Dissertations / Theses on the topic 'Radiographic changes'

A radiographic examination forms part of the pre-purchase examination of Thoroughbred yearlings at national sales in many countries. This data enables the recording of the prevalence of radiographic changes in selected Thoroughbred populations around the world and assists veterinarians in advising clients on the purchase of yearlings. This has financial implications for the client as well as the racing industry as a whole. Radiographic examinations of the 269 Thoroughbred yearlings lodged at the 2008 National Yearling Sale in Germiston, South Africa were collected and individually evaluated. The prevalence of radiographic changes was recorded and percentages calculated. These changes were compared to studies of other yearling populations. Radiographic changes present in the studied Thoroughbred population are: pedal osteitis 1.26%, metatarsophalangeal joint dorsal osteochondral fragmentation 1.60%, sagittal ridge changes 5.7%, ulnar carpal bone lucencies 8.33%, carpal osteophytes 1.19%, distal intertarsal and tarsometatarsal joint radiographic changes 9.92%, tarsal osteochondrosis lesions 4.4% and stifle joint osteochondrosis lesions 0.4%. These changes were found to be of lower prevalence when compared to similar studies. The prevalence of dorsal osteochondral fragments in the metacarpophalangeal joint was 1.60% which was similar to other studies. A higher prevalence of vascular channels was visible in the proximal sesamoid bones as well as irregular borders and lucencies. Palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments had a recorded prevalence of 2% and 7.10%, respectively, this prevalence being generally higher when compared to similar studies. There was an absence of palmar metacarpal disease, supracondylar lysis, proximal sesamoid bone fractures and carpal osteochondral fragmentation in the current study. Additional findings recorded in the current study were: proximal interphalangeal joint hyperextension (left front 15.13%, right front 18.91%), the solar angle (right front 2.38°, left front 2.79°), the prevalence of carpal bone one (30.95%) and carpal bone five (1.59%). The study population was limited to the radiographs lodged at the sale repository. As radiographic changes may influence sale price of the yearling, radiographs of yearlings with severe radiographic changes may not have been lodged at the repository. For these reasons the prevalence of radiographic changes recorded in the current study may not be a true reflection of the entire 2006 Thoroughbred foal crop. Further work to correlate radiographic changes to differences in management, pre-sale exercise programmes and genetics needs to be done. The effect of radiographic changes on the future performance of the Thoroughbred yearling also warrants further investigation. Copyright<br>Dissertation (MSc)--University of Pretoria, 2009.<br>Companion Animal Clinical Studies<br>unrestricted

Symptomatic apical periodontitis (SAP) is indicative of inflammation of the periodontal ligament. It may or may not be accompanied by radiographic changes and may occur with vital or necrotic pulpal diagnosis. Purpose of this study was to analyze clinical and radiographic presentations of SAP in a retrospective electronic dental chart and digital radiograph review utilizing the endodontic diagnostic template note of predoctoral dental school patients presenting with SAP. The aim was to determine prevalence of periapical radiolucencies (PARLs) in SAP, association of SAP to pulpal diagnosis, and define associated radiographic changes. Most prevalent pulpal diagnosis with SAP was symptomatic irreversible pulpitis (44%). A tooth presenting with SAP was more likely to have an intact lamina dura, but presented with a PARL 38% of the time. When a PARL was present the most common pulpal diagnosis was pulp necrosis however, 24.5% of teeth presented with a vital pulp diagnosis and lesions <2mm.

