bluuebunny/crossref_metadata_2025 huggingface dataset:
Region-specific effects of neonatal hyperbilirubinemia on the developing brain in a preterm Gunn rat model
Authors: Tkac Ivan , Satrom Katherine , Rao Raghavendra
Published: August 2023

Preterm Gunn rat model of neonatal hyperbilirubinemia (NHB) was used to investigate effects of unconjugated bilirubin (UCB) on the developing hippocampus and cerebellum. In this model, sulfadimethoxine was injected (i.p.) to Gunn rat pups on postnatal day 5 to exaggerate NHB effects at a preterm equivalent age. 1H MRS and MRI results clearly demonstrate that high levels of UCB in early postnatal age critically affects the brain development in a region-specific manner. In this model, cerebellum appears to be much more vulnerable to high levels of UCB than hippocampus resulting in abnormal postnatal development.
Radiomic biomarker extracted from PI-RADS 3 patients support more efficient and robust prostate cancer diagnosis: a multi-center study
Authors: Li Longfei , Yang Rui , Chen Xin , Li Cheng , Zheng Hairong , Lin Yusong , Liu Zaiyi , Wang Shanshan
Published: August 2023

Prostate Imaging Reporting and Data System (PI-RADS) based on multi-parametric MRI classifies patients into 5 categories (PI-RADS 1-5) for routine clinical diagnosis guidance. However, there is no consensus on whether PI-RADS 3 patients should go through biopsies. Mining features from these hard samples (HS) is meaningful for physicians to achieve accurate diagnoses. Currently, the mining of HS biomarkers is insufficient, and the effectiveness and robustness of HS biomarkers for prostate cancer diagnosis have not been explored. In this study, biomarkers from different data distributions are constructed. Results show that HS biomarkers can achieve better performances in different data distributions.
Workflow development for kidney segmentation using a U-net model using 11000 MRI data sets from the German National Cohort (NAKO/GNC) study
Authors: Buechert Martin , Lipovsek Jan , Reisert Marco , Horbach Harald , Reichardt Wilfried , Schlett Christopher , Bamberg Fabian , Sekula Peggy , Köttgen Anna , Kellner Elias
Published: August 2023

A processing pipeline for kidney segmentation using a hierarchical patch-based stack of U-nets was implemented and applied to abdominal MRI images of the German National Cohort study. The training data set included 300 cases and the final net was applied to the dataset of 11,207 MRIs. The compartments cortex, medulla and hilus could be segmented very robustly with the network. The relation of first parameters based on the segmentation withsex, age, weight, subject size and BMI are presented. This is an optimal starting point to identify more advanced biomarkers and their correlations, especially with kidney functional parameters.
Optimization of GLCM Texture Analysis settings in Liver Radial T2 Maps: Fibrotic vs Healthy Liver
Authors: Bencikova Diana , Janacova Veronika , Raudner Marcus , Ba-Ssalamah Ahmed , Trattnig Siegfried , Krssak Martin
Published: August 2023

GLCM texture analysis is a promising technique for characterizing and classifying tissue pathologies. In liver applications it has been mostly performed on T2-weighted images. Fast radial T2 mapping techniques enable acquiring T2 maps in clinically feasible measurement time (during breath-hold). Here, we explored the performance of the different settings of GLCM texture analysis in liver T2 maps, which might be more advantageous compared to T2-weighted images. We identified the grey-level quantization of 8bits and direction of 90° as the best setting for discrimination between fibrotic and healthy livers.
Developing a Delta Radiomics Framework for Prostate Cancer Progression Biomarkers in Patients under Active Surveillance: Pilot Study
Authors: Dewi Dyah Ekashanti Octorina , Sunoqrot Mohammed R. S. , Nketiah Gabriel Addio , Sandsmark Elise , Langørgen Sverre , Bertilsson Helena , Elschot Mattijs , Bathen Tone
Published: August 2023

Identification of progressive lesions over time is important to monitor the prostate cancer progression in active surveillance. Delta Radiomics, computed as the relative changes of features among scans, provides temporal evolution of features that may indicate clinical changes along time periods. This pilot study aims to develop a framework to identify progressive lesions on two long-term scans in prostate T2WI based on Delta-radiomics. The current results show that four Delta-radiomics features from GLDM and Shape feature groups have potentials to identify progressive lesions compared to other selected reproducible features.
Comparison of magnetization transfer quantification methods in the sciatic nerve of Charcot-Marie-Tooth Type 1A patients
Authors: Roth Alison , Chen Yongsheng , Li Jun , Dortch Richard
Published: August 2023

Magnetization transfer (MT) can be quantified as the MT ratio (MTR), MT saturation (MTsat), and quantitative MT (qMT) pool-size-ratio (PSR). MTR is a promising peripheral nerve imaging biomarker in inherited neuropathies but has lower pathological specificity compared to MTsat and PSR. Here, MTR and MTsat metrics are compared to PSR. Eighteen subjects received 16 qMT scans, five T1-weighted scans, and the B0 and B1 fields were measured. Mean MTR, MTsat, and PSR were extracted from the sciatic nerve. MTR had the highest SNR (median>15.76) and scan-rescan repeatability (ICC=0.93, CV=4.6%), whereas MTsat had the strongest correlation to PSR (r=0.94, p<0.001).
Post mortem study of R2* and vessel distance maps across cortical depth
Authors: Mattern Hendrik , Angenstein Frank , Mawrin Christian , Perosa Valentina
Published: August 2023

