Magnetic Resonance Imaging Environment Research Articles

In vivo human knee varus-valgus loading apparatus for analysis of MRI-based intratissue strain and relaxometry

The diagnosis of early-stage osteoarthritis remains as an unmet challenge in medicine and a roadblock to evaluating the efficacy of disease-modifying treatments. Recent studies demonstrate that unique patterns of intratissue cartilage deformation under cyclic loading can serve as potential biomarkers to detect early disease pathogenesis. However, a workflow to obtain deformation, strain maps, and quantitative MRI metrics due to the loading of articular cartilage in vivo has not been fully developed. In this study, we characterize and demonstrate an apparatus that is capable of applying a varus-valgus load to the human knee in vivo within an MRI environment to enable the measurement of cartilage structure and mechanical function. The apparatus was first tested in a lab environment, then the functionality and utility of the apparatus were examined during varus loading in a clinical 3T MRI system for human imaging. We found that the device enables quantitative MRI metrics for biomechanics and relaxometry data acquisition during joint loading leading to compression of the medial knee compartment. Integration with spiral DENSE MRI during cyclic loading provided time-dependent displacement and strain maps within the tibiofemoral cartilage. The results from these procedures demonstrate that the performance of this loading apparatus meets the design criteria and enables a simple and practical workflow for future studies of clinical cohorts, and the identification and validation of imaging-based biomechanical biomarkers.

Denoising of the gradient artifact present in simultaneous studies of muscle blood oxygen level dependent (BOLD) signal and electromyography (EMG)

The MR-induced gradient artifact affects EMG recordings during simultaneous muscle BOLD/EMG acquisitions. However, no dedicated hardware can remove the gradient artifact easily, and alternative methods are expensive and time-consuming. This study aimed to develop three denoising methods requiring different processing levels and MR-compatible hardware.At two time points, surface EMG was recorded from the lower leg of 6 participants (50:50 sex ratio, age = 26.24.6 yrs., height = 173.59.2 cm, weight = 71.511.4 kg) using a plantar flexion-based block design consisting of 30s of rest followed by 30s of flexion for 5 min, under three conditions: inside the MRI bore, with and without a BOLD sequence (3 T, BOLD sequence, GRE EPI, 10 slices, 64×64 matrix, 2 mm thickness, and TE/TR/flip = 35/3000 ms/70), and outside the MRI environment. Simultaneous BOLD/EMG recordings were denoised using average artifact subtraction with three methods of artifact template creation, each having varying timing and hardware requirements. Method M1 builds the artifact template by recording the scanner triggers coming from the MRI; M2 creates the artifact template with a constant artifact period computed as TR/[number of slices]; M3 estimates the artifact template by looking at the periodicity of the gradient artifact located in the EMG recordings. Following postprocessing, SNR analysis was performed, comparing rest-to-flexion periods, to assess the efficacy of denoising methods and to compare differences between conditions.Linear mixed-effects models showed no significant differences in the mean SNR between denoising methods (p = 0.656). Furthermore, EMG SNR measurements were significantly affected by the magnetic environment (p < 0.05) but not by muscle fatigue over time (p = 0.975).EMG recordings contaminated with gradient artifacts during simultaneous BOLD/EMG can be efficiently denoised using all proposed methods, with two methods requiring no extra hardware. With minimal post-processing, EMG can easily be performed during muscle BOLD MRI studies.

