bluuebunny/crossref_metadata_2025 huggingface dataset:
Benchtop NMR for lab-on-a-chip
Authors: Azagra Marc , Portela Alejandro , Patel Hetal , Weerakonda Dian , Yeste Jose , Herrero-Gómez Alba , Fallon Matthew , Benamara Megdouda , Dubois Marc , Antonakakis Tryfon , Ramon Javier , Marco-Rius Irene
Published: August 2024

A benchtop NMR spectrometer has been designed and optimized to monitor real-time metabolism of 3D tissue engineered on microfluidic platforms using hyperpolarization by dynamic nuclear polarisation. We show the design process, which included the modification of a commercial benchtop NMR spectrometer, the design and fabrication of a microfluidic platform for a reliable injection of a hyperpolarized substrate and a constant delivery and renewal of the cell media and its integration with a RF coil for transmit/receive, and the design and fabrication of a sample carrier. We also present our preliminary NMR data using this system.
Development of a MR-compatible bioreactor for 3D cell structure metabolic analysis in real-time for a 60 MHz benchtop NMR spectrometer.
Authors: Mangas-Florencio Lluís , Herrero-Gómez Alba , Azagra Marc , Ellis James , Marco-Rius Irene
Published: August 2024

Bioreactor platforms have been used in HP-NMR applications to analyze cellular metabolism in real-time, however they require complex set-ups and automated controlled systems, limiting their use. We present a system that overcomes these limitations consisting of a 3D printed platform, an NMR compatible 3D cell model and a recirculation circuit for single-shot and longitudinal hyperpolarization-enhanced NMR experiments. The platform presents no signal interference, a media system for biological support, and a straightforward and simplified manufacturing and assembly process. As a proof-of-concept, we present preliminary metabolic data of a 3D HeLa cell model analyzed with our bioreactor.
Falling conductive loop: A simple analytical model for magnetic damping
Authors: Lee Seung-Kyun
Published: August 2024

The motion of a conductive object is profoundly affected by the presence of a strong magnetic field. A conductive loop falling inside an MRI magnet can serve as an analytically solvable model to explore magnetic damping. We present a pair of magneto-mechanical coupled equations to describe its motion and verify their solution with experimental data. A simple formula for the loop's falling time was obtained, which indicates that magnetic damping is proportional to B02.
Design and Optimization of a MultiPINS Prepulse for Two-dimensional Ultrashort Echo Time Simultaneous Multi-slice Pulse Sequences
Authors: Reich Jason , MacMillan Erin , Feldman Rebecca
Published: August 2024

It has been challenging to achieve ultrashort echo times with two-dimensional acquisitions. However, the use of a prepulse and a whole volume hard excitation may address these limitations. In addition, such a pulse sequence would allow for the use of simultaneous multi-slice pulses to reduce scan times. We aim to design a low specific absorption rate, short duration MultiPINS prepulse that excites a slice profile with sharp, narrow slice gaps. Optimization suggests that a pulse with time bandwidth product (TBW) of 49.43 is optimal, but further investigation suggests that a pulse with TBW as low as 36 may be feasible.
Analytical expression for gradient eddy current-induced power dissipation in a thin conductive shell: A model for RF shield heating
Authors: Lee Seung-Kyun , Tarasek Matthew , Hua Yihe , Park Keith , Kang Daehun , Bernstein Matt , Foo Thomas
Published: August 2024

Gradient-induced eddy current in an RF shield can cause significant temperature increase in the patient bore. As gradient coils produce higher amplitudes with faster rise time, understanding and controlling eddy-current heating become more and more important for patient safety and device longevity. Through time-domain analysis, we have derived a mathematical formula that relates the eddy-current heating of a uniform conductive shell to the properties of the conductor and the mean-square slew rate of the gradient waveform. The theoretical prediction was tested by experiments performed on a high-performance head-only gradient (MAGNUS) system.
Subject Specific Prediction of Gradient-Induced E-fields Using a Multivariate Linear Modeling Approach
Authors: Ertan Koray , Roemer Peter , Rutt Brian
Published: August 2024

Peripheral Nerve Stimulation (PNS) remains as a limiting factor for gradient coils despite the recent advances. PNS thresholds varies significantly across population group. In this study, E-fields are simulated on simplified body model population with randomized realistic body dimensions and different patient landmark positions. It is shown that multivariate linear model with body dimensions and z-offset location as the independent variables can accurately predict the maximum E-field on the surface which can also be used to predict PNS thresholds. This simple multivariate model may pave the way to estimate subject specific PNS thresholds using simple anatomical measurements.
Modelling the gradient system as linear and time-invariant: Do the assumptions break down at higher field strength?
Authors: Sommer Stefan , Köstler Herbert , Scholten Hannah
Published: August 2024

The gradient system transfer function (GSTF) is a broadly used model to characterize the gradient chain and correct for imperfections e.g. in non-Cartestian sampling trajectories. The model assumes linearity and time-invariance (LTI) of the system. In this work, we indirectly examine the LTI compliance across two different field strengths by comparing different GSTFs based on varying subsets of input gradient shapes for the model computation. Overall, only small changes in the GSTF were observed upon adding different input gradients for the system characterization. However, the differences were more pronounced at 7T compared to 3T.
The effects of RF channel numbers on |B1+| mapping using the BSS method
Authors: Ren Yinhao , Gao Yunyu , Qiu Bensheng , Nan Xiang , Han Jijun
Published: August 2024

