As fraturas do planalto tibial são lesões com um espectro muito variado de manifestação clínica. Diversos sistemas de classificação foram desenvolvidos para facilitar a compreensão e a tomada de decisões no tratamento dessas lesões. O presente estudo teve como objetivo primário avaliar o impacto da tomografia computadorizada na concordância inter e intraobservador da classificação de Schatzker. Além disso, procurou-se avaliar o impacto da tomografia computadorizada na tomada de decisões a respeito da via de acesso cirúrgico ao planalto tibial, utilizando para esta análise a classificação de Schatzker modificada por Kfuri. Um banco de dados com imagens de 70 pacientes, incluindo radiografias, tomografia computadorizada e reconstruções tridimensionais computadorizadas foi oferecido a um grupo de 10 observadores para análise. Como resultados, observou-se que a classificação de Schatzker apresentou coeficiente de concordância moderado, quando baseado no uso de radiografias (k=0,58), e substancial quando esta análise foi complementada por tomografia (k=0,62/0,64). A nova classificação de Schatzker modificada por Kfuri obteve nível moderado de concordância interobservador (k=0,53) e substancial intraobservador (k=0,63). A tomografia computadorizada, elemento básico da nova classificação, influenciou decisivamente os cirurgiões a mudarem a opção pela via de acesso cirúrgico, especialmente em fraturas com orientação no plano coronal. Como conclusão, verificou-se que a classificação de Schatzker modificada por Kfuri demonstrou substancial índice de concordância intraobservador e moderado índice de concordância intraobservador, e devem ser úteis para a prática clínica. / Tibial plateau fractures are lesions with a varied spectrum of clinical presentation. Several classification systems have been developed to facilitate the understanding and decision making in the treatment of these injuries. The present study aimed to evaluate the impact of computerized tomography on the inter and intraobserver correlation of the Schatzker classification. In addition, we sought to evaluate the impact of the computed tomography in the decision making regarding the surgical approaches to the tibial plateau, using the Schatzker classification modified by Kfuri for this analysis. A database of 70 patient images, including radiographs, computerized tomography, and computerized three-dimensional reconstructions were offered to a group of 10 observers for analysis. As a result we observed that the Schatzker classification presents a moderate agreement when based on radiographs (k=0,58) and substantial when this analysis is complemented by tomography (k=0,62/0,64). The new Schatzker classification modified by Kfuri has a moderate level of interobserver agreement (k=0,53) and substantial intraobserver agreement (k=0,63). Computerized tomography, a basic element of the new classification, decisively influenced surgeons to change the option for surgical access, especially in fractures with orientation in the coronal plane. In conclusion, the Schatzker classification modified by Kfuri have a substantial intraobserver and moderate interobserver correlation, and should be useful for clinical practice.

Computed tomography (CT) is routinely used for diagnosing lung disease and developing treatment plans using images of intricate lung structure with submillimeter resolution. Automated segmentation of anatomical structures in such images is important to enable efficient processing in clinical and research settings. Convolution neural networks (ConvNets) are largely successful at performing image segmentation with the ability to learn discriminative abstract features that yield generalizable predictions. However, constraints in hardware memory do not allow deep networks to be trained with high-resolution volumetric CT images. Restricted by memory constraints, current applications of ConvNets on volumetric medical images use a subset of the full image; limiting the capacity of the network to learn informative global patterns. Local patterns, such as edges, are necessary for precise boundary localization, however, they suffer from low specificity. Global information can disambiguate structures that are locally similar. The central thesis of this doctoral work is that both local and global information is important for segmentation of anatomical structures in medical images. A novel multi-scale ConvNet is proposed that divides the learning task across multiple networks; each network learns features over different ranges of scales. It is hypothesized that multi-scale ConvNets will lead to improved segmentation performance, as no compromise needs to be made between image resolution, image extent, and network depth. Three multi-scale models were designed to specifically target segmentation of three pulmonary structures: lungs, fissures, and lobes. The proposed models were evaluated on a diverse datasets and compared to architectures that do not use both local and global features. The lung model was evaluated on humans and three animal species; the results demonstrated the multi-scale model outperformed single scale models at different resolutions. The fissure model showed superior performance compared to both a traditional Hessian filter and a standard U-Net architecture that is limited in global extent. The results demonstrated that multi-scale ConvNets improved pulmonary CT segmentation by incorporating both local and global features using multiple ConvNets within a constrained-memory system. Overall, the proposed pipeline achieved high accuracy and was robust to variations resulting from different imaging protocols, reconstruction kernels, scanners, lung volumes, and pathological alterations; demonstrating its potential for enabling high-throughput image analysis in clinical and research settings.