Monolayer, open-mesh, pristine PEDOT:PSS-based conformal brain implants for fully MRI-compatible neural interfaces

Understanding brain function is essential for advancing our comprehension of human cognition, behavior, and neurological disorders. Magnetic resonance imaging (MRI) stands out as a powerful tool for exploring brain function, providing detailed insights into its structure and physiology. Combining MRI technology with electrophysiological recording system can enhance the comprehension of brain functionality through synergistic effects. However, the integration of neural implants with MRI technology presents challenges because of its strong electromagnetic (EM) energy during MRI scans. Therefore, MRI-compatible neural implants should facilitate detailed investigation of neural activities and brain functions in real-time in high resolution, without compromising patient safety and imaging quality. Here, we introduce the fully MRI-compatible monolayer open-mesh pristine PEDOT:PSS neural interface. This approach addresses the challenges encountered while using traditional metal-based electrodes in the MRI environment such as induced heat or imaging artifacts. PEDOT:PSS has a diamagnetic property with low electrical conductivity and negative magnetic susceptibility similar to human tissues. Furthermore, by adopting the optimized open-mesh structure, the induced currents generated by EM energy are significantly diminished, leading to optimized MRI compatibility. Through simulations and experiments, our PEDOT:PSS-based open-mesh electrodes showed improved performance in reducing heat generation and eliminating imaging artifacts in an MRI environment. The electrophysiological recording capability was also validated by measuring the local field potential (LFP) from the somatosensory cortex with an in vivo experiment. The development of neural implants with maximized MRI compatibility indicates the possibility of potential tools for future neural diagnostics.

MRI compatible electromagnetic actuator: magneto-thermal design and optimization

Purpose The purpose of this study is to develop a magnetic resonance imaging (MRI)-safe iron-free electrical actuator for MR-guided surgical interventions. Design/methodology/approach The paper deals with the design of an MRI compatible electrical actuator. Three-dimensional electromagnetic and thermal analytical models have been developed to design the actuator. These models have been validated through 3D finite element (FE) computations. The analytical models have been inserted in an optimization procedure that uses genetic algorithms to find the optimal parameters of the actuator. Findings The analytical models are very fast and precise compared to the FE models. The computation time is 0.1 s for the electromagnetic analytical model and 3 min for the FE one. The optimized actuator does not perturb imaging sequence even if supplied with a current 10 times higher than its rated one. Indeed, the actuator’s magnetic field generated in the imaging area does not exceed 1 ppm of the B0 field generated by the MRI scanner. The actuator can perform up to 25 biopsy cycles without any risk to the actuator or the patient since he maximum temperature rise of the actuator is about 20°C. The actuator is compact and lightweight compared to its pneumatic counterpart. Originality/value The MRI compatible actuator uses the B0 field generated by scanner as inductor. The design procedure uses magneto-thermal coupled models that can be adapted to the design of a variety actuation systems working in MRI environment.

Wearable Coaxially-Shielded Metamaterial for Magnetic Resonance Imaging.

Recent advancements in metamaterials have yielded the possibility of a wireless solution to improve signal-to-noise ratio (SNR) in magnetic resonance imaging (MRI). Unlike traditional closely packed local coil arrays with rigid designs and numerous components, these lightweight, cost-effective metamaterials eliminate the need for radio frequency cabling, baluns, adapters, and interfaces. However, their clinical adoption is limited by their low sensitivity, bulky physical footprint, and limited, specific use cases. Herein, a wearable metamaterial developed using commercially available coaxial cable, designed for a 3.0T MRI system is introduced. This metamaterial inherits the coaxially-shielded structure of its constituent cable, confining the electric field within and mitigating coupling to its surroundings. This ensures safer clinical adoption, lower signal loss, and resistance to frequency shifts. Weighing only 50g, the metamaterial maximizes its sensitivity by conforming to the anatomical region of interest. MRI images acquired using this metamaterial with various pulse sequences achieve an SNR comparable or even surpass that of a state-of-the-art 16-channel knee coil. This work introduces a novel paradigm for constructing metamaterials in the MRI environment, paving the way for the development of next-generation wireless MRI technology.

