bluuebunny/crossref_metadata_2025 huggingface dataset:
Single-offset and multi-offset super-resolution for CEST MRI using deep transfer learning
Authors: Prabakaran Rohith Saai Pemmasani , Chen Zilin , Lai Joseph H.C. , Park Se Weon , Liu Yang , Huang Jianpan , Chan Kannie W.Y.
Published: August 2023

CEST MRI is an unique molecular imaging approach to reveal the exchangeable proton information related to physiology and pathology. However, long scanning time has hindered its translation into clinics. While deep-learning based super-resolution methods have been explored to reduce scanning time in conventional MRI, adaptation of these methods to CEST MRI has been limited due to lack of large public CEST datasets. Therefore, this study proposes two transfer learning based super-resolution methods, Single-Offset UNet and Multi-Offset UNet, for accelerating CEST MRI acquisition by using public MRI databases for pretraining and a very small CEST dataset for training.
Characterization and correction of the hepatic iron effects on T1rho relaxation in the liver at 3.0 Tesla
Authors: QIAN Yurui , Hou Jian , Jiang Baiyan , Wong Vincent , Chan Queenie , Wang Yixiang , Chu Winnie , Chen Weitian
Published: August 2023

Spin-lock T1rho is a non-invasive MR imaging method. It has the potentials for the assessment of chronic liver diseases. However, liver iron content can potentially confound T1rho quantification of the liver. In this work, we reported a method to correct the influence of liver iron content on T1rho quantification of the liver at 3.0T.
Prediction of IDH, 1p/19q and TERTp Status: combination of APTw value of tumor solid and peritumoral area
Authors: Ren Xinying , Xiong Diaohan , Gan Tiejun , Wang Pengfei , Wang Rui , Wen Tao , Li Yujing , Zhang Jing , Ai Kai
Published: August 2023

This study aims to analyze the metabolic information in both tumor solid and peritumoral area of gliomas to predict its genotype by using Amide Proton Transfer weighted (APTw) imaging. As a complementary method of pathological evaluation, APTw based MRI technique could provide a prediction of the gliomas genotype. Unlike other studies focus on tumor core region, our research investigated the APTmean value of tumor solid and the peritumoral area. Interestingly, the results showed that the AUC value of peritumoral area was higher than the tumor solid. The APTw images may serve as a potential marker for the genotyping of gliomas.
Resolution phantoms for MR microimaging with 4µm≤ps≤256µm based on anisotropic tube channels (PSF + MTF) fabricated by Deep X-Ray-Lithography
Authors: Berg Andreas , Börner Martin
Published: August 2023

The most important quality control criterions in Magnetic Resonance Imaging (MRI) are represented by the contrast-to-noise-ratio (CNR) and the spatial resolution. This report presents the design, a prototype object, an exemplary MRI evaluation, qualitative results and quantitation of the spatial resolution up to microscopic scale beyond pixel-size characterization. The phantom is manufactured using Deep X-Ray Lithography (DXRL) at the Synchrotron radiation source KARA (Karlsruhe Research Accelerator) for obtaining highly anisotropic tube type cavities for getting the Point-Spread-Function (PSF) and Modulation Transfer Function (MTF) in MR-µ-imaging ranging from d=256µm down to d≈4 µm.
An Innovative MRI phantom Allowing Evaluation of the Influence of Fat Fraction on the Measurement of ADC under Different Glass Bead Densities
Authors: Peng Jo-Hua , Juan Chun-Jung , Liu Yi-Jui , Chou Ruey-Hwang , Chang Hing-Chiu , Liou Chang-Hsien , Chou Szu-Hsien , Wu Yen-Ting , Wu Bai-Wen , Peng Hsu-Hsia
Published: August 2023

Although a single-function phantom for either ADC or fat content is popular, it is crucial to develop a multiple-function phantom to simulate the real situation of human tissue in vivo. The aim of our study was to design a novel phantom containing different fat fractions and cellularity to evaluate the effect of fat content on ADC measurement in vivo as in human tissue environment. In conclusion, the influence of fat contents and glass beads density on ADC values was examined in our dual-function phantom, which can be helpful to improve the accuracy of ADC quantification in clinical practice.
Miniaturized and Reproducible Phase Shifters using Capacitor-Loaded Transmission Lines for Add-On RF Shimming at High Field
Authors: Lu Ming , Zhu Yue , Gore John , Grissom William , Yan Xinqiang
Published: August 2023

Add-on RF shimming devices, including phase shifters, could provide additional degrees of freedom for RF transmit chains to improve field uniformity and reduce SAR. At the Larmor frequencies of MRI, however, the transmission line length for realizing large phase shifts becomes unrealistically long. We introduce a capacitor-loaded transmission line design to build a miniaturized microstrip line phase shifter for RF shimming at high fields. The fabricated phase shift boards had a miniaturized size of 3 x 4 cm2, exhibited a low loss of < 0.26 dB, and cost much less than those made from other materials.
A Balanced RF Switch for Ultra-Wideband System with Microsecond Dead Time
Authors: Xu JunCheng , Yao Shouquan , Shen Ming , Song Yiqiao , Jiang Yu , Li Jianqi
Published: August 2023

This work demonstrated a fully balanced strcture of wideband RF switch. The switch utilizes PIN diodes to form two balanced paths which transmit the RF signals in common mode and the drive signal of PIN diode in differential mode.The common-mode choke can be used to block AC signal and feed DC bias. It can also be used to suppress the transient voltage due to the drive signal. The switch achieved low insertion loss and high isolation within a bandwidth between 10MHz-100MHz. The switch also suppressed the transient voltage to less than 3.3mV with a very short dead time.
Probing evidence of brain macrostructural disruptions in coronary artery disease: A diffusion MRI tractometry study
Authors: Poirier Stefan , Suskin Neville , Lawrence Keith St. , McIntyre Christopher , Thiessen Jonathan , Shoemaker J. , Anazodo Udunna
Published: August 2023

White matter (WM) breakdown is linked to cognitive impairment in coronary artery disease (CAD). We used diffusion MRI tractometry to assess the effects of cardiac disease, brain aging, and cardiac rehabilitation (CR) on regional WM macrostructure in brains of CAD patients. WM disruptions were found in CAD patients at baseline (pre-CR) compared to controls and in old controls compared to young controls. WM improvements, especially in regions linked to cognition, were observed in CAD patients following CR. Both cardiac disease and brain aging may contribute to WM dysfunction in CAD, and these WM disruptions may be favourably modified by CR.
A fixel-based analysis of white matter alterations in patients with acute mild traumatic brain injury
Authors: Jiang Li , Zhuo Jiachen , Roys Steven , Tchoquessi Rosy Linda Njonkou , Gullapalli Rao
Published: August 2023

Mild traumatic brain injury (mTBI) accounts for the majority of head injuries and is often associated with physical, cognitive, and effective deficits. We used fixel-based analysis (FBA) to investigate the white matter (WM) structural alterations in acute mTBI patients. Three fixel-based metrics were used: fibre density (FD), fibre-bundle cross-section area (FC) and a combination of FD and FC (FDC). We found out that mTBI patients demonstrated reduced FC and FDC in multiple WM tracts and it may suggest that FBA can be used to detect subtle WM changes following mild injuries.
Longitudinal Assessment of Tumor Perfusion in Glioblastoma using Arterial Spin Labeled MRI: Preliminary Findings
Authors: Wang Yiming , Pinho Marco , Zhou Limin , Youssef Michael , Maldjian Joseph , Madhuranthakam Ananth
Published: August 2023

In Glioblastoma (GBM) patients undergoing chemoradiation, decreased tumor perfusion can be observed in treatment-responding patients and earlier than changes in tumor volume measured by conventional MRI. Such perfusion changes can be measured by non-contrast Arterial Spin Labeled (ASL) MRI, which is particularly suitable for longitudinal assessment of tumor perfusion. In this study, we performed longitudinal perfusion measurements using ASL MRI in patients with glioblastoma undergoing chemoradiation. Progressive perfusion reduction was observed in a representative patient's enhancing tumor ROIs along with increased ADC values, indicating reduced tumor cellularity, which likely results from treatment responses.
Phase-Sweep Method and Fitting Analysis in Slow CSF Shunt Flow Measurement with PS-FENSI
Authors: Zhang Mingxiao , Anderson Aaron , Arnold Paul , Huston Jason , Olivero William , Sutton Bradley
Published: August 2023

Pediatric patients with hydrocephalus rely on ventriculo-peritoneal shunts to drain cerebrospinal fluid (CSF) from the brain. Quick, safe detection of shunt failure is crucial to preventing neurologic injury. Previously, a non-invasive MRI-based monitoring technique, Shunt Flow Enhancement of Signal Intensity (Shunt-FENSI), was proposed for accurate and quantitative CSF flow measurement in the slow flowing shunt. We are introducing a more advanced version, Phase-Sweep FENSI (PS-FENSI) to deal with magnetic field inhomogeneity which can cause changes to the tag effectiveness. This new method is accompanied by new fitting methods to more reliably measure FENSI signals.
Subcutaneous adipose tissue water fraction increases with weight loss in persons with obesity
Authors: Han Jessie , Wu Mingming , Rupp Selina , Junker Daniela , Reik Anna , Wiechert Meike , Hauner Hans , Makowski Marcus , Holzapfel Christina , Ruschke Stefan , Karampinos Dimitrios
Published: August 2023

Subcutaneous adipose tissue (SAT) dysfunction is key in defining high-risk individuals in obesity. A change in adipose tissue water fraction with weight loss may reflect improvement in blood flow or changes in microstructure of adipose tissue. Single-voxel STEAM Magnetic Resonance Spectroscopy (MRS) and chemical shift encoded-based water-fat separation are non-invasive methods to assess the water fraction and proton density fat fraction (PDFF) of adipose tissue. The present work aims to investigate the feasibility of MRS and water-fat separation to quantify PDFF and evaluate the changes in SAT water fraction in persons with obesity undergoing an 8-week weight loss intervention.
Detection and prediction of background parenchymal enhancement on breast MRI using deep learning
Authors: Das Badhan Kumar , Kapsner Lorenz A. , Ohlmeyer Sabine , Laun Frederik B. , Maier Andreas , Uder Michael , Wenkel Evelyn , Bickelhaupt Sebastian , Liebert Andrzej
Published: August 2023

The purpose of this work was to automatically classify BPE using T1-weighted subtraction volumes and diffusion-weighted imaging volumes in breast MRI. The dataset consisted of 621 routine breast MRI examination acquired at University Hospital Erlangen. 2D MIP and 3D T1-subtraction volumes were used for the automatic detection of BPE classes. Multi-b-value DWI (up to1500s/mm2) DWI images were used for automatic prediction. ResNet and DenseNet models were used for 2D and 3D data respectively. The study demonstrated an AUROC of 0.8107 on the test set using the T1-subtraction volumes. With DWI volumes, a slightly decreased AuROC of 0.78 was achieved.
A Free-Breathing Hybrid Technique for Simultaneous T2w, T1w, PDFF, and R2* Imaging at 0.55T
Authors: Keerthivasan Mahesh , Bruno Mary , Solomon Eddy , Benkert Thomas , Grodzki David , Bhat Himanshu , Block Kai Tobias , Chandarana Hersh
Published: August 2023

