Bone health assessment via digital wrist tomosynthesis in the mammography setting

Bone fractures attributable to osteoporosis are a significant problem. Though preventative treatment options are available for individuals who are at risk of a fracture, a substantial number of these individuals are not identified due to lack of adherence to bone screening recommendations. The issue is further complicated as standard diagnosis of osteoporosis is based on bone mineral density (BMD) derived from dual energy x-ray absorptiometry (DXA), which, while helpful in identifying many at risk, is limited in fully predicting risk of fracture. It is reasonable to expect that bone screening would become more prevalent and efficacious if offered in coordination with digital breast tomosynthesis (DBT) exams, provided that osteoporosis can be assessed using a DBT modality. Therefore, the objective of the current study was to explore the feasibility of using digital tomosynthesis imaging in a mammography setting. To this end, we measured density, cortical thickness and microstructural properties of the wrist bone, correlated these to reference measurements from microcomputed tomography and DXA, demonstrated the application in vivo in a small group of participants, and determined the repeatability of the measurements. We found that measurements from digital wrist tomosynthesis (DWT) imaging with a DBT scanner were highly repeatable ex vivo (error = 0.05%-9.62%) and in vivo (error = 0.06%-10.2%). In ex vivo trials, DWT derived BMDs were strongly correlated with reference measurements (R = 0.841-0.980), as were cortical thickness measured at lateral and medial cortices (R = 0.991 and R = 0.959, respectively) and the majority of microstructural measures (R = 0.736-0.991). The measurements were quick and tolerated by human patients with no discomfort, and appeared to be different between young and old participants in a preliminary comparison. In conclusion, DWT is feasible in a mammography setting, and informative on bone mass, cortical thickness, and microstructural qualities that are known to deteriorate in osteoporosis. To our knowledge, this study represents the first application of DBT for imaging bone. Future clinical studies are needed to further establish the efficacy for diagnosing osteoporosis and predicting risk of fragility fracture using DWT

Non-destructive quality control of carbon anodes using modal analysis, acousto-ultrasonic and latent variable methods

La performance des cuves d’électrolyse utilisées dans la production d’aluminium primaire par le procédé Hall-Héroult est fortement influencée par la qualité des anodes de carbone. Celles-ci sont de plus en plus variables en raison de la qualité décroissante des matières premières (coke et braie) et des changements de fournisseurs qui deviennent de plus en plus fréquents afin de réduire le coût d’achat et de rencontrer les spécifications des usines. En effet, les défauts des anodes, tels les fissures, les pores et les hétérogénéités, causés par cette variabilité, doivent être détectés le plus tôt possible afin d’éviter d’utiliser des anodes défectueuses dans les cuves et/ou d’apporter des ajustements au niveau du procédé de fabrication des anodes. Cependant, les fabricants d’anodes ne sont pas préparés pour réagir à cette situation afin de maintenir une qualité d'anode stable. Par conséquent, il devient prioritaire de développer des techniques permettant d’inspecter le volume complet de chaque anode individuelle afin d’améliorer le contrôle de la qualité des anodes et de compenser la variabilité provenant des matières premières. Un système d’inspection basé sur les techniques d’analyse modale et d’acousto-ultrasonique est proposé pour contrôler la qualité des anodes de manière rapide et non destructive. Les données massives (modes de vibration et signaux acoustiques) ont été analysées à l'aide de méthodes statistiques à variables latentes, telles que l'Analyse en Composantes Principales (ACP) et la Projection sur les Structures Latentes (PSL), afin de regrouper les anodes testées en fonction de leurs signatures vibratoires et acousto-ultrasoniques. Le système d'inspection a été premièrement investigué sur des tranches d'anodes industrielles et ensuite testé sur plusieurs anodes pleine grandeur produites sous différentes conditions à l’usine de Alcoa Deschambault au Québec (ADQ). La méthode proposée a permis de distinguer les anodes saines de celles contenant des défauts ainsi que d’identifier le type et la sévérité des défauts, et de les localiser. La méthode acousto-ultrasonique a été validée qualitativement par la tomographie à rayon-X, pour les analyses des tranches d’anodes. Pour les tests réalisés sur les blocs d’anode, la validation a été réalisée au moyen de photos recueillies après avoir coupé certaines anodes parmi celles testées.The performance of the Hall-Héroult electrolysis reduction process used for the industrial aluminium smelting is strongly influenced by the quality of carbon anodes, particularly by the presence of defects in their internal structure, such as cracks, pores and heterogeneities. This is partly due to the decreasing quality and increasing variability of the raw materials available on the market as well as the frequent suppliers changes made in order to meet the smelter’s specifications and to reduce purchasing costs. However, the anode producers are not prepared to cope with these variations and in order to maintain consistent anode quality. Consequently, it becomes a priority to develop alternative methods for inspecting each anode block to improve quality control and maintain consistent anode quality in spite of the variability of incoming raw materials.A rapid and non-destructive inspection system for anode quality control is proposed based on modal analysis and acousto-ultrasonic techniques. The large set of vibration and acousto-ultrasonic data collected from baked anode materials was analyzed using multivariate latent variable methods, such as Principal Component Analysis (PCA) and Partial Least Squares (PLS), in order to cluster the tested anodes based on vibration and their acousto-ultrasonic signatures. The inspection system was investigated first using slices collected from industrial anodes and then on several full size anodes produced under different conditions at the Alcoa Deschambault in Québec (ADQ). It is shown that the proposed method allows discriminating defect-free anodes from those containing various types of defects. In addition, the acousto-ultrasonic features obtained in different frequency ranges were found to be sensitive to the defects severities and were able to locate them in anode blocks. The acousto-ultrasonic method was validated qualitatively using X-ray computed tomography, when studying the anode slices. The results obtained on the full size anode blocks were validated by means of images collected after cutting some tested anodes