In this proof-of-principle study, an image acquisition and processing pipeline was developed to assess the cortical vasculature and its surrounding tissue. To that end, a block of human brain, which included cortex and juxtacortical white matter, was scanned post-mortem at high resolution with a multi-echo GRE sequence at 9.4T. Subsequently, R2* and vessel distance maps (VDM) were computed and their layer-specific patterns analyzed.
A hybrid EPG-hGLLiM method for accurate fat-signal modeling in skeletal muscle T2 mapping
Authors: Baudin Pierre-Yves , de Almeida Araujo Ericky Caldas , Reyngoudt Harmen , Marty Benjamin
Published: August 2023

In order to improve the reliability of the muscle T2 as a clinical outcome in clinical studies of neuromuscular disorders, we investigate the accuracy of the fat signal modeling in transverse relaxometry from multi-spin echo imaging. A new approach for muscle T2/fat-fraction mapping is proposed, combining a water signal dictionary with water T2/B1-dependent entries created from EPG simulations, and a hybrid Gaussian Locally Linear Mapping (hGLLiM) to provide B1-dependent fat signals. Preliminary results on a dataset of healthy controls, DMD and IBM patients are consistent with common knowledge, but interesting divergences are found when compared to another recent approach.
STEAM-based proton observed carbon edited (POCE) 13C magnetic resonance spectroscopy without decoupling at 7T
Authors: Xiao Ying , Wenz Daniel , Xin Lijing
Published: August 2023

1H-[13C] NMR spectroscopy is a powerful tool to study metabolic information in human brain. At 7T, the proton-observed carbon-edited (POCE) method provides high sensitivity and improved spectral resolution. However, the application in human brain has more constraints due to high RF power deposition at 7T. In this study, we investigated the performance of the STEAM-based POCE sequence without decoupling to reduce the RF power. The phantom experiments and the Monte Carlo simulations demonstrated high-quality 1H-[13C] MR spectra and the accurate quantification of 13C-labeled glutamate and glutamine without decoupling at 7T.
Short-TE diffusion-MRI by combining strong gradients with ultrasonic readout
Authors: Ieperen Aris , Tax Chantal , Klomp Dennis , Vermulst Bas , Siero Jeroen , van Straalen Joost , Heintges Martijn , Versteeg Edwin
Published: August 2023

For high-resolution diffusion-MRI, strong gradients combined with fast readout are desired. In this study, we propose a gradient system architecture for such strong gradients and fast readouts without nerve stimulation by implementing a filter topology that allows for both low and high frequency gradient waveforms. Two gradient inserts with different specifications are realized and two proposed modulation strategies are implemented in the amplifier firmware. Field measurements demonstrated the desired dual-mode capability of the system. With one gradient insert, a gradient amplitude of 300 mT/m and slew rates well above 10.000 T/m/s can be reached with only 500A&330V as amplifier output.
Z-Gradient Array Coil Equipped with a Tunable Shield Array for Creating Multiple-Imaging Volumes
Authors: Takrimi Manouchehr , Atalar Ergin
Published: August 2023

A z-gradient array coil equipped with a tunable shield array is proposed to achieve multiple imaging volumes that can be shifted along the coil axis. This is achieved by a set of independently tunable power amplifiers that feed the array elements. The proposed array dynamically provides a proper shield for the main array in which its magnetic profile can be adjusted on the fly. Five multiple-region magnetic profiles are simulated to demonstrate the flexibility of the proposed array: (a) a double-gradient profile; (b) shifted version of (a); (c) highly linear double-gradient profile without shielding; (d) triple-gradient profile; (e) quintuple-gradient profile.
Diffusion Imaging comparison of high-performance Gradient system (MAGNUS) with clinical MR system.
Authors: Morris H. , Abad Nastaren , Madhavan Radhika , Bhushan Chitresh , Zhu Ante , Marinelli Luca , Fiveland Eric , DeMarco J Kevin , Shih Robert , Hood Maureen , Kohls Gail , Kenny Kimbra , Foo Tom , Ho Vincent
Published: August 2023

Comparisons of the multi-shell DWI is described for the USU/GE MAGNUS 3T head-only gradient system and a clinical whole-body GE MR750 3T magnet system. The advantages of high-performance gradients are shown in analysis outcomes of dMRI metrics. Direct comparison is made between identical diffusion pulse sequences and system optimized sequences for each platform. The shorter TE and high-gradient strength of MAGNUS enhance SNR and diffusion imaging response.
Reducing MRI acoustic noise burden with Predictive Noise Cancelling
Authors: Šiurytė Paulina , Tourais Joao , Weingärtner Sebastian
Published: August 2023

Acoustic noise in MRI is a main source of patient anxiety, with noise levels reaching up to 130 dB. In this work, a low-cost solution is proposed, combining active noise cancelling and direct sequence noise prediction from the scanner gradient inputs. The prediction is based on the linearity between gradient coil input derivative and corresponding acoustic noise. A proposed Predictive Noise Cancelling demonstrated an in-bore noise reduction up to 10 dB despite the system imperfections.
Hybrid Superconducting-Permanent Magnet Designs for Short Mid-Field MRI Magnets
Authors: Barksdale Alex , Cooley Clarissa , Wald Lawrence
Published: August 2023

Mid-field (0.5T) MRI is an attractive alternative to higher field strengths for improved cost, accessibility and patient comfort. Magnet length is a major determinant of patient comfort/acceptance but is constrained by escalating wire costs. We present a mid-field magnet design using rare-earth permanent magnets to supplement solenoidal superconducting windings, enabling shorter bore lengths than superconducting windings alone. The optimization problem is formulated and solved using linear programming. For a given superconducting wire length, we demonstrate that adding rare-earth materials can reduce bore lengths by 10% using <250kg of rare-earth material for a 5ppm, 0.5T B0 specification over a 450mm DSV.
A Fast Magnetostaic Inverse Approach for Subject-Specific ∆B0 Shim Coil Calibration
Authors: Arango Nicolas , White Jacob , Adalsteinsson Elfar
Published: August 2023