In the BSS method, WA and MLE as two methods in channel combination were proposed in |B1+| mapping for the multi-channel coils. We investigated the effects of the channel numbers on the performance of WA and MLE. The results showed the accuracy of |B1+| maps improved with the channel numbers increasing, even at low SNR. However, this trend slowed down when the channel numbers reached 24 or above. The RSD of WA and MLE was reduced to 6.6% and 4.0% for 24-channel coils, but the improvements were only 1.0% and 0.7% for 32-channel coils at SNR=25.
Open-source, low-cost device for visualizing static magnetic field components at 0.25 T and 3 T
Authors: Narongrit Folk , Ramesh Thejas , Terlep T , Susnjar Antonia , Rispoli Joseph
Published: August 2024

We present a low-cost (<$17 USD per channel), open-source, and scalable prototype for visualizing the three-axis static magnetic field components up to 3 T based on the GaAs Hall effect technology. The prototype showed accuracy and stability on the bench and accurately measured field values in a 0.25 T electromagnet and a 3 T MRI scanner.
Design and Test of a Flexible Two-row CTL Array and Its Detunable Resonant Elements for 10.5T MR Imaging
Authors: Zhang Xiaoliang , Waks Matt , DelaBarre Lance , Payne Komlan , Ugurbil Kamil , Adriany Gregor
Published: August 2024

A flexible patch array using small-sized 5-cm coaxial transmission line (CTL) resonators is designed, constructed and tested, aiming for human head imaging at the ultrahigh field of 10.5T. Bench tests on decoupling performance among resonant elements are shown. For full utility, a detuning circuit is successfully developed, showing the ecellent detuning capability for 5-cm small CTL loops at 447 MHz. This study suggests that it is possible to build high-density receive-only coil arrays using small-sized CTL resonators at 10.5T.
Data-Driven Discovery of mechanical models directly from k-space data: initial results with an actively forced linear elastic system.
Authors: Heesterbeek David , van Riel Max , van den Berg Cornelis , Sbrizzi Alessandro
Published: August 2024

We propose a framework for data-driven discovery of the governing biomechanical equations for soft tissue directly from k-space data. This framework is based on principles from Spectro-dynamics, a novel method to infer dynamical information directly from severely undersampled spectral data with high spatiotemporal resolution, and sparse regression. As a proof-of-concept, the underlying equations of motion are identified for an actively forced linear elastic system using experimentally obtained k-space data. The systems studied in this abstract are successfully identified with errors of less than 2.5% on the system parameters, and their respective displacement fields are reconstructed accurately.
Fat/water separated & SMS accelerated pseudo 3D PROPELLER
Authors: Norbeck Ola , Rydén Henric , van Niekerk Adam , Avventi Enrico , Sprenger Tim , Skare Stefan , Berglund Johan , Skorpil Mikael
Published: August 2024

By combining thin slices, PROPELLER acquisition, SMS acceleration and chemical shift encoding with asymmetrical gradients reformattable pseudo 3D volumes can be acquired. These volumes are, in contrast to 3D RARE volumes, efficiently chemical shift encoded, less susceptible to T2-blurring and less sensitive to motion.
Accelerated parameter mapping in the k-p domain via nonconvex low rank constraint
Authors: Yan Kang , Meyer Craig
Published: August 2024

A nonconvex low rank regularization (NLR) was proposed to accelerate parameter mapping in the k-p domain. The NLR uses weighted nuclear norm minimization (WNNM) to obtain an optimized solution by differently penalizing singular values, in comparison to traditional low rank methods. The performance of the proposed algorithm was demonstrated for T2 mapping of the kidney. Our study demonstrated that the proposed algorithm outperformed k-p domain-based compressed sensing and L&S algorithms.
Dynamic lung water imaging during exercise stress
Authors: Seemann Felicia , Javed Ahsan , Khan Jaffar , Bruce Christopher , Chae Rachel , Yildirim Korel , Potersnak Amanda , Wang Haiyan , Ramasawmy Rajiv , Lederman Robert , Campbell-Washburn Adrienne
Published: August 2024

Dynamic quantification of lung water during exercise stress is of clinical interest for early diagnosis of heart failure. In this study, we demonstrate a method to derive quantitative time-resolved lung water density maps from a continuous 3D MRI acquisition during supine exercise stress by using a motion corrected sliding-window image reconstruction. An animal model of dynamic lung water accumulation was used to validate the method, and feasibility was demonstrated in healthy subjects imaged in transitions between rest and exercise, measuring a lung water density increase of 23±10% during peak exercise.
Dynamic single slice 2D coronal lung MRI detects metronome-paced tachypnea (MPT) - induced hyperinflation in COPD patients
Authors: Müller Robin , Klimeš Filip , Voskrebenzev Andreas , Behrendt Lea , Kaireit Till , Glandorf Julian , Zubke Maximilian , Wernz Marius , Kern Agilo , Prince Martin , Cooper Christopher , Barr R. , Hohlfeld Jens , Vogel-Claussen Jens
Published: August 2024

Metronome-paced tachypnea (MPT) is a technique where a patient breathes rapidly with a fixed frequency (40 breaths / minute). MPT induces dynamic hyperinflation and allows investigation of potential stress-driven effects on ventilation parameters. Fifteen patients with chronic obstructive pulmonary disease (COPD) and thirty healthy subjects underwent MRI with a 2D coronal lung MR image acquired repeatedly with a temporal resolution of 200 ms during resting tidal breathing (RTB) and MPT. The decrease of fractional ventilation (FV) and the increase of end-expiratory lung area (EELA) during MPT was significantly higher in COPD patients compared to respective healthy subjects.
129Xe gas transfer lung MRI before and after bronchodilator inhalation in patients with asthma and/or COPD
Authors: Marshall Helen , Collier Guilhem , Smith Laurie , Chan Ho-Fung , Hughes Paul , Capener Dave , Bray Jody , Joseph Sinoy , Munro Ryan , Rodgers Olly , Ball James , Stewart Neil , Norquay Graham , Brook Martin , Armstrong Leanne , Hardaker Latife , Fihn-Wikander Titti , Hughes Rod , Wild Jim
Published: August 2024

