV-weighted fMRI faithfully captures input layer activities, like the sensory thalamus input to the middle layer and the dense cortical connections in the superficial layers. Taken together, our CBV-weighted fMRI signals revealed different input layers to the somatomotor cortex with high specificity and sensitivity.
Single-shot 3T 1H MRS with dual water/lipid VAPOR suppression for intrahepatic acetylcarnitine detection
Authors: Buitinga Mijke , Mevenkamp Julian , Haans Florian , Brouwers Kim , Schrauwen Patrick , Lindeboom Lucas , Wildberger Joachim , Schrauwen-Hinderling Vera
Published: August 2023

We have developed a novel 3T 1H-MRS sequence to detect acetylcarnitine. Acetylcarnitine has been investigated by 1H-MRS in the muscle and is thought to play an important role in maintaining metabolic flexibility and insulin sensitivity. As these are hallmarks of metabolic disease, techniques to study acetylcarnitine levels non-invasively are of great interest. The advantage of our approach is the absence of a subtraction scheme and high signal intensity, while both water and lipid resonances are sufficiently suppressed to uncover the acetylcarnitine resonance. This makes our sequence suitable also for detection in tissues susceptible to respiratory motion, such as the liver.
Integration of T2* mapping in daily prostate MR-Linac workflow for hypoxia characterisation
Authors: Bano Wajiha , Sritharan Kobika , Oelfke Uwe , Tree Alison , Wetscherek Andreas
Published: August 2023

T2* mapping can be a potential biomarker to characterise hypoxia and monitor treatment response throughout the course of MR-guided radiotherapy on an MR-Linac. This study explores the feasibility of integrating T2* mapping in daily prostate MR-Linac workflow using a cohort of patients with prostate cancer. We compared mean T2* values within the prostate with repeated measures acquired twice weekly during radiotherapy. T2* values at the end of treatment were higher than at the first fraction but didn’t show a consistent trend throughout treatment. Integrating T2* mapping with other functional measurements can aid in response based treatment adaptation.
MR Protocol Optimization for Treatment Planning Simulation of Ocular Melanoma Proton Therapy
Authors: Goette Matthew , Slopsema Roelf , Dhabaan Anees , Shu Hui-Kuo
Published: August 2023

An MR treatment planning simulation protocol for proton therapy in patients with ocular melanoma was optimized using a 70-mm loop coil.
A Framework for Brain Tumor Detection, Classification and Segmentation using Deep Learning
Authors: Ahsan Rafia , Shahzadi Iram , Aslam Ibtisam , Omer Hammad
Published: August 2023

Detection, classification and segmentation of brain tumor simultaneously is challenging due to the heterogeneous nature of the tumor. Limited work has been done in literature in this regard. The present study, therefore, aims to identify an object detection network that would be able to solve multi-class brain tumor classification and detection problem with high accuracy. Furthermore, the best performing detection network has been cascaded with 2D U-Net for pixel level segmentation. The proposed method not only classifies the tumor with high accuracy but also provides improved segmentation results compared to the standard U-Net.
Deep learning-based tumor segmentation from postoperative MRI
Authors: Li Jingpeng , Vardal Jonas , Groote Inge , Bjornerud Atle
Published: August 2023

To accurately detect and localize postoperative tumor after surgery is of critical importance to postoperative patient management and survial rate. We propose a fully automated end-to-end coarse-to-fine segmentation approach for the segmentation of posoperative tumor.
Deep learning-based segmentation of the parasagittal dural space from non-contrast anatomical MRI image: a resource for glymphatic studies
Authors: Hett Kilian , McKnight Colin , Eisma Jarrod , Elenberger Jason , Considine Ciaran , Claassen Daniel , Donahue Manus
Published: August 2023

The overarching goal of this work is to develop and validate novel deep learning algorithms for segmenting the parasagittal dural (PSD) space, which has been hypothesized to harbor cerebral lymphatic channels, from standard non-contrast anatomical imaging. Specifically, contrasted based MRI studies have recently suggested that the PSD may be important for CSF clearance, however existing methods for evaluating this space require administration of exogenous contrast and time-consuming manual tracing, thereby limiting generalizability. We propose a new segmentation method using non-contrasted MRI, and we validate this method in a mixed cohort of older adults with and without neurodegeneration.
Split-and-Merge Segmentation in Magnetic Resonance Imaging Based on Graph Wedgelets
Authors: Erb Wolfgang
Published: August 2023

