bluuebunny/crossref_metadata_2025 huggingface dataset:
129Xe chemical shift mapping in the lungs with 3D density-weighted MRSI
Authors: Norquay Graham , Collier Guilhem , Schulte Rolf , Wild Jim
Published: August 2023

3D density-weighted MRSI was used to regionally measure the 129Xe chemical shift from xenon in the lung airspaces (G), lung tissue/plasma (TP) and pulmonary red blood cells (RBC) at three lung inflation states. The 129Xe-RBC and 129Xe-G chemical shifts were both found to increase with increasing lung inflation (increase in alveolar pO2) while the 129Xe-TP shift was observed to be lung-inflation independent. The RBC chemical shift maps presented here may be used in patient populations to detect areas of low blood oxygenation in diseases presenting regional hypoxia in the lungs and other well-perfused organs such as the brain and kidneys.
A general framework of synthesizing 129Xe MRI data for improved segmentation model training
Authors: Lu Junlan , Zhang Jesse , Leewiwatwong Suphachart , Dummer Isabelle , Mummy David , Driehuys Bastiaan
Published: August 2023

Quantitative analysis of hyperpolarized 129Xe MRI, segmentation of the thoracic cavity, a crucial step that is often the bottleneck in an otherwise fully automated pipeline. This problem is attractive to solve using deep learning methods, but they are limited by their large appetite for manually segmented training data. To this end, we propose a method to automatically synthesize both 129Xe ventilation MR images and their corresponding thoracic cavity masks using general adversarial networks. This data augmentation technique can accelerate the training of deep learning segmentation models.
Simultaneous measurement of dynamic CBF and CSF signal changes with pseudo-continuous arterial spin labeling
Authors: Im Jae-Geun , Kim Jun-Hee , Park Sung-Hong
Published: August 2023

To measure CBF and CSF signals simultaneously, we proposed a new 2D EPI-based pCASL with overlapping portion of the labeling plane and imaging region. Our results showed that signal difference between label and control scans in the overlapping portion were higher in CSF than in other tissues. In addition, the pCASL-based CSF signals were negatively correlated with CBF, which was more significant than correlations of CBF with other tissues or baseline raw CSF signals. Based on the results, pCASL can be used for simultaneous measurement of dynamic CBF and CSF signal changes with our technique, which warrants further investigation.
Sleep and waste clearance: The association of sleep quality with a 7T IVIM imaging derived proxy of interstitial fluid
Authors: van der Thiel Merel , Drenthen Gerhard , Voorter Paulien , Feiweier Thorsten , Ramakers Inez , Backes Walter , Jansen Jacobus
Published: August 2023

Cerebral clearance is most active during sleep, therefore reduced sleep quality might induce impaired clearance function. Interstitial fluid (ISF) washes waste products from in-between cells through the parenchyma and its volume is found to be regulated by the sleep-wake cycle. Assessment of the ISF-fraction through IVIM can be a potential, non-invasive method to determine sleep-related variations in ISF, without contamination of parenchymal or microvascular diffusion. The current exploratory study investigates the potential of the IVIM-derived ISF-fraction to assess ISF-volume changes in relation to sleep by examining whether these changes are driven by actual hours of sleep or self-reported sleep quality.
Ovariectomized Female Rats Suffer Hippocampal Neuroinflammation and the Blood-Brain Barrier Disruption Easier than Male and Intact Female Rats following Prolonged Exposure of a Hypobaric and Hypoxic Environment at High Altitude
Authors: Zhu Dongyong , He Bo , Wan Yixuan , Zhang Mengdi , Gao Fabao
Published: August 2023

Ovariectomized Female Rats Suffer Hippocampal Neuroinflammation and the Blood-Brain Barrier Disruption Easier than Male and Intact Female Rats following Prolonged Exposure of a Hypobaric and Hypoxic Environment at High Altitude
MRI assessment of cerebral oxygen delivery before and after surgery in infants with congenital heart disease
Authors: Cromb Daniel , Bonthrone Alexandra , Kelly Christopher , Cawley Paul , Pushparajah Kuberan , Rutherford Mary , Simpson John , Edwards A. David , Counsell Serena
Published: August 2023

Reduced cerebral oxygen delivery (CDO2) in infants with congenital heart disease (CHD) is associated with abnormal brain development. We investigated how cerebral blood flow, haemoglobin, and oxygen saturations, which all contribute to CDO2, change following surgery in a cohort of 24 infants with CHD. There was no significant change in CDO2 after surgery (P = 0.62). However, both cerebral blood flow (P < 0.001) and pre-ductal oxygen saturations (P = 0.008) improved significantly, whilst haemoglobin dropped significantly (P < 0.001). Consistent with previous reports, the changes that occur in cerebral blood flow following surgery are dependent on the type of cardiac lesion.
Effect of radiation dose on the recovery of white matter integrity in children treated for medulloblastoma
Authors: Glass John , Sullivan Jared , Guo Yian , Harreld Julie , Li Yimei , Robinson Giles , Gajjar Amar , Merchant Thomas , Reddick Wilburn
Published: August 2023

This study reports on the effects of pediatric medulloblastoma therapy in a population of 105 subjects. Longitudinal white matter microstructure was studied starting with the post radiation examination until approximately two years after diagnosis. The tract-based spatial statistics (TBSS) pipeline was used to combine fractional anisotropy (FA) with individual dosimetry maps before linear mixed effects models were calculated for each voxel. Significant voxels were found for increasing FA over time and a decrease of FA over time associated with higher radiation dose. These results are consistent with a recovery in FA that is attenuated by higher doses of radiation.
Evaluation of quantitative T1 and PD mapping at 7T from an MP2RAGE Sequence optimised to obtain UNI and FLAWS contrast images in a single scan
Authors: Dokumaci Ayse Sila , Vecchiato Katy , Tomi-Tricot Raphael , Bridgen Pip , Eyre Michael , Wood Tobias , Casella Chiara , Sedlacik Jan , Wilkinson Tom , Giles Sharon , Hajnal Joseph , Malik Shaihan , O’Muircheartaigh Jonathan , Carmichael David
Published: August 2023

