bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifying modulation of brain states by optogenetic stimulation of lateral hypothalamus
Authors: Takahashi Kengo , Chen Yi , Pais-Roldán Patricia , Yu Xin
Published: August 2023

The lateral hypothalamus (LH) plays an important role in regulating the brain state changes during sleep and arousal state fluctuation. Although the anatomical projections of LH have been well-investigated, the brain-wide functional map by LH stimulation under different brain states has not been characterized. Here, we applied fMRI to characterize the whole brain activation maps under different brain states during anesthesia in response to LH optogenetic stimulation. We demonstrate that the underlying brain state determines distinct functional mapping features upon LH activation.
Transcranial Focused Ultrasound Suppresses Thalamic Heat Nociceptive Response and Reorganizes Nociceptive Networks in Non-human Primates
Authors: Mishra Arabinda , Yang Pai-Feng , Manuel Tom , Newton Allen , Luo Huiwen , Phipps Marshal , Signoa Michelle , Reed Jamie , Gore John , Grissom William , Caskey Charles , Chen Li
Published: August 2023

MRI guided transcranial focused ultrasound (MRgFUS) is a neuromodulation tool that can excite or inhibit neural activity with high spatial precision and real-time functional feedback. Our goal is to develop a MRgFUS device for human pain therapy. Here, we studied suppressive effects of FUS on a key hub in the thalamus for transmitting peripheral inputs to cortex for pain perception, and mapped changes in effective functional connectivity of thalamic networks using hierarchical clustering. We show that concurrently delivered FUS of moderate intensity suppressed painful heat responses at the thalamus target and induced reorganization of effective connectivity networks.
Real-time Cardiac MRI at 0.55T using through-time spiral GRAPPA
Authors: Fyrdahl Alexander , Seiberlich Nicole
Published: August 2023

Through-time non-Cartesian GRAPPA can be used to enable real-time imaging for evaluation of left-ventricular function. However, it requires arrays with many receiver coils for the parallel imaging reconstruction and gradient systems capable of playing out the specified non-Cartesian trajectories. In this work, we explore the use of non-Cartesian GRAPPA for real-time cardiac imaging on a 0.55T system with lower performance gradients, reduced receiver coils compared to conventional MRI systems.
Test-retest repeatability study of multi-compartment relaxometry for myelin water imaging (MCR-MWI)
Authors: Chan Kwok-Shing , Chamberland Maxime , Marques José
Published: August 2023

In this study, we evaluate the test-retest repeatability of the recently developed multi-compartment relaxometry method for myelin water imaging (MCR-MWI). Cross-protocol repeatability is also studied using 3 GRE protocols with different echo spacing and TR. Good cross-session and cross-protocol repeatability is observed for MCR-MWI. Additionally, tissue parameters along 8 major white matter bundles are studied, and myelin water fraction is the most robust tissue parameter across various protocol settings.
The Utility of Virtual Biopsies for Dataset Augmentation as Applied to AI-Based Detection of Tumor Infiltration in Non-Enhancing Brain Lesion
Authors: Wujek Robert , Prah Melissa , Al-Gizawiy Mona , Schmainda Kathleen
Published: August 2023

Delineation of invasive tumor from peritumoral edematous tissue remains a major obstacle to glioma treatment. To address this problem, a neural network was trained to distinguish between these regions using biopsies paired with colocalized MRI inputs. In addition to histologically confirmed biopsies, virtual biopsies sampled from non-contrast enhancing, FLAIR enhancing regions of non-invasive tumors (meningioma, metastasis) were used with an assumed classification of “non-tumor”. The current work is a preliminary assessment of this assumption and it's impact on model performance.
Investigating the feasibility to assess the alveolar-volume-to-blood membrane thickness with hyperpolarized xenon-129 MRI using simulations
Authors: Ruppert Kai , Achekzai Tahmina , Loza Luis , Amzajerdian Faraz , Xin Yi , Hamedani Hooman , Baron Ryan , Ismail Mostafa , Duncan Ian , Kadlecek Stephen , Rizi Rahim
Published: August 2023

The thickness of the membrane separating the alveolar volume from the capillary blood is difficult measure with the chemical shift saturation recovery (CSSR) hyperpolarized xenon-129 MRI technique. In this work, we used a 1D gas exchange simulation to investigate the concept of measuring the gas-phase depolarization induced by the application of long RF pulses of variable power to extract information about the thickness of this membrane. Our simulations predict that measuring the red blood cell-induced gas-phase depolarization enables an estimation of membrane thickness even when the temporal lag between the rise in dissolved-phase signals cannot be accurately determined.
Investigating the detection capability of RSNs with fMRI at a low field scanner equipped with a high-performance gradient
Authors: Halder Arjama , de Paula Demetrius Riberio , Handler William , Soddu Andrea , Chronik Blaine
Published: August 2023

Preliminary evaluation of the feasibility to perform resting state BOLD fMRI at a low field (0.5 T) MR scanners equipped with a high-performance gradient system by investing the detection capability of RSNs at lower field strengths. There was an overall deterioration in the number of detected regions within all RSNs as the tSNR decreased. However, the 0.5 Evry system that will be used for experimental studies offer a better SNR efficiency than the modelled cases considered here suggesting reasonable capability in extracting RSNs that can potentially provide clinical utility.
Evaluation of a Novel 8-Channel Receive Coil for Speech Production MRI at 0.55 Tesla.
Authors: Munoz Felix , Lim Yongwan , Cui Sophia , Stark Helmut , Nayak Krishna
Published: August 2023