Graph wedgelets are a novel tool for the fast decomposition of images in geometrically meaningful, wedge-shaped subregions. In this work, we study the usage of graph wedgelets as a promising splitting method in a split-and-merge segmentation scheme for Magnetic Resonance Imaging. We combine adaptive wedgelet splits of MRI images with a simple and classical merging strategy for subregions and obtain in this way an efficient and robust segmentation of diagnostic-relevant subdomains in MRI data.
Cascaded parallel imaging for 3D deep learning reconstruction
Authors: Lyu Jingyuan , Ye Yongquan , Zhang Zhongqi , Xu Jian , Chen Xiao , Chen Terrence , Sun Shanhui , Chen Eric Z.
Published: August 2023

This study demonstrates the effects on image reconstruction by integrating a separate parallel imaging layer with the deep learning module. With such additional layer, deep learning reconstruction is flexible and reliable for highly under-sampled data.
Breathing task paradigm to improve the quality of pancreatic Magnetic Resonance Elastography
Authors: Wassenaar Nienke , van Schelt Anne-Sophie , Schrauben Eric , van der Woude Rémi , de Jong Jamila , Nelissen Jules , van Laarhoven Hanneke , Guo Jing , Sack Ingolf , Runge Jurgen , Nederveen Aart , Stoker Jaap
Published: August 2023

Free-breathing acquisition of pancreatic MR elastography can potentially introduce errors in stiffness reconstruction. In this study, breathing tasks are introduced during interleaved and reversed slice order MRE acquisition to determine if the quality of MRE increases. The shear-wave speed and octahedral shear strain signal-to-noise-ratio in the pancreas did not significantly change when using breathing tasks. However, the stability of the pancreas location over time increases when using breathing tasks combined with reversed slice ordering as well as the octahedral shear strain signal-to-noise-ratio in the whole abdomen. Future research should focus on comparing shear-wave speed reproducibility of both MRE methods.
2D or 3D MR elastography of the brain? Answers from a 1-year follow-up study in healthy volunteers.
Authors: Herthum Helge , Tzschätzsch Heiko , Shahryari Mehrgan , Kreft Bernhard , Görner Steffen , Hetzer Stefan , Braun Jürgen , Sack Ingolf
Published: August 2023

MR elastography(MRE) measures in vivo soft-tissue mechanical parameters which are sensitive to various diseases. Robust and reliable measurements are critical for clinical translation; however, the variability of reported values, especially for MRE in the brain, remains a challenge. We here introduce an optimized setup for high-resolution brain MRE and compare the consistency of values obtained from 2D- and 3D-analysis in a group of healthy subjects studied in the follow-up of a year. Both 2D- and 3D-MRE values agreed very well between the two measurements. Intersubject variability was lower in 2D than in 3D while intrasubject variability was lower in 3D.
Feasibility evaluation of virtual elastography based on diffusion-weighted imaging (vMRE) at 1.5 Tesla
Authors: Garcia Alicia Palomar , Prevost Valentin , Sanchez Alba Iruela , de Graaf Wolter , Triaire Bruno
Published: August 2023

This study evaluated the feasibility of performing virtual elastography based on diffusion-weighted MRI (vMRE) on a 1.5T system with two different acceleration methods, SPEEDER and EXSPER. Proton density fat fraction (PDFF) imaging was also acquired. The vMRE and PDFF measurements were consistent with healthy values that can be found in the literature. This study demonstrated the feasibility of performing vMRE at 1.5T for the estimation of overall liver elasticity. SPEEDER and EXSPER vMRE implementations provided consistent stiffness estimations and both would be adequate for conducting future studies at 1.5T systems on patients.
Improving the Flexibility of RF Power-Sharing Networks with High-Power Phase Shifters
Authors: Ogier Stephen , Malik Shaihan , Hajnal Joseph
Published: August 2023

A typical parallel transmit system has an equal number of RF power amplifiers individually connected to an equal number of coil elements. When performing B1+ shimming, the maximum B1+ available is limited by single channel amplifier performance. RF networks which allow for power to be shared between transmit channels have been proposed as a way to overcome this limitation, but fixed networks only offer performance gains over limited ranges of relative phases between channels. Adding a high-power phase shifter between a power-sharing network and coil element can combat this, even with only a few bits of resolution.
Assessment of white matter changes associated with neurodegeneration in Alzheimer’s disease and early Parkinson’s disease
Authors: Bergamino Maurizio , Aslam Sana , Shill Holly , Stokes Ashley
Published: August 2023

The objective of this study was to assess white matter integrity in both Alzheimer’s disease (AD) and early Parkinson’s disease (PD) using diffusion tensor imaging (DTI) metrics and connectivity analysis. Single-shell DTI data were obtained from open-source databases for AD and PD.
Fine-grained characterisation of white matter microstructural abnormality in the pathophysiological cascade of Alzheimer’s disease
Authors: Parker Christopher , Zhang Hui , Oxtoby Neil
Published: August 2023

