Computerised 3-D anatomical modelling using plastinates: an example utilising the human heart

Computerised modelling methods have become highly useful for generating electronic representations of anatomical structures. These methods rely on crosssectional tissue slices in databases such as the Visible Human Male and Female, the Visible Korean Human, and the Visible Chinese Human. However, these databases are time consuming to generate and require labour-intensive manual digitisation while the number of specimens is very limited. Plastinated anatomical material could provide a possible alternative to data collection, requiring less time to prepare and enabling the use of virtually any anatomical or pathological structure routinely obtained in a gross anatomy laboratory. The purpose of this study was to establish an approach utilising plastinated anatomical material, specifically human hearts, for the purpose computerised 3-D modelling. Human hearts were collected following gross anatomical dissection and subjected to routine plastination procedures including dehydration (–25oC), defatting, forced impregnation, and curing at room temperature. A graphics pipeline was established comprising data collection with a hand-held scanner, 3-D modelling, model polishing, file conversion, and final rendering. Representative models were viewed and qualitatively assessed for accuracy and detail. The results showed that the heart model provided detailed surface information necessary for gross anatomical instructional purposes. Rendering tools facilitated optional model manipulation for further structural clarification if selected by the user. The use of plastinated material for generating 3-D computerised models has distinct advantages compared to cross-sectional tissue images. (Folia Morphol 2011; 70, 3: 191–196

Quantitative fit analysis of acromion fracture plating systems using three-dimensional anatomical modelling

Background Displaced acromial fractures are challenging to treat. Complex bony anatomy, variable fracture morphology and limitations of available implants present challenges in achieving favourable surgical outcomes. We determined to what extent currently available scapular and clavicular plating systems are able to provide adequate fixation options. Methods Patients presenting to an urban trauma centre with acromial fractures sustained from blunt trauma between 2012 and 2016 were identified (n = 15, 14M / 1F). The fracture patterns were categorized according to location (Type I = 13%, Type II = 27%, Type III = 60%). Computed Tomography (CT) scans were reconstructed to produce three-dimensional (3D) printed anatomical models on which a quantitative fit analysis was performed. Measurements were performed twice, by five separate observers, with fit graded as anatomical fit ( 2mm) or no-fit. Results The anterior clavicle 6 hole plate fitted best in 45.7% of cases. Acromial plates only achieved 27.3%. The acromion short plate together with the lateral clavicle short plates performed the best in Type II fractures. An inter-observer intraclass correlation coefficient (ICC) agreement of 0.974 was obtained. Conclusion The available commercial acromial plating system fails to provide adequate congruency and fit for fixation. Clavicular plates were superior alternative implants. 3D printed anatomical models can be used effectively to assist in templating implants preoperatively

Human motion modeling and simulation by anatomical approach

To instantly generate desired infinite realistic human motion is still a great challenge in virtual human simulation. In this paper, the novel emotion effected motion classification and anatomical motion classification are presented, as well as motion capture and parameterization methods. The framework for a novel anatomical approach to model human motion in a HTR (Hierarchical Translations and Rotations) file format is also described. This novel anatomical approach in human motion modelling has the potential to generate desired infinite human motion from a compact motion database. An architecture for the real-time generation of new motions is also propose

Improving workflow for adaptive proton therapy with predictive anatomical modelling: A proof of concept