For a rigidly positioned ∆B0 shim coil, calibration is a one-time process of acquiring high resolution ∆B0 fields. For subject-specific shim coil position, this approach is too slow. We propose a fast magnetostatic inverse approach for subject-specific calibration by only acquiring few, low resolution fieldmaps each with several active shim coils. Our simulation study, which included a noise model and a measured ∆B 0 test case, suggests a scan-time reduction of afactor of 170, reducing calibration time from over an hour to less than a minute with negligible impact on shim quality.
Efficient Dixon-Based 3D Fast Spin-Echo MR Neurography of Lumbosacral Plexus
Authors: Han Misung , Chin Cynthia , Majumdar Sharmila
Published: August 2023

MR neurography (MRN) provides direct visualization of peripheral nerves and allows for detecting pathologies. Isotropic 3D MRN has been suggested as an effective method to evaluate overall nerve structures and subtle morphological changes; however, its clinical applications to the lumbosacral plexus have been limited. In this work, we optimized 3D FSE acquisition combined with a Dixon fat-water separation technique to provide uniform signal over the large volume and to suppress vessel signal. In vivo experiments with patients having a lower back pain at 3T demonstrated the clinical feasibility of using the proposed methods for evaluating nerve pathologies.
Quantitative Evaluation of Normal Lumbosacral Plexus Nerve Using Diffusion Tensor Imaging with Multiband SENSE
Authors: Zhang Nan , Chen Caizhong , Song Qingwei
Published: August 2023

DTI can provide valuable structural information that may become an innovative tool in evaluating lumbosacral plexus nerve entrapment. Multiband SENSE technique could be used to accelerate the image acquisition .The present study aims to explore the feasibility of DTI with multiband SENSE on normal lumbosacral plexus nerve. The study showed that MB SENSE=2 was recommended for DTI on normal lumbosacral plexus nerve, which facilitated a 32% shorter image acquisition time than conventional SENSE accelerated diffusion tensor imaging.
Assessment of Fat Fractions of Tongues, Pharyngeal Walls, and Soft Palates by GOOSE and DIXON methods
Authors: Song Ruitian , Hwang Scott , Goode Chris , Storment Diana , Scoggins Matthew , Abramson Zachary , Hillenbrand Claudia , Mandrell Belinda , Krull Kevin , Reddick Wilburn
Published: August 2023

Among 63 participants, the fat fractions (FFs) were estimated and compared in tongues, posterior pharyngeal walls (PPWs), and soft palates (SPs) using two-point DIXON and GOOSE (Globally Optimal Surface Estimation) methods. DIXON was seriously impaired by B0 inhomogeneity and underestimated FF relative GOOSE. There was a strong correlation between these two methods in the tongues and SPs, and a weak one in the PPWs. In our opinion, an IDEAL-based method is preferred for estimating fat content. Extra attention is needed when using the two-point DIXON method.
Image quality of high-resolution three-dimensional neck MRI using CAIPIRINHA-VIBE and GRASP-VIBE: an intra-individual comparative study
Authors: Seo Minkook , Yoon Jimin , Choi Yangsean , Jang Jinhee , Shin Na-Young , Ahn Kook-Jin , Kim Bum-soo
Published: August 2023

The image qualities of two high-resolution MRI sequences of the neck—CAIPIRINHA-VIBE and GRASP-VIBE—were compared. 173 patients clinically indicated for neck MRI were scanned using both sequences with isotropic (<1 mm) in-plane resolution. The image quality was qualitatively assessed by two radiologists. Quantitative assessments (i.e., non-uniformity, contrast-to-noise ratio and signal-to-noise ratio) were performed in all patients, a phantom and a healthy volunteer. GRASP-VIBE outperformed CAIPIRINHA-VIBE in all qualitative assessments except for the fat suppression degree. Quantitative assessments were significantly superior in GRASP-VIBE than in CAIPIRINHA-VIBE. Therefore, GRASP-VIBE may be a better alternative to CAIPIRINHA-VIBE for head and neck MRI.
Improved 3D stack-of-spiral UTE pulmonary imaging at 0.55T using iterative concomitant field and motion corrected reconstruction (iCoMoCo)
Authors: Javed Ahsan , Ramasawmy Rajiv , Moss Joel , Majeed Waqas , Su Pan , Benkert Thomas , Bhat Himanshu , Malayeri Ashkan , Campbell-Washburn Adrienne
Published: August 2023

Lung MRI using a high-performance 0.55T system offers reduced susceptibility artifacts, but high resolution imaging is challenged by low proton density, reduced signal-to-noise ratio, and concomitant-fields. 3D spiral acquisitions can be used for improved efficiency and SNR, at the expense of concomitant field related blurring. We present a self-gated, ultra-short echo time, stack-of-spirals acquisition with an efficient inline iterative reconstruction (<15 min) that incorporates both concomitant-field and motion-correction to enable robust high-resolution lung imaging at 0.55T. Our optimized and efficient imaging method is applied to improve image quality in healthy volunteers, patients with lung nodules, and patients with lymphangioleiomyomatosis (LAM).
3D Pulmonary Perfusion Mapping Using 3D Ultrashort Echo-time Imaging
Authors: Kim Hyeonha , Lee Seokwon , Park Jinil , Park Jang-Yeon
Published: August 2023