Despite affecting many organ systems, the leading cause of morbidity and mortality in the cystic fibrosis (CF) population is lung disease. For the current studies we investigated elements of CF lung disease in a porcine model of CF and in people with CF. Our primary analysis tool was chest computed tomography (CT). To investigate early CF lung disease we examined three week old CF and non-CF pigs. We found three week old CF pigs to have large, irregular tracheal smooth muscle bundles, airways of reduced size, airways of irregular shape, and airways of abnormal distensibility. Three week old CF pig lung parenchyma was more heterogenous in density than three week non-CF pigs, especially in the right cephalad lung. The degree of lung tissue heterogeneity in CF pigs correlated with the degree of lung infection. Three week old CF pigs also had significantly more air trapping upon exhalation, evidence of airflow obstruction, than non-CF pigs. The degree of air trapping correlated with the degree of mucus accumulation in the airways. These data show that CF pigs spontaneously develop hallmark features of CF lung disease within weeks of birth, and that abnormal airway growth and development in CF may contribute to lung disease. This study helped set the foundation for future comparative studies involving CF therapeutics, for example, antibiotics and mucolytics. In adults with CF we performed a before drug, after drug study. The drug was ivacaftor, and it restores the basic underlying defect in a subset of people with CF: impaired function of a particular anion channel. We hypothesized that abnormal airway smooth muscle behavior in people with CF, known as “CF asthma,” is, in part, a primary pathogenic mechanism of CF lung disease. We tested our hypothesis by assaying smooth muscle tone before and after administration of ivacaftor. We limited the time duration to two days. We reasoned two days was long enough for ivacaftor to become effective, but not long enough to reverse long standing lung infection and inflammation which could affect smooth muscle function independently. The implication being, that observed changes would be directly due to restoration of the CF defect. We found evidence suggesting relaxation of airway and vascular smooth muscle tone. And, the change in airway smooth muscle tone correlated with the change in vascular smooth muscle tone. These data suggest that impaired smooth muscle function is a primary element of CF lung disease. Many of the people in our two day ivacaftor study returned for follow up after one year of ivacaftor therapy. We hypothesized that radiographic features of lung disease would improve following one year of ivacaftor therapy. We observed no change in lung volume upon inspiration, but a reduction in expiratory lung volume, approximately half of which occurred within two days. Our airway measurements were confounded by errors in scan reconstruction, however, other published studies report airway wall thinning over long term ivacaftor administration. Taken together, these studies of pigs with CF and people with CF, help us understand this disease.