White matter (WM) microstructure abnormalities have been observed in prodromal and manifest Alzheimer’s disease (AD). However, the precise nature and sequence of WM neurodegeneration across the disease course is unclear. Here, we leverage state-of-the-art disease progression modelling to sequence WM microstructure abnormalities in AD, as quantified by diffusion MRI in the ADNI study. We observe WM abnormalities among the earliest AD structural abnormalities and characterise the precise sequence of WM neurodegeneration. This fine-grained approach may be used to identify subjects at early disease stages for participation in therapeutic clinical trials.
Longitudinal Assessment of Intravoxel Incoherent Motion Diffusion-Weighted MRI (IVIM-DWI) Metrics in Alzheimer’s Disease
Authors: Bergamino Maurizio , Steffes Lori , Burke Anna , Baxter Leslie , Caselli Richard , Sabbagh Marwan , Stokes Ashley
Published: August 2023

The objective of this pilot study was to assess the complementary brain microstructural and perfusion changes using the apparent diffusion coefficient (ADC) and the intravoxel incoherent motion-diffusion weighted imaging (IVIM-DWI) parameters in a group of cognitively impaired people over a period of 12 months. Additionally, voxel-based correlations between cognitive assessment scores and DWI imaging parameters were evaluated.
Confidence Maps for Reliable Proton Density Fat-Fraction Estimation in the Presence of Low SNR
Authors: Weaver Jayse , Roberts Nathan , Hernando Diego , Reeder Scott
Published: August 2023

Chemical-shift-encoded MRI (CSE-MRI) is an established technique to estimate proton density fat-fraction (PDFF) as a quantitative imaging biomarker of hepatic steatosis. However, due in part to low flip angle acquisitions, CSE-MRI acquisitions often have low SNR leading to biased and noisy PDFF measurements. Unreliable PDFF measurements are particularly problematic considering clinically relevant PDFF thresholds may be as low as 3-5%. There are currently no methods to gauge the reliability of PDFF measurements. We propose a method for generating color-coded CSE-MRI estimation confidence maps, using a normalized residual metric to determine PDFF measurement reliability.
Simultaneous T1, T2, and T2* Mapping of the Liver in a Single Breath Hold Using Multi Inversion Spin and Gradient Echo
Authors: Manhard Mary Kate , Pednekar Amol , Wang Hui , Tkach Jean , Dillman Jonathan
Published: August 2023

Parametric mapping aids in the non-invasive evaluation and longitudinal monitoring of diffuse chronic liver disease. Commercially available parametric mapping techniques require multiple scans over multiple breath-holds. A multi-inversion spin and gradient echo (MI-SAGE) method is presented to simultaneously estimate T1, T2, and T2*

at six slice locations in the liver in a single 16s breath-hold. In five volunteers, the MI-SAGE method produced parametric values comparable to those obtained using modified Lock Locker (T1), multiple gradient and spin echo (T2), and multiple gradient echo (T2*) sequences. MI-SAGE offers the potential to significantly shorten the duration of the quantitative MR liver exams.
Variable density Poisson disc acquisition with iterative deep learning reconstruction for highly accelerated 3D T1-weighted abdominal imaging
Authors: Cashen Ty , Ahn Sangtae , Wollner Uri , McKinnon Graeme , Jansen Isabelle Heukensfeldt , Brada Rafi , Rettmann Dan , Zhu Xucheng , Bayram Ersin
Published: August 2023

3D T1-weighted gradient echo imaging is a key component of the MRI assessment of the abdomen, particularly for the identification and characterization of liver tumors, however, significant acceleration is necessary to consistently mitigate respiratory motion artifact. A variable density Poisson disc undersampled acquisition with a densely connected iterative deep convolutional neural network reconstruction was developed to provide next-generation acceleration up to a factor of 10. On retrospectively undersampled data, the technique outperformed compressed sensing reconstruction in terms of normalized mean-squared error and structural similarity; with a prospectively undersampled scan, the technique maintained image quality in terms of artifact and contrast.
Investigating the effects of free breathing on in vivo
13C MRS in the liver at 3T
Authors: Spicer Abi , Francis Susan , Gowland Penny , Bawden Stephen
Published: August 2023

13C Magnetic Resonance Spectroscopy (MRS) in the liver provides the only non-invasive method of studying metabolites in vivo, with standard protocols using multiple averages during a free breathing period. Using a respiratory belt to monitor the breathing cycle and in-house scripts, spectra were binned into inhale and exhale groups categorised as spectra within 2 standard deviations of the average minima/maxima. A systematic reduction in B0 during exhale compared with inhale but minimal impact on average B1 values during an inhale versus exhale. However, no significant changes in Phase angle, area under the curve or FWHM between the data sets.
Combining Convolutional Neural Networks, Multiparametric MRI, and Error Detection to Improve Automated Liver Segmentation
Authors: Gibbons Matthew , Diaz Edgar Castellanos , Koliwad Suneil , Hunt Peter , Schwarz Jean-Marc , Mulligan Kathleen , Lustig Robert , Gugliucci Alejandro , Alba Diana , Erkin-Cakmak Ayca , Noworolski Susan
Published: August 2023

