Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 88-100).

Thesis--Lund Institute of Technology, 1994. / Added t.p. with thesis statement inserted.

Thesis--Lund Institute of Technology, 1994. / Added t.p. with thesis statement inserted.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.

Gao Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 191-194). / Abstracts in English and Chinese. / Abstract in English --- p.i / Abstract in Chinese --- p.iii / Acknowledgement --- p.v / Introduction --- p.vi / Contents --- p.viii / List of tables --- p.xiv / List of figures --- p.xv / Chapter Chapter One --- Literature Review / Chapter 1.1 --- Middle Cerebral Artery (MCA) Stenos --- p.is / Chapter 1.1.1 --- Prevalence of atherosclerotic MCA stenosis --- p.2 / Chapter 1.1.2 --- Methods for diagnosis of MCA stenosis --- p.3 / Chapter 1.1.3 --- Possible mechanism and course of stroke with MCA stenosis --- p.4 / Chapter 1.1.4 --- Treatment and prevention of stroke in patients with MCA stenosis --- p.5 / Chapter 1.2 --- Microembolic Signal (MES) Detection / Chapter 1.2.1 --- Introduction --- p.9 / Chapter 1.2.2 --- Technology --- p.9 / Characteristics of MES / Factors that affect MES detection / Problems of technology / Chapter 1.2.3 --- Clinical application --- p.15 / MES originating from atherosclerotic carotid artery stenosis / MES detection in internal carotid endarterectomy (CEA) / MES detection in patients with MCA stenosis / Predicting value and application in therapeutic trial / References --- p.19 / Chapter Chapter Two --- General Methodology / Chapter 2.1 --- Transcranial Doppler (TCD) Diagnosis for Intracranial Artery Stenosis / Chapter 2.1.1 --- TCD spectrum and common parameters --- p.29 / Chapter 2.1.2 --- Emitting and receiving transducers --- p.29 / Chapter 2.1.3 --- Pulsitility index (PI) --- p.31 / Chapter 2.1.4 --- Insonation depth and flow direction --- p.31 / Chapter 2.1.5 --- Continuous wave (CW) and pulsed wave (PW) --- p.33 / Chapter 2.1.6 --- Normal intracranial arteries through temporal and suboccipital window --- p.33 / Chapter 2.1.7 --- Normal intracranial arteries through orbital window --- p.36 / Chapter 2.1.8 --- Normal extracranial arteries --- p.36 / Chapter 2.1.9 --- TCD diagnosis for intracranial artery stenosis --- p.39 / Chapter 2.1.10 --- Example of multiple intracranial arteries stenosis --- p.39 / Chapter 2.2 --- Microembolic Signal (MES) Detection / Chapter 2.2.1 --- Device of MES monitoring --- p.41 / Chapter 2.2.2 --- Insonated artery and depth --- p.41 / Chapter 2.2.3 --- Axis length of the sample volume --- p.43 / Chapter 2.2.4 --- Fast Fourier Transform (FFT) time window overlap --- p.43 / Chapter 2.2.5 --- Distinguishing embolic signal and artifact with two-gate transducer --- p.45 / Chapter 2.2.6 --- Measurements of embolic signal and threshold --- p.47 / References --- p.45 / Chapter Chapter Three --- Prevalence and Clinical Significance of Microembolic Signal (MES) in Patients with Middle Cerebral Artery (MCA) Stenosis / Chapter 3.1 --- Abstract --- p.50 / Chapter 3.2 --- Introduction --- p.51 / Chapter 3.3 --- Methodology --- p.51 / Patients / Severity of stroke and clinical course / Diagnosis for middle cerebral artery (MCA) stenosis / Microembolic signal (MES) detection / Statistical analysis / Chapter 3.4 --- Results --- p.55 / Baseline information of patients / Prevalence of MES / Relationship between presence of MES and severity of MCA stenosis / Correlation between presence of MES