Magnetic Strength Research Articles

Polarized neutron imaging at NeXT (neutron and x-ray tomograph) at Institut Laue Langevin.

This work describes the implementation of polarized neutron imaging capabilities at the neutron and x-ray tomograph (NeXT) imaging station of the Institut Laue Langevin. This development enhances the capacity of this instrument to study advanced magnetic materials, which are crucial in a variety of engineering applications. Here, the feasibility of polarized neutron imaging at NeXT is demonstrated by visualizing the magnetic field generated by a simple bar magnet. The use of a double-crystal monochromator for wavelength-resolved imaging is also shown to enable both quantitative and qualitative analyses of magnetic materials. This is demonstrated through the determination of magnetization strength in a sample of electric steel (FeSi) in addition to the distribution of its components. Polarimetric imaging is also implemented for the first time to characterize the magnetic field generated by a current-carrying cylindrical wire. These findings collectively underscore the value of incorporating polarized neutron imaging into the already cutting-edge imaging station.

Fabrication, characterization, spectroscopic, and magnetic properties of polyaniline/magnetite (PANi/Fe3O4) nanocomposites

In this research, pure polyaniline (PANi), pure magnetite (Fe3O4), and then PANi/ Fe3O4 nanocomposites were prepared and characterized. FT-IR spectra of the prepared samples indicate successful polymerization of PANi onto Fe3O4. PANi/Fe3O4 nanocomposites exhibit broad absorption bands at specific wavenumbers, indicating the presence of various functional groups. The observed blue shift in certain peaks suggests the interaction between nitrogen atoms and oxygen atoms on the magnetite surface through hydrogen bonding. The intensity and wavenumber of the Fe3O4 band decrease, indicating weakened Fe–O bonds. These findings demonstrate a strong interaction and combination between PANi and Fe3O4 in the nanocomposites. Fe3O4 nanoparticles exhibit a regular spherical shape with an average diameter of 16 nm. However, they also show non-uniform size distribution due to aggregation into larger secondary particles, likely driven by attractive forces. PANi/Fe3O4 core-shell nanocomposites demonstrate clear morphological changes, with Fe3O4 nanoparticles well spread and wrapped by the PANi shell. The electron diffraction technique confirms the crystalline structure of Fe3O4 nanoparticles, showing diffraction rings consistent with magnetite. The results confirm the potential of incorporating magnetic Fe3O4 nanoparticles to impart magnetic functionality in the resulting PANi-based nanocomposite materials. Magnetic saturation measurements displayed an enhancement in magnetization with increasing Fe3O4 nanoparticles. The change in magnetic behavior for doped samples provides a means of tuning the magnetization strength of the composites to meet the application requirement such as data storage and magnetic sensors.

Passivity-Based Control with Disturbance Observer of Electromagnetic Formation Flight Spacecraft in the Port-Hamiltonian Framework

Satellite formation flying technology currently represents a focal point in space mission research. Traditional spacecraft payload performance and lifespan are often constrained by propellant limitations. Electromagnetic Formation Flying (EMFF), a propellant-free formation flying technique, has garnered widespread attention. Its inherent strong nonlinearity and coupling present challenges for high-precision control within EMFF. This paper presents the relative motion dynamics of a two-satellite EMFF in the port-Hamiltonian framework and constructs an accurate nonlinear model of the dynamics. Utilizing the concept of Interconnection and Damping Assignment and nonlinear disturbance observer, a composite disturbance-rejection passivity-based controller is designed, offering a method for controlling the magnetic dipole strength of formation satellites. Finally, numerical simulations are conducted to demonstrate the viability of the proposed dynamics model and control strategy.

Evaluation of the Biological Effects of Exposures to Magnetic Resonance Imaging on Single-Strand DNA: An In-vivo Study

Introduction: Magnetic resonance imaging (MRI) is a powerful diagnostic technique used to acquire detailed information on the structure and function of the body’s organs. Data on the extent of genetic damage following exposure to electromagnetic fields in MRI is variable, necessitating further evidence. This study aims to examine the biological effect of exposure to MRI at various magnetic strengths on the DNA single-strand. Methods: The study was an in-vivo non-randomized controlled experiment involving New Zealand rabbits (n=39, males) scanned using three different MRI strengths (0.5, 1.5 and 3.0 T) and at different time intervals (10, 20, 30, and 40 minutes). The alkaline comet assay was used to study DNA damage by quantifying single-strand breaks. In addition, tail length (TL), tail moment (TM), and the fraction of total DNA in the tail were evaluated. Results: The DNA single-strand breaks were significant for all tested parameters in both MRI 1.5 T (p<0.01) and 3.0 T (p<0.001). In addition, 3.0 T for 40 minutes had the most comet tails and tail moment (13.87), resulting in greater %DNA damage (mean=22.37). Exposure to 0.5 T was found to be only significant at 30 and 40 minutes (p<0.001). Conclusion: Higher MRI strength for a longer duration resulted in a significant increase in DNA single-strand breaks. Understanding the interaction between the magnetic fields generated by MRI and DNA will optimize safe and effective MRI scanning in both patients and healthy individuals.

Robust prostate disease classification using transformers with discrete representations.

Automated prostate disease classification on multi-parametric MRI has recently shown promising results with the use of convolutional neural networks (CNNs). The vision transformer (ViT) is a convolutional free architecture which only exploits the self-attention mechanism and has surpassed CNNs in some natural imaging classification tasks. However, these models are not very robust to textural shifts in the input space. In MRI, we often have to deal with textural shift arising from varying acquisition protocols. Here, we focus on the ability of models to generalise well to new magnet strengths for MRI. We propose a new framework to improve the robustness of vision transformer-based models for disease classification by constructing discrete representations of the data using vector quantisation. We sample a subset of the discrete representations to form the input into a transformer-based model. We use cross-attention in our transformer model to combine the discrete representations of T2-weighted and apparent diffusion coefficient (ADC) images. We analyse the robustness of our model by training on a 1.5 T scanner and test on a 3 T scanner and vice versa. Our approach achieves SOTA performance for classification of lesions on prostate MRI and outperforms various other CNN and transformer-based models in terms of robustness to domain shift and perturbations in the input space. We develop a method to improve the robustness of transformer-based disease classification of prostate lesions on MRI using discrete representations of the T2-weighted and ADC images.

A Practical Hybrid Hysteresis Model for Calculating Iron Core Losses in Soft Magnetic Materials

Accurately calculating the losses of ferromagnetic materials is crucial for optimizing the design and ensuring the safe operation of electrical equipment such as motors and power transformers. Commonly used loss calculation models include the Bertotti empirical formula and hysteresis models. In this paper, a new hybrid hysteresis model method is proposed to calculate losses—namely, the combination of the Jiles–Atherton hysteresis model (J–A) and the Fourier hysteresis model. The traditional Jiles–Atherton hysteresis model is mainly suitable for fitting the saturation hysteresis loop, but the fitting error is relatively large for internal minor hysteresis loops. In contrast, the Fourier hysteresis model is suitable for fitting the minor hysteresis loops because the corresponding magnetic induction strength or magnetic field is lower and the waveform distortion is small. Moreover, Fourier series expansion can be expressed with fewer terms, which is convenient for parameter fitting. Through examples, the results show that the hybrid hysteresis model can take advantage of the strengths of each model, not only reducing computational complexity, but also ensuring high fitting accuracy and loss calculation accuracy.

Effect of Magnetic Strength of the Water Salinity Treatment Devices on Salt Accumulation in the Root Zoon and Its Impact on Growth and Productivity of Olive Trees

This study was conducted during the two successive seasons 2022 and 2023 at Wadi El-Natron west Nile Delta (EL-Behera governorate) to evaluate three commercial magnetic devices “Water magnetizers” of different manufacturers (Nefertari Biomagnetic 6000 Gauss, Magnolith 8000 Gauss, Delta Water 14000 Gauss), and to figure out which is more effective to reduce the negative effect of irrigating olive trees with saline water. The study examined the effect on vegetative growth, leaf mineral contents, leaf chlorophyll content, leaf proline content, and relative water content of Manzanillo olive trees. The experiment confirmed that olive trees can be irrigated with water containing 3500 ppm without causing high salt stress. Data also showed a positive effect of magnetically treated water on all vegetative growth characters (growth rate, stem diameter, number of green leaves), an increase in all elements content in experimental plant leaves except sodium and chloride, an increase in leaf chlorophyll content, decreased leaf proline content and increase relative water content. In terms of determining whether commercial devices are more effective than others, the Magnolith has been demonstrated to achieve the best results when compared to other devices, in most cases the difference between using "Delta Water" or "Nefertari" was not big enough to be significant. "Nefertari" recorded almost the lowest values of the studied vegetative growth characters, leaf chlorophyll, and relative water content. This indicates that the strength of the magnets alone is not the only thing that affects how well the device works; furthermore, it depends also on how the magnetic fields are configured and the manufacturing expertise.

Enhancing purity and crystallinity of carbon nanotubes by magnetically assisted arc discharge and thermal purification and their field emission characteristics

This study used a magnetically assisted arc discharge (AD) method and thermal purification to enhance the purity and crystallinity of multi-walled carbon nanotubes (MWCNTs). CNT synthesis in the presence of a magnetic field increased the densities of ionic carbon species and the arc plasma temperature, thereby improving CNT production. AD-MWCNTs produced at an optimal magnetic strength exhibited enhanced purity, crystallinity, and thermal stability. Thermal purification was also conducted to increase the purity of the AD-MWCNTs further. Purity was evaluated using Raman spectroscopy. AD-MWCNTs were homogenized to overcome limitations in light-penetration depths to ensure accurate evaluation. The calculated purities were consistent with the analytical results, confirming the reliability of Raman spectroscopy for purity assessment. The number of working CNT emitters on the film surface was directly related to the purity. Highly pure crystalline AD-MWCNTs exhibited high-performance field-emission properties, namely a high current density of 2.7 A/cm2 and long-term emission stability (12 h at a current density of 500 mA/cm2), with no performance reduction.

Towards Preventing Anastomotic Leakage through the “No-perforation Virtual Staples”

Anastomotic leakage (AL) is a severe postoperative complication after gastrointestinal surgery, potentially leading to morbidity and mortality. The factors contributing to AL include poor blood flow to the suture line, tension, infection, underlying conditions, and surgeon-related factors. However, the stress concentration, which is a localized increase in stress due to discontinuities caused by sutures or staples, has often been overlooked. The working hypothesis is that by removing problematic stresses and simulating mechanical loadings on the anastomosis, improved recommendations for stapler design, surgical technique, and anastomotic construction can be derived to reduce the occurrence of leaks. The objective of this study is to develop and optimize "no-perforation" magnetic staples that can effectively minimize stress and prevent AL. In this study, magnet-metal bar couples coated with a biocompatible adhesive hydrogel were utilized to replace existing surgical staples. By employing magnetic forces, the tissue was deformed into a curved shape, which provided additional security for the new "magnetic staples". This technique aimed to eliminate complications such as high tension and poor blood flow often associated with traditional staples. To ensure safety, a double protection system consisting of the pectin adhesive (previously patented at BWH) and the "lock-in forces" of the magnetic staples was implemented. It was believed that relying solely on adhesion would not effectively prevent leaks. Preliminary data indicated that applying virtual staples for anastomoses was feasible. The primary innovation of this approach is the substantial reduction in stress concentration when the anastomosis is under tension. The conventional surgical teaching concerning bowel anastomoses has centered on the dangers posed by excessive tension and compromised blood supply. In contrast, virtual staples offer the advantage of adjustable shape and force, allowing for optimization of tension and blood supply. The study successfully identified the biomechanical forces and stress concentrations that contribute to anastomotic leaks and developed new "virtual staples" to address this issue. The new "virtual staples" are made of two magnetic compression rings crafted from medical-grade silicone and feature 8 strategically embedded magnets. These rings are engineered with a specific surface curvature to ensure optimal axial alignment and elimination of stress concentrations. Cases for delivery have also been designed and fabricated, which are compatible with standard commercial delivery devices used in surgical settings. This ensures a seamless integration into existing medical procedures and surgical workflows. Initial in-vitro experiments were conducted on sections of the porcine intestine to test the effectiveness of the Virtual Staples. These preliminary tests have shown promising results, including an absence of leakage at the joined or sealed tissue sites. Our research aims to predict the stress concentration sites in tissues and evaluate the effects of applying adhesive virtual staples under new conditions. Through a combination of experiments and simulations, we designed non-perforation staples and optimized the design by considering various factors such as staple size, shape, magnet strength, and stress distribution. Initial in-vitro experiments indicated the effectiveness of the design. With further optimization of the design, along with animal testing and clinical trials, this new technique has the potential to revolutionize surgical procedures. The MA Acorn Innovation Grant 2023. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Residual stress analysis of plasma sprayed coatings through the weak magnetic field testing method

A proposed technique for swiftly evaluating coating stress variations involves utilizing weak magnetic detection under geomagnetic field conditions. This method examines the surface magnetic induction strength on uncoated test specimens, analyzing the magnetic induction change pre- and post-spraying. Employing the Almen test method, the assessment of specimen deflection and residual stress magnitude affirms the viability of weak magnetic detection for assessing coating residual stress. The experimental findings establish a direct link between the rate of magnetic induction intensity change and residual stress magnitude through polynomial fitting, suggesting that weak magnetic detection can preliminarily analyze coating stress variation.

Magnetic polyamide 11 powder for the powder bed fusion process by liquid-liquid phase separation and crystallization

Herein, we demonstrate the preparation of magnetic polyamide 11 feedstock powders for powder bed fusion (PBF) using liquid-liquid phase separation and crystallization. By adding magnetic nanomaterials during the precipitation process, the particulate additive is incorporated into the polymer matrix. This enables the production of filled systems at single particle level, which is advantageous in terms of the adjustable magnetic strength and homogeneity of the powder. Thermogravimetric analysis is used to determine the additive content and onset temperature of decomposition of composite powders, where additive-enhancement of PA11 powders with magnetic iron oxide nanoparticles showed a positive influence on the thermal stability of the feedstock. Successive analysis of particle size distribution, shape, colour, crystal structure, magnetic properties and thermal properties of the composite powders are carried out and their properties are discussed with respect to the PBF process. A decrease in particle size, width of the thermal process window and isothermal crystallization time can be attributed to the nucleating effect of the magnetic additive. The PBF processability of the composite feedstock is demonstrated by the production of magnetic tensile bar specimens from additive-enhanced PA11 powders with 1 wt.-% magnetic iron oxide.

Compressive Strength Analysis of Mortar Made from Volcanic Sand in Nagari Aia Angek Based on Magnetic Mineral Content

Compressive strength testing is carried out on mortar made from a mixture of sand, cement and water. Mortar is one of the construction materials in building structures that has the main function as a material for construction parts. The compressive strength test is useful for measuring and knowing the strength of objects against compressive forces. The method used in this research is rock magnetism to determine the abundance of magnetic minerals and compressive strength testing to determine the relationship of compressive strength results to the magnetic minera content of Nagari Aia Angek volcanic sand. Volcanic sand is measured using a Bartington Susceptibility Meter Type MS2B with 3 forms of mineral separation treatment, namely Magnetic Mineral Reduction (PMM) with a value of χlf 505,99 x10 m-83 /kg, χfd (%) 2.72%, Additional Magnetic Minerals (TMM) with a value of χlf 1026.72 x10 m-83 /kg, χfd (%) 2.14%, and No Treatment (TP) with a value of χlf 853.98 x10 m-83 /kg, χlf (%) 2.16. The results of testing the compressive strength of mortar using Compression Testing Mechine on 3 volcanic sand treatments were obtained (PMM) with a value of 169.14 kg/cm2, (TMM) with a value of 147.11 kg/cm2, and (TP) with a value of 141.81 kg/cm2. The magnetic properties of volcanic sand samples are antiferrimagnetic and have superparamagnetic mixed grains and coarse grains. There is a relationship between the compressive strength value of mortar and the concentration of magnetic minerals, the higher the compressive strength value, the higher the χfd (%) value obtained

Reduced Right Hippocampal Volume on MRI and Correlation with Major Depressive Disorder

Introductions: Many studies have shown in the field of psychiatry results in specific changes in brain anatomy and function associated with measurable clinical outcomes. One of the biggest difficulties in diagnosing and treating psychiatric disorders is that human behavior involves complex mechanisms when compared to experimental animals. Case: 25-year-old female, diagnosed with Major Depressive Disorder (MDD) 6 months ago at a General Hospital in Malang, Indonesia. The patient felt depressed, had trouble sleeping, and had attempted suicide. MRI of the hippocampus was performed at the power of 3 Tesla magnetic strength (PHILIPS INGENIA 3.0T). MRI data processing and hippocampal volumetric analysis were performed using the volBrain HIPS software. Discussion: The left hippocampus volume was larger than the right volume, with a history of the patient never doing exercise or exercising regularly. In general, the hippocampus can be asymmetrical on both sides and larger on the right side. Although asymmetry in the hippocampus is normal, but there are no studies that say the volume of the left hippocampus is larger than the volume of the right hippocampus in a normal people. Conclusions: a person with depression should be screened and planned for early treatment. In the field of radiology, psychoradiology plays an important role in the main clinical situation in guiding decisions, especially treatment planning, as well as monitoring the results of care carried out in patients with psychiatric disorders.

Effect of magnetic induction intensity and steel fiber rate on strength improvement of cementitious filling composites

The underhand cut-fill backfill mining manner (UCFBMM) is widely employed in nonferrous metallic mines, and stability of the artificial backfill top plate directly determines the safety of operators and equipment, which puts forward higher requirements on fill’s bending properties. The purpose of the current research is to advance steel-fiber reinforced cemented tailings backfills’ (SFCTBs’) mechanical features by employing steel fibers. 17 groups of specimens were prepared by considering the effects of diverse steel fiber doping and magnetic induction strength on SFCTB’s bending properties. Steel fiber reinforced SFCTB’s bending evolution was studied by utilizing three-point bending tests, SEM interpretations, and X-ray computed tomography. Lab findings exhibited that directional distribution of steel fibers was effective in increasing SFCTB’s flexural strength, and the flexural strength was positively correlated with fiber doping and magnetic induction strength. The presence of steel fibers and their directional distribution well inhibited crack development, and thus the crack resistance and toughness of SFCTBs, enabling them to bear greater tensile force. The unadulterated steel fiber reinforced SFCTBs showed sudden fracture when reaching the peak load, while the steel fiber adducted SFCTB specimens showed the characteristics of good ductility. Due to gravity and magnetism, steel fibers were distributed at the bottom of SFCTBs and showed a directional distribution along the length of the specimens. Besides, SFCTBs produced further CSH-gels and Aft in process of hydration. The overall outcomes of the current study could run an academic guide to construction of artificial backfilling roofs in UCFBMM in terms of cost and operational stages.

New YAC time-fractional derivative approach for water-based hydromagnetic chemically reacting radiative flow of nanofluid with copper nanoparticles past an upright plate

The current article utilizes the novel application of the Yang-Abdel-Cattani (YAC) fractional derivative to analyze the Casson nanofluid flow. Water nanofluid suspended with copper nanoparticles is considered in the flow phenomenon. Primarily, the dimensionless governing equations are converted to a fractional model by using a new description of fractional derivative, i.e. YAC fractional derivative. These fractional equations are then transformed and solved using the Laplace method. Finally, the solutions of these transformed equations are obtained in terms of a series of Prabhakar functions. The comparative results for Newtonian and non-Newtonian fluids are obtained using the analytical solutions and presented in the form of graphs. The effect of the chemical reaction, Casson parameter, radiation parameter, orders of the time-fractional derivative, and magnetic strength on velocity, temperature, and concentration fields is investigated. The fluid behavior of both Newtonian and Casson fluids is analyzed and presented in the form of graphs. Fluid temperature is enhanced by 5.22% with the use of copper nanoparticles with a 4% volume fraction. With the advancement of chemical reaction, the velocity and concentration of the nanofluid are observed to be decreasing.

