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Radiography has seen most development over the last 30 years with the evolution of new technologies, but perhaps more significantly changes in education models and radiographer roles. The development of advanced and consultant posts has facilitated the growth of the profession, although the evidence base is still evolving. Through a number of research projects this thesis will explore the growth in the radiography evidence base with specific reference to the extending role of the radiographer in image interpretation. Parallel clinical and academic developments have provided evidence of a scholarly profession which is slowly establishing its place through publication and a growing research base.

Digital radiography systems are important diagnostic tools for modern medicine. The images are produced when x-ray sensitive materials are coupled directly onto the sensing element of the detector panels. As a result, the size of the detector panels is the same size as the x-ray image. An alternative to the modern DR system is to image the x-ray phosphor screen with a lens onto a digital camera. Potential advantages of this approach include rapid readout, flexible magnification and field of view depending on applications. We have evaluated lens-coupled DR systems for the task of signal detection by analyzing the covariance matrix of the images for three cases, using a perfect detector and lens, when images are affected by blurring due to the lens and screen, and for a signal embedded in a complex random background. We compared the performance of lens-coupled DR systems using three types of digital cameras. These include a scientific CCD, a scientific CMOS, and a prosumer DSLR camera. We found that both the prosumer DSLR and the scientific CMOS have lower noise than the scientific CCD camera by looking at their noise power spectrum. We have built two portable low-cost DR systems, which were used in the field in Nepal and Utah. We have also constructed a lens-coupled CT system, which included a calibration routine and an iterative reconstruction algorithm written in CUDA.

Electrical parameter profiles of human breast images can be used to simulate and analyze the anticipated effects on tissue from its interaction with electromagnetic fields involved in the cancer treatment exposure. In part, the success of this approach depends on the accuracy and precision in identifying the different tissue types. In this work, we propose two methods of segmenting human breast images with malignant tumors. The first method of algorithmic partitioning of the image involves manual color-edge contouring of the tissues using a cursor and subsequent identification of the tissue types. For the second method, MRI T1 values and thresholds are used to perform segmentation and we investigate the potential of incorporating edge detection. The first method is effective, while the second lacks precision, but eliminates the need of manual contouring. The images are imported as BMP files into SEMCAD, an electromagnetic simulation tool based on finite-difference time-domain method, which recognizes the grouped tissues and creates a model of the image. The model allows the user to easily assign electrical parameter values to the grouped tissues, according to the measured values reported in the literature.

Die vorliegende Arbeit beschäftigte sich mit zwei Methoden zur Diagnostik der Aspergillose bei Greifvögeln, um neue Erkenntnisse über die Aussagekraft dieser nicht invasiven Diagnostika zu gewinnen. In der ersten Studie wurden bei ausschließlich Aspergillose-positiven Falken (Falco spp.) (n = 110) spezifische Röntgenzeichen an digital erstellten Röntgenbildern systematisch ermittelt und mit den typischen Röntgenzeichen von Papageien mit Erkrankungen des unteren Respirationstrakts verglichen. In der zweiten Studie wurden gesunde (n = 73) und an Aspergillose erkrankte (n = 32) Jagdfalken (Falco spp.) mittels Serumelektrophorese untersucht, Referenzwerte für die gesunden Falken erstellt und mit den Werten der erkrankten Falken verglichen. In beiden Studien stammten die Tiere aus dem Patientengut derselben Klinik. Bei der Auswertung von Röntgenbildern Aspergillose-positiver Falken wurden hauptsächlich subtile Röntgenzeichen beschrieben. Von den 110 Tieren waren 29 (26,4 %) radiologisch vollkommen unauffällig. Die am häufigsten beschriebenen Befunde waren inhomogene Verschattungen des Lungenfeldes (38,2 % laterolateral [ll]) und strichförmige Verschattungen der kaudalen Lungengrenze (30,0 % ll) sowie inhomogene (34,5 % ll; 29,1 % ventrodorsal [vd]) und streifige (26,4 % ll) Verschattungen der Luftsäcke, aber auch eine schlechte Abgrenzbarkeit des Herzschattens in der laterolateralen Projektion (42,7 %). Im Vergleich zu an Papageien mittels konventioneller Projektionsradiographie durchgeführten Studien war der Anteil an subtilen Röntgenzeichen geringer und der Anteil an massiven Röntgenzeichen größer. Verglichen mit Referenzwerten diverser Greifvogelspezies aus der Literatur zeigten die Referenzwerte der gesunden Falken dieser Studie unter Verwendung des hochauflösenden