The objective of this study was to generate an automatic liver segmentation method. Two methods were compared. The first, M1, was a Convolutional Neural Network (CNN) trained on proton density fat fraction (PDFF) maps. The second, M2, was the CNN trained on multiparametric MRI (mpMRI) images combined with an error detection protocol. The distributions for Dice similarity coefficient (DSC), volume, and PDFF were improved for M2 versus M1. The DSC mean increased from 0.91 to 0.96. The M2 method was effective in detecting and correcting poor segmentations while significantly reducing processing time as compared to manual segmentation.
Segmentation of Liver Lesions in WB-DWI Using Deformable Registration and Machine Learning Techniques
Authors: Knill Annemarie , Candito Antonio , Winfield Jessica , Larkin James , Turajlic Samra , Koh Dow Mu , Messiou Christina , Blackledge Matthew
Published: August 2023

We present a proof-of-concept study to assess whether deformable registration followed by tissue classification using machine learning (ML) is an effective method for the delineation of liver metastases in whole-body diffusion-weighted imaging (WB-DWI). Deformable atlas-based registration achieves good quality delineation of the liver (Dice coefficient > 70%) and out of three ML models random forest achieved the best F-1 measure for segmenting disease within the liver.
Intravoxel Incoherent Motion Diffusion-Weighted MRI for Prediction of Prognosis in Intermediate Risk Acute Myeloid Leukemia
Authors: Li Jianting , Niu Jinliang , Bian Wenjin , Wu Wenqi
Published: August 2023

The mortality rate for patients with acute myeloid leukemia (AML) is still high. Cytogenetic features are the most important prognostic parameter, and the most appropriate treatment of intermediate risk AML (IR-AML), which accounts for about 60% of AML, is controversial. Our study suggested that the D value obtained from intravoxel incoherent motion (IVIM) could play a potential role in predicting treatment response of IR-AML patients. Moreover, f value and D* value in an IVIM model can independently predict OS of patients with IR-AML. These findings suggest that IVIM parameters can be useful imaging markers to predict prognosis for IR-AML.
Analysis of knee joint injury caused by training of freshmen based on 3T MRI and Automatic Cartilage Segmentation Technology ：A prospective study
Authors: Liu Lingling , Liu Henan , Zhen Zhiming , Zheng Yalan , Zhou Xiaoyue , Raithel Esther , Du Jiang , Hu Yan , Chen Wei , Hu Xiaofei
Published: August 2023

Magnetic resonance imaging (MRI) is the preferred choice for evaluating knee joint injury, which commonly occurs during physical training. In this study, we compared the effects of long-walking and regular daily training on knee joint injuries and cartilage microstructure in 23 young freshmen by analyzing 3D-DESSWE and T2 mapping images using the automatic cartilage segmentation prototype software. Our results demonstrated that regular daily training strengthens the knee joints and protects against knee joint injury by increasing the volume of the knee cartilage. Moreover, knee joint injury caused by short-term long walking and high-intensity pull training was reversible.
Repeatability of Cartilage T2 relaxation times measures at 3T and 7T using quantitative double-echo in steady-state
Authors: Asay Jessica , Gatti Anthony , Desai Arjun , Chaudhari Akshay , Mazzoli Valentina , Kogan Feliks , Gold Garry
Published: August 2023

Quantitative MRI can be used to track subtle cartilage microstructure changes within a subject, which could be helpful in the early detection, treatment, and prevention of osteoarthritis. Increased field strength may offer higher resolution for detecting these changes. This study demonstrated the repeatability of mean T2 relaxation times measured at 3T and 7T. Full thickness cartilage T2 relaxation times at 3T and 7T had excellent ICCs, with CVs at 3T generally lower than 7T. This study suggests 3T and 7T measures are repeatable and can be used in longitudinal studies of cartilage changes.
Peri-conceptional Alcohol Exposure Shapes Placental Functions in Fetal Alcohol Spectrum Disorder
Authors: Stapleton Margaret , Chaillet John , Goetzman Eric , Cortes Devin , Schwab Kristina , Sferruzzi-Perri Amanda , Neeman Michal , Christodoulou Anthony , Wu Yijen
Published: August 2023