MRI has enabled significant advances in our understanding of human speech production. This application benefits from a lower magnetic field due to reduced off-resonance effects at air-tissue interfaces. Here, we evaluate the SNR and parallel imaging performance of a dedicated speech coil at 0.55 Tesla, and compare it to that of a head-neck coil. Over the upper airway regions of interest, the dedicated coil shows approximately 1.3- to 4.6-fold improvement in SNR efficiency compared to the head-neck coil.
Longitudinal decrement of cerebral blood flow in high-impact sports
Authors: Karimpoor Mahta , Zhao Moss , Mills Brian , Georgiadis Marios , Tran Dean , Goubran Maged , Mouchawar Nicole , Sami Sohrab , Wintermark Max , Grant Gerald , Camarillo David , Zaharchuk Greg , Zeineh Michael
Published: August 2023

Longitudinal changes (over four years) of cerebral blood flow (CBF) using arterial spin labeling MRI were investigated in a population of high-contact sport football college athletes and were compared to low-contact cohort of volleyball athletes. A linear-mixed-effects model was applied to assess CBF (normalized to the cerebellum) by sport (football vs. volleyball), time from baseline MRI, and the interaction between sport and time. Longitudinal analysis showed a prospective decline in perfusion in football compared to volleyball. Fourteen football players experienced an in-study concussion; in contrast to the longitudinal findings, football players exhibited acutely a mild increase in occipital lobe CBF.
Peri-tumoural distribution of lipid composition in postmenopausal patients with oestrogen receptor positive breast cancer
Authors: Cheung Sai Man , Chan Kwok-Shing , Zhou Wenshu , Husain Ehab , Gagliardi Tanja , Masannat Yazan , He Jiabao
Published: August 2023

Early diagnosis is crucial for the prognosis of patients with breast cancer. Postmenopausal women with oestrogen receptor positive cancer account for over half of all new diagnosis, with an imbalance of lipid composition in peri-tumoural adipose tissue. Since oestrogen is primarily modulated by mammary adipocytes, lipid composition monitoring for early sign of heterogeneous lipid deregulation is central to the accurate early detection. Novel chemical shift-encoded imaging (CSEI) allows rapid lipid mapping of whole breast. We set out to elucidate the spatial distribution in the deregulation of peri-tumoural lipid composition in postmenopausal patients with oestrogen receptor positive breast cancer using CSEI.
Retrospective motion correction with structural priors for clinical MRI protocols
Authors: Rizzuti Gabrio , Huttinga Niek , Sbrizzi Alessandro , van Leeuwen Tristan
Published: August 2023

We present a retrospective rigid motion correction and reconstruction scheme for brain MRI with the aid of structural priors. The proposed framework is designed to be applied to a clinical protocol including multiple scans for multiple contrasts, of which some scans are corrupted due to motion during the acquisitions, but at least one is uncorrupted and exploited as an additional prior. We envision a practical workflow that can easily fit into the existing clinical practice without the need for changing the MRI acquisition protocols.
A Mask Guided Attention Generative Adversarial Network for Contrast-enhanced T1-weight MR Synthesis
Authors: Zhang Yajing , Xiong Xiangyu , Sun Chuanqi
Published: August 2023

Image synthesis methods based on deep learning has recently achieved success in reducing the dosage of gadolinium-based contrast agents (GBCAs). However, these methods cannot focus on the region of interest to synthesize realistic images. To address this issue, a mask guided attention generative adversarial network (MGA-GAN) was proposed to synthesize contrast enhanced T1-weight images from the multi-channel inputs. Qualitive and quantitative results indicate that the proposed MGA-GAN can improve the synthesized images with higher quality for details of brainstem glioma, compared with state-of-the-art methods.
Use of MRI- and microscopy-compatible bioreactor for validation of qMRI diffusion measurements via fluorescence microscopy
Authors: LaMonica Megan , Poorman Megan , Hormuth David , Yankeelov Thomas , Keenan Kathryn
Published: August 2023

Quantitative magnetic resonance imaging (qMRI) could complement qualitative MRI analysis by providing quantitative diagnostic information standardized across patients. However, it is difficult to determine how microscopic tissue properties affect MR signal. A microscopy- and MRI-compatible bioreactor was filled with different concentrations of fluorescent beads in gel to explore this relationship. Higher bead count was associated with lower ADC. A 59% ADC decrease was observed at 100 beads/mm3 when varying gradient pulse separation from 16 to 20 ms, illustrating sensitivity to different length scales per the Einstein-Smoluchowski relationship. This work is a step towards validating qMRI with fluorescence microscopy.
Structural abnormalities in patients with early psychosis: a MP2RAGE-based morphometric study at 7T
Authors: Wang Zirun , Cleusix Martine , Jenni Raoul , Conus Philippe , Do Kim Q. , Xin Lijing
Published: August 2023

This study aims to investigate grey matter alterations in early psychosis patients (n = 44) compared to healthy control subjects (n=30). Morphometric analysis using MP2RAGE images at 7T. VBM did not reveal significant cluster after FWE (Family-Wise Error) corrections, but suggested grey matter reduction (uncorrected p<0.005) in the globus pallidus, right thalamus, left inferior temporal gyrus, left superior parietal, left paracentral lobule, left precuneus, right parietal lobe (postcentral gyrus) of patients compared to healthy subjects.
Distortion Correction in Abdominal DW-MRI using Dual-Echo EPI for Improved Evaluation of Crohn’s Disease
Authors: Ariyurek Cemre , Afacan Onur , Kurugol Sila
Published: August 2023

