Anatomical Human Model Research Articles

Establishing the Biofidelity of a Multiphysics Finite Element Model of the Human Heart.

Accelerating development of new therapeutic cardiac devices remains a clinical and technical priority. High-performance computing and the emergence of functional and complex in silico models of human anatomy can be an engine to accelerate the commercialization of innovative, safe, and effective devices. An existing three-dimensional, nonlinear model of a human heart with flow boundary conditions was evaluated. Its muscular tissues were exercised using electrophysiological boundary conditions, creating a dynamic, electro-mechanical simulation of the kinetics of the human heart. Anatomic metrics were selected to characterize the functional biofidelity of the model based on their significance to the design of cardiac devices. The model output was queried through the cardiac cycle and compared to in vivo literature values. For the kinematics of mitral and aortic valves and curvature of coronary vessels, the model's performance was at or above the 95th percentile range of the in vivo data from large patient cohorts. One exception was the kinematics of the tricuspid valve. The model's mechanical use environment would subject devices to generally conservative use conditions. This conservative simulated use environment for heart-based medical devices, and its judicious application in the evaluation of medical devices is justified, but careful interpretation of the results is encouraged.

A papier-maché human anatomical model used in the Madras Medical Establishment in the 1830s

An untitled 2-page notice by a Madras Civil Servant John Morris sleeved under ‘Scientific Intelligence’ in the inaugural issue of the Madras Journal of Literature & Science (1834) refers to a human anatomical model built by Louis Aujoux, a French physician–anatomist–model maker. Highly likely this model was used at the Madras Medical Establishment to teach basic medicine to trainees of the Subordinate Medical Service. This was brought to Madras by Surgeon George Knox of the Madras Medical Establishment in the early 1830s, before the establishment of the Madras Medical School under the superintendence of William Mortimer. A similar model was acquired by the Calcutta Medical Establishment a little earlier. The present article, keeping the human anatomical model as the central element, refers to the development of interest in designing human models for purposes of teaching medicine in Europe. That interest stimulated using such models in India as well. The present article also refers to the medical interests of the scholar–princes of Tanjavur and Travancore of the nineteenth century India, who maintained models of full human skeletons, not of bones but made of ivory, in their Curiosity Cabinets (Kunstkammern). From the 2-page notice of Morris, we understand that the model that came to Madras from France was a gift to the Government of Madras for teaching purposes. No further details are traceable.

Fascia and tensegrity: The quintessence of a unified systems conception

The heterogeneous connective tissue fascia is constructed upon a tensegrity-based architecture providing cells and organism’s with stability coupled with mobility. A term coined by Sharkey and Avison “Fasciategrity” used for the first time at the British Fascia Symposium 2018, speaks of the relationship of balance and integrity within the fascial net. Tensegrity construction principles provide an opportunity to deliver, to medical trainees and post-graduate medical specialists, a unified systems conception of living form and function. In this the 21st century anatomists are ready to move away from a mechanical view of the human corpus based on a 17th century model of parts and levers. A new emphasis is required to integrate current models and theories that substantiate fascia as the connected, unifying, continuous universal singularity that permeates the entire soma. Such models and theories are complex, however, with increased crosstalk between experts and professionals in fields of specialty, within scientific disciplines, a new paradigm is emerging. This new unified systems approach to human anatomy and physiology has the potential to impact global healthcare. A unified systems model of human anatomy (with a special focus on the architecture of fascia) is one that is predicated upon a specific ‘nature inspired’ tensegrity architecture utilizing soft matter as the building material during embryonic self-construction. Self-construction leads to emerging transformations that are driven by both genetic and epigenetic stresses [i.e., biochemical and biophysical cues] embracing collective behaviour with emerging small world networks that utilize non-linear dynamics. Time is a key component as self-organization occurs in a hierarchical time-dependent/temporal sequalae. This short paper focuses on the essential architectural characteristics of cells and multi-cellular organisms that supports a living unified system. While the human body is a true reflection of infinity and continuity it also possesses virtual boarders, boundaries and compartmentalization’s. Such virtual borders and boundaries are self-constructed connections, disconnections and compartments necessary for physiology, metabolism and autoimmune responses reflecting evolutionary contingency. KEY WORDS: Fascia, Tensegrity, Continuity, Unified Systems, Biotensegrity, Stability, Embryology.