Novel MRI-compatible Zr–Mo–Nb alloys with superior mechanical performance, high corrosion resistance and good cytocompatibility for biomedical applications

Nowadays, MRI diagnostics have become indispensable in modern medicine, and the development of MRI-compatible materials is an urgent requirement for both modern medicine and materials science. Herein, MRI-compatible Zr–Mo–Nb alloys were developed by plasma arc melting and hot rolling process for biomedical applications. The Nb addition induces the composition segregation, β-Zr phase precipitations, and significant grain refinements in Zr–1Mo-xNb alloys, thereby contributing to an ultrafine α+β lamellar structure in hot-rolled (HRed) Zr–1Mo–3Nb alloys. Thanks to the nano-sized α+β lamellar structure, a high yield strength (YS) of 819.6 ± 20.9 MPa and an acceptable elongation of 11.8 ± 1% were realized in the HRed Zr–1Mo–3Nb alloy. Additionally, the incorporation of Nb with a high PB ratio and a relatively high equilibrium potential in the Zr–1Mo matrix enhances the stability of the passivation layer, leading to a more positive corrosion potential. Consequently, this significantly improves the corrosion resistance of HRed Zr–1Mo-xNb alloys. The Zr–1Mo–3Nb alloy exhibits lower magnetic susceptibility than the Zr–1Mo alloy, indicating improved MRI compatibility. Moreover, the HRed Zr–1Mo-xNb alloy shows excellent cytocompatibility to MC3T3-E1 cells, and good hemocompatibility of the experimental alloys were confirmed by the blood compatibility test. These findings highlight the potential of the MRI-compatible Zr–1Mo–3Nb alloy as a promising material for implants and devices in MRI environments, offering superior mechanical performance, high corrosion resistance and good biocompatibility.

A compact circuit-based metasurface for enhancing magnetic resonance imaging

Herein, we propose a compact 0.36 T MRI-enhancing circuit-based metasurface working at its third order mode. Different from most MRI-enhancing metasurface designs which exploit the fundamental mode with the highest enhancement, our choice is a trade-off between the enhancement and homogeneity. The metasurface is organized with capacitively-loaded metal wires where the capacitors decrease the electric length of the wires thus enabling a deep subwavelength scale. The working frequency of metasurface is tuned to the Larmor frequency, contributing to the redistribution of transmitted field. Full-wave simulations based on CST Microwave Studio compare the magnetic field in a mimicked MRI environment with and without the metasurface. The utilization of metasurface leads to a field enhancement ratio of 9.36-fold over a 28 × 28 cm2 area at 2 cm height while exceeding unity till almost 12 cm. Meanwhile, the variation of the quasi-homogenous magnetic field is less than 1/3 over a relatively large area. The impact of metasurface is further demonstrated by simulations with a head bio-model to evaluate the transmitted field strength and electromagnetic energy absorption. A preliminary measuring experiment is also conducted to validate the special mode pattern. The proposed metasurface effectively enhances the transmitted efficiency thus can be employed in clinical MRI to enhance imaging quality or reduce the input power. Moreover, this design paradigm is compatible with other enhancing approaches due to the nonmagnetic inclusions and frequency-dependent response and can be adapted for higher-field MRI systems by adjusting the length of metal wires and the value of loaded capacitors.

Safety of intracranial electrodes in an MRI environment: a technical report.

Intracranial electroencephalography (iEEG) involves placing intracranial electrodes to localise seizures in patients with medically refractory epilepsy. While magnetic resonance imaging (MRI) enables visualisation of electrodes within patient-specific anatomy, the safety of these electrodes must be confirmed prior to routine clinical utilisation. Therefore, the purpose of this study was to evaluate the safety of iEEG electrodes from a particular manufacturer in a 3.0-Tesla (3.0T) MRI environment. Measurements of magnetically induced displacement force and torque were determined for each of the 10 test articles using standardised techniques. Test articles were subsequently evaluated for radiofrequency-induced heating using a Perspex phantom in both open and 'fault' conditions. Additionally, we assessed radiofrequency (RF)-induced heating with all test articles placed into the phantom simultaneously to simulate an implantation, again in both open and 'fault' conditions. Finally, each test article was evaluated for MRI artefacts. The magnetically induced displacement force was found to be less than the force on the article due to gravity for all test articles. Similarly, the maximum magnetically induced torque was less than the worst-case torque due to gravity for all test articles apart from the 8-contact strip - for which it was 11% greater - and the depthalon cap. The maximum temperature change for any portion of any test article assessed individually was 1.7°C, or 1.2°C for any device component meant to be implanted intracranially. In the implantation configuration, the maximum recorded temperature change was 0.7°C. MRI may be safely performed for localising iEEG electrodes at 3.0T under certain conditions.

Magnetic resonance imaging respirators: a randomized crossover trial to assess respiratory protection, usability, and comfort.

Many available facepiece filtering respirators contain ferromagnetic components, which may cause significant problems in the magnetic resonance imaging (MRI) environment. We conducted a randomized crossover trial to assess the effectiveness, usability, and comfort of 3 types of respirators, judged to be "conditionally MRI safe" with an aluminum nosepiece (Halyard 46727 duckbill-type respirators and Care Essentials MSK-002 bifold cup-type respirators) or "MRI safe" completely metal free (Eagle AG2200 semirigid cup-type respirators). We recruited 120 participants to undergo a quantitative fit test (QNFT) on each of the 3 respirators in a randomized order. Participants then completed a usability and comfort assessment of each respirator. There were significant differences in the QNFT pass rates (51% for Halyard 46727, 73% for Care Essentials MSK-002, and 86% for Eagle AG2200, P < .001). The first-time fit test pass rate and overall fit factor were significantly higher for Eagle AG2200 compared with the other 2 respirators. Eagle AG2200 scored the lowest ratings in the ease of use and overall comfort. There were no significant differences in other modalities, including the seal rating, breathability, firmness, and overall assessment. Our study supports the utility of the Eagle AG2200 and Care Essentials MSK-002 respirators for healthcare professionals working in an MRI environment, based on their high QNFT pass rates and reasonably good overall usability and comfort scores. Eagle AG2200 is unique because of its metal-free construction. However, its comparatively lower usability and comfort ratings raise questions about practicality, which may be improved by greater user training.

CMR 2-41 - A Report of over 20 Consecutive Years of Imaging Pacemakers and Icds in the MRI Environment; The incremental Value of a Large, Prospective Observational Study

CMR 2-41 - A Report of over 20 Consecutive Years of Imaging Pacemakers and Icds in the MRI Environment; The incremental Value of a Large, Prospective Observational Study

Assessment of Exposure to Spatially Varying Magnetic Fields in MRI Environments: Modeling Analysis for Simulation Tools

Assessment of Exposure to Spatially Varying Magnetic Fields in MRI Environments: Modeling Analysis for Simulation Tools

Assessment of undergraduates nursing students’ knowledge toward MRI safety: Cross-sectional study

IntroductionMagnetic resonance imaging (MRI) has been traditionally regarded as a relatively safe imaging modality due to the absence of ionizing radiation. However, considerable immediate safety risks are intrinsic to the MRI environment, necessitating comprehensive awareness and training among healthcare professionals, particularly nurses, who accompany their patients to the MRI department in most cases. This study was carried out to evaluate the level of knowledge and awareness of MRI safety issues among nursing students within the nursing faculty at Jazan University (JU). Materials and methodsA descriptive, cross-sectional survey encompassing 128 undergraduate nursing students was conducted. A structured questionnaire comprising 25 questions was employed and classified into three sections, encompassing demographic data and MRI safety awareness. Data were analyzed using Microsoft Excel, and frequencies and percentages of responses were calculated and summarized. ResultsOf the 128 participants, 111 were females, and 17 were males, distributed across the 2nd (41%), 3rd (20%), and 4th (39%) academic years. Participants exhibited a commendable grasp of MRI contraindications related to ferromagnetic materials such as oxygen cylinders and metal needles. However, their knowledge concerning the operational aspects of MRI, such as examination duration, was found to be lacking, indicating a significant deficiency in comprehension regarding the operational aspects of MRI technology. ConclusionThis study highlights the relatively high level of awareness regarding MRI safety among nursing students at JU. However, the identified lack of knowledge pertaining to the operational aspects of MRI technology emphasizes the need for further education and training in this area. To address this gap, we recommend the establishment of comprehensive MRI safety courses and training programs customized for undergraduate nursing students.