In MR enterography, diffusion-weighted MRI (DW-MRI) is commonly used to evaluate Crohn’s disease (CD). Echo-planar imaging (EPI) used in DW-MRI suffers from geometric distortion due to time-varying susceptibility field changes in the bowel. Hence, we implemented a DW-MRI sequence using a dual-echo EPI with opposing encoding polarities. Thus, the distortion field can be estimated dynamically and corrected retrospectively. The proposed method was evaluated in DW-MRI data acquired on suspected CD patients by visually and quantitatively assessing distortion corrected volumes based on anatomical similarity with T2-HASTE and uncertainty of estimated diffusion parameters of the intravoxel incoherent motion model.
Auditory topographic maps in the congenitally blind brain: Effects of NORDIC de-noising and sensory substitution training
Authors: Hamilton-Fletcher Giles , Chan Russell , Murphy Matthew , Schuman Joel , Nau Amy , Chan Kevin
Published: August 2023

Sensory substitution devices (SSDs) can represent the structure of visual space through sound. To determine whether this representation is topographically organized in the congenitally blind brain, we used NORDIC de-noising and population receptive field mapping (pRF) to correlate functional brain changes to changes in sound stimulus verticality (frequency) and laterality (panning/timing) following SSD principles. We show that NORDIC significantly increased temporal signal-to-noise ratios and activation areas in subjects’ auditory cortices. PRF revealed that auditory topographic maps representing verticality and laterality emerged in occipital-parietal cortices of 3/7 congenitally blind subjects only after 10-minutes of SSD training, indicating rapid cross-modal cortical recruitment.
Association between neurofilament (NF-L) levels and amyotrophic lateral sclerosis (ALS) neurodegeneration patterns in the precentral cortex
Authors: Tilsley Penelope , Moutiez Antoine , Brodovitch Alexandre , El Mendili Mohamed Mounir , Zaaraoui Wafaa , Verschueren Annie , Attarian Shahram , Guye Maxime , Boucraut José , Grapperon Aude-Marie , Stellmann Jan-Patrick
Published: August 2023

Neurofilament light-chain (NF-L) levels in serum and cerebrospinal fluid (CSF) have recently been demonstrated as robust clinical biomarkers in amyotrophic lateral sclerosis (ALS). Nonetheless, the association between NF-L levels and ALS specific neurodegeneration patterns in the precentral cortex, a primarily affected area, has not been fully divulged. Combining 3T and 7T anatomical imaging with NF-L measures, clinical and electrophysiological data, we demonstrated regional-specific degradation within the precentral cortex according to affected limb areas. Further, NF-L levels negatively correlated with cortical thickness within the premotor cortex, suggesting the premotor cortex may be an important contributor to augmented NF-L levels in ALS.
ROI-focused Non-Rigid Groupwise Registration approach for Motion Correction in ASL Renal Blood Flow Imaging
Authors: Oyarzun Anne , Echeverria-Chasco Rebeca , Martin Moreno Paloma L. , Garcia-Fernandez Nuria , Bastarrika Gorka , Fernández-Seara María A. , Villanueva Arantxa
Published: August 2023

Motion correction methods are a prerequisite in multiple-image registration tasks. We implemented a non-rigid groupwise registration method and ROI-focused non-rigid groupwise registration method for renal pCASL images. We evaluated the temporal signal variation in the renal cortex after motion correction using both methods. Motion correction technique shows statistically significant improvement on the tSNR and ROI-focused method performs statistically better.
Whole Brain 1.3 mm isotropic APTw CEST at 3T in under 2 minutes
Authors: Liebig Patrick , Sedykh Maria , Herz Kai , Hsu Yi-Cheng , Fabian Moritz , Mennecke Angelika , Schmidt Manuel , Doerfler Arnd , Zaiss Moritz
Published: August 2023

CEST MRI suffers from long acquisition times and/or limited volume coverage. Here we suggest using a spatio-temporal variable density Poisson disk design for whole brain APTw snapshot CEST. This enabled us to acquire 1.3 mm isotropic whole brain APTw CEST maps in under 2 minutes. All the reconstruction and necessary adjustment steps were implemented within the scanner software, enabling a push-button B0-corrected CEST measurement.
A Software-based TIAMO approach to enable high resolution large FOV body imaging at 7T ultra-high field
Authors: Schulz Jenni , Kraff Oliver , Quick Harald , Scheenen Tom
Published: August 2023

Inhomogeneities across large FOVs are problematic at ultra-high field. We propose a software-based TIAMO implementation to enable similar flip angles across the body without hardware interference on the 7T MR scanner. Using an interleaved and complementary CP+/CP2+ excitation scheme, we acquired water-selective and lipid-selective 3D GRE data at high resolution demonstrating homogeneous signal distribution across the pelvis and lower abdomen.
Cerebellum structural and functional connectivity alteration in relation to freezing of gait in Multiple system atrophy
Authors: Yang Huaguang , Liu Weiyin Vivian , Li Liang , Wen Zhi , Zha Yunfei
Published: August 2023

Cerebellum is responsible for posture and gait control. 67% of patients with multiple system atrophy experienced FOG. Patients with the damaged cerebellar locomotor region had gait-freezing-like symptoms, suggesting that the cerebellum may be involved in the occurrence and development of FOG symptoms. This study suggested that the cerebellum volume atrophy may be involved in FOG development in MSA patients and subsequently induce functional abnormality in the cerebellum-cerebral circuit. This study provided neuroimaging evidence for clinical understanding of cerebellum role in MSA patients with FOG injury.
CBV-Based fMRI at 3T with SS-SI-VASO: Multi-Echo DEPICTING vs Multi-Echo EPI
Authors: Devi Ratnamanjuri , Mildner Toralf , Schlumm Torsten , Möller Harald
Published: August 2023