Lung ventilation increases after bronchodilator inhalation in patients with asthma or COPD but there is little MRI data on how bronchodilator inhalation affects gas transfer. 117 patients with asthma and/or COPD were scanned with 129Xe gas transfer MRI before and after bronchodilator inhalation. There were no significant changes in red blood cell (RBC) / membrane (M), RBC/gas or M/gas in response to bronchodilator when all patients were considered, but RBC/gas and M/gas increased post-bronchodilator in a sub-group of patients with asthma+COPD. The amplitude of RBC oscillations increased post-bronchodilator in patients with asthma or COPD, and when all patients were considered.
The value of CMR feature tracking (FT) technique in quantitative assessment of left ventricular myocardial strain in cardiac amyloidosis (CA)
Authors: Liu Jia , Qiu Jianxing , Li Wei , He Jiangkai , Zhao Kai , Lian Jianxiu
Published: August 2024

Subjects were divided into light-chain amyloidosis (AL-CA), transthyretin-related amyloidosis (ATTR-CA) and control group. CMR-FT technique was used to measure apical, middle and basal strain of left ventricle. Results showed ICC value was higher than 0.9 in all strain parameters, and meanwhile all strain parameters in AL-CA group and ATTR-CA group were lower than those in control group except for apical RS. However, there was no statistical difference between the AL-CA group's and ATTR-CA group. Strain evaluation could evaluate patients of CA, which may provide evidence for the treatment and diagnosis of CA.
MRI for the assessment of pre-treatment regional cardiac dysfunction in thoracic cancer patients
Authors: Ibrahim El-Sayed , Sosa Antonio , Stojanovska Jadranka , Puckett Lindsay , Gore Elizabeth , Bergom Carmen
Published: August 2024

Radiation therapy (RT) plays a key role in treating thoracic cancer, although the incidence of RT-induced cardiac complications could be as high as 33%. Nevertheless, characterization of baseline heart function, myocardial tissue characteristics and hemodynamic parameters in this patient population is not well elucidated, which was investigated in this study. The results revealed suboptimal cardiac function (both systolic and diastolic) and associations between different MRI cardiovascular parameters at baseline. Therefore, the condition of the cardiovascular system at baseline should be taken into consideration as a contributing factor in the development of RT-induced cardiotoxicity in thoracic cancer patients.
Assessment of early anthracycline-induced cardiotoxicity using segmental strain of cardiac magnetic resonance : an animal study
Authors: liu junqi , luo qianfeng , qi wanyin , xiao zhengyuan , zhang xiaoyong , kou xingyuan , chen jing
Published: August 2024

This study investigated segmental strain to evaluate early anthracycline-induced cardiotoxicity on a 1.5T MR system in New Zealand rabbits models. The apical lateral wall and the anterior apical wall have a statistical difference corresponding to the pathological results in the second week. The ejection fraction showed statistical difference at the eighth week, while the global strain was not even statistically significant. The result showed that the peak segmental strain was earlier than the peak global strain and cardiac function, which may provide an effective and convenient monitoring method for chemotherapy patients.
Analysis of segmental strain in identifying HCM with and without outflow tract obstruction
Authors: Lian Jianxiu , Liu Shengliang , Li Yunling , Wang Guokun , Wang Xueying , Li Ye , Xu Xiaofang , Zhao Yanming
Published: August 2024

Hypertrophic cardiomyopathy (HCM) can be divided into two types according to pressure gradient of left ventricular outflow tract, which means different prognosis and risk stratification. Feature tracking technology can be used to calculate strain value in three orientations and evaluate the ability of myocardial deformation. Our results showed that strain differences can be detected between HCM and control group. Segmental strain and torsion also showed significant differential value between hypertrophic obstructive cardiomyopathy (HOCM) and hypertrophic non-obstructive cardiomyopathy (HNOCM) group. Our study may provide evidence in differentiating HOCM and HNOCM for further treatment.
Early evaluation of subclinical cardiotoxicity in HER2-positive breast cancer patients with low-moderate cardiovascular risk using MRI
Authors: Cheng Sainan , Wang Jianwei , Wang Yawen , Qi Linlin , Li Fenglan , Liu Jianing , Chen Jiaqi , Fan Yang , Xie Lizhi
Published: August 2024

This study explored the early cardiac changes in HER2-positive patients treated with HER2-targeted or anthracycline therapy through cardiac MRI. The results showed frequent signs of subclinical cardiotoxicity after short-term anti-cancer therapy, despite with low-moderate cardiovascular risk. T1 mapping showed the capability for early detection of pathological myocardial changes before cardiac contractile dysfunction. In HER2-positive breast cancer patients, cardiotoxicity surveillance is important and should be carefully done even with low-moderate cardiovascular risk, especially for those received anthracycline-based therapy.
Cardiac energetic deficit in a rat model of Heart Failure with Preserved Ejection Fraction (HFpEF)
Authors: Goodman James , Quirk James , Ge Xia , Zhang Yao , Roth-Flach Rachel
Published: August 2024

Cardiac energetics in patients with heart failure with preserved ejection fraction (HFpEF) may serve as a useful biomarker of disease status and therapeutic intervention. To evaluate the potential suitability of this endpoint as a biomarker in preclinical research, we assessed cardiac energetics in the ZSF1 obese rat model of HFpEF and ZSF1 lean control. This preclinical HFpEF model exhibited similar cardiac energetic deficits as do humans with HFpEF, indicating that that the PCr/γATP ratio may be a useful translational biomarker of disease status and intervention.
Global Longitudinal Strain Associates with Adverse Outcomes in Nonischemic Dilated Cardiomyopathy without Myocardial Scar
Authors: Xiang Xiaorui , Chen Xiuyu , Zhao Shihua
Published: August 2024

Despite late gadolinium enhancement (LGE) have already proved a strong association with adverse outcomes in non-ischemic dilated cardiomyopathy (NIDCM) patients, for those who with negative LGE, mortality remains a clinical issue. This study therefore aimed to investigate the prognostic impact of cardiac magnetic resonance (CMR) feature tracking derived strain in NIDCM patients without myocardial scar.
Subendocardial Involvement as an Underrecognized LGE Subtype Related to Adverse Outcomes in Hypertrophic Cardiomyopathy
Authors: Yang Shujuan , Zhao Shihua
Published: August 2024

In a retrospective cohort study, 497 consecutive HCM patients with LGE confirmed by cardiac MR were collected. The risk of cardiovascular events increases with per percentage increase in LGE extent in HCM patients with extensive LGE (>15%). While instead of LGE extent, the subendocardium-involved LGE pattern, an underrecognized phenotype in HCM, is related to the adverse outcomes in patients with non-extensive LGE (<15%), especially for heart failure-related outcomes. RVIP LGE is commonly seen in HCM, but this LGE location does not merit a prognostic value.
Metabolic imaging of response to therapy in pediatric diffuse midline gliomas
Authors: Batsios Georgios , Taglang Celine , Tran Meryssa , Gillespie Anne Marie , Viswanath Pavithra
Published: August 2024

Diffuse midline gliomas (DMGs) are lethal pediatric brain tumors. DMG patients are typically treated with radiation in combination with an experimental agent in clinical trials. ONC206 is a novel drug with promising efficacy in preclinical models. Successful clinical translation and deployment of ONC206 requires the identification of companion biomarkers of treatment response. Therefore, the goal of this study was to identify magnetic resonance spectroscopy (MRS)-detectable biomarkers of response to ONC206 in preclinical DMG models. Our studies identify a combination of 1H- and 2H-MRS-detectable biomarkers that serve as imaging biomarkers of early response to ONC206 in mice bearing intracranial DMG xenografts.
Implicit Temporal-compensated Adversarial Network for 4D-MRI Enhancement
Authors: Wang Yinghui , Li Tian , Xiao Haonan , Cai Jing
Published: August 2024

In this study, we proposed and evaluated a deep learning technique for refining four-dimensional magnetic resonance imaging (4D-MRI) in the post-processing stage. More specifically, we designed an implicit temporal-compensated adversarial network (ITAN) based on the intrinsic property of 4D-MRI to improve image quality with neighboring phases. It can overcome its inherent challenges of data deficiency, misalignment between training pairs, and complex texture details. The qualitative and quantitative results demonstrated that the proposed model can suppress the noise and artifacts in 4D-MR images, recover the missing details and perform better than a state-of-the-art method.
Multi-parametric MRI-based Radiomics integrated with Clinical Features for Predicting the Ki-67 Labeling Index in Nasopharyngeal Carcinoma
Authors: Wang Zhuo , Chen Zhiqiang , Chen Xiaohua , Zhang Shaoru , Liu Shili , Zhang Ruodi , Zhou Yunshu , Xiong Yuhui , Wang AiJun
Published: August 2024

To investigate the value of a nomogram based on multi-parametric MRI-based radiomics combined with clinical imaging features in predicting the Ki-67 LI in nasopharyngeal carcinoma. Least absolute shrinkage and selection operator (LASSO) regression was performed to select radiomics features. A nomogram was established using multivariable logistic regression. The receiver operating characteristic (ROC) curves, calibration, and decision curves were performed to evaluate the predictive performance of the different models. The nomograms constructed by integrating radiomics score (Rad-Score) with clinical imaging factors outperformed the clinical or the radiomics models alone.
A pilot study of brain glutamine levels in schizophrenia and control subjects: relationship to blood ammonia and cognition
Authors: Barker Peter , Thomas Cykyra , Senapati Dillip , Özdemir İpek , Etyemez Semra , Yoon Mark , Kamath Vidya , Coughlin Jennifer
Published: August 2024

It has previously been shown that brain glutamine (Gln) may be elevated is some patients with schizophrenia (Sz), and associated with cognitive deficits. Underlying causes of Gln elevation in Sz are unclear, but may be related to increased blood ammonia (NH3) levels. Brain Gln was measured in 12 subjects (5 Sz, 7 healthy controls (HC)) using 7T MR spectroscopy; brain Gln was found to correlate with blood NH3 levels (p < 0.05). and negatively correlate with measures of cognitive performance. This preliminary study therefore supports the hypothesis linking blood ammonia, brain Gln and cognitive performance.
Quantitative Susceptibility Mapping and Polygenic Risk Scores in subjects with unusual and psychotic experiences obtained from the UK Biobank
Authors: Garcia-Saborit Marisleydis , Milovic Carlos , Villaman Camilo , Perez-Palma Eduardo , Repetto Gabriela , Crossley Nicolas , Tejos Cristian
Published: August 2024

We evaluated a cohort of subject with unusual and psychotic experiences and control subjects obtained from the UK Biobank, and we studied the relationship between susceptibility (QSM) in deep brain nuclei and polygenic risk scores (PRS) of genetic variants associated to psychosis. Although we found significant differences between patients and controls for QSM and PRS, we did not find any relationship between these two variables.
Alternations of Brain Local Cortical Thickness in Adult Schizophrenia: A Surface-Based Morphometry Meta-Analysis
Authors: Sun Shilin , Xiao Shu , Gong Jiaying , Tang Guixian , Qian Long , Wang Ying
Published: August 2024