Lung MRI is getting more interest as an alternative to CT because of no radiation exposure and expands its role of providing structural information to functional information such as ventilation and perfusion. In terms of 3D functional imaging, 3D ventilation mapping was already proposed, but few studies have been done on 3D perfusion mapping. Here, we propose a 3D pulmonary perfusion map using 3D UTE-MRI with retrospective respiratory and cardiac gating. The proposed method provides high-resolution 3D regional perfusion information of the lungs and will be useful for diagnosing diffusive lung diseases along with ventilation map (e.g., V/Q ratio).
Variation of Proton Lung Signal with Ventilation at 3T
Authors: Peggs Zachary , Brooke Jonathan , Cooper Andrew , Bolton Charlotte , Hall Ian , Francis Susan , Gowland Penny
Published: August 2023

The nature of MR signal variations during healthy ventilation at 3T were explored in 8 healthy participants. Fourier decomposition (FD) techniques were used to remove cardiac signal contributions, and the phase, correlation coefficient and gradient of the parenchyma signal with respect to diaphragm signal were found. This analysis showed that for some voxels, the relationship between parenchyma signal and diaphragm signal is distinctly non-linear. Also, that breathing pattern is an important confounding factor when using the diaphragmatic movement as a surrogate for the change in lung volume, where an additional measure such as a separate 3D acquisition may prove beneficial.
The impact of learning rate, network size, and training time on unsupervised deep learning for intravoxel incoherent motion (IVIM) model fitting
Authors: Kaandorp Misha , Zijlstra Frank , de Almeida Martins João , Federau Christian , While Peter
Published: August 2023

We demonstrate that a high learning rate, small network size, and early stopping in unsupervised deep learning for IVIM model fitting can result in sub-optimal solutions and correlated parameters. In simulations, we show that prolonging training beyond early stopping resolves these correlations and reduces parameter error, providing an alternative to exhaustive hyperparameter optimization. However, extensive training results in increased noise sensitivity, tending towards the behavior of least squares fitting. In in-vivo data from glioma patients, fitting residuals were almost identical between approaches, whereas pseudo-diffusion maps varied considerably, demonstrating the difficulty of fitting D* in these regions.
Evaluation of SS3T-CSD for the analysis of diffusion MRI data - a simulation study
Authors: Tang Jibin , Pietsch Maximilian , Tournier Jacques-Donald
Published: August 2023

Single-shell three-tissue constrained spherical deconvolution (SS3T-CSD) has been proposed to decompose the dMRI signal into three different tissue types from single-shell data. Here, we evaluate the SS3T-CSD method over a range of different situations using real data and simulations, varying parameters including SNR, partial volume effect, b-value, number of iterations, and tissue response functions. We evaluate their effect on results by comparing with the ground truth and the results estimated from MSMT-CSD. Our results indicate that while SS3T-CSD performs well, it is sensitive to some of these factors and shows some deficiencies in certain situations.
Time dependence at ultra-high diffusion weighting reveals fast compartmental exchange in rat cortex in vivo
Authors: Olesen Jonas , Ianus Andrada , Shemesh Noam , Jespersen Sune
Published: August 2023

The potential effect of compartmental water exchange and somas on the diffusion MRI signal in grey matter tissue are currently open questions with considerable implications for biophysical modelling of grey matter at (pre-)clinical diffusion time scales. Recent studies have begun to tackle these questions and found evidence that compartmental water exchange dominates the diffusion time dependence. Here, we extend the application of the Standard Model with exchange between the neurites and extracellular water (SMEX) to in vivo rat brain and again find evidence for exchange-dominated time dependence with very short neurite residence time on the order of 2 ms.
Understanding Alzheimer's disease through fMRI and deep learning
Authors: Wacher Sarah , Lv Jinglei , Cabezas Mariano
Published: August 2023

Deep learning approaches for Alzheimer's disease (AD) classification have primarily focused on modelling the structural changes associated with the condition, neglecting the changes in functional brain dynamics. These functional changes may be detectable earlier than structural atrophy providing an avenue for earlier diagnosis and treatment. We therefore proposed a convolutional neural network combined with a long short-term memory unit to decode fMRI signals. The model was able to classify AD from healthy control with a balanced accuracy of 0.69. Whilst there is room to improve network performance, the study already provides promising insights into the possibilities of resting-state fMRI classification.
Classification of Chemotherapy-Related Subjective Cognitive Complaints in Breast Cancer Using Multi-Level Features of Functional MRI
Authors: Wang Lei , Zhou Fuqing
Published: August 2023

Chemotherapy-related cognitive impairment (CRCI), especially subjective cognitive complaints (SCC), had been often reported in breast cancer survivors, which affects their life and work. The identification of biomarkers for early diagnosis and prognosis prediction of SCC remains a crucial challenge of important clinical implications. The resting-state functional magnetic resonance imaging (rs-fMRI) has been widely used to detect abnormalities of brain activity in CRCI. The machine learning method combined with rs-fMRI features could effectively identify breast cancer survivors with chemotherapy-related SCC from healthy controls (HC).
Multi-Channel Deep Learning for IDH Mutation Status Prediction in Gliomas：A Multimodal Approach
Authors: Wang Jin , Deng Jiayang , Wang Rui , Zhang Jing
Published: August 2023

Isocitrate dehydrogenase (IDH) mutation status has emerged as an important prognostic marker in gliomas.Currently, reliable IDH mutation determination requires invasive surgical procedures. Various studies have demonstrated the efficacy of deep learning in classify IDH status using Magnetic resonance images（MRI）data.In this study we propose a multi-channel architecture of 3D convolutional neural networks (CNNs) based on deep learning to predict the IDH status.We utilize traditional structures imaging and various diffusivity metric maps derived from diffusion tensor imaging (DTI) as input to the network.The final model achieved the AUC value of 0.93.
Radiomics signature from multiparametric MRI as early in-vivo biomarkers for pseudoprogression in recurrent glioblastoma patients.
Authors: Piram Lucie , Clément Acquitter , Gilhodes Julia , Sabatini Umberto , Moyal Elizabeth Cohen-Jonathan , Lemasson Benjamin , Ken Soleakhena
Published: August 2023