ME-DEPICTING, a 2D multi-echo readout achieving short echo times was combined with SS-SI-VASO for simultaneous CBV and BOLD measurements at 3T. Results were compared with a traditional ME-EPI readout. Uncorrected time courses of the first echo of ME-DEPICTING demonstrated high sensitivity to functional CBV changes without further BOLD correction, while time courses of S0 and R2* of the multi-echo fit proved almost equivalent for both readouts. Remarkably, a TE dependence was observed in the BOLD-corrected VASO signals obtained by dynamic division with the corresponding control images of VASO indicating a more reliable CBV measure from the S0 fit.
Convolutional neural network predicts task fMRI working memory scores and enables further understanding of working memory network
Authors: Serrano-Sosa Mario , Van Snellenberg Jared , Huang Chuan
Published: August 2023

Interpretable Deep Learning(DL) models are the next step in establishing DL prediction models as accepted tools that provide researchers with data-driven methods to further understand neuroimaging data. In this work, we developed two interpretable DL models to predict Working Memory(WM) scores from task fMRI data to assess neural circuitry pertaining to WM; wherein a traditional Convolutional Neural Network(CNN)(1-3) contained fMRI activation data from cortical vertices as a single image, and the second contained cortical activation data from both hemispheres as separate channels. Overall, the interpretable DL model provided high quality saliency maps potentially displaying novel regions pertaining to WM.
Effects of Autonomic Activity on Brain Fluid Pulsations
Authors: Özbay Pinar , Picchioni Dante , Mandelkow Hendrik , de Zwart Jacco , Wang Yicun , van Gelderen Peter , Duyn Jeff
Published: August 2023

According to recent research, slow waves may increase metabolic waste clearance during sleep, possibly through cerebrospinal fluid (CSF) pulsatile movement. Pulsations can also be caused by direct pressure effects from the cardiac and respiratory cycles, such as deep breaths. To examine this possibility, we designed a cued deep breathing experiment, which was previously demonstrated to result in widespread fMRI global signal reductions. In this work, our findings point to an alternative pathway for the creation of CSF pulsations that relies on autonomic changes rather than sleep.
Preoperative Evaluation of Potential Living Liver Donors with MRI
Authors: Starekova Jitka , Acher Alexandra , Thornton Frank , Reeder Scott
Published: August 2023

The growing need for liver transplantation has led to an increased need for living liver donors. Partial hepatectomy in donors carries significant risk, requiring rigorous preoperative evaluation. Contrast-enhanced MRI and MR cholangiography can assess liver lesions and biliary variants, while chemical shift-encoded MRI and MR elastography detect and quantify fat, iron and fibrosis in unexpected diffuse liver disease. This study summarizes our experience with an extended MRI protocol in 68 potential donors. MRI, in isolation or in combination with other test results identified more than half of patients at risk for surgical complications of liver donation.
Investigation of heating risks during MR-guided microwave ablation using applicators without active shaft cooling
Authors: Ren Liqiang , Woodrum David , Gorny Krzysztof , Felmlee Joel , Thompson Scott , Lu Aiming
Published: August 2023

Execution of MR sequences (RF-heating) and/or microwave energy during MRgMWA may lead to harmful heating at tissue surface with non-cooled MR-conditional applicators. MR imaging was performed using a high SAR sequence and several geometric orientations of phantom/applicators to assess RF-heating impact. Applicator insertion depth (with/without ultrasound gel) and spacing of two applicators on shaft heating were evaluated. Negligible temperature changes due to RF-heating were observed. Significant temperature increases were measured during MWA due to action of MWA system/applicator, which can be mitigated by increasing the applicator insertion depth. Further reduction in temperature change can be achieved by using ultrasound gel.
High temporal-resolution MRI during mild-cold exposure enables the assessment of brown adipose tissue with a low inter-image variability
Authors: Mishre Aashley Sardjoe , Straat Maaike , Martinez-Tellez Borja , Boon Mariëtte , Dzyubachyk Oleh , Webb Andrew , Rensen Patrick , Kan Hermien
Published: August 2023

Brown adipose tissue (BAT) is considered to be a potential therapeutic target against cardiometabolic diseases. Activated BAT combusts intracellular fatty acids leading to a reduction in fat fraction . Both cold exposure and pharmacological stimuli can activate BAT, but the short-term dynamics of BAT activation are unknown. To assess supraclavicular BAT fat fraction dynamics during cold-exposure, we developed a 1-minute-time-resolution MRI protocol using breath-holds and co-registration to minimize motion-artefacts. We demonstrated the validity and feasibility of our image analysis method, and found an inter-image variability of less than 0.1% fat fraction.
Evaluation of Repeated MR Chemical Shift Brain Thermometry in Healthy Humans
Authors: Wang Kelly , Sung Dongsuk , Risk Benjamin , Allen Jason , Fleischer Candace
Published: August 2023

Magnetic resonance (MR) chemical shift thermometry (CST) is the only method that can approximate absolute rather than relative temperature. Our goal was to evaluate repeated body and brain MR CST measurements and the brain-body temperature gradient in healthy human volunteers over a short time period. While brain, body, or the difference between brain and body temperatures were not significantly different, variations in brain temperature between measurements were observed suggesting fluctuations over short time periods. Further investigation into the time scale of brain temperature fluctuations, particularly under controlled conditions to account for physiological changes and neural activity, are warranted.
Fast T1-based MR Thermometry at Low Magnetic Field
Authors: Fiorito Marco , Yushchenko Maksym , Cicolari Davide , Sarracanie Mathieu , Salameh Najat
Published: August 2023