Numerous neuroimaging studies have revealed abnormalities in specific brain regions in schizophrenia (SCZ), but results have been inconsistent. We conducted a whole-brain meta-analysis on surface-based morphometry studies between patients with SCZ and healthy controls by using the Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) software. The meta-analysis demonstrated that SCZ exhibits abnormalities in cortical thickness in the inferior frontal gyrus, insula, and superior temporal gyrus. The results expand the current understanding of cortical thickness abnormalities in patients with SCZ, which would provide promising targets for therapeutic intervention.
An analysis of longitudinal changes in dynamic brain activity with MHE patients treated initially with artificial livers: A follow-up fMRI study
Authors: Zheng Jiarui , Huang Xueying , Xiong Yuhui , Ma Wenfu , Wang Xiaodong
Published: August 2024

Artificial liver support is an increasingly important intermediate step in the treatment of patients with liver failure. Yet there is still a lack of imaging studies to evaluate the efficacy of artificial liver support (especially on cognitive function of MHE). This study sought to evaluate the temporal variability of ReHo in the brain spontaneous activity after artificial liver support and correlated it with the PHES. We found that the dReHo in the right superior frontal gyrus decreased and were negatively correlated with NCT-A and positively correlated with DST. Dynamic regional indexes might be a novel neuro-imaging biomarker for artificial liver efficacy evaluation.
Assessing the Effect of Selective Serotonin Reuptake Inhibitor on GABA and Neurometabolic Levels in the Brains of Violent Offenders: A Pilot Study
Authors: Al-iedani Oun , Brown-Miles James , Arm Jameen , Butler Tony , Luchow Shiami , Hillenbrand Claudia , Schofield Peter W , Ramadan Saadallah
Published: August 2024

Despite GABA implication in the regulation of aggression, the effects of selective serotonin reuptake inhibitor (SSRI) on GABA and Glx in an impulsive-aggressive population is yet to be explored. Seven repeat-offenders were treated with Sertraline and underwent MRI/MRS scans pre- and post-treatment (3-4 weeks of treatment). No significant changes (p≥0.05) in ACC-GABA+ or ACC-Glx were reported. Significant reduction in ACC-Glx/tCr (p=0.02) and increase in ACC-NAA (p=0.05) were found, while MM09+L09 increase approached significance (p=0.06). Further investigation is warranted. SSRIs clearly exert secondary effects on Glx levels in the ACC, with possible effects on NAA and MM09+L09.
Analysis of Deep Learning-based Reconstruction Models for Highly Accelerated MR Cholangiopancreatography: to Fine-tune or not to Fine-tune
Authors: Kim Jinho , Benkert Thomas , Riemenschneider Bruno , Nickel Marcel Dominik , Knoll Florian
Published: August 2024

MR cholangiopancreatography (MRCP) is a special MRI technique to visualize the biliary systems. Deep Learning-based (DL) reconstruction models have shown to reduce scan time from many anatomical regions. However, they generally require large training datasets. This is challenging for applications like MRCP, where public datasets are not available. This work analyzes two approaches to training a DL model for highly accelerated MRCP reconstruction: training from scratch using a small MRCP dataset and fine-tuning a model pretrained on a public knee dataset. Results show that despite of the substantial data domain shift between training and testing, fine-tuning outperformed training from scratch.
Reducing scan-time for 3D imaging with undersampled cartesian-radial phase encoding on a point-of-care 46 mT Halbach MRI scanner
Authors: Najac Chloé , Koolstra Kirsten , O’Reilly Tom , Webb Andrew
Published: August 2024

Low-field MRI systems (with B0<0.1T) for point-of-care applications are becoming increasingly widespread. Imaging at low-field remains challenging due to the low intrinsic SNR. We evaluated speeding up 3D imaging using radial-based Cartesian undersampled phase-encodings (PEs). In phantoms, we tested different undersampling schemes and compared them to full in-out Cartesian PE in terms of peak SNR (PSNR) to take account of spatial resolution and image SNR. Results suggests that a radial-based Cartesian PE trajectory with an overall acceleration factor of two can be implemented while preserving image quality (PSNR~69dB with R=2 vs. ~70dB with R=1.3 in a discrete spatial resolution phantom).
Differentiating patients with asthma and/or chronic obstructive pulmonary disease using lung T1 and M0
Authors: Hughes Paul , Marshall Helen , Smith Laurie , Jakymelen Demi , Biancardi Alberto , Collier Guilhem , Chan Ho-Fung , Brook Martin , Astley Joshua , Munro Ryan , Rajaram Smitha , Swift Andy , Capener David , Bray Jody , Ball James , Rodgers Oliver , Tahir Bilal , Rao Madhwesha , Norquay Graham , Weatherley Nicholas , Armstrong Leanne , Hardaker Latife , Fihn-Wikander Titti , Hughes Rod , Wild Jim
Published: August 2024

Directing treatment based on diagnosis is important in patients suffering with respiratory disease. This work investigated the ability of whole-lung mean T1 and M0, and measures of heterogeneity (median coefficient of variation and its interquartile range) to differentiate between patients with asthma and/or COPD and correlated these metrics with 129Xe ventilation and diffusion MRI and pulmonary function test metrics. Measures of heterogeneity of T1 and M0 correlated with lung function test outcomes and sensitive measures of lung function derived from 129Xe MRI and had the ability to separate patients with asthma+COPD and COPD from patients with asthma alone.
Fully automated 16- and 32-segmentation quantitative perfusion CMR in detection of obstructive coronary artery disease
Authors: Borodzicz-Jazdzyk Sonia , Hoek Roel , Vink Caitlin , Hopman Luuk , Hofman Mark , Somsen Yvemarie , de Winter Ruben , Knaapen Paul , Benovoy Mitchel , Gotte Marco
Published: August 2024