Elektrophoresesystems SAS 1 unit (Helena, Saint Leu La Forest, Frankreich) relativ niedrige Gesamtproteinwerte und relativ hohe Präalbuminwerte auf. Bei den 32 Serumproben der an Aspergillose erkrankten Falken ließ sich im Gegensatz zu den 73 Serumproben der gesunden Falken ein signifikant erniedrigter Totalalbuminwert (Albumin + Präalbumin) sowie ein hoch signifikant erniedrigter Präalbuminwert mittels Serumelektrophorese feststellen. Obwohl die Falken meist schon in frühen Krankheitsstadien vorgestellt wurden und die Diagnostik in diesen Stadien besonders schwierig ist, konnten mit beiden Untersuchungsmethoden von gesunden Tieren differierende Befunde erhoben werden. Diese in Zusammenhang mit Aspergillose erhobenen Befunde wichen jedoch teilweise deutlich von den in der Literatur beschriebenen „typischen“ Befunden bei an Aspergillose erkrankten Vögeln ab. Dies kann damit erklärt werden, dass die meisten vergleichbaren Studien an als Heimtiere gehaltenen Papageien oder gefangen gehaltenen Zoovögeln (von Falken abweichende Haltungsform, Anatomie und Physiologie sowie Leistungsniveau) und mit unterschiedlicher Technik (digitale versus konventionelle Projektionsradiographie, unterschiedliche Elektrophoresesysteme und Verwendung von Serum anstelle von Plasma) durchgeführt wurden. Die digitale Projektionsradiographie kann aufgrund ihrer schonenden, einfachen und schnellen Durchführbarkeit sowohl den Vogelmedizin spezialisierten Institutionen als auch den Kleintierpraktikern uneingeschränkt empfohlen werden. Die Proteinelektrophorese kann bis zum heutigen Zeitpunkt nur bedingt für den Praktiker, wohl aber für spezialisierte Institutionen bei Beachtung aller Besonderheiten als zusätzliches Diagnostikum empfohlen werden. / The present study concentrates on two methods for diagnosing birds of prey with aspergillosis with the intent to increase the knowledge of the validity of these non-invasive diagnostic methods. In the first study, specific radiographic signs of digitally created radiographs of falcons (Falco spp.) which were exclusively positive for aspergillosis (n = 110) were systematically analyzed and compared to the typical radiographic signs of parrots with diseases of the lower respiratory tract. In the second study, healthy falcons (n = 73) and falcons affected with aspergillosis (n = 32) (Falco spp.) were examined by using serum protein electrophoresis in order to create reference values for healthy falcons and compare them with the values of the affected falcons. In both studies, the animals were patients of the same clinic. While evaluating the radiographs of the falcons with aspergillosis, mainly subtle radiographic signs were described. Radiographically within normal limits were 29 (26.4%) of the 110 animals. The most commonly reported findings were inhomogeneous increased radiodensity of the lung area (38.2% laterolateral [ll]), line-shaped shadowings of the caudal lung border (II 30.0%) as well as an inhomogeneous (34.5% ll, 29.1% ventrodorsal [vd]) and streaky (26.4% II) radiodensity of the air sacs, but also a poor delineation of the cardiac silhouette in the laterolateral projection (42.7%). Compared to studies performed on parrots by conventional radiography, the portion of subtle radiographic signs was lower and the portion of severe signs was higher. Compared to reference values of various raptor species from the literature, this study, which made use of the high-resolution electrophoresis SAS 1 unit (Helena, Saint Leu La Forest, France), revealed relatively low values for total proteins and relatively high values for prealbumin in the reference values of the healthy falcons. The 32 serum samples of the falcons suffering from aspergillosis showed a significantly reduced total albumin (albumin + prealbumin) level and a highly significantly reduced prealbumin level compared to the 73 serum samples of healthy falcons. Although the falcons were for the most part already brought to the clinic in one of the early stages of the disease, when diagnosing aspergillosis is particularly difficult, both examination methods revealed different results for the healthy and diseased animals. However, the findings related to aspergillosis were in some cases significantly different from those described in the literature as the \"typical\" findings in birds suffering from aspergillosis. This can be explained by the fact that most of the comparable studies were conducted with parrots held as pets or with captive zoo birds (when husbandry, anatomy and physiology, as well as performance level are different from falcons) and with a different technique (digital versus conventional radiography, different electrophoresis systems and the use of serum instead of plasma). The digital radiography can be fully recommended for specialized medical institutions for avian medicine as well as for small animal practitioners because of its easy, rapid and gentle feasibility. To date, the protein electrophoresis can only be recommended with restrictions for practitioners, however for specialized institutions, it can be useful as additional diagnostic tool if all its specific features are taken into account.

No description available.

Elk (Cervus elaphus) in eastern Kentucky appear to have increased in number since reintroduction in 1997, but rugged landscapes and cryptic elk behavior have precluded use of typical population survey methods to accurately estimate population size. In December 2006, I used forward-looking infrared radiography (FLIR) to survey the elk population in eastern Kentucky. Elk locations identified by FLIR were used to create a landscape based model to estimate the density distribution of elk within a 7,088 km2 core area of the elk restoration zone. FLIR detected 76% of elk groups of < 10 individuals and 100% of elk groups of ≥ 10 individuals. The density of elk was positively associated with the amount of herbaceous area, herbaceous edge, herbaceous area weighted mean patch fractal dimensions, proximity to release sites, the number of elk released at each site and urban core area index, and negatively associated with road density. My model estimated the elk population at 7,001 (SE = 772, 95% CI = 5,488- 8,514) individuals within the core area, 53% of which were < 10 km from release sites. The predicted elk distribution pattern and abundance estimate derived from this model will be important for wildlife managers in successfully managing the Kentucky elk population.

Andreas Starke Quantifizierung und Klassifizierung der kaninen Ellbogeninkongruenz auf Grundlage einer standardisierten Röntgen- und Messmethode Klinik für Kleintiere der Veterinärmedizinischen Fakultät der Universität Leipzig (79 Seiten, 27 Abbildungen, 8 Tabellen, 132 Literaturangaben) Zielstellung: Ziel der vorliegenden Arbeit war die objektive Quantifizierung der knöchernen Konformation des Ellbogengelenkes gesunder und erkrankter Hunde unter standardisierten Bedingungen. Dazu sollte eine Methode entwickelt werden mit der Röntgenaufnahmen von Ellbogen unter Belastung angefertigt und anhand von Messungen an markanten Knochenstrukturen evaluiert werden können. Diese standardisierte Röntgen- und Messmethode sollte an einer Kontrollgruppe getestet werden, um die Eignung der Methodik zu untersuchen und Referenzwerte zu erstellen. Besonderer Schwerpunkt war die Überprüfung der Reliabilität der Messungen in Abhängigkeit von Lagerungsartefakten und Messwiederholungen. Danach sollten Ellbogengelenke klinisch erkrankter Hunde untersucht und mit den Ergebnissen der Kontrollgruppe verglichen werden, um herauszufinden, ob sich die Messergebnisse signifikant von gesunden Gelenken unterscheiden. Zudem wurde die Hypothese aufgestellt, dass sich die dysplastischen Ellbogengelenke anhand der röntgenologischen Messparameter in unterschiedliche Formen der humeroulnaren und humeroradialen Inkongruenz unterteilen lassen. Material und Methode: Bei 27 lahmheitsfreien Hunden wurden von 47 Ellbogengelenken Röntgenaufnahmen mit und ohne Belastung (mediolateral, kraniokaudal; Aufnahmen am liegenden, narkotisierten Tier) sowie Aufnahmen im Stehen (kraniokaudal) untersucht. Digital gemessen wurden subchondrale Gelenkspaltenabstände, subchondrale Knochenabstände und ein Winkel. Anschließend wurden 149 Hunde mit ED der Röntgen- und Messmethode unterzogen und mit den Ergebnissen der Kontrollgruppe verglichen. Anhand von gehäuft auftretenden Messwertabweichungen wurden die 149 Hunde in Untergruppen eingeteilt und erneut mit der Kontrollgruppe verglichen. Danach wurden 4 Gruppen mit jeweils unterschiedlicher Osteotomie an Radius bzw. Ulna zur zwei- und dreidimensionalen Gelenkumstellung erstellt (euthanasierte Hunde ohne Ellbogenerkrankung), der gleichen Röntgen- und Messprozedur unterzogen und mit der Kontrollgruppe und den Gruppen der kranken Hunde verglichen. Ergebnisse: Eine standardisierte und reliable Lagerung sowie Längen- und Winkelmessungen an definierten Knochenpunkten konnten mit und ohne Belastung bei gesunden und kranken Hunden etabliert werden. Mittels Normalisierung der Parameter der Längenmessungen gelang eine Vergleichbarkeit zwischen unterschiedlichen Gelenken und Projektionsebenen herzustellen. Messwerte von Aufnahmen im Stehen zeigten viele Lagerungsartefakte und eine geringe Reliabilität. Von den einzelnen Messparametern der Aufnahmen mit und ohne Belastung konnten aufgrund ihrer geringen Streuung Normwerte von der Kontrollgruppe abgeleitet werden. Eine deutliche Abgrenzung auf Grundlage signifikanter Unterschiede führte zur Bildung der Untergruppen Typ I (n=60), Typ II (n=40) und indiff (n=49) innerhalb der 149 Hunde mit ED. Unterscheidungskriterien für die Einteilung eines kranken Ellbogengelenkes in Typ I, Typ II und indiff waren 3 subchondrale Gelenkspaltenabstände (mp3, mp4, mp6), 3 aus Gelenkspaltenabständen errechnete Indizes (LI 3, LI 4, LI 6) und ein Winkel. Diese Parameter wiesen in der Kontrollgruppe eine hohe Reliabilität auf. Durch die Osteotomiemodelle konnten Parallelen zwischen Typ I und einer short ulna sowie zwischen Typ II und einem short radius ermittelt werden. Schlussfolgerungen: Röntgenaufnahmen am stehenden Hund sind nicht praktikabel, nur bedingt auswertbar und daher nicht geeignet. Anhand von Röntgenbildern mit und ohne Belastung lassen sich dagegen die Knochenverhältnisse im Gelenk beschreiben und Normwerte erstellen. Die untersuchte Methodik ist geeignet 67% erkrankter Tiere einem Inkongruenztyp (Typ I oder Typ II) zuzuordnen. Die Ergebnisse der dreidimensionalen Ulnaverkürzung und dreidimensionalen Radiusverkürzung weisen auf dreidimensionale Bewegungen der Knochenoberflächen bei Typ I bzw. Typ II im und am Gelenk hin. Ob Ellbogengelenke des Typ I (40%) von einer dreidimensionalen Osteotomie der proximalen Ulna und Ellbogengelenke des Typ II (27%) von einer Radiuselongation profitieren würden, müssen weitere Untersuchungen zeigen. Die Inkongruenz selbst konnte nicht näher quantifiziert werden. / Andreas Starke Quantification and classification of canine elbow incongruency using a standardized method for radiography and measurement Department of Small Animal Medicine, Faculty of Veterinary Medicine, Universitiy of Leipzig (79 pages, 27 Figures, Tables, 132 references) Objective: Goal of this paper was the objective quantification of elbowjoint conformation for healthy and diseased dogs under standardized conditions. Therefor we developed a method for taking x-rays of the elbow joint under load to facilitate measurements using bone-landmarks. For this we aimed to test a standardized X-ray- and measurement methodology on a control group for evaluation of the developed methodology and to compile reference values. Emphasis has been placed on the validation of the reliability of the taken measurements especially were positioning artefacts and repeat measurements were concerned. Subsequently we examined elbow joints of clinically affected dogs and compared the results to that of the control group to determine whether signifikant differences can be found in the measurements compared to those taken in joints of healthy dogs. Additionally we formulated the hypothesis that displastic Elbow joints can be grouped into humero-ulnar and humero-radial incongruencies using the developed method of measurement. Material and methods: Plain x-rays and standardized stressed x-rays (medio-lateral, cranio-caudal taken under sedation; cranio-caudal views taken while standing) of 47 elbow-joints of 27 lameness free dogs were examined. We digitally measured subchondral jointgaps, subchondral bone gaps and an angle. Afterwards 149 dogs with ED were examined using our standardized X-ray method and we compared the results to the control group. The 149 dogs were divided into subgroups using frequent measurement deviances and the subgroups again compared to the control group. Afterwards we created 4 groups based on the kind of radial or ulnar osteotomy for two- and three- dimensional joint adjustment, took measurements based on our standardized X-ray method and compared the results to the control group and ED group. Results: A reliable standardized X-ray methodology as well as length and angle measurement on defined bone landmarks with and without load could be established on healthy dogs and those with ED. Using normalization of length-measurements we were able to establish comparability between different joints and projections. Measurements from x-rays taken in a standing position showed a lot of positioning related artefacts and low reliability. We were able to compile standard values from x-rays of the control group taken with- and without load due to the low deviation of the norm values. Due to marked delination based on significant differences we were able to establish subgroups Typ I (n=60), Typ II (n=40) and Group indiff (n=49) in the ED Group. Distinction Criterions to classify an ED elbow joint in Types I, II or indiff were 3 subchondral jointgaps (mp3, mp4, mp6), three indices calculated out of joint gaps (LI 3, LI 4 and LI 6) and an angle. In the control group these parameters showed a high reliability. Using an osteotomy model we were able to draw parallels between Typ I and a short Ulna, as well as Typ II and a short radius. Conclusions: X-rays taken in a standing position are not feasible. Using x-rays taken with and without load we were able to adequately describe bone-marker relations and could compile norm values. Using our developed method we have been able to assign 67% of the examined diseased joints to a type of incongruency (Type I or II). The results of three dimensional ulna and radius shortening indicate three dimensional movement of the bone surface in Typ I or II in the joint. Whether elbow joints of Typ I (40%) benefit of a three dimensional proximal ulna-osteotomy or joints of Typ II (27%) would benefit of a radial elongation needs to be shown in further studies.

Studies of diagnostic accuracy often report paired tests for sensitivity and specificity that can be pooled separately to produce summary estimates in a meta-analysis. This was done recently for a systematic review of radiographers' reporting accuracy of plain radiographs. The problem with pooling sensitivities and specificities separately is that it does not acknowledge any possible (negative) correlation between these two measures. A possible cause of this negative correlation is that different thresholds are used in studies to define abnormal and normal radiographs because of implicit variations in thresholds that occur when radiographers' report plain radiographs. A method that allows for the correlation that can exist between pairs of sensitivity and specificity within a study using a random effects approach is the bivariate model. When estimates of accuracy as a fixed-effects model were pooled separately, radiographers' reported plain radiographs in clinical practice at 93% (95% confidence interval (CI) 92-93%) sensitivity and 98% (95% CI 98-98%) specificity. The bivariate model produced the same summary estimates of sensitivity and specificity but with wider confidence intervals (93% (95% CI 91-95%) and 98% (95% CI 96-98%), respectively) that take into account the heterogeneity beyond chance between studies. This method also allowed us to calculate a 95% confidence ellipse around the mean values of sensitivity and specificity and a 95% prediction ellipse for individual values of sensitivity and specificity. The bivariate model is an improvement on pooling sensitivity and specificity separately when there is a threshold effect, and it is the preferred method of choice.

No description available.