Recently, there has been renewed interest in imaging at low field strengths. The increased T2* relaxation times at 0.55T and reduced chemical shift between fat and water requires the need for longer TEs for accurate fat fraction and R2* estimation, often resulting in longer acquisition times. In this work, we present a scan-efficient hybrid TSE-GRE technique for the simultaneous acquisition of T2- and T1-weighted images along with quantification of fat fraction and R2*. The use of a stack-of-stars trajectory allows SNR efficient free breathing imaging at 0.55T.
Development of in vivo human brain DTI-MRE: Preliminary results
Authors: Lin Shujun , Sutton Brad , Magin Richard , Anderson Aaron , Klatt Dieter
Published: August 2023

Simultaneous acquisition of diffusion tensor imaging (DTI) and magnetic resonance elastography (MRE) has been proven feasible in a pre-clinical study and in preliminary studies of in vivo human brain. However, the experimental parameters have to be optimized in order to prevent mutual interferences of DTI and MRE acquisitions. We identified in simulations two experimental parameter sets for in vivo human brain DTI-MRE that we classify as good and moderate and present a pilot study using these parameter sets. The experimental results indicate that both experimental parameter sets show good performance using motion-encoding gradients without flow compensation.
Accelerated Simultaneous T2 and T2* Mapping of Multiple Sclerosis Lesions Using Compressed Sensing Reconstruction of 2in1-RARE-EPI Data
Authors: Herrmann Carl , Starke Ludger , Millward Jason , Paul Friedemann , Kuchling Joseph , Niendorf Thoralf
Published: August 2023

We previously applied a radially-sampled RARE-EPI hybrid for simultaneous T2 and T2* mapping (2in1-RARE-EPI) in patients with multiple sclerosis, which reduced the scan time to 77% compared to Multi-Spin-Echo (MSE) and Multi-Gradient-Recalled-Echo (MGRE). Here we examine the potential for further acceleration utilizing a compressed sensing reconstruction of highly undersampled 2in1-RARE-EPI data. The accelerated T2 and T2* mapping is benchmarked against the MSE and MGRE references using regression and Bland-Altman plot analysis and the mean absolute percentage error. Our results show that an undersampling factor of 8-12 is feasible, achieving an acquisition time reduction to 23-17% compared to the references.
iMPI – first real-time imaging with a human-sized interventional Magnetic Particle Imaging scanner
Authors: Vogel Patrick , Rückert Martin , Reichl Teresa , Günther Johanna , Greiner Christoph , Mirzojan Liana , von Böhn Alexander , Kampf Thomas , Bley Thorsten , Behr Volker , Herz Stefan
Published: August 2023

In this work a first human-sized Magnetic Particle Imaging (MPI) scanner designed and specifically engineered for experimental (cardio)vascular interventions is presented.

Based on a novel open design implementing the so called traveling wave MPI approach, the open iMPI system provides imaging of Tracers based on superparamagnetic iron oxide nanoparticles (SPIONs) with high sensitivity, optimal patient handling and would even allow hybrid imaging of magnetic tracers within gold standard x-ray based interventional angiography systems.

In initial experiments, the feasibility of a human-sized interventional MPI scanner with real-time data reconstruction and image visualization is demonstrated.
8ch multi transmit with ultrasonic dual axis gradient and 32ch receive setup for fast spatial encoding at 7T
Authors: Gosselink Mark , Ieperen Aris , Schuth Wout , Borgo Martino , Welting Dimitri , Versteeg Edwin , Klomp Dennis
Published: August 2023

We propose a setup to boost spatiotemporal encoding for MRI in the human brain using a conventional receiver array (32ch) and fast gradients (6100T/m/s). Moreover, we demonstrate that the operation frequency of a high-end gradient-amplifier can be increased to ultrasonic frequencies so to avoid unpleasant acoustic noise. By using this amplifier with 8 RF transmitters, 32 receivers and a 2-channel gradient coil, a light-weight setup is constructed for operation in a 7 Tesla MRI system. The setup is demonstrated for operation in the human brain showing good FLAIR data and no peripheral nerve stimulation at the slew rate of 6100T/m/s.
Measuring stroke volume with wearable RF antennas: a validation study with EM simulations and MRI
Authors: Steensma Bart , Louka Christina , Raaijmakers Alexander , van den Berg Cornelis
Published: August 2023

We developed a wearable setup to detect heart motion and stroke volume with an RF antenna connected to a miniature network analyzer. EM simulations were used to demonstrate the possibility of measuring changes in stroke volume with an RF antenna and to investigate the spatial sensitivity of the antenna. A Valsalva manoeuver was used to provoke changes in stroke volume, which were observed with the RF antenna and in cine MRI acquisitions.
A modern machine-learning approach to reveal the role of multiple sclerosis lesions in inducing cortical tissue loss
Authors: Treaba Constantina , Conti Allegra , Mehndiratta Ambica , Barletta Valeria , Mainero Caterina , Toschi Nicola
Published: August 2023

In multiple sclerosis (MS), cortical atrophy could result from extensive axonal transection from distant white matter lesion and/or local cortical demyelination. The destructive potential of MS white matter lesions, however, seem to differ across lesion types, being higher for chronic active lesions detectable on susceptibility weighted images by their characteristic paramagnetic rim. Using 7T MRI that has shown increased sensitivity to cortical lesions and modern machine learning algorithms, we demonstrate that both white matter and cortical lesions are main determinants of cortical thinning. Despite their destructive capacity, chronic active lesions are not major contributors of cortical tissue loss.
White matter inflammation and its relation to myelin content in vivo in patients at different stages of multiple sclerosis.
Authors: Barletta Valeria , Herranz Elena , Treaba Constantina , Mehndiratta Ambica , Ouellette Russell , Granberg Tobias , Klawiter Eric , Ionete Carolina , Sloane Jacob , Mainero Caterina
Published: August 2023