and clinical course in 85 symptomatic patients / Correlation between the count of MES and clinical course in 85 symptomatic patients / Correlation between the presence of MES and further ischemic stroke / Chapter 3.5 --- Discussion --- p.63 / Prevalence of MES / Association between severity of stroke and presence or the number of MES / Predictive value of MES for further stroke / References --- p.66 / Chapter Chapter Four --- Mechanisms of Acute Cerebral Infarction in Patients with Cerebral Artery Stenosis: a Diffusion-weighted Imaging and Microemboli Monitoring study / Chapter 4.1 --- Abstract / Chapter 4.2 --- Introduction --- p.72 / Chapter 4.3 --- Methodology --- p.73 / Patients / Microembolic signal (MES) detection by transcranial Doppler (TCD) / "Magnetic resonance imaging (DWI, MRI and MRA)" / Statistical analysis / Chapter 4.4 --- Results --- p.77 / Severity of MCA stenosis on MRA and pattern of infarct on DWI / Frequency and count of MES and its relationship with multiple and borderzone infarction on DWI / Chapter 4.5 --- Discussion --- p.79 / Frequency of MES / Pattern of cerebral infarcts on DWI / Relationship between MES and multiple infarcts on DWI / References --- p.83 / Chapter Chapter Five / Chapter Chapter Five-I --- Novel Observations of the Characteristics of Real Time Genesis of Thromboembolism in Middle Cerebral Artery Stenosis Detected by Transcranial Doppler / Chapter 5.1.1 --- Abstract --- p.90 / Chapter 5.1.2 --- Introduction --- p.91 / Chapter 5.1.3 --- Methodology --- p.91 / Characteristics of patients / "MRA, DWI and conventional TCD data" / MES monitoring method and overall data / Neuroimaging and MES monitoring data in all five patients / Signal analysis in off-line / Confirmation test for the origin of MES / Chapter 5.1.4 --- Results --- p.104 / Frequency of three special phenomena / Characteristics of three special phenomena / Results of confirmation test for embolic source / Chapter 5.1.5 --- Discussion --- p.133 / Occurrence of MES with flow velocity change simultaneously / MES splatter / Bi-directional low frequency (S-velocity) vibration / Testing for source of MES detected from MCA stenosis / References --- p.139 / Chapter Chapter Five-II --- Characteristics of Microembolic Signals Detected near Its Origin from the Middle Cerebral Artery Stenosis / Chapter 5.2.1 --- Abstract --- p.143 / Chapter 5.2.2 --- Introduction --- p.144 / Chapter 5.2.3 --- Methodology --- p.144 / Patients / Microembolic signal (MES) detection / Classification of MES / Chapter 5.2.4 --- Results --- p.145 / Types of MES detected from MCA stenosis / Characteristics of three types of MES / Chapter 5.2.5 --- Discussion --- p.157 / Emboli moving from vessel wall to the center / Emboli vibration / About calculating the time delay between two channels / References --- p.160 / Chapter Chapter Five-III --- "Hemodynamic change,microembolic signal counts and use of antithrombotic treatments" / Chapter 5.3.1 --- Abstract --- p.163 / Chapter 5.3.2 --- Introduction --- p.164 / Chapter 5.3.3 --- Methodology --- p.164 / Chapter 5.3.4 --- Results / "The relationship among flow velocity, the number of MES and time since symptom onset" --- p.165 / Patient one / Patient two / Patient three / Chapter 5.3.5 --- Discussion / Association between flow velocity or MES change and different anticoagulants in acute stage / Progression of MCA stenosis after acute stage / Stability of MCA atherosclerotic stenosis / References --- p.173 / Chapter Chapter