DIGITAL IMAGE PROCESSING FOR ULTRASONIC THERAPY AND TENDINOUS INJURY

In this master\u27s thesis, several digital image processing techniques are explored for potential in evaluation of Brightness mode (B-mode) ultrasound images. Currently, many processing techniques are utilized during ultrasound visualization in cardiovascular applications, mammography, and three-dimensional ultrasound systems. However, approaches that serve to aid the clinician in diagnostic assessment of tendinous and ligamentous injuries are more limited. Consequently, the methods employed below are aimed at reducing the dependence on clinician judgment alone to assess the healing stage and mechanical properties of tendinous injuries. Initial focus concentrated on the use of entropy in texture analysis to relate a tendon\u27s appearance in an ultrasound image to its mechanical integrity. Confounding effects such as motion artifacts and region of interest selection by the user limited the applicability of small regions selected for analysis, but general trends were observed when the entire visualized tendon or superficial background region was selected. Entropy calculations suggested a significant change in texture pattern for tendinous regions compared to the selected background regions. In order to reduce the impact of motion artifacts and dependence of the texture analysis on manual identification of regions of interest, a Matlab® script was developed intended to isolate the tendinous regions of interest for further analysis. Methods for segmentation employed relied on a moving window Fourier Transform to compare local parameters in the image to a predefined window of tendinous tissue. Further assessment of each local region benefited from parameterization of the local window\u27s properties that focused on capturing indicators of mean pixel intensity, local variation in pixel intensity, and local directionality consistency derived from the spatial frequency patterns observed in the Fourier Transforms via comparison by the circular Earth Mover\u27s Distance. Results of the segmentation algorithm developed indicated the presence of directional consistency within the tendinous regions, and changes in the speckle pattern were observed for the image derived from mean intensity and local pixel intensity variation. However, non-tendinous regions were also identified for their directional consistency, limiting the applicability of the current process in tendinous region isolation. The results obtained for calculations of the circular Earth Mover\u27s Distance improved slightly with the inclusion of temporal averaging and image registration, but still require improvement before implementation in clinical applications can be realized

Texture Analysis of Supraspinatus Ultrasound Image for Computer Aided Diagnostic System

OBJECTIVES: In this paper, we proposed an algorithm for recognizing a rotator cuff supraspinatus tendon tear using a texture analysis based on a histogram, gray level co-occurrence matrix (GLCM), and gray level run length matrix (GLRLM). METHODS: First, we applied a total of 57 features (5 first order descriptors, 40 GLCM features, and 12 GLRLM features) to each rotator cuff region of interest. Our results show that first order statistics (mean, skewness, entropy, energy, smoothness), GLCM (correlation, contrast, energy, entropy, difference entropy, homogeneity, maximum probability, sum average, sum entropy), and GLRLM features are helpful to distinguish a normal supraspinatus tendon and an abnormal supraspinatus tendon. The statistical significance of these features is verified using a t-test. The support vector machine classification showed accuracy using feature combinations. Support Vector Machine offers good performance with a small amount of training data. Sensitivity, specificity, and accuracy are used to evaluate performance of a classification test. RESULTS: From the results, first order statics features and GLCM and GLRLM features afford 95%, 85%, and 100% accuracy, respectively. First order statistics and GLCM and GLRLM features in combination provided 100% accuracy. Combinations that include GLRLM features had high accuracy. GLRLM features were confirmed as highly accurate features for classified normal and abnormal. CONCLUSIONS: This algorithm will be helpful to diagnose supraspinatus tendon tear on ultrasound images.ope

Biotechnology and Bioengineering

Biotechnology and Bioengineering presents the most up-to-date research on biobased technologies. It is designed to help scientists and researchers deepen their knowledge in this critical knowledge field. This solid resource brings together multidisciplinary research, development, and innovation for a wide study of Biotechnology and Bioengineering

Automated surgical light positioning system using thermal-imaging and optical techniques