Recently, a fully automated QP CMR workflow has been established, which provides measures of stress MBF according to a 32-segmentation model with subdivision into endo- and epicardial subsegments. We compared the diagnostic accuracy of QP CMR according to the standard AHA 16-segment model (16M-QP) and the newly developed automated 32-segment model (32M-QP) with conventional visual assessment in patients who underwent adenosine stress perfusion CMR imaging followed by invasive coronary angiography and/or coronary computed tomography angiography. Our preliminary data have not shown superiority of diagnostic accuracy of 16M-QP or 32M-QP in comparison to visual assessment of adenosine stress first-pass perfusion imaging.
Based on cardiovascular magnetic resonance imaging for predicting right ventricular dysfunction in STEMI patients by Machine learning
Authors: Zhao Yanan , Cui Jianing , Yue Xiuzheng , Huang Sicong , Kang Yun , Li Tao
Published: August 2024

In clinical work, right ventricular (RV) dysfunction has been ignored in acute ST-Segment-Elevation myocardial infarction (STEMI) patients. And previous studies have shown the interaction between left ventricular (LV) and RV. The aim of this study was to assess RV function by cardiovascular magnetic resonance feature tracking (CMR-FT) and to explore what factors affect RV dysfunction by machine learning techniques. The results showed that the incidence of RV dysfunction was 32.28% in STEMI patients and the occurrence of RV dysfunction was associated with RV end-systolic volume index, LV ejection fraction (EF), and interventricular septum radial strain by machine learning technique.
Semi-automatic scar size quantification in late gadolinium enhancement of acute to chronic myocardial infarction in a porcine model scanned at 7T
Authors: Kollmann Alena , Lohr David , Bille Maya , Terekhov Maxim , Hock Michael , Elabyad Ibrahim , Schnitter Florian , Bauer Wolfgang , Hofmann Ulrich , Schreiber Laura
Published: August 2024

Late gadolinium enhancement (LGE) is considered the gold standard for the quantification of scar size. We tested in a large animal model of acute and chronic infarction if clinically used methods for the assessment of infarct size (manual planimetry and several semi-automatic approaches) in LGE images are applicable to preclinical 7T LGE imaging of porcine hearts. We found excellent intra-observer reproducibility for all methods. The tested semi-automatic methods performed differently on magnitude (MAG) and phase-sensitive inversion recovery (PSIR) images. Overall, infarct sizes measured in in vivo scans showed good correlation to ex vivo LGE measurements.
1H NMR of downfield metabolites in swine heart after myocardial infarction
Authors: Swago Sophia , Smothers Jacob , Wilson Neil , Elliott Mark , Nanga Ravi Prakash Reddy , Gorman Robert , Tschabrunn Cory , Sengupta Arjun , Weljie Aalim , Reddy Ravinder , Witschey Walter
Published: August 2024

Growing interest into in vivo 1H MRS of downfield metabolites (>4.7 ppm) has necessitated greater understanding of the metabolite contributions of peaks found in the downfield. 1H NMR provides high-SNR, high-spectral resolution data that can aid in the identification of metabolite resonances. We collected downfield NMR spectra at 700 MHz from infarct and remote myocardium extract of pig hearts after myocardial infarction. We were able to assign peaks to NAD+, NADH, ATP, and AMP in the downfield region and quantified these metabolites in infarct and remote myocardium.
Association between HFpEF and Impaired Left Heart strain in Hypertensive Heart Disease: Evaluation by Cardiac MRI Feature Tracking
Authors: Ke Tianyu , Mu Xiaolin , Chen Jing , Song Yang
Published: August 2024

The application value of left atrial and left ventricular strain parameters to heart failure with preserved left ventricular ejection fraction in hypertensive heart disease was evaluated by cardiac magnetic resonance feature tracking technology. We found that the left atrial function, strain, and left ventricular strain parameters were impaired to varying degrees in the HFpEF-HHD group, and the left atrial ejection fraction was significantly correlated with some feature parameters of left atrial and left ventricular strain. However, NT-proBNP is only significantly correlated with LAεa. In the identification of the HFpEF-HHD population, the LASRe parameter has shown optimal diagnostic value.
Cardiac MRI left ventricular and left atrial parameters predict myocardial late gadolinium enhancement in hypertrophic cardiomyopathy
Authors: Tian Di , Xiong Ziqi , He Yifan , Zhang Jingyu , Li Zhiyong
Published: August 2024

Myocardial fibrosis causes functional impairment in patients with hypertrophic cardiomyopathy (HCM). The clinical gold standard for imaging myocardial fibrosis is cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE), which is commonly used for the diagnosis and prognostic evaluation of patients with HCM. However, LGE imaging is an invasive test and some patients have adverse reactions to contrast agents. The aim of this study is to predict the presence of fibrosis in the left ventricular myocardium by cardiac magnetic resonance (CMR) non-invasive assessment of left atrial and left ventricular parameters in patients with HCM.
Left ventricular layer-specific strain predicts pulmonary arterial hypertension long-term prognosis
Authors: Li Wen , Zhang Xianchang , Wetzl Jens , Gu Qing , He Jianguo
Published: August 2024

Studies have reported left ventricular (LV) dysfunction was associated with more severe disease and poorer prognosis in pulmonary arterial hypertension (PAH). However, there are only few studies that evaluated LV strain abnormalities using cardiovascular magnetic resonance (CMR) in PAH patients. This is the first study to describe the distribution pattern and prognostic values of LV layer-specific strain/strain rate in PAH patients using a deformation registration algorithm (DRA) based on CMR. It’s found that CMR derived LV layer-specific strain could predict long-term prognosis in PAH patients.
Resting perfusion measures in patients with steno-occlusive disease; comparing two contrast agents Gadolinium and hypoxia-induced dOHb
Authors: Sayin Ece Su , Stumpo Vittorio , Bellomo Jacopo , Poublanc Julien , Piccirelli Marco , Duffin James , Wijeya Vepeson , Pangalu Athina , Bink Andrea , Nemeth Bence , Kulcsar Zsolt , Mikulis David , Fisher Joseph , Sobcyzk Olivia , Fierstra Jorn
Published: August 2024