Reasons for performing this study: Metacarpal/metatarsal III condylar fractures are the most common type of fracture associated with Thoroughbred horseracing in the UK, and the most common reason for euthanasia on the racecourse. Prediction of fracture through quantification of exercise-related radiographic changes could enable modification of horse management to prevent this injury, improving animal welfare and reducing wastage. Objectives: The general aims were to validate objective radiographic measurement of exercise-related modelling in distal metacarpal III of Thoroughbred racehorses and to explore their utility for fracture prediction by comparing measurements from horses that sustained a fracture of the lateral condyle of distal metacarpal III with those from controls. The initial objective was to establish methods to measure objectively the following variables in distal metacarpal III: condyle opacity, cortical thickness and metaphyseal angle. Radiographic measurements were correlated with equivalent measurements derived from computed tomography (CT) to determine their accuracy. The second objective was to explore the ability of the radiographic measurements to identify horses at risk of fracture. This was done initially by comparing measurements made from radiographs taken at a single time point between Thoroughbred racehorses with and without a lateral condylar fracture, and subsequently by analysis of measurements from series of radiographs obtained prior to and at diagnosis of lateral condylar fracture as part of routine clinical practice. For the final objective, the maximum density of the palmar condyles of distal metacarpal III was determined using a quantitative CT-based technique. Maximum density was compared between horses with fractures and those without, and comparison made with the maximum opacity measured from radiographs, to investigate whether these measurements could be used to identify horses at risk of fracture. Materials and Methods: Fifty-five metacarpal III bones obtained from Thoroughbred racehorses euthanized on UK racecourses (age range 3-11 years) were divided in to three groups: control (no distal limb fracture, n=30), non-fractured (contralateral limb lateral condylar fracture, n=11) and fractured (lateral condylar fracture, n=14). All limbs were subjected to radiography and computed tomography for measurement of diaphyseal cortical thickness 2.5cm distal to the nutrient foramen (expressed as dorsal cortex:medulla width) and metaphyseal angle (deviation of the metaphysis relative to the diaphysis). Measurement of radiopacity of the medial and lateral condyles was calibrated using an aluminium phantom i (condyle:phantom ratio). Correlation between radiography and CT measurements and comparison of radiography measurements between groups was performed. For the longitudinal study, medical records of the Singapore Turf Club were reviewed. Thoroughbred racehorses diagnosed with a lateral condylar fracture that had also been radiographed in the previous 24 months were identified and placed in the ‘high risk’ group (n=16). Horses radiographed and then raced for a minimum of 2 years without suffering a fracture were placed in the ‘low risk’ group (n=15). Twenty-seven metacarpal III bones obtained from Thoroughbred racehorses euthanized on UK racecourses (age range 3-10 years) were used in the investigation of maximum density of the palmar condyles. They were divided in to three groups: control (no distal limb fracture, n=10), non-fractured (contralateral limb lateral condylar fracture, n=8), and fracture (lateral condylar fracture, n=9). Computed tomography measurement of condyle density was calibrated using a potassium phosphate phantom to enable comparison between age-matched bones. Results: Diaphyseal cortical thickness and metaphyseal angle measurements made by radiography and CT were significantly correlated (r=0.74, 0.73; p=0.007, 0.004) but there was no significant difference in measurements between groups. Radiopacity of medial and lateral condyles was significantly greater in non-fracture (0.67±0.04, 0.68±0.04) and fracture (0.82±0.07, 0.68±0.09) groups than the control (0.59±0.08, 0.57±0.09) group (p=0.003). The medial condyle (0.82±0.07) was significantly more radiopaque than the lateral condyle (0.68±0.09) in the fracture group only (p=0.001). In the longitudinal study, the dorsal cortex was thicker in high risk than low risk horses, the mean ± SD cortical thickness ratio of the high and low risk groups was 1.36 ± 0.26 and 1.08 ± 0.19 respectively (p=0.008). Metaphyseal angle measurement displayed a similar pattern and the difference was statistically significant, the mean ± SD metaphyseal angle of the high and low risk groups was 9.65° ± 2.21 and 6.95° ± 1.65 respectively (p=0.000). Computed tomography measurement of maximum density of distal metacarpal III, found no significant difference in maximum density of the lateral and medial palmar condyle between groups. There was a significant correlation between age and maximum density of the lateral condyle (r=0.44, p=0.019) and medial condyle (r=0.54, p=0.003). ii Conclusions: Objective measurement of dorsal cortical thickness and metaphyseal angle of distal metacarpal III can be performed accurately and precisely using radiography in Thoroughbred horses. Radiographic measurement of condyle opacity was precise but conclusions about the accuracy of this measurement await comparison with an appropriate reference standard. Increased radiopacity of the distal condyles was identified in horses that sustained lateral condylar fracture. However, this finding was not reflected by data from the horses represented by the clinical radiographs, suggesting that this measurement may not be useful in identifying horses at risk of fracture. Evidence supportive of this conclusion was provided by maximum density measurements made by CT. Significant differences in dorsal cortical thickness and metaphyseal angle were found between horses that sustained a lateral condylar fracture and horses that underwent radiography for clinical reasons but subsequently raced without fracture, suggesting that these variables could be of value in determining the risk of fracture and merit further investigation.