Detection of osteoporosis in lumbar spine [L1-L4] trabecular bone: a review article

The human bones are categorized based on elemental micro architecture and porosity. The porosity of the inner trabecular bone is high that is 40-95% and the nature of the bone is soft and spongy where as the cortical bone is harder and is less porous that is 5 to 15%. Osteoporosis is a disease that normally affects women usually after their menopause. It largely causes mild bone fractures and further stages lead to the demise of an individual. This analysis is on the basis of bone mineral density (BMD) standards obtained through a variety of scientific methods experimented from different skeletal regions. The detection of osteoporosis in lumbar spine has been widely recognized as a promising way to frequent fractures. Therefore, premature analysis of osteoporosis will estimate the risk of the bone fracture which prevents life threats. This paper focuses on the advanced technology in imaging systems and fracture probability analysis of osteoporosis detection. The various segmentation techniques are explored to examine osteoporosis in particular region of the image and further significant attributes are extracted using different methods to classify normal and abnormal (osteoporotic) bones. The limitations of the reviewed papers are more in feature dimensions, lesser accuracy and expensive imaging modalities like computed tomography (CT), magnetic resonance imaging (MRI), and DEXA. To overcome these limitations it is suggested to have less feature dimensions, more accuracy and cost-effective imaging modality like X-ray. This is required to avoid bone fractures and to improve BMD with precision which further helps in the diagnosis of osteoporosis

Image analysis for extracapsular hip fracture surgery

PhD ThesisDuring the implant insertion phase of extracapsular hip fracture surgery, a surgeon visually inspects digital radiographs to infer the best position for the implant. The inference is made by “eye-balling”. This clearly leaves room for trial and error which is not ideal for the patient. This thesis presents an image analysis approach to estimating the ideal positioning for the implant using a variant of the deformable templates model known as the Constrained Local Model (CLM). The Model is a synthesis of shape and local appearance models learned from a set of annotated landmarks and their corresponding local patches extracted from digital femur x-rays. The CLM in this work highlights both Principal Component Analysis (PCA) and Probabilistic PCA as regularisation components; the PPCA variant being a novel adaptation of the CLM framework that accounts for landmark annotation error which the PCA version does not account for. Our CLM implementation is used to articulate 2 clinical metrics namely: the Tip-Apex Distance and Parker’s Ratio (routinely used by clinicians to assess the positioning of the surgical implant during hip fracture surgery) within the image analysis framework. With our model, we were able to automatically localise signi cant landmarks on the femur, which were subsequently used to measure Parker’s Ratio directly from digital radiographs and determine an optimal placement for the surgical implant in 87% of the instances; thereby, achieving fully automatic measurement of Parker’s Ratio as opposed to manual measurements currently performed in the surgical theatre during hip fracture surgery