The Magnetization Prepared 2 Rapid Acquisition Gradient Echoes (MP2RAGE) sequence is commonly used for 3D structural T1-weighted imaging of the brain at 7T and can be optimised to obtain UNI and clinically relevant FLuid and White Matter Suppression (FLAWS) images within one acquisition. In this study, such a protocol was used together with newly derived analytical equations accounting for partial Fourier acquisitions, and B1+ maps, in a dedicated fitting algorithm to produce quantitative T1 and arbitrarily scaled PD-maps. These maps were evaluated in children and adults at 7T demonstrating a significant T1 reduction with age.
Meningiomas with NF2-Loss
Exhibit Strong Radiomics Correlations
on Contrast Enhanced T1-Weighted MRI at 3T
Authors: Sümer Esra , Tan Kübra , Danyeli Ayça Ersen , Can Ozge , Pamir M. Necmettin , Dinçer Alp , Özduman Koray , Ozturk-Isik Esin
Published: August 2023

Meningioma is the most common primary intracranial tumor in adults, and loss of NF2 function in meningiomas has been associated with a more aggressive biology, shorter time to recurrence and shorter overall survival. In this work, radiomics based biomarkers of NF2 copy number loss (NF2-L) have been assessed. Lower grey-level co-occurrence matrix cluster shade with wavelet high-high-low pass filter, lower original image first order minimum, and higher first order skewness with wavelet low-low-high pass filter were observed in tumors with NF2-L compared to tumors with no copy number loss. The classification accuracy of NF2 molecular subsets was 0.80±0.03 (precision=0.85±0.04, recall=0.73±0.05).
Assessment of anal fistula using advanced diffusion-weighted imaging techniques: value of ZOOMit and RESOLVE
Authors: Qin Yue , Jin Dayong , Li Xin , Liu Liyao , Zhu Yinhu , Tian Juan , Qian Yifan , Wang Shaoyu , Jiang Boyuan
Published: August 2023

This study investigated ZOOMit and RESOLVE DWI sequences to compare of the image quality of anal canal and the visibility of the fistula. The results showed that both ZOOMit DWI and RESOLVE DWI obtained high quality images， ZOOMit DWI sequence had higher fistula visibility and SNR of the fistula than those of RESOLVE DWI sequence. Our findings also suggest that ZOOMit DWI can be used as the preferred sequence for anal MR diffusion imaging.
Resolution-dependency of arterial and venous density estimates and vessel distance maps in deep gray matter
Authors: Mattern Hendrik , Speck Oliver
Published: August 2023

The detection of vessel in MRI depends on the imaging resolution used. Hence, subsequent quantification with vessel densities and vessel distance mapping (VDM) is resolution dependent. In this study, the resolution dependency of both metrics was evaluated for arteries and veins in deep gray matter regions by retrospective downsampling of high-resolution vessel images. Quantitative comparison shows that with decreasing resolution the estimated vessel distances increase, while vessel densities decline. The resolution dependency of vessel densities and distances can be modeled linearly. The here found scaling factors may improve inter-study comparability of vessel densities and VDM.
Different Brain Areas Require Different Analysis Models—fMRI Observations in Parkinson’s Disease.
Authors: Torrecuso Renzo , Mueller Karsten , Holiga Stefan , Urgosik Dusan , Vymazal Josef , Sieger Tomas , Růžička Filip , Růžička Evzen , Schroeter Matthias , Jech Robert , Möller Harald
Published: August 2023

Foreseeing how specific brain areas respond in time to a stimulus can be a prerequisite for a successfully conceived fMRI experiment. We demonstrate that in medicated Parkinson’s disease patients, putamen's activation peaks around the onset of tapping but does not persist throughout the tapping block, whereas sustained activation is observed in the motor cortex. Consequently, in the widely used tapping paradigm “On vs. Off L-DOPA”, the drug effect remains undetected if statistical analysis apply a block design instead of an event-related one. Ignoring this information can lead to fallacious conclusions which suggests using different models to investigate different brain regions.
Test-retest reliability of velocity pulsatility in perforating arteries in the basal ganglia at 3T MRI
Authors: van Tuijl Rick , Pham Stanley , Velthuis Birgitta , Ruigrok Ynte , Biessels Geert Jan , Zwanenburg Jaco
Published: August 2023

We studied the test-retest reliability of assessing perforating arteries of the BG with 2D-PC velocity measurements at 3T-MRI, with and without repositioning of the patient. We showed reproducible assessment of Ndetected, Vmean and vPI in the perforating arteries, independent of slice planning. The relative imprecision was smallest for Vmean (12%) and highest for vPI (32%). The interrater-reliability assessment showed high consistency between two raters (mean variability <5% for all parameters). We found very similar Limits of Agreement with and without repositioning, which indicated that uncertainty in measuring these parameters was dominated by scanner and physiological noise, rather than by planning.
T2-dependence of deep and superficial white matter tractography
Authors: Rathi Yogesh , Ning Lipeng , Liao Congyu , Ji Yang , Westin Carl-Fredrik , Zhang Fan , Makris Nikolaos , O'Donnell Lauren , Setsompop Kawin
Published: August 2023