We combined 11C-PBR28 magnetic resonance-positron emission tomography, marking activated microglia, with synthetic MRI to measure myelin content, on a group of 33 patients affected by multiple sclerosis, to quantify neuroinflammation in the brain white matter and assess its relation to myelin content and disease burden. Microglia activation was higher in the white matter of multiple sclerosis patients compared to 16 healthy volunteers. Microglia activation within perilesional WM correlated the most with worse disease outcomes. Peripherally active lesions were related to higher disability and progressive disease. Perilesional myelin content was lower for higher inflammation and correlated with disease burden.
Initial in vivo evidence of fibrin deposition in multiple sclerosis patients using fibrin-targeted 64Cu-FBP8 positron emission tomography
Authors: Treaba Constantina , Catana Ciprian , Klawiter Eric , Huang Susie , Arabasz Grae , Barletta Valeria , Herranz Elena , Sloane Jacob , Caravan Peter , Mainero Caterina
Published: August 2023

In multiple sclerosis, experimental and histopathological studies point to fibrinogen as a link between a damaged brain blood barrier and the initiation of the inflammatory demyelination and neurodegeneration in both cortex and white matter. Nevertheless, although the widespread accumulation of fibrinogen as fibrin deposits within multiple sclerosis lesions is well documented on postmortem brain tissue, in vivo evidence is still lacking. Using a novel fibrin-specific positron emission tomography probe, 64Cu-FBP8, we were able to demonstrate in vivo fibrin deposition not only in active white matter multiple sclerosis lesions but also in the cortex of a few multiple sclerosis patients.
Preoperative 7T MRI relates to medication dose reduction after chronic deep brain stimulation for Parkinson’s disease
Authors: Khanna Sharmaine , Johnson Amirah , Lyons Isyss , Sipes Ben , Tymofiyeva Olga , Lupo Janine , Ostrem Jill , Wang Doris , Starr Philip , Bledsoe Ian , Morrison Melanie
Published: August 2023

Robust objective markers that can predict an individual Parkinson’s disease (PD) patient's potential response to brain stimulation (DBS) are limited. Here we evaluate the relationship between preoperative multimodal 7T MR metrics and a surrogate measure of motor response to DBS: the pre-to-post change in daily dose of dopamine medications. We found that fMRI signal variability in the superior sensorimotor network was more strongly correlated with medication dose reduction after DBS than current clinical prognostic criteria. Brain iron accumulation in the globus pallidus interna furthermore discriminated patients who did versus did not experience a dose change.
Texture analysis of clinical MRI detects characteristics of tissue repair in lesions of multiple sclerosis after treatment with domperidone
Authors: Hosseinpour Zahra , Oladosu Olayinka , Soleymani Mahshid , Liu Wei-qiao , Pike G Bruce , Koch Marcus , Yong V. Wee , Metz Luanne , Zhang Yunyan
Published: August 2023

MS pathology is dynamic, involving damage and repair. We used statistical texture analysis to assess changes in MS lesions seen in sequential brain MRI of 16 RRMS patients after treatment with domperidone. We focused on 2 histology-verified texture measures: contrast and dissimilarity, which characterize tissue coarseness and heterogeneity, respectively. Lower contrast and dissimilarity were detected in both acute and total lesion groups at weeks 16 and 32 compared to baseline, and at week 32 compared to week 16. The observed changes in texture suggest remyelination in MS lesions following treatment.
Higher functional activity in the somatomotor network is associated with functional reorganization in the early stage of multiple sclerosis
Authors: Tozlu Ceren , Card Sophie , Jamison Keith , Gauthier Susan , Kuceyeski Amy
Published: August 2023

Multiple Sclerosis (MS) is a disease that causes neuroinflammation and neurodegeneration in central nervous system. Neuroimaging techniques may enable us to better understand the neuropathological mechanisms of MS and how the brain may compensate the pathological changes. We identified the recurring dynamic brain states using fMRI data and investigated the energy required for the transition between those states using the network control theory approach. Our main findings are the dynamic states were visual, somatomotor, and frontoparietal states and the transition energy averaged over all transitions was significantly greater in the MS patients with disability compared to those without disability.
Differences in functional connectivity in older adults with mild cognitive impairment and subjective cognitive decline
Authors: Srikanthanathan Arunan , Vandermorris Susan , Verhoeff Nicolaas , Chen Jean , Herrmann Nathan , Mah Linda
Published: August 2023

Subjective cognitive decline (SCD) is a preclinical stage of Alzheimer’s disease (AD) that may precede mild cognitive impairment (MCI), a prodrome of AD. We used resting-state functional magnetic resonance imaging to examine the pattern of functional connectivity in anterior brain regions that support memory processes in SCD and MCI. We found reduction of posterior cingulate cortex functional connectivity with medial temporal lobe structures in MCI and SCD, and associated increases in functional connectivity in the anterior brain regions, although direct group comparisons of the latter did not yield statistically significant differences.
Mapping of Early-Stage Changes in Cerebral Glutamate in APPNL-F/NL-F Mouse Model of Alzheimer’s Disease Using GluCEST MRI
Authors: Soni Narayan Datt , Nanga Ravi Prakash Reddy , Halvor Juul , Reddy Ravinder
Published: August 2023

