Magnetic Resonance Imaging Device Research Articles

Restoration of magnetohydrodynamic-corrupted 12-lead electrocardiogram to enhance cardiac monitoring during magnetic resonance imaging

The Magnetohydrodynamic (MHD) effect on the bloodstream, induced by the static magnetic field of Magnetic Resonance Imaging (MRI) devices, distorts Electrocardiogram (ECG) components, and poses challenges to cardiac gating and monitoring during MRI examinations. Restoring ECG components from MHD-induced artifacts has always been a challenge, primarily due to the influence of numerous device-induced and physiological variables and the absence of paired ground truth clean ECG for validation. In this research, at first, we employ unpaired restoration of MHD-corrupted 12-lead ECG signals using one dimensional (1D) Cycle Generative Adversarial Networks (CycleGANs) for channel and patient orientation-specific restoration. Subsequently, a 1D-segmentation-based comprehensive restoration scheme is proposed based on the phase 1 outputs to simultaneously restore 12-channel ECG signals, irrespective of internal and external factors affecting ECG. By employing the proposed Magnetohydrodynamic Generative Adversarial Network (MHDGAN) and MHD-to-ECG Network (MHD2ECGNet) for unpaired and comprehensive restoration, we achieved an overall spectral correlation improvement of 92.56% and 77.64%, respectively. In R-peak detection, MHDGAN demonstrated an overall precision, recall, and F1-score of 98.14%, 94.12%, and 96.01%, respectively. The extracted heart rate (HR) and heart rate variability (HRV) from the restored waveforms closely match the ground truth, as confirmed through quantitative and qualitative assessments. The proposed framework has proven effective in restoring MHD-corrupted ECG waveforms, even in the absence of paired ground truth labels and amidst compounding distortions from multiple sources.

Radiofrequency-Induced Heating of Amalgam Restorations and Dental Implants During 1.5T Magnetic Resonance Imaging

Objectives: This study aimed to evaluate radiofrequency-induced heating of different amalgam restorations and dental implants during 1.5T magnetic resonance imaging (MRI). Materials and Methods: Standardized class I cavities (5 mm long, 3 mm wide, and 3 mm deep) were prepared on the occlusal surface of 45 extracted human third molars. The samples were restored by three different types of amalgam including Cinalux amalgam (non-gamma-2, spherical), GS-80 (non-gamma-2, admix), and GK-110 amalgam (non-gamma-2, admix in silver). As a separate intervention group (G4), five titanium mini drive-lock implants with 2mm diameter and 10mm length were also selected and mounted to the base of the Eppendorf tube with 3mm of the implants extending above the mounting putty. The box containing the specimens was placed parallel to the long axis of the standard head and neck coil of the MRI device (64MHz radio-frequency energy with 25kW amplifier, 1.5T). Temperature fluctuations of the metallic materials in each group were monitored during MRI scans using a calibrated thermometer. One-way ANOVA was used to compare temperature changes among the amalgam groups (P<0.05). Results: Temperature elevations ranged from 0.21°C to 0.70°C in amalgam restorations and from 0.35 to 0.47°C in dental implants. The temperature changes among the three amalgam agents were not statistically significant. Conclusion: According to our findings, the radiofrequency-induced heating of amalgam restorations and dental implants during MRI examination can be considered within acceptable ranges. Therefore, amalgam restorations and dental implants can be categorized as "MR safe" in terms of radiofrequency-induced heating during 1.5 T MRI.

Revisiting the Young’s model for ferrofluid droplets: Magnetowetting or magneto-dewetting?

Magnetic field-mediated wetting of ferrofluid droplets has emerged to be of fundamental importance because of its plethora of applications ranging from chemical and biomolecular analysis to soft robotics and medical imaging. However, while extensive studies continue to be reported on the underlying experimental facets, a fundamental theoretical depiction of the observed contact angle variation with the applied magnetic field remains grossly elusive, as attributable to a complex dependence of the induced magnetization on the droplet’s intrinsic magnetic properties. Circumventing these constraints, here we put forward a first-principle analytical model that delineates the variation in the contact angle as a function of an applied magnetic field on a sessile ferrofluid droplet, by appealing to energy minimization principles. One key feature of our analysis is the consideration of the local magnetization as a function of the magnetic field itself, resulting in a new contribution to the interfacial energy by virtue of normal traction at the droplet's contact with its non-magnetic surroundings. This theory is supported by experiments identified in prior research to elucidate the fundamental physics of relevance. Our results highlight the substantial influence of the saturation magnetization and the initial susceptibility of the ferrofluid on the resulting contact angle alterations, as well as possible non-trivial routes of highly selective and precise enhancement or attenuation in the extent of wetting. These findings are likely to be of fundamental importance towards establishing the design foundations of portable magnetic resonance imaging devices, micromixers, and microreactors, magnetically-manipulated automatic control of soft fluidic matters, among others.