Tractography is typically obtained from diffusion MRI data acquired at a particular echo time (TE). Recent works have shown differential T2-relaxation times of tissue microstructure and fiber tracts. However, estimation of T2 in fiber bundles have typically been done at the last stage (after tractography). In this work, we show that tractography itself is affected by the T2 (and hence TE) of the fibers. Specifically, we show that the ability to trace accurately depends on the T2 of the fiber bundle. This is specifically true for the superficial white matter (u-fibers) which has higher myelination and iron content.
Combining Shape Descriptor and Image Ranking to the Identification of Alzheimer’s Disease in Anatomical Regions using T1-weighted MR Images
Authors: Duarte Kaue , Frayne Richard , Gobbi David , Martins Paulo , de Carvalho Marco Antonio
Published: August 2023

Alzheimer's Disease is one of the most prevalent types of dementia that affects human behaviour and cognitive skills. The progression of this dementia occurs at different rates in distinct parts of the brain, thus also affecting their brain shape. We proposed an approach based on shape feature extraction and image ranking to identify which regions are more predictive for each level of the AD progression. For each stage, we highlighted the sub-cortical regions that suggested a strong correlation in the AD levels. In fact, the results showed a predictive pattern, which aligns to the state-of-the-art.
Robust and efficient R2* estimation in human brain using log-linear weighted least squares
Authors: Edwards Luke , Mohammadi Siawoosh , Pine Kerrin , Callaghan Martina , Weiskopf Nikolaus
Published: August 2023

In vivo maps of R2* in human brain hold promise for neuroscientific investigations. We tested several R2* fitting routines (nonlinear least squares [NLLS; silver standard], auto-regression on linear operations [ARLO], log-linear weighted least square [WLS], and log-linear ordinary least squares [OLS]) for dual flip angle multi-echo FLASH data in simulations and challenging 400 µm resolution in vivo 7T data. Log-linear WLS was found to give a good trade-off between accuracy, precision, and computational time. The method will be available in a future version of the open source hMRI toolbox (hmri.info).
Feasibility of fast whole brain T2 mapping using CAIPIRINHA accelerated SPACE sequences
Authors: Birkl Christoph , Kremser Christian , Rauscher Alexander , Gizewski Elke
Published: August 2023

We investigated whether multiple SPACE sequences accelerated using CAIPIRINHA and acquired with different echo times can be used to obtain high resolution isotropic whole brain T2 maps within a clinical feasible scan time. In a phantom study, we could show that the SPACE based T2 values are comparable with T2 values derived using multiple single spin echo sequences. By reducing the number of echoes we could acquire 1 mm isotropic in vivo whole brain T2 maps in under 3 minutes.
A comprehensive protocol for multiparametric brain MRI
Authors: Radunsky Dvir , Solomon Chen , Blumenfeld-Katzir Tamar , Stern Neta , Filo Shir , Mezer Aviv , Karsa Anita , Shmueli Karin , Soustelle Lucas , Duhamel Guillaume , Girard Olivier M. , Ben-Eliezer Noam
Published: August 2023

The clinical utility of quantitative MRI (qMRI) techniques was demonstrated in numerous pathologies. This work investigated a range of qMRI pulse-sequences and processing methods with proven clinical applicability, aiming to establish a comprehensive and standard qMRI scan protocol for the brain. This multiparametric protocol provides a wide range of numeric maps (e.g., T1, T2, T2*, PD, M0, B1+, water and macromolecular fractions, susceptibility, mean diffusivity, and more) with whole-brain coverage, diverse set of clinical biomarkers, and the ability for stable longitudinal and multi-center investigations. Limitations and practical tips are provided for users interested in quantitative brain imaging.
Variability in Brain Sodium Total Sodium Content (TSC) Mapping Quantification Methods
Authors: Nowikow Cameron , Polak Paul , Noseworthy Michael
Published: August 2023

Throughout the literature, the methods of quantifying total sodium concentration (TSC) brain maps vary. Some studies use a two calibration phantom approach, some use a one calibration phantom approach, and some use anatomical references to quantify the TSC maps. This abstract investigates the variability of using one method versus another to see if a chosen method will inherently bias the resultant maps. It was found that no bias is provided by one method versus another as they provide no significant variance to the data.
The HYPMED PET/MRI Insert for Breast Cancer
Authors: Kuhl Yannick , Naunheim Stephan , Weissler Bjoern , Nadig Vanessa , Schug David , Mueller Florian , Radermacher Harald , Gebhardt Pierre , Gross-Weege Nicolas , Nolte Teresa , Borgo Martino , de Koning Marcel , Mathlener Menno , Koeleman Jeroen , van Duin Frank , Dekker Arold , Schut Wout , van den Berghe Jos , Gareis Daniel , Celik Turgay , Salomon André , Schaart Dennis , Kuznetsov Dimitri , Bakker René , Langen Karl-Josef , Kuhl Christiane , Schulz Volkmar
Published: August 2023

Within the H2020 EU project HYPMED, we have developed a PET insert that can be moved into a 1.5 T MRI Philips Ingenia turning this into a simultaneous MRI-PET device for breast cancer applications. The PET insert consists of two independent PET rings with a field of view of 28$$$\times$$$10 cm² and two dual-channel local receive coils. Each ring consists of 14$$$\times$$$2 detector blocks of which each features a three-layer LYSO crystal array with 1.3 mm pitch. We will present the first PET and MRI results of our system.
MRI compatibility for a novel simultaneous PET/MRI system with scintillator-based RF shielding for preclinical 7 T MRI scanner
Authors: Yin Laiyin , Gross-Weege Nicolas , Nolte Teresa , Weissler Bjoern , Schug David , Schulz Volkmar
Published: August 2023

