928 research outputs found

    Predictive Modelling of Bone Age through Classification and Regression of Bone Shapes

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    Bone age assessment is a task performed daily in hospitals worldwide. This involves a clinician estimating the age of a patient from a radiograph of the non-dominant hand. Our approach to automated bone age assessment is to modularise the algorithm into the following three stages: segment and verify hand outline; segment and verify bones; use the bone outlines to construct models of age. In this paper we address the final question: given outlines of bones, can we learn how to predict the bone age of the patient? We examine two alternative approaches. Firstly, we attempt to train classifiers on individual bones to predict the bone stage categories commonly used in bone ageing. Secondly, we construct regression models to directly predict patient age. We demonstrate that models built on summary features of the bone outline perform better than those built using the one dimensional representation of the outline, and also do at least as well as other automated systems. We show that models constructed on just three bones are as accurate at predicting age as expert human assessors using the standard technique. We also demonstrate the utility of the model by quantifying the importance of ethnicity and sex on age development. Our conclusion is that the feature based system of separating the image processing from the age modelling is the best approach for automated bone ageing, since it offers flexibility and transparency and produces accurate estimate

    Predictive Modelling of Bone Ageing

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    Bone age assessment (BAA) is a task performed daily by paediatricians in hospitalsworldwide. The main reasons for BAA to be performed are: fi�rstly, diagnosis of growth disorders through monitoring skeletal development; secondly, prediction of final adult height; and fi�nally, verifi�cation of age claims. Manually predicting bone age from radiographs is a di�fficult and time consuming task. This thesis investigates bone age assessment and why automating the process will help. A review of previous automated bone age assessment systems is undertaken and we investigate why none of these systems have gained widespread acceptance. We propose a new automated method for bone age assessment, ASMA (Automated Skeletal Maturity Assessment). The basic premise of the approach is to automatically extract descriptive shape features that capture the human expertise in forming bone age estimates. The algorithm consists of the following six modularised stages: hand segmentation; hand segmentation classifi�cation; bone segmentation; feature extraction; bone segmentation classifi�cation; bone age prediction. We demonstrate that ASMA performs at least as well as other automated systems and that models constructed on just three bones are as accurate at predicting age as expert human assessors using the standard technique. We also investigate the importance of ethnicity and gender in skeletal development. Our conclusion is that the feature based system of separating the image processing from the age modelling is the best approach, since it off�ers flexibility and transparency, and produces accurate estimates

    Skeletal growth estimation using radiographic image processing and analysis

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    Developmental Genetics and Preimplantation Genetic Diagnosis

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    The genetic code information programs the embryogenesis. In this chapter the three phases of prenatal development the pre-embryonic, the embryonic and the fetal are elaborated. The role played by transforming growth factor beta related genes in the growth and differentiation of early embryo will be described. The implications of Fibroblast growth factor gene in binding heparin its effect on cell survival and mitogenic pathways is discussed. The orchestrated symphony of Sonic Hedgehog genes in early human embryo development is elaborated. The Homeobox genes (Hox gene) and their role in early human embryogenesis are described. The different tests available for prenatal genetic testing are briefly described. Preimplantation genetic diagnostic procedures are indispensable in clinical embryology. The microsurgical techniques of the Polar body biopsy, Blastomere biopsy and Blastocyst biopsy are discussed at the end of the chapter. A diagrammatic representation of individuals and relationships in clinical genetics is described. A brief description of procedures of invasive fetal tests for collecting the fetal tissue is also discussed

    The role of forensic dentist following mass disaster

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    This review article focuses on mass disaster situations that may arise from natural or manmade circumstances and the significant role of forensic dental personnel in human identification following such occurrences. The various forensic dental modalities of identification that include matching techniques, postmortem profiling, genetic fingerprinting, dental fossil assessment and dental biometrics with digital subtraction were considered. The varying extent of use of forensic dental techniques and the resulting positive impact on human identification were considered. The importance of preparation by way of special training for forensic dental personnel, mock disaster rehearsal, and use of modern day technology was stressed. The need for international standardization of identification through the use of Interpol Disaster Victim Identification (DVI) for ms was further emphasized. Recommendations for improved human identification in Nigerian situation include reform of the National Emergency Management Association (NEMA), incorporation of dental care in primary health care to facilitate proper ante mortem database of the populace and commencement of identification at site of disaster