Radiographic examination of Thoroughbred racehorses at the time of the yearling sales is common practice in South Africa. Although it is generally accepted that yearlings will have some radiographic changes, there is only one study that estimated the prevalence of these changes in Thoroughbred racehorse yearlings in South Africa. Furniss et al reported on the occurrence of radiographic abnormalities over a one-year period (Furniss 2011). Furniss et al. study differs from other studies in that there was a higher prevalence of palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments and a lower prevalence of pedal osteitis, dorsal osteochondral fragmentation of the metatarsophalangeal joint, distal metacarpal saggital ridge changes, ulnar carpal bone lucencies, carpal osteophytes, distal intertarsal and tarsometatarsal joint changes, tarsal osteochondrosis lesions and stifle osteochondrosis lesions was found. This study will further assist practitioners to identify joints where the most prevalent changes are likely to occur. Our objective was to describe the prevalence and distribution of radiographic changes in the metacarpophalangeal joint, metatarsophalangeal joint, carpi, tarsi, stifle and fore digits of racing Thoroughbred yearlings in South Africa when examined as part of a pre-purchase examination during the Annual National Yearling Sales extending from 2008 through 2010. Thoroughbred racehorse yearlings were subjected to radiographic evaluation including the digit (n= 566 ), metacarpophalangeal joint (n=566 ), metatarsophalangeal joint (n= 566), carpi (n= 566), tarsi (n= 566) and stifle (n=566 ). The radiographic changes were categorised by location and type of change present for each series. The digit Where informal comparisons with previously published data can be made, similar changes of pedal osteitis were recorded in this study, with a total percentage of 6.7%. There was an 8.7% prevalence of inversion of the third pedal bone. Other studies describing radiographic changes in Thoroughbred racehorse yearlings did not investigate inversion of the third pedal bone, therefore results cannot be compared. The metacarpophalangeal and metatarsophalangeal joints with proximal The metacarpophalangeal and metatarsophalangeal joints with proximal sesamoid bones The prevalence of dorsoproximal phalanx one fragmentation (1.2%) of metacarpophalangeal joints were similar compared to other studies. Osteochondral fragmentation of proximal plantar phalanx one (6%) was 8.5 times more prevalent when compared to proximal palmar phalanx one (0.7%). The latter prevalence is in agreement with similar studies. There were low incidences of subchondral cyst-like lesions seen in distal third metacarpus (0.4%), distal third metatarsus (0.2%) and proximal first phalanx, similar to other studies. The most common change recorded on the dorsal aspect of distal third metacarpus and metatarsus was a well-defined semi-circular notch (dorsal aspect of distal third metacarpus 20.3%; dorsal aspect of distal third metatarsus 27%) similar to other studies. Our study showed a higher prevalence of lucencies present at dorsal aspect of distal third metacarpus (8.5%) and metatarsus (4.2%) compared to other studies. There was a marked lower prevalence in the current study of flat distal palmar third metacarpal condyles (6%). Prevalence of palmar and plantar third metacarpal and metatarsal supracondylar lysis were markedly higher in the present study. Slight palmar and plantar third metacarpus and metatarsus supracondylar lysis was seen in 19.3% of the horses. Moderate to extreme palmar and plantar third metacarpus and metatarsus supracondylar lysis were present in 10.2% of the horses. The carpi There was a higher prevalence of dorsomedial carpal disease in our study population (11.3%) and prevalence of carpal osseous cyst-like lesions such as a circular lucency in ulnar carpal bone was lower (14%). A markedly higher prevalence of 4.2% in carpal osteochondral fragmentation was found. The tarsi Osteochondrosis of the tarsocrural joint showed a similar prevalence (13.4 %). Degenerative joint disease of tarsometatarsal joint had a higher prevalence (36%) than the centrodistal (distal intertarsal) joint (20.3%). There was also a higher incidence of degenerative joint disease in tarsometatarsal joint (36%). The stifle In the current study, osteochondrosis of the stifle had a similar prevalence (3.6%) when compared to other studies. 6 Conclusion In South Africa Thoroughbred racehorse yearlings, radiographic changes most commonly involved the metacarpo- and metatarsophalangeal joints, carpi and tarsi. This study revealed markedly higher prevalence of palmar and plantar third metacarpal and metatarsal supracondylar lysis (slight 19.3% and moderate to extreme 10.2%), carpal osteochondral fragmentation (4.2%) and degenerative joint disease in tarsometatarsal joint (36%). Establishment of normal prevalence and distribution of radiographic changes in South Africa Thoroughbred yearlings will allow for comparison with populations of young horses worldwide. Knowledge of the normal prevalence will assist veterinarians to identify joints in which radiographic changes are most likely to occur.<br>Dissertation (MSc)--University of Pretoria, 2013.<br>gm2014<br>Companion Animal Clinical Studies<br>unrestricted

