MR Technology Research Articles

Dream-Experiment: A MR User Interface with Natural Multi-channel Interaction for Virtual Experiments.

This paper studies a set of MR technologies for middle school experimental teaching environments and develops a multi-channel MR user interface called Dream-Experiment. The goal of Dream-Experiment is to improve the traditional MR user interface, so that users can get a real, natural 3D interactive experience like real experiments, but without danger and pollution. In terms of visual presentation, we design multi-camera collaborative registration to realize robust 6-DoF MR interactive space, and also define a complete rendering pipeline to provide improved processing of virtual-real objects' occlusion including translucent devices. In the virtual-real interaction, we provide six interaction modes that support visual interaction, tangible interaction, virtual-real gestures with touching, voice, thermal feeling, and olfactory feeling. After users' testing, we find that Dream-Experiment has better interactive efficiency and user experience than traditional MR environments.

Advances in MR Technology

Advances in MR Technology

7T MR Safety.

Magnetic resonance imaging and spectroscopy (MRI/MRS) at 7T represents an exciting advance in MR technology, with intriguing possibilities to enhance image spatial, spectral, and contrast resolution. To ensure the safe use of this technology while still harnessing its potential, clinical staff and researchers need to be cognizant of some safety concerns arising from the increased magnetic field strength and higher Larmor frequency. The higher static magnetic fields give rise to enhanced transient bioeffects and an increased risk of adverse incidents related to electrically conductive implants. Many technical challenges remain and the continuing rapid pace of development of 7T MRI/MRS is likely to present further challenges to ensuring safety of this technology in the years ahead. The recent regulatory clearance for clinical diagnostic imaging at 7T will likely increase the installed base of 7T systems, particularly in hospital environments with little prior ultrahigh-field MR experience. Informed risk/benefit analyses will be required, particularly where implant manufacturer-published 7T safety guidelines for implants are unavailable. On behalf of the International Society for Magnetic Resonance in Medicine, the aim of this article is to provide a reference document to assist institutions developing local institutional policies and procedures that are specific to the safe operation of 7T MRI/MRS. Details of current 7T technology and the physics underpinning its functionality are reviewed, with the aim of supporting efforts to expand the use of 7T MRI/MRS in both research and clinical environments. Current gaps in knowledge are also identified, where additional research and development are required. Level of Evidence 5 Technical Efficacy 2 J. MAGN. RESON. IMAGING 2021;53:333-346.

Extended reality technology – a new component in industrial engineering and production systems

Extended (virtual, augmented and mixed) reality technology gets considered as a new universal component of production (industrial) engineering’s methodological basis, receiving the possibilities for wide use in both extensive and intensive development of carrying and other branches of the fourth, fifth and the forming nucleus of the sixth technological wave. The article gives grounds for the role and place of this kind of technology in contemporary technological processes and production systems (including the flexible, small-volume and discrete production), and in the context of cyberphysical systems and the incoming fourth industrial revolution. The authors describe underline the set of tasks that are universal for a wide range of branches in any national economy, that can be most efficiently completed in terms of the current and prognosed level of development of man-machine interaction can be provided for as a result of using VR, AR and MR technologies. Based on the comparison of implementation principles and examples of applied implementation, the article gives grounds for term correspondence and opportunities of use of “extended reality technology”. The authors have made and explained the conclusion on practicability of integrating extended reality technology based on a universal hardwaresoftware complex that provides VR, AR and MR services corresponding to the composition of a given task within the technological process or the operating mode chosen by a user. The article gives descriptions of task assignments, terms of conduct and results of experiments on designing and testing extended reality interactive environments performed at the institute of information technology RTU MIREA in 2019–2020.

Augmented, virtual and mixed reality in spinal surgery: A real-world experience.

This review aims to identify the role of augmented, virtual or mixed reality (AR, VR or MR) technologies in setting of spinal surgery. The authors address the challenges surrounding the implementation of this technology in the operating room. A technical standpoint addresses the efficacy of these imaging modalities based on the current literature in the field. Ultimately, these technologies must be cost-effective to ensure widespread adoption. This may be achieved through reduced surgical times and decreased incidence of post-operative complications and revisions while maintaining equivalent safety profile to alternative surgical approaches. While current studies focus mainly on the successful placement of pedicle screws via AR-guided instrumentation, a wider scope of procedures may be assisted using AR, VR or MR technology once efficacy and safety have been validated. These emerging technologies offer a significant advantage in the guidance of complex procedures that require high precision and accuracy using minimally invasive interventions.