Common Healthcare Related Instruments Subjected To Magnetic Attraction Study (CHRISTMAS): prospective in situ experimental study.

To investigate the behaviour of common healthcare related objects in a 3 tesla (T) MRI (magnetic resonance imaging) scanner, examining their ability to self-propel towards the scanner bore and their potential for tissue penetration. Prospective in situ experimental study. Clinical 3 T MRI scanner. Customised rig designed and built to guide objects towards the scanner bore. 12 categories of objects commonly found in hospitals, or on patients or healthcare professionals, or near an MRI scanning room. Human tissue penetration simulated with ballistic gel (Federal Bureau of Investigation and North Atlantic Treaty Organisation graded). SANTA (site where applied newtonian mechanics triggers acceleration) measurements and depth of tissue penetration of the objects. SANTA measurements ranged from 0 cm for the 20 pence, 50 pence, and £2 coins to 152-161 cm for a knife and the biscuit tins. One penny, two pence, five pence, and 10 pence coins showed self-propulsion and acceleration towards the scanner bore at a distance >100 cm from the gantry entry point. Linear regression analysis showed no apparent correlation between the weight of the objects and their SANTA measurements (R2<0.1). Only five objects penetrated the ballistic gel (simulated human tissue). The deepest penetration was by the knife (5.5 cm), closely followed by the teaspoon (5.0 cm), fork (4.0 cm), spoon (3.5 cm), and a 10 pence coin (0.5 cm). Although the biscuit tins did not penetrate the simulated human tissue, they exerted substantial impact force which could potentially cause bone fractures. A smartphone, digital thermometer, metallic credit card, and pen torch remained fully functional after several passes into the MRI scanner. No discernible loss of image quality for the MRI scanner after the experiments was found. The study highlights the potential for harm (major tissue damage and bone fractures) when commonly found objects in a healthcare setting are unintentionally brought into the MRI scanner room. Patients and healthcare professionals need to be aware of the dangers associated with bringing ferromagnetic objects into the MRI environment.

Effects of ultra-high field MRI environment on cognitive performance in healthy participants

IntroductionUltra-high field MRI (UHF MRI) is rapidly becoming an essential part of our toolbox within health care and research studies; therefore, we need to get a deeper understanding of the physiological effects of ultra-high field. This study aims to investigate the cognitive performance of healthy participants in a 7 T (T) MRI environment in connection with subjectively experienced effects. MethodsWe measured cognitive performance before and after a 1-h 7T MRI scanning session using a Digit Symbol Substitution Test (DSST) in 42 subjects. Furthermore, a computer-based survey regarding the subjectively experienced effects in connection with the MRI examination was distributed. Similarly, two DSSTs were also performed by a control group of 40 participants. ResultsEven though dizziness was the strongest sensory perception in connection to the MRI scanning, we did not find any correlation between dizziness and cognitive performance. Whilst the control group improved (p=<0.001) on their second DSST the MRI group showed no significant difference (p=0.741) in the DSST before and after MRI scanning. ConclusionTransient effect on cognition after undergoing MRI scanning can't be ruled out as the expected learning effect on the DSST was not observed. Implications for practiceIncreasing understanding of the possible adverse effects may guide operators in performing UHF MRI in a safe way and with person-centered care. Furthermore, it can guide researchers in setting up research protocols to minimize confounding factors in their fMRI studies due to the transient adverse effects of the UHF environment.