Synthesis, structural, optical, dielectric, magnetic and magneto-dielectric properties of CoFe2O4 and Graphene Quantum Dots (GQDs) decorated CoFe2O4 hybrid nanocomposite

A sol-gel synthesis method was used for the synthesis of pure CoFe2O4 (CFO) as well as Graphene Quantum Dots (GQDs) decorated CoFe2O4 Hybrid Nanocomposite (GCHN). From X-ray diffraction (XRD) data it was analyzed that both these samples have a cubic structure with Fd-3m space group. Using Debye-Scherer's equation, the average sizes were determined to be 24.48 and 13.74 nm, respectively. FTIR spectra revealed details about vibration bands and functional groups present. Raman spectra confirmed existence of GQDs in GCHN with an ID/IG ratio of ∼0.8. The results of Field emission scanning electron microscopy (FESEM) analysis exhibited microstructural morphological details having shapes of grains to be non-uniform in shape. UV–visible data was used to calculate band gap (Eg) energy by using Tauc plot method and found to be 2.52 eV and 2.99 eV respectively for CFO and GCHN. Urbach energy (EU) was found to be 1.03 and 1.19 eV for CFO and GCHN respectively. The dielectric properties of GCHN were analyzed for dependence on frequency and temperature and explained by Maxwell-Wagner-type polarization. The frequency-dependent ac conductivity (σac) followed Jonscher's power law and investigated dynamics of ion hopping. Impedance spectroscopy was used to further evaluate Nyquist plots with respect to temperature as well as magnetic fields to estimate grain and grain boundary contributions. This was further used to evaluate electrical characteristics such as relaxation time (τ). Activation energies (Ea) calculated using relaxation times were found to be 0.48 eV for CFO while 0.22 and 0.92 eV for GCHN respectively. At room temperature, CFO and GCHN exhibited a strong magneto-dielectric coupling (MD) and showed negative magneto-dielectric properties in low-frequency regions. At room temperature (RT), magnetization values of CFO and GCHN displayed were 38.48 and 7.52 emu/g respectively. The lower magnetization value was possibly due to shielding by GQDs in GCHN. These properties enable it to be used as a potential application in microelectronic systems, spintronics, optical and optoelectronic devices, magnetic resonance imaging (MRI) and memory devices.

Content-aware Nakagami morphing for incremental brain MRI

Within the carcinogenesis mechanism, from the initiation of the very first tumor cell to the preneoplastic and neoplastic cancer cell groups, cancer cells omnidirectionally and unpredictably proliferate in three-dimensional (3D) space during the promotion and progression steps. Whole tumors areas, consisting of edema, necrosis, enhancing and non-enhancing tumor subareas, could easily be identified by the typical sequences of magnetic resonance imaging (MRI), mostly by FLAIR, the fluid attenuated inversion recovery sequence. Depending on the increment value of the scanner, not every scan could be contiguous though, which might create some gaps between the slices and cause some crucial loss of information. Shape-based morphing by erosion and dilation operations might be inadequate when the source or target lesions are not found on the MRI slices, which might emerge due to unpredictable shape of tumors. Furthermore, the real trajectories and genuine shapes of the tumors in spatial view might not be seen in the planar MRI slices due to approximations during the voxel-to-pixel transformations executed in MRI devices. Therefore, we propose a novel content-aware morphing procedure to generate imaginary slices by m-parametric Nakagami imaging. The mathematical and parametric design in our framework not only leads to precise segmentation of the whole tumors according to the ground truth images; but also, to realistic morphing, based on the content of tumor footprints in MRI slices. For testing purposes, a total number of 5133 morphs are created using 1831 genuine images containing at least one lesion taken from the Brats 2012 dataset. Given the average dice score coefficients (DSC), we obtained an average of 88.44% DSC with our morphing framework outperforming the conventional dilation-based morphing result which is 83.25%. Besides being a novel morphing methodology, the outcomes of this research could also be very beneficial in smoother 3D reconstruction and more realistic volumetric calculations of lesions to help the experts working on assessment of lesions.