Patient preparation and image quality in female pelvic MRI: recommendations revisited.

To assess whether with recent MR technology current patient preparation literature recommendations for female pelvic MRI are still valid and how they are influencing the position of the female pelvic organs, image quality, and diagnostic confidence. This prospective study was performed in two centres. The effects of bladder filling (empty, moderate, full; n = 26), fasting, saturation band (n = 25), and menstrual cycle (n = 25) were assessed in healthy subjects in centre 1, while the effect of intravenous glucagon application was evaluated in 20 patients with benign conditions in centre 2. Images of the pelvis were acquired using 1.5-T MRI with T2-weighted turbo spin echo imaging in sagittal and (angulated) transaxial planes. The analysis was conducted hierarchically using paired Wilcoxon tests with an alpha significance level of 0.05. Urinary bladder filling influenced the cervix-to-uterine angle (p < 0.001) but had no clear effect on image quality (p > 0.05). A moderately full bladder provided the best delineation of fat between the bladder and uterus (p = 0.0009). A full bladder resulted in highest ovarian displacement (p = 0.0059). Timing within the menstrual cycle did not influence the depiction of zonal anatomy (p > 0.05). Fasting (p < 0.02) and saturation bands (p < 0.001) had a positive effect on image quality. Glucagon was associated with decreased MRI artefacts (p = 0.002). Fasting, antispasmodic agents, and saturation bands improved MR image quality and are recommended for female pelvic MRI. Urinary bladder filling influenced the cervix-to-uterine angle, but had no clear effect on image quality. • Fasting, saturation band, and glucagon injection significantly reduced bowel movement artefacts. • Depiction of the anatomical details of the uterus was not influenced by the timing of MRI within the menstrual cycle. • Although bladder filling did not impact diagnostic capabilities in healthy volunteers, in clinical practice, it may be useful to examine patients with a moderately full bladder, to reduce diagnostic inaccuracies.

استخدام تکنولوجیا الواقع المعزز (AR) والواقع المختلط (MR) بالصحافة الإلکترونیة عبر المستحدثات التقنیة

استخدام تکنولوجیا الواقع المعزز (AR) والواقع المختلط (MR) بالصحافة الإلکترونیة عبر المستحدثات التقنیة

Mixed Reality and 3D Printed Models for Planning and Execution of Face Transplantation.

The aim of this study was to evaluate a novel holographic craniofacial surgical planning application and its implementation throughout the planning and operative stages of facial transplantation by performing a critical analysis of comparative utility, cost, and limitations of MR and 3D printing. Face transplantation is a highly complex form of craniofacial reconstruction requiring significant planning, knowledge of patient-specific spatial relationships, and time-sensitive decision making. Computer-aided 3D modeling has improved efficiency and outcomes of complex craniofacial reconstruction by enabling virtual surgical planning and 3D printed model generation. MR technology can enhance surgical planning, improve visualization, and allow manipulation of virtual craniofacial biomodels within the operative field. Accounting for the time-sensitive nature of face transplantation, a unique, highly coordinated workflow for image acquisition and processing was designed to facilitate rapid holographic rendering and 3D printing. During recent face transplantation, both holographic and 3D printed models were utilized, and the time and cost of fabrication were compared. Holographic models required less time and cost for fabrication. They provided both comprehensive visualization of 3D spatial relationships and novel means to perform VSP and virtual face transplantation by interacting with and manipulating patient-specific, anatomic holograms. Time efficiency, low-cost biomodel production, provision of unlimited preoperative surgical rehearsal, and potential for intraoperative surgical guidance makes holographic VSP and MR highly promising technology for use in complex craniofacial surgery.

Digital technologies in the industry: application of immersive training technologies in the oil and gas complex

The article substantiates the need to apply training and retraining programs for personnel for permanent work in the Arctic using digital technologies, namely VR / AR / MR technologies. The geopolitical features of the Arctic zone, difficult climatic conditions do not allow directly practicing the development of professional competencies and, therefore, require the introduction of a multi-stage system of personnel training using technologies of approximate reality. Such requirements for the personnel training system predetermine the need to search for relevant digital technologies that can create conditions that are as close as possible to the conditions of professional activity in hard-to-reach Arctic regions. When forming a personnel training / retraining system for oil and gas enterprises, in addition to the specified specific working conditions, it is also necessary to take into account the sectoral features of oil and gas enterprises, which also forms a number of functional requirements for the selection of relevant digital tools, the main of which for personnel training can be considered immersive technologies. Based on the above, the paper analyzes the use of immersive technologies by oil and gas enterprises, a comparative analysis of the directions of using immersive technologies in personnel training at oil and gas enterprises, identifies the positive and negative aspects of using VR / MR / AR technologies.