Alzheimer’s disease (AD) is characterized by progressive loss of cognitive abilities. Glutamate being the major excitatory neurotransmitter in mammalian brain, regulates various cognitive functions. Reports suggesting compromised cerebral glutamate homeostasis in AD indicates the potential of glutamate mapping in early diagnosis of AD. In the current study, we have used glutamate weighted Chemical Exchange Saturation Transfer (GluCEST) MRI to investigate changes in cerebral glutamate in 6-month-old APPNL-F/NL-F mouse model of AD. Our findings suggest reductions in the levels of cortical and hippocampal glutamate in APPNL-F/NL-F mice. A longitudinal study is ongoing to understand the pattern of perturbation with disease progression.
Hippocampal Glx in RRMS: A potential therapeutic indicator in fingolimod and injectables
Authors: Al-iedani Oun , Lea Rodney , Arm Jameen , Ramadan Saadallah , Lechner-Scott Jeannette
Published: August 2023

This novel longitudinal study evaluates the hippocampal metabolic and morphologic effects of different DMTs on the RRMS brain. RRMS patients were on fingolimod(N=36), injectables(N=29) and HCs cohort(N=44). MRS was acquired from hippocampus. Findings revealed that fingolimod is associated with a larger statistically significant reduction in hippocampal Glx (p=0.003) compared to injectable (p=0.01) and trending lower compared to HCs (p=0.09). Hippocampal NAA levels showed statistically significant increase in the fingolimod cohort (p≤0.0001) compared to HCs over the 2-years follow-up. These results demonstrate that fingolimod has a more potent effect on hippocampal Glx and NAA profiles than injectable DMTs.
Whole-lesion ADC histogram and texture analysis of preoperatively differentiating benign endometrial lesions from stage IA endometrial cancer
Authors: Zhang Jieying , Yu Xiaoduo , Chen Shuang , Xie Lizhi , Chen Yan , Ouyang Han
Published: August 2023

Making an accurate preoperative diagnosis of endometrial lesions is critical to avoid unnecessary surgical procedures and protect the patients’ fertility. Noninvasive pre-surgical evaluation of abnormalities in the uterine cavity remains to be challenging. The volumetric ADC histogram analysis provides a mechanism for quantifying the overall heterogeneity and comprehensive assessment of a given abnormality. We demonstrated that whole-lesion ADC histogram-based texture analysis could serve as a quantitative technique of differentiating benign endometrial lesions (BELs) from stage IA endometrial cancer (EC) preoperatively. The combined ADC histogram model showed high classification ability for both premenopausal and postmenopausal patients.
Navigator-based slice tracking for kidney pCASL using EPI acquisition
Authors: Zhang Ke , Triphan Simon , Kurz Felix , Ziener Chrstian , Kauczor Hans-Ulrich , Schlemmer Heinz-Peter , Sedlaczek Oliver
Published: August 2023

Renal perfusion is an important physiological parameter in health and disease (1). To measure kidney perfusion using arterial spin labelling (ASL) the respiratory motion is a major problem. In this study, respiratory motion information is acquired from a projection signal and used to adjust the position of the excited slice in real time. The feasibility of free-breathing multi-slice kidney perfusion imaging using EPI based pseudocontinuous ASL (pCASL) with navigator-based slice tracking method is investigated.
Change in T2* measurements of placenta during Braxton Hicks contractions
Authors: Turk Esra Abaci , Stout Jeffrey , Gagoski Borjan , Manhard Mary Katherine , Adalsteinsson Elfar , Golland Polina , Roberts Drucilla , Barth William , Grant P. Ellen
Published: August 2023

Maternal-placental perfusion can be temporarily compromised by Braxton Hicks uterine contractions. The effect of Braxton Hicks contractions on placental function has not been well characterized or understood. In this study, we investigated the effect of Braxton Hicks contractions on placental T2* values across gestation together with the outcome measures. We observed positive correlation between the change in T2* during contraction, gestational age at delivery, and fetal birth weight. Additionally we observed differences in the placental T2* response in the regions closer to the maternal surface compared to regions closer to the fetal surface.
Deep Learning Model for Automatic Fetal Brain Landmark Localization in MRI
Authors: Deng Jie , Liu Xuchu , Adepoju Jubril , Byrd Sharon
Published: August 2023

Fetal MRI provides great anatomic details for diagnosis of perinatal disorders when ultrasound is inconclusive in assessing fetal anatomy during all phases of gestation. Immediate interventions can be attempted when abnormal anatomic changes of fetal brain structures are identified early during gestation. Size measurements of a fetal brain structure can be realized by identifying several landmarks of the structure accurately and calculating the distance between the landmarks. We developed a deep learning model that exploits U-net as a ‘transforming’ function to learn imaging features adjacent to a landmark point and predict the landmark location automatically.
Preliminary Evaluation of Risperidone in Huntington’s Disease: An Intravoxel Incoherent Motion (IVIM) Study
Authors: Finkelstein Alan , Uddin Md Nasir , Zhong Jianhui , Schneider Ruth , Schifitto Giovanni
Published: August 2023

Huntington’s disease (HD) is a neurodegenerative movement disorder that negatively impacts quality of life. Atypical antipsychotics are used for treatment, though with limited evidence from controlled trials. In this preliminary study we investigated the effects of risperidone, an atypical antipsychotic for the treatment of chorea in HD using intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) and volumetric analysis. Preliminary findings suggest that early effects of risperidone may present as changes in the microcirculation within the basal ganglia prior to any anatomical changes. However, further evaluation in a larger sample size is needed to better assess the clinical response to risperidone.
Low-Rank Inversion Reconstruction for Through-Plane Accelerated Radial MR Fingerprinting at 0.35T
Authors: Mickevicius Nikolai , Glide-Hurst Carri
Published: August 2023