Brain tumor detection from images and comparison with transfer learning methods and 3-layer CNN

Health is very important for human life. In particular, the health of the brain, which is the executive of the vital resource, is very important. Diagnosis for human health is provided by magnetic resonance imaging (MRI) devices, which help health decision makers in critical organs such as brain health. Images from these devices are a source of big data for artificial intelligence. This big data enables high performance in image processing classification problems, which is a subfield of artificial intelligence. In this study, we aim to classify brain tumors such as glioma, meningioma, and pituitary tumor from brain MR images. Convolutional Neural Network (CNN) and CNN-based inception-V3, EfficientNetB4, VGG19, transfer learning methods were used for classification. F-score, recall, imprinting and accuracy were used to evaluate these models. The best accuracy result was obtained with VGG16 with 98%, while the F-score value of the same transfer learning model was 97%, the Area Under the Curve (AUC) value was 99%, the recall value was 98%, and the precision value was 98%. CNN architecture and CNN-based transfer learning models are very important for human health in early diagnosis and rapid treatment of such diseases.

Deep learning application for abdominal organs segmentation on 0.35 T MR-Linac images.

Linear accelerator (linac) incorporating a magnetic resonance (MR) imaging device providing enhanced soft tissue contrast is particularly suited for abdominal radiation therapy. In particular, accurate segmentation for abdominal tumors and organs at risk (OARs) required for the treatment planning is becoming possible. Currently, this segmentation is performed manually by radiation oncologists. This process is very time consuming and subject to inter and intra operator variabilities. In this work, deep learning based automatic segmentation solutions were investigated for abdominal OARs on 0.35 T MR-images. One hundred and twenty one sets of abdominal MR images and their corresponding ground truth segmentations were collected and used for this work. The OARs of interest included the liver, the kidneys, the spinal cord, the stomach and the duodenum. Several UNet based models have been trained in 2D (the Classical UNet, the ResAttention UNet, the EfficientNet UNet, and the nnUNet). The best model was then trained with a 3D strategy in order to investigate possible improvements. Geometrical metrics such as Dice Similarity Coefficient (DSC), Intersection over Union (IoU), Hausdorff Distance (HD) and analysis of the calculated volumes (thanks to Bland-Altman plot) were performed to evaluate the results. The nnUNet trained in 3D mode achieved the best performance, with DSC scores for the liver, the kidneys, the spinal cord, the stomach, and the duodenum of 0.96 ± 0.01, 0.91 ± 0.02, 0.91 ± 0.01, 0.83 ± 0.10, and 0.69 ± 0.15, respectively. The matching IoU scores were 0.92 ± 0.01, 0.84 ± 0.04, 0.84 ± 0.02, 0.54 ± 0.16 and 0.72 ± 0.13. The corresponding HD scores were 13.0 ± 6.0mm, 16.0 ± 6.6mm, 3.3 ± 0.7mm, 35.0 ± 33.0mm, and 42.0 ± 24.0mm. The analysis of the calculated volumes followed the same behavior. Although the segmentation results for the duodenum were not optimal, these findings imply a potential clinical application of the 3D nnUNet model for the segmentation of abdominal OARs for images from 0.35 T MR-Linac.

Tomografia computadorizada e ressonância magnética no Brasil: estudo epidemiológico sobre distribuição dos equipamentos, frequência de realização dos exames e comparação entre setores público e privado

