Orientador: Alberto Cliquet Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-12T10:01:19Z (GMT). No. of bitstreams: 1 Rimkus_CarolinadeMedeiros_M.pdf: 11111626 bytes, checksum: de1ba0380bcffb39302c9f66bd9acfd4 (MD5) Previous issue date: 2008 / Resumo: A Junção craniocervical (JCC) é uma região anatômica de transição formada pelo osso occipital e pelas primeiras vértebras cervicais, o atlas e o axis. Esse arcabouço esquelético envolve importantes estruturas do sistema nervoso central (SNC), como o tronco cerebral, o cerebelo e a porção proximal da medula cervical. O complexo e delicado desenvolvimento embrionário dessa região sujeita essa topografia a diversas variações anatômicas e malformações congênitas. Embora algumas deformidades ósseas estejam presentes ao nascimento, alguns pacientes desenvolvem sintomas após a terceira ou quarta décadas de vida. Foi realizada a análise retrospectiva de imagens de Ressonância Magnética (RM) de 61 pacientes selecionados por apresentarem pelo menos uma das principais malformações esqueléticas ou antropométricas da JCC, discriminando a presença de compressão, alteração de sinal nas seqüências de TR longo e siringomielia. Observou-se correlação significativa entre a gravidade das malformações ósseas e o grau de comprometimento neural, com a maior redução ângulos clivuscanal (ACC) e o maior grau de invaginação basilar (IB) relacionando-se, principalmente, à compressão anterior e a alteração do sinal magnético no neuro-eixo. A siringomielia correlacionou-se à maior freqüência de invaginação tonsilar (IT). Alguns aspectos das malformações da JCC são francamente congênitos. Porém, a instabilidade crônica e a sobrecarga articular decorrentes de distúrbios biomecânicos impostos pelas deformidades esqueléticas podem se correlacionar a desordens osteoarticulares adquiridas. 19,7% desses pacientes apresentaram subluxação atlanto-axial, correlacionada com alterações morfológicas da vértebra occipital. Foram observados sinais de degeneração articular atlanto-axial em 42,6%, apresentando correlação significativa com assimilação atlanto-occipital (AAO). Foram realizadas análises de potenciais evocados auditivos do tronco cerebral (PEATC) em 8 pacientes. Dois pacientes não apresentavam compressão neural; 2 apresentavam compressão e elevação de sinal em T2, e 4 indivíduos tinham siringomielia. Um paciente sem compressão apresentou atraso em todas as ondas auditivas. Um dos pacientes com compressão e hipersinal em T2 apresentou as maiores latências nos intervalos I-III e I-V, demonstrando atraso global da via auditiva do tronco cerebral. Todos os pacientes com siringomielia apresentaram alargamento do intervalo I-V, mesmo após a abordagem cirúrgica da JCC. Todos os pacientes com sinais de lesão tecidual significativo, nos exames de RM, apresentaram assincronia dos picos após a aquisição binaural, com defasagem das ondas V do lado contralateral. A RM é uma ferramenta importante na avaliação morfológica da JCC. A avaliação global e detalhada das estruturas ósseas, ligamentares e neurais da JCC é indispensável para classificar o espectro das malformações congênitas e para predizer o risco de desenvolvimento de desordens osteoarticulares e neurológicas adquiridas. A idade do surgimento dos sintomas, algumas vezes, é discrepante ao tempo de duração da injúria tecidual. Por isso, questiona-se se o quadro fisiológico é secundário puramente às injúrias compressivas, ou se existem malformações ocultas do tecido neural. As análises dos PEATC não são realizadas de maneira rotineira, nesses pacientes. Os dados preliminares deste estudo demonstram que a correlação eletrofisiológica à análise por RM pode revelar aspectos da fisiologia do tronco cerebral e da etiologia das lesões neurológicas nas malformações da JCC. / Abstract: The craniocervical junction (CCJ) is formed by the combination of the occipital bone and the first cervical vertebrae, the atlas and the axis. It comprehends the brainstem, proximal cervical spinal cord and cerebelar structures and is subjected to several congenital anomalies and anatomic variations. Although the morphological abnormalities are present at birth, many patients develop symptoms after their third and fourth decades. Magnetic Ressonance Imaging (MRI) analyses were performed for 61 patients with these malformations towards