Provision of Safe Anesthesia in Magnetic Resonance Environments: Degree of Compliance with International Guidelines in Saudi Arabia.

The lack of local guidelines and regulations for the administration of anesthesia in magnetic resonance imaging (MRI) units presents a potential risk to patient safety in Saudi Arabia. Hence, this study aimed to evaluate the extent to which hospitals in Saudi Arabia follow international guidelines and recommendations for the safe and effective administration of anesthesia in an MRI environment. This study used a questionnaire that was distributed to 31 medical facilities in Saudi Arabia that provided anesthesia in MRI units. The findings of the study revealed that the mean compliance with the 17 guidelines across the 31 sites was 77%; 5 of the 31 sites (16.1%) had a compliance rate of less than 50% with the recommended guidelines. Only 19.4% of the institutes provided general safety education. Communication breakdowns between anesthesia providers and MRI teams were reported. To conclude, this survey highlights the status of anesthesia standards in Saudi Arabian MRI units and emphasizes areas that require better adherence to international guidelines. The results call for targeted interventions, including the formulation of specific national anesthesia guidelines for MRI settings. Communication breakdowns between anesthesia providers and MRI teams were reported at a rate of 83.9% during the administration of a gadolinium contrast agent. There were additional breakdowns, particularly for high-risk patients with implants, such as impaired respirators (74.2%), thus requiring further investigation due to potential safety incidents during MRI procedures. While considering the limitations of this study, such as potential biases and the low response rate, it provides a valuable foundation for refining protocols and promoting standardized practices in Saudi Arabian healthcare.

Evaluation of awareness and knowledge regarding MRI safety among students in the faculty of applied medical science at Jazan University

IntroductionMRI is a major advancement in the diagnostic imaging field. Due to the absence of ionizing radiation, MRI has traditionally been regarded as a safe imaging technique. Nonetheless, there exist environmental hazards that are associated with it, and it is imperative for healthcare practitioners to acknowledge and mitigate them. This study aimed to assess the knowledge of Faculty Applied Medical Science (FAMS) students at Jazan University toward MRI safety. MethodsThis was a descriptive cross-sectional study carried out at the FAMS. Data were collected through a questionnaire consisting of 15 yes-or-no questions. ResultsA total of 314 students (69.1% males, 30.9% females) responded to this cross-sectional survey. Around half of the sample (51%) were from diagnostic radiology department. Most students (83%) correctly identified MRI as a technique using a magnetic field but there were knowledge gaps regarding MRI-compatible devices. Despite the lack of prior experience, a significant proportion of students demonstrated knowledge regarding contraindications of metals and screening requirements. Significant differences were found based on age groups (<0.05), with variations in understanding MRI zones and the feasibility of pregnancy scans (<0.05). Gender differences were observed in knowledge about MRI scanning for patients with tattoos and prohibited items in the MRI room (p < .05). ConclusionThis study found that FAMS students demonstrated a significant level of awareness regarding potential hazards within the MRI environment. However, there was a notable knowledge gap regarding the functioning of the MRI device, as some students incorrectly believed it utilized ionizing radiation and could be deactivated after procedures. These findings highlight the importance of enhancing education and training on MRI safety, including accurate knowledge about MRI technology and its potential risks. By addressing these knowledge gaps, future healthcare professionals can contribute to ensuring the safety of patients and staff during MRI procedures.

Challenges in Acquiring Clinical Simultaneous SPECT-MRI on a PET-MRI Scanner

The INSERT is the world’s first clinical SPECTMRI brain imaging system based on scintillation detectors with a SiPM readout. Here we demonstrate its use within a clinical MRI environment for the first time. Using a standard transmit-receive head coil, and with an appropriate selection of a custom MRI sequence (GRE), we overcome mutual interference. The INSERT and its bulky 50 kg tungsten collimator introduce magnetic field inhomogeneity. Due to the specific MRI-compatible collimator design, inhomogeneity is compensated by shimming, leading to simultaneous acquisition. We process the SPECT data acquired alongside the MRI sequence to evaluate the SPECT system performance and the impact of the MRI. Finally, we present a set of simultaneous SPECT-MRI acquisitions, demonstrating multimodal imaging capabilities, albeit with a limited MRI sequence.

