Visible Human Project® female surface based computational phantom (Nelly) for radio-frequency safety evaluation in MRI coils

Quantitative modeling of specific absorption rate and temperature rise within the human body during 1.5 T and 3 T MRI scans is of clinical significance to ensure patient safety. This work presents justification, via validation and comparison, of the potential use of the Visible Human Project (VHP) derived Computer Aided Design (CAD) female full body computational human model for non-clinical assessment of female patients of age 50–65 years with a BMI of 30–36 during 1.5 T and 3 T based MRI procedures. The initial segmentation validation and four different application examples have been identified and used to compare to numerical simulation results obtained using VHP Female computational human model under the same or similar conditions. The first application example provides a simulation-to-simulation validation while the latter three application examples compare with measured experimental data. Given the same or similar coil settings, the computational human model generates meaningful results for SAR, B1 field, and temperature rise when used in conjunction with the 1.5 T birdcage MRI coils or at higher frequencies corresponding to 3 T MRI. Notably, the deviation in temperature rise from experiment did not exceed 2.75° C for three different heating scenarios considered in the study with relative deviations of 10%, 25%, and 20%. This study provides a reasonably systematic validation and comparison of the VHP-Female CAD v.3.0–5.0 surface-based computational human model starting with the segmentation validation and following four different application examples.

Digital Feast and Physical Famine: The Altered Ecosystem of Anatomy Education due to the Covid-19 Pandemic

This article explores the effects of the coronavirus disease 2019 (Covid-19) pandemic on the evolution of both physical and digital cadavers within the unique ecosystem of the anatomy laboratory. A physical cadaver is a traditional and established learning tool in anatomy education, whereas a digital cadaver is a relatively recent phenomenon. The Covid-19 pandemic presented a major disturbance and disruption to all levels and types of education, including anatomy education. This article constructs a conceptual metaphor between a typical anatomy laboratory and an ecosystem, and considers the affordances, constraints, and changing roles of physical and digital cadavers within anatomy education through an ecological lens. Adaptation of physical and digital cadavers during the disturbance is analyzed, and the resiliency of digital cadaver technology is recognized. The evolving role of the digital cadaver is considered in terms of increasing accessibility and inclusivity within the anatomy laboratory ecosystem of the future.

The Visible Korean: movable surface models of the hip joint

PURPOSE

In this study, we presented movable surface models to help medical students understand the multiaxial movements of the hip joint. The secondary objective was to demonstrate a simple method to make movable surface models for other researchers.

METHODS

We used 166 surface models of the virtual human, and the commercial software was used for all the processes described in this study. Virtual joints were created for the hip joint of the surface models to simulate realistic movements of the joints. Bone surface models were processed to maintain the original shape of the bones during movement. Muscle surface models were processed to express deformation of the muscle shapes during movement. Next, the muscle and bone surface models were moved over six movements of the hip joint (flexion, extension, abduction, adduction, lateral rotation, and medial rotation). The surface models of these six movements were saved and packaged in a PDF file.

RESULTS

The PDF file enabled users to see the stereoscopic shapes of the bones and muscles of the hip joint and to scrutinize the six movements on the X, Y, and Z axes of the joint.

CONCLUSION

The movable surface models of the hip joint of this study will be helpful for medical students to learn the multiaxial movements of the hip joint. We expect to develop simulations of other joints that can be used in the education of medical students using the materials and methods described in this study.

The Impact of Acoustic Clutter on Large Array Abdominal Imaging

Abdominal imaging suffers from a particularly difficult acoustic environment-targets are located deep and overlying tissue layers with varying properties generate acoustic clutter. Increasing array size can overcome the penetration and lateral resolution problems in ideal conditions, but how the impact of clutter scales with increasing array extent is unknown and may limit the benefits in vivo. Previous ex vivo experimental work showed the promise of large arrays but was technically limited to a length of 6.4 cm and to only partial sampling of the array elements. We present an extension of those studies using the Fullwave simulation tool to create a 10 cm ×2 cm matrix array with full lateral element sampling. We used a numerical model of the abdomen based on the maps of tissue acoustical properties and found that propagation through the modeled abdominal layers generated on average 25.4 ns of aberration and 0.74 cm of reverberation clutter across the array extent. Growing the full aperture from 2 to 10 cm improved contrast by 8.6 dB and contrast-to-noise ratio by 22.9% in addition to significantly improving target resolution. Alternative array strategies that may be useful for implementation-mismatched aperture sizes or a swept synthetic aperture-also produced improved quality with growing aperture size. These results motivate the development of larger diagnostic imaging arrays for the purpose of high-resolution imaging in challenging environments.

The myodural bridge complex defined as a new functional structure

PURPOSE

The connective tissue between suboccipital muscles and the cervical spinal dura mater (SDM) is known as the myodural bridge (MDB). However, the adjacent relationship of the different connective tissue fibers that form the MDB remains unclear. This information will be highly useful in exploring the function of the MDB.

METHODS

The adjacent relationship of different connective tissue fibers of MDB was demonstrated based upon three-dimensional visualization model, P45 plastinated slices and histological sections of human MDB.

RESULTS

We found that the MDB originating from the rectus capitis posterior minor muscle (RCPmi), rectus capitis posterior major muscle (RCPma) and obliquus capitis inferior muscle (OCI) in the suboccipital region coexists. Part of the MDB fibers originate from the ventral aspect of the RCPmi and, together with that from the cranial segment of the RCPma, pass through the posterior atlanto-occipital interspace (PAOiS) and enter into the posterior aspect of the upper cervical SDM. Also, part of the MDB fibers originate from the dorsal aspect of the RCPmi, the ventral aspect of the caudal segment of the RCPma, and the ventral aspect of the medial segment of the OCI, enter the central part of the posterior atlanto-axial interspace (PAAiS) and fuse with the vertebral dura ligament (VDL), which connects with the cervical SDM.

