An Analysis by Synthesis Approach for Automatic Vertebral Shape Identification in Clinical QCT

Quantitative computed tomography (QCT) is a widely used tool for osteoporosis diagnosis and monitoring. The assessment of cortical markers like cortical bone mineral density (BMD) and thickness is a demanding task, mainly because of the limited spatial resolution of QCT. We propose a direct model based method to automatically identify the surface through the center of the cortex of human vertebra. We develop a statistical bone model and analyze its probability distribution after the imaging process. Using an as-rigid-as-possible deformation we find the cortical surface that maximizes the likelihood of our model given the input volume. Using the European Spine Phantom (ESP) and a high resolution \mu CT scan of a cadaveric vertebra, we show that the proposed method is able to accurately identify the real center of cortex ex-vivo. To demonstrate the in-vivo applicability of our method we use manually obtained surfaces for comparison.Comment: Presented on German Conference on Pattern Recognition (GCPR) 2018 in Stuttgar

Computed Tomography Osteodensitometry for Assessment of Bone Mineral Density of the Canine Head—Preliminary Results

Despite bone mineral density (BMD) being regularly measured in human patients, BMD studies in clinical cohorts of dogs is lacking. In order to facilitate BMD assessment and in turn better identify dogs suffering from metabolic bone disease, rapid, easy and precise computed tomography (qCT) techniques are required. In this study we aimed to assess the utility of quantitative computed tomography (qCT) bone mineral density (BMD) measurement of the canine calvarium using a semiautomated osteodensitometry software and define host factors associated with canine bone mineral density in a skeletally healthy population. Calvarial qCT at the level of the temporomandibular joints was performed on 323 dogs using a dedicated osteodensitometry calibration phantom during a clinically indicated head computed tomography (CT). Calvarial BMD was analyzed using a dedicated semiautomatic osteodensitometry software for contouring of the calvarial lamellar bone margins and BMD calculation. The mean duration of the calvarial qCT scanning was 64.6 s, and the mean duration of BMD analysis was 34 s, with a mean of two manual adjustments required for the bone margin tracing. The median BMD of all dogs in our study was 659 mg Calcium hydroxyapatite/mL. There was a negative linear correlation between BMD and body weight, but no correlation with age, sex or neutered status. Canine BMD assessment using qCT of the calvarium is a practical and fast technique that can be added to a clinical CT examination with minimal extra time requirements. Canine BMD host-dependent factors exhibit different relationships from that of humans; however, further investigation is warranted

Opportunistic diagnosis of osteoporosis, fragile bone strength and vertebral fractures from routine CT scans; a review of approved technology systems and pathways to implementation

Osteoporosis causes bones to become weak, porous and fracture more easily. While a vertebral fracture is the archetypal fracture of osteoporosis, it is also the most difficult to diagnose clinically. Patients often suffer further spine or other fractures, deformity, height loss and pain before diagnosis. There were an estimated 520,000 fragility fractures in the United Kingdom (UK) in 2017 (costing £4.5 billion), a figure set to increase 30% by 2030. One way to improve both vertebral fracture identification and the diagnosis of osteoporosis is to assess a patient’s spine or hips during routine computed tomography (CT) scans. Patients attend routine CT for diagnosis and monitoring of various medical conditions, but the skeleton can be overlooked as radiologists concentrate on the primary reason for scanning. More than half a million CT scans done each year in the National Health Service (NHS) could potentially be screened for osteoporosis (increasing 5% annually). If CT-based screening became embedded in practice, then the technique could have a positive clinical impact in the identification of fragility fracture and/or low bone density. Several companies have developed software methods to diagnose osteoporosis/fragile bone strength and/or identify vertebral fractures in CT datasets, using various methods that include image processing, computational modelling, artificial intelligence and biomechanical engineering concepts. Technology to evaluate Hounsfield units is used to calculate bone density, but not necessarily bone strength. In this rapid evidence review, we summarise the current literature underpinning approved technologies for opportunistic screening of routine CT images to identify fractures, bone density or strength information. We highlight how other new software technologies have become embedded in NHS clinical practice (having overcome barriers to implementation) and highlight how the novel osteoporosis technologies could follow suit. We define the key unanswered questions where further research is needed to enable the adoption of these technologies for maximal patient benefit

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

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

Investigation of Subchondral Bone Abnormalities associated with Osteoarthritis using Image-Based Biomechanics

Osteoarthritis (OA) is degenerative disease caused by a mechanical failure of bone and cartilage. Common risk factors for developing OA include: being over-weight, female, having joint malalignment, or a history of prior joint injury. Post-traumatic OA is extremely common in the knee as individuals frequently suffer injuries to structures that provide stability to the joint. To enhance our understanding about OA, animal models are employed where the injury can be and monitored in a controlled environment. When used in conjunction with pre-clinical imaging techniques the longitudinal degradation of bone and cartilage can be quantitatively monitored in vivo. Recent evidence has identified cystic lesions within the subchondral bone as the possible source of painful symptoms and accelerated disease progression, but little is known about their etiology. The purpose of this thesis was to improve knowledge regarding the mechanism that causes subchondral cysts. OA was induced in the rodent knee via surgery, and the pathological changes were quantified with micro-CT and MRI. The composition of the cysts was correlated with end-stage histology. Thus, an accurate definition of OA bone cysts was achieved. To assess the effect of cysts in human bone, a study was conducted using a patient data set restrospectively. Using finite element (FE) analysis, higher stress values were found within bone surrounding cysts. Therefore, the probable mechanism of cyst expansion, stress induced resorption, was identified. Finally, the FE models of the bones were combined with soft tissue structures – from a co-registered MRI – to produce comprehensive patient-specific models of the knee