Six --- The Optimal Values of Flow Velocity on Transcranial Dopplerin Grading Severity of Middle Cerebral Artery Stenosis in Comparison With Magnetic Resonance Angiography / Chapter 6.1 --- Abstract --- p.179 / Chapter 6.2 --- Introduction --- p.180 / Chapter 6.3 --- Methodology --- p.180 / Patients / TCD examination / Grading of MCA stenosis on MRA / Statistical analysis / Chapter 6.4 --- Results --- p.182 / Detection of >50% MCA stenosis according to flow velocity / Grading severity of MCA stenosis by flow velocity / Chapter 6.5 --- Discussion --- p.186 / Reliability of TCD diagnosis for MCA stenosis / Grading MCA stenosis according to flow velocity on TCD / References / Abbreviations --- p.189 / Publications --- p.191

by Young Lee Kei, Ricky. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 205-207). / Abstract also in Chinese. / Acknowledgements --- p.i / Statement of Originality --- p.ii / Abstract --- p.iii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Anatomy of liver --- p.1 / Chapter 1.2 --- Anatomical Implications --- p.16 / Chapter Chapter 2 --- Background / Chapter 2.1 --- Common focal hepatic lesions --- p.21 / Chapter 2.2 --- Imaging techniques --- p.28 / Chapter 2.3 --- Characterization by sonography --- p.34 / Chapter 2.4 --- Color Power Angiography --- p.38 / Chapter Chapter 3 --- Hypothesis & Aims / Chapter 3.1 --- Hypothesis --- p.44 / Chapter 3.2 --- Aims & Objectives --- p.45 / Chapter Chapter 4 --- Material and Methods / Chapter 4.1 --- Materials --- p.47 / Chapter 4.2 --- Mode of confirmation --- p.52 / Chapter 4.3 --- Final number of subjects recruited --- p.54 / Chapter 4.4 --- Method for obtaining CD and CPA image --- p.58 / Chapter 4.5 --- Method for image analysis --- p.61 / Chapter 4.6 --- Statistical analysis --- p.68 / Chapter Chapter 5 --- Results / Chapter 5.1 --- Qualitative CD and CPA images assessment --- p.70 / Chapter 5.2 --- Interobserver qualitative analysis --- p.78 / Chapter 5.3 --- Spectral analysis --- p.84 / Chapter 5.4 --- Semi-quantitative signal parameters --- p.87 / Chapter 5.5 --- Dominance of quantified signals --- p.91 / Chapter 5.6 --- Distribution of signals in various lesions (graphical presentation) --- p.97 / Chapter 5.7 --- Penetrating vessel --- p.103 / Chapter 5.8 --- Relationship between size of lesion and quantified signal parameters --- p.104 / Chapter Chapter 6 --- Discussion / Chapter 6.1 --- Study Review --- p.109 / Chapter 6.2 --- Methods of quantitation --- p.110 / Chapter 6.3 --- Value of quantitation --- p.111 / Chapter 6.4 --- Instrumentation --- p.112 / Chapter 6.5 --- Subjects --- p.114 / Chapter 6.6 --- Image analysis --- p.115 / Chapter 6.7 --- Results --- p.117 / Chapter 6.8 --- Relationship between size and amount of signals --- p.131 / Chapter 6.9 --- Differentiation of focal hepatic lesions --- p.132 / Chapter 6.10 --- Origin of CPA signals in small hyperechoic lesions --- p.144 / Chapter 6.11 --- Limitations of CPA in focal hepatic lesion imaging --- p.146 / Chapter 6.12 --- Comparison with similar studies --- p.151 / Chapter 6.13 --- Validation of quantitation results --- p.158 / Chapter Chapter 7 --- Conclusions --- p.159 / References --- p.162 / Legends --- p.176 / Tables --- p.186 / Glossary of abbreviations --- p.193 / Selected publications relevant to thesis --- p.197 / Appendix --- p.198 / Bibliography --- p.205

Tez (Tıpta Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Radyodiagnostik Anabilim Dalı, 2004. / Bibliyografya var.

Foram analisados os efeitos da manobra de preensão manual (PM) na autorregulação encefálica (AE) dinâmica, através de um método não estacionário que utiliza o modelo de autorregressão de médias móveis. Doze indivíduos saudáveis foram orientados a realizar a manobra de PM durante 11 minutos com contração muscular constante e carga de 30% da força máxima. Registraram-se continuamente as medidas da velocidade do fluxo sanguíneo nas artérias cerebrais médias, pressão parcial de CO2 (PCO2) no ar expirado e pressão arterial (PA) não invasiva, durante o repouso (5 min), PM (3 min) e recuperação (3 min). A pressão crítica de fechamento (PCrF) e o produto área-resistência (PAR) foram obtidos empregando-se o método do primeiro harmônico. O índice de autorregulação encefálica (IAE) variável no tempo foi calculado através do modelo da autorregressão de médias móveis. As variáveis foram expressas em porcentagem de variação em relação aos valores obtidos no repouso (30 s previamente ao início da manobra de PM). Não houve alteração significativa da PCO2 do ar expirado durante MP. A PA aumentou continuamente durante a manobra (27% dos valores basais), enquanto que a velocidade do fluxo sanguíneo encefálico elevou-se inicialmente e alcançou um platô (15% dos valores basais). A elevação da PA aumentou o PAR, possivelmente devido à vasoconstricção arteriolar encefálica, o que refletiria a atuação do componente miogênico na regulação do fluxo sanguíneo encefálico; por outro lado, a PCrF reduziu-se, o que representa a ação do mecanismo metabólico. O IAE apresentou diminuição tanto no início quanto ao fim da manobra de PM; este achado pode estar relacionado à reação de alerta e/ou à diferença no tempo de resposta dos mecanismos envolvidos na adaptação neurovascular (mecanismos miogênico, metabólico e neurogênico). Conclui-se que o estudo da AE dinâmica com o modelo da autorregressão de médias móveis, durante a manobra de PM, pode ampliar os conhecimentos acerca das modificações hemodinâmicas encefálicas durante o exercício e elucidar aspectos ainda pouco conhecidos da resposta fisiológica do organismo / We investigated the effect of handgrip (HG) maneuver on time-varying estimates of dynamic cerebral autoregulation (CA), using the autoregressive moving average (ARMA) technique. Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO2 pressure (PETCO2), and noninvasive arterial blood pressure (ABP) were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP), resistance areaproduct (RAP), and time-varying autoregulation index (ARI) were obtained. PETCO2 did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to reach 27% of its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005), which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms. Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism

Estudo realizado na Clínica Obstétrica da Faculdade de Medicina da Universidade de São Paulo, com seiscentos e quarenta e cinco gestantes recrutadas, prospectivamente, para avaliações dopplervelocimétricas das artérias uterinas, por via endovaginal, entre 11 e 13+6 semanas e entre 20 e 24+6 semanas. A partir de um grupo de 344 casos com desfecho normal da gestação, valores de referências para os índices dopplervelocimétricos médios foram estabelecidos, e estes foram significativamente maiores na primeira avaliação do que na segunda. Além disso, os valores se correlacionaram de forma positiva e significativa (IP r= 0,42, IR r= 0,42, AB r= 0,29, p<0,0001). Incisura uterina bilateral foi encontrada em 43,9% dos casos no primeiro exame e 4,4% na segunda etapa. Também foram descritos os valores de sensibilidade, especificidade, valores preditivos, razão de verossimilhança e risco relativo de diferentes parâmetros dopplervelocimétricos para predição da pré-eclâmpsia, diagnosticada em 25 casos. Entre 11 e 13 sem. + 6 dias, as áreas sob as curvas de caracterísiticas operacionais dos três índices dopplervelocimétricos foram de 0,51. A maioria dos achados dopplervelocimétricos, nesta fase da gestação, não identificou gestações com risco significativamente aumentado para pré-eclâmpsia. Já, entre 20 e 24 sem. + 6 dias, as áreas sob as curvas de características