The aim of this investigation was to monitor attitudinal changes of staff and students participating in undergraduate professional programmes to the implementation of shared learning over a four-year period. The programmes being studied were the BSc. Occupational Therapy, BSc. Diagnostic Radiography and BSc. Therapeutic Radiography Honours degrees. Each validated programme contained some syllabus areas that were taught together i.e. were shared across the professions. Initially, after a review of the existing literature on this issue, a questionnaire was designed as a research tool to enable both qualitative and quantitative data to be collected and analysed. The quantitative sections of the questionnaire were checked for reliability throughout the four years and achieved positive Cronbach Alpha results ranging from .7083 to .8984 in the four main concepts under investigation, namely the Pitfalls, Benefits, Curriculum Aspects and Social Aspects of the shared programmes. Over the four year period a total of 418 student questionnaires were collected and analysed. In addition to the quantitative data collected, qualitative data were also collected from the questionnaire from extracts of the minutes of Course Committee and Examination Board meetings and from videos of tutorials and seminars. All of these were analysed. The results showed fluctuations in the attitudes of both staff and students to shared learning over the four year period, but all those who participated showed a net favourable change in attitude by the end of the research investigation.

Thesis (M.Ed. (Maximising Potential in Education and Training)) -- University of Pretoria, 2005.<br>Abstract and summary in English. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 28, 2007) Vita. Includes bibliographical references.

碩士<br>中山醫學大學<br>牙醫學系碩士班<br>104<br>Periodontal disease and tooth loss results in remarkable ridge destruction and resorption. Many investigations showed excellent results of osseous regeneration with bone substitute materials in alveolar ridge augmentation. Among those, calcium-based bone grafts have been widely used for hard tissue repair. Materials and Methods：The purpose of the present study was to compare the radiographic changes of three different calcium-based bone graft substitutes including HA/DCP, β-TCP, and calcium silicate (CS) using a minipig model. Bilateral mandible premolars P2, P3 and P4 of minipigs were extracted than filled with CS, HA/DCP, β-TCP or nothing, but blood clot as a sham control group. Mandible blocks were harvested after three and six months of material implantation. Specimens were evaluated with micro-computer tomography (micro-CT) analysis. The 6-month specimens were evaluated with histology observation. Results: The observation during surgery indicated that CS group had a better hemostasis property than s-TCP and HA/DCP groups possibly due to its unique setting merit. Micro-CT of 3-months specimens showed radiolucency around bone substitutes in the CS group. The bone volume/total volume (BV/TV) of s-TCP and HA/DCP groups were 42.9 ± 1.1% and 53.2 ± 4.0% respectively; the BV/TV of residual bone grafts were 4.2 ± 0.6% and 7.1 ± 1.2% respectively. No significant difference between HA/DCP and s-TCP groups regarding to the amount of new bone formation in three months. An increscent tendency of new bone formation in HA/DCP groups were found in 3 and 6-month micro-CT analysis which were 53.2 ± 4.0% and 69.6 ± 2.9% respectively, but without significant difference. Histological images showed no inflammation cells infiltration in blank and HA/DCP groups after 6-month of implantation. Conclusion and Suggestion: The result showed there were similar osteogenic potential and resorption rate between HA/DCP and s-TCP. To understand the in vivo osteogenesis of HA/DCP and CS bone substitutes prior to the clinical applications, the investigations of histological changes in shorter implantation time are needed.