Path Loss Analysis and Transceiver Development for Human Body Communication-Based Signal Transmission for Wearable Robot Control

Human body communication (HBC) technology is attracting a lot of attention for monitoring vital data and controlling wearable robot. In this paper, we focused on electroencephalogram (EEG) signal transmission from head to wrist in the 10–60 MHz HBC band. This is based on an idea to transmit an EEG signal to control a wearable robot. First, we clarified the basic transmission mechanism and characteristics using a highly simplified human body model. Next, we performed a detailed path loss analysis by finite difference time domain simulation using an anatomical human body model with various postures. Based on the analysis results, we identified the optimum transmitter position on the head and developed an impulse radio transceiver for verifying the feasibility of the technique. The results show that the developed transceiver can provide a data rate of 10 Mbps and the bit error rate can be kept below 10−3 for transmitting the EEG signals from the head to the wrist. Experimental validation with a bio-equivalent gel phantom also demonstrated high feasibility of transmitting the EEG signals along the human arm.

Body Core Temperature Estimation Using New Compartment Model With Vital Data From Wearable Devices

With increasing heat-wave frequency, the prevention and public awareness of heat-related illnesses has become an essential topic. In the standard for heat strain and stress, empirical guidelines to prevent excess core temperature rise above 1 °C have been prescribed for workers. However, measuring core temperature change in our daily life or working place is not straightforward. The estimation of core temperature from measured vital signals in a non-invasive manner is thus essential for the management of heat stress or strain. Here, we propose an estimation method for core temperature change by a simplified thermodynamics model with the measured heart rate and ambient conditions (temperature and relative humidity). Our proposed model is based on a two-layer two-compartment model with tuned parameters, which were derived from comparison between the computations using high-resolution anatomical human body model. Our model exhibited good agreement with the measured core temperature rise; the computed and measured core temperature rise for the naked trial were 0.54 °C and 0.53 °C, whereas those for the clothed trial were 0.70 °C, and 0.71 °C, respectively. Furthermore, our compartment model with vital data measured from a wearable device achieved good estimation in real time for field measurement in addition to computational replication with a previous study.

Modeling Electromagnetic Exposure in Humans Inside a Whole-Body Birdcage Coil Excited by a Two-Channel Parallel Transmitter Operated at 123 MHz

The influence of the accuracy level for whole-body birdcage coil models on electromagnetic exposure estimations was evaluated using three anatomical human body models located at the head landmark position. Both generic and vendor-specific birdcage coil models were created and analyzed using a radio-frequency (RF) circuit and a three-dimensional electromagnetic (EM) co-simulation approach to evaluate EM properties of the coil used in a commercial 3T magnetic resonance imaging (MRI) scanner. The fidelity of the coil geometry and excitation, as well as consideration of permissible variations of the coil electrical components and capacitor losses, had a significant impact on the estimated electric field distributions inside the human models. Therefore, the variety of electric fields generated in humans should be carefully considered for a reliable RF safety assessment of a patient with a passive or active implant undergoing a scan in a modern MRI scanner with dual-channel transmit RF coils.

Simulator-generated training datasets as an alternative to using patient data for machine learning: An example in myocardial segmentation with MRI