PURPOSE: To demonstrate predictive anatomical modelling for improving the clinical workflow of adaptive intensity-modulated proton therapy (IMPT) for head and neck cancer. METHODS: 10 radiotherapy patients with nasopharyngeal cancer were included in this retrospective study. Each patient had a planning CT, weekly verification CTs during radiotherapy and predicted weekly CTs from our anatomical model. Predicted CTs were used to create predicted adaptive plans in advance with the aim of maintaining clinically acceptable dosimetry. Adaption was triggered when the increase in mean dose (Dmean) to the parotid glands exceeded 3Gy(RBE). We compared the accumulated dose of two adaptive IMPT strategies: 1) Predicted plan adaption: One adaptive plan per patient was optimised on a predicted CT triggered by replan criteria. 2) Standard replan: One adaptive plan was created reactively in response to the triggering weekly CT. RESULTS: Statistical analysis demonstrates that the accumulated dose differences between two adaptive strategies are not significant (p>0.05) for CTVs and OARs. We observed no meaningful differences in D95 between the accumulated dose and the planned dose for the CTVs, with mean differences to the high-risk CTV of -1.20%, -1.23% and -1.25% for no adaption, standard and predicted plan adaption, respectively. The accumulated parotid Dmean using predicted plan adaption is within 3Gy(RBE) of the planned dose and 0.31Gy(RBE) lower than the standard replan approach on average. CONCLUSION: Prediction-based replanning could potentially enable adaptive therapy to be delivered without treatment gaps or sub-optimal fractions, as can occur during a standard replanning strategy, though the benefit of using predicted plan adaption over the standard replan was not shown to be statistically significant with respect to accumulated dose in this study. Nonetheless, a predictive replan approach can offer advantages in improving clinical workflow efficiency

Characterisation of soft tissue and skeletal bullet wound trauma and three-dimensional anatomical modelling

Effects of firearm projectiles causing injuries to human vital organs were investigated. In this study, the effects of high and medium velocity projectiles on thoracic organs (hearts and lungs) and abdominal organs (livers and kidneys) were investigated using fresh porcine organs and tissue simulants. Furthermore, characteristics of wounds caused by bullets to the cranium, ribs, sternum, vertebrae, scapula and pelvis were analysed. The direction of bullet entry, the manner of death and the mechanisms that caused bone injuries were also determined. A mounted, remotely operated firearm was used to fire a spherical projectile at 900m/s and 500m/s. Doppler radar, infrared sighting screens and high-speed video cameras were used to determine the velocities of the projectiles during their passage through 50mm cubes of fresh porcine lungs, livers, kidneys and hearts, and ballistic tissue simulants. The organs were tested at room (16°C) and core body (37°C) temperature. Time and temperature associated changes in porcine organs were histologically analysed. Two skeletal collections with documented cases of firearm trauma were used for skeletal analyses. Energy loss from projectiles penetrating porcine organs tested at 16°C and 37°C were not significantly different. Histological features of porcine organs did not change during the time of heating from refrigeration to core body temperatures. The energy loss from projectiles penetrating organ simulants at the two tested velocities were different from those measured in porcine organs. This may be the result of differences in densities between the simulants and porcine organs. In skull bones, shape and extent of wounds varied according to the projectile entry energy. Small nicks, circular wounds, or butterfly-like mid-shaft and comminuted fractures were seen in ribs. Injuries in the sternum and ilium were circular in appearance. In the vertebrae, shattering of the vertebral bodies, small fractures and missing segments of the pedicles occurred. Wound characteristics of scapulae varied according to the bone thickness across the scapula. Circular wounds with/without internal bevelling and larger irregularly shaped injuries with/without external bevelling were identified as entry and exit wounds, respectively. High velocity projectiles caused radiating and concentric fractures in brain cases. Skeletal wound characteristics, location and number of wounds, and projectile path allowed the determination of the manner of death. Fracture patterns varied according to the physical properties of bone and projectile entry energy. Re-heating of organs to core body temperature in ballistic research was not necessary. Furthermore, 50mm cubes of organ tissue were adequate to significantly reduce the projectile velocity from entry to exit. New organ simulants with densities similar to soft tissues of human organs or simulants where the density could be altered to match that of the test organ should be used in future ballistic research. Simulants used to represent bone should behave like fresh bone. Accurate information generated by such simulants is of value for the construction of digital programmes or 3D-models to predict how different types of ammunition fired from a variety of firearms cause injury to the human body. They will also be valuable in the development of new ammunitions, firearms, protective body armour and medical treatment of such injuries.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, Adelaide Medical School, 201

The residual STL volume as a metric to evaluate accuracy and reproducibility of anatomic models for 3D printing: application in the validation of 3D-printable models of maxillofacial bone from reduced radiation dose CT images.