We present a preclinical PET/MRI system with highly-integrated PET modules in which the RF shielding is implemented on scintillator level for a 7 T Bruker BioSpec 70/20. The PET system's RF housing size is minimized by excluding parts of the scintillator while maintaining the RF shielding properties through the scintillator-integrated shielding. The modules are mounted inside the MRI coil, between resonator and RF screen. MRI compatibility is evaluated in a mouse phantom by means of spurious noise scans and SNR evaluations of standard morphologic sequences, while the PET system is off, idle and measuring. Additionally, postmortem mouse images are presented.
MRI tractography-guided PET image reconstruction regularisation using connectome-based nonlocal means filtering
Authors: Sun Zhuopin , Angelis Georgios , Meikle Steve , Calamante Fernando
Published: August 2023

Diffusion MRI (dMRI) can provide a wealth of information about brain microstructure and connectivity, but its use in PET-MRI image reconstruction has not been exploited. We incorporated dMRI-derived prior information as a regulariser into the iterative PET One-Step Late ﻿Maximum A Posteriori (OSLMAP) reconstruction algorithm. The proposed regularisation method has unique advantages of providing more informative and targeted denoising and regularisation based on the complementary structural connectivity information from dMRI.
An Evaluation of the Diagnostic Quality of Machine Learning Approaches for PET Attenuation Correction in Neuroimaging: A Meta-Analysis
Authors: Raymond Confidence , Michael Jurkiewicz , Orunmuyi Akin , Michael Dada , Ladefoged Claes , Teuho Jarmo , Anazodo Udunna
Published: August 2023

The last decade has seen an increase in the application of machine learning (ML) methods to PET/MRI attenuation correction (AC). This systematic review provides a head-to-head comparison between state-of-the-art ML methods and clinical standards for AC to determine the clinical feasibility of ML approaches PET AC. We extracted numerical values for image quality, tissue classification, regional and global diagnostic performance. The pooled mean relative error for global performance was 0.87 ± 1.3%, the quality of evidence for all outcomes ranged from moderate to very low. Our findings suggest that ML-AC performance is within acceptable limits for clinical PET/MR neuroimaging.
Non-rigid Motion-compensated Whole-heart 18F-FDG PET and 3D T2 mapping in a hybrid PET-MR system
Authors: Schneider Alina , Munoz Camila , Hua Alina , Ellis Sam , Jeljeli Sami , Kunze Karl P , Neji Radhouene , Reyes Eliana , Ismail Tevfik F , Botnar René M , Prieto Claudia
Published: August 2023

Simultaneously acquired 18F-FDG PET-MR imaging and quantitative 2D T2-mapping have been suggested for improved diagnostic accuracy of cardiac sarcoidosis, however misregistration between imaging modalities makes clinical interpretation challenging. Here we used a recently proposed free-breathing motion-corrected 3D whole-heart T2-mapping sequence acquired simultaneously with 18F-FDG PET at a 3T PET-MR system. This approach enables the non-rigid motion-correction for both the 3D T2-mapping and the PET data to the same respiratory position, resulting in aligned volumes for improved clinical interpretation. In this study, we tested this approach in a patient with suspected cardiac sarcoidosis.
Multiparametric MRI, sodium MRI, and PSMA PET of prostate cancer with histological validation of Gleason grade
Authors: Tan Josephine , Akbari Alireza , Fox Matthew , Gaed Mena , Moussa Madeleine , Gomez Jose , Kassam Zahra , Pavlosky William , Chin Joseph , Pautler Stephen , Power Nicholas , Ward Aaron , Bauman Glenn , Thiessen Jonathan , Scholl Timothy
Published: August 2023

This abstract focuses on the development of an imaging assay based on multiparametric MRI and sodium (23Na) MRI to discriminate between low- and high-grade prostate cancer (PCa) lesions, using Gleason grade defined by whole-mount histopathology as the gold standard and PET targeting the prostate-specific membrane antigen (PSMA) as a validation. Data from the first patient (Gleason score 7) demonstrates that PSMA-PET may be superior in detecting PCa lesions in the transition zone and distant metastases while the sensitivity of the current 23Na radiofrequency system in this study is limited to lesions in the peripheral zone of the prostate.
Assessment of gadolinium contrast in the brain using a compressed sense 3D Look Locker sequence after intrathecal contrast administration
Authors: Storås Tryggve , Vatnehol Svein , Ringstad Geir , Emblem Kyrre , Eide Per
Published: August 2023

Quantitative assessment of T1 enhancement after intrathecal administration of Gd-contrast may remove present challenges due to image scaling varying between acquisitions. The compressed SENSE technique allow 3D-Look-Locker-TFE acquisitions with isotropic 1 mm resolution and full brain coverage to be run in clinically feasible times. A clinical example is demonstrated and a small phantom study exploring further improvements based on trade-offs between undersampling and reduced saturation effects is presented.
Investigating the influence of ECG-triggering and respiration strategy on renal perfusion quantification using arterial spin labelling
Authors: Brumer Irène , Jonscher Simon , Gineitaite Indre , Echeverria-Chasco Rebeca , Schad Lothar , Fernández-Seara María , Zöllner Frank
Published: August 2023

In this study, we investigated the influence of ECG-triggering and respiration strategy choice on renal perfusion. To this end, pCASL data of healthy volunteers was acquired at 3T. Acquisitions and processing followed the PARENCHIMA consensus. Processing consisted of groupwise registration, manual whole kidney segmentation and automated cortex/medulla segmentation. All calculated perfusion values were close to the expected range for healthy individuals. Preliminary results from four subjects suggest the influence of cardiac cycle is negligible and the choice of respiration strategy has little effect on renal perfusion values calculated from pCASL data, however additional data is necessary for more complete evaluation.
Impact of breathing induced off-resonance on labeling efficiency in renal Arterial Spin Labeling
Authors: Taso Manuel , Alsop David
Published: August 2023