Background and Objective: Supervised Machine Learning techniques have shown significant potential in medical image analysis. However, the training data that need to be collected for these techniques in the field of MRI 1) may not be available, 2) may be available but the size is small, 3) may be available but not representative and 4) may be available but with weak labels. The aim of this study was to overcome these limitations through advanced MR simulations on a realistic computer model of human anatomy without using a real MRI scanner, without scanning patients and without having personnel and the associated expenses.Methods: The 4D-XCAT model was used with the coreMRI simulation platform for generating artificial short-axis MR-images for training a neural-network to automatic delineate the LV endocardium and epicardium. Its performance was assessed on real MR-images acquired from eight healthy volunteers. The neural-network was also trained on real MR-images from a publicly available dataset and its performance was assessed on the same volunteers’ data.Results: The proposed solution demonstrated a performance of 94% (endocardium) and 90% DICE (epicardium) in real mid-ventricular slices, whereas a 10% addition of real MR-images in the artificial training dataset increased the performance to 97% DICE. The use of artificial MR-images that cover the entire LV yielded 85% (endocardium) and 88% DICE (epicardium) when combined with real MR data with an 80%-20% mix respectively.Conclusions: This study suggests a low-cost solution for constructing artificial training datasets for supervised learning techniques in the field of MR by using advanced MR simulations without the use of a real MRI scanner, without scanning patients and without having to use specialized personnel, such as technologists and radiologists.

Effects of patient orientations, landmark positions, and device positions on the MRI RF-induced heating for modular external fixation devices.

This paper studies the RF-induced heating for modular external fixation devices applied on the leg regions of the human bodies. Through numerical investigations of RF-induced heating related to different patient orientations, landmark positions, and device positions under 1.5T and 3T MRI systems, simple and practical methods to reduce RF-induced heating are recommended. Numerical simulations using a full-wave electromagnetic solver based on the finite-difference time-domain method were performed to characterize the effects of patient orientations (head-first/feet-first), landmark positions (the scanning area of the patient), and device positions (device on left or right leg) on the RF-induced heating of the external fixation devices. The G32 coil design and three anatomical human models (Duke model, Ella model, and Fats model) were adopted to model the MRI RF coil and the patients. The relative positions of the patient, device, and coil can significantly affect the RF-induced heating. With other conditions remaining the same, changing the device position or patient orientation can lead to a peak 1-g averaged spatial absorption ratio variation of a factor around four. By changing the landmark position and the patient orientation, the RF-induced heating can be reduced from 1323.6 W/kg to 217.5 W/kg for the specific scanning situations studied. Patient orientations, landmark positions, and device positions influence the RF-induced heating of modular external fixation devices at 1.5 T and 3 T. These features can be used to reduce the RF-induced heating during MRI simply and practically.

Biomechanical analysis of peri‑implant fractures in short versus long cephalomedullary implants following pertrochanteric fracture consolidation

IntroductionPertrochanteric femur fracture fixation with use of cephalomedullary nails (CMN) has become increasingly popular in recent past. Known complications after fracture consolidation include peri‑implant fractures following the use of both short and long nails, with fracture lines around the tip of the nail or through the interlocking screw holes, resulting in secondary midshaft or supracondylar femur fractures, respectively. Limited research exists to help the surgeon decide on the use of short versus long nails, while both have their benefits. The aim of this biomechanical study is to investigate in direct comparison one of the newest generations short and long CMNs in a human anatomical model, in terms of construct stability and generation of secondary fracture pattern following pertrochanteric fracture consolidation. MethodsEight intact human anatomical femur pairs were assigned to two groups of eight specimens each for nailing using short or long CMNs. Each specimen was first biomechanically preloaded at 1 Hz over 2000 cycles in superimposed synchronous axial compression to 1800 N and internal rotation to 11.5 Nm. Following, internal rotation to failure was applied over an arc of 90° within one second under 700 N axial load. Torsional stiffness as well as torque at failure, angle at failure, and energy to failure were evaluated. Fracture patterns were analyzed. ResultsOutcomes in the study groups with short and long nails were 9.7 ± 2.4 Nm/° and 10.2 ± 2.9 Nm/° for torsional stiffness, 119.8 ± 37.2 Nm and 128±46.7 Nm for torque at failure, 13.5 ± 3.5° and 13.4 ± 2.6° for angle at failure, and 887.5 ± 416.9 Nm° and 928.3 ± 461.0 Nm° for energy to failure, respectively, with no significant differences between them, p ≥ 0.17. Fractures through the distal locking screw holes occurred in 5 and 6 femora instrumented with short and long nails, respectively. Fractures through the lateral entry site of the head element were detected in 3 specimens within each group. For short nails, fractures through the distal shaft region, not interfacing with the implant, were detected in 3 specimens. ConclusionFrom a biomechanical perspective, the risk of secondary peri‑implant fracture after intramedullary fixation of pertrochanteric fractures is similar when using short or long CMN. Moreover, for both nail versions the fracture pattern does not unexceptionally involve the distal locking screw hole.