CONCLUSIONS

Our findings prove that the MDB exists as a complex structure which we termed the 'myodural bridge complex' (MDBC). In the process of head movement, tensile forces could be transferred possibly and effectively by means of the MDBC. The concept of MDBC will be beneficial in the overall exploration of the function of the MDB.

Three-dimensional biomimetic head model as a platform for thermal testing of protective goggles for prevention of eye injuries

BACKGROUND

The rate of eye injury is steadily rising during military conflicts of the century, with thermal burns being the most common type of injury to the eyes. The present study focuses on assessing the heat resistance properties of military protective goggles using three-dimensional (3D) finite element head modeling fitted with the tested protective gear.

METHODS

A computational thermal impact was applied onto a 3D biomimetic human head model fitted with two goggle models - sports (Type 1) and square (Type 2). The resultant temperature of the eye tissues and the thermal injury thresholds were calculated by using the modeling, hence allowing to determine the protective efficacy of the goggles objectively, in a standardized, quantitative and cost-effective manner.

FINDINGS

Both types of goggles had a dramatic protective effect on the eyes. The specific goggle geometry had no notable effect on the level of protection to the inner tissues against the thermal insult. At the skin level goggles reduced temperatures by ~64% under the impact zone, with only a mild difference (10 °C) between the goggles.

INTERPRETATION

Little limitations on the shape and geometry of goggles were observed and any structure of goggles can provide an adequate protection against a thermal insult (per se) to inner cranial tissues, assuming the lenses are wide and thick enough to block direct skin contact of the heat insult. It was shown that our 3D biomimetic human head model provides a practical and cost-effective tool for determining the performance level of goggles with different attributed (i.e., shapes and thermal properties).

A comparative biomechanical analysis of suprapectineal and infrapectineal fixation on acetabular anterior column fracture by finite element modeling

Background/aim

The aim of this study is to compare the stability and implant stresses of suprapectineal plate with infrapectineal plate in three subconfigurations of the screw types.

Materials and methods

The stabilities of different fixation methods were compared by finite element analysis on six models. Three infrapectineal and three suprapectineal models each with locked, unlocked, or combined screws were employed. Three-dimensional finite element stress analysis was performed by using isotropic materials with a load of 2.3 kN applied at standing positions. Motion at the fracture line was measured on four different points located on the pubic and iliac sides of the fracture line.

Results

Infrapectineal plate fixation with unlocked screws was found to be the most stable fixation method with 0.006 mm displacement of fragments in all axes at standing positions. The suprapectineal unlocked method was found to be the most unstable in standing positions with maximum displacement values of 0.46 mm vertical shear movement in the x-axis, –0.14 mm displacement in the y-axis, and –0.33 mm lateral shear in the z-axis.

Conclusion

The infrapectineal unlocked plate supplies the most stable fixation with the least implant stress, contrary to the suprapectineal unlocked plate, which has the lowest stability and highest implant stresses.

Physical and Computer Modelling of Blood Flow in a Systemic-to-pulmonary Shunt

The aim of this work was the application of computer and physical in vitro simulation methods for estimating surgery procedure hemodynamics. The modified Blalock-Taussig (mB-T) palliative surgical procedure is performed to increase the pulmonary blood flow in children with congenital heart defects. Such a systemic-to-pulmonary shunt yields substantial modification in the blood flow within the large blood vessels. The objective of the present study was to investigate basic characteristics of the flow, flow pattern and pressure-flow efficiency, before and after opening of the mB-T graft.

Methods

The model was based on the vessel geometry obtained from the Visible Human Project and included the arch of aorta, the three arteries branching from the arch, the pulmonary trunck, and the left and right pulmonary arteries. The graft was added between the left subclavian artery and the left pulmonary artery. The glass model of the vessels was produced and investigated in a physical model of the cardiovascular system with an artificial ventricular device as the blood pump. Flow rate and hydrostatic pressure were measured at the inlet to and outlets from the glass model and in a few points within the system. Laser flow visualization was also performed. Computer simulations were done using the boundary conditions from the physical model.

Results

The opening of the mB-T graft changed flow distribution in all branches (including inflow). A complex flow pattern with large eddies and channelling of the flow in the vicinity of the graft and within it was observed in flow visualization and in computer simulations. Because of that complexity the local measurements of hydrostatic pressure at the vessel wall could not predict the average flow rate. The reversed flow in the graft was observed during the systole.

Conclusions

The complex flow pattern developed in the physical model of the mB-T graft. The channelling of the flow and the formation of large eddies may yield high shear stress and modify blood properties. The rigid wall model can describe only some flow characteristics observed in vivo. Computer simulation is a very fast and accurate method which permits earlier qualification of cardiac surgeons on how to change cardiac vascular blood flow after operations.

A comparison of two anatomical body models derived from the female visible human project data

Two electromagnetic human body models independently developed from the same image dataset-the voxel-based AustinWoman and surface-based VHP-Female models- are compared. In addition to contrasting volumes and crosssection images of their tissues, the power absorbed by the two models under plane-wave excitation is also compared. Five different numerical methods are used to compute the absorbed power and to evaluate modeling and computational errors.