discriminating the degree of compression, elevated signal in fluid sensitive sequences and presence of syringomyelia. The severity of skeletal disturbances correlated with the degree of neural tissue damage, with shorter skull base (represented by basilar hypoplasia) and higher basilar invagination (elevation of odontoid tip) correlating with compression and signals of tissue injury. The small posterior fossa correlated to a higher frequence of tonsilar invagination, and with higher incidence of syringomyelia. Some aspects of the CCJ malformations are trully congenital. But the chronical instability and the articular overload imposed by the skeletal deformities add biomecanical disturbances that can be correlated to acquired disorders. 19.7% of the patients presented atlanto-axial subluxation, correlated to morfological abnormalities classified as manifestations of the occipital vertebrae. Signals of degeneration of the atlanto-axial joints were shown in 42.6%, correlated to atlanto-occipital assimilation (AAO). Brainstem auditory evoked potentials (BAEP) tests were performed for 8 patients. 2 patients did not present compression of neuro-axis; 2 showed compression and magnetic signal alteration, and 4 presented syringomyelia. One of the patients without compression presented prolonged latencies of all evoked brainstem potential waves. One patient with compression and hyperintense signal in fluid sensitive sequences presented the longest delays in intervals I-III and I-V of auditory pathway. All patients with syringomyelia presented longer I-V interval, even after decompressive surgery. All patients with significant compromise to neural tissue presented assyncrhonic waves on binaural acquisition, with phase shift of wave V. MRI is an important tool to assess the morphological abnormalities of craniocervical junction. The comprehensive approach of the bone, ligamentar and neurological structures of the CCJ is important to classify the range of congenital abnormalities and to predict the risk of acquired articular and neurological compromise. The discrepance between the duration of compressive injury and appearence of symptoms does not allow the understanding wether functional impairment is secondary to compressive state or to unknown neural tissue incipient malformations. BAEP analyses of these patients are not routinelly done, and these previous data demonstrated that the image and functional correlation can lead to unrevealing features of morphophysiology of the craniocervical juntion malformations. / Mestrado / Pesquisa Experimental / Mestre em Cirurgia

Orientador: Paulo Sérgio Flores Campos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba. / Made available in DSpace on 2018-08-19T04:02:15Z (GMT). No. of bitstreams: 1 Bastos_LuanaCosta_M.pdf: 1562203 bytes, checksum: d439c2e66defcebe252381c8fef8dac4 (MD5) Previous issue date: 2011 / Resumo: Os objetivos do presente estudo foram: avaliar, através de exames de tomografia computadorizada de feixe cônico reconstruídos em nove protocolos, a capacidade de detecção de defeitos cavitários simulados no côndilo; e determinar subjetivamente a qualidade dessas imagens. Os defeitos foram criados com pontas diamantadas esféricas de três diâmetros diferentes (numerações 1013, 1016 e 3017) em 20 côndilos de 10 mandíbulas secas. As cavidades tinham o diâmetro da ponta utilizada (1,2, 1,8 ou 2,5mm) e profundidade correspondente à metade do diâmetro, resultando em defeitos que envolviam apenas a região cortical ou também a medular. As mandíbulas foram submetidas ao exame de tomografia computadorizada de feixe cônico e, a partir de um único protocolo de aquisição, foram realizadas reconstruções multiplanares seguindo nove protocolos diferentes com base na espessura do corte (0,2, 0,6 ou 1,0mm) e filtro (none - imagem sem filtro, Sharpen Mild e S9) utilizados. As imagens parassagitais geradas foram avaliadas por dois radiologistas com experiência em tomografia computadorizada. Os avaliadores, em duas diferentes sessões, deveriam indicar a existência ou inexistência dos defeitos, localizando-os (superfície superior ou posterior) quando presentes, e atribuir escores ao grau de definição da cortical condilar, à qualidade da visualização dos defeitos e à qualidade geral das imagens. Os dados gerados foram então tabulados e submetidos à análise estatística utilizando os coeficientes de Kappa (simples e ponderado) e os testes de McNemar e de simetria para testar a concordância inter e intra-avaliadores e, para comparar as taxas de acerto, foi utilizado o Teste do Qui-Quadrado. Também foi feita uma análise de variância (Teste de Tukey) para contemplar o efeito dos protocolos empregados. A proporção de acertos foi significativamente superior (p < 0,01) à proporção de erros para as duas superfícies observadas. Quando as médias de acertos foram comparadas, apenas para os defeitos na superfície posterior, foi encontrado um valor significativamente inferior para o Protocolo 7 (1,0mm e filtro none). Com relação à qualidade subjetiva das imagens, o Protocolo 9 (1,0mm e filtro S9) apresentou médias significativamente mais baixas para a definição da cortical condilar, qualidade da visualização dos defeitos na superfície superior e qualidade geral da imagem. O Protocolo 3 (0,2mm e filtro S9) teve média inferior, porém sem diferir estatisticamente dos demais, para a visualização dos defeitos na superfície posterior. Concluiu-se que a técnica se mostrou qualificada para identificação dos defeitos estudados e a maioria dos protocolos foi adequada para este fim. Com relação à qualidade subjetiva das imagens, deve-se evitar a combinação entre a espessura de corte de 1,0mm e o filtro S9. O filtro Sharpen Mild (independente da espessura de corte empregada) mostrou-se o mais equilibrado para a obtenção de imagens de qualidade adequada à identificação de defeitos cavitários na superfície articular do côndilo de mandíbulas secas / Abstract: The objectives of this study were to assess the ability to detect simulated cavitary defects in the condyle, using nine different reconstruction protocols of cone beam computed tomography scans; and to determine subjectively the quality of these images. Bone defects were created with spherical diamond tips of three different diameters (# 1013, 1016 and 3017) in 20 condyles of 10 dry mandibles. The defects had the same diameter as the tips (1.2, 1.8 or 2.5mm) and the depth corresponded to half diameter. This resulted in defects involving only the cortical or the medullar bony region too. The mandibles were submitted to cone beam computed tomography exam and, from a single acquisition protocol, multiplanar reconstructions were performed with nine different protocols based on section thickness (0.2, 0.6 or 1.0mm) and filter (none - no image filter, Sharpen Mild and S9) used. Two radiologists experienced in computed tomography evaluated cross-section images. The evaluators, in two different sessions, indicated the presence of the defects and also, they were asked to locate them (superior or posterior surfaces). Besides, they assigned scores to the degree of the condylar cortical definition, quality of visualization of defects and overall image quality. All data was tabulated and analyzed statistically using Kappa coefficients (simple and weighted) and McNemar's and symmetry tests to check the inter and intra-rater reliability and, to compare the accuracy rates, were used the Chi-Square Test. Analysis of variance (Tukey Test) contemplated the effect of the protocols used for each question. The proportion of the correct answers was significantly higher (p < 0.01) to the proportion of errors observed for the two surfaces. When the averages of correct answers were compared, only for defects on the posterior surface, a significantly lower value was found for the Protocol 7 (1.0mm and none filter). With respect to subjective quality of images, the Protocol 9 (1.0mm and S9 filter) showed significantly lower averages for the condylar cortical definition, quality of visualization of superior surface defects and overall image quality. Protocol 3 (0.2mm and S9 filter) presented lower average, but not statistically differ from the others, for the visualization of defects on the posterior surface. In conclusion, the protocols have proved suitable for the identification of cavitary defects in the mandibular condyle. With respect to subjective quality of images, the combination of thickness of 1.0mm and S9 filter should be avoided. The Sharpen Mild filter (regardless of the thickness used) was the most balanced to obtain images of sufficient quality to identify cavitary defects in the articular surface of dry mandibles condyles / Mestrado / Radiologia Odontologica / Mestre em Radiologia Odontológica

Orientador: Francisco Haiter Neto / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T04:17:39Z (GMT). No. of bitstreams: 1 CarneiroJunior_ElcioGomes_D.pdf: 4148945 bytes, checksum: 58cc0adb69ac56b9a8d827362333bfcf (MD5) Previous issue date: 2005 / Resumo: Este estudo tem por objetivo para comparar 3 tipos de imagem em cortes transversais. Foram utilizadas na pesquisa sete mandíbulas humanas secas e desdentadas na região de primeiro molar inferior. Nesta região, foram colocados marcadores radiopacos espaçados um do outro. Foram realizadas tomografias da região de primeiro molar inferior, utilizando diferentes espessuras de corte de três Tomógrafos Odontológicos Convencionais. Cada equipamento realizou um tipo de movimento tomográfico diferente: O aparelho Instrumentarium OP 100 realizou movimento linear, o aparelho Planmeca PROMAX realizou movimento linear corrigido e o aparelho Soredex TOME movimento espiral. Cinco avaliadores analisaram imagens produzidas e deram notas às imagens. Os dados foram submetidos à análise estatística. Comparando os aparelhos, foi possível verificar que o tipo de movimento tomográfico não alterou a nitidez imagem tomográfica. A comparação das imagens por espessura de corte foi possível verificar que o aparelho OP 100, gerou valores mais próximos aos relatados pelos fabricantes. Também, a espessura da camada de borramento foi variável dependendo da espessura de corte / Abstract: This study was designed to compare 3 modalities of cross-seccional imaging. On this work seven dry human mandibles on the first molar region were used. In this region radiopacs markers were placed within space between each marker. Some Tomography¿s exams were made at the first inferior molar, using different cut¿s thickness images from three conventional tomograph¿s machines. Each equipment had a different type of tomographic movement: the Instrumentarium OP 100 had a linear movement, the Planmeca PROMAX had a true linear movement and the Soredex TOME had the multidirectional movement. Five radiologists evaluated and scored the images. The data were submitted into a statistic¿s analysis. Comparing the machines, it was possible to verify that the tomography movement type had no effect on the diagnostic accuracy and quality. However comparing the images by cut¿s thickness, it was possible to verify that the OP 100 machine had the cut¿s thickness similar to manufacturer report. Moreover, depending on the cut¿s thickness the blurry layers vary / Doutorado / Radiologia Odontologica / Doutor em Radiologia Odontológica

M.Tech. (Radiography) / The ability to think critically is a vital skill for health care professionals in an era of rapidly advancing technology. Critical thinking skills improve problem solving ability, quality of clinical service and efficiency in delivering a clinical service. Although no specific curriculum exists within the Department of Radiography for teaching critical thinking, assessments given to students progress from the lower levels of learning, which include knowledge and understanding of information in first year, to the higher levels of learning, which include analysis, synthesis and evaluation in third year. The status of the students’ ability to demonstrate critical thinking skills needed to be explored for the Department of Radiography to develop a more explicit curriculum to facilitate these skills. The research question that arose was: To what extent could third-year radiography students demonstrate critical thinking skills and how can the design and delivery of the new professional bachelor’s degree be adapted to make provision for and best facilitate the teaching of these skills? The aim of this descriptive exploratory study was to determine the ability of third-year radiography students at a comprehensive university in Gauteng, South Africa, to think critically. The study employs a descriptive exploratory design. The participants responses to vignettes (in the form of clinical scenarios) were analyzed using a Likert scale and action verbs developed for evaluating evidence of critical thinking skills, providing quantitative data. Field notes were made whilst analyzing responses to each question, providing qualitative data.