Miniaturized Dual-Resonant Helix/Spiral Antenna System at MHz-Band for FSK Impulse Radio Intrabody Communications

In this article, a miniaturized dual-resonant antenna system at MHz-band operating at around 20 and 50 MHz is proposed for frequency-shift keying impulse radio (FSK-IR) intrabody communications. This antenna system comprises a swallowable helix-coil in-body antenna with a hollow cylindrical shape of 10 mm diameter and 30 mm length, and two single band on-body matched planar spiral-coil antennas with a compact size of 79 mm $\times\,\,72$ mm $\times\,\,2.8$ mm. For in-body antenna design, a nonuniform helical pitch structure is utilized to produce dual-resonant frequencies. The soft ferrite magnetic sheet with high relative permeability and low dissipation factor is used as a flexible conformal substrate to realize antenna miniaturization without lumped element loading. Simulation results for antenna performance, electromagnetic field distribution, and specific absorption rate are presented with different tissue-type phantoms, as well as an anatomical numerical human model. In addition, experimental verification of antenna performance and implant transmission characteristics is also conducted in a liquid phantom. At an implant depth of 50 mm, the measured maximum transmission coefficients are −33 and −45 dB at the dual-resonant frequency bands, respectively. Simulation and measurement results demonstrate that the proposed dual-resonant antenna is suitable for the FSK-IR system and can be expected to realize a data rate as high as 10 Mb/s for biomedical implant applications at MHz-band.

Double Split Rings as Extremely Small and Tuneable Antennas for Brain Implantable Wireless Medical Microsystems

Wireless intracranial implantable microsystems are believed to potentially innovate the management of brain disorders and the treatment of neurological diseases. The fundamental challenge in the development of the wireless implantable system is the attainment of miniature antennas achieving adequately high efficiency for signaling and wireless power transfer in the presence of the dissipative intracranial tissues. Here, we demonstrate and evaluate an effective approach that utilizes the coupled split rings to develop the miniature implantable antenna. With the proposed approach, the antenna size can be decreased to π × (3 × 1.5) × 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> which is less than 2% of the operating wavelength at 915 MHz, while the antenna maintains the gain of -25 dBi when placed 16 mm deep in the anatomical human head model. As a proof of concept, we developed RFID tags based on the proposed antenna and verified their performance with tissue mimicking liquid and in vivo experiment with rats. The measured maximum read range of the tags reaches 0.7 and 1.1 m when immersed 30 mm in the tissue mimicking liquid and implanted 6 mm in a rat's cranial cavity, respectively.

NCINM: organ dose calculator for patients undergoing nuclear medicine procedures

Nuclear medicine is the second largest source of medical radiation exposure to the general population after computed tomography imaging. Informed decisions regarding the use of nuclear medicine procedures require a better understanding of the magnitude of radiation dose and associated health risks. However, existing model-based organ dose estimation tools rely on simplified human anatomy models or commercial programs. Therefore, we developed a publicly-available dose calculation tool based on more sophisticated human anatomy models. We calculated a comprehensive library of photon and electron specific absorbed fractions (SAF) for multiple combinations of source and target regions within a series of pediatric and adult computational human phantoms matching the International Commission on Radiological Protection (ICRP)’s reference data, combined with a Monte Carlo radiation transport code. Then, we derived a library of S values from these SAFs and the nuclear decay data from ICRP Publication 107. Finally, we created a graphical user interface, named National Cancer Institute Dosimetry System for Nuclear Medicine (NCINM), to facilitate the dosimetry process. Approximately 13 million S values were derived from 2 million SAFs computed in this work. Comprehensive comparisons were conducted at different steps of the dosimetry chain with data available in software OLINDA/EXM 1.0 and IDAC 2.1. For instance, median ratios of photon self-absorption SAFs available from OLINDA/EXM 1.0 and IDAC 2.1 to those calculated in this study were 1.3 (interquartile range = 1.1–1.6) and 1.0 (interquartile range = 0.98–1.0), respectively. SAF differences between NCINM and OLINDA/EXM 1.0 were explained by the large inter-phantom anatomical variability. Our results illustrate the importance of realistic human anatomy models for use in dosimetry software. More phantoms and radionuclides, as well as a biokinetic module, will soon be added. Applications of the NCINM program include computation of absorbed doses for use in radiation epidemiologic studies and patient dose monitoring in nuclear medicine.

Numerical modeling and assessment of human exposure to radiofrequency electromagnetic fields used for wireless communication system installed on a smart meter

AbstractWe assessed human exposure to radiofrequency (RF) electromagnetic fields used for a wireless communication system installed on a smart meter for communication in the 920 MHz band. In an exposure guideline, the specific absorption rate (SAR) is used as a measure of the thermal effects of human exposure to electromagnetic fields. Although the low‐power wireless communication device used for the smart meter inherently complies with the exposure guideline, the assessment of the RF electromagnetic field exposure is useful to deepen our understanding of human safety. For the exposure assessment, first, a computational smart meter model was constructed and validated by comparison with the measured data of electric fields around an actual smart meter. Using the computational smart meter model, we calculated the SAR in the head of an anatomical human model that was located very close to the smart meter. The maximum SAR in the head was obtained when the antenna was placed in front of a human eye, which was calculated to be 10.3 mW/kg for an input power of 20 mW. It was shown that the maximum SAR was 200 times smaller than the basic restriction level in the exposure guideline.

INFLUENCE OF VIRTUAL REALITY TOOLS ON HUMAN ANATOMY LEARNING

The paper considers virtual reality (VR) as an effective way of teaching and learning. It discusses the possibilities of modern educational information technologies implementation, the educational advantages and drawbacks of 3D technologies and highlights VR features which enable dynamic forms of learning by creating artifacts in virtual environment with activities triggered by learners’ interaction. The effective role of the means of VR in education is determined and theoretically substantiated. Approaches aimed at increasing the theoretical and practical readiness of learners for educational activity using VR tools are considered.&#x0D; The research participants were exposed to two learning modes: traditional (textbook style) and VR. The experiment was based on Human Anatomy VR Complete Edition by Virtual Medicine software which provided interaction with virtual models of human anatomy. Anatomy knowledge test and Students' Engagement in School Four-dimensional Scale were used to compare learning outcomes and the levels of student cognitive engagement between the two groups on the basis of ANOVA test.&#x0D; Participants in the VR mode improved learning performance (i.e. recollecting and reconstituting) and engagement scores (cognitive and agency subscales) compared to those in the traditional learning mode. Emotional self-ratings before and after the learning phase in the VR mode showed an increase in positive emotions and a decrease in negative emotions. Overall, participants in the VR mode displayed an improved learning experience when compared to traditional learning methods. The combination of visualization and interactivity makes VR learning mode advantageous for effective education. The directions of further research such as organizational and psycho-pedagogical conditions of VR implementation in education and teacher training are defined.

Eyes in Ears: A Miniature Steerable Digital Endoscope for Trans-Nasal Diagnosis of Middle Ear Disease.