Shoulder MRI in diagnostic evaluation of shoulder joint instability: A comparison with shoulder arthroscopy

Background: Shoulder joint is an extremely mobile joint with reduced stability. Pain and discomfort due to shoulder joint instability is common cause of orthopedic referrals in young individuals. Diagnostic Arthroscopy is the gold standard in evaluation and planning of definitive repair surgeries. Recent advancements in MR technology with increased accessibility of the general population to MR facilities have enabled non-invasive detection of pathologies associated with shoulder instability. The present study was aimed at determining the diagnostic value of shoulder MRI in shoulder instability as compared to arthroscopy.Materials and Methods: MRI and subsequent arthroscopic evaluation of 182 patients with shoulder pain and instability admitted to a busy orthopedic referral center was done after performing adequate clinical examination and necessary investigations. Results: Sensitivity and specificity of MRI was 95.87% & 89.41%, for detection of Bankart’s lesion, 98.24% & 93.24% respectively for Hill Sach’s lesion and 86.36% & 97.37% respectively for SLAP tears. High sensitivity and specificity was also found for rotator cuff tears.Conclusion: MRI can give an adequate information with regards to the pathology involved in shoulder instability and can help provide valuable input in planning of repair surgeries and can very well help to avoid unnecessary arthroscopic procedure.

Extending the frontiers of neuroimaging: an introduction to Diffusion Tensor Imaging Tractography

Summary: The use of Diffusion Tensor Imaging (DTI) tractography has exploded over the past two decades, proving to be a major advancement in the current methods for exploring the architecture of white matter tracts in the living human brain. Despite making up 50% of brain tissue, investigations into the function of white matter have long remained in the background of medical research. Consequently, white matter pathology cited in neuropsychiatric disease remains a heavy burden of human illness. Nonetheless, with novel diffusion MRI techniques, including DTI tractography, we are able to visualise areas of the brain better than ever before, furthering our understanding of white matter beyond the crude depictions offered by conventional MRI. Relevance: It is important that medical students have an understanding of DTI tractography because it has the potential to illuminate mechanisms that underpin cognition and emotion through the creation of connectional maps. Furthermore, advances in MR technology should not be restricted to the territory of academics. Instead, both medical students and clinicians should be able to draw upon the current research methods to improve the care and understanding of patients with white matter pathology. Take Home Messages: 1. Diffusion Tensor Imaging is a diffusion MRI technique that depicts the movement of water molecules along major white matter pathways in the living brain. 2. Using information from DTI, tractography software virtually reconstructs white matter tracts and can be used to make dissections of major fasciculi in vivo. 3. DTI tractography remains the only non-invasive method to study white matter tracts in the living human brain. 4. Results from tractography are increasingly being used in neuropsychiatric research. 5. Despite its potential, DTI tractography still faces a number of challenges. The most prominent of these being its inability to accurately map crossing fibres within a voxel.

PKP Assisted With MR Technology in OVCF With IVC

PKP Assisted With MR Technology in OVCF With IVC

Mixed Reality Visualizations of Urban Data

As a consequence of inexpensive sensors, ubiquitous tracking devices, and abundant digital storage, by 2019 smarter cities have become platforms for increasing levels of operational monitoring and data capture. Various government agencies and private interests have generated a tremendous database of urban content, which, despite its availability, remains comprehensively inaccessible. How can new emerging MR technologies relate urban big data back to the physical and spatial conditions of the cities to which they relate? This paper examines data-integrated virtual urban environments, identifies their audience, determines their mechatronic configurations, and reviews strengths and limitations of use before presenting an experimental MR technology interface for translating urban data into accessible information.