Thesis (MEng)--Stellenbosch University, 2019.ENGLISH ABSTRACT: Surgical light systems (SLS) are used to ensure optimal light conditions during surgical procedures. At present, these light sources are adjusted manually by the surgeon or other operating room (OR) personnel. Manual adjustment of the SLS is problematic due to the necessity for a sterile environment. Surgeons must either adjust the SLS themselves, or communicate their requirements so that the OR assistants can position the lights to ensure optimal surgical conditions. Other complications with current SLS include mechanical problems, collisions, inaccessibility and illumination issues. It would be beneficial if the SLS could be automated to illuminate the wound without input from the surgeon. Therefore, the aim of this project was to test whether it is possible to identify a heat source (simulating a surgical wound), track this heat source in real time, and adjust a laser indicator (simulating a surgical light beam) mounted on an articulating assembly (analogous to an SLS). A system was developed that used an algorithm that identified and tracked a heat source and communicated to an automated articulating assembly to keep the laser indicator pointed at the heat source. The heat source was identified using thermal cameras and tracked using stereo optical cameras in three-dimensional space. The tracking accuracy and the manipulation accuracy were tested, and the results demonstrated that the combination of optical and thermal cameras with stereo image-processing techniques could be used to identify and track a heat source. This could further be used to guide an articulated assembly to keep a light beam pointed at the heat source with good accuracy. Therefore, this technology will contribute towards achieving full automation of SLS in the future. Following from the conclusions of this thesis, aspects have been identified and recommended for future research to achieve full automation and solve all SLS complications in the future.AFRIKAANSE OPSOMMING: irurgiese ligstelsels (CLS’e) word gebruik om optimale ligtoestande tydens chirurgiese prosedures te verseker. Tans word dit deur die chirurg of ander personeel in die operasiesaal (OS) verstel. Om die CLS met die hand te verstel, is problematies weens die vereistes van 'n steriele omgewing. Chirurge wat nie die CLS self verstel nie, moet hul vereistes so kommunikeer sodat die verstelling deur die OS-assistente voldoende is om optimale chirurgiese omstandighede te verseker. Ander komplikasies met die huidige CLS sluit in: meganiese probleme, botsings, ontoeganklikheid en beligtingskwessies. Dit sal dus voordelig wees as die CLS geoutomatiseer kan word om die wond te verlig sonder insette van die chirurg. Die doel van hierdie projek was dus om te toets of dit moontlik is om 'n hittebron (wat die chirurgiese wond voorstel) te identifiseer, hierdie hittebron te volg en 'n laseraanwyser (simulasie van die chirurgiese ligstraal) aan te pas met 'n ge-artikulerende arm (voorstelling van 'n CLS). 'n Stelsel is ontwikkel wat 'n algoritme gebruik om 'n hittebron te identifiseer en te volg. Die inligting is dan oorgedra na 'n gemotoriseerde artikulerende arm, om die laseraanwyser na die hittebron te rig. Termiese kameras het die hittebron geïdentifiseer terwyl stereo-optiese kameras gebruik is om die hittebron te volg soos wat dit beweeg het. Die akkuraatheid van die arm se beheer is getoets en die resultate het getoon dat die kombinasie van optiese en termiese kameras met stereobeeld-verwerkingstegnieke gebruik kan word om 'n hittebron te identifiseer en te volg. Dit kan verder gebruik word om 'n artikulerende arm aan te pas om 'n ligstraal te rig na die hittebron, met voldoende akkuraatheid. As gevolg van die akkuraatheid sal hierdie tegnologie in die toekoms bydra tot die volle outomatisering van CLS. Na aanleiding van die gevolgtrekkings van hierdie tesis, is daar sekere aspekte geïdentifiseer en aanbevelings gemaak vir toekomstige navorsing om volle outomatisering te bereik en alle SLS-komplikasies in die toekoms op te los

Applications of EMG in Clinical and Sports Medicine

This second of two volumes on EMG (Electromyography) covers a wide range of clinical applications, as a complement to the methods discussed in volume 1. Topics range from gait and vibration analysis, through posture and falls prevention, to biofeedback in the treatment of neurologic swallowing impairment. The volume includes sections on back care, sports and performance medicine, gynecology/urology and orofacial function. Authors describe the procedures for their experimental studies with detailed and clear illustrations and references to the literature. The limitations of SEMG measures and methods for careful analysis are discussed. This broad compilation of articles discussing the use of EMG in both clinical and research applications demonstrates the utility of the method as a tool in a wide variety of disciplines and clinical fields

Improved Orthopaedic Repairs through Mechanically Optimized, Adhesive Biomaterials