Abstract Objective: To compare information on highly complex radiological procedures—computed tomography (CT) and magnetic resonance imaging (MRI)—between the public and private health care systems, across the five regions of Brazil, in terms of the numbers of radiological devices and examinations performed, between 2015 and 2021. Materials and Methods: This was a descriptive time series analysis of secondary data in the public domain, available from the Information Technology Department of the Brazilian Unified Health Care System, an entity of the Brazilian National Ministry of Health (NMH) that is responsible for collecting and storing health-related information in Brazil. The analysis included the numbers of CT and MRI scanners; the volumes and types of examinations; the type of institution (public or private); the regions of the country; and the years (2015 to 2021). Results: Progressive increases in the numbers of CT and MRI devices, as well as in the volumes of examinations, were observed over the years in all regions of the country. The private sector showed higher rates of equipment acquisition and of growth in the number of examinations. However, the public health care system did not reach the equipment targets set by the NMH, whereas the private health care system surpassed those targets. A greater number of examinations were performed in the private sector than in the public sector. Conclusion: During the period evaluated, the public health care system did not meet the equipment or examination targets recommended by the NMH, in any of the regions of the country, unlike the private health care system, which exceeded both in all of the regions.

A Comparative Diagnostic Study for Using the Contrast Agent in Active and Non-Active Multiple Sclerosis by Region of Interest Parameter

Background: Multiple sclerosis (MS) is a neuropathological disease diagnosed by a magnetic resonance imaging device. Early patients affected with MS are named active. Objectives: This study assessed the difference between active and non-active MS using the region of interest value. Methods: Twenty patients with MS included in this study were examined with T1 weighted image (T1W) with and without contrast agent injection to increase the brightness of darker regions after only 10 minutes. Also, T2 weighted images (T2W) and Fluid-attenuated inversion recovery (FLAIR) were scanned. The area of interest option was calculated for all cases. Results: The result shows that the region of interest (ROI) value was significantly higher for T1 weighted image (T1W) with contrast than without. Furthermore, the range of FLAIR values was higher than the (T2W). Conclusion: The ROI is an effective parameter for diagnosing active MS early by values instead of the radiographic picture.

A deep learning model to generate synthetic CT for prostate MR-only radiotherapy dose planning: a multicenter study

IntroductionFor radiotherapy based solely on magnetic resonance imaging (MRI), generating synthetic computed tomography scans (sCT) from MRI is essential for dose calculation. The use of deep learning (DL) methods to generate sCT from MRI has shown encouraging results if the MRI images used for training the deep learning network and the MRI images for sCT generation come from the same MRI device. The objective of this study was to create and evaluate a generic DL model capable of generating sCTs from various MRI devices for prostate radiotherapyMaterials and methodsIn total, 90 patients from three centers (30 CT-MR prostate pairs/center) underwent treatment using volumetric modulated arc therapy for prostate cancer (PCa) (60 Gy in 20 fractions). T2 MRI images were acquired in addition to computed tomography (CT) images for treatment planning. The DL model was a 2D supervised conditional generative adversarial network (Pix2Pix). Patient images underwent preprocessing steps, including nonrigid registration. Seven different supervised models were trained, incorporating patients from one, two, or three centers. Each model was trained on 24 CT-MR prostate pairs. A generic model was trained using patients from all three centers. To compare sCT and CT, the mean absolute error in Hounsfield units was calculated for the entire pelvis, prostate, bladder, rectum, and bones. For dose analysis, mean dose differences of D99% for CTV, V95% for PTV, Dmax for rectum and bladder, and 3D gamma analysis (local, 1%/1 mm) were calculated from CT and sCT. Furthermore, Wilcoxon tests were performed to compare the image and dose results obtained with the generic model to those with the other trained models.ResultsConsidering the image results for the entire pelvis, when the data used for the test comes from the same center as the data used for training, the results were not significantly different from the generic model. Absolute dose differences were less than 1 Gy for the CTV D99% for every trained model and center. The gamma analysis results showed nonsignificant differences between the generic and monocentric models.ConclusionThe accuracy of sCT, in terms of image and dose, is equivalent to whether MRI images are generated using the generic model or the monocentric model. The generic model, using only eight MRI-CT pairs per center, offers robust sCT generation, facilitating PCa MRI-only radiotherapy for routine clinical use.