BackgroundThe effects of reduced radiation dose CT for the generation of maxillofacial bone STL models for 3D printing is currently unknown. Images of two full-face transplantation patients scanned with non-contrast 320-detector row CT were reconstructed at fractions of the acquisition radiation dose using noise simulation software and both filtered back-projection (FBP) and Adaptive Iterative Dose Reduction 3D (AIDR3D). The maxillofacial bone STL model segmented with thresholding from AIDR3D images at 100 % dose was considered the reference. For all other dose/reconstruction method combinations, a "residual STL volume" was calculated as the topologic subtraction of the STL model derived from that dataset from the reference and correlated to radiation dose.ResultsThe residual volume decreased with increasing radiation dose and was lower for AIDR3D compared to FBP reconstructions at all doses. As a fraction of the reference STL volume, the residual volume decreased from 2.9 % (20 % dose) to 1.4 % (50 % dose) in patient 1, and from 4.1 % to 1.9 %, respectively in patient 2 for AIDR3D reconstructions. For FBP reconstructions it decreased from 3.3 % (20 % dose) to 1.0 % (100 % dose) in patient 1, and from 5.5 % to 1.6 %, respectively in patient 2. Its morphology resembled a thin shell on the osseous surface with average thickness <0.1 mm.ConclusionThe residual volume, a topological difference metric of STL models of tissue depicted in DICOM images supports that reduction of CT dose by up to 80 % of the clinical acquisition in conjunction with iterative reconstruction yields maxillofacial bone models accurate for 3D printing

Anatomical Modelling of the Musculoskeletal System from MRI

Abstract. This paper presents a novel approach for multi-organ (mus-culoskeletal system) automatic registration and segmentation from clini-cal MRI datasets, based on discrete deformable models (simplex meshes). We reduce the computational complexity using multi-resolution forces, multi-resolution hierarchical collision handling and large simulation time steps (implicit integration scheme), allowing real-time user control and cost-efficient segmentation. Radial forces and topological constraints (at-tachments) are applied to regularize the segmentation process. Based on a medial axis constrained approximation, we efficiently characterize shapes and deformations. We validate our methods for the hip joint and the thigh (20 muscles, 4 bones) on 4 datasets: average error=1.5mm, computation time=15min.

Effective skill refinement: Focusing on process to ensure outcome

In contrast to the abundance of motor skill acquisition and performance research, there is a paucity of work which addresses how athletes with an already learnt and well-established skill may go about making a subtle change, or refinement, to that skill. Accordingly, the purpose of this review paper is to provide a comprehensive overview of current understanding pertaining to such practice. Specifically, this review addresses deliberately initiated refinements to closed and self-paced skills (e.g., javelin throwing, golf swing and horizontal jumps). In doing so, focus is directed to three fundamental considerations within applied coaching practice and future research endeavours; the intended outcomes, process and evaluative measures of skill refinement. Conclusions suggest that skill refinement is not the same as skill acquisition or performing already learnt skills with high-levels of automaticity. Due to the complexity of challenge faced, refinements are best addressed as an interdisciplinary solution, with objective measures informing coach decision making

A Virtual-Based Haptic Endoscopic Sinus Surgery (ESS) Training System: from Development to Validation

Simulated training platforms offer a suitable avenue for surgical students and professionals to build and improve upon their skills, without the hassle of traditional training methods. To enhance the degree of realistic interaction paradigms of training simulators, great work has been done to both model simulated anatomy in more realistic fashion, as well as providing appropriate haptic feedback to the trainee. As such, this chapter seeks to discuss the ongoing research being conducted on haptic feedback-incorporated simulators specifically for Endoscopic Sinus Surgery (ESS). This chapter offers a brief comparative analysis of some EES simulators, in addition to a deeper quantitative and qualitative look into our approach to designing and prototyping a complete virtual-based haptic EES training platform