Fe3O4-Cy5.5-trastuzumab magnetic nanoparticles for magnetic resonance/near-infrared imaging targeting HER2 in breast cancer

This study developed a probe Fe3O4-Cy5.5-trastuzumab with fluorescence and magnetic resonance imaging functions that can target breast cancer with high HER2 expression, aiming to provide a new theoretical method for the diagnosis of early breast cancer. Fe3O4-Cy5.5-trastuzumab nanoparticles were combined with Fe3O4 for T2 imaging and Cy5.5 for near-infrared imaging, and coupled with trastuzumab for HER2 targeting. We characterized the nanoparticles used transmission electron microscopy, hydration particle size, Zeta potential, UV and Fourier transform infrared spectroscopy, and examined its magnetism, fluorescence, and relaxation rate related properties. CCK-8 and blood biochemistry analysis evaluated the biosafety and stability of the nanoparticles, and validated the targeting ability of Fe3O4-Cy5.5 trastuzumab nanoparticles through in vitro and in vivo cell and animal experiments. Characterization results showed the successful synthesis of Fe3O4-Cy5.5-trastuzumab nanoparticles with a diameter of 93.72 ± 6.34 nm. The nanoparticles showed a T2 relaxation rate 42.29 mM−1s−1, magnetic saturation strength of 27.58 emg g−1. Laser confocal and flow cytometry uptake assay showed that the nanoparticles could effectively target HER2 expressed by breast cancer cells. As indicated by in vitro and in vivo studies, Fe3O4-Cy5.5-trastuzumab were specifically taken up and effectively aggregated to tumour regions with prominent NIRF/MR imaging properties. CCK-8, blood biochemical analysis and histological results suggested Fe3O4-Cy5.5-trastuzumab that exhibited low toxicity to major organs and good in vivo biocompatibility. The prepared Fe3O4-Cy5.5-trastuzumab exhibited excellent targeting, NIRF/MR imaging performance. It is expected to serve as a safe and effective diagnostic method that lays a theoretical basis for the effective diagnosis of early breast cancer. This study successfully prepared a kind of nanoparticles with near-infrared fluorescence imaging and T2 imaging properties, which is expected to serve as a new theory and strategy for early detection of breast cancer.

Brain MRI sequence and view plane identification using deep learning.

Brain magnetic resonance imaging (MRI) scans are available in a wide variety of sequences, view planes, and magnet strengths. A necessary preprocessing step for any automated diagnosis is to identify the MRI sequence, view plane, and magnet strength of the acquired image. Automatic identification of the MRI sequence can be useful in labeling massive online datasets used by data scientists in the design and development of computer aided diagnosis (CAD) tools. This paper presents a deep learning (DL) approach for brain MRI sequence and view plane identification using scans of different data types as input. A 12-class classification system is presented for commonly used MRI scans, including T1, T2-weighted, proton density (PD), fluid attenuated inversion recovery (FLAIR) sequences in axial, coronal and sagittal view planes. Multiple online publicly available datasets have been used to train the system, with multiple infrastructures. MobileNet-v2 offers an adequate performance accuracy of 99.76% with unprocessed MRI scans and a comparable accuracy with skull-stripped scans and has been deployed in a tool for public use. The tool has been tested on unseen data from online and hospital sources with a satisfactory performance accuracy of 99.84 and 86.49%, respectively.

Synthesis of rGO/CoFe2O4 Composite and Its Magnetorheological Characteristics.