Peri-conceptional alcohol (PCA) exposure leading to fetal alcohol spectrum disorder continues to a significant public health concern because alcohol use ceases only after recognition of pregnancy weeks after conception, but the teratogenic damages have already occurred. Our study showed that PCA exposure in mice resulted in compromised placental perfusion and placental capability to adapt to acute hypoxia challenges. Placental abnormalities due to PCA may further exacerbate fetal neurodevelopmental deficits.
In vivo imaging of bone marrow endothelial dysfunction promoting myeloid cell expansion in cardiovascular disease
Authors: Vandoorne Katrien , Lee I-Hsiu , Grune Jana , Zhang Shuang , McAlpine Cameron S. , Schloss Maximilian J. , Nayar Ribhu , Courties Gabriel , Frodermann Vanessa , Wojtkiewicz Gregory , Honold Lisa , Chen Qi , Iwamoto Yoshiko , Sun Yuan , Cremer Sebastian , Iborra-Egea Oriol , Munoz-Guijosa Christian , Ji Fei , Zhou Bin , Adams Ralf H. , Wythe Joshua D. , Hidalgo Juan , Watanabe Hideto , Jung Yookyung , van der Laan Anja , Piek Jan J. , Kfoury Youmna , Désogère Pauline A. , Vinegoni Claudio , Dutta Partha , Sadreyev Ruslan I. , Caravan Peter , Bayes-Genis Antoni , Libby Peter , Scadden David T. , Lin Charles P. , Naxerova Kamila , Swirski Filip K , Nahrendorf Matthias , Rohde David
Published: August 2023

Hematopoietic stem cells at the bone marrow (BM) niche generates excess inflammatory leukocytes harming the heart after a myocardial infarction (MI). Whether MI affects the hematopoietic organ’s microvasculature is unknown. Here intravital microscopy shows that MI triggers endothelial dysfunction, leakage, and angiogenesis in the BM, leading to systemic leukocytosis. These novel findings were imaged by noninvasive PET imaging of integrin αVβ3 activation concomitant with measuring leakiness using dynamic contrast enhanced MRI. Endothelial deletion of Vegf receptor 2 (Vegfr2) curbed emergency hematopoiesis after MI. Our findings establish that MI remodels the vascular BM niche, stimulating hematopoiesis and production of inflammatory leukocytes.
Animal models using C57BL/6J mice are at risk of data misinterpretation due to random occurrences of animals with high levels of brain glutamine
Authors: Tkac Ivan , Rao Raghavendra , Paulsen Megan
Published: August 2023

Wild-type and transgenic mice derived from the C57BL/6J mouse strain are widely used in animal models of different human diseases. However, this mouse strain suffers from random appearances of sporadic congenital portosystemic shunts resulting in extremely high glutamine levels in the brain. In our recent study aimed at effects of maternal obesity on their offspring we found that in 9 out of 31 studied C57BL/6J mice had high levels of brain Gln. The purpose of this abstract is to highlight the awareness of this persisting problem in animal models based on C57BL/6J background strain.
Intravoxel B0 Corrected Image Reconstruction with RF Prephasing
Authors: Whitaker Steven , Nielsen Jon-Fredrik , Fessler Jeffrey
Published: August 2023

Regions with large intravoxel B0 gradients result in a wide spread of off-resonance frequencies within each voxel, causing spins within a voxel to dephase with respect to each other. Using model-based reconstruction to account for this dephasing can help alleviate artifacts from this signal loss, but success is limited in areas of extreme dephasing. We propose a model-based reconstruction method that includes RF prephasing to help mitigate the effects of extreme dephasing. We demonstrate that the proposed approach successfully recovers signal in areas of extreme dephasing and results in lower reconstruction error than model-based reconstruction without RF prephasing.
Multi-domain Neumann Network with Sensitivity maps for Parallel MRI Reconstruction
Authors: Lee Junhyeok , Kang Junghwa , Oh Se-hong , Ye Dong Hye
Published: August 2023

We performed parallel MRI reconstruction from under-sampled k-space data using the Multi-Domain Neumann Network with Sensitivity Maps. The Neumann network solves the inverse problem with recursive neural networks taking account into the forward model. We adapt the Neumann network with the coil sensitivity estimation and k-space data regurlaization to take account into MR physical models. Our proposed method shows uppressed image artifacts and enhanced spatial resolution compared with GRAPPA, U-Net and Neumann network.
Estimating B0 changes in Oscillating Steady State Imaging (OSSI) using an Artificial Neural Network
Authors: Salifu Mariama , Haskell Melissa , Noll Douglas
Published: August 2023