To reduce scan time, methods to accelerate hybrid phase encoded/non-Cartesian MR fingerprinting (MRF) acquisitions for variable density spiral acquisitions have recently been developed. These methods are not applicable to MRF acquisitions wherein a single k-space spoke is acquired per frame. Therefore, we describe, implement, and test a low-rank inversion method on a 0.35T MR-guided radiation therapy system to resolve MR fingerprinting contrast dynamics from through-plane accelerated Cartesian/radial measurements.
Voxel-wise Temporal Attention Network and Simulation-Driven Dynamic MRI Sequence Reconstruction
Authors: Guo Shouchang , Fessler Jeffrey , Noll Douglas
Published: August 2023

Inspired by two open questions of dynamic MRI reconstruction, we propose a novel voxel-wise attention network for temporal modeling for the undersampled reconstruction. The voxel-wise design of the network enables voxel-wise training, and we further propose a two-stage training scheme that pretrains the network with voxel-wise simulated data when dynamics are easy to obtain with physical models. With a factor of 12 undersampling, our proposed model outperforms other reconstructions with higher PSNR and better fMRI performance.
Enhanced detection of paramagnetic fluorine-19 MRI agents using compressed sensing zero echo time sequence
Authors: Chen Jiawen , Pal Piya , Ahrens Eric
Published: August 2023

To accelerate the imaging speed and improve the signal-to-noise ratio of three-dimensional, whole body 19F MRI, we describe an ultrafast compressed sensing data acquisition scheme adapted for a zero echo time (ZTE) pulse sequence, with data reconstruction via a sparsity-promoting algorithm using a nonuniform fast Fourier transform (NUFFT) sensing operator. These methods are well suited for MRI of labeled cells using 19F tracer agents, particularly paramagnetic metallo-perfluorocarbon nanoemulsions. In phantom data and an in vivo immunotherapy mouse model, we show the feasibility of boosting MRI detection sensitivity by greater than an order of magnitude without increasing total scan time.
Inversion Recovery for Resolving the Olefinic Resonance in Spinal Bone Marrow at 3 T
Authors: Fallone Clara , Yahya Atiyah
Published: August 2023

Magnetic resonance spectroscopy measures of the olefinic resonance (≈ 5.3 ppm) enables estimation of fat unsaturation levels. In spinal bone marrow, the olefinic peak is significantly overlapped by that of water (≈ 4.7 ppm). Previously, STEAM with a TE of 100 ms was demonstrated to resolve the olefinic resonance from that of water in spinal bone marrow at 3 T. In this work, we show that an inversion recovery with short-TE STEAM (20 ms) suppresses the water signal, resolving the olefinic resonance and yielding a signal to noise ratio 3.3x larger than that obtained with long-TE STEAM.
Subject-specific Analysis for Diffusion and Kurtosis Changes in mild Traumatic Brain Injury (mTBI) Patients
Authors: Bhushan Chitresh , Abad Nastaren , Madhavan Radhika , Marinelli Luca , Morris H. Doug , Hood Maureen , DeMarco J Kevin , Shih Robert , Zhu Ante , Kohls Gail , Fiveland Eric , Kenney Kimbra , Ho Vincent , Foo Thomas
Published: August 2023

Advanced neuroimaging capabilities enabled by the MAGNUS (ultra-high performance head gradient) system was leveraged in this study to assess subject-specific microstructural changes with acute and chronic mild traumatic brain injury. MAGNUS allows for a four-fold increase in maximum gradient-amplitude compared to current clinical whole-body scanners and enables identification of new imaging biomarkers for improved detection of microstructural changes in the brain. We present an outlier analysis approach that allows study of microstructure differences in individual subjects rather than solely on a group basis. Preliminary results demonstrate identification of several white-matter regions in patient groups that differ from healthy controls.
Iterative decomposition of multi-compartment relaxometry with least square estimations (IDMCR) for UTE relaxometry in brain
Authors: Yao Jingwen , Deveshwar Nikhil , Larson Peder
Published: August 2023

To improve the fitting performance of a UTE relaxometry model, we proposed an iterative decomposition method of multi-compartment relaxometry with least square estimations (IDMCR), based on Gauss-Newton estimations and incorporating spatial constraints. Monte Carlo simulation showed that IDMCR provided robust and unbiased estimation of ultra-short T2* myelin fraction, which was further improved by adding spatial constraints. We examined the fitting algorithm in one healthy volunteer UTE relaxometry data and showed clear contrast of gray and white matter on the fitted myelin fraction map. The framework of IDMCR could also be easily adapted for other nonlinear parameter fitting problems.
An iron-based hypoxia targeting contrast agent
Authors: Moghadas Babak , Quarles C. Chad , Kodibagkar Vikram
Published: August 2023

We developed and tested a novel iron based contrast agent for imaging hypoxia using magnetic resonance imaging (MRI). After synthesis, the cytotoxicity data and the magnetic properties were studied to measure the relaxivity of the contrast agent. The ability of the contrast agent in targeting hypoxic was demonstrated in vitro by comparing cell cultures under hypoxia by T1 and T2 mapping. The cytotoxicity assay showed no significant changes to the cells’ viability over the period of 8h exposure to the contrast agent. The retention in the hypoxic condition is an indication of its performance under the proposed mechanism.
B1 field flattening and length control of half-wave dipole antenna with discrete dielectric coating
Authors: Bhosale Aditya , Gawande Divya , Zhang Xiaoliang
Published: August 2023

This study presents a method for the B1 field flattening and length control of the half-wave dipole antenna for MR imaging with discrete dielectric material coating. To demonstrate this method, we designed a half-wave dipole antenna to operate at 300MHz, including coating the ends of the dipole conductors with a high dielectric material, serving as a way to control the dipole length and electromagnetic field distribution. We also compare the proposed technique with the conventional half-wave dipole antenna and show how the new technique effectively tunes the shorter half-wave dipole antennas at specific frequencies and produces efficient field distributions.
A 16-channel splittable non-overlapped self-decoupled loop transmitter for 10.5 Tesla human head imaging
Authors: Waks Matt , Tavaf Nader , Lagore Russell , Jungst Steve , Radder Jerahmie , Grant Andrea , DelaBarre Lance , Van de Moortele Pierre-Francois , Adriany Gregor , Ugurbil Kamil
Published: August 2023

A 16-channel dual row loop transmitter utilizing self-decoupling principles has been designed and prototyped for human head imaging at 10.5 Tesla. The coil employs an intentional asymmetry of impedances within each coil element in order to reduce the interaction between coil elements. Electromagnetic simulations provide an estimate for achievable decoupling and the expected loop current distribution with both a phantom load and a human head model. Bench measurements confirmed the simulation results and indicated coil to coil decoupling on the order of -10 dB or better. MR experimental results indicated minimal interaction with our 63 channel receiver array.
A 24-channel Array for Awake NHP Imaging at 10.5 Tesla
Authors: Jungst Steve , Lagore Russell , Waks Matt , Zimmermann Jan , Adriany Gregor
Published: August 2023

A 24-channel receiver – dual channel transmitter array for awake monkey imaging at 10.5 Tesla is presented. This was achieved by adding an 8-channel extension to a previously built 16-channel receive array. The new layout does not require any user adjustments and fully supports monkey imaging.
0.2 mm Isotropic Intracranial Perforating Arteries Imaging using Compressed Sensing TOF-MRA at 7T
Authors: Zhang Zhe , Kong Qingle , Jing Jing , Wang Yongjun
Published: August 2023

The impairment of microvessels can lead to neurologic diseases such as stroke and vascular dementia. The imaging of perforating arteries requires an extremely high resolution due to their small caliber size. In this study, we optimized the parameters of compressed sensing (CS) TOF-MRA to achieve isotropic 0.2 mm lenticulostriate artery (LSA) images within 10 minutes at 7T. More LSA stems and branches were delineated in CS TOF images compared with conventional TOF images. CS TOF-MRA can be a state-of-the-art method for detecting microvasculopathies of cerebral vascular diseases.
Microstructural alterations in projection and association fibers in neonatal hypoxia-ischemia
Authors: Cao Zuozhen , Shen Xiaoxia , Gao Fusheng , Liu Tingting , Zhao Zhiyong , Zhang Hongxi , Du Lizhong , Zhang Jiangyang , Zhang Yi , Lai Can , Ma Xiaolu , Wu Dan
Published: August 2023

Diffusion MRI (dMRI) is known to be sensitive to hypoxic-ischemic encephalopathy (HIE) , however, the existing dMRI studies only used diffusion tensor metrics in a few selected brain regions and primarily focus on severe-to-moderate HIE. Here we investigated microstructural alterations using multi-shell dMRI across the whole-brain in severe, moderate, and mild HIE babies (n=5/13/13) in comparison with control neonates (n=11) with region-of-interest-based, tract-based, and fixel-based analysis. We found microstructural alternations in projection and association fibers, especially the inferior fronto-occipital fasciculus and inferior longitudinal fasciculus that are important for visual functions.
Comparative study between the Slow Infusion MR angiography and CT angiography in detection of the Adamkiewicz artery
Authors: Mizushima Shohei , Mine Takahiko , Abe Masashi , Hayashi Hiromitsu , Fujii Masahiro , Sekine Tetsuro , Yokoyama Taro , Ikeda Shinpei , Happoh Seigoh , Kumita Shin-ichiro
Published: August 2023

The Slow-Infusion MRA with SPGR provided the higher detectability of the AKA with whole patients, all AD patients, and with the AD patients whose AKA originating from false lumen in comparison with CTA.
Liver DWI using deep learning constrained compressed sensing: A primary study compared to conventional DWI and compressed sensing-based DWI
Authors: Duan Ting , Zhang Zhen , Jiang Hanyu , Chen Yidi , Zhang Xiaoyong , Song Bin
Published: August 2023

Compressed sensing AI-based DWI substantially reduced noise artifacts and improved the signal-to-noise ratio and lesion contrast-to-noise ratio compared with conventional DWI and Compressed sensing based DWI, without any penalty for scan parameters. This technique may prove of value in better diagnostic liver imaging.
Dynamic MRI Reconstruction of the Whole Liver with High Acceleration using Low Rank Tensor and Weighted Group Sparsity
Authors: Liu Bei , She Huajun , Zhang Yufei , Ding Zekang , Wang Zhijun , Du Yiping
Published: August 2023

We propose an algorithm for dMRI reconstruction from highly under-sampled k-space data acquired during free breathing. Stack-of-star GRE radial sequence with self-navigator is used to acquire the data. We explore spatial and temporal redundancy for the reconstruction by using weighted group sparsity, weighted sparsity, and low-rank tensor. Additionally, a tensor total variation is used to ensure spatial and temporal smoothness. By applying a weighting function to the sparsity and group sparsity, the subtle structural sparsity features in the sparse domain can be better utilized. The proposed algorithm has the potential to be used in clinical applications such as MR-guided surgery.
Assessment of fibrotic liver regeneration with IVIM imaging: an experimental study in a rat model
Authors: Xie Shuangshuang , Qiu Caixin , Sun Yajie , Zhu Jinxia , Grimm Robert , Shen Wen
Published: August 2023