Renal Arterial Spin Labeling (ASL) is becoming more widely used as a non-invasive technique for measuring renal perfusion and hence renal function. Free-breathing acquisitions with retrospective motion-correction are commonly used as it facilitates workflow and is robust against uncooperative patients. However, PCASL, especially the balanced implementation in which the same net gradient is used for both label and control, has been shown to be sensitive to off-resonance leading to a loss of labeling efficiency. We propose here a pilot study measuring B0 shifts during free-breathing to simulate its impact on free-breathing renal PCASL perfusion imaging.
Evaluation of Automatic Processing of Quantitative Perfusion Images in Patients with Suspected Coronary Artery Disease
Authors: Van Houten Matthew , Feng Xue , Yang Yang , Lozano Patricia Rodriguez , Kramer Christopher , Salerno Michael
Published: August 2023

We developed high resolution quantitative perfusion sequence, along with DCNN network to automatically segment the image sets for motion correction. We deployed the acquisition and post-processing on patients with suspected coronary artery disease and compared the results to their coronary angiography findings. Our sequence and processing successfully match the angiography results.
Impact of cardiac geometry segmentation on MRI-driven estimates of myocardial stiffness in an in vitro synthetic heart model
Authors: Kolawole Fikunwa , Peirlinck Mathias , Cork Tyler , Levenston Marc , Kuhl Ellen , Ennis Daniel
Published: August 2023

MRI-driven computational constitutive modeling can be used to obtain subject-specific myocardial passive stiffness. Verifying the accuracy and precision of this technique requires overcoming the challenge of obtaining ground-truth in vivo myocardial stiffness. We developed a controllable in vitro diastolic filling setup which incorporates a soft heart phantom of known myocardium-mimicking mechanical stiffness and MRI properties. Using the setup we demonstrate that uncertainties in quantifying cardiac reference geometry can lead to errors in estimating myocardial passive stiffness. The in vitro setup is designed to enable us to achieve our overarching goal: to extensively validate in vivo MRI-based myocardial passive stiffness estimation.
Prediction of WHO histological grade of paediatric posterior fossa ependymoma using diagnostic MR imaging and machine learning
Authors: Dury Richard , Lourdusamy Anbarasu , Auer Dorothee , Peet Andrew , Grundy Richard , Dineen Robert
Published: August 2023

Ependymoma is the second most common paediatric malignant brain tumour and has a dismal outcome. WHO histological grade provides insight to prognosis and in most series confers a poor survival. Here we present a method to non-invasively predict the grade of paediatric posterior fossa ependymoma using diagnostic MR imaging (T2w and ADC) and machine learning. We found that WHO Grade II and III tumours can both be predicted with a sensitivity/specificity of 0.7±0.23 and 0.67±0.15 respectively. We believe these results provide the basis for a clinically important aid to decision making in the early stages of treatment.
Difference of stiffness between the fetal and the maternal part of the placenta by virtual magnetic resonance elastography
Authors: Liu Ting , Lu Jiaojiao , Li Junjun , Yang Jian
Published: August 2023

Virtual Magnetic Resonance Elastography (vMRE) is based on IVIM, which does not require any mechanical vibration, can assess the elastography of your organization. dysfunctional placenta had higher stiffness than normal placenta has been found by ultrasound shear‑wave elastography. This study intends to use this vMRE method to study the difference in elasticity between the fetus and the maternal compartment.
Structural Brain Changes during Early Development in Non-human Primate, Common Marmoset: A Longitudinal MRI study
Authors: Uematsu Akiko , Hata Junichi , Fuskushima Makoto , Kishi Noriyuki , Muyarama Ayako , Hayashi Takuya , Okano Hideyuki
Published: August 2023

Neuronal brain development at early life stage is critical for proper function at later life stages. Here, we delineate the maturational process of marmoset brain structure in both macro and micro level at very early life stage with longitudinal multi-modal MRI images. Integrating multi-modal MRI images provided more detailed and accurate information of changes in tissue property especially for frontal brain regions throughout development than a single-modal image analysis.
Developing a Craniofacial Soft Tissue Anthropomorphic Database: Applying Diffeomorphic Template Building Methods to MRI
Authors: Villavisanis Dillan , Khandelwal Pulkit , Zapatero Zachary , Wagner Connor , Cho Daniel , Cheung Liana , Blum Jessica , Swanson Jordan , Taylor Jesse , Yushkevich Paul , Bartlett Scott
Published: August 2023

Craniofacial surgery requires reconciliation of several factors for deformity reconstruction and aesthetic enhancement. Here, we present data in developing a racially and ethnically sensitive anthropomorphic database to provide plastic and craniofacial surgeons with a set of “normal” anatomic measurements to optimize aesthetic and reconstructive outcomes. Images were used to construct composite (template) images with Advanced Normalization Tools (ANTs) and Greedy Tools. Composite templates demonstrated age-appropriate anatomic measurements as proof of concept. Application of diffeomorphic algorithms via ANTs to MRI is effective in developing composite templates representing “normal” soft tissue anatomy, which may aid in objectively quantifying anatomic abnormality.
A Recurrent Encoder-Decoder Network Accelerates T2 Mapping in Knee, Hip and Lumbar Spine
Authors: Tolpadi Aniket , Calivà Francesco , Han Misung , Pedoia Valentina , Majumdar Sharmila
Published: August 2023

Compositional MRI (cMRI) offers sensitivity to biochemical changes that can precede morphological changes in tissues and offer quantitative assessments of musculoskeletal tissue health but suffer from long scan times. We present a recurrent encoder-decoder architecture that predicts ground truth T2 maps from spatially undersampled echo images. Reconstructed maps showed strong fidelity to ground truth in lumbar spine IVDs and knee and hip knee cartilage. Reconstruction errors were below clinically significant T2 changes through R=12 in the knee and lumbar spine and R=8 in the hip. This work marks progress towards a clinical pipeline that reduces cMRI acquisition time.
Feasibility of map recalibration using an in-scan reference system for two MRI mapping cardiac sequences
Authors: Cicolari Davide , Lizio Domenico , Pedrotti Patrizia , Moioli Monica , Lascialfari Alessandro , Mariani Manuel , Torresin Alberto
Published: August 2023