The Visible Human Project male CAD based computational phantom and its use in bioelectromagnetic simulations

Use of numerical simulation tools to provide qualitative estimates on electromagnetic safety, characterize antenna performance for WBAN applications and facilitate ground breaking research on diagnostic and therapeutic bioelectrical solutions has steadily grown over the past twenty years. However, the accuracy and applicability of such tools are directly proportional to the fidelity of the model used during the simulation. This paper describes the construction of a new CAD based male computational phantom, the Visible Human Project (VHP)-Male model, suitable for use in major commercial electromagnetics simulation packages.

The Visible Human Project: From Body to Bits

Atlases of anatomy have long been a mainstay for visualizing and identifying features of the human body [1]. Many are constructed of idealized illustrations rendered so that structures are presented as three-dimensional (3-D) pictures. Others have employed photographs of actual dissections. Still others are composed of collections of artist renderings of organs or areas of interest. All rely on a basically two-dimensional (2-D) graphic display to depict and allow for a better understanding of a complicated 3-D structure.

Computational human model VHP-FEMALE derived from datasets of the national library of medicine

Simulation of the electromagnetic response of the human body relies upon efficient computational models. The objective of this paper is to describe a new platform-independent and computationally-efficient full-body electromagnetic model, the Visible Human Project® (VHP)-Female v.3.0 and to outline its distinct features. We also report model performance results using two leading commercial electromagnetic antenna simulation packages: ANSYS HFSS and CST MICROWAVE STUDIO®.

VHP-Female full-body human CAD model for cross-platform FEM simulations: recent development and validations

Simulation of the electromagnetic response of the human body relies heavily upon efficient computational models or phantoms. The first objective of this paper is to present an improved platform-independent full-body electromagnetic computational model (computational phantom), the Visible Human Project® (VHP)-Female v. 3.1 and to describe its distinct features and enhancements compared to VHP-Female v. 2.0. The second objective is to report phantom simulation for electric stimulation studies using the commercial FEM electromagnetic solver ANSYS MAXWELL.

AustinMan and AustinWoman: High-fidelity, anatomical voxel models developed from the VHP color images

The current versions (v2.3) of AustinMan and AustinWoman anatomical voxel models are presented with the methodology used to generate them from the Visible Human Project's color cross-sectional anatomical images. Both models are freely available online and documented in detail to increase their reproducibility. Visualizations of the models are shown to highlight their complexity.

The visible human project®: From body to bits

In the middle 1990's the U.S. National Library sponsored the acquisition and development of the Visible Human Project® data base. This image database contains anatomical cross-sectional images which allow the reconstruction of three dimensional male and female anatomy to an accuracy of less than 1.0 mm. The male anatomy is contained in a 15 gigabyte database, the female in a 39 gigabyte database. This talk will describe why and how this project was accomplished and demonstrate some of the products which the Visible Human dataset has made possible. I will conclude by describing how the Visible Human Project, completed over 20 years ago, has led the National Library of Medicine to a series of image research projects including an open source image processing toolkit which is included in several commercial products.

Planar Visualization of Treelike Structures

We present a novel method to create planar visualizations of treelike structures (e.g., blood vessels and airway trees) where the shape of the object is well preserved, allowing for easy recognition by users familiar with the structures. Based on the extracted skeleton within the treelike object, a radial planar embedding is first obtained such that there are no self-intersections of the skeleton which would have resulted in occlusions in the final view. An optimization procedure which adjusts the angular positions of the skeleton nodes is then used to reconstruct the shape as closely as possible to the original, according to a specified view plane, which thus preserves the global geometric context of the object. Using this shape recovered embedded skeleton, the object surface is then flattened to the plane without occlusions using harmonic mapping. The boundary of the mesh is adjusted during the flattening step to account for regions where the mesh is stretched over concavities. This parameterized surface can then be used either as a map for guidance during endoluminal navigation or directly for interrogation and decision making. Depth cues are provided with a grayscale border to aid in shape understanding. Examples are presented using bronchial trees, cranial and lower limb blood vessels, and upper aorta datasets, and the results are evaluated quantitatively and with a user study.

Digital human modeling and its applications: Review and future prospects

OBJECTIVE

The digital human modeling combines information technology with bioscience, applied to analog study from DNA molecule and protein to cell and tissue, as well as organ. It has been widely implemented in various fields such as aviation, national defense, film and television, sports and medical treatment. This paper sorts relative research achievements and progress in recent years and summarizes issues and challenges of research work. The purpose of this paper is to provide references for the development of Digital Human Modeling.

METHODS

Basing on the development plans proposed by Federation of American Scientists (FAS) and current theories, we sorted academic achievements and relative references since the beginning of the digital human concept until 2014 into four aspects, which were named as Visible Human, Virtual Physical Human, Virtual Physiological Human, and Intelligent Virtual Human. We collected information of data acquisition, data analysis and dataset establishment for Visible Human. We outlined the Virtual Physical Human references in four physical categories, including radiation, ultrasonic, electrics, and mechanics. For Virtual Physiological Human, relative researches related to the physiological and biochemical changes of human body were categorized in four aspects as gene molecules, cells, and organs. Relative researches of Virtual Brain Human were mainly concentrated on virtual human brain and virtual human control.

RESULTS

According to the differences in investigations and applications requirements of Digital Human in all aspects, we classified, analyzed and concluded extensive preference data. The overall plan of Digital Human, as well as technical routes, work plans, present states, goals, results and application value in each stage of research was summarized. We discussed the technical issues existing in each aspect of Digital Human, along with the urgent key technologies including data collection, data processing, and modeling.

CONCLUSION

Analyzing the core technologies and the general technical schemes in the field of Digital Human, this paper summarizes the technical solutions, research results and technical problems of major researchers. The future prospects of Digital Human are reviewed.

Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering

This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs.

Application of Radial Basis Function Methods in the Development of a 95th Percentile Male Seated FEA Model

Human body finite element models (FEMs) are a valuable tool in the study of injury biomechanics. However, the traditional model development process can be time-consuming. Scaling and morphing an existing FEM is an attractive alternative for generating morphologically distinct models for further study. The objective of this work is to use a radial basis function to morph the Global Human Body Models Consortium (GHBMC) average male model (M50) to the body habitus of a 95th percentile male (M95) and to perform validation tests on the resulting model. The GHBMC M50 model (v. 4.3) was created using anthropometric and imaging data from a living subject representing a 50th percentile male. A similar dataset was collected from a 95th percentile male (22,067 total images) and was used in the morphing process. Homologous landmarks on the reference (M50) and target (M95) geometries, with the existing FE node locations (M50 model), were inputs to the morphing algorithm. The radial basis function was applied to morph the FE model. The model represented a mass of 103.3 kg and contained 2.2 million elements with 1.3 million nodes. Simulations of the M95 in seven loading scenarios were presented ranging from a chest pendulum impact to a lateral sled test. The morphed model matched anthropometric data to within a rootmean square difference of 4.4% while maintaining element quality commensurate to the M50 model and matching other anatomical ranges and targets. The simulation validation data matched experimental data well in most cases.

Real-time advanced spinal surgery via visible patient model and augmented reality system

This paper presents an advanced augmented reality system for spinal surgery assistance, and develops entry-point guidance prior to vertebroplasty spinal surgery. Based on image-based marker detection and tracking, the proposed camera-projector system superimposes pre-operative 3-D images onto patients. The patients' preoperative 3-D image model is registered by projecting it onto the patient such that the synthetic 3-D model merges with the real patient image, enabling the surgeon to see through the patients' anatomy. The proposed method is much simpler than heavy and computationally challenging navigation systems, and also reduces radiation exposure. The system is experimentally tested on a preoperative 3D model, dummy patient model and animal cadaver model. The feasibility and accuracy of the proposed system is verified on three patients undergoing spinal surgery in the operating theater. The results of these clinical trials are extremely promising, with surgeons reporting favorably on the reduced time of finding a suitable entry point and reduced radiation dose to patients.

[Application value of three-dimensional female pelvic visualization modeling on transvaginal gynecological ultrasound imaging]

OBJECTIVE

To explore the application value of three-dimensional (3D) female pelvic visualization model on transvaginal gynecological ultrasound imaging.

METHODS

The second digital Chinese woman visible human datasets was selected, and a female pelvicvoxel-based model was constructed in Amira software for analog simulation combined with transvaginal gynecological ultrasound. The main structures and the space position variation of female pelvic cavity were observed, and the comparison study with conventional section of ultrasound was carried out.

RESULTS

A high accuracy 3D visualization model of female pelvic was successfully constructed, and the anatomy structures can be dynamically and clearly displayed in any section orientation. An analog simulation research was carried out according to the scan mode of gynecological ultrasound, and a series of high resolution images consistent with scan sections of dynamic ultrasound were obtained, which had provided the optimal scan pathway for the fast inspection of the uterus, fallopian tubes and ovaries.

CONCLUSION

The 3D female pelvic visualization model based on digital Chinese woman human datasets has provided detailed and accurate anatomy information for transvaginal gynecological ultrasound imaging, which could be the benefit for doctors to understand the ultrasound images of female pelvic, as well as the accurate positioning ability to the lesions of female pelvic cavity.

Octree rasterization: accelerating high-quality out-of-core GPU volume rendering

We present a novel approach for GPU-based high-quality volume rendering of large out-of-core volume data. By focusing on the locations and costs of ray traversal, we are able to significantly reduce the rendering time over traditional algorithms. We store a volume in an octree (of bricks); in addition, every brick is further split into regular macrocells. Our solutions move the branch-intensive accelerating structure traversal out of the GPU raycasting loop and introduce an efficient empty-space culling method by rasterizing the proxy geometry of a view-dependent cut of the octree nodes. This rasterization pass can capture all of the bricks that the ray penetrates in a per-pixel list. Since the per-pixel list is captured in a front-to-back order, our raycasting pass needs only to cast rays inside the tighter ray segments. As a result, we achieve two levels of empty space skipping: the brick level and the macrocell level. During evaluation and testing, this technique achieved 2 to 4 times faster rendering speed than a current state-of-the-art algorithm across a variety of data sets.

Two-dimensional sectioned images and three-dimensional surface models for learning the anatomy of the female pelvis

In the Visible Korean project, serially sectioned images of the pelvis were made from a female cadaver. Outlines of significant structures in the sectioned images were drawn and stacked to build surface models. To improve the accessibility and informational content of these data, a five-step process was designed and implemented. First, 154 pelvic structures were outlined with additional surface reconstruction to prepare the image data. Second, the sectioned and outlined images (in a browsing software) as well as the surface models (in a PDF file) were placed on the Visible Korean homepage in a readily-accessible format. Third, all image data were visualized with interactive elements to stimulate creative learning. Fourth, two-dimensional (2D) images and three-dimensional (3D) models were superimposed on one another to provide context and spatial information for students viewing these data. Fifth, images were designed such that structure names would be shown when the mouse pointer hovered over the 2D images or the 3D models. The state-of-the-art sectioned images, outlined images, and surface models, arranged and systematized as described in this study, will aid students in understanding the anatomy of female pelvis. The graphic data accompanied by corresponding magnetic resonance images and computed tomographs are expected to promote the production of 3D simulators for clinical practice.