7T Magnetic Compatible Multimodality Electrophysiological Signal Recording System

This paper developed a comprehensive magnetic resonance imaging (MRI)-compatible electrophysiological (EP) acquisition system, which can acquire various physiological electrical signals, including electrocardiography (ECG), electromyography (EMG), electroencephalography (EEG) and electrocorticogram (ECoG), and EP recording combined with multimodal stimulation. The system is designed to be compatible with the 7-Tesla (7T) ultra-high field MRI environment, providing convenience for neuroscience and physiological research. To achieve MRI compatibility, the device uses magnetically compatible materials and shielding measures on the hardware and algorithm processing on the software side. Different filtering algorithms are adopted for different signals to suppress all kinds of interference in the MRI environment. The system can allow input signals up to ±0.225 V and channels up to 256. The equipment has been tested and proven to be able to collect a variety of physiological electrical signals effectively. When scanned under the condition of a 7T high-intensity magnetic field, the system does not generate obvious heating and can meet the safety requirements of MRI and EEG acquisition requirements. Moreover, an algorithm is designed and improved to efficiently and automatically remove the gradient artifact (GA) noise generated by MRI, which is a thousand-fold gradient artifact. Overall, this work proposes a complete, portable, MRI-compatible system that can collect a variety of physiological electrical signals and integrate more efficient GA removal algorithms.

Non-invasive estimation of arterial blood pressure fluctuations using a peripheral photoplethysmograph inside the MRI scanner.

The blood-oxygen-level-dependent (BOLD) signal measured by functional magnetic resonance imaging (fMRI) is modulated by neural activity through the neurovascular coupling effect, as well as non-neural factors of physiological origin such as heart rate, respiration, and arterial blood pressure (ABP). While the former two effects have been previously characterized, the modulation of the BOLD signal by ABP fluctuations is still poorly understood. This is largely due to the difficulty of obtaining reliable ABP measurements in the MRI environment. Here, we propose a combined experimental and mathematical modeling framework to estimate ABP fluctuations inside the MRI scanner using photoplethysmography (PPG). Specifically, we used concurrent PPG and ABP measurements obtained outside the scanner to train the mathematical model and applied it to PPG measurements obtained inside the MRI scanner. Our results suggest good agreement between the model-predicted and experimentally measured ABP fluctuations and region specific correlations with the BOLD fluctuations.

Advanced software for MRgFUS treatment planning

Background and objectivesHerein, a user-friendly software platform for 3-dimensional Focused Ultrasound treatment planning based on Magnetic Resonance Imaging (MRI) images is presented. MethodsThe software directly retrieves and loads MRI images. Various design tools can be used on the MRI images to define the treatment area and the sonication parameters. Based on the treatment plan, the software controls the robotic motion and motion pattern of Magnetic Resonance guided Focused Ultrasound (MRgFUS) robotic systems to execute the treatment procedure. Real-time treatment monitoring is achieved through MRI images and thermometry. The software's functionality and performance were evaluated in both laboratory and MRI environments. Different treatment plans were designed on MRI images and sonications were executed on agar-based phantoms and polymer films. ResultsMagnetic Resonance (MR) thermometry maps were acquired in the agar-based phantoms. An exceptional agreement was observed between the software-planned treatment area and the lesions produced on the polymer films. ConclusionsThe developed software was successfully integrated with the MRI and robotic system controls for performing accurate treatment planning and real-time monitoring during sonications. The software provides an extremely user-friendly interface, while in the future it could be enhanced by providing dynamic modulation of the ultrasonic parameters during the treatment process.