Thanks to the enhanced T1 dispersion and its linear dependence on temperature over the typical hyperthermia range, T1 mapping represents a serious candidate for temperature mapping at low magnetic fields. Nonetheless, T1 acquisitions are typically long and sensitivity if further reduced at low field regimes. Here we propose a Look-Locker-based temperature mapping sequence that takes advantage of the inherently higher signal gathered using a bSSFP approach. Temperatures spanning from 25 to 50°C could be mapped in doped-water samples with a temporal resolution of 20s/slice and with a precision of 2.6±1.9°C.
Fluorinated Tm3+-complexes as molecular temperature sensors
Authors: Mysegaes Felix , Voigt Pauline , Prediger Isabell , Bernarding Johannes , Plaumann Markus
Published: August 2023

Temperature is an important factor for various physiological phenomena. Hyperthermia and hypothermia are only two examples in clinical application. As the resolution of MR data increases, so does interest in the exact determination of the temperature. Molecular sensors offer the opportunity to determine temperature in living organisms. Based on the preliminary investigations of our working group using Ce3+ complexes, the more detailed characterization of Tm3+ complexes was carried out with regard to the temperature sensitivity of the 19F MR signals and, for the first time, also to the toxicity using the example of fibroblasts.
Actively coupled dielectric pads for adaptive B1+ field shimming
Authors: Šiurytė Paulina , de Boer Friso , Akgun Can , Weingärtner Sebastian
Published: August 2023

MRI at high and ultra high field strengths suffers from B1+ inhomogeneities, but B1+ shimming with multiple transmit coils is only available at top-line scanners. Dielectric pads allow for localized B1+ changes, but need to be specifically designed for the scan and anatomy. In this work we explore the use of an actively switchable dielectric device to allow for spatial B1+ correction without the need for multiple transmit coils. Our phantom experiments at 3T show that coupling mini-pockets with barium titanate slurry enables various field configurations that are switchable, localized and significant in magnitude.
Investigation of MR visibility control of water-based (CaTiO3) dielectric padding with iron oxide contrast agent in 7T human brain MRI
Authors: Yoo Seulki , Barg Ji Seong , Park Bo-yong , Lee Seung-Kyun
Published: August 2023

Ultra-high-field MRI provides improved signal-to-noise ratio (SNR) and tissue contrast. However, at the same time, it exhibits stronger RF field inhomogeneity compared to lower-field MRI. Although such inhomogeneity can be mitigated by customized RF coils and parallel transmit methodology, it is often difficult to translate these to clinical use. Recently, a simple and low-cost high dielectric-constant padding has been proposed to improve the quality of 7T brain images in many sequences. Here, we propose a novel approach to suppress the MR visibility of a water-based dielectric padding by controlled addition of iron oxide contrast agent in 7T human brain MRI.
Population-receptive field size estimates are biased by acquisition and preprocessing parameters: a 7T fMRI study
Authors: Windischberger Christian , Linhardt David , Angerer Tessa , Pawloff Maximilian , Ritter Markus , Schmidt-Erfurth Ursula
Published: August 2023

Population receptive field (pRF) mapping is an advanced retinotopic mapping approach. While the size of pRFs has been identified as an important neurophysiological feature, remarkable differences in the pRF sizes across studies has been reported. In this study, we examine the effects of difference in spatial resolution on the pRF size obtained in a group of ten healthy subjects at 7T. Our results clearly show that the amount of spatial dependence between voxels in the visual cortex has a direct effect for the pRF sizes calculated. We can assume similar effects in data sets acquired at different spatial resolutions.
Multi-parametric MRI on a 0.35 T MR-LINAC: application to prostate radiotherapy treatment follow-up
Authors: Marage Louis , Bessières Igor , Quivrin Magali , Léone Aubignac , Peignaux-Casanovas Karine , Truc Gilles , Walker Paul-Michael , Rapacchi Stanislas
Published: August 2023

- The proposed method allows a comprehensive relaxation times estimation (T1, T2, T2*) on MRgRT systems.

- The methodology was validated on phantom and volunteer for accuracy and reproducibility.

- For T1 and T2, less than 5 % coefficient of variation was observed and less than 10 % for the T2*.

- Trends on 5 patients show a slight decrease and a recovery for the T1 and T2 values in both the boost and whole prostate during their treatment.

- The dispersion of T1 and T2 decreased for all patients for the whole prostate whereas it was stable for the boost.
Use of 7 Tesla MRI for frameless pre-surgical planning with skin-adhesive fiducials
Authors: Fagan Andrew , Kirby Krystal , Koons Emily , Welker Kirk
Published: August 2023

This study aimed to investigate the use of 7 Tesla MRI for frameless pre-surgical planning for tumor resection applications. Image geometric distortions at the locations of 10 skin-adhered fiducials were minimized in 7 Tesla images, and compared to in vivo results from a current 3 Tesla frameless imaging protocol. Geometric accuracy of < 1 mm was obtained in 7 Tesla images at the surface of a head-shaped phantom.
Effect of Compressed SENSE on Freesurfer parcellation precision
Authors: Green Michael , Humberg Peter , Ball Iain , Rae Caroline
Published: August 2023

We employed the commonly used software package, Freesurfer to obtain volume, area and thickness measurements from structural MR imaging data acquired using the Compressed SENSE acceleration technique. We assessed measurement reliability via equivalence testing on a series of increasing acceleration factors to provide guidelines for researchers wanting to reduce scan acquisition time while acquiring high-quality data.
Immersive and Interactive On-the-fly MRI Control and Visualization with a Holographic Augmented Reality Interface: A Trans-Atlantic Test
Authors: Velazco-Garcia Jose , Tsekos Nikolaos , Webb Andrew , Koolstra Kirsten
Published: August 2023