Trabalho final do 5º ano com vista à atribuição do grau de mestre no âmbito do ciclo de estudos de Mestrado Integrado em Medicina Dentária apresentado à Faculdade de Medicina da Universidade de Coimbra.<br>Natural consequences of tooth extraction such as bone resorption and migration of the adjacent tooth create narrow mesio-distal edentulous spaces and mild Seibert Class I defects which can be challenging scenarios for clinicians. The decision of placing narrow-diameter implants with a flapped or flapless surgical technique has not been closely examined in the literature. Since NDIs have reduced contact areas with the bone in comparison with regular diameter implants, titanium alloys with higher tensile and yield strength have been used to manufacture NDIs. A titanium-zirconium (Ti-Zr) alloy has been developed (Roxolid®; Institut Straumann AG, Basel, Switzerland) from 83-87% titanium alloyed with 13-17% of zirconium. The combination of faster osseointegration with higher mechanical strength may allow implants made form Ti-Zr alloy be used in more daring clinical situations. Aim: The primary objective of this non-interventional prospective study is the evaluation of the radiographic bone level changes of Straumann® Roxolid® 3.3 bone level implants from loading to 5 years of follow-up. Secondary objectives include the determination of survival and success rate at 5 years of follow-up and assess, by quantitative 3D analysis, peri-implant soft tissue changes around reduced diameter TiZr Bone Level implants placed in crests with moderate facial resorption reconstructed using the roll flap technique 5 years after surgery. Material and Methods: Twenty patients with unitary or multiple edentulous gaps in the upper and lower jaw without need for vertical augmentation procedures were recruited between October 2009 and May 2010. Implant placement surgery was performed to install Straumann® Roxolid Bone Level implants with 3.3mm diameter. Definitive cemented restorations were placed after a minimum transmucosal healing period of 6 weeks. Follow-up appointment was scheduled 5 years after surgery. Patients who had completed the main study were invited to participate in the follow-up study. Eligible patients were required to attend a routine follow-up appointment for standard oral hygiene procedures, clinical evaluation of the rehabilitation and periapical radiographic examination. Dental casts of ten patients with unitary edentulous gaps in the maxilla (FDI positions 15 to 25) with moderate horizontal facial resorption of the residual ridge and no need for vertical augmentation procedures were 3D examined. Results: At 5 years, 17 of the 20 patients came in for the 5 years follow-up appointment. With a total of 25 out of 29 implants, retrieving a recall rate of 85% at the patient level and 86.2% at the implant level. Mean age of the controlled patients was 48 years old. The overall mean bone level variation from loading to 5 years (mesial and distal) was -0.07 ± 0.78mm. No correlation could be established between bone level changes and labial profile variation. Conclusions: Biomechanically the performance is excellent with survival rate of 100% which can be assigned to the mechanical properties of TiZr alloy associated with its biocompatibility. Narrow-diameter Ti-Zr implants performed well and without restrictions even in lower bone availability situations such as narrow crests over a 5-year period. Even though in our study no correlation could be established between bone level changes and labial profile, hard and soft tissues around reduced diameter TiZr Bone Level implants remained stable during the follow-up period of 5 years.

Neutron radiography is well suited to non-invasive imaging of water within metal containers. The goal of this work is to determine if neutron radiography can be used to image water freezing within a 1.6mm diameter capillary tube with the ultimate goal of observing this phenomena within fuel cells. In this work, radiography was completed at the Thermal Neutron Imaging Facility in the Nuclear Engineering Teaching Lab at The University of Texas at Austin. The source of neutrons was a TRIGA Mark II nuclear research reactor capable of 1.1 MW steady state power, which creates a neutron flux at the neutron imaging plane in beam port 5 of 5×10^6 neutrons/cm^2s. A scintillation screen and CCD camera are utilized to obtain digital radiographs, in which differences in pixel intensity are related to differences in neutron attenuation. An image processing algorithm was developed in Matlab to extract necessary data from each image, analyze water column images, and compare one to another. Also, a neutron flux model was implemented in Matlab in order to understand how a non-unidirectional neutron flux will affect final results. Raw image intensities of the water column in liquid and solid form were found to differ from expectations by at most 12.0% and 13.3%, respectively from the predictions of the Matlab flux model. A difference in pixel intensity comparing liquid water to solid water data is apparent and quantified. A ratio of pixel intensity for the ice image to the water image at full thickness of the water column is expected to be 1.038. Experimental results find a maximum ratio of 1.027, 1.1% off from expectations.<br>text

