Made available in DSpace on 2015-10-06T13:03:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-03. Added 1 bitstream(s) on 2015-10-06T13:18:56Z : No. of bitstreams: 1 000847380.pdf: 806327 bytes, checksum: f7d3032d99de2e92c79e98f58dfe233a (MD5) / Foi realizado estudo transversal, descritivo e observacional de 38 nervos ulnares de pacientes com hanseníase multibacilar, com idades entre 20 e 59 anos, com diagnóstico realizado na disciplina de dermatologia da Faculdade de Medicina de Botucatu (FMB-UNESP). Estes pacientes foram submetidos à palpação, exames de eletroneurografia e ultrassonografia dos nervos ulnares direito e esquerdo com o objetivo de estudar o comprometimento do nervo pela doença e comparar os resultados dos exames. Dos nervos estudados, nove (23,68%) não apresentaram nenhuma alteração nos resultados dos exames. Os que apresentaram alteração em um ou mais dos exames realizados, somaram 29 (76,32%). Os resultados foram comparados, e os que apresentaram alterações de normalidade em dois ou mais, foram denominados compatíveis. Houve compatibilidade de 20,68% entre clínica, eletroneurografia e ultrassonografia. Observou-se que esse fato ocorreu quando o exame ultrassonográfico mostrou valores próximos do dobro da normalidade. Não houve significância estatística entre os resultados apresentados; no entanto, deve-se considerar a correspondência entre os exames clínico, eletroneurográficos e ultrassonográficos / A cross-sectional, descriptive, observational study of 38 ulnar nerves of multibacillary patients, aged 20 to 59 years, with diagnosis made in Dermatology course of the Faculty of Medicine of Botucatu (FMB-UNESP). These patients underwent palpation, ultrasound exams and electroneurography ulnar nerve left and right in order to study the nerve disease involvement and compare the test results. The nerves studied, nine (23.68%) showed no change in the results of the examinations. Those who had alterations in one or more of the tests performed, totaled 29 (76.32%). The results were compared, and those with normal changes in two or more, were called compatible. There was 20.68% compatibility between clinical, electroneurography and ultrasound. It was observed that this actually occurred when the ultrasound examination showed values close to double the normal. There was no statistical significance between the results presented; however, one must consider the correlation between the clinical, electroneurographic and ultrasonography

M.Tech. / It is difficult to manage a pregnancy when fetal age, health status or potential pregnancy risks are not known. The aim of this study was to assess the impact of routine ultrasound screening as compared to selective use of ultrasound in the mid-trimester of pregnancy, on women using South African government health services. The three objectives investigated included assessment of the availability of reliable menstrual histories in the study population, the influence of ultrasound dating on obstetric management and the effect of ultrasound on pregnancy outcome due to the early detection of high risk pregnancies. A cluster randomised trial of 962 women was performed to test the hypothesis that midtrimester routine ultrasound screening in low risk pregnancies would result in improved antenatal care and perinatal outcome. Groups of eligible pregnant women were randomly selected to have either a routine scan followed by normal antenatal care or routine antenatal care which only allows for the selective use of ultrasound, in line with South African Antenatal Care Policy. Statistical analysis of the results confirmed that ultrasound dating is a more accurate predictor of the expected date of delivery when compared to other dating methods. Improved pregnancy dating resulted in a significant reduction in induction of labour for post-term pregnancy in the ultrasound screening group, suggesting a positive effect of ultrasound screening on obstetric management. No improvement was demonstrated in perinatal morbidity or mortality. The early detection of anomalous fetuses only led to one therapeutic abortion. The study did not possess the statistical power to demonstrate improved outcomes when multiple pregnancies were detected early in pregnancy. Currently there appears to be no urgent need to implement a routine antenatal screening programme in the Gauteng public health sector. In view of the fact that a third of the participants indicated that they were unsure of menstrual dates, and one third of the participants in the ultrasound screening group presented with an unreliable menstrual history, it is proposed that unsure dates be considered as a valid indication for the selective use of ultrasound in mid-trimester pregnancy.

Heart disease is the leading cause of death globally. Early diagnosis is the key to successful treatment. By providing noninvasive, non-ionizing, and real-time imaging, echocardiography plays a critical role in identifying heart disease. Compared to other imaging modalities, ultrasound has unparalleled temporal resolution. High frame-rate imaging has enabled the development of new metrics to characterize myocardial mechanics. Strain imaging measures the heart's deformation throughout the cardiac cycle, providing a quantitative assessment of cardiac health. The intention of this dissertation is to bring Myocardial Elastography (ME) closer to clinical realization. ME is a high frame-rate strain imaging technique for transthoracic and intracardiac echocardiography. This work consists of four Aims. There is a fundamental trade-off between spatial and temporal resolution in strain imaging. In Aim 1, the optimal transmit sequence that generates the most accurate and precise strain estimate was determined. Two common approaches to coherent compounding (full and partial aperture) were compared in simulation and in transthoracic imaging of healthy human subjects (n=5). The optimized subaperture compounding sequence (25-element subperture, 90° angular aperture, 10 virtual sources, 300 Hz frame rate) was compared to the optimized steered compounding sequence (60° angular aperture, 15° tilt, 10 virtual sources, 300 Hz frame rate) and was found to measure strain in healthy human subjects with equivalent precision. The optimal compounding configuration was then evaluated against two other high-frame rate transmit strategies, ECG-gated focused imaging, and wide-beam imaging, in simulation and in healthy subjects (n=7). Achieving the highest level of strain precision, ECG-gated focused imaging was determined to be the preferred imaging approach in patients capable of sustaining a breath hold, with compounding preferred in those unable to do so. Rapid diagnosis is essential to successful treatment of myocardial infarction. In Aim 2, ME's ability to track infarct formation and recovery, and localize infarct using regional strain measurments, was investigated in a large animal survival model (n=11). Infarcts were generated via ligation of the left anterior descending, imaging regularly for up to 28 days. A radial strain-based metric, percentage of healthy myocardium by strain (PHM_ε), was developed as a marker for healthy myocardial tissue. PHM_ε was strongly linearly correlated with actual infarct size as determined by gross pathology (R2 = 0.80). ME was capable of diagnosing individual myocardial segments as non-infarcted or infarcted with high sensitivity (82%), specificity (92%), and precision (85%) (ROC AUC = 0.90), and tracked infarct recovery from collateral reperfusion through time. Noninvasive strain imaging at rest can improve pre-test probability accuracy, and reduce unnecessary stress testing. In Aim 3, ME's potential to provide early diagnosis of coronary artery disease was investigated in an ongoing study. Patients undergoing myocardial perfusion imaging were recruited (n=126). Perfusion scores were used as the reference standard. Morphological transformations were integrated into the processing pipeline to reduce variability in the strain measurements. PHM_ε was reintroduced and used to differentiate between patients with and without coronary artery disease. ME was capable of distinguishing between normal patients and those with significant ischemia or infarct (subjects with perfusion defects at rest) with statistical significance (p < 0.05), although a greater sample size is needed to confirm the results. One of the most common treatments for arrhythmia, catheter ablation, can fail if the lesion line intended to terminate the abnormal rhythm is non-contiguous. In Aim 4, the gap resolution and clinical feasibility of Intracardiac Myocardial Elastography (IME) strain imaging, an ablation monitoring technique, was investigated. Lesion size estimation and gap resolution was evaluated in an open chest canine model (n=3), wherein lesion lines consisting of three lesions and two gaps were generated in each canine left ventricle via epicardial ablation. All gaps were resolvable. Average lesion and gap areas were measured with high agreement (33 ± 14 mm2 and 30 ± 15 mm2, respectively) when compared against gross pathology (34 ± 19 mm2 and 26 ± 11 mm2, respectively). Gaps as small as 11 mm2 (3.6 mm on epicardial surface) were identifiable. Patients undergoing ablation to treat typical cavotricuspid isthmus atrial flutter (n=5) were imaged throughout the procedure. In all patients, strain decreased in the cavotricuspid isthmus after ablation (mean paired difference of -17 ± 11 %, p < 0.05). Together, these Aims intend to translate a promising imaging method from research to clinical reality.

Diagnoses using images made with non-ionizing ultrasound are based on qualitive criteria and are not more accurate than those made with mammography. Information about tissue state is lost in the processing required to produce ultrasound images, and textural information may not be perceptible to a human observer. This study uses statistical pattern recognition to classify ultrasound A-scans, before any processing other than amplification occurs. A U. I. Octoson was used to collect data from normal, benign, and malignant, in vivo breast tissues. Features based on textural or frequency content of received sound were computed from digitized A-scans. Most textural features have been used previously in image processing, while frequency features assumed differences in frequency-dependent attenuation. Data were collected at the University of Arizona from 17 malignant masses, 8 benign masses, and 7 normal tissues. Univariate and multivariate statistical tests were used to find combinations of features which discriminated best between the classes of tissue. Equal a priori probabilities were used in a Bayesian classifier to classify malignant vs. nonmalignant. Specificity of 76% (13 of 17 malignant masses correct) was found with a sensitivity of 80% (12 of 15 masses correct). A linear combination of one frequency feature and three textural features was used. For malignant vs. benign, sensitivity of 88% (15 of 17 masses) and specificity of 75% (6 of 8 masses) were found. Features used were the same as for classification of malignant vs. nonmalignant, except for modification of one textural feature. The inability to visually detect and gather data from some palpable masses means that further study is needed to determine the effectiveness of applying the method to all breast masses. A set of A-scans from Thomas Jefferson Hospital in Philadelphia was gathered using similar procedures, and analysed with the following results: 18 of 21 (86%) malignant masses, and 45 of 66 (68%) nonmalignant masses were classified correctly, using a linear combination of one textural feature and five frequency features. Confidence limits on the results show that the majority of masses can be classified correctly with this procedure, but success rates are not high enough for breast cancer screening.

Recent studies have indicated that vascular stiffness is an important predictor of future cardiovascular disease. Hence, assessment of vascular stiffness would be of interest. Ultrasound is a good modality for assessment of vascular stiffness, due to its hight temporal resolution and non-invasive nature. Using ultrasound, various techniques have been proposedto estimate vascular stiffness, one of them being Pulse Wave Imaging. The ultimate goal of Pulse Wave Imaging is to provide a robust, qualitative and quantitative method to estimate and visualize clinically important parameters and phenomenonfor cardiovascular disease. The objective of this thesis limits itself to 1) expand Pulse Wave Imaging by going beyond just the diastolic stiffness, 2) utilize Pulse Wave Imaging in an atherosclerotic swine model to monitor plaque initiation and progression and 3) improve non-linear stiffness estimation at or near sites of reflections using Pulse Wave Imaging for clinical applications. In Aim 1, the question pursued was whether Pulse Wave Imaging can be utilized to monitor this non-linear behavior in-vivo. It was observed that in this mouse model, the compliance at diastolic pressure did not change significantly, whereas the compliance at end-systole did. Thus suggesting that Pulse Wave Imaging was able to monitor a change in non-linear stiffness, and that considering this, might be of importance. In Aim 2, the ability of Pulse Wave Imaging to monitor disease progression for atherosclerotic disease progression was assessed. Since human studies involve various compounding factors, animal models provide the opportunity to study the ability of methods in a more controlled manner. Swine is a good candidate due to its similarity with humans. To doso, first, the feasibility of Pulse Wave Imaging in swine needed to be assessed. While the cardiovascular system might be similar, various other factors, such as the location and depth of the carotid differs. It was revealed that PWI was feasible in swine and that we were able to generate atherosclerotic lesions within 9-months. Subsequently the ability of Pulse Wave Imaging and Vector Flow Imaging to monitor atherosclerotic progression leading to different type of lesions was assessed. The in-vivo findings were compared with histology and nanoidentation. The results indicated that Pulse Wave Imaging was shown to be able to separate to different disease progression pathways leading to different type of lesions. Finally in Aim 3, lessons learned from the animal models were attempted to be addressed by developing a more reflection robust approach for localized non-linear stiffness estimation for clinical application. First, improvements were proposed to a previously developed inverse problem approach that can resolve reflections within the field of view by including information from the flow velocity. To expand the approach to include non-linearity and reflections that occur outside the field of view, a physics-based neural network approach was considered. This might be of importance since most plaques are located at sites of significant reflections, such as the bifurcation. Chapter 6 revealed that artificial significant sources of reflections hindered its ability for sub-cm scale localized compliance measurements as indicated by an immediate increase in the number of detected segments after the ligation was induced. The approaches was validated using simulated data and feasibility was shown in in-vivo examples. With new progress, new issues tend to arise. Finally, the purpose of this sub-aim is to utilize the technique and investigate whether or not it can in fact better differentiate between different clinically relevant groups. The findings revealed no significant improvement concerning the mean compliance estimated, but appeared more robust against outliers when only the plaque segment was assessed. In conclusion, the results shown in this dissertation indicate that Pulse Wave Imaging is a promising approach to assess non-linear stiffness estimation for monitoring of vascular disease. Furthermore, an new methodology was proposed and feasibility was shown, which could further improve localized and non-linear stiffness estimation at or near sources of significant reflections, and which can be used as a starting point for further development.

No description available.

published_or_final_version / abstract / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

published_or_final_version / Obstetrics and Gynaecology / Master / Master of Philosophy

Orientador: Maria Emilia Franco Oliveira / Coorientador: Fabio Morato Monteiro / Coorientador: Vera Fernanda Martins Hossepian de Lima / Banca: Letícia Zoccolaro Oliveira / Banca: Lindsay Unno Gimenes / Resumo: O exame andrológico em bovinos reprodutores é de extrema importância para identificação da capacidade reprodutiva de touros. A ultrassonografia é uma ferramenta diagnóstica que pode fornecer importantes informações de forma não invasiva da integridade dos órgãos reprodutivos, no entanto, ainda vem sendo pouco aplicada na prática de avaliação de reprodutores. O objetivo do trabalho foi caracterizar e comparar parâmetros biométricos e atributos ultrassonográficos de testículos, epidídimos e glândulas genitais acessórias, bem como, índices vasculares das artérias testiculares e ilíacas internas de touros das raças Nelore (n=203) e Caracu (n=79), agrupados de acordo com as classes de idade (≤ 18 meses e > 18 meses). Os dados foram analisados pelo PROC MIXED do programa SAS (p<0,05). O perímetro escrotal, comprimento testicular e medida dorsoventral da cauda do epidídimo foram diferentes entre animais ≤ 18 meses e > 18 meses nas raças Nelore e Caracu. A biometria das glândulas vesiculares, porção disseminada da próstata e medida craniocaudal da glândula bulbouretral apresentaram diferença entre raças. Houve diferença entre as idades para glândulas vesiculares, medidas dorsoventral e craniocaudal do corpo da próstata e próstata disseminada. Houve correlações significativas (p<0,05) entre a biometria dos testículos, cauda dos epidídimos e glândulas genitais acessórias, exceto com o corpo da próstata. A intensidade de pixel do parênquima testicular diferiu entre raças e classes de id... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The andrological examination in breeding cattle is of extreme importance for the identification of the reproductive capacity of bulls. Ultrasonography is a diagnostic tool that can provide important noninvasive information on the integrity of reproductive organs, however, it still has been little applied in practice of reproductive evaluation. The objective of this study was to characterize and compare biometric parameters and ultrasonographic attributes of the testes, epididymis and accessory sex glands, as well as vascular indices of internal testes and iliac arteries of Nellore (n=203) and Caracu bulls (n=79), grouped according to age classes (≤18 months and >18 months). Data were analyzed by PROC MIXED of SAS program (p<0.05). The scrotal perimeter, testicular length and dorsoventral measurement of the tail of the epididymis were different between animals ≤18 months and >18 months in the Nellore and Caracu races. The biometry of vesicular glands, disseminated portion of prostate and craniocaudal measurement of bulbourethral gland showed differences between breeds. Were differences between ages for vesicular glands, dorsoventral and craniocaudal measurements of prostate body and disseminated prostate. Were significant correlations (p<0.05) between the biometry of the testes, tail of the epididymides and accessory sex glands, except with the body of the prostate. The pixel intensity of the testicular parenchyma differed between breeds and age classes. The echogenicity (mea... (Complete abstract click electronic access below) / Mestre

Three dimensional (3D) ultrasound has become an increasingly popular medical imaging tool over the last decade. It offers significant advantages over Two Dimensional (2D) ultrasound, such as improved accuracy, the ability to display image planes that are physically impossible with 2D ultrasound, and reduced dependence on the skill of the sonographer. Among 3D medical imaging techniques, ultrasound is the only one portable enough to be used by first responders, on the battlefield, and in rural areas. There are three basic methods of acquiring 3D ultrasound images. In the first method, a 2D array transducer is used to capture a 3D volume directly, using electronic beam steering. This method is mainly used for echocardiography. In the second method, a linear array transducer is mechanically actuated, giving a slower and less expensive alternative to the 2D array. The third method uses a linear array transducer that is moved by hand. This method is known as freehand 3D ultrasound. Whether using a 2D array or a mechanically actuated linear array transducer, the position and orientation of each image is known ahead of time. This is not the case for freehand scanning. To reconstruct a 3D volume from a series of 2D ultrasound images, assumptions must be made about the position and orientation of each image, or a mechanism for detecting the position and orientation of each image must be employed. The most widely used method for freehand 3D imaging relies on the assumption that the probe moves along a straight path with constant orientation and speed. This method requires considerable skill on the part of the sonographer. Another technique uses features within the images themselves to form an estimate of each image's relative location. However, these techniques are not well accepted for diagnostic use because they are not always reliable. The final method for acquiring position and orientation information is to use a six Degree-of-Freedom (6 DoF) tracking system. Commercially available 6 DoF tracking systems use magnetic fields, ultrasonic ranging, or optical tracking to measure the position and orientation of a target. Although accurate, all of these systems have fundamental limitations in that they are relatively expensive and they all require sensors or transmitters to be placed in fixed locations to provide a fixed frame of reference. The goal of the work presented here is to create a probe tracking system for freehand 3D ultrasound that does not rely on any fixed frame of reference. This system tracks the ultrasound probe using only sensors integrated into the probe itself. The advantages of such a system are that it requires no setup before it can be used, it is more portable because no extra equipment is required, it is immune from environmental interference, and it is less expensive than external tracking systems. An ideal tracking system for freehand 3D ultrasound would track in all 6 DoF. However, current sensor technology limits this system to five. Linear transducer motion along the skin surface is tracked optically and transducer orientation is tracked using MEMS gyroscopes. An optical tracking system was developed around an optical mouse sensor to provide linear position information by tracking the skin surface. Two versions were evaluated. One included an optical fiber bundle and the other did not. The purpose of the optical fiber is to allow the system to integrate more easily into existing probes by allowing the sensor and electronics to be mounted away from the scanning end of the probe. Each version was optimized to track features on the skin surface while providing adequate Depth Of Field (DOF) to accept variation in the height of the skin surface. Orientation information is acquired using a 3 axis MEMS gyroscope. The sensor was thoroughly characterized to quantify performance in terms of accuracy and drift. This data provided a basis for estimating the achievable 3D reconstruction accuracy of the complete system. Electrical and mechanical components were designed to attach the sensor to the ultrasound probe in such a way as to simulate its being embedded in the probe itself. An embedded system was developed to perform the processing necessary to translate the sensor data into probe position and orientation estimates in real time. The system utilizes a Microblaze soft core microprocessor and a set of peripheral devices implemented in a Xilinx Spartan 3E field programmable gate array. The Xilinx Microkernel real time operating system performs essential system management tasks and provides a stable software platform for implementation of the inertial tracking algorithm. Stradwin 3D ultrasound software was used to provide a user interface and perform the actual 3D volume reconstruction. Stradwin retrieves 2D ultrasound images from the Terason t3000 portable ultrasound system and communicates with the tracking system to gather position and orientation data. The 3D reconstruction is generated and displayed on the screen of the PC in real time. Stradwin also provides essential system features such as storage and retrieval of data, 3D data interaction, reslicing, manual 3D segmentation, and volume calculation for segmented regions. The 3D reconstruction performance of the system was evaluated by freehand scanning a cylindrical inclusion in a CIRS model 044 ultrasound phantom. Five different motion profiles were used and each profile was repeated 10 times. This entire test regimen was performed twice, once with the optical tracking system using the optical fiber bundle, and once with the optical tracking system without the optical fiber bundle. 3D reconstructions were performed with and without the position and orientation data to provide a basis for comparison. Volume error and surface error were used as the performance metrics. Volume error ranged from 1.3% to 5.3% with tracking information versus 15.6% to 21.9% without for the version of the system without the optical fiber bundle. Volume error ranged from 3.7% to 7.6% with tracking information versus 8.7% to 13.7% without for the version of the system with the optical fiber bundle. Surface error ranged from 0.319 mm RMS to 0.462 mm RMS with tracking information versus 0.678 mm RMS to 1.261 mm RMS without for the version of the system without the optical fiber bundle. Surface error ranged from 0.326 mm RMS to 0.774 mm RMS with tracking information versus 0.538 mm RMS to 1.657 mm RMS without for the version of the system with the optical fiber bundle. The prototype tracking system successfully demonstrated that accurate 3D ultrasound volumes can be generated from 2D freehand data using only sensors integrated into the ultrasound probe. One serious shortcoming of this system is that it only tracks 5 of the 6 degrees of freedom required to perform complete 3D reconstructions. The optical system provides information about linear movement but because it tracks a surface, it cannot measure vertical displacement. Overcoming this limitation is the most obvious candidate for future research using this system. The overall tracking platform, meaning the embedded tracking computer and the PC software, developed and integrated in this work, is ready to take advantage of vertical displacement data, should a method be developed for sensing it.