The aim of this work is to design, fabricate and experimentally validate a miniature steerable digital endoscope that can provide comprehensive, high-resolution imaging of the middle ear using a trans-nasal approach. The motivation for this work comes from the high incidence of middle ear diseases, and the current reliance on invasive surgery to diagnose and survey these diseases which typically consists of the eardrum being lifted surgically to directly visualize the middle ear using a trans-canal approach. To enable less-invasive diagnosis and surveillance of middle ear disease, we propose an endoscope that is small enough to pass into the middle ear through the Eustachian tube, with a steerable tip that carries a 1 Megapixel image sensor and fiber-optic illumination to provide high-resolution visualization of critical middle ear structures. The proposed endoscope would enable physicians to diagnose middle ear disease using a non-surgical trans-nasal approach instead, enabling such procedures to be performed in an office setting and greatly reducing invasiveness for the patient. In this work, the computational design of the steerable tip based on computed tomography models of real human middle ear anatomy is presented, and these results informed the fabrication of a clinical-scale steerable endoscope prototype. The prototype was used in a pilot study in three cadaveric temporal bone specimens, where high-quality middle ear visualization was achieved as determined by an unbiased cohort of otolaryngologists. This is the first paper to demonstrate cadaveric validation of a digital, steerable, clinical-scale endoscope for middle ear disease diagnosis, and the experimental results illustrate that the endoscope enables the visualization of critical middle ear structures (such as the epitympanum or sinus tympani) that were seldom or never visualized in prior published trans-Eustachian tube endoscopy feasibility studies.

SPARC: Development of Human and Rodent Neuro‐Functionalized Computational Anatomical Models with Detailed Mapping of Peripheral Nervous System

There is a growing trend within the neuroscience community and the medical and health industries towards bioelectronics medicine: applying electrical signals to the nervous system to control and modulate functions of the body. These so‐called “electroceuticals” include numerous types of neurostimulation devices. To this end, we have developed reference animal and human anatomical models with unprecedented details in the peripheral nervous system, and connectivity to organs and muscles, which were functionalized with compartmental neuronal dynamics models to investigate device interactions with neuronal electrophysiology. The whole body rat model is being segmented from co‐registered high‐resolution (80 × 80 × 80 μm) magnetic resonance imaging (MRI) and computed tomography (CT) images of a female rat. The Visible Korean Human (1) male and female cryosection data was used as the basis for the new human phantoms, due to the unique resolution (0.1 × 0.1 × 0.2 mm) and quality of these images. To model important peripheral nerves trajectories, the nerves were segmented and anatomically correct trajectories were extracted automatically using a set of anatomical rules specifying, which dorsal or ventral roots are connected to a given nerve. Functionalization is achieved by assigning electrophysiological models of myelinated and unmyelinated axons to axon trajectories within nerve models based on histological investigations documented in the literature (2).The new human female and male human models called Yoon‐sun and Jeduk respectively, have been released as part of the Virtual Population (3) V4.0 model library. The neuro‐functionalized rat will be completed soon. These models will become integration centers for NIH SPARC neuroanatomy and electrophysiology models (4) and are expected to significantly influence the field of computational neuro‐electrophysiology research enabling studies of multi‐scale models with realistic anatomies and electrophysiology. Simulations will enhance our understanding of mechanisms of neurostimulation, e.g., by MRI gradient fields, provide experimental test‐beds for new therapeutic approaches and devices, and enable study of safety aspects, thus providing a tool to facilitate regulatory submissions and standardization activities.Support or Funding InformationThis work has been done with funding from NIH SPARC (1OT3OD025348‐01S1). The work on human anatomical models also received funding from Innosuisse (25290.1 PFLS‐LS) and KIAT.Computational rat model is shown with muscle tissue and limbs clipped to show interior tissue structures.Figure 1Side‐by‐side visualization of different tissue structures in the female computational human anatomical model ‘Yoon‐sun’. The model contains approximately 1100 separate tissues, with detailed bones, organs, muscles, blood vessels and peripheral nervous system (right).Figure 2

COMPLIANCE TESTING FOR HUMAN BODY MODEL EXPOSURE TO ELECTROMAGNETIC FIELDS FROM A HIGH-POWER WIRELESS CHARGING SYSTEM FOR DRONES.

Recently, a wireless charging system (WCS) for drones has been extensively studied, although standards for compliance testing of a WCS for drones have yet to be established. In this study, we propose methods for human exposure assessments of a WCS for drones by comprehensively considering the various positions of the system and the postures of human body models. The electromagnetic fields from a WCS are modeled and the internal quantities of the human body models, consisting of current density, internal electric field and specific absorption rate, are calculated. The incident fields around the WCS and the internal quantities are analyzed at 140kHz, which is the operating frequency of the WCS applied. Results of an exposure assessment based on the confirmed worst-case scenario are presented. In addition, the internal quantities depending on the human body models and the material characteristics of the simplified models are also discussed using four different anatomical and simplified human body models.