We present the computational Framework for Interactive Immersion into Imaging Data (FI3D) for 3D visualization of MR data as they are collected and on-the-fly control of the MRI scanner. The FI3D was implemented to integrate an MRI scanner with the operator who used a customized holographic scene, generated by a HoloLens head mounted display (HMD), to (1) view images and image-generated outcomes (e.g., segmentation) and (2) control the MR scanner to update the acquisition protocol. In this study, the framework linked an MR scanner in Leiden (The Netherlands) and an operator in Houston (USA).
Deep Learning-Based Automatic Lung Segmentation for MR Images at 0.55T
Authors: Chae Rachel , Javed Ahsan , Ramasawmy Rajiv , Xue Hui , Carlsson Marcus , Campbell-Washburn Adrienne , Seemann Felicia
Published: August 2023

High-performance 0.55T systems are well suited for structural lung imaging due to reduced susceptibility and prolonged T2*. Lung segmentation is required to derive metrics of pulmonary function from lung MRI. Convolutional neural networks are effective for lung segmentation at higher field strengths, but they do not generalize to images acquired at 0.55T. This study develops a neural network for automated lung segmentation of T1 and proton density weighted ultrashort-TE MRI at 0.55T. Training data was generated using segmentations by active contours and manual corrections. The proposed network was fast (1.07s) and as accurate as existing semi-automated segmentation (dice coefficient 0.93).
Tumor-liver biomechanical interaction investigated by multifrequency MR elastography in patients with HCC
Authors: Zhou Jiahao , Li Ruokun , Wang Yikun , Guo Jing , Sack Ingolf , Yan Fuhua
Published: August 2023

Tumor-liver biomechanical interaction investigated by multifrequency MR elastography in patients with HCC
Optimization and Analysis of Shielded Loop Resonators towards Modular Coil Arrays
Authors: Sreereddy Manvitha , Bock Michael , Özen Ali
Published: August 2023

Light-weight and flexible RF coil arrays are needed to obtain high SNR which is translated into shorter scan times and to increase patient compliance. Trans­mission line resonators or shielded loop resonators (SLR) are insensitive to the changes in geometry and form, since the tuning is determined by the length of the transmission line. In this study, we propose two parameters and a test setup to evaluate coaxial cables and relate this to the SLR performance. Modularity is demonstrated on facial coil that can be attached to the face masks.
Studying the influence of cryogenic cooling and B0 alignment on Si PIN diode operation in active decoupling circuits
Authors: Wang Wenjun , Zhurbenko Vitaliy , Heredia Juan Sánchez , Larsen Jan Ardenkjær
Published: August 2023

Si diodes can require elevated forward bias voltage to achieve sufficient forward bias current when they are placed in a strong static magnetic field B0 at cryogenic temperatures. This may disrupt active decoupling circuit operation in cryogenic MRI coils. Diodes may still operate if aligned in a certain way with the B0 field, which is studied in this work.
Effect of Matching Network Losses on preamplifier decoupling circuit topologies at room and cryogenic temperature for 3 T 13C applications
Authors: Wang Wenjun , Zhurbenko Vitaliy , Heredia Juan Sánchez , Larsen Jan Ardenkjær
Published: August 2023

The SNR performances of a three- and a four-element matching circuit topologies are compared for the case of 3 T 13C imaging. The benefit to SNR of cryogenic cooling is also compared against the choice of matching networks. Results show that while cryogenic cooling can improve the output SNR by 2–3 dB, a less lossy matching network design can improve the SNR performance by 7–8 dB. The importance of matching network design ought not to be dismissed.
Brain-wide olfactory aberrations in a Parkinson’s Disease mouse model revealed by functional MRI
Authors: Lungu Ruxanda , Fernandes Francisca , Outeiro Tiago , Shemesh Noam
Published: August 2023

Parkinson's disease (PD) is associated with irreparable damage to dopaminergic neurons in brain areas involved in movement. Frequently, a very early symptom is an impaired sense of smell, but the associated brain-wide mechanisms remain unclear. Here, we report on aberrations in BOLD-fMRI responses along olfactory pathway in a PD mouse model. We find decreased activation, especially in the main olfactory bulb, olfactory tubercle and piriform cortex in PD mice when compared to healthy controls upon olfactory stimulation.
Brain Surface Area Alterations Correlate with Gait Impairments in Parkinson’s Disease
Authors: Wei Xuan , Zhu Jinxia
Published: August 2023

In this study, we used surface-based morphometry analysis to evaluate the correlation between structural alterations in the brains of Parkinson’s disease (PD) subjects, impaired cognition, and gait. Our results showed that cortical surface area in the left lateral temporal cortex (LTC) and right inferior parietal cortex (IPC) was significantly larger in the PD subjects compared to the healthy subjects. Furthermore, these cortical structural changes were associated with gait impairments in the PD subjects. Therefore, surface area-based analysis is a useful tool for assessing progression of gait impairments in PD subjects.
Highly Accelerated 4D Compressed Sensing Flow Sequence for Calf Muscle Strain and Strain Rate Tensor Mapping under Isometric Contractions
Authors: Sinha Usha , Malis Vadim , Cunnane Brandon , Jin Ning , Sinha Shantanu
Published: August 2023