Radiomic features computed from multiparametric MRI were found to be relevant as early in-vivo biomarkers for pseudoprogression evaluation in recurrent glioblastoma patients. At baseline, predictive biomarker for pseudoprogression outcome was related to kurtosis parameter of FLAIR histogram plotted from abnormal hyper-intense signal area. When considering variation between baseline and first event (either pseudoprogression or true progression), four early biomarkers were found for entropy of T1-weighted, T1-weighted-post-contrast morphological MRI and Apparent Diffusion Coefficient maps derived from diffusion-weighted MRI.

Such early in-vivo biomarkers easily computed from automatic segmentation and first order radiomics analysis could be useful for the assessment of treatment response.
Performance characterization of three coils for whole brain and/or cervical spinal cord MRI at 7T
Authors: Rangaprakash D , Guerin Bastien , Stockmann Jason , May Markus , Rios Nibardo Lopez , Gilbert Kyle , Chang Yulin , Wald Lawrence , Cohen-Adad Julien , Keil Boris , Barry Robert
Published: August 2023

Several neurological diseases affect both the brain and spinal cord. 7T MRI enables better imaging of the narrow cord as well as single-subject prediction using fMRI. However, concurrent brain-cord 7T imaging requires a coil with good SNR and acceleration capabilities in both head and neck, which has been unavailable. To overcome this, we performed flip-angle, SNR, g-factor and tSNR characterization of a custom-built 16Tx/64Rx head/neck radiofrequency coil. We also compared it against a custom-built 8Tx/20Rx cervical spine coil as well as a commercial 8Tx/32Rx brain coil. This hardware will pave the way for concurrent brain-cord 7T MRI in the future.
Myelin-sensitive MRI metrics correlate with inflammation in human traumatic spinal cord injury
Authors: Morris Sarah , Swift-LaPointe Taylor , Yung Andrew , Prevost Valentin , George Shana , Bauman Andrew , Kozlowski Piotr , Samadi Farah , Fournier Caron , Parker Lisa , Dong Kevin , Streijger Femke , Hirsch-Reinshagen Veronica , Moore G.R. Wayne , Kwon Brian , Laule Cornelia
Published: August 2023

We investigated the correlation of inhomogeneous magnetisation transfer ratio (ihMTR), myelin water fraction (MWF) and intra/extra-cellular water geometric mean T2 (I/EW gmT2) with the distribution of inflammatory cells as measured by HLA-DR and CD68 histological staining for macrophages and activated microglia in human traumatic spinal cord injury. We found that ihMTR and MWF decreases were strongly correlated with the presence of HLA/CD68+ immune cells in white matter and both ihMTR and MWF were strongly correlated with LFB, a stain for myelin lipids. Our results demonstrate a strong link between ihMTR and MWF and inflammation.
Making myelin water imaging “normal”: Robust acquisition for cervical cord with low peripheral nerve stimulation
Authors: Balaji Sharada , Dvorak Adam , Wiley Neale , Barlow Laura , Vavasour Irene , MacKay Alex , Kolind Shannon
Published: August 2023

The standard myelin water imaging (MWI) sequence for cervical spinal cord, 3D gradient and spin echo (GRASE), was modified to allow scanning in “normal mode” (limiting imaging parameters that may cause physiologic stress) for patients who may not tolerate peripheral nerve stimulation or tissue heating due to MR-conditional implants or medical issues. Traditional 32-echo GRASE was replaced with 48-echo GRASE in normal mode. Myelin water fraction maps from the new sequence had better repeatability than the standard sequence. 48-echo GRASE is the recommended sequence for MWI in spinal cord, particularly for subjects who cannot be scanned outside of normal mode.
Lumbosacral spinal cord changes after acute spinal cord injury: preliminary results of an MRI study
Authors: Büeler Silvan , Freund Patrick , Kessler Thomas , Liechti Martina , David Gergely
Published: August 2023

Imaging of the lumbosacral enlargement (LSE) has previously demonstrated remote degeneration below a cervical spinal cord injury leading to progressive atrophy of grey and white matter. Here, we investigate, for the first time, neurodegeneration in the conus medullaris (including the LSE) after acute spinal cord injury using an optimized multi-echo gradient-echo sequence. At 1-month after injury, preliminary results show lower grey matter volume in the conus medullaris. This is the first MRI investigation indicating remote tissue-specific volumetric changes in the conus medullaris in spinal cord injury.
Cord compression from stenosis reduces resting-state functional connectivity in the cervical spinal cord
Authors: Combes Anna , O'Grady Kristin , Rogers Baxter , Adesinasi Wuraola , Prock Logan , Houston Delaney , Shah Hamid , Edwards David , Chotai Silky , Stephens Byron , Chen Li Min , Smith Seth , Gore John
Published: August 2023

Spinal cord stenosis presents with highly variable clinical manifestations and prognoses. Resting-state functional MRI of the cord could provide complementary information in addition to structural measures. We sought to determine whether functional connectivity (FC) measures were altered in patients with compression of the lower cervical spinal cord, and whether those were related to morphometric measures at and above the level of pathology. Compression in the lower segments was significantly associated with lower FC of the ventral and dorsal networks in patients. This finding is a first step in exploring the FC features of the cord in compressive pathology.
Spinal cord fMRI heatmaps reveal a structured cardiac artifact “traveling” along the length of the cord
Authors: Hemmerling Kimberly , Hoggarth Mark , Parrish Todd , Bright Molly
Published: August 2023