Trabecular Bone Microarchitecture in Association with Systemic and Local Factors as Potential Predictors of Implant Failure

Clinicians have described the success rates of dental implants. The use of implants is projected to increase in the future. With a 5-10% failure rate, it is unclear the exact factors that are associated with implant failures. To improve upon these success rates, it is critical to understand parameters associated with implant failure including: periodontitis, peri-implantitis, systemic diseases, site preparation, dental history of the implant site, bone quality, materials, occlusion, and treatment timelines. While bone quality is associated with failure, objective measures to assess bone quality and characteristics are scarce. Therefore, the aim of this study is to determine whether possible comorbidities, associated dental parameters, and measurable bone quality are possible predictors of implant failure. In this study, we utilized the electronic health record system axiUm® to retrospectively investigate non-failed (NF) and failed (F) dental implants from a patient cohort with 149 implants placed between 2012-2015 at Virginia Commonwealth University School of Dentistry. A chart review was conducted extracting information on age, gender, systemic diseases, smoking, occlusal trauma, parafunction, bone grafting history, treatment timelines, implant site/type/placement protocol, infection, torque at placement, bone quality and microarchitecture assessed by the novel, innovative technology: trabecular bone score (TBS). A total of 149 implants, 46 failures and 105 non-failed controls, were selected based on similar implant sites. Preliminary data obtained from analysis suggests that average time from implant placement to failure was 6.6 months (0.55 years). Parafunction habit (p=0.0202) and increased number of implants (p=0.0478) were found to be associated with increased implant failure

Quantitative imaging techniques for the assessment of osteoporosis and sarcopenia

Bone and muscle are two deeply interconnected organs and a strong relationship between them exists in their development and maintenance. The peak of both bone and muscle mass is achieved in early adulthood, followed by a progressive decline after the age of 40. The increase in life expectancy in developed countries resulted in an increase of degenerative diseases affecting the musculoskeletal system. Osteoporosis and sarcopenia represent a major cause of morbidity and mortality in the elderly population and are associated with a significant increase in healthcare costs. Several imaging techniques are currently available for the non-invasive investigation of bone and muscle mass and quality. Conventional radiology, dual energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound often play a complementary role in the study of osteoporosis and sarcopenia, depicting different aspects of the same pathology. This paper presents the different imaging modalities currently used for the investigation of bone and muscle mass and quality in osteoporosis and sarcopenia with special emphasis on the clinical applications and limitations of each technique and with the intent to provide interesting insights into recent advances in the field of conventional imaging, novel high-resolution techniques and fracture risk

Mesoporous bioactive glasses as smart platform to stimulate bone regeneration

L'abstract è presente nell'allegato / the abstract is in the attachmen

Intrinsic osteoinduction and osteogenesis of biomimetic calcium phosphate scaffolds with different nano-, micro- and macroporosities : ectopic and orthotopic implantation in a canine model