In this work we tested the feasibility of MRI relaxation time maps recalibration by employing an in-scan reference system. This ‘belt phantom’ was characterized through NMR standard spectroscopic technique. Scan-dependent recalibrations of the relaxation time maps could be performed relying on the ground-truth NMR values of the phantom, aiming to clinical intra- and inter-center harmonization. The in-scan reference phantom allowed also, together with the analysis of the standard deviation maps (measured as the 68% confidence bound of the fitted relaxation time value), to evaluate the reliability of the maps and the applicability of the recalibration.
Simultaneous mapping of compartment-specific T2 and T2* with Diffusion-PEPTIDE imaging
Authors: Gong Ting , Fair Merlin , Setsompop Kawin , Zhang Hui
Published: August 2023

Inspired by recent developments in combined relaxometry-diffusion imaging and growing interests in T2* imaging, this study achieves simultaneous compartmental T2 and T2* mapping for the first time. We take advantage of the recently developed diffusion-PEPTIDE imaging technique, which allows for efficient acquisition of diffusion datasets with varying T2/T2* contrast. A relaxometry-diffusion combined microstructure model and a robust multi-stage fitting approach are developed to enable compartmental T2 and T2* mapping. This technique could be a new tool for future neuroimaging studies benefiting from quantification of T2-T2*-diffusion, such as studying iron content related development and pathology.
Optimal acquisition settings for simultaneous diffusion kurtosis, free water fraction and T2 estimation
Authors: Anania Vincenzo , Jeurissen Ben , Morez Jan , Buikema Annemieke E. , Billiet Thibo , Sijbers Jan , den Dekker Arnold J.
Published: August 2023

Fitting the diffusion kurtosis imaging free water elimination model (DKI-FWE) to diffusion MRI data represents an ill-conditioned problem. Fortunately, the conditioning of the model fitting can be improved by explicitly modeling the T2 relaxation dependency of the signal. As a benefit, diffusion and kurtosis metrics robust to partial volume effects can be estimated with conventional techniques. In this work, we use Cramér-Rao lower bound (CRLB) theory to identify optimal acquisition settings that maximize the precision of the model parameter estimates.
Double Quantum Filtered 2H Measurements in Human Subjects Following Deuterium Oxide Loading
Authors: Damion Robin , Cocking Daniel , Franks Hester , Wilkinson Daniel , Brook Matthew , Auer Dorothee , Bowtell Richard
Published: August 2023

Double-quantum filtered (DQF) deuterium spectra were obtained on a 3T scanner from lower leg and forearm muscles of volunteers whose deuterium abundance was increased by approximately 100 times through ingestion of deuterium oxide. Quadrupolar splitting frequencies of approximately 20 – 40 Hz were measured throughout the various muscle groups of the lower leg, with some regions showing little or no splitting. Although the DQF sequence considerably reduces the signal intensity, it has the advantage that it removes any isotropic signal component and therefore reveals an anisotropic component that might have been obscured.
Measuring Deuterium Relaxation Times in Human Brain at 7T following D2O Loading
Authors: Cocking Daniel , Damion Robin , Franks Hester , Wilkinson Daniel , Brook Matthew , Auer Dorothee , Bowtell Richard
Published: August 2023

Deuterium magnetic resonance measurements are of growing interest in the field of metabolic imaging. Four subjects were loaded with D2O to ~1.5% enrichment over a 6-week period for a parallel study of immune cell proteomics. We report T1 and T2* relaxation times of deuterium in HDO measured from cerebral spinal fluid (CSF), white matter (WM) and grey matter (GM) in vivo, using a 7T Philips Achieva scanner with a dual-tuned 2H/1H birdcage coil. 2H T1 values are significantly shorter than corresponding values for 1H in H2O, due to the quadrupolar 2H relaxation, whilst T2* values are comparable to 1H values.
2H multi-echo bSSFP highlights pancreatic ductal adenocarcinomas and distinguishes them from pancreatitis in murine models
Authors: Montrazi Elton , Bao Qingjia , Peters Dana , Sasson Keren , Agemy Lilach , Scherz Avigdor , Frydman Lucio
Published: August 2023

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest of cancers. We recently showed that deuterium metabolic imaging (DMI) can serve as a potential method for PDAC’s detection; we also demonstrated that multi-echo balanced steady-state free precession (ME-bSSFP) can greatly increase DMI’s SNR per unit time compared to CSI acquisitions. This study synergizes these aspects, to provide high resolution maps on the metabolic kinetic of PDAC and pancreatitis mouse models. ME-bSSFP at 15.2T showed that lactate accumulated in different kinds of tumors. In general, glucose was also uptaken by the tumors, and HDO concentrated in them.
Deuterated α-ketoglutarate has the potential to detect the isocitrate dehydrogenase 1 mutation in low-grade gliomas.
Authors: Taglang Celine , Batsios Georgios , Tran Meryssa , Gillespie Anne-Marie , Ronen Sabrina , Viswanath Pavithra
Published: August 2023

2H-MRS is a novel method of imaging flux through metabolic pathways. Here, we show that 2H-MRS can be used to probe the isocitrate dehydrogenase 1 mutation (IDHmut), which catalyzes production of the oncometabolite 2-hydroxyglutarate (2-HG) in low-grade gliomas. Our results indicate that 2-HG production from [3,3’-2H]-α-KG can be specifically observed in IDHmut cells. Importantly, treatment with an IDHmut inhibitor, which is in clinical trials for low-grade glioma patients, results in a significant reduction in 2-HG production from [3,3’-2H]-α-KG in IDHmut cells. Our results point to the potential of [3,3’-2H]-α-KG as a probe of glioma IDHmut status and response to therapy.
Deuterium metabolic imaging of a healthy human brain after oral glucose uptake on a clinical 3T MRI scanner
Authors: Vaeggemose Michael , Schulte Rolf , Laustsen Christoffer , Hansen Esben , Bøgh Nikolaj
Published: August 2023

Deuterium metabolic imaging (DMI) has emerged as a novel biomarker comparable to 18FDG PET by adding quantitative metabolic kinetic capabilities at high field (>3T). The main barrier for widespread clinical adoption, is the availability of high field clinical scanners. The aim of this study is to determine if DMI for neurological applications is feasible on a clinical 3T MRI scanner. Our findings suggests that it is indeed feasible, and that metabolic breakdown product (Glutamine/Glutamate) can be quantified around 120 min after ingestion.
Optimization of a Phase-Cycled bSSFP for Improved SNR-efficiency in Fluorine-19 MRI at 3T
Authors: Lechuga Lawrence , Begovatz Paul , Collick Bruce , Fain Sean
Published: August 2023

The focus of this work is on the optimization of fluorine-19 enabled SPGR, bSSFP, and phase cycled bSSFP (bSSFP-C) pulse sequence parameters to improve signal acquisition efficiency for perfluoropolyether (PFPE) at 3T with a multi-channel coil. Bloch simulations and subsequent experimental validation were performed to determine the parameters to maximize the SNR-efficiency for each sequence. Acquisitions of the optimized SPGR, bSSFP, and bSSFP-C were then assessed for their achieved SNR-efficiency. bSSFP and bSSFP-C demonstrated increased sensitivity compared to SPGR. Feasibility of bSSFP-C with parallel imaging demonstrated the ability to reduce scan times by 2-fold without compromising the qualitative image quality.
1H-31P Cross-polarization: A new frontier to study myelin in white matter
Authors: Ensworth Alex , Knight Cariad-Arianna , Kozlowski Piotr , Laule Cornelia , MacKay Alex , Michal Carl
Published: August 2023

Phosphorus (31P) nuclear magnetic resonance spectroscopy (NMR) has the potential to play a valuable role in the characterization of myelin due to the concentration of 31P present in myelin phospholipids. This study demonstrates the feasibility of detecting 31P through cross polarization (CP) and magnetization transfer (MT) from hydrogen in preserved murine spinal cord and fresh porcine brain. The results demonstrate the detection of myelin phospholipids through these NMR techniques and provide compelling proof of concept for the potential applicability of MT-CP in 31P MRI for non-ambiguous myelin characterization in vivo.
Metabolic information in APT-CEST - A combined 1H and 31P MRS study
Authors: Schuere Jan-Ruediger , Steidl Eike , Neuhaus Elisabeth , Shrestha Manoj , Hattingen Elke , Pilatus Ulrich
Published: August 2023

In this work, APT-CEST imaging in combination with 1H and 31P spectroscopy was performed to investigate 17 patients with different brain tumors. A synergistic analysis should help for a better understanding of the APT-CEST contrasts such as MTRasym with regard to tumor metabolism and further physiological relationships such as the pH-sensitivity.
Portable magnetic resonance based monitoring of MCA occlusion in an ovine sheep stroke model.
Authors: Thomas Dion , Harrison Freya , Little Alice , King Alex , Sorby-Adams Annabel , Tzeng Shieak , Turner Renee , Obruchkov Sergei
Published: August 2023

A custom built single sided magnetic resonance system, generates an external region of homogeneous B0 = 0.2T field, a sweet spot, from which signal can be detected. The device is capable of relaxometry, diffusion and perfusion measurements and was used to continuously monitor progress of an MCA occlusion in a ovine sheep stroke model. The data from the device was compared to image data acquired on a clinical 3T MRI system.
High-resolution vascular imaging of the whole brain at 7T in 15 minutes
Authors: Joseph Arun , Liebig Patrick , Radojewski Piotr , Wiest Roland , Kober Tobias , Hilbert Tom
Published: August 2023

Vascular disease such as arteriovenous malformations can be fatal and lead to brain damage if not detected early. To that end, time of flight angiography is an important tool to visualize vessels, especially the arteries with implications for treatment planning and follow-up. Similarly, susceptibility weighted imaging can be used to visualize veins due to its sensitivity to magnetic field inhomogeneities. However, high resolution TOF and SWI acquisitions can lead to clinically unfeasible scan times. Here, we propose to use compressed-sensing-accelerated high resolution TOF and SWI acquisitions at 7T in <15 minutes to visualize the vascular system of the whole brain.
In vivo, high-resolution Black Blood MRI at 7T
Authors: Peschke Eva , Pravdivtseva Mariya , Jansen Olav , Larsen Naomi , Hövener Jan-Bernd
Published: August 2023

Vessel wall imaging (VWI) is a unique method to depict the vessel walls in vivo but was not applied in small animal models at 7T yet. Here, we developed a setup to emulate T1 contrast and flow to optimize Black Blood MRI in vitro. Using the results, we implemented a RARE sequence that allows in vivo Black Blood MRI with a high resolution of 0.156 x 0.156 mm² and successful flow suppression. Next, the model will be extended for VWI to measure the enhancement of Gadolinium contrast agent.
A multi-channel deep learning approach for lung cavity estimation from hyperpolarized gas and proton MRI
Authors: Astley Joshua , Biancardi Alberto , Marshall Helen , Hughes Paul , Collier Guilhem , Smith Laurie , Eaden James , Blé François-Xavier , Hughes Rod , Wild Jim , Tahir Bilal
Published: August 2023