A three-dimensional atlas of human tongue muscles

The human tongue is one of the most important yet least understood structures of the body. One reason for the relative lack of research on the human tongue is its complex anatomy. This is a real barrier to investigators as there are few anatomical resources in the literature that show this complex anatomy clearly. As a result, the diagnosis and treatment of tongue disorders lags behind that for other structures of the head and neck. This report intended to fill this gap by displaying the tongue's anatomy in multiple ways. The primary material used in this study was serial axial images of the male and female human tongue from the Visible Human (VH) Project of the National Library of Medicine. In addition, thick serial coronal sections of three human tongues were rendered translucent. The VH axial images were computer reconstructed into serial coronal sections and each tongue muscle was outlined. These outlines were used to construct a three-dimensional (3D) computer model of the tongue that allows each muscle to be seen in its in vivo anatomical position. The thick coronal sections supplement the 3D model by showing details of the complex interweaving of tongue muscles throughout the tongue. The graphics are perhaps the clearest guide to date to aid clinical or basic science investigators in identifying each tongue muscle in any part of the human tongue.

Anatomical education and surgical simulation based on the Chinese Visible Human: a three-dimensional virtual model of the larynx region

Anatomical knowledge of the larynx region is critical for understanding laryngeal disease and performing required interventions. Virtual reality is a useful method for surgical education and simulation. Here, we assembled segmented cross-section slices of the larynx region from the Chinese Visible Human dataset. The laryngeal structures were precisely segmented manually as 2D images, then reconstructed and displayed as 3D images in the virtual reality Dextrobeam system. Using visualization and interaction with the virtual reality modeling language model, a digital laryngeal anatomy instruction was constructed using HTML and JavaScript languages. The volume larynx models can thus display an arbitrary section of the model and provide a virtual dissection function. This networked teaching system of the digital laryngeal anatomy can be read remotely, displayed locally, and manipulated interactively.

The biomechanics of the human tongue

The human tongue is composed mainly of skeletal muscle tissue and has a complex architecture. Its anatomy is characterised by interweaving yet distinct muscle groups. It is a significant contributor to the phenomenon of obstructive sleep apnoea syndrome. A realistic model of the tongue and computational simulations are important in areas such as linguistics and speech therapy. The aim of this work is to report on the construction of a geometric and constitutive model of the human tongue and to demonstrate its use in computational simulations for obstructive sleep apnoea syndrome research. The geometry of the tongue and each muscle group of the tongue, including muscle fibre orientations, are captured from the Visible Human Project dataset. The fully linear muscle model is based on the Hill three-element model that represents the constituent parts of muscle fibres. The mechanics of the model are limited to quasi-static, small-strain, linear-elastic behaviour. The main focus of this work is on the material directionality and muscle activation. The transversely isotropic behaviour of the muscle tissue is accounted for, as well as the influence of muscle activation. The behaviour of the model is illustrated in a number of benchmark tests and for the case of a subject in the supine position.

Construction of boundary-surface-based Chinese female astronaut computational phantom and proton dose estimation

With the rapid development of China's space industry, the importance of radiation protection is increasingly prominent. To provide relevant dose data, we first developed the Visible Chinese Human adult Female (VCH-F) phantom, and performed further modifications to generate the VCH-F Astronaut (VCH-FA) phantom, incorporating statistical body characteristics data from the first batch of Chinese female astronauts as well as reference organ mass data from the International Commission on Radiological Protection (ICRP; both within 1% relative error). Based on cryosection images, the original phantom was constructed via Non-Uniform Rational B-Spline (NURBS) boundary surfaces to strengthen the deformability for fitting the body parameters of Chinese female astronauts. The VCH-FA phantom was voxelized at a resolution of 2 × 2 × 4 mm(3)for radioactive particle transport simulations from isotropic protons with energies of 5000-10 000 MeV in Monte Carlo N-Particle eXtended (MCNPX) code. To investigate discrepancies caused by anatomical variations and other factors, the obtained doses were compared with corresponding values from other phantoms and sex-averaged doses. Dose differences were observed among phantom calculation results, especially for effective dose with low-energy protons. Local skin thickness shifts the breast dose curve toward high energy, but has little impact on inner organs. Under a shielding layer, organ dose reduction is greater for skin than for other organs. The calculated skin dose per day closely approximates measurement data obtained in low-Earth orbit (LEO).

[The potential of three-dimensional simulation as the method for situational reconstruction of the gunshot injury mechanism]

A method for the three-dimensional modeling is proposed designed to enhance the objective value of situational expert investigations of the mechanism of gunshot wounds. The method was successfully validated in a number of forensic medical situational studies and allowed their objectiveness, demonstrativeness, and evidentiary force to be significantly improved.