Respiratory complications in dogs with cervical myelopathies can be life-threatening and are attributed to spinal cord morbidity secondary to cervical disease or decompressive surgery causing diaphragmatic dysfunction. However, diaphragmatic dysfunction in these dogs has not been described. Thirtyive client-owned dogs were recruited with 14 control and 21 test dogs. Dogs were evaluated for the presence of diaphragmatic dysfunction using radiography, M-mode ultrasonography, and fluoroscopy (gold standard) before and after an anesthetic or surgical event. Diaphragmatic dysfunction was observed more frequently in dogs with cervical disease prior to surgery (8/21 dogs, 38.1%) compared to control dogs (3/14 dogs, 21.4%) but was not statistically significant (odds ratio, 2.3; 95% confidence interval, 0.48-10.6; P = 0.30). Further, the frequency of diaphragmatic dysfunction did not significantly increase following surgical decompression in either group. Thus, dogs in this study with cervical disease and undergoing decompressive surgery were not considered to have a higher probability of diaphragmatic dysfunction compared to the control dogs.

Hetrotaxy syndrome is defined as an abnormality where the internal thoraco-abdominal organs demonstrate abnormal arrangement across the left-right axis of the body. Although it is a known condition among physicians taking care of pediatric patients, it is rarely seen in adult day-to-day medicine and most physicians involved in care of adult patients are unaware of it. It is important to recognize this anomaly based on clinical findings,due to its reported association with various medical conditions. We report a case of a 77-year-old patient diagnosed with Hetrotaxy syndrome.

Microvasculature can be found in almost every part of the human body, including the internal organs. Importantly, abnormal changes in microvasculature are usually related to pathological development of the tissue cells. Monitoring of changes in blood flow properties in microvasculature, therefore, provides useful diagnostic information about pathological conditions in biological tissues as exemplified in glaucoma, diabetes, age related macular degeneration, port wine stains, burn-depth, and potentially skin cancer. However, the capillary network is typically only one cell in wall thickness with 5 to 10 microns in diameter and located in the dermis region of skin. Therefore, a non-invasive flow imaging technique that is capable of depth sectioning at high resolution and high speed is demanded. Optical coherence tomography (OCT), particularly after its advancement in frequency domain OCT (FD-OCT), is a promising tool for non-invasive high speed, high resolution, and high sensitivity depth-resolved imaging of biological tissues. Over the last ten years, numerous efforts have been paid to develop OCTbased flow imaging techniques. An important effort is the development of phase-resolved Doppler OCT (PR-DOCT). Phase-resolved Doppler imaging using FD-OCT is particularly of interest because of the direct access to the phase information of the depth profile signal. Furthermore, the high speed capability of FD-OCT is promising for real time flow monitoring as well as 3D flow segmentation applications. However, several challenges need to be addressed; 1) Flow in biological samples exhibits a wide dynamic range of flow velocity caused by, for example, the iv variation in the flow angles, flow diameters, and functionalities. However, the improvement in imaging speed of FD-OCT comes at the expense of a reduction in sensitivity to slow flow information and hence a reduction in detectable velocity range; 2) A structural ambiguity socalled 'mirror image' in FD-OCT prohibits the use of maximum sensitivity and imaging depth range; 3) The requirement of high lateral resolution to resolve capillary vessels requires the use of an imaging optics with high numerical aperture (NA) that leads to a reduction in depth of focus (DOF) and hence the imaging depth range (i.e. less than 100 microns) unless dynamic focusing is performed. Nevertheless, intrinsic to the mechanism of FD-OCT, dynamic focusing is not possible. In this dissertation, the implementation of PR-DOCT in a high speed swept-source based FD-OCT is investigated and optimized. An acquisition scheme as well as a processing algorithm that effectively extends the detectable velocity dynamic range of the PR-DOCT is presented. The proposed technique increased the overall detectable velocity dynamic range of PR-DOCT by about five times of that achieved by the conventional method. Furthermore, a novel technique of mirror image removal called ‘Dual-Detection FD-OCT’ (DD-FD-OCT) is presented. One of the advantages of DD-FD-OCT to Doppler imaging is that the full-range signal is achieved without manipulation of the phase relation between consecutive axial lines. Hence the full-range DD-FDOCT is fully applicable to phase-resolved Doppler detection without a reduction in detectable velocity dynamic range as normally encountered in other full-range techniques. In