Oscillating steady state imaging (OSSI) is a novel fMRI acquisition method which produces a high SNR T2*-weighted signal. Physiological and drift induced B0 changes cause undesired signal distortions which can significantly diminish functional contrast in OSSI fMRI. Here, we investigated a method of rapidly estimating quantitative B0 field changes from OSSI images using an artificial neural network (ANN) model. Our results demonstrated that this technique can be used to rapidly measure field changes, which has the potential to be used for prospective and retrospective B0 field correction in OSSI.
Realtime dynamic xyz-shimming in the cervical spinal cord
Authors: Papp Daniel , D’Astous Alexandre , Cohen-Adad Julien , Alonso-Ortiz Eva
Published: August 2023

Respiration-induced changes of the magnetic field are an important source of image artefacts in spinal cord MRI. Here, we introduce realtime dynamic xyz-shimming to fully compensate for these distortions in a time-varying (‘realtime”), slicewise (‘dynamic”) fashion, using both in-plane (‘xy’) and through-plane (‘z’) gradients (‘xyz-shimming’).
MEDI-FM: Field Map Error Guided Regularization for Shadow Reduction
Authors: Roberts Alexandra , Spincemaille Pascal , Nguyen Thanh , Wang Yi
Published: August 2023

Morphology Enabled Dipole Inversion (MEDI) is an iterative reconstruction algorithm for Quantitative Susceptibility Mapping (QSM) that is effective in suppressing streaking artifacts by exploiting the magnitude image as a morphological prior. However, contiguous areas of dipole-incompatibility (such as noise) induce shadow artifacts whose spatial frequency components are not sufficiently regularized by the gradient based regularization in MEDI. Regularizing these spatially connected regions reduces shadow artifacts in Morphology Enabled Dipole Inversion based Quantitative Susceptibility Mapping reconstructions.
Isotropic QSM in seconds using super-resolution 2D EPI imaging in 3 orthogonal planes
Authors: Bachrata Beata , Bollmann Steffen , Grabner Günther , Trattnig Siegfried , Robinson Simon
Published: August 2023

We propose a method to generate a super-resolution QSM from three orthogonal 2D EPI acquisitions with anisotropic voxels. Using distortion correction and non-linear co-registration of the individual EPI images with thick slices, a super-resolution EPI image with isotropic voxels was generated and used to compute a QSM. The super-resolution 2D EPI susceptibility maps, as well as the susceptibility values within deep grey matter structures, showed close correspondence to a standard GRE QSM. The net acquisition time was, however, reduced from several minutes to several seconds, allowing QSM in problematic patient cohorts and clinical routine.
QSM with Implicit Regularisation Using Non-Uniform Fourier Transformation
Authors: Fuchs Patrick , Shmueli Karin
Published: August 2023

Direct solutions of the dipole inversion problem in quantitative susceptibility mapping (QSM) are computationally efficient but plagued by streaking artifacts. Here, we have shown that non-uniform sampling of frequency space can achieve additional streaking artifact reduction compared to QSM with thresholded k-space division and state-of-the-art regularisation. By avoiding sampling areas in frequency space where the solution is not well defined, the solution of the ill-posed inverse problem is made more robust and noise amplification is reduced. This approach could be combined with compressed sensing techniques to further improve the QSM reconstruction. This research uses open-source tools from the MR community.
Parkinson’s disease local atrophies measured in the striatum in vivo explain patients’ asymmetric motor symptoms and dopamine loss
Authors: Drori Elior , Berman Shai , Mezer Aviv
Published: August 2023

The striatum is a heterogeneous brain structure with microstructural gradients along its main axes. Changes in its organization are associated with Parkinson’s disease (PD). Yet the spatial variability in the human striatum is not well characterized and is mostly limited to animal and postmortem studies. We developed a non-invasive MRI method for measurement of microstructural gradients along axes of the striatum in individuals in vivo. Using clinical data, we found a T1w/T2 gradient along the anterior-posterior axis of the putamen, which is decreased in PD. This decrease explains the patients’ asymmetries in dopamine loss and motor symptoms.
Examination of nigral volumetric and microstructural changes in prodromal and overt Parkinson’s disease
Authors: Langley Jason , Hwang Kristy , Huddleston Daniel , Hu Xiaoping
Published: August 2023

We examine nigral volume and tissue microstructure in prodromal and symptomatic Parkinson’s disease. Decreases in nigral volume were observed in the symptomatic Parkinson's disease group relative to the control group (p<10-3) and prodromal Parkinson's disease (p<10-3) group. A reduction in nigral volume was seen in the prodromal Parkinson's disease group relative to the control group (p=0.025). An increase in nigral free water was also found in the symptomatic Parkinson’s disease group relative to the control group (p=0.014).
Free-Water Corrected Diffusion MRI Measures Reveal White Matter Disorganization in Parkinson’s Disease Patients with Memory Impairment.
Authors: Mishra Virendra , Sreenivasan Karthik , Caldwell Jessica , Ritter Aaron , Mari Zoltan
Published: August 2023