Denoising of spinal cord fMRI data is important to address physiological noise confounds. Heatmaps used to visualize structured variance in spinal cord fMRI data reveal a unique artifact of aliased cardiac signals from pulsatile flow adjacent to the cord, which appears to travel along the longitudinal cord axis. Cardiac-related RETROICOR noise maps indicate that this artifact is successfully modeled and removed. The artifact velocity along the length of the spinal cord was calculated and is moderately correlated to the heart rate. This artifact may also provide insight into CSF flow in the spinal canal.
Comparison of cerebral oxygen extraction fraction using ASE and TRUST methods in patients with sickle cell disease and healthy controls
Authors: Fellah Slim , Ying Chunwei , Guilliams Kristin , Fields Melanie , Chen Yasheng , Lewis Joben , Mirro Amy , Cohen Rachel , Igwe Nkemdilim , Eldeniz Cihat , Jiang Dengrong , Lu Hanzhang , Lee Jin-Moo , Ford Andria , An Hongyu
Published: August 2023

We evaluated cerebral oxygen extraction fraction (OEF) in patients with sickle cell disease (SCD) and controls using two MR techniques: asymmetric spin echo (ASE) and T2-relaxation-under-spin-tagging (TRUST). We hypothesized that both methods would yield similar OEF and that TRUST-derived OEF would be elevated in patients with SCD vs. controls as previously found using ASE-derived OEF. ASE-derived and TRUST-derived OEF using the Lu 2012 calibration model showed a positive correlation (rho=0.823, p<0.001). Conversely, ASE-derived vs. TRUST-derived OEF using the Bush 2021 model showed a negative association (rho=-0.569, p<0.001). The directionality of these associations was heavily dependent on the calibration model used.
QTM Quantifies Velocity of Tumor Vasculature in Gliomas
Authors: Romano Dominick , Zhang Qihao , Kovanlikaya Ilhami , Chiang Gloria , Spincemaille Pascal , Wang Yi
Published: August 2023

A recently proposed perfusion analysis method, Quantitative Transport Mapping (QTM), was applied in malignant Glioma (grade III and IV) to obtain the flow speed map. Pathological lesions were separated into DCE-Enhancing, Darkening, and total affected ROIs. The average speed scalar for each ROI suggests that DCE-Enhancing tumor presents with significantly increased speed while non-enhancing tumor does not experience a speed change.
Narcosis depresses the BOLD-CVR response to acetazolamide in pediatric moyamoya vasculopathy
Authors: Deckers Pieter , Siero Jeroen , Kronenburg Annick , Braun Kees , van der Zwan Bart , Bhogal Alex
Published: August 2023

Measuring cerebrovascular reactivity (CVR) under narcosis is underreported, while narcosis is often necessary for pediatric or cognitively impaired patients. When acetazolamide is used in awake patients, maximum CBF increase reaches a plateau after ~12min. Using ASL- and BOLD-MRI with acetazolamide we showed that for pediatric moyamoya patients the response is different. Patients under narcosis show lower CVR and reach peak CBF earlier (after around six minutes), after which CBF decreases again without the plateau-phase. This shows the response to acetazolamide is distinctively different between awake and narcosis patients and caution is warranted during interpretation of narcosis CVR images.
Multi-parametric 18-FDG PET/MRI in predicting lung cancer lymphatic metastasis
Authors: Fu Fangfang , Nan Meng , Wu Yaping , Huang Zhun , Bai Yan , Feng Pengyang , Fang Ting , Yuan Jianmin , Yang Yang , Gao Haiyan , Wang Meiyun
Published: August 2023

It is meaningful to predict lymph node status of lung cancer before surgery. In the study, 18F-FDG PET/MRI were used to obtain PET metabolic parameters, multi-model DWI and APTWI parameters for predicting LNM of lung cancer. Our results showed that multiparametric PET/MRI is helpful in predicting lymph node status before surgery. 18F-FDG hybrid PET/MRI enables a robust diagnosis ability of LNM of lung cancer when several multi-model DWI parameters, PET metabolic parameters and APT parameter are combined. Thus, integrated PET/MRI can help to characterize LNM before surgery.
Motion Compensation in Pulmonary Ultra-short Echo Time MRI: Preliminary Results in Neonatal Bronchopulmonary Dysplasia
Authors: Torres Luis , Higano Nara , Gandhi Deep , Gunatilaka Chamindu , Woods Jason , Fain Sean
Published: August 2023

Self-gating of free breathing pulmonary MR images remains challenging due to inconsistent tidal breathing and bulk motion especially in neonatal patients. We evaluate several conventional and advanced retrospective motion compensation techniques in neonatal subjects with lung disease of prematurity. Registration-based techniques show a significant improvement in signal to noise ratio and contrast to noise ratio relative to other motion compensation methods. There were no significant changes in sharpness across the cohort. We conclude that registration-based techniques could be used to improve image quality without loss of sharpness.
Changes in Tibial Articular Cartilage T2 Relaxation Time with Load – An in vivo Repeatability Study
Authors: Sofko Katie , Elebute Ibukunoluwa , Cui Lumeng , Bzowey Natasha , McWalter Emily
Published: August 2023

Tibial articular cartilage plays the important role of transmitting forces through the knee joint; however, we most often study it without any applied loads. The aim of this work was to assess the repeatability of T2 relaxation time maps in the unloaded and loaded knees of five healthy participants. Using qDESS, it is possible to obtain repeatable, in vivo T2 relaxation time maps of the entire tibial cartilage surface as well as inside and outside regions of tibiofemoral contact in both unloaded and loaded knees.
The association of thigh muscle volume and fatty infiltration with knee joint structural damage
Authors: Pirmoazen Amir , Bharadwaj Upasana , Lynch John , Pedoia Valentina , Nevitt Michael , McCulloch Charles , Joseph Gabby , Link Thomas
Published: August 2023

Knee osteoarthritis results from inflammatory, mechanical, and metabolic processes, leading to chronic degenerative changes. The purpose of this study was to investigate the cross-sectional associations between thigh muscle volume or intermuscular fat volume, and relative muscle sizes, from T1-weighted MR images of 100 thighs, and radiographic knee osteoarthritis (ROA) using Kellgren-Lawrence grades. The results showed that lower volumes of the quadriceps and the anterior muscle compartment of the thigh relative to total muscle volume, as well as relative higher hamstring muscle volume were associated with presence of ROA (P<0.05).
GLCM texture analysis of knee cartilage T2 maps: machine learning based selection of important features
Authors: Janacova Veronika , Szomolanyi Pavol , Vilimek Dominik , Trattnig Siegfried , Juras Vladimir
Published: August 2023

Texture analysis of quantitative T2 maps in combination with machine learning was explored as a tool for classification and prediction of various conditions in musculoskeletal (MSK) research. We explored random forest classification algorithm as a tool for identification of important texture features for the classification of MACT grafts and native cartilage twelve months after surgery. Our model performed with high accuracy (84.6%) and identified features with highest importance were: cluster prominence, sum average, autocorrelation and correlation.
MRI Monitoring of Changes in Kidney Size during
Pathophysiological Intervention
Authors: Gladytz Thomas , Tasbihi Ehsan , Millward Jason , Cantow Kathleen , Hummel Luis , Periquito Joao , Waiczies Sonia , Seeliger Erdmann , Niendorf Thoralf
Published: August 2023

Several renal pathologies are associated with changes in kidney size, offering an opportunity for magnetic resonance imaging (MRI) biomarkers of disease. An automated bean-shaped model was developed for kidney size measurements in rats using parametric MRI (T2, T2* mapping). The ABSM approach was applied to longitudinal renal size quantification during pathophysiologically relevant interventions affecting kidney size. A precision and accuracy similar to manual segmentation was achieved allowing size changes of 2% to be detected reliably. This can potentially be instrumental for developing MRI-based diagnostic tools for various kidney disorders and for gaining new insight into mechanisms of renal pathophysiology.
Understanding T1 in heterogeneous systems: Extending the two-pool model to fractional order
Authors: Reynolds Luke , MacKay Alex , Michal Carl
Published: August 2023

Reliably quantifying longitudinal relaxation in heterogenous systems like white matter is challenging because measured parameters are sensitive to details of the measurement technique. In particular, cross-relaxation/magnetization exchange between aqueous and non-aqueous tissue components may lead to multi-exponential relaxation during inversion recovery, depending on the difference in the pools’ initial magnetizations. We use a generalization of the Bloch equations to fractional order to show that the additional component stemming from this exchange is better described by a stretched Mittag-Leffler function than a standard exponential in heterogenous systems. This approach may provide additional information about the material structure.
How modeling lactate diffusion may inform on its cellular compartmentation? An initial study
Authors: Malaquin Sophie , Valette Julien
Published: August 2023

Brain lactate compartmentation in neurons, astrocytes and the extracellular space is presumably of critical importance, but remains impossible to assess non-invasively. DW-MRS of lactate might capture lactate fractions in each compartment, provided these compartments induce different diffusion properties. Here we propose a framework where diffusion of cell-specific metabolites (Ins and NAA) is modeled to predict lactate diffusion in astrocytes and neurons. We use some “realistic” (spheres+cylinders) and simplified (cylinders) models of cell microstructure to show that lactate fractions in each compartment can be accurately estimated, despite inaccurate microstructure modeling. Models are finally tested on in vivo mouse brain data.
Characterization of relationship between MR microstructural parameters and memory in older subjects
Authors: Peltier Scott , Karker Michelle , Nielsen Jon-Fredrik , Seraji-Bozorgzad Navid , Paulson Henry , Giordani Bruno , Hampstead Benjamin
Published: August 2023

This work examined the relationship between white matter microstructure parameters calculated by NODDI and a composite measure of memory function. Connectome predictive modeling was done on fractional anisotropy, orientation dispersion, and neurite density maps. Significant relationships were found for all parameters, with orientation dispersion having the highest correlation between predicted and observed memory scores.
Microbleed detection in autopsied brains from community-based older adults using microbleed synthesis and deep learning
Authors: Nikseresht Grant , Tamhane Ashish , Javierre-Petit Carles , Evia Arnold , Bennett David , Schneider Julie , Agam Gady , Arfanakis Konstantinos
Published: August 2023

Automated cerebral microbleed (CMB) detection on ex-vivo MRI is key to enabling MRI-pathology studies in large community-based cohorts where manual CMB annotation is time consuming and prone to error. The aim of this study is to develop a CMB detection algorithm to aid in the quantization and localization of CMBs on ex-vivo T2*-weighted gradient echo MRI in community-based cohorts. A CMB synthesis algorithm is proposed and synthetic CMBs are used to train a neural network for CMB detection. A model trained with both synthetic and real data is shown to outperform models trained on synthetic or real data alone.
Multi-parametric versus bi-parametric prostate MRI for deep learning: Marginal benefits from adding dynamic contrast-enhanced images
Authors: Netzer Nils , Schrader Adrian , Görtz Magdalena , Schwab Constantin , Hohenfellner Markus , Schlemmer Heinz-Peter , Bonekamp David
Published: August 2023