Predicting in vivo MRI Gradient-Field Induced Voltage Levels on Implanted Deep Brain Stimulation Systems Using Neural Networks.

IntroductionMRI gradient-fields may induce extrinsic voltage between electrodes and conductive neurostimulator enclosure of implanted deep brain stimulation (DBS) systems, and may cause unintended stimulation and/or malfunction. Electromagnetic (EM) simulations using detailed anatomical human models, therapy implant trajectories, and gradient coil models can be used to calculate clinically relevant induced voltage levels. Incorporating additional anatomical human models into the EM simulation library can help to achieve more clinically relevant and accurate induced voltage levels, however, adding new anatomical human models and developing implant trajectories is time-consuming, expensive and not always feasible.MethodsMRI gradient-field induced voltage levels are simulated in six adult human anatomical models, along clinically relevant DBS implant trajectories to generate the dataset. Predictive artificial neural network (ANN) regression models are trained on the simulated dataset. Leave-one-out cross validation is performed to assess the performance of ANN regressors and quantify model prediction errors.ResultsMore than 180,000 unique gradient-induced voltage levels are simulated. ANN algorithm with two fully connected layers is selected due to its superior generalizability compared to support vector machine and tree-based algorithms in this particular application. The ANN regression model is capable of producing thousands of gradient-induced voltage predictions in less than a second with mean-squared-error less than 200 mV.ConclusionWe have integrated machine learning (ML) with computational modeling and simulations and developed an accurate predictive model to determine MRI gradient-field induced voltage levels on implanted DBS systems.

Accuracy Assessment of Numerical Dosimetry for the Evaluation of Human Exposure to Electric Vehicle Inductive Charging Systems

In this article, we discuss numerical aspects related to the accuracy and the computational efficiency of numerical dosimetric simulations, performed in the context of human exposure to static inductive charging systems of electric vehicles. Two alternative numerical methods based on electric vector potential and electric scalar potential formulations, respectively, are here considered for the electric field computation in highly detailed anatomical human models. The results obtained by the numerical implementation of both approaches are discussed in terms of compliance assessment with ICNIRP guidelines limits for human exposure to electromagnetic fields. In particular, different strategies for smoothing localized unphysical outliers are compared, including novel techniques based on statistical considerations. The outlier removal is particularly relevant when comparison with basic restrictions is required to define the safety of electromagnetic fields exposure. The analysis demonstrates that it is not possible to derive general conclusions about the most robust method for dosimetric solutions. Nevertheless, the combined use of both formulations, together with the use of an algorithm for outliers removal based on a statistical approach, allows to determine final results to be compared with reference limits with a significant level of reliability.

Anterior component separation, external retrofascial approach: Is that an option?

BACKGROUND AND AIMS: The eventration involves a highly variable surgical entity with a wide range of possible surgical techniques for its repair, without having found a “Gold Standard” technique. With these animal study, we propose a possible and useful surgical procedure for hernia repair. MATERIALS AND METHODS: We present a modified technique of the anterior component separation (ACS) based on a release of the external oblique muscle from a posterior anatomical approach, accessing the space from the retrofascial space of the anterior sheath of the rectus abdominis muscle. The technique was performed in an experimental animal model with pigs of the “Large White” breed of 20-25 kg since the pig is a good representative model of human anatomy and its abdominal wall. RESULTS: The technique was performed in an experimental animal model with pigs of the “Large White” breed. The procedure through the anterior retrofascial space of the rectus abdominal muscle was easily done, allowing the access to the inter-oblique space and facilitating the release of the external oblique muscle. CONCLUSION: Waiting for its clinical application, the ACS by its external retrofascial space approach could be an interesting surgical resource for incisional hernia repair.