Diffusion MRI (dMRI) could be used to understand cognitive impairment in Parkinson’s disease (PD). However, single-tensor (ST)-derived fractional anisotropy (FA) measures are biased due to the presence of crossing-fibers and contamination from cerebrospinal fluid (CSF). CSF contamination can be corrected by fitting a bi-tensor model to estimate free water (FW) contamination. Hence, in this study, we compared FW and FW-corrected ST dMRI-derived measures between PD patients (with and without cognitive impairment) and healthy controls (HC) estimated with multishell dMRI data. Our analysis suggests that FW-corrected dMRI analyses are more powerful in understanding WM disorganization in PD patients with cognitive impairment.
Regional patterns of nigral degeneration in the substantia nigra in atypical Parkinsonism using neuromelanin-sensitive MRI
Authors: CHOUGAR LYDIA , ARSOVIC EMINA , GAURAV RAHUL , BIONDETTI EMMA , PYATIGORSKAYA NADYA , LEHERICY STEPHANE
Published: August 2023

We investigated the regional selectivity of neurodegenerative changes in the SNc in patients with Parkinson’s disease (PD) and atypical parkinsonism using neuromelanin-sensitive MRI. We confirmed that neuromelanin volume and signal were reduced in parkinsonian disorders. The spatial pattern of changes differed between progressive supranuclear palsy (PSP) and synucleinopathies. Compared to healthy controls (HC), subjects with PD and multisystem atrophy (MSA), PSP subjects had greater changes in the associative region. Signal-to-noise in the sensorimotor territory was preserved in PSP, but reduced in PD patients and there was a trend in MSA patients. There was no significant difference between MSA and PD.
Neurovascular dysfunction in patients with subjective cognitive decline: A resting-state fMRI study
Authors: Tang Yin , Zhang Ling , Ding Hongyuan , Zhu Yi , Gao Yaxin , Qian Long , Dou Weiqiang , Qi Ming
Published: August 2023

The main goal of this study was to investigate the changes of neurovascular coupling (NVC) in patients at early stages of Alzheimer’s disease. Patients with SCD and MCI were enrolled. Significantly changes of neurovascular coupling have been separately found between SCD, MCI patients and HCs in the regions involved the left Rolandic operculum, left anterior orbital gyrus, right insula, right parahippocampal gyrus, left lingual gyrus, median cingulate and paracingulate gyri and left supramarginal gyrus. In addition, these changes of NVC showed strong correlations with multiple clinical scales. Therefore, NVC can be an effective method for early diagnosis of SCD patients.
DTI to Genetics: The Role of HFE H63D gene mutation in White Matter degeneration in APOE4 carrier of Alzheimer’s disease
Authors: Pang Ran , Wang Jianli , Karunanayaka Prasanna , Kanekar Samgan , Beselia Gela , Kanekar Samika , Connor James R. , Yang Qing X.
Published: August 2023

HFE gene mutation involves iron metabolism, which is shown to directly contribute to myelination process. White matter degeneration in bi-genetic mutation (HFEH63D and ApoE4 allele) carriers was investigated using DTI from the AD Neuroimaging Initiative (ADNI) database. Comparing to the HFEWT/ApoE4+ group, mean diffusivity and radial diffusivity of inferior longitudinal fasciculus in the HFEH63D/ApoE4+ group demonstrated less integrity damage and fewer late-myelination loss with aging reflecting a possible mechanism as HFE polymorphism protective role in partly eliminating ApoE4 being the high-risk factor for AD progressing.
PDFF predicts NASH in obese patients without known liver disease
Authors: Panagiotopoulos Nikolaos , Batakis Danielle , Wolfson Tanya , Agni Rashmi , Zhang Xiaofei , Oechtering Thekla , Tamada Daiki , Harris David , Sirlin Claude , Reeder Scott
Published: August 2023

Proton density fat fraction (PDFF) is not recognized as a discriminator between nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). However, considering the two-hit theory on the pathogenesis of NASH, we hypothesize that in high-risk individuals without known liver disease, MRI-PDFF may predict the presence of NASH. There is a paucity of data to support this hypothesis. Therefore, we examined the predictive value of MRI-PDFF in 29 obese adults without suspected liver disease. We observed excellent diagnostic performance of MRI-PDFF for detecting NASH (AUC=1). If confirmed during this ongoing study, this would constitute a paradigm change in diagnosis of NASH.
Radiomic Variance within Soft Tissue Pathologies Near Total Hip Arthroplasty: A Cluster-based Analysis
Authors: Koch Kevin , Ausman Robin , Neri John , Potter Hollis , Koff Matthew
Published: August 2023