The development of synthetic bone substitutes with enhanced osteogenic properties is urged by the global ageing population. Sintered calcium-phosphate (CaP) ceramics are the most widely used synthetic biomaterials for bone regeneration. However, their clinical performance is inferior to those of autografts, which are still considered the gold standard, despite the serious drawbacks associated with the need of a harvesting surgery. This thesis aims at providing new insights in the development of CaP biomaterials with osteoinductive properties, this is, with the capacity to foster the differentiation of mesenchymal stem cells to bone forming cells, without the need of adding exogenous growth factors. Previous studies pointed to chemical composition, macropore architecture, microstructural topography and specific surface area (SSA) as critical factors in the intrinsic osteoinduction of biomaterials. However, only sintered ceramics with a limited range of porosities and low SSAs had been analyzed so far. In the present thesis, we were able to extend this range to the nanoscale by using biomimetic low-temperature processing routes. Foaming and 3D-printing methods allowed producing biomimetic CaP scaffolds with tailored macropore architectures together with controlled micro and nanoporosity and, hence, high SSAs. In order to evaluate the intrinsic osteoinduction of this new family of biomimetic bone substitutes, nanostructured calcium deficient hydroxyapatite (CDHA) scaffolds with needle-like crystal morphology were implanted intramuscularly in a canine model, and compared with two sintered ceramics, namely biphasic calcium phosphate and beta-tricalcium phosphate (Study I). The results showed that the high reactivity of nanostructured biomimetic CDHA, combined with a spherical concave macroporosity of foamed scaffolds, accelerated and enhanced the osteoinduction potential beyond the limits of conventional, microstructured, sintered ceramics. As a second step, the effect of macropore geometry of nanostructured CDHA on the bone healing capacity was analyzed. The same foamed and 3D-printed CDHA scaffolds were implanted intraosseoulsy in a canine model (Study II). Whereas nanostructured CDHA was shown to be highly osteoconductive irrespective of macropore geometry, a superior osteogenic capacity was observed in the foamed scaffolds, which correlated well with the higher intrinsic osteoinductive potential demonstrated previously. Moreover, foams showed a higher cell-mediated degradation than the 3D-printed constructs, with a simultaneous and progressive replacement of the scaffold by new bone, demonstrating that the control of macropore architecture allows tuning both material degradation and new bone formation. Finally, aiming to further mimic the natural bone apatite, the effect of nanocrystal morphology (plate vs. needle) and carbonate doping on the intrinsic bioactivity of biomimetic CDHA was investigated. To this end, CDHA foams with different nanostructures (Coarse/Fine-CDHA) and carbonated CDHA foams were compared, both in canine ectopic and orthotopic implantation models (Study III). Fine-CDHA foams showed a superior osteoinduction and bone healing potential, as well as a higher degradation than Coarse-CDHA foams, suggesting that there is a threshold value in terms of SSA necessary to activate the cell-mediated resorption and the associated osteoinduction, which determines in turn the osteogenic capacity of the materials in a bony enviroment. Moreover, carbonate dopping of CDHA accelerated both intrinsic osteoinduction and bone healing, simultaneously increasing the cell-mediated resorption. Thus, the increased biomimetism of CDHA allowed the material to enter the natural bone remodelling cycle, this resulting in a tight synchronization between material degradation and bone formation, and ultimately, obtaining bone substitutes with enhanced bone regeneration potential.L’envelliment global de la població exigeix el desenvolupament de nous substituts ossis sintètics amb capacitats osteogèniques optimitzades. Tot i que les ceràmiques de fosfats de calci (CaP) sinteritzades són els biomaterials sintètics més utilitzats en regeneració òssia, la seva eficiència és inferior a la dels empelts d’ós autòleg, els quals continuen sent el tractament de primera elecció malgrat presentar inconvenients importants associats a la necessitat d’una segona cirurgia. Aquesta tesi té com a objectiu optimitzar el desenvolupament de biomaterials de CaP amb propietats osteoinductives, fet que estimula la diferenciació de cèl·lules mare mesenquimals a cèl·lules