addition, PRDOCT can utilize the maximum SNR provided by the full-range capability. This capability is particularly useful for imaging of blood flow that locates deep below the sample surface, such as v blood flow at deep posterior human eye and blood vessels network in the dermis region of human skin. Beside high speed and functional imaging capability, another key parameter that will open path for optical diagnostics using OCT technology is high resolution imaging (i.e. in a regime of a few microns or sub-micron). Even though the lateral resolution of OCT can be independently improved by opening the NA of the imaging optics, the high lateral resolution is maintained only over a short range as limited by the depth of focus that varies inversely and quadratically with NA. Recently developed by our group, ‘Gabor-Domain Optical Coherence Microscopy’ (GD-OCM) is a novel imaging technique capable for invariant resolution of about 2-3 m over a 2 mm cubic field-of-view. This dissertation details the imaging protocol as well as the automatic data fusion method of GD-OCM developed to render an in-focus high-resolution image throughout the imaging depth of the sample in real time. For the application of absolute flow measurement as an example, the precise information about flow angle is required. GDOCM provides more precise interpretation of the tissue structures over a large field-of-view, which is necessary for accurate mapping of the flow structure and hence is promising for diagnostic applications particularly when combined with Doppler imaging. Potentially, the ability to perform high resolution OCT imaging inside the human body is useful for many diagnostic applications, such as providing an accurate map for biopsy, guiding surgical and other treatments, monitoring the functional state and/or the post-operative recovery process of internal organs, plaque detection in arteries, and early detection of cancers in the gastrointestinal tract. Endoscopic OCT utilizes a special miniature probe in the sample arm to vi access tubular organs inside the human body, such as the cardiovascular system, the lung, the gastrointestinal tract, the urinary tract, and the breast duct. We present an optical design of a dynamic focus endoscopic probe that is capable of about 4 to 6 m lateral resolution over a large working distance (i.e. up to 5 mm from the distal end of the probe). The dynamic focus capability allows integration of the endoscopic probe to GD-OCM imaging to achieve high resolution endoscopic tomograms. We envision the future of this developing technology as a solution to high resolution, minimally invasive, depth-resolved imaging of not only structure but also the microvasculature of in vivo biological tissues that will be useful for many clinical applications, such as dermatology, ophthalmology, endoscopy, and cardiology. The technology is also useful for animal study applications, such as the monitoring of an embryo’s heart for the development of animal models and monitoring of changes in blood circulation in response to external stimulus in small animal brains.

<p>This research addresses low dose ionizing radiation exposure and risk. While it is well understood that high doses of radiation lead to deleterious health effects, there is controversy surrounding the definitive level of risk associated with exposure to low doses of radiation. These types of low level exposures are relevant to patients undergoing medical imaging procedures. This thesis considers the health effects associated with nuclear medicine, specifically positron emission tomography (PET), with the radiopharmaceutical 2-deoxy-2-(¹⁸F)fluoro-D-glucose(¹⁸F-FDG). These effects were studied in mice to eliminate the high degree of variability among human patients.</p> <p>The early response to various injection activities of ¹⁸F-FDG was first considered in terms of the DNA damage response in the haematopoietic cells of wild-type <em>Trp53+/+</em> mice. The late effects of PET scans with clinically relevant doses of ¹⁸F-FDG, such as carcinogenesis, were evaluated in cancer prone <em>Trp53+/-</em> mice. The role of p53 in the response to low dose radiation was also investigated to explore how short term responses correlate with p53-mediated cancer risk. This work has helped to advance the understanding of low dose radiation biology and the health risks associated with medical imaging procedures.</p> / Doctor of Philosophy (PhD)

No description available.

Yes / Increasing diagnostic capacity is a national priority to expedite the timeliness and appropriateness of patient treatment interventions. Imaging—encompassing a range of technologies including X-ray, CT, MRI, nuclear medicine and ultrasound—is a key diagnostic service and central to decision-making in most, if not all, disease pathways. However, imaging is an expensive discipline accounting for an estimated 3–5% of the annual NHS budget. As a result, it is imperative that we maximise service efficiency while optimising patient outcomes. / The manuscript version differs from the published version.