In this study, composite particles of rGO/CoFe2O4 were synthesized using a solvothermal method to fabricate a low-density magnetorheological (MR) material with enhanced sedimentation stability. The morphology and crystallographic features of rGO/CoFe2O4 were characterized via SEM, TEM, and XRD, and its magnetic properties were tested using VSM. The MR fluid was formulated by blending rGO/CoFe2O4 particles into silicone oil. Under different magnet strengths (H), a rotational rheometer was used to test its MR properties. Typical MR properties were observed, including shear stress, viscosity, storage/loss modulus, and dynamic yield stress (τdy) following the Herschel-Bulkley model reaching 200 Pa when H is 342 kA/m. Furthermore, the yield stress of the MR fluid follows a power law relation as H increases and the index changes from 2.0 (in the low H region) to 1.5 (in the high H region). Finally, its MR efficiency was calculated to be about 104% at H of 342 kA/m.

Impact of SUSAN Denoising and ComBat Harmonization on Machine Learning Model Performance for Malignant Brain Neoplasms.

Feature variability in radiomics studies due to technical and magnet strength parameters is well-known and may be addressed through various preprocessing methods. However, very few studies have evaluated the downstream impact of variable preprocessing on model classification performance in a multiclass setting. We sought to evaluate the impact of Smallest Univalue Segment Assimilating Nucleus (SUSAN) denoising and Combining Batches harmonization on model classification performance. A total of 493 cases (410 internal and 83 external data sets) of glioblastoma, intracranial metastatic disease, and primary CNS lymphoma underwent semiautomated 3D-segmentation post-baseline image processing (BIP) consisting of resampling, realignment, coregistration, skull-stripping, and image normalization. Post-BIP, 2 sets were generated, one with and another without SUSAN denoising. Radiomics features were extracted from both data sets and batch-corrected to produce 4 data sets: (a) BIP, (b) BIP with SUSAN denoising, (c) BIP with Combining Batches, and (d) BIP with both SUSAN denoising and Combining Batches harmonization. Performance was then summarized for models using a combination of 6 feature-selection techniques and 6 machine learning models across 4 mask-sequence combinations with features derived from 1 to 3 (multiparametric) MRI sequences. Most top-performing models on the external test set used BIP+SUSAN denoising-derived features. Overall, the use of SUSAN denoising and Combining Batches harmonization led to a slight but generally consistent improvement in model performance on the external test set. The use of image-preprocessing steps such as SUSAN denoising and Combining Batches harmonization may be more useful in a multi-institutional setting to improve model generalizability. Models derived from only T1 contrast-enhanced images showed comparable performance to models derived from multiparametric MRI.

Cardiovascular Magnetic Resonance Reference Ranges From the Healthy Hearts Consortium

BackgroundThe absence of population-stratified cardiovascular magnetic resonance (CMR) reference ranges from large cohorts is a major shortcoming for clinical care. ObjectivesThis paper provides age-, sex-, and ethnicity-specific CMR reference ranges for atrial and ventricular metrics from the Healthy Hearts Consortium, an international collaborative comprising 9,088 CMR studies from verified healthy individuals, covering the complete adult age spectrum across both sexes, and with the highest ethnic diversity reported to date. MethodsCMR studies were analyzed using certified software with batch processing capability (cvi42, version 5.14 prototype, Circle Cardiovascular Imaging) by 2 expert readers. Three segmentation methods (smooth, papillary, anatomic) were used to contour the endocardial and epicardial borders of the ventricles and atria from long- and short-axis cine series. Clinically established ventricular and atrial metrics were extracted and stratified by age, sex, and ethnicity. Variations by segmentation method, scanner vendor, and magnet strength were examined. Reference ranges are reported as 95% prediction intervals. ResultsThe sample included 4,452 (49.0%) men and 4,636 (51.0%) women with average age of 61.1 ± 12.9 years (range: 18-83 years). Among these, 7,424 (81.7%) were from White, 510 (5.6%) South Asian, 478 (5.3%) mixed/other, 341 (3.7%) Black, and 335 (3.7%) Chinese ethnicities. Images were acquired using 1.5-T (n = 8,779; 96.6%) and 3.0-T (n = 309; 3.4%) scanners from Siemens (n = 8,299; 91.3%), Philips (n = 498; 5.5%), and GE (n = 291, 3.2%). ConclusionsThis work represents a resource with healthy CMR-derived volumetric reference ranges ready for clinical implementation.