Dynamic susceptibility contrast perfusion imaging is clinically acquired using Gadolinium based contrast agents (GBCA), however, there remain many drawbacks. We show that in patients with steno-occlusive disease perfusion imaging using hypoxia-induced dOHb have a high degree of similarity to those obtained using GBCA.
Relaxometry Measurements of Europium-doped Mn0.6Zn0.4Fe2O4 at Increasing Magnetic Field
Authors: saeidi Hamidreza , Mozaffari Morteza , Ilbey Serhat , Leupold Jochen , Bock Michael
Published: August 2024

Magnetic resonance imaging (MRI) contrast agents with both intrinsic high r1 and r2 relaxivities are desirable in medical diagnosis to achieve highly accurate and ambiguity-free MR images. Here, we report synthesis and MRI tests of Europium doped Mn-Zn ferrite (EuMZF) nanoparticles at different magnetic field strengths. EuMZF nanoparticles showed significant improvement in both positive (T1) and negative (T2) contrasts. The results showed that by increasing magnetic field, r1 relaxivity decreased while r2 increased so that the EuMZF is suitable as a dual-mode contrast at 1.5 and 3T but it is a T2 agent at 7 and 9.4T.
Molecular Weight of Sugar Structures impacts Shielding Effect of Gd-Ions in Polysaccharides.
Authors: Werner Patrick , Taupitz Matthias , Ber Sophia , Schröder Leif
Published: August 2024

Detailed biochemical information on the long-term deposition of Gd3+ in the body after administration of GBCAs is still missing. Glycosaminoglycans should be considered as chelators of released Gd3+. We used dextran-sulfate to study the effect of polysaccharides with different molecular weights on the observable relaxivity. Chelation was observed through an increase in relaxation. Moreover, a molecular weight-specific shielding revealed by subsequent reduced R1 occurs at higher polysaccharide/Gd-ion ratios. This coincided with observations of Gd-induced aggregation. Similar shielding of re-chelated Gd3+can lead to an underestimation of deposited Gd-ions in the body and requires further research.
Robust in vivo MRI of OATP reporter gene expressing cells using standard clinical dose of MRI contrast agent
Authors: Bhattacharyya Tapas , Hix Jeremy , Mallett Christiane , Shapiro Erik
Published: August 2024

Hepatic OATPs are a promising molecular imaging reporter gene for MRI yet its translation for human studies is limited by the reported extremely high dose of contrast agent required (>40x clinical dose) for robust detection of engineered cells in vivo. Here we describe studies that culminated in the in vivo MRI detection of OATP-overexpressing cells using standard clinical doses. OATP-overexpression was accomplished by lentiviral transduction of tumor cells, followed by MRI screening to determine the best performing OATPs. In vivo MRI of OATP-overexpressing tumors was accomplished using a combination of both T1-weighted and dynamic contrast enhanced (DCE-) MRI.
Relaxation Rate MR Contrast of Metal-Organic Framework or USPIO Labelled Melt Electrowritten Polycaprolactone Scaffolds
Authors: Topping Geoffrey , Mansi Salma , Müller Kilian , Hussain Zahid , Dummert Sarah , Rickert Carolin , Schwaminger Sebastian , Zou Younzhe , Rojas-González Diana , Berensmeier Sonja , Lieleg Oliver , Fischer Roland , Mela Petra , Schilling Franz
Published: August 2024

Polycaprolactone scaffolds were melt electrowritten with and without included metal-organic frameworks (MOF) or nanoparticles (USPIO). MR images and relaxation rate (R1, R2, R2*) maps were acquired of scaffolds in agar and blood. Pure polycaprolactone showed weak or no contrast. Addition of MOF or USPIOs produced strong T2* contrast. Tensile properties were preserved up to 0.2 w/w% USPIOs. MOFs produced strong w/w% dependent antibacterial effects when included in scaffolds.
High Longitudinal and Transverse Relaxivities with Rare Earth ions doped Mn0.6Zn0.4Fe2O4: a Potential for dual-mode Contrast Agents
Authors: saeidi Hamidreza , Mozaffari Morteza , Ilbey Serhat , Bock Michael
Published: August 2024

MRI contrast agents have gained extensive attention for providing contrast between normal and abnormal tissue. However, single-mode contrast agents do not always provide the required contrast enhancement for disease detection. One effective strategy for avoiding ambiguous images is to design MRI contrast agents with simultaneous T1 and T2 shortening effects. The purpose of this work is to synthesize rare earth ions doped Mn-Zn ferrite (ReMZF) nanoparticles and characterize them with a 1.5T MRI scanner in vitro. The ReMZF exhibited high r1 and r2 relaxivities but moderate r2/r1 which make them suitable to be used as dual-mode contrast agents.
A dedicated arterial input function compensating for inflow and partial voluming in dynamic contrast enhanced MRI
Authors: Tseng Chih-Hsien , Nagtegaal Martijn , Jaspers Jaap , Romero Alejandra Mendez , Wielopolski Piotr , Smits Marion , van Osch Matthias , Vos Frans
Published: August 2024