osteogèniques, sense l’ús de factors de creixement exògens. Estudis recents han identificat diferents factors crítics en l’osteoinducció intrínseca dels biomaterials com ara la composició química, la macroporositat, la microestructura i la superfície específica (SSA). Fins al moment, només s’han analitzat ceràmiques sinteritzades amb un rang limitat de porositats i SSAs. Tanmateix, en la present tesi s’ha aconseguit augmentar aquest rang a la nanoescala per mitjà de rutes de processament biomimètiques a baixes temperatures. L’escumat i la impressió 3D de CaP biomimètics, ha permès l’obtenció d’implants amb arquitectures macroporoses específicament modulades conjuntament amb micro i nanoporositats controlades, i per tant, amb SSAs significativament superiors. Per tal d'avaluar l'osteoinducció intrínseca d'aquests nous materials biomimètics, es van implantar intramuscularment materials nanoestructurats (cristalls tipus agulla) de hidroxiapatita deficient en calci (CDHA) en un model caní, i es van comparar amb dues ceràmiques sinteritzades (Estudi I). Els resultats van mostrar que la gran reactivitat de la CDHA nanoestructurada, combinada amb una macroporositat esfèrica còncava de les escumes, van incrementar el potencial d'osteoinducció més enllà dels límits oferts per les ceràmiques sinteritzades microestructurades. El segon pas va consistir en l’anàlisi de l'efecte de la geometria de la macroporositat dels materials de CDHA sobre la seva capacitat de consolidació òssia, implantant els materials escumats i els impresos en 3D a nivell intraossi en un model caní (Estudi II). Tot i que la CDHA nanoestructurada va demostrar ser altament osteoconductiva independentment de la geometria macroporosa, les escumes van mostrar una capacitat osteogènica superior, correlacionant-se directament amb el major potencial osteoinductiu intrínsec demostrat anteriorment. A més, les escumes van mostrar una reabsorció cel·lular superior als implants obtinguts per impressió 3D, substituint progressivament el material per nou os i, demostrant així que el control de l'arquitectura de la macroporositat permet adequar tant la degradació del material com fomentar la regeneració òssia. Finalment, amb l'objectiu de mimetitzar encara més la fase mineral òssia, es va investigar l’efecte de la morfologia dels nanocristalls (placa vs. agulla) i del dopatge amb ions carbonat sobre la bioactivitat intrínseca de la CDHA biomimètica, implantant escumes de CDHA amb diferents nanoestructures (Coarse/Fine-CDHA) i escumes carbonatades a nivell ectòpic i ortotòpic en gos (Estudi III). Les escumes Fine-CDHA van mostrar un potencial osteoinductiu i osteogènic superiors, i una degradació incrementada respecte a les escumes Coarse-CDHA, suggerint que existeix una SSA mínima per activar la degradació cel·lular dels materials i la conseqüent resposta osteoinductiva, fet que determina la capacitat osteogènica dels materials en un defecte ossi. La carbonatació de la CDHA va accelerar tant el potencial osteoinductiu i osteogènic, com la degradació cel·lular dels materials, suggerint que l’increment del biomimetisme de la CDHA afavoreix la introducció del material dins del cicle de remodelació òssi

Texture analysis and Its applications in biomedical imaging: a survey

Texture analysis describes a variety of image analysis techniques that quantify the variation in intensity and pattern. This paper provides an overview of several texture analysis approaches addressing the rationale supporting them, their advantages, drawbacks, and applications. This survey’s emphasis is in collecting and categorising over five decades of active research on texture analysis.Brief descriptions of different approaches are presented along with application examples. From a broad range of texture analysis applications, this survey’s final focus is on biomedical image analysis. An up-to-date list of biological tissues and organs in which disorders produce texture changes that may be used to spot disease onset and progression is provided. Finally, the role of texture analysis methods as biomarkers of disease is summarised.Manuscript received February 3, 2021; revised June 23, 2021; accepted September 21, 2021. Date of publication September 27, 2021; date of current version January 24, 2022. This work was supported in part by the Portuguese Foundation for Science and Technology (FCT) under Grants PTDC/EMD-EMD/28039/2017, UIDB/04950/2020, PestUID/NEU/04539/2019, and CENTRO-01-0145-FEDER-000016 and by FEDER-COMPETE under Grant POCI-01-0145-FEDER-028039. (Corresponding author: Rui Bernardes.)info:eu-repo/semantics/publishedVersio