Mechanics of the foot Part 2: A coupled solid-fluid model to investigate blood transport in the pathologic foot

A coupled computational model of the foot consisting of a three-dimensional soft tissue continuum and a one-dimensional (1D) transient blood flow network is presented in this article. The primary aim of the model is to investigate the blood flow in major arteries of the pathologic foot where the soft tissue stiffening occurs. It has been reported in the literature that there could be up to about five-fold increase in the mechanical stiffness of the plantar soft tissues in pathologic (e.g. diabetic) feet compared with healthy ones. The increased stiffness results in higher tissue hydrostatic pressure within the plantar area of the foot when loaded. The hydrostatic pressure acts on the external surface of blood vessels and tend to reduce the flow cross-section area and hence the blood supply. The soft tissue continuum model of the foot was modelled as a tricubic Hermite finite element mesh representing all the muscles, skin and fat of the foot and treated as incompressible with transversely isotropic properties. The details of the mechanical model of soft tissue are presented in the companion paper, Part 1. The deformed state of the soft tissue continuum because of the applied ground reaction force at three foot positions (heel-strike, midstance and toe-off) was obtained by solving the Cauchy equations based on the theory of finite elasticity using the Galerkin finite element method. The geometry of the main arterial network in the foot was represented using a 1D Hermite cubic finite element mesh. The flow model consists of 1D Navier-Stokes equations and a nonlinear constitutive equation to describe vessel radius-transmural pressure relation. The latter was defined as the difference between the fluid and soft tissue hydrostatic pressure. Transient flow governing equations were numerically solved using the two-step Lax-Wendroff finite difference method. The geometry of both the soft tissue continuum and arterial network is anatomically-based and was developed using the data derived from visible human images and magnetic resonance images of a healthy male volunteer. Simulation results reveal that a two-fold increase in tissue stiffness leads to about 28% reduction in blood flow to the affected region.

Mechanics of the foot Part 1: a continuum framework for evaluating soft tissue stiffening in the pathologic foot

Soft tissue stiffening is a common mechanical observation reported in foot pathologies including diabetes mellitus and gout. These material changes influence the spatial distribution of stress and affect blood flow, which is essential to nutrient entry and waste removal. An anatomically-based subject-specific foot model was developed to explore the influence of tissue stiffening on plantar pressure and internal von Mises stress at heel-strike, midstance and toe-off. This work draws on the model database developed for the Physiome project consisting of muscles, bones, soft tissue and other structures such as sensory nerves. The anisotropic structure of soft tissue was embedded in a single continuum as an efficient model for finite soft tissue deformation, and customisation methods were used to capture the unique foot profile. The model was informed by kinetics from an instrumented treadmill and kinematics from motion capture, synchronised together. Foot sole pressure predictions were evaluated against a commercial pressure platform. Key outcomes showed that internal stress can be up to 1.6 times the surface pressure with implications for internal soft tissue damage not observed at the surface. The main nerve branch stimulated during gait was the lateral plantar nerve. This subject-specific modelling framework can play an integral part in therapeutic treatments by informing assistive strategies such as mechanical noise stimulation and orthotics.

[3-dimensional visualization study of angle nerve of facial nerve]

OBJECTIVE

To validate the previous anatomic study result about angle nerve of facial nerve through 3-dimensional (3-D) visualization technique, so as to provide theory basis for clinic treatment of nerve loss.

METHOD

The full-thickness soft tissue at internal side of inner canthus was harvested from adult cadaveric head. The skin was 3 cm in length and 1 cm in width, with 2 parallel cut lines as location markers. The specimen was sliced continuously into 120 slices, with 10 microm in thickness for every slice, 0.25 mm apart. The slices underwent HE staining and 2-D digital image was gained by high resolution scanner. Then 3-D reconstruction was performed.

RESULTS

(1) It showed the 3-D structures and routes of angle nerve, as well as the relationship between angle nerve and angle arteriovenous. All the reconstructed structures can be displayed together or separately, also from any angles. (2) It confirmed the accuracy of microscopic anatomy study about angle nerve. (3) The 3-D reconstruction of angle nerve, as well as the surrounding structure could be very useful for clinical application.

CONCLUSION

Based on the histologic study and computer technology, the 3-D reconstruction of angle nerve could provide accurate basis for the feasibility of clinic treatment of angle nerve loss.

Visualizing cells and humans in 3D: biomedical image analysis at nanometer and meter scales

Researchers analyzed and presented volume data from the Visible Human Project (VHP) and data from high-resolution 3D ion-abrasion scanning electron microscopy (IA-SEM). They acquired the VHP data using cryosectioning, a destructive approach to 3D human anatomical imaging resulting in whole-body images with a field of view approaching 2 meters and a minimum resolvable feature size of 300 microns. IA-SEM is a type of block-face imaging microscopy, a destructive approach to microscopic 3D imaging of cells. The field of view of IA-SEM data is on the order of 10 microns (whole cell) with a minimum resolvable feature size of 15 nanometers (single-slice thickness). Despite the difference in subject and scale, the analysis and modeling methods were remarkably similar. They are derived from image processing, computer vision, and computer graphics techniques. Moreover, together we are employing medical illustration, visualization, and rapid prototyping to inform and inspire biomedical science. By combining graphics and biology, we are imaging across nine orders of magnitude of space to better promote public health through research.

Theoretical study for safe and efficient energy transfer to deeply implanted devices using ultrasound

The goal of this paper is to prove that a safe and efficient energy transfer is possible between an external transducer located on the patient's skin and a device deeply implanted in the abdomen. An ultrasound propagation model based on the Rayleigh-Sommerfeld diffraction integral is coupled with the data from the Visible Human Project to account for the geometry of the organs in the body. The model is able to predict the amount of acoustic power received by the device for different acoustic paths. The acoustic model is validated by comparison with measurements in water and in heterogeneous liquid phantoms. Care is taken to minimize adverse bioeffects-mainly temperature rise and cavitation in tissues. Simulations based on the bio-heat transfer equation are performed to check that thermal effects are indeed small.

Creation of a female and male segmentation dataset based on Chinese Visible Human (CVH)

OBJECTIVE

Segmentation is a necessary step when creating realistic three-dimensional (3D) models. In order to build 3D models of whole body structures and have a wider lateral application, the thin sectional anatomical images of the Chinese Visible Human (CVH) dataset should be segmented. The more detailed structures are segmented to provide greater potential for wider application of the segmented images.

MATERIALS AND METHODS

All the images based on the CVH male and female dataset were segmented semi-automatically using PHOTOSHOP software. This research lasted about 7 years.

RESULT

In this study, 869 structures of CVH male and 860 structures of CVH female were semi-automatically segmented, and the formats for the segmented color-filled image data were PSD and PNG. In these segmented structures, nearly all skeletal muscles included muscle belly and tendon, and hollow organs included their organ walls and their lumen. Most nerve trunks, small arteries, lymph nodes, and lymph ducts were also segmented. Many surface-rendering and volume-rendering organ models were created using these segmented images.

CONCLUSION

The CVH male and female images represent the normal Asian population. After segmentation, the images can be reconstructed directly in 3D and greatly facilitate the biological modeling of physical and physiological information, a great help in improving medical and biological science in China.

The use of virtual patients in medical school curricula

The demonstration of patient-based cases using automated technology [virtual patients (VPs)] has been available to health science educators for a number of decades. Despite the promise of VPs as an easily accessible and moldable platform, their widespread acceptance and integration into medical curricula have been slow. Here, the authors review the technological underpinnings of VPs, summarize the literature regarding the use and limitations of VPs in the healthcare curriculum, describe novel possible applications of the technology, and propose possible directions for future work.

Computational model of soft tissues in the human upper airway

This paper presents a three-dimensional finite element model of the tongue and surrounding soft tissues with potential application to the study of sleep apnoea and of linguistics and speech therapy. The anatomical data was obtained from the Visible Human Project, and the underlying histological data was also extracted and incorporated into the model. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group was determined through the use of a genetic algorithm-based neural control model. The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus.

Visualization of the left extraperitoneal space and spatial relationships to its related spaces by the visible human project

BACKGROUND

The major hindrance to multidetector CT imaging of the left extraperitoneal space (LES), and the detailed spatial relationships to its related spaces, is that there is no obvious density difference between them. Traditional gross anatomy and thick-slice sectional anatomy imagery are also insufficient to show the anatomic features of this narrow space in three-dimensions (3D). To overcome these obstacles, we used a new method to visualize the anatomic features of the LES and its spatial associations with related spaces, in random sections and in 3D.

METHODS

In conjunction with Mimics® and Amira® software, we used thin-slice cross-sectional images of the upper abdomen, retrieved from the Chinese and American Visible Human dataset and the Chinese Virtual Human dataset, to display anatomic features of the LES and spatial relationships of the LES to its related spaces, especially the gastric bare area. The anatomic location of the LES was presented on 3D sections reconstructed from CVH2 images and CT images.

PRINCIPAL FINDINGS

What calls for special attention of our results is the LES consists of the left sub-diaphragmatic fat space and gastric bare area. The appearance of the fat pad at the cardiac notch contributes to converting the shape of the anteroexternal surface of the LES from triangular to trapezoidal. Moreover, the LES is adjacent to the lesser omentum and the hepatic bare area in the anterointernal and right rear direction, respectively.

CONCLUSION

The LES and its related spaces were imaged in 3D using visualization technique for the first time. This technique is a promising new method for exploring detailed communication relationships among other abdominal spaces, and will promote research on the dynamic extension of abdominal diseases, such as acute pancreatitis and intra-abdominal carcinomatosis.

Browsing software of the Visible Korean data used for teaching sectional anatomy

The interpretation of computed tomographs (CTs) and magnetic resonance images (MRIs) to diagnose clinical conditions requires basic knowledge of sectional anatomy. Sectional anatomy has traditionally been taught using sectioned cadavers, atlases, and/or computer software. The computer software commonly used for this subject is practical and efficient for students but could be more advanced. The objective of this research was to present browsing software developed from the Visible Korean images that can be used for teaching sectional anatomy. One thousand seven hundred and two sets of MRIs, CTs, and sectioned images (intervals, one millimeter) of a whole male cadaver were prepared. Over 900 structures in the sectioned images were outlined and then filled with different colors to elaborate each structure. Software was developed where four corresponding images could be displayed simultaneously; in addition, the structures in the image data could be readily recognized with the aid of the color-filled outlines. The software, distributed free of charge, could be a valuable tool to teach medical students. For example, sectional anatomy could be taught by showing the sectioned images with real color and high resolution. Students could then review the lecture by using the sectioned and color-filled images on their own computers. Students could also be evaluated using the same software. Furthermore, other investigators would be able to replace the images for more comprehensive sectional anatomy.

E-learning used in a training course on atraumatic restorative treatment (ART) for Brazilian dentists

The purpose of this study was to assess the benefits of using e-learning resources in a dental training course on Atraumatic Restorative Treatment (ART). This e-course was given in a DVD format, which presented the ART technique and philosophy. The participants were twenty-four dentists from the Brazilian public health system. Prior to receiving the DVD, the dentists answered a questionnaire regarding their personal data, previous knowledge about ART, and general interest in training courses. The dentists also participated in an assessment process consisting of a test applied before and after the course. A single researcher corrected the tests, and intraexaminer reproducibility was calculated (kappa=0.89). Paired t-tests were carried out to compare the means between the assessments, showing a significant improvement in the performance of the subjects on the test taken after the course (p<0.05). A linear regression model was used with the difference between the means as the outcome. A greater improvement on the test results was observed among female dentists (p=0.034), dentists working for a shorter period of time in the public health system (p=0.042), and dentists who used the ART technique only for urgent and/or temporary treatment (p=0.010). In conclusion, e-learning has the potential of improving the knowledge that dentists working in the public health system have about ART, especially those with less clinical experience and less knowledge about the subject.