Validation of MR technology for medical engineering applications

Validation of MR technology for medical engineering applications

Automatic localization of the subthalamic nucleus on patient-specific clinical MRI by incorporating 7 T MRI and machine learning: Application in deep brain stimulation.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has shown clinical potential for relieving the motor symptoms of advanced Parkinson's disease. While accurate localization of the STN is critical for consistent across-patients effective DBS, clear visualization of the STN under standard clinical MR protocols is still challenging. Therefore, intraoperative microelectrode recordings (MER) are incorporated to accurately localize the STN. However, MER require significant neurosurgical expertise and lengthen the surgery time. Recent advances in 7 T MR technology facilitate the ability to clearly visualize the STN. The vast majority of centers, however, still do not have 7 T MRI systems, and fewer have the ability to collect and analyze the data. This work introduces an automatic STN localization framework based on standard clinical MRIs without additional cost in the current DBS planning protocol. Our approach benefits from a large database of 7 T MRI and its clinical MRI pairs. We first model in the 7 T database, using efficient machine learning algorithms, the spatial and geometric dependency between the STN and its adjacent structures (predictors). Given a standard clinical MRI, our method automatically computes the predictors and uses the learned information to predict the patient-specific STN. We validate our proposed method on clinical T2 W MRI of 80 subjects, comparing with experts-segmented STNs from the corresponding 7 T MRI pairs. The experimental results show that our framework provides more accurate and robust patient-specific STN localization than using state-of-the-art atlases. We also demonstrate the clinical feasibility of the proposed technique assessing the post-operative electrode active contact locations.

Research and technology

The 2017/18 annual MR technology report reveals key opportunities for research companies and research company providers

Focused ultrasound in neurosurgery: a historical perspective.

Focused ultrasound (FUS) has been under investigation for neurosurgical applications since the 1940s. Early experiments demonstrated ultrasound as an effective tool for the creation of intracranial lesions; however, they were limited by the need for craniotomy to avoid trajectory damage and wave distortion by the skull, and they also lacked effective techniques for monitoring. Since then, the development and hemispheric distribution of phased arrays has resolved the issue of the skull and allowed for a completely transcranial procedure. Similarly, advances in MR technology have allowed for the real-time guidance of FUS procedures using MR thermometry. MR-guided FUS (MRgFUS) has primarily been investigated for its thermal lesioning capabilities and was recently approved for use in essential tremor. In this capacity, the use of MRgFUS is being investigated for other ablative indications in functional neurosurgery and neurooncology. Other applications of MRgFUS that are under active investigation include opening of the blood-brain barrier to facilitate delivery of therapeutic agents, neuromodulation, and thrombolysis. These recent advances suggest a promising future for MRgFUS as a viable and noninvasive neurosurgical tool, with strong potential for yet-unrealized applications.

Multimodal MR imaging in hepatic encephalopathy: state of the art.

Hepatic encephalopathy (HE) is a neurological or neuropsychological complication due to liver failure or portosystemic shunting. The clinical manifestation is highly variable, which can exhibit mild cognitive or motor impairment initially, or gradually progress to a coma, even death, without treatment. Neuroimaging plays a critical role in uncovering the neural mechanism of HE. In particular, multimodality MR imaging is able to assess both structural and functional derangements of the brain with HE in focal or neural network perspectives. In recent years, there has been rapid development in novel MR technologies and applications to investigate the pathophysiological mechanism of HE. Therefore, it is necessary to update the latest MR findings regarding HE by use of multimodality MRI to refine and deepen our understanding of the neural traits in HE. Herein, this review highlights the latest MR imaging findings in HE to refresh our understanding of MRI application in HE.

MR技术在小流域山洪灾害防治中的应用研究

MR技术在小流域山洪灾害防治中的应用研究

Advantages of cortical surface reconstruction using submillimeter 7 T MEMPRAGE

Recent advances in MR technology have enabled increased spatial resolution for routine functional and anatomical imaging, which has created demand for software tools that are able to process these data. The availability of high-resolution data also raises the question of whether higher resolution leads to substantial gains in accuracy of quantitative morphometric neuroimaging procedures, in particular the cortical surface reconstruction and cortical thickness estimation. In this study we adapted the FreeSurfer cortical surface reconstruction pipeline to process structural data at native submillimeter resolution. We then quantified the differences in surface placement between meshes generated from (0.75 mm)3 isotropic resolution data acquired in 39 volunteers and the same data downsampled to the conventional 1 mm3 voxel size. We find that when processed at native resolution, cortex is estimated to be thinner in most areas, but thicker around the Cingulate and the Calcarine sulci as well as in the posterior bank of the Central sulcus. Thickness differences are driven by two kinds of effects. First, the gray–white surface is found closer to the white matter, especially in cortical areas with high myelin content, and thus low contrast, such as the Calcarine and the Central sulci, causing local increases in thickness estimates. Second, the gray–CSF surface is placed more interiorly, especially in the deep sulci, contributing to local decreases in thickness estimates. We suggest that both effects are due to reduced partial volume effects at higher spatial resolution. Submillimeter voxel sizes can therefore provide improved accuracy for measuring cortical thickness.