Orientador: Cesar Augusto Moreira / Resumo: A área de estudo está localizada próxima a Caçapava do Sul no estado do Rio Grande do Sul, ocorrência conhecida como Colônia Santa Barbara. A ocorrência está situada na Bacia do Camaquã, alocada estruturalmente em um bloco alto, na interseção de duas falhas com direções NE-SW e NW-SE, com litologias aflorantes pertencentes ao Complexo Metamórfico Bossoroca e Formação Hilário do Grupo Bom Jardim. Descrita entre 1960 e 1970, a pesquisa foi suspensa após análise geoquímica apontar teores de cobre insatisfatórios, não ultrapassando a 1%, sem interesse econômico. Atualmente com uso de aparelhos multi-cabos de aquisição automática é possível a realização de ensaios geoelétricos de diferentes arranjos em menor tempo e maior praticidade, o que impulsionou o desenvolvimento deste trabalho. Essa dissertação apresenta a análise comparativa dos dados de tomografia elétrica em arranjo Schlumberger, Wenner e Dipolo-Dipolo, para averiguar o resultado que descreva a morfologia mais realista esperada do jazimento, baseado no modelo magmático hidrotermal com forte controle estrutural. A análise comparativa entre os arranjos de tomografia elétrica proposta neste trabalho revelou a conformação de um corpo cônico de alta cargabilidade (2,7 mV/V) que engloba o núcleo vertical de alta resistividade (438 Ω.m), além de uma zona anelar de alta cargabilidade possivelmente correlacionada ao sistema de falhas que estruturam o alto estrutural (tufo vulcânico). A estrutura cônica observada é compatível com... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study area is located near to Caçapava do Sul, at Rio Grande do Sul State, an occurrence known as Colônia Santa Barbara. The occurrence is in the Camaquã Sedimentary Basin, structurally allocated in a high block, at the two faults intersection with NE-SW and NW-SE directions, with outcropping lithologies belonging to Bossoroca Metamorphic Complex, and Hilario Formation. Described between 1960 and 1970, the research was suspended after geochemical analysis pointed to unsatisfactory copper levels, not exceeded 1%, without economic interest. Nowadays, with the use of automatic and multicable devices, like Terrameter Ls, it is possible to perform different arrangements geometric tests in a shorter time and greater practicality, fact that support this work development. This dissertation presents the electrical tomography arrays comparative analysis to Schlumberger, Wenner, and Dipolo-Diplo, to verify the result that describes the most realistic expected deposit morphology, based in a hydrothermal magmatic metallogenetic deposit with high structural control. The comparative analysis revealed a conical body with high chargeability conformation (2,7 mV/V) that encompasses the high resistivity vertical core (438 Ω/m ), as well as an annular portion with high chargeability possibly correlated to the fault zone that structures the central and high block (volcanic tuff). The conical structure observed is compatible with the dike, vertical and cylindrical morphology described for hydr... (Complete abstract click electronic access below) / Mestre

The use of computed tomography (CT) in the care of patients has grown dramatically since its introduction over 30 years ago. The vast majority of the utilization research has focused on factors associated with the variable use in the outpatient and emergency department settings. This has left much of the inpatient use and variation understudied. This study has multiple aims. The first is to characterize the inpatient variation across multiple states and markets. The second is to evaluate the relationship between inpatient CT use and commercial payers across these areas. The third is to develop a model to evaluate the relationship between inpatient CT use and the characteristics of markets, hospitals, and patients. The study uses a four-state convenience sample of cross-sectional data for hospitals. It included non-Federal, acute care hospitals that reported the performance of inpatient CT exams during 2015 (N=181). The literature review was used to justify the inclusion of variables in the study. The descriptive analyses were used to justify the appropriateness of the variables and methodology for testing. A comparison of means demonstrated the significant differences for inpatient utilization between states. A univariate general linear model demonstrated a negative relationship with a hospital’s proportion of commercially insured patients and the inpatient utilization rate. An ordinary least squares multivariate linear regression was used to test for variable significance within each of three constructs: markets, hospitals, and patients. The results indicated that inpatient CT rates were positively associated with higher level of insurer concentration (market), positively associated with system centralization (hospitals), and negatively associated with a hospital’s increasing proportion of minority patient discharges (patients). The study serves an important function in identifying varying patterns of CT utilization across the full spectrum of inpatients across multiple states, regardless of payer. It also creates new knowledge about how the characteristics of these markets, hospitals, and patients are related to inpatient use. It also provides implications for administrators, researchers, and policy makers. The additional knowledge and understanding provided by this research have the potential to lead to improvements in the appropriate and equitable use of inpatient CT exams.

Papilledema is a particular type of optic disc swelling caused by elevated intracranial pressure. By observing the visible features from fundus images or direct funduscopic examination, a typical method of assessing papilledema (i.e., the six-stage Fris\'en grading system) is qualitative and frequently suffers from low reproducibility. Compared to fundus images, spectral-domain optical coherence tomography (SD-OCT) is a relatively new imaging technique and enables the cross-sectional information of the retina to be acquired. Using SD-OCT images, quantitative measurements like evaluating the retinal volume or depth are intuitively more robust than the traditional qualitative approach to evaluate papilledema. Also, multiple studies suggest that the deformation of the peripapillary retinal pigment epithelium and/or Bruch's membrane (pRPE/BM) may reflect the intracranial pressure change. In other words, modeling/quantifying the pRPE/BM shape can potentially be another indicator of papilledema. However, when the optic disc is severely swollen, the retinal structure is dramatically deformed and often causes the commercial SD-OCT devices to fail to segment the retinal layers. Without appropriate layer segmentation, all the retinal measurements are not reliable. To solve the current issue of inconsistently assessing papilledema severity, a comprehensive machine-learning framework is proposed in this doctoral work to achieve the goal by accomplishing following four aims. First, robust approaches are developed to automatically segment the retinal layers in 2D and 3D SD-OCT images, even though the optic discs can be severely swollen. Second, the semi- and fully automated methodologies are designed to segment the pRPE/BM opening under the swollen inner retina in these SD-OCT images. Third, the pRPE/BM shape models are constructed using both 2D and 3D SD-OCT images, and then the 2D/3D pRPE/BM shape measures are computed. Finally, based on the previously segmented retinal layers, eight OCT 2D/3D global/local measurements of retinal structure are reliably computed. Considering both the 2D/3D pRPE/BM shape measures and these eight OCT features as an input set, a machine-learning framework using the random forest technique is proposed to compute a papilledema severity score (PSS) on a continuous scale. The newly proposed PSS is expected to be an alternative to the traditional qualitative method to provide a more objective measurement of assessing papilledema severity.

Acquiring the motions of the inner ear sensory tissues provides insight to how the cochlea works. For this purpose, Spectral Domain Optical Coherence Tomography (SDOCT) is an ideal tool as it has a penetration depth of several millimeters. SDOCT can not only image inside the cochlear partition, but also measure the sample structures’ simultaneous displacements. We customized a commercial Spectral Domain Optical Coherence Tomography system for such functions and detailed the software and hardware steps so this powerful system could be more accessible to auditory researchers. The cochlea is surrounded by bones and tissues, and damage to it would make it passive. For this reason, cochlear vibrometry measuring locations have been limited to either the basal or apical regions. That is why I fabricated a two-dimensional scanning SDOCT-based probe, to access more cochlear locations through a small hand-drilled hole. What is exciting about the probe is that an electrode can be attached to its side to acquire spatially and temporally coincident voltage and displacement data. This would help us better understand the cochlear mechano-electrical feedback process. Lastly, I investigated how the SDPM-reported displacement could be influenced by its neighboring signals and demonstrated this signal competition phenomenon experimentally and theoretically.

No description available.

Master of Science in Dentistry / Objectives: The aims of this study were: • to evaluate the exact level of the mandibular canal using Cone Beam Volumetric Tomography (CBVT) using measurements taken on images from the NewTom3G and i-CAT machines and manually • to determine the course of the mandibular canal in the regions of the first, second , and third molars • to compare the course of the mandibular canals bilaterally • to compare variables measured between the CBVT and panoramic units • to determine appropriate positions for the implant placement at the region of the mandibular molars in relation to the mandibular canal. Methods: Ten mandibles were selected, including seven edentulous and three dentate ones. They were marked at four positions from the distal border of the mental foramina in the posterior direction at intervals of 10.00 mm. On each dry mandible, at four sites namely M0, M1, M2, and M3, Gutta Percha (GP) points, known as markers, were attached to the mandible so that they were parallel to the midline of the mandible on both buccal and lingual sides. On the NewTom 3G and i-CAT, variables of cross-sectional images were measured from the alveolar crest of the mandible to the superior border of the mandibular canal (AC); the lingual rim of the canal to the lingual margin of the mandible (LC); the buccal rim of the canal to the buccal margin of the mandible (BC); the inferior rim of the canal to the lower border of the mandible (IC), and from the lingual margin to the buccal margin of the mandible (BW: Bone Width). Dry mandibles were subsequently sacrificed by cutting at the four marked sites. On each cross-section of mandibles, distances AC, BC, LC, IC, and BW were measured using a caliper as the manual measurement. IC distances on a conventional OrthophosIII panoramic machine were also measured to compare with the CBVT. Data were managed by Microsoft Office Excel 2003 and transferred to the software of Statistics Package for Social Sciences (SPSS) version 15.0 for Windows for analysis. Data were presented as Mean, Standard Deviation (SD), and Mean Difference, and Standard Error of Mean (SEM) with decimal at 0.00. T-test and One-way ANOVA were used to analyse variables measured in which T-test was used to analyse variables with paired samples and One-way ANOVA was used with adjustment for multiple comparisons of Bonferroni. Statistical significance has an assumed P- value of 0.05 or less. Results: The findings showed that there was no significant difference among measured variables from the NewTom 3G, i-CAT and manual measurement (P>0.05). There was significant statistical difference between the Orthophos OPG machine and CBVT system (P=0.00<0.05). There was no significant difference in the course of the mandibular canals bilaterally (P>0.05). On average, Distances AC, BC, LC, and IC were obtained for reference purposes. The bone width of the mandible on the right side was slightly different from that on the left side. Conclusions: The findings implied CBVT was an accurate diagnostic tool for locating the course of the mandibular canal and for placing dental implants in the region of the mandibular molars. The course of the mandibular canal on the left and right sides was variable. The distances measured at the region of the first, second, and third mandibular molars should be considered as a valuable reference. The bone width of the mandible on the right and left sides was slightly different. The accuracy of the NewTom3G and i-CAT was superior to the panoramic Orthophos machine. However, a panoramic radiograph is still valuable in the daily dental clinic.

Machined fragments of 10 core plugs from oshore reservoirs have been analysed using a high resolution X-ray micro-computed tomography (micro-CT) facility. The facility includes a system capable of acquiring 3D images made up of 20003 voxels on core plugs up to 6 cm diameter with resolutions down to 2 um. The cores analysed include six cores from a gas reservoir and four cores from an oil reservoir. The cores exhibit a very broad range of pore and grain sizes, porosity, permeability and mineralogy. The petrological data, available only for gas reservoir cores, is compared with the data obtained from the tomographic images. Computational results made directly on the digitized tomographic images are presented for the permeability, formation factor, resistivity index and drainage capillary pressure across a range of . We show that data over a range of porosity can be computed from a single fragment. We compare the computations of petrophysical data on fragments to conventional laboratory measurements on the full plug. Permeability predictions from digital and conventional core analysis are consistent. It is shown that a characteristic length scale can be dened as a quality control parameter for the estimation of permeability. Results for formation factor, drainage capillary pressure and resistivity index are encouraging. The results demonstrate the potential to predict petrophysical properties from core material not suited for laboratory testing (e.g., sidewall or damaged core and drill cuttings) and the feasibility of combining digitized images with numerical calculations to predict properties and derive correlations for specic rock lithologies. The small sample size required for analysis makes it possible to produce multiple measurements on a single plug. This represents a potential multiplier on the quantity of core data allowing meaningful distributions or spreads in petrophysical properties to be estimated. We discuss the current limitations of the methodology and suggest improvements; in particular the need to calibrate the simulated data to parallel laboratory core measurements. We also describe the potential to extend the methodology to a wider range of petrophysical properties. This development could lead to a more systematic study of the assumptions, interpretations and analysis methods commonly applied within industry and lead to better correlations between petrophysical properties and log measurements.