This study investigated the feasibility of IVIM to evaluate fibrotic liver regeneration and function recovery after partial hepatectomy in a rat model. In fibrotic rats, significant increase in D values and decrease in D* and PF values followed with recovery to pre-PH levels were shown. PF values correlated well with Ki-67 indices, D* and PF values correlated well with ALT, AST, and TBil values. IVIM may be an noninvasive and promising approach to monitor liver regeneration and functional recovery after PH.
Evaluation of interstitial lung diseases using free-breathing 3D isotropic ZTE-MRI in comparison with High-resolution computed tomography
Authors: Lin Qiuxi , Deng Yu , Li Xinchun , Liu Weiyin , Zhang Lei , Zhang Ziyi , Luo Qun , Wan Qi , Sun Chongpeng
Published: August 2023

Pulmonary MRI provides qualitative structural and quantitative functional images of the lungs without ionizing radiation. In this study, free-breathing 3D isotropic high-resolution pulmonary zero echo time (ZTE) imaging was applied to detect pulmonary abnormalities and make diagnosis of interstitial lung diseases (ILDs). The pulmonary interstitial abnormalities including ground-glass opacity, reticular opacity, honeycombing, traction bronchiectasis and consolidation can be well depicted. The diagnosis performance of ZTE in ILDs is comparable with HRCT. ZTE might assist long-term follow-ups in ILDs evaluation without radiation exposure.
Amide proton transfer weighted and intravoxel incoherent motion imaging in evaluation of prognostic factors for rectal adenocarcinoma
Authors: Li Juan , jingliang cheng , Liangjie Lin
Published: August 2023

This study explored the application of APT and IVIM in evaluation of prognostic factors for rectal adenocarcinoma. Parameters of APT signal intensity (APT SI), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), and apparent diffusion coefficient (ADC) were measured. The results showed that APT SI was significantly lower in low- than high-grade adenocarcinoma. The D value was significantly higher in low- than high-grade adenocarcinoma. The D value was significant lower in positive than in negative extramural vascular invasion (EMVI). This suggests that APT and IVIM were helpful to assess rectal adenocarcinoma, including histopathological grade and the EMVI status.
DKI and IVIM for Assessment of Rectal Cancer: Correlations between Imaging Parameters and Tumor Tissue Composition
Authors: Yuan Jie , Liu Mengxiao , Zhan Songhua , Gong Zhigang , Shen Qiang
Published: August 2023

It is important to combine histopathological and non-invasive imaging measurements to assess tumor components and predict tumor invasiveness to define disease treatment and prognostic assessment. In this study, we assessed the relationships between DKI and IVIM parameter measurements and the corresponding tumor tissue composition, regardless of the status of the malignant tumor. To this end, we selected a range of tissue parameters informative for important biological properties of the tumor, such as Ki-67, the tumor: stroma ratio, CD34 etc.
T2-weighted dynamic approach for rectal MR imaging
Authors: Cheng Jing , Li Jiansen , Yang Jun , Zhang Huimao , Li Guobin , Liu Xin , Liang Dong
Published: August 2023

T2-weighted MR imaging is the standardized protocol in clinical evaluation of rectal cancer and anatomic structures. Usually, spasmolytic agent injection is required before the examination to reduce the imaging artifacts caused by the rectum peristalsis. In this work, we propose a novel dynamic imaging approach that with a complementary k-space sampling strategy and deep learning-based image reconstruction method to illustrate the anatomical structures of the rectum without any agent injection. Experimental results demonstrate the superior performance of the proposed approach.
Comparative Study of histogram analysis of Intravoxel Incoherent Motion and Diffusion Kurtosis Imaging for the staging of liver fibrosis
Authors: Fan Fengxian , Jiang Yanli , Zhang Jing , Zou Jie , Ren Jialiang
Published: August 2023

The purpose of this study is to compare the diagnostic accuracy of histogram analysis–derived parameters from intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) for staging of liver fibrosis (LF). The correlations between different histopathologic stages and histogram parameters were determined. The results showed that the histogram metrics of DKI maps demonstrate significant correlation with fibrosis stage, while there was no correlation between histogram metrics of IVIM and fibrosis stage. In conclusion, histogram analysis of DKI may serve as a valuable and robust tool for the staging of LF.
Gadoxetic Acid–enhanced MRI for Predicting Postsurgical Recurrence in Hepatocellular Carcinoma：Compared with Four Clinical Staging Systems
Authors: Wei Hong , Jiang Hanyu , Song Bin
Published: August 2023

A total of 214 patients with pathologically confirmed Hepatocellular carcinoma (HCC) who underwent gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) before curative resection between July 2015 and November 2020 were retrospectively included in this study. The preoperative model integrating EOB-MRI findings and serum AFP and AST levels achieved accurate recurrence prediction in HCC, with similar performance to that of the postoperative clinical-radiologic-pathologic model. Moreover, the preoperative model yielded superior predictive performance to four widely used clinical staging systems for HCC recurrence prediction. This model offered a potential noninvasive and reliable approach for individualized recurrence risk estimation before hepatectomy.
Feasibility of Using Multi-frequency MR Elastography for the Assessment of Pancreatic Stiffness and Fluidity in Healthy Volunteers
Authors: Shi Siya , Luo Yanji , Wang Liqin
Published: August 2023

Tomoelastography, a newly emerging imaging modality, is a multi-frequency magnetic resonance elastography technique using noise-robust data post-processing. The aim of our study was to investigate the assessment of stiffness and fluidity of pancreas in healthy volunteers with tomoelastography. Tomoelastography derived pancreatic stiffness and fluidity were near-perfect reproducible in healthy volunteers. There was no stiff or fluidic difference among different groups of sex, age, BMI or pancreatic anatomical region. Tomoelastography can provide stable and promising stiffness and fluidity measurements throughout the pancreas. Our results provide data that will enable pancreatic studies of tomoelastography as a potential clinical tool in future.