Visualization of light propagation in visible Chinese human head for functional near-infrared spectroscopy

Using the visible Chinese human data set, which faithfully represents human anatomy, we visualize the light propagation in the head in detail based on Monte Carlo simulation. The simulation is verified to agree with published experimental results in terms of a differential path-length factor. The spatial sensitivity profile turns out to seem like a fat tropical fish with strong distortion along the folding cerebral surface. The sensitive brain region covers the gray matter and extends to the superficial white matter, leading to a large penetration depth (>3 cm). Finally, the optimal source-detector separation is suggested to be narrowed down to 3-3.5 cm, while the sensitivity of the detected signal to brain activation reaches the peak of 8%. These results indicate that the cerebral cortex folding geometry actually has substantial effects on light propagation, which should be necessarily considered for applications of functional near-infrared spectroscopy.

Development of a computer-assisted cranial nerve simulation from the visible human dataset

Advancements in technology and personal computing have allowed for the development of novel teaching modalities such as online web-based modules. These modules are currently being incorporated into medical curricula and, in some paradigms, have been shown to be superior to classroom instruction. We believe that these modules have the potential of significantly enriching anatomy education by helping students better appreciate spatial relationships, especially in areas of the body with greater anatomical complexity. Our objective was to develop an online module designed to teach the anatomy and function of the cranial nerves. A three-dimensional model of the skull, brainstem, and thalamus were reconstructed using data from the Visible Human Project and Amira®. The paths of the cranial nerves were overlaid onto this 3D reconstruction. Videos depicting these paths were then rendered using a "roller coaster-styled" camera approach. Interactive elements adding textual information and user control were inserted into the video using Adobe Creative Suite® 4, and finally, the module was exported as an Adobe Flash movie to be viewable on Internet browsers. Fourteen Flash-based modules were created in total. The primary user interface comprises a website encoded in HTML/CSS and contains links to each of the 14 Flash modules as well as a user tutorial.

Stereolithographic biomodelling to create tangible hard copies of the ethmoidal labyrinth air cells based on the visible human project

Rapid prototyping (RP), or stereolithography, is a new clinical application area, which is used to obtain accurate three-dimensional physical replicas of complex anatomical structures. The aim of this study was to create tangible hard copies of the ethmoidal labyrinth air cells (ELACs) with stereolithographic biomodelling. The visible human dataset (VHD) was used as the input imaging data. The Surfdriver software package was applied to these images to reconstruct the ELACs as three-dimensional DXF (data exchange file) models. These models were post-processed in 3D-Doctor software for virtual reality modelling language (VRML) and STL (Standard Triangulation Language) formats. Stereolithographic replicas were manufactured in a rapid prototyping machine by using the STL format. The total number of ELACs was 21. The dimensions of the ELACs on the right and left sides were 52.91 x 13.00 x 28.68 mm and 53.79 x 12.42 x 28.55 mm, respectively. The total volume of the ELACs was 4771.1003 mm(3). The mean ELAC distance was 27.29 mm from the nasion and 71.09 mm from the calotte topologically. In conclusion, the combination of Surfdriver and 3D-Doctor could be effectively used for manufacturing 3D solid models from serial sections of anatomical structures. Stereolithographic anatomical models provide an innovative and complementary tool for students, researchers, and surgeons to apprehend these anatomical structures tangibly. The outcomes of these attempts can provide benefits in terms of the visualization, perception, and interpretation of the structures in anatomy teaching and prior to surgical interventions.

CvhSlicer: an interactive cross-sectional anatomy navigation system based on high-resolution Chinese visible human data

We introduce the design and implementation of an interactive system for the navigation of cross-sectional anatomy based on Chinese Visible Human (CVH) data, named CvhSlicer. This system is featured in real-time computation and rendering of high-resolution anatomical images on standard personal computers (PCs) equipped with commodity Graphics Processing Units (GPUs). In order to load the whole-body dataset into the memory of a common PC, several processing steps are first applied to compress the huge CVH data. Thereafter, an adaptive CPU-GPU balancing scheme is performed to dynamically distribute rendering tasks among CPU and GPU based on parameters of computing resources. Experimental results demonstrate that our system can achieve real-time performance and has great potential to be used in anatomy education.

[The virtual reality simulation research of China Mechanical Virtual Human based on the Creator/Vega]

The China Mechanical Virtual Human (CMVH) is a human musculoskeletal biomechanical simulation platform based on China Visible Human slice images; it has great realistic application significance. In this paper is introduced the construction method of CMVH 3D models. Then a simulation system solution based on Creator/Vega is put forward for the complex and gigantic data characteristics of the 3D models. At last, combined with MFC technology, the CMVH simulation system is developed and a running simulation scene is given. This paper provides a new way for the virtual reality application of CMVH.

[Development of the first head finite element model based on Chinese visible human data]

The second Chinese visible human (CVH) data has been used to build a more precise finite element model of Chinese head via 3-D image reconstruction, solid model reconstruction, finite element meshing, and assembling of finite element model. This second case of finite element model of Chinese head contains skull, facial bones, inferior maxilla, cerebral falx, brain, cerebellum brainstem, and so on. All the mesh elements, according to their main quality check results in line with the engineering requirements, were identified as solid elements, and the numbers of nodes and elements were determined to be 31 223 and 19 911 respectively. The model is coincident with the anatomy of human head; and its accuracy in some region, especially in fundus cranii and fundus cranii, is more excellent than that of the other models based on CT/MRL The development of the first head finite element model based on CVH data has brought on a remarkable progress in the application of CVH platform.