Both inflow and partial volume effects (PVE) are sources of error when measuring the arterial input function (AIF) in DCE-MRI. We proposed a method that estimated the perceived pulse number of spins, and then corrected with these such that both effects were simultaneously compensated. Simulation data demonstrated that the reconstructed AIFs showed only marginal bias. In addition, the algorithm yielded highly correlated reconstructed curves over a wide range of PVEs in clinical data. Our findings show that the PVE can be compensated by considering it as part of the inflow correction as it exhibits similar confounding effects when measuring DCE-AIFs.
Sampling Time Considerations for T1 map acquisition on the 64mT Hyperfine Swoop system: A Phantom Evaluation Study
Authors: Nguyen Vivian , Ragunathan Sudarshan , Carroll Timothy , Javed Adil , Vaicik Marcella , Georgiadis John , Kawaji Keigo
Published: August 2024

T1 maps provide quantitative relaxometric measures of tissue responses that may carry correlative indices of specific disease indications. On the recently commercialized 64mT system (Hyperfine Inc.), little has been reported regarding both clinical T1 relaxometric normal values in presence of Gadolinium-based contrast and relevant acquisition schemes with Gd contrast enhancement. In this study, we examine an array of Gadolinium-doped vials that represent 10-5000 fold dilution in the vasculature using an Inversion-Recovery FSE acquisition to gain key insights on: a) anticipated normal values in presence of Gd, b) conventional fitting algorithm performance, and c) potential inferences on inversion timing selection.
Quantitative Assessment of the Whole Spine in T2 MRI Using Deep Learning
Authors: Khallaghi Siavash , Porto Lucas , London Sean , Chodakiewitz Yosef , Attariwal Rajpaul , Hashemi Sam
Published: August 2024

We present a fully automatic system for the quantitative assessment of discs and vertebrae using convolutional neural networks. The proposed algorithm works in three stages: 1) segmentation/identification of spinal anatomy; 2) curvature analysis; and 3) detection of pathological conditions of intervertebral discs. We validate the proposed approach on a large dataset of 1,500 subjects with sagittal T2-weighted whole spine MRI, obtained as part of a whole body MRI protocol in a preventative health screening program.
An unsupervised deep learning-based method for in vivo high resolution Kidney MRI motion correction
Authors: Moinian Shahrzad , Kurniawan Nyoman , Chandra Shekhar , Vegh Viktor , Reutens David
Published: August 2024

A primary challenge for in vivo kidney MRI is the presence of different types of involuntary physiological motion, affecting the diagnostic utility of acquired images due to severe motion artifacts. Existing prospective and retrospective motion correction methods remain ineffective when dealing with complex large amplitude nonrigid motion artifacts. We introduce an unsupervised deep learning-based method for in vivo kidney MRI motion correction. We demonstrate that our deep learning model achieved the average structural similarity index measure (SSIM) of 0.76±0.06 between the reconstructed motion-corrected and ground truth motion-free images, showing an improvement of about 0.33 compared to the corresponding motion-corrupted images.
Deep learning based estimation of patient anthropometric data for intelligent scan planning in MR
Authors: Kumar Subham , Rai Harikrishna
Published: August 2024

Estimating patient height and weight is used to determine the optimum SAR (Signal Modelling) for the patient. We used a deep learning approach to first generate the point cloud of the person (Data Processing) followed by prediction of the height and weight (Data Analysis). This tackles the problems of heavy occlusion which occurs in the MR imaging scenario in the form of coils/blankets and different positions in which the patient will be placed. We achieved a MAE score of 4.9 cm on the height and 6.2 kg on the weight. This is a promising solution to an important problem.
Analysis of Dynamic Network Reconfiguration in First-Episode, Drug-Naive Patients with Major Depressive Disorder Based Multilayer Network
Authors: Wang Yingying , Tang Mengyue , Zhou Zilin , Gao Yingxue , Cao Linxiao , Li Hailong , Hu Xinyue , Bao Weijie , Liang Kaili , Zhang Lianqing , Kuang Weihong , Gong Qiyong , Huang Xiaoqi
Published: August 2024

We collected resting-state fMRI data from 115 patients with major depressive disorder (MDD) and 120 healthy controls (HC). The GenLouvain community detection algorithm was performed to identify the temporal evolution of community in the multilayer network. Recruitment and integration coefficients were calculated according to the module allegiance matrix to quantify the dynamic characteristic of a node within each of the networks. We found aberrant recruitment and integration coefficients in MDD patients and their significant correlations with clinical scores, and such abnormally dynamic network reconfiguration provides a new perspective to explain the neurobiological characteristics of MDD patients.
Complex-Valued Fourier Primal-Dual: Undersampled MRI Reconstruction in Hybrid-space
Authors: Chatterjee Soumick , Ernst Philipp , Speck Oliver , Nürnberger Andreas
Published: August 2024

Iterative undersampled MRI reconstructions, such as compressed sensing, can reconstruct undersampled MRIs - but due to their slow execution speed, they are not suitable for real-time applications. Several deep learning approaches have been proposed, mostly working in image space. Some of the approaches, which work on the k-space or in a mix of spaces, employ real-valued convolutions splitting the complex k-space into real and imaginary parts for processing - destroying the geometric relationship within the data. This research proposes Fourier-PD and Fourier-PDUNet models using complex-valued convolutions, which attempt to predict missing k-space frequencies and also to reduce artefacts in the image space.
Model-based phase-difference reconstruction for accelerated phase-based T2 mapping
Authors: Wang Xiaoqing , Cho Jaejin , Jun Yohan , Gagoski Borjan , Bilgic Berkin
Published: August 2024

Phase-based T2 mapping acquires two GRE volumes with opposite RF phase increments, then computes the phase difference and relates this to T2 values through Bloch modeling. We exploit the redundancy in these two acquisitions by posing this as a nonlinear inverse problem, and directly estimate the phase difference from k-space. This reduces the problem to the estimation of a complex M0 volume, and a real-valued phase difference, thus reducing the number of real-valued unknowns from 4 to 3 per voxel. The proposed reconstruction flexibly admits additional regularization, and yields higher quality images from undersampled acquisitions for rapid T2 mapping.