Analysis of Heart Pulse Transmission Parameters Determined from Multi-Channel PPG Signals Acquired by a Wearable Optical Sensor

Abstract The article describes the development and testing of a special prototype wearable device consisting of three optical photoplethysmography (PPG) sensors. The functionality of the developed triple PPG sensor was tested under normal laboratory conditions and in a running magnetic resonance imaging (MRI) scanner working with a low magnetic field. The results of the first measurements under normal laboratory conditions show that the obtained mutual positions of systolic/diastolic blood pressure values and heart pulse transmission parameters determined from the PPG waves can be fitted by a line segment with a sufficiently high slope. Measurement experiments inside the open-air MRI tomograph show the practical influence of vibrations and acoustic noise on the cardiac system of the examined persons, which was confirmed by a slight increase in the heart pulse rate and changes in pulse transmission time and pulse wave velocity. We plan to perform further measurements inside the whole-body MRI device producing more intensive vibrations and noise with expected higher stress impact on an exposed person.

The Application of Deep Learning to Electroencephalograms, Magnetic Resonance Imaging, and Implants for the Detection of Epileptic Seizures: A Narrative Review.

Epilepsy is a neurological disorder characterized by recurrent seizures affecting millions worldwide. Medically intractable seizures in epilepsy patients are not only detrimental to the quality of life but also pose a significant threat to their safety. Outcomes of epilepsy therapy can be improved by early detection and intervention during the interictal window period. Electroencephalography is the primary diagnostic tool for epilepsy, but accurate interpretation of seizure activity is challenging and highly time-consuming. Machine learning (ML) and deep learning (DL) algorithms enable us to analyze complex EEG data, which can not only help us diagnose but also locate epileptogenic zones and predict medical and surgical treatment outcomes. DL models such as convolutional neural networks (CNNs), inspired by visual processing, can be used to classify EEG activity. By applying preprocessing techniques, signal quality can be enhanced by denoising and artifact removal. DL can also be incorporated into the analysis of magnetic resonance imaging (MRI) data, which can help in the localization of epileptogenic zones in the brain. Proper detection of these zones can help in good neurosurgical outcomes. Recent advancements in DL have facilitated the implementation of these systems in neural implants and wearable devices, allowing for real-time seizure detection. This has the potential to transform the management of drug-refractory epilepsy. This review explores the application of ML and DL techniques to Electroencephalograms (EEGs), MRI, and wearable devices for epileptic seizure detection. This review briefly explains the fundamentals of both artificial intelligence (AI) and DL, highlighting these systems' potential advantages and undeniable limitations.

MRI surveillance after translabyrinthine vestibular schwannoma resection and cochlear implantation: is it feasible?

PurposeCochlear implantation in patients with vestibular schwannomas is of increasing importance and interest. Two remaining challenges are the assessment of conduction of the cochlear nerve and the possibility of postoperative surveillance with magnetic resonance imaging. The aim of the current study was to assess follow-up imaging and determine the visibility of the internal auditory canal after vestibular schwannoma resection and cochlear implantation as well as in patients with persistent vestibular schwannomas and cochlear implants in place. Visibility of the internal auditory canal, cerebellopontine angle, and labyrinth were evaluated and graded.MethodsFor this retrospective study, 15 MR examinations of 13 patients after translabyrinthine vestibular schwannoma resection and ipsilateral cochlear implantation were included. All patients had been implanted with an MED-EL cochlear implant. Magnetic resonance imaging was carried out on a 1.5T device. All patients were prepped according to the manufacturer’s recommendations.ResultsAll 15 examinations were carried out without any adverse event during imaging, such as pain, magnet dislocation, or malfunction. The internal auditory canal and the cerebellopontine angle were sufficiently visible in all cases to allow for vestibular schwannoma follow-up.ConclusionMagnetic resonance imaging surveillance of the internal auditory canal following vestibular schwannoma resection and cochlear implantation is feasible and safe with modern implants with a 1.5T magnetic resonance imaging device using metal artifact reduction sequences. Necessary follow-up imaging should not be a contraindication for cochlear implantation in patients with vestibular schwannomas.