In this exploratory study, radiomic measures were computed across radiologist-segmented image patches within 3D-MSI STIR images collected on symptomatic total hip replacements (THR). Utilizing radiologist classifications of normal, infection, polymeric wear, or metallosis debris for each image patch, principle-component based cluster analysis was deployed to visualize and estimate radiomic distinctions between different soft-tissue pathology classifications. The study results offer insights to future studies seeking to utilize quantitative MR to characterize and classify soft-tissue complications near THR.
Infrapatellar Fat Pad T2 values Associated with Fat Pad Scarring Severity in Individuals with Total Knee Arthroplasty
Authors: Sacher Sara , Neri John , Gao Madeleine , Potter Hollis , Koff Matthew
Published: August 2023

The infrapatellar fat pad (IPFP) has been implicated as a source of pain after total knee arthroplasty (TKA), but regions close to metallic implants are susceptible to metal artifacts in MRI. Multi-acquisition variable-resonance image combination (MAVRIC) based T2 mapping technique can mitigate these artifacts. The goal of this study was to evaluate how T2 values of the IPFP vary with the degree of IPFP scarring. T2 values were shorter and displayed a wider range for individuals with more severe scarring. MAVRIC T2 mapping may be used as a quantitative biomarker of IPFP scarring.
Metabolic bone response to exercise loading is predictive of joint degeneration after 2 years in OA knees
Authors: Baker Janelle , MacKay James , Kogan Feliks , Watkins Lauren
Published: August 2023

Hybrid [18F]sodium fluoride PET-MRI was used to evaluate the relationship between the bone metabolic response to exercise and joint changes over two years in osteoarthritic (OA) knees, including changes in cartilage T2 relaxation times as well as structural changes in bone and cartilage. Regions in OA knees that experienced structural changes over two years had increased PET metabolic bone response to exercise compared to regions that did not. Bone response to exercise may be a useful metric to predict joint changes in OA.
Bilateral homotopic rs-fMRI connectivity strength is not primarily mediated by direct corticocortical interaction
Authors: Jung Won Beom , Jiang Haiyan , Kim Seong-Gi
Published: August 2023

Functional connectivity measured by rs-fMRI have generally shown a bilateral organization in homotopic cortices, presumably related to the intrinsic network of spontaneous activity. Alternatively, cortical silencing suppresses spontaneous output activity from the inactivated site and reduces input to downstream areas. Thus, the decrease in fMRI responses due to cortical silencing is related to the strength of resting-state connectivity between the stimulation site and the connected regions. To examine the contribution of spontaneous neuronal communications to bilateral homotopic connectivity of rs-MRI, we compared the somatosensory network by rs-fMRI with cortical silencing fMRI by optogenetic stimulation of interneurons and anatomical tracing data.
Brain morphometric discrepancies between cynomolgus and rhesus macaques
Authors: Dadarwal Rakshit , Boretius Susann
Published: August 2023

Cynomolgus and rhesus macaques are widely used in biomedical research due to their physiological proximity to humans, and both are often referred to as macaques. However, the brain morphology of cynomolgus and rhesus macaques differs. Interestingly, as shown here by a Jacobian-determinant-based approach, the smaller cynomolgus brain is not only a scaled-down version of the rhesus macaques. For instance, the gray-to-white matter ratio differs significantly between the two species.
Probing compartment-specific diffusion in the brain with 13C diffusion-weighted MRS of hyperpolarized pyruvate and lactate: initial results
Authors: Vincent Mélissa , Gao Xiao , Chaumeil Myriam , Valette Julien
Published: August 2023

Here we propose to use 13C diffusion-weighted MRS of hyperpolarized pyruvate and lactate to probe diffusion properties in distinct compartments of the mouse brain, tentatively extracellular (ECS) and intracellular spaces (ICS). Hyperpolarized 13C-pyruvate is injected intravenously and taken up by the brain before entering cells, where it is quickly converted to lactate, so that 13C-pyruvate concentration in ICS must remain low, while newly produced 13C-lactate should remain predominantly intracellular during the relatively short measurement time. We measure faster diffusion for pyruvate even after removing IVIM effect, suggesting faster diffusion in the ECS, and slow release of lactate in the ECS.
Diffusion MRI protocol optimization for ex vivo mouse whole-brain tractography at 100μm isotropic resolution
Authors: Cosenza Elise , Dallet Laurence , Trotier Aurélien , Ribot Emeline , Petit Laurent , Miraux Sylvain
Published: August 2023

A protocol, including Gadolinium-DOTA perfusion or immersion and Diffusion-Weighted multi-shot Spin-Echo EPI was developed to obtain 100μm isotropic resolution tractogram on ex vivo mouse brain. A 3mM Gd-DOTA concentration combined with 16 EPI shots at short TR (400 ms) allows to whole-brain tractograms of excellent quality and reproducible on the 15 mouse brains analyzed.