Quantification of bone using a 3.0 tesla clinical magnetic resonance scanner

The work in this thesis examines the potential of using magnetic resonance imaging and spectroscopy (MRI & MRS) as a quantitative tool for diagnosing bone abnormalities at multiple skeletal sites, which could be used in conjunction with routine clinical imaging.MRI and MRS are routinely used in the clinical setting for the diagnosis of various types of diseases and abnormalities due to its advantages of providing excellent soft tissue contrast and also providing physiological and metabolic information. The use of MRI and MRS as a direct diagnostic tool for bone abnormalities is very limited at the moment due to issues of costs and standardisation. The aim in this thesis was to use the clinical 3.0 T MR scanner to acquire data from bone and bone marrow for identification of structural and chemical properties and to use those features to identify differences in bone strength and condition. The volunteers in this thesis were part of the high bone mass (HBM) study and they had additional acquisitions from dual-energy X-ray absorptiometry (DEXA) and peripheral quantitative computed tomography (pQCT).MR acquisition protocols have been successfully optimised for each type of bone region and in-house software has also been created to process the acquired data and quantify various types of structural and chemical properties.The MR data from distal radius and tibia demonstrated good correlation with pQCT data (e.g. Figure 8-2 & Figure 8-3) and were also able to differentiate between HBM-affected and control populations (e.g. Figure 8-26). The MR data from lumbar vertebrae also demonstrated good correlation with DEXA data and some of the measurements were also able to differentiate between the HBM-affected and control populations.The combined results from this thesis demonstrate that both MRI and MRS are sensitive techniques for measurement of bone quantity and quality, and they are ready to be applied for clinical investigation as part of routine clinical imaging to identify bone strength in relation to abnormalities and treatments

Risk Assessment and Interventions for Individuals at Risk of Osteoporotic Fractures

Older adults, especially with low bone mass, hyperkyphosis or vertebral fractures (OVF), and individual with spinal cord injury (SCI) are at increased risk of fragility fractures. Individuals with SCI and OVFs are subgroups of people with osteoporosis that are at high risk of fractures and present unique impairments, limitations, and restrictions that require population-specific and individually tailored and interventions. The objectives of this thesis were: 1) to explore potential sources of error during LS bone densitometry and trabecular bone score (TBS) values in individuals with SCI, and the applicability of TBS in fracture risk assessment; 2) to assess the effects of PRT on health-related outcomes in people with low bone mass or hyperkyphosis; 3) to establish recommendations for the non-pharmacological management of osteoporotic vertebral fractures; 4) to co-develop a virtually delivered education and training program on safe movement, pain management, nutrition, and exercise among people with osteoporotic vertebral fractures, and to test its acceptability and usability. Chapter one consists of a review of the literature on the epidemiology of fragility fractures, their consequences in the populations at greater risk, and the knowledge gaps in terms of risk assessment and non-pharmacological management. Chapter two presents the findings from two observational studies. Study 1 explored potential sources of error during LS densitometry in people with chronic SCI. Facet sclerosis and osteophytes and challenges in detecting bone edges are the most common sources of error, and most of the scans presented vertebrae with outlier BMD values. Study 2 described lumbar spine TBS values in a cohort of people with chronic SCI, whether they change over a two-year period, and how TBS affects fracture risk assessment in people with SCI. Individuals with chronic SCI on this cohort presented with normal bone microarchitecture based on TBS. TBS was not different between sexes, people with motor complete and motor incomplete injury or with and without previous fragility fracture. Clinical decisions regarding fracture prevention should not be based on TBS or FRAX® in people with chronic SCI at this time. The third chapter reports the protocols of two systematic reviews. One systematic review investigated the effects of PRT interventions on health-related outcomes in people with low bone mass, while the second investigated the effects of exercise interventions on improving postural and health-related outcomes in people with hyperkyphosis. The fourth chapter reports the outcomes of an International Modified Delphi Consensus process, which established recommendations on the non-pharmacological management of osteoporotic vertebral fractures. We generated recommendations on pain management (e.g., educate on pain expectation; assess pain-related psychological factors; limit prolonged sitting; lying supine with feet flat on surface and knees bent), nutrition (e.g., educating on recommended daily intake of protein, calcium, and vitamin D; refer to dietitian in presence of poor appetite or weight loss), safe movement (e.g., avoid heavy physical exertion, lifting, or activities that exacerbate pain for the first 12 weeks; bend at hip and knees; step to turn; hold objects close to body), and exercise (e.g., timing, intensity, example exercises, goals including improving back extensor endurance, spinal mobility, physical functioning, and balance). There was consensus on limiting bed rest, and on prescribing orthoses only to select patients. The fifth chapter presents the co-development of a virtual intervention for the non-pharmacological management of OVF (VIVA) and its acceptability and usability testing among people with OVF. VIVA has been co-developed to provide education and training on safe movement and pain management techniques, nutrition, and exercise, and involves seven 1-on-1 virtual sessions delivered by a physiotherapist over five weeks. We delivered VIVA to 8 individuals with vertebral fractures, to evaluate acceptability and usability. Participants perceived improvements in pain and felt more confident during the activities of daily living and in self-managing their OVF. All the participants believed that VIVA was very useful and were very satisfied with the 1-on-1 sessions. Three participants found the information received very easy to practice, four participants believed they were easy to practice, and one participant found them somewhat difficult. Four participants were very satisfied and four were satisfied with the supporting resources delivered throughout the program. Participants found accessing the resources easy, but think that logging in and out to access videos and resources, or to track adherence, was cumbersome. Chapter six provides a general discussion of how the present dissertation improved the knowledge in fracture risk assessment and non-pharmacological interventions in people at risk of fractures, and what the next steps to address the knowledge-to-action gaps in populations at high risk of fracture should be