Effect of external magnetic field on realistic bifurcated right coronary artery hemodynamics

Diagnostic technology based on magnetic fields is commonly used in medicine for diagnosis and therapy. However, the exposure to strong electromagnetic fields has adverse outcomes in patients. Thus, the objective of the current study is to investigate the effect of applying external uniform magnetic fields on the blood flow in both healthy and diseased cases of right coronary artery and determine the safe values of the applied magnetic field strengths. The diseased cases include a 40% stenosed artery along with two blood disorder cases with a hematocrit level of 20% and 60%. A comprehensive three-dimensional steady non-Newtonian flow model is developed using the Casson model to investigate the effect of the magnetic field on both shear rate and hematocrits. The model is numerically simulated at different values of magnetic field strengths and its orientation. The results indicated that the magnetic field in the Y-direction has a dominant effect compared to other directions. Moreover, the maximum increase in the main branch mass flow rate fraction is about 6.2%. Another interesting finding is that the wall shear stress is slightly affected by the magnetic field strength. For the stenosed case, it is found that the high magnetic field strengths can reduce the formulation of the vortices and hence reduce the risk of thrombosis, which agrees with published works. Additionally, the obtained results confirm that using a magnetic field up to 11.7 T, which is used in magnetic resonance imaging devices, is safe, and has a slight effect on blood flow parameters such as the wall shear stress.

Technique for Performing Magnetic Resonance Imaging (MRI) of the Cervical Spine at the Mali Hospital

Introduction: Magnetic Resonance Imaging is one of the non-invasive or irradiating medical imaging techniques. MRI explores with precision the organs and soft tissues, in the different planes of space (2 to 3 Dimensions). In patients with neurological signs suggestive of cervical spinal cord compression, MRI is the reference examination, even normal CT and X-rays. Objective: To highlight the technique of performing MRI of the cervical spine in patients admitted to the Medical Imaging department of the Mali hospital. Method: This was a prospective and descriptive study that took place from October to December 2018. The MRI device used is low field (0.35T) and open. This study included 23 patients who had undergone MRI of the cervical spine. Results: These different methodologies enabled us to obtain the results of 23 patients. The male sex was more represented with 60.87% against the female sex or 39.13%. Among the most common reasons, paralysis is 52.17% of our examinations carried out. The average age was 47 years with extremes ranging from 16 to 75 years. The most represented age group in our series was 46 to 55 years or 30.43%. These results confirm the relationship between cervical pathologies and professional activities, men being the most active in Mali. MRI examinations of the cervical spine were 23, out of 165, or 07%. Conclusion: MRI has revolutionized the imaging of the cervical spine as this technique proves to be complete and efficient for the study of all the anatomical structures of the spine, of which it allows the most precise diagnostic assessment. Despite the low capacity of the installation and the lack of people trained in its implementation, the technique meets the standards of implementation and produces quality diagnoses with the assistance of radiologists.

MRI safety for leave-on powdered hair thickeners under 1.5-T and 3.0-T MRI: measurement of deflection force, MRI artifact, and evaluation of preexamination screening.

This study aimed to clarify the magnetic resonance imaging (MRI) compatibility of leave-on powdered hair thickeners by evaluating the displacement force and image artifacts of commercially available leave-on powdered hair thickeners on MRI devices and their response to metal and ferromagnetic detectors. Thirteen types of leave-on powdered hair thickeners were studied: nine hair thickener and four foundation types. MRI systems of 1.5T and 3.0T were used. Deflection angles and MR image artifacts according to ASTM F2052 and F2119 were evaluated. Handheld metal and ferromagnetic detectors were used to investigate whether hair thickeners could be detected in screening before MRI examinations. The hair thickener type had a deflection angle of 0°, whereas the foundation type had a deflection angle of 90°, indicating a strong physical effect. Significant image artifacts appeared only on the foundation type. The foundation type reacted at distances of less than 10cm only with a ferromagnetic detector. Foundation-type leave-on powdered hair thickeners containing magnetic substances exhibited strong physical effects and produced significant image artifacts, and those can only be detected by screening with a ferromagnetic detector.

Linguoculturology and the Linguistic Picture of the World through the Neuropsychological Prism

The authors consider linguoculturology through the science of neuropsychology. They define and clarify the concepts necessary for the review of linguoculturology and the linguistic picture of the world through neuroscience, which can reveal the impact of culture and language on human consciousness. The problem is that the research on unconscious processes is not sufficiently widely disclosed and remains little studied. The goal is to identify the relationship between language and cultural concepts that most effectively affect the human subconscious. The tasks are to determine the relationship between culture and language through the neuropsychological prism of response triggers; to consider the manifestation of culture, which is reflected in the language, in unconscious - psychic suggestion; to establish the interdependence of national-specific features of the genesis of the linguistic worldview through ambivalent concepts. The relevance lies in the growing attention of the international community on the correlation of truth and “fake”, acceptance and rejection, as well as a broad interest in the field of neuropsychology. The methodology of this work is a descriptive review of EEG (electroencephalogram), MRI (magnetic resonance imaging), and sound recording devices. The main conclusions. Human triggers (triggers) are inseparable from culture, language, and communication methods that lead to a narrowed perception of one’s own response. The manifestation of culture is reflected in the language, influences the people’s perceptions and their beliefs, where suggestion affects human consciousness.

Advanced Radio Frequency Applicators for Thermal Magnetic Resonance Theranostics of Brain Tumors

Thermal Magnetic Resonance (ThermalMR) is a theranostic concept that combines diagnostic magnetic resonance imaging (MRI) with targeted thermal therapy in the hyperthermia (HT) range using a radiofrequency (RF) applicator in an integrated system. ThermalMR adds a therapeutic dimension to a diagnostic MRI device. Focused, targeted RF heating of deep-seated brain tumors, accurate non-invasive temperature monitoring and high-resolution MRI are specific requirements of ThermalMR that can be addressed with novel concepts in RF applicator design. This work examines hybrid RF applicator arrays combining loop and self-grounded bow-tie (SGBT) dipole antennas for ThermalMR of brain tumors, at magnetic field strengths of 7.0 T, 9.4 T and 10.5 T. These high-density RF arrays improve the feasible transmission channel count, and provide additional degrees of freedom for RF shimming not afforded by using dipole antennas only, for superior thermal therapy and MRI diagnostics. These improvements are especially relevant for ThermalMR theranostics of deep-seated brain tumors because of the small surface area of the head. ThermalMR RF applicators with the hybrid loop+SGBT dipole design outperformed applicators using dipole-only and loop-only designs, with superior MRI performance and targeted RF heating. Array variants with a horse-shoe configuration covering an arc (270°) around the head avoiding the eyes performed better than designs with 360° coverage, with a 1.3 °C higher temperature rise inside the tumor while sparing healthy tissue. Our EMF and temperature simulations performed on a virtual patient with a clinically realistic intracranial tumor provide a technical foundation for implementation of advanced RF applicators tailored for ThermalMR theranostics of brain tumors.

Design of a double acting pneumatic cartilage loading device for magnetic resonance imaging

Studies of osteoarthritis initiation and progression that measure strain in cartilage require physiological loading levels. Many studies use magnetic resonance (MR) imaging, which necessitates a MR-compatible loading device. In this study, the design and validation of a new device, the cartilage compressive actuator (CCA), is presented. The CCA is designed for high-field (e.g., 9.4 T) small-bore MR scanners, and meets a number of design criteria. These criteria include capability for testing bone-cartilage samples, MR compatibility, constant load and incremental strain application, a water-tight specimen chamber, remote control, and real time displacement feedback. The mechanical components in the final design include an actuating piston, a connecting chamber, and a sealed specimen chamber. An electro-pneumatic system applies compression, and an optical Fibre-Bragg grating (FBG) sensor provides live displacement feedback. A logarithmic relationship was observed between force exerted by the CCA and pressure (R2 = 0.99), with a peak output force of 653 ± 2 N. The relationship between FBG sensor wavelength and displacement was linear when calibrated both outside (R2 = 0.99) and inside (R2 = 0.98) the MR scanner. Average slope was similar between the two validation tests, with a slope of −4.2 nm/mm observed inside the MR scanner and −4.3 to −4.5 nm/mm observed outside the MR scanner. This device meets all design criteria and represents an improvement over published designs. Future work should incorporate a closed feedback loop to allow for cyclical loading of specimens.

MaRCoS, an open-source electronic control system for low-field MRI

Every magnetic resonance imaging (MRI) device requires an electronic control system that handles pulse sequences and signal detection and processing. Here we provide details on the architecture and performance of MaRCoS, a MAgnetic Resonance COntrol System developed by an open international community of low-field MRI researchers. MaRCoS is inexpensive and can handle cycle-accurate sequences without hard length limitations, rapid bursts of events, and arbitrary waveforms. It has also been readily adapted to meet the requirements of the various academic and private institutions participating in its development. We describe the MaRCoS hardware, firmware and software that enable all of the above, including a Python-based graphical user interface for pulse sequence implementation, data processing and image reconstruction.