碩士<br>國立聯合大學<br>電機工程學系碩士班<br>106<br>The most common reason of periapical tissue disease is that the bacteria infect the root of tooth makes an acute or chronic inflammatory reaction occurred around, and it will not cause the tooth disease if it cures in time. According to the statistics, the number of people who goes for treatment in recent years due to the tooth disease is increasing. However, it is not impossible that periapical tissue disease cures. The dentist can complete the treatment by removing the irritant of the patient's root and confirming that the root lesion has not deteriorated again. Due to the bacterial infection of the tooth alveolar bone, the phenomenon that absorption and synthesis of bone cells are appeared on periapical X-ray images. So, dentist usually evaluate the recovery of tooth disease go better or worse by observing the grayscale difference and structure difference on X-ray images of the patient lesion. However, different doctors have different relevant training and clinical experience on interpreting images, it result the different interpretation results. Therefore, this study intends to develop a comprehensive and quantitative indicator of trabecular bone restoration levels, and further apply to clinical analysis and diagnosis. This study proposes a comprehensive quantitative indicator of the level of restoration of trabecular bone lesions in X-ray images, which is developed for the grayscale quantitative indicators and how to combine the structural quantitative indicators proposed in the previous research paper to form a comprehensive quantitative indicators. In terms of gray scale quantization, since the X-ray images at different times have inconsistencies in gray scale standards. Therefore, by using the gray level standardization of the X-ray image developed by this paper, the gray scale of the image is adjusted to the same standard, thereby calculating the objective gray scale quantization indicators. On the other hand, by observing the image lesion area, it is divided into two clusters with obvious gray scale difference and obvious structural difference. In this way, the corresponding weight reorganization with the highest correct rate is calculated, and a grayscale difference threshold is established as the judgment basis for using different weight combinations. Finally, the gray scale and the structural quantitative indicator are multiplied by the corresponding weights and added together to obtain a comprehensive and quantitative indicator. The difference of the lesion area in the X-ray image of the two time was taken as a group of samples, and the accuracy of the judgment under the total of 72 samples was 79.2%. In this paper, by simultaneously observing the difference between gray scale and structure change on X-ray images, and through the results of verification and analysis, a comprehensive and quantitative indicator with high objectivity and high accuracy is proposed and applied to assist dentist in clinical judgment.

Globalisation is affecting all social sectors, including education in ways that was never thought of before. In South Africa the most changing environment is probably the education sector. Higher education institutions in particular are constantly forging ways to develop the human resource capital for the country despite the shrinking financial resources. The increased demand for quality education, greater efficiency, accountability and national viability constantly challenge academics such that they can no longer wait for management to provide them with the necessary skills and competences. The times are calling for academics to take initiatives to develop themselves for improved performance in their primary roles and in the education of the learners. This study was undertaken to determine the changing nature of radiography as a profession and field of specialization, the development needs of radiography educators and the preferred strategies that could be used to develop the necessary skills and competences. A qualitative research design was employed and data collected through the literature review and interviews. Unstructured questions were used in the interviews to obtain an in-depth understanding of the situation. Challenges faced by academic radiographers in South Africa were explored and new competences required by academe during the time of change explained. Focus was put on the primary functions of academe and that includes teaching, research, community service/service learning and learner supervision strategies that can be used to improve the role of academe were described. Conclusions and recommendations regarding human resource development of academe were drawn from the literature review and the empirical investigation.<br>Dissertation (MEd (Maximising Potential in Education and Training))--University of Pretoria, 2006.<br>Curriculum Studies<br>unrestricted