Functional lung imaging biomarkers, such as the ventilated defect percentage, are computed from segmentations derived from spatially co-registered functional hyperpolarized gas MRI and structural 1H-MRI. Although hyperpolarized gas and 1H-MRI can be acquired in the same or similar breaths, the acquired scans are frequently misaligned. Here, we propose a multi-channel deep learning-based approach to generate accurate lung cavity estimations (LCEs). Across all evaluation metrics, the multi-channel approach significantly outperformed single-channel approaches and generated plausible LCEs across a wide range of pulmonary pathologies. In addition, correlation and Bland-Altman analyses of lung volumes demonstrated strong correlation and minimal bias with expert LCEs.
Deep learning-based synthesis of hyperpolarized gas MRI ventilation from 3D multi-inflation proton MRI
Authors: Astley Joshua , Biancardi Alberto , Marshall Helen , Tofan Malina-Maria , Smith Laurie , Hughes Paul , Collier Guilhem , Hatton Matthew , Blé François-Xavier , Hughes Rod , Wild Jim , Tahir Bilal
Published: August 2023

Hyperpolarized gas MRI can visualize and quantify regional lung ventilation with exquisite detail, but clinical uptake is limited to a few centres worldwide. Alternative, non-contrast techniques have been proposed to image ventilation, including 1H-based surrogates of ventilation from multi-inflation 1H-MRI. Recently, deep learning has shown potential for generating synthetic images in multiple modalities within the lung image analysis field. We propose a 3D multi-channel deep learning approach to synthesize hyperpolarized gas MRI and assess its quantitative performance using several common image synthesis metrics across a large, diverse dataset of lung pathologies using 5-fold cross-validation.
Introducing a correction method for XTC imaging to isolate exchange by compartment
Authors: Achekzai Tahmina , Loza Luis , Kadlecek Stephen , Ruppert Kai , Amzajerdian Faraz , Rizi Rahim
Published: August 2023

HP-Xe Xenon Transfer Contrast (XTC) imaging produces exchange maps between gas (GP) and red blood cell (RBC) and tissue plasma (TP). However, it is difficult to separate the effects of exchange between RBC or TP due to unintended depolarization by the saturation pulse. We introduce a correction method to isolate exchange due to either compartment. The correction method measures depolarization due to saturation at a distance Δ, —the separation between the DP resonances—away from the compartment’s resonance frequency. The corrected maps generated here show that greater correction is needed for discrete pulses and higher power pulses.
Zero Echo Time (ZTE) MRI-Based 3D Collision Modeling of Femoroacetabular Impingement
Authors: Breighner Ryan , Davidson Emily , Potter Hollis
Published: August 2023

To simultaneously improve assessment of patholomorphologies of the hip and reduce the reliance on CT imaging, this study sought to utilize Zero Echo Time (ZTE) MRI to create patient-specific 3D models of the hip and perform in silico kinematic collision simulations to quantify hip range of motion in a cohort of patients with radiologic signs of FAI and hip dysplasia. Range of motion assessments indicate that patients' simulated ranges of motion comport with their radiologically diagnosed conditions.
Feasibility of real-time MRI of the actively moving wrist at 0.55 Tesla
Authors: Lim Yongwan , Cui Sophia X. , Szabo Robert M. , Boutin Robert D. , Chaudhari Abhijit J. , Nayak Krishna S.
Published: August 2023

In this work we show results from a first-in-human study utilizing a high-performance 0.55T system and balanced SSFP (bSSFP) real-time MRI acquisition to assess tissues of the actively moving wrist’s uninterrupted radial-ulnar deviation and clenched fist maneuvers. We show that at 0.55T, bSSFP is less sensitive to off-resonance and banding artifacts that frequently obscure critical wrist structures. We show that the high temporal resolution of 25 ms per frame at high-performance 0.55T enables improved characterization of wrist joint motion. These benefits could make it a promising technology to evaluate dynamic wrist instability.
A personalized-NODDI (pNODDI) pipeline increases sensitivity to microstructural alterations in temporal lobe epilepsy
Authors: Grosso Elena , Wheeler-Kingshott Claudia AM Gandini , D'Angelo Egidio , Vitali Paolo , Palesi Fulvia
Published: August 2023

Several mesoscopic multi-compartment diffusion MRI models have been developed to describe the complexity of water molecules diffusion in the brain by making assumptions. One frequently used model is Neurite Orientation Dispersion and Density Imaging (NODDI). Here, the aim is to propose a personalized-NODDI (pNODDI) by making NODDI assumptions subject-specific. Our findings show that NODDI assumptions impact on output metrics depending on brain region and that these metrics are able to discriminate between healthy and temporal lobe epilepsy subjects. pNODDI provides a mean to personalize a successful and clinically feasible model as NODDI, increasing metrics sensitivity to pathological alterations.
Effect of brain tissue deformation on functional MRI signal variations assessed using biomechanical simulations
Authors: Zoraghi Mahsa , Scherf Nico , Jaeger Carsten , Sack Ingolf , Hirsch Sebastian , Hetzer Stefan , Weiskopf Nikolaus
Published: August 2023

Recent studies on the brain suggest a link between brain function and biomechanics of brain. In this study we develop a novel simulation framework to investigate blood flow-induced deformation caused by increased neural activity in brain tissue considering its mechanical properties. We further investigate its impact in simulated fMRI experiments. Our results demonstrate that the displacement in gyrus induced by local volume and stiffness change might not be directly resolved due to limited fMRI resolution, but can lead to artifacts when interpreting measurements at layer-level resolution. Our findings may help to systematically analyze potential resulting artefacts in high resolution fMRI.