Automated selection and entry of computed tomography data in finite element modelling of the human femur

Researchers in the Biomedical Engineering Centre (BEC) at Memorial University of Newfoundland are studying the structural and biomechanical properties of the human femur in order to better model and test hip prostheses. The advent of computed tomography (CT) technology has allowed researchers to visualize and use 3D anatomical data for such studies. In an attempt to generate realistic and useful 3D computer models of the human femur, BEC researchers have been using geometric and densimetric data from CT imagery to construct finite element models. Initial construction methods required manual input and manipulation of the data. This proved tedious and labour intensive. -- The aim of this project was to reduce user involvement and develop a software package to automate the model building process. By simplifying the procedure, it is hoped that users will be able to build models quickly and easily with minimal training in modelling software. Software modules were developed using several languages and run on a personal computer networked to a UNIX system. The software reads and translates CT data, detects and tracks the inner and outer edges of the femoral cortical bone, and selects equidistant points along these edges which define the geometry. This geometric data. combined with densimetric data in the form of CT numbers, is used to generate input files for the ANSYS finite element modelling package, which generates a solid volume model of the femur used for further testing. -- With restricted access to specimens and CT scanning facilities, testing of the software was limited throughout the course of this project. In view of the small test base, the results must be interpreted with caution, but preliminary results are encouraging. Compared with manual procedures used prior to this project, user involvement and the time needed to generate a model are dramatically reduced. The models are smoother in appearance and are easier to mesh. Direct measurement comparisons between true edges, and manually and automatically selected model edges indicate that the automated models are equal, if not superior, to those generated using the manual technique

Advanced Magnetic Resonance Imaging of Osteoarthritis

This thesis examines the potential utility of magnetic resonance (MR) quantitative imaging biomarkers (QIBs) of knee osteoarthritis (OA) for rapid assessment of treatment efficacy in experimental medicine studies. The development of treatments able to modify disease in OA is hampered by an inability to evaluate treatment response over a timeframe relevant to clinical trials. There are particular challenges in the experimental medicine setting due to the small numbers of participants and short follow-up duration relative to the expected time course of OA development and progression. Multiple MR QIBs of OA exist which may help address the problem of early evaluation of treatment response. However, their use in early phase studies has remained limited. Possible reasons for this include incomplete characterisation of the performance of QIBs in this setting and lack of head-to-head comparison of candidate QIBs to determine which would be optimal. This thesis aims to address these shortcomings and provide new information on the likely utility of MR QIBs in the setting of experimental medicine studies, as well as their potential for improving our general understanding of OA pathophysiology. I start by examining the reliability and ability to discriminate between OA and healthy knees of cartilage compositional MR imaging in a systematic review and meta-analysis. I then describe the development and validation of a novel semi-automatic surface-based method for analysing articular cartilage composition and morphology at the knee which may offer improved responsiveness and spatial localisation of change. Moving to QIBs of subchondral bone, I evaluate the association between measures of subchondral bone architecture derived from MR texture analysis and OA progression in the Osteoarthritis Initiative. The remainder of the thesis describes a prospective observational study where the utility of MR QIBs of synovium, subchondral bone and cartilage in experimental medicine studies is assessed. In summary, this thesis will inform decisions regarding the use of MR-based QIBs in future longitudinal and interventional studies. Their inclusion in experimental medicine studies may allow early assessment of treatment efficacy at a structural level and improve efficiency of treatment development pipelines.Funding: Addenbrooke's Charitable Trust, Experimental Medicine Initiative, non-investigator sponsored study grant from GlaxoSmithKlin

PRELIMINARY FINDINGS OF A POTENZIATED PIEZOSURGERGICAL DEVICE AT THE RABBIT SKULL

The number of available ultrasonic osteotomes has remarkably increased. In vitro and in vivo studies have revealed differences between conventional osteotomes, such as rotating or sawing devices, and ultrasound-supported osteotomes (Piezosurgery®) regarding the micromorphology and roughness values of osteotomized bone surfaces. Objective: the present study compares the micro-morphologies and roughness values of osteotomized bone surfaces after the application of rotating and sawing devices, Piezosurgery Medical® and Piezosurgery Medical New Generation Powerful Handpiece. Methods: Fresh, standard-sized bony samples were taken from a rabbit skull using the following osteotomes: rotating and sawing devices, Piezosurgery Medical® and a Piezosurgery Medical New Generation Powerful Handpiece. The required duration of time for each osteotomy was recorded. Micromorphologies and roughness values to characterize the bone surfaces following the different osteotomy methods were described. The prepared surfaces were examined via light microscopy, environmental surface electron microscopy (ESEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy. The selective cutting of mineralized tissues while preserving adjacent soft tissue (dura mater and nervous tissue) was studied. Bone necrosis of the osteotomy sites and the vitality of the osteocytes near the sectional plane were investigated, as well as the proportion of apoptosis or cell degeneration. Results and Conclusions: The potential positive effects on bone healing and reossification associated with different devices were evaluated and the comparative analysis among the different devices used was performed, in order to determine the best osteotomes to be employed during cranio-facial surgery

Preclinical MRI of the Kidney

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers

Preclinical MRI of the kidney : methods and protocols

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers