Ma, Ka Lim. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves [110]-117). / Abstracts in English and Chinese. / Chapter 1 --- Radon Transform and Medical Tomography --- p.1 / Chapter 1.1 --- Computed Tomography --- p.2 / Chapter 1.2 --- Emission Computed Tomography --- p.4 / Chapter 1.2.1 --- SPECT --- p.5 / Chapter 1.2.2 --- PET --- p.6 / Chapter 1.3 --- Radon Transform --- p.8 / Chapter 1.3.1 --- Properties of Radon Transform --- p.10 / Chapter 1.3.2 --- Fourier Slice Theorem --- p.11 / Chapter 1.4 --- Research Objective --- p.12 / Chapter 2 --- Popular Tomographic Reconstruction Algorithms --- p.14 / Chapter 2.1 --- Analytic Method --- p.15 / Chapter 2.1.1 --- Direct Fourier Method (DFM) --- p.15 / Chapter 2.1.2 --- Backprojection (BP) --- p.17 / Chapter 2.1.3 --- Backprojection Filtering (BPF) --- p.19 / Chapter 2.1.4 --- Filtered Backprojection (FBP) --- p.21 / Chapter 2.2 --- Iterative Method --- p.23 / Chapter 2.2.1 --- Maximum Likelihood - Expectation Maximization (ML-EM) --- p.25 / Chapter 2.2.2 --- Ordered Subsets Expectation Maximization (OSEM) --- p.27 / Chapter 3 --- Consistent Reconstruction --- p.30 / Chapter 3.1 --- Directional Filter Bank (DFB) --- p.30 / Chapter 3.1.1 --- Interpolation in horizontal function space --- p.32 / Chapter 3.1.2 --- Directional Multiresolution Analysis --- p.33 / Chapter 3.1.3 --- Iterated Filter Bank Equivalence --- p.36 / Chapter 3.1.4 --- Vertical Directional Function Space --- p.38 / Chapter 3.1.5 --- Summary --- p.40 / Chapter 3.2 --- Reconstruction Scheme --- p.42 / Chapter 3.2.1 --- Choices for basis function 6m --- p.43 / Chapter 3.2.2 --- Choices for coordinate mapping function wm --- p.46 / Chapter 3.2.3 --- Summary --- p.49 / Chapter 3.3 --- Experiment --- p.49 / Chapter 3.3.1 --- Experiment for consistent reconstruction with different choices --- p.50 / Chapter 3.3.2 --- Experiment for comparison with different reconstruction methods --- p.54 / Chapter 3.4 --- Conclusion --- p.56 / Chapter 4 --- Tomographic Denoising --- p.57 / Chapter 4.1 --- SURE-LET and PURE-LET denoising --- p.59 / Chapter 4.1.1 --- SURE-LET --- p.60 / Chapter 4.1.2 --- PURE-LET --- p.62 / Chapter 4.2 --- Experiment --- p.64 / Chapter 4.2.1 --- Experiment on SURE-LET Denoising --- p.65 / Chapter 4.2.2 --- Experiment on PURE-LET Denoising --- p.69 / Chapter 4.2.3 --- Conclusion --- p.76 / Chapter 5 --- Sinogram Retrieval --- p.77 / Chapter 5.1 --- Sinogram Retrieval Method --- p.78 / Chapter 5.1.1 --- MATLAB Radon Function --- p.79 / Chapter 5.1.2 --- Subordinate Gradient (SG) Algorithm --- p.81 / Chapter 5.1.3 --- Orthonormal Subordinate Gradient (OSG) Algorithm --- p.81 / Chapter 5.2 --- Experiment --- p.84 / Chapter 5.2.1 --- Limitation of Sinogram Retrieval --- p.84 / Chapter 5.2.2 --- Comparison of Sinogram Retrieval Algorithms --- p.86 / Chapter 5.2.3 --- Embedded in Tomographic Reconstruction --- p.88 / Chapter 5.2.4 --- Embedded in Tomographic Denoising --- p.90 / Chapter 5.3 --- Conclusion --- p.96 / Chapter 6 --- Conclusion --- p.97 / Chapter 6.1 --- Summary --- p.97 / Chapter 6.1.1 --- Tomographic Reconstruction --- p.97 / Chapter 6.1.2 --- Tomographic Denoising --- p.98 / Chapter 6.1.3 --- Sinogram Retrieval --- p.98 / Chapter 6.2 --- Future Research --- p.99 / Chapter 6.2.1 --- Tomographic Reconstruction --- p.99 / Chapter 6.2.2 --- Tomographic Denoising --- p.99 / Chapter 6.2.3 --- Sinogram Retrieval --- p.99 / Chapter A --- Examples of Radon Transform --- p.100 / Chapter B --- Experimental Phantom Image --- p.104 / Chapter C --- Results of sinogram retrieval experiments --- p.107 / Bibliography --- p.110

INTRODUÇÃO: O plexo braquial é uma rede de estruturas nervosas responsáveis pela inervação motora e sensitiva do membro superior. Os métodos por imagem são de importância fundamental para a complementação diagnóstica tanto na localização como na caracterização do tipo de lesão que acomete o plexo braquial. O objetivo deste trabalho foi avaliar a eficácia do exame de ultrassonografia (US) na visualização do plexo e avaliar o método comparativamente à ressonância magnética (RM). MATERIAL E MÉTODOS: Este é um trabalho prospectivo comparativo entre US e RM na avaliação da anatomia do plexo braquial direito e esquerdo de 20 voluntários normais, totalizando 40 plexos braquiais. Os exames foram realizados no Instituto de Radiologia - Hospital das Clínicas da Faculdade de Medicina da USP. O grupo estudado foi constituído por 10 homens e 10 mulheres, com idades entre 33 e 68 anos (mediana = 42,5 anos, média = 47,2 anos). O estudo de US foi realizado utilizando transdutor linear multifrequencial (13-5 mHz) e o de RM com equipamento em alto campo magnético (1,5 T), utilizando bobina de superfície. O plexo braquial foi dividido em segmentos para estimar a frequência de visualização de cada um em ambos os métodos de diagnóstico por imagem: 1) foraminal (raízes nervosas), 2) espaço interescaleno (junção das raízes nervosas até a formação dos troncos); 3) espaço costoclavicular, correspondendo à região supra e infraclaviculares (troncos e divisões anterior e posterior, cordas); 4) espaço retropeitoral menor (cordas). RESULTADOS: As raízes cervicais juntamente com os troncos superior e médio foram as estruturas que apresentaram maior grau de visualização pelo US. Na RM a maioria das estruturas, com exceção das divisões do plexo, apresentaram excelente grau de visualização. Na análise de equivalência entre os observadores de US e RM, as raízes cervicais de C6, C7 e o tronco médio bilateral apresentaram grau de visualização equivalentes com alta concordância. Nos demais segmentos não houve equivalência na visualização entre os observadores, atentando para menor visualização pelo observador do US. CONCLUSÃO: O método de US consegue avaliar de forma eficaz o segmento proximal do plexo braquial que compreende as saídas das raízes cervicais de C5, C6 e C7, assim como os troncos superior e médio na região lateral do pescoço. O método não é adequado para visualizar as raízes de T1, as divisões anterior e posterior e consegue avaliar de forma parcial e limitada as raízes de C8, tronco inferior e as cordas medial, lateral e posterior do plexo braquial nos espaços costoclavicular e retropeitoral menor / INTRODUCTION: The brachial plexus is a network of neural structures responsible for sensory and motor innervation of the upper limb. The imaging methods are of fundamental importance for diagnostic reasons both in location and in the characterization of the lesion affecting the brachial plexus. The aim of this study was to assess the degree of effectiveness of the ultrasound examination in view of the segments of brachial plexus and assess the value of the method compared to MRI. MATERIAL AND METHODS: This is a prospective study of comparison between US and MRI, studying the anatomy of the right and left sides of brachial plexus in 20 volunteers, totaling 40 plexuses. The exams were performed in the Institute of Radiology - Hospital das Clínicas University of São Paulo Medical School (FMUSP). The study group consisted of 10 men and 10 women, aged 33-68 years (median = 42.5 years, mean = 47.2 years). The U.S. study was performed using a multifrequency linear transducer (13-5 MHz) and MRI equipment in high magnetic field (1.5 T) using a surface coil. The brachial plexus was divided into segments to estimate the frequency of visualization and comparison with MRI: 1) foramen (nerve roots), 2) interscalene space (junction of the nerve roots to the formation of the trunks) 3) costoclavicular space, corresponding to supra and infra-clavicular (trunks and anterior and posterior divisions, cords), 4) retropectoralis minor space (cords). RESULTS: The cervical roots along with the superior and middle trunks were the structures that showed better visualization degree by the US. On MRI, most structures, except for the anterior and posterior divisions of plexus, showed excellent visualization degree. In the analysis of equivalence between the US and MRI of the cervical roots C6, C7 and bilateral upper and middle trunk showed equivalent degree of visualization. In other segments there was equivalence in view among observers, always towards lower viewing by the observer from the US. CONCLUSION: US can effectively assess the proximal segment of the brachial plexus comprising outlet cervical roots C5, C6 and C7, as well as the upper and middle trunk in the lateral neck and partial and limited visualization of other brachial plexus segments in the costo-clavicular and retropectoralis minor spaces

INTRODUÇÃO: O plexo braquial é uma rede de estruturas nervosas responsáveis pela inervação motora e sensitiva do membro superior. Os métodos por imagem são de importância fundamental para a complementação diagnóstica tanto na localização como na caracterização do tipo de lesão que acomete o plexo braquial. O objetivo deste trabalho foi avaliar a eficácia do exame de ultrassonografia (US) na visualização do plexo e avaliar o método comparativamente à ressonância magnética (RM). MATERIAL E MÉTODOS: Este é um trabalho prospectivo comparativo entre US e RM na avaliação da anatomia do plexo braquial direito e esquerdo de 20 voluntários normais, totalizando 40 plexos braquiais. Os exames foram realizados no Instituto de Radiologia - Hospital das Clínicas da Faculdade de Medicina da USP. O grupo estudado foi constituído por 10 homens e 10 mulheres, com idades entre 33 e 68 anos (mediana = 42,5 anos, média = 47,2 anos). O estudo de US foi realizado utilizando transdutor linear multifrequencial (13-5 mHz) e o de RM com equipamento em alto campo magnético (1,5 T), utilizando bobina de superfície. O plexo braquial foi dividido em segmentos para estimar a frequência de visualização de cada um em ambos os métodos de diagnóstico por imagem: 1) foraminal (raízes nervosas), 2) espaço interescaleno (junção das raízes nervosas até a formação dos troncos); 3) espaço costoclavicular, correspondendo à região supra e infraclaviculares (troncos e divisões anterior e posterior, cordas); 4) espaço retropeitoral menor (cordas). RESULTADOS: As raízes cervicais juntamente com os troncos superior e médio foram as estruturas que apresentaram maior grau de visualização pelo US. Na RM a maioria das estruturas, com exceção das divisões do plexo, apresentaram excelente grau de visualização. Na análise de equivalência entre os observadores de US e RM, as raízes cervicais de C6, C7 e o tronco médio bilateral apresentaram grau de visualização equivalentes com alta concordância. Nos demais segmentos não houve equivalência na visualização entre os observadores, atentando para menor visualização pelo observador do US. CONCLUSÃO: O método de US consegue avaliar de forma eficaz o segmento proximal do plexo braquial que compreende as saídas das raízes cervicais de C5, C6 e C7, assim como os troncos superior e médio na região lateral do pescoço. O método não é adequado para visualizar as raízes de T1, as divisões anterior e posterior e consegue avaliar de forma parcial e limitada as raízes de C8, tronco inferior e as cordas medial, lateral e posterior do plexo braquial nos espaços costoclavicular e retropeitoral menor / INTRODUCTION: The brachial plexus is a network of neural structures responsible for sensory and motor innervation of the upper limb. The imaging methods are of fundamental importance for diagnostic reasons both in location and in the characterization of the lesion affecting the brachial plexus. The aim of this study was to assess the degree of effectiveness of the ultrasound examination in view of the segments of brachial plexus and assess the value of the method compared to MRI. MATERIAL AND METHODS: This is a prospective study of comparison between US and MRI, studying the anatomy of the right and left sides of brachial plexus in 20 volunteers, totaling 40 plexuses. The exams were performed in the Institute of Radiology - Hospital das Clínicas University of São Paulo Medical School (FMUSP). The study group consisted of 10 men and 10 women, aged 33-68 years (median = 42.5 years, mean = 47.2 years). The U.S. study was performed using a multifrequency linear transducer (13-5 MHz) and MRI equipment in high magnetic field (1.5 T) using a surface coil. The brachial plexus was divided into segments to estimate the frequency of visualization and comparison with MRI: 1) foramen (nerve roots), 2) interscalene space (junction of the nerve roots to the formation of the trunks) 3) costoclavicular space, corresponding to supra and infra-clavicular (trunks and anterior and posterior divisions, cords), 4) retropectoralis minor space (cords). RESULTS: The cervical roots along with the superior and middle trunks were the structures that showed better visualization degree by the US. On MRI, most structures, except for the anterior and posterior divisions of plexus, showed excellent visualization degree. In the analysis of equivalence between the US and MRI of the cervical roots C6, C7 and bilateral upper and middle trunk showed equivalent degree of visualization. In other segments there was equivalence in view among observers, always towards lower viewing by the observer from the US. CONCLUSION: US can effectively assess the proximal segment of the brachial plexus comprising outlet cervical roots C5, C6 and C7, as well as the upper and middle trunk in the lateral neck and partial and limited visualization of other brachial plexus segments in the costo-clavicular and retropectoralis minor spaces