    Development of a Three-Dimensional Anthropometric Model for Simulating Hand Work

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    This dissertation aims to increasing the understanding on the variables needed to realistically model a human hand by 1) developing a skeleton-driven 3-D parametric model of the hand, and 2) providing new data for predicting hand strength capabilities. Hand models can be used to understand the effect of hand posture and shape to force exertions while interacting with surfaces. 3D models representing skin and bone surfaces and their axes for use in simulation models were developed from Hand-CT Scans. These models were used to adapt four methods for determining phalange Centers of Rotation (CoR). Sphere- and Ellipsoid-fitted CoRs were considered fixed, with pin-joint rotational axes and simple links. 3D-Reuleaux and ICP-based CoRs were considered instantaneous, with variable link lengths affected by the rotation and gliding of the adjacent anatomical segments. There was a significant difference between fixed and instantaneous CoRs, leading to a more accurate and robust kinematic model. These CoRs were leveraged to develop landmark-free statistical models from 43 clinical hand-CT scans. The 3D-surfaces of flat hand posture, previously developed, were used to standardize the data. Kinematics developed from the ICP method were used to rotate finger segments of fitted hands to 1) obtain hand skin measurements in a common posture, 2) predict whole hand skeleton shape/size, and 3) evaluate final shape predictions in their original postures. Principal component analysis and regression (PCAR) were used to develop statistical models for shape/size prediction of individual finger bone geometries, as well as a whole hand skeleton model with hand skin surface reference points for scaling based on anthropometric data (hand length, hand breadth, hand thickness and sex). The predicted skeleton with the skin reference points can be used as a baseline for any hand surface model to establish kinematics based on internal bone segments. Additionally, to complement data in literature, a study of 12 participants was performed to investigate the effect of hand posture and surface orientation on hand force while pressing a flat surface. Joint moment and finger force distribution data from this study can be incorporated in computerized 3D-models of the hand to compare strength capabilities between postures.PHDIndustrial & Operations EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138612/1/rosemfig_1.pd

    Comparison of extraction sites versus artificial defects with xenogenic bone substitute in minipigs

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    Objectives The preclinical evaluation of bone substitutes is frequently performed in artificially created defects. However, such defects do not reflect the predominant clinical application of bone substitutes for socket preservation. Hence, the goal of this animal study was to compare the performance of a xenogenic bone substitute in extraction sites versus artificial defects. Material and Methods Four study sites each were created in the mandibles of four minipigs in the region of the third premolars and first molars, respectively. On one side, fresh extraction sockets were established while contralaterally trephine defects were created in healed alveolar bone. All sites were augmented using a particulate xenogenic bone substitute, covered by resorbable membranes and allowed to heal for 12 weeks. The amounts of new bone, non-bone tissue and remaining bone substitute granules were quantified through histological and micro-CT analysis. Comparative statistics were based on t-tests for two samples and ANOVA with the level of significance set at α = 0.05. Results Histomorphometric data from only two animals could be quantitatively analyzed due to difficulty with identifying the surgical sites. The percentage of newly formed bone ranged between 53.2% ± 5.6% for artificial defects and 54.9% ± 12.4% for extraction sites. With the exception of ANOVA indicating a greater amount of non-bone tissue in extraction sites as compared to artificial sites (p = 0.047), no statistically significant differences were observed. Micro-CT scans showed patterns similar to the ones observed in histomorphometry. As extraction sites could be identified only in two micro-CT reconstructions, quantitative assessment was not undertaken. Conclusions Despite the comparable performance of bone substitute material in artificial defects and extraction sites found here, the data gathered with this experiment was insufficient for showing equivalence of both approaches

    Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

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    In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

    Osteocytes Influence on Bone Matrix Integrity Affects Biomechanical Competence at Bone-Implant Interface of Bioactive-Coated Titanium Implants in Rat Tibiae

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    Osseointegration is a prerequisite for the long-term success of implants. Titanium implants are preferred for their biocompatibility and mechanical properties. Nonetheless, the need for early and immediate loading requires enhancing these properties by adding bioactive coatings. In this preclinical study, extracellular matrix properties and cellular balance at the implant/bone interface was examined. Polyelectrolyte multilayers of chitosan and gelatin or with chitosan and Hyaluronic acid fabricated on titanium alloy using a layer-by-layer self-assembly process were compared with native titanium alloy. The study aimed to histologically evaluate bone parameters that correlate to the biomechanical anchorage enhancement resulted from bioactive coatings of titanium implants in a rat animal model. Superior collagen fiber arrangements and an increased number of active osteocytes reflected a significant improvement of bone matrix quality at the bone interface of the chitosan/gelatin-coated titan implants over chitosan/hyaluronic acid-coated and native implants. Furthermore, the numbers and localization of osteoblasts and osteoclasts in the reparative and remodeling phases suggested a better cellular balance in the chitosan/Gel-coated group over the other two groups. Investigating the micro-mechanical properties of bone tissue at the interface can elucidate detailed discrepancies between different promising bioactive coatings of titanium alloys to maximize their benefit in future medical applications
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