The 4D CS-Flow sequence can be applied to image calf muscle motion during isometric contraction in order to extract 3D Strain tensors. The ability to extract the full 3D strain tensors should enable one to answer questions related to muscle deformation anisotropy in the transverse plane, volumetric strain and maximum shear strains.
Measuring brain temperature changes in the rhesus monkey maintained under isoflurane anesthesia using diffusion MRI
Authors: Zhang Xiaodong , Li Chun-Xia
Published: August 2023

Therapeutic hypothermia can improve neurological recovery and reduce mortality in acute stroke. Pharmacologically-induced hypothermia (PIH) has been investigated in preclinical and clinical studies. Usually the core temperature (rectal or esophageal) is measured to monitor the temperature changes of the subject during the treatment. However, it remains unknown how the brain temperature is affected by PIH as the brain temperature can be different from the core temperature and affected by the anesthesia. In the present study, the brain temperature changes of adult rhesus monkeys maintained under isoflurane for over 3 hours were examined and evaluated using diffusion MRI.
Cortical regions in the apex transmodal network show greatest anatomical variability in infant marmosets
Authors: Sawiak Stephen , Quah Shaun , Roberts Angela
Published: August 2023

We created high-resolution paediatric templates of the marmoset brain from infancy to puberty, producing maps of anatomical variability at different ages. We show that greatest variability is present in juveniles and corresponds well with regions in a recently described transmodal apex network of higher order association areas in the marmoset (and human) brain. We hypothesise this time-period of high variability may indicate a period of heightened vulnerability to environmental stressors which may be a causal factor in the development of mental health disorders.
Imaging ex-vivo cynomolgus monkey brain in 150 um isotropic resolution
Authors: Oh Chungseok , Kim Yu Gyeong , Park Jeongheon , Song Youngkyu , Jeon Chang-Yeop , Lim Kyung Seob , Seo Jincheol , Seong Jung Bae , Cho Jee-Hyun , Lee Youngjeon , Lee Jongho , Shin Hyeong-Geol
Published: August 2023

Due to the small size of the cynomolgus brain, imaging the fine structures in the brain is a challenging task. In this study, a sample preparation method is suggested for imaging the ex-vivo cynomolgus monkey brain with sub-millimeter resolution in 7T MRI. Using the proposed method, we acquired 150 um isotropic resolution MR images for whole brain, and the fine structures in the cynomolgus monkey brain was observed.
White matter microstructure changes in a Bcan knockout mouse model
Authors: Tisca Cristiana , Tachrount Mohamed , Lange Frederik , Howard Amy , Wang Chaoyue , Qiu Lily , Tendler Benjamin , Lerch Jason , Martins-Bach Aurea , Miller Karla
Published: August 2023

Recent genome-wide association studies using UK Biobank brain imaging datasets showed associations between microstructural MRI measures in white matter and genetic loci of BCAN, a gene encoding a protein implicated in neurodegeneration and synaptic transmission. To investigate these associations, we acquired ex vivo MRI data in a Bcan knockout mouse model. Our results show significant differences in FA and T2* for some tracts in wild-type males compared to homozygous males, with consistent trends of higher FA and MD across WM tracts. Future histology work in the same brains will reveal the biological changes underpinning these differences.
g-CAMP reconstructs multiple b-value diffusion weighted images from a single RESOLVE k-space
Authors: Elsaid Nahla , Tagare Hemant , Galiana Gigi
Published: August 2023

This work demonstrates the feasibility of reconstructing multiple b-value diffusion-weighted images (DWI) from a single RESOLVE k-space, where each blind was acquired with a different b-value. This multi b-value reconstruction uses the growing Constrained Alternating Minimization for Parameter mapping (g-CAMP) reconstruction method previously presented in ISMRM 2021. This can allow undersampling in the diffusion weighting dimension that is compatible with common undersampling schemes such as GRAPPA and multi-band EPI.
Model-based Image Reconstruction in Looping-star MRI
Authors: Xiang Haowei , Fessler Jeffrey , Noll Douglas
Published: August 2023

Looping star is a silent MRI pulse sequence that can be used for quantitative susceptibility mapping (QSM), T2*-weighted imaging and fMRI. The conventional reconstruction approach for looping star MRI that filters out some the k-space data does not fully model the overlapping echoes, and remove potentially useful signals. This work proposes a model-based reconstruction method that can theoretically resolve the overlapping echos and improve the SNR without increasing the scan time.
Eliminating limits of spatiotemporal resolution in radial stack-of-stars imaging using FID navigators and single-readout binning
Authors: Maatman I. , Ypma S. , Kachelrieß M. , Berker Y. , Block K. T. , Van der Bijl E. , Hermans J. , Maas M. , Scheenen T.
Published: August 2023

Motion-compensated images can be created from motion-binned undersampled radial stack-of-stars data through compressed sensing and image registration. However, for long repetition times or for many partitions, the acquisition time for one radial projection with all phase-encode steps becomes too long to sample the motion via self-gating, which leads to motion artifacts. Therefore, we estimate motion from FID-navigators and perform binning on a single-readout level to gain higher spatiotemporal resolutions. Our methods are tested on a motion phantom and volunteer with gridding and motion-compensated reconstructions. Our results show accurate detection of the motion signal and reduced motion blur in reconstructions.
Automatic reconstruction of arbitrary MRI sequences based on phase distribution graphs
Authors: Endres Jonathan , Dang Hoai , Glang Felix , Loktyushin Alexander , Weinmüller Simon , Zaiss Moritz
Published: August 2023

We propose a method to automatically generate estimators for the exact encoding of a MRI signal, based on the Phase Distribution Graph of a sequence and its simulation. The estimator can then be used on a measurement to split the signal into its differently encoded parts, which enables reconstruction tailored to the sequence used. This approach can result in fewer imaging artifacts since it does not rely on any assumptions about the sequence made up front but on data obtained by a PDG simulation. This also makes it suitable for sequence optimization because it can adapt to changing sequence properties.
DeepFLAIR: a neural network approach to mitigate signal loss in temporal lobe regions of 7 Tesla FLAIR images
Authors: Uher Daniel , Jansen Jacobus , Drenthen Gerhard , Poser Benedikt , Wiggins Christopher , Hofman Paul , Wagner Louis , van Lanen Rick , Hoeberigs Christianne , Colon Albert , Schijns Olaf , Backes Walter
Published: August 2023

In this study we aimed to improve the 7T FLAIR image quality, especially within the temporal lobe regions which are often attenuated due to field inhomogeneities. A neural network using MP2RAGE and T2-weighted images as inputs was set up to generate a new FLAIR-like image. The training was performed on the extratemporal-lobe voxels of the acquired 7T FLAIR image. The deepFLAIR showed a significant improvement in the signal-to-noise ratio and contrast-to-noise ratio in the temporal lobe regions in a number of cases. This study showed the potential to generate FLAIR-like images with reduced inhomogeneity artifacts and improved image quality.
Distortion correction in multi-echo MRI without field mapping or reverse encoding
Authors: Balbastre Yael , Varadarajan Divya , Bas Klara , Ashburner John , Frost Robert , Fischl Bruce
Published: August 2023

Low-bandwidth multi-echo acquisitions suffer from spatial distortions between odd and even echoes caused by B0 homogeneity, causing blurs and loss of effective resolution in sum-of-square images or derived quantitative parameters. We show in this abstract that this curse can also be beneficial, as it allows distortions to be mapped without the need for additional field mapping data. We do so by jointly optimizing a forward model of the data with respect to exponential decay parameters and a smooth distortion map.
The effect of echo train length and TE range on multi-echo quantitative susceptibility mapping.
Authors: Ricciardi Antonio , Karsa Anita , Tur Carmen , Calvi Alberto , Collorone Sara , Grussu Francesco , Battiston Marco , Samson Rebecca , Yannakas Marios , Stutters Jon , Kanber Baris , Prados Ferran , Shmueli Karin , Wheeler-Kingshott Claudia Gandini
Published: August 2023

Quantitative susceptibility mapping (QSM) from multi-echo acquisitions provides more accurate results than single echo, but the optimal choice of echo train length and echo time (TE) range requires investigation. In this work, we showed that QSM values depend on the TE range sampled, so QSM data computed over different TE ranges should not be mixed. Dropping later echoes might help resolve echo-to-echo phase inconsistency artifacts, at the expense of QSM accuracy. Finally, in multi-centre studies using data acquired with different TE settings, covering the same total TE range is preferable to simply matching the number of echoes.
DCE-MRI of blood brain barrier leakage in subjective memory and mild cognitive impairment: The Cognitive Ageing, Nutrition & Neurogenesis Trial
Authors: Sobhan Rashed , Willis David , Gillings Rachel , Thrippleton Michael , Wardlaw Joanna , Minihane Anne-Marie , Berry Narelle , Cameron Donnie
Published: August 2023

As part of the CANN trial, we compared blood brain barrier (BBB) integrity in subjective memory impairment (SMI) and mild cognitive impairment (MCI), two early indicators of Alzheimer’s disease. Also, the impact of a combined flavanol and omega-3 fatty acid-based nutritional intervention on BBB leakage was explored for the SMI cohort. Dynamic-contrast-enhanced MRI was performed to obtain fractional plasma volume (vp) and volume transfer constant (KTrans) parameters. The results suggest that BBB leakage is similar in the SMI cohort and the nutritional intervention tends to be associated with improved BBB parameters.
Neuroimaging of a novel mouse model of Alzheimer’s Disease: The hAβKI mouse.
Authors: Obenaus Andre , Jullienne Amandine , Noarbe Brenda , Keiser Ashley , Trinh Michelle , Kramar Eniko , Beardwood Joy , Dong Tri , Wood Marcelo , AD MODEL
Published: August 2023

Mouse models of Alzheimer’s disease (AD) currently do not recapitulate accurately the human disease. The MODEL-AD consortium has recently developed new mouse models of AD, including the human amyloid β knockin (hAβKI) mouse. Using high resolution diffusion MRI (dMRI) we examined regional changes in the hAβKI male and female mouse across its lifespan (4-18mo). Sex and regional differences were apparent with age, including reduced diffusion metrics in the hippocampus, that mirrored altered learning and memory. Preclinical MR phenotyping allows for cross-species comparisons for biomarker identification.
Accuracy of a commercial high-speed T2-corrected multi-echo single voxel sequence at 3T as a function of R2* for measurement of liver fat content
Authors: Fortier Véronique , McNabb Evan , Mohamed Ahmed , Zakarian Rita , Levesque Ives , Reinhold Caroline
Published: August 2023

Commercial methods for single breath-hold proton density fat fraction (PDFF) quantification in liver can suffer from bias due to the presence of iron. In this work, the PDFF accuracy of a high-speed T2-corrected multi-echo (HISTO) sequence was evaluated at 3T in phantoms at variable R2*, mimicking different iron levels. PDFF errors up to 70% for R2* larger than 150 s-1 were obtained, suggesting that HISTO is unreliable at large liver R2*, as seen with moderate to high iron overload. A Dixon sequence was more accurate at large R2*. Both techniques agreed in patients and phantoms at low PDFF and R2*.