Despite countless surgical advances over the last several decades refining surgical approaches, repair techniques, and tools to treat tendon and tendon-to-bone injuries, we are still left with repair solutions that rely on fairly crude underlying mechanical principles. Musculoskeletal soft tissues have evolved to transfer high loads by optimizing stress distribution profiles across the tissue at each length scale. However, instead of mimicking these natural load transfer mechanisms, conventional suture approaches are limited by high load transfer across only a small number of anchor points within tissue. This leads to stress concentrations at anchor points that often cause repair failure as the sutures cut longitudinally through the fibrous tendon tissue like a wire cutting through cheese. Most tendon reconstruction ruptures occur within the first several weeks to months after repair, indicating that the initial strength of the repair is critical for its success. Over time under favorable conditions, the healing response can strengthen the repair sufficiently to function under typical physiologic forces. Here, we developed adhesive-based technologies to distribute load transfer more effectively across tendon and tendon-to-bone repairs, thus reducing peak stress and enabling repairs to sustain higher load before failure. First, we hypothesized that using the lateral surfaces along the length of suture to transfer load in shear would improve repair strength. We evaluated the mechanical principles of an adhesive-coated suture using a shear lag model to identify properties of suitable adhesives. Examination of the design space for an optimal adhesive demonstrated requirements for strong adhesion and low stiffness to maximize the strength of the adhesive-coated suture repair construct. When this design space was compared to real material properties in an Ashby plot, the model anticipated theoretical load transfer improvements of more than 7-fold over current tendon suture repairs using optimal elastomeric adhesives. We validated these model predictions experimentally using idealized single-strand pullout tests and clinically relevant flexor tendon repairs in cadaver canine flexor tendon. Clinically relevant repairs performed with Loctite 4903 cyanoacrylate-coated suture had significantly higher strength (17%) compared to standard repairs without adhesive. Notably, cyanoacrylate provided strong adhesion with high stiffness and brittle behavior, and was therefore not an ideal adhesive for enhancing suture repair. Nevertheless, the improvement in repair properties in a clinically relevant setting, even using a non-ideal adhesive, demonstrated the potential for the proposed approach to improve outcomes for treatments requiring suture fixation. We expanded this approach to assess the potential of adhesive films to increase the load tolerance of tendon-to-bone repairs. We hypothesized that adhesive films would redistribute load over the tendon footprint area where tendon inserts into bone, instead of focusing stress at just a few anchor points where suture from bone anchors punctures through tendon. Based on a shear lag model corroborated by a finite element model to establish the limits of the shear lag assumptions for thick or stiff adhesives, desirable adhesives again required compliance and high strength under shear loading. Models predicted an opportunity to increase transfer across tendon-to-bone repairs by over 10-fold. To rapidly evaluate adhesive mechanical properties for both applications using relevant tissue adherends, we developed a new method for consistent lap shear testing using tendon and bone planks. We validated shear lag predictions using this idealized test scenario and further assessed the ability of adhesives to provide additive benefit to rotator cuff repair strength using a clinically relevant human cadaver rotator cuff repair model with and without adhesive. Using this idealized adhesive testing platform, we demonstrated the potential of the proposed approach to improve outcomes in arthroscopic repair settings by applying a catechol-derived, marine mussel-mimetic adhesive with relevant mechanical properties that binds under water. Further study is needed to optimize adhesive binding properties and assess this approach in preclinical surgical tendon-to-bone repair scenarios. Finally, we developed a new approach to deliver adhesives and biofactors in tendon repairs using sutures with a porous outer sheath. These porous sutures were mechanically non-inferior to conventional sutures in single strand tests and clinically relevant tendon repairs. The porosity dramatically increased the suture surface area, which we conjectured would facilitate adhesive interdigitation and strong binding. Furthermore, this porous suture enabled growth factor or other bioactive factor addition to the inside of the suture for increased loading capacity and sustained release over the first 14 days, determined using connective tissue growth factor. In a clinically relevant canine in vivo injury and repair model, we assessed the effects of porous suture delivery of CTGF on the proliferative stage of repair at 14 days. This approach is hypothesized to act as a biological adhesive, increasing repair strength by modulating healing and encouraging tissue ingrowth into the suture pores. Taken together, these technologies represent dramatic departures from the traditional mechanical principles underlying tendon and tendon-to-bone repair, enabling large improvements in surgical repair strength without significantly changing the procedure in the operating room

Advancements and Breakthroughs in Ultrasound Imaging

Ultrasonic imaging is a powerful diagnostic tool available to medical practitioners, engineers and researchers today. Due to the relative safety, and the non-invasive nature, ultrasonic imaging has become one of the most rapidly advancing technologies. These rapid advances are directly related to the parallel advancements in electronics, computing, and transducer technology together with sophisticated signal processing techniques. This book focuses on state of the art developments in ultrasonic imaging applications and underlying technologies presented by leading practitioners and researchers from many parts of the world