The value of dynamic contrast enhanced MRI (DCE) for the diagnosis of prostate cancer is unclear and has not yet been investigated in the context of deep learning. We trained 3D U-Nets to segment prostate cancer on bi-parametric MRI and on DCE images of 761 exams. On a test set of 191 exams, the bi-parametric baseline achieved a ROC AUC of 0.89, showing a higher specificity that clinical PI-RADS at a sensitivity of 0.9. Additional improvement could be achieved by fusing bpMRI and DCE predictions, resulting in a ROC AUC of 0.9.
Towards Clinical Translation of Machine Learning-based Automated Prescription of Spine MRI Acquisitions
Authors: Ozhinsky Eugene , Liu Felix , Pedoia Valentina , Majumdar Sharmila
Published: August 2023

High quality scan prescription that optimally covers the area of interest with scan planes aligned to relevant anatomical structures is crucial for error-free radiologic interpretation. In this study we used images and metadata from previously acquired examinations of lumbar spine to train machine learning-based automated prescription models without the need of any manual annotation or feature engineering. The automated prescription pipeline was integrated with the scanner console software and evaluated in healthy volunteer experiments. This study demonstrates the feasibility of using oriented object detection-based pipelines on the scanner for automated prescription of lumbar spine acquisitions.
Predicted tumor stroma segmentation from high-field MR texture maps and machine learning: an ex vivo study on ovarian tumors
Authors: Tardieu Marion , Khellaf Lakhdar , Cardoso Maida , Sgarbura Olivia , Colombo Pierre-Emmanuel , Goze-Bac Christophe , Nougaret Stephanie
Published: August 2023

The objective was to probe the associations of high-field MR-images and their derived texture maps (TM) with histopathology in ovarian cancer (OC). Four ovarian tumors were imaged ex-vivo using a 9.4T-MR scanner. Automated MR-derived stroma-tumor segmentation maps were constructed using machine learning and validated against histology. Through TM, we found that areas of tumor cells appeared uniform on MR-images, while areas of stroma appeared heterogeneous. Using the automated model, MRI predicted stromal proportion with an accuracy from 61.4% to 71.9%. In this hypothesis-generating study, we showed that it is feasible to resolve histologic structures in OC using ex-vivo MR radiomics.
MRI-based liver vascular morphology and surface nodularity quantification for assessment of portal hypertension
Authors: Wang Yikun , Li Ruokun , Zhou Jiahao , Wang Chengyan , Yan Fuhua
Published: August 2023

Hepatic venous pressure gradient (HVPG) measurement is the standard technique of assessing portal pressure. Portal hypertension is mainly caused by increased intrahepatic resistance to portal blood flow related to structural changes, including fibrosis and vascular distortion. Here, we used dynamic contrast-enhancement (DCE) MRI to quantify segmented liver contours and vascular morphology in evaluating portal pressure. Our study showed the MRI measurements correlated well with HVPG measurement. A non-invasive prediction model combining liver vascular morphology and liver surface nodularity (LSN) can potentially be used to assess clinically significant portal hypertension (CSPH).
Effect of post mortem interval and body temperature on tissue susceptibility
Authors: Otsuka Fábio , Chaim Khallil , Otaduy Maria , Salmon Carlos
Published: August 2023

On this study, the impact of temperature and postmortem interval (PMI) on QSM were evaluated for a total of 21 subjects. Temperature and PMI were correlated with values from CSF, white matter (WM) and gray matter (GM). Only the GM presented a significant correlation with both temperature and PMI.
SNR and Field Strength with Small Surface Coils
Authors: Pohmann Rolf , Avdievitch Nikolai , Scheffler Klaus
Published: August 2023

The increase in SNR with higher field strength is one of the main drivers for ultra high field MRI. Here, the sensitivity gain is determined for phantoms in five different fields between 3 T and 14.1 T, using identical small surface coils and correcting for all scanner specific influences. A strong, more than quadratic SNR gain with increasing field strength was found, which applies to many animal studies and to measurements with weakly loading samples.
Human brain POCE MRS at 7T using a 13C birdcage coil and 8 transmit-receive 1H antennas with a 32-channel 1H receive array
Authors: Jacobs Sarah , Prompers Jeanine , van der Kemp Wybe , van der Velden Tijl , Gosselink Mark , Meliadò Ettore , Hoogduin Hans , Mason Graeme , de Graaf Robin , van der Kolk Anja , Alborahal Cezar , Klomp Dennis , Wiegers Evita
Published: August 2023

We have shown that it is feasible to perform POCE MRS in the human brain at 7T during a uniformly labeled [U-13C] glucose infusion in three healthy volunteers, using a 13C birdcage head coil combined with 8 transmit-receive 1H antennas with a 32-channel 1H receive array. STEAM-POCE and sLASER-POCE provided similar sensitivity for the [4-13C]-Glx-H4 signals. POCE examinations could be performed in two locations, i.e. the frontal and occipital lobe, in one session, allowing them to be easily merged with 1H MRI.
Simulation validation of an 8-channel parallel-transmit dipole array: including RF losses for robust correlation with experimental results
Authors: Clément Jérémie , Ipek Özlem
Published: August 2023

A method for validation of the simulation model with respect to experimental results is introduced for an 8-channel parallel-transmit dipole coil array. An original approach to include RF losses is described. The simulation results were quantitatively compared to the experimental data in terms of scattering parameters, individual transmit field (magnitude/phase) and combined transmit field. Two distinct configurations, not including RF losses were compared to the proposed approach. High correlation was achieved between simulated and experimental data. We conclude that with the proposed approach for RF losses, a robust validation is achieved for the 8-channel parallel-transmit dipole coil array at 7T.