operacionais foram maiores (IP= 0,66, IR= 0,65, AB= 0,65) e o grupo com índices dopplervelocimétricos acima do percentil 85 e/ou incisura bilateral apresentou risco significativamente aumentado, para o posterior surgimento de pré-eclâmpsia na gestação. Entretanto, a sensibilidade e o valor preditivo positivo foram baixos, e não encorajam o uso desse método para predição da doença hipertensiva específica da gestação em nossa população. / At São Paulo University Medical School, six hundred and forty five pregnant women were prospectively recruited for a longitudinal study involving transvaginal uterine artery Doppler assessment at 11?13+6 weeks and 20?24+6 weeks. Reference values for mean uterine artery Doppler indices were established from 344 cases with normal pregnancy outcome. Values found in the first examination were significantly higher and positively correlated to values obtained in the second examination (PI r= 0.42, RI r= 0.42, SD r= 0.29, p<0.0001). Bilateral notches were found in 43.9% of the cases examined between 11 and 13 weeks, and 4.4% of the cases in the second assessment. Twenty-five cases subsequently developed pre-eclampsia. Sensitivity, specificity, positive and negative predictive values, likelihood ratios and relative risks were calculated for various uterine artery Doppler findings. Between 11 and 13+6 weeks, the ROC curve area was 0.51 for all three indices. At this stage, most uterine artery Doppler findings were not associated with increased risk of pre-eclampsia. At 20 to 20+6 weeks, ROC curve areas were higher (PI= 0.66, RI= 0.65, SD= 0.65) and increased impedance to flow (above the 85th centile) and/or bilateral notches were associated with a significant increase of the risk for the subsequent development of pre-eclampsia. However low sensitivity and positive predictive values do not support this as a screening method for pre-eclampsia in our population.

INTRODUÇÃO: O duplex-Doppler e a ultrassonografia com contraste são métodos pouco estudados em lesões mamárias. No entanto, em outros órgãos, têm se mostrado úteis na distinção entre lesões benignas e malignas. O objetivo deste trabalho é caracterizar os achados ao Doppler colorido pré e pós-contraste nos nódulos sólidos de mama, correlacionando-os com os resultados anatomopatológicos. MATERIAL E MÉTODOS: Setenta nódulos sólidos da mama foram avaliados por meio de ultrassonografia convencional e duplex-Doppler colorido antes e após a injeção do meio de contraste (ultrassonografia contrastada), no período compreendido entre março de 2007 e janeiro de 2008, e seus resultados foram comparados à análise histológica (padrão-ouro). Todas as pacientes assinaram o Termo de Consentimento Livre e Esclarecido, aprovado pelo Comitê de Ética da FMUSP. O estudo ultrassonográfico modo B avaliou a morfologia do nódulo e o classificou conforme o léxico BI-RADS. Ao duplex-Doppler colorido observou-se a vascularização nodular, descrevendo-se o número de vasos presentes (0 = avascularizado; 1 ou 2 = hipovascularizado, 3 = hipervascularizado), sua morfologia (regular ou tortuoso) e sua distribuição (periférica ou central). Os índices de resistividade e a presença de vaso penetrante também foram avaliados. A partir de dados da literatura criou-se um critério de classificação que permitiu estratificá-los entre provavelmente benigno (nódulos avasculares ou hipovasculares, com vasos regulares e distribuição periférica), provavelmente maligno (nódulos hipervasculares, com vasos tortuosos e distribuição central) ou suspeitos (qualquer outra associação desses fatores). No estudo contrastado foram realizadas análises cinética (avaliando-se os tempos de início da contrastação e do clareamento do nódulo, além da análise da intensidade da contrastação, de maneira subjetiva) e morfológica (utilizando-se os mesmos critérios da análise com Doppler). RESULTADOS: A análise histológica resultou em 25 lesões malignas e 45 lesões benignas. A classificação BI-RADS teve sensibilidade de 100%, especificidade de 66,6%, valor preditivo positivo (VPP) de 62,5% e valor preditivo negativo (VPN) de 100%. A análise com Doppler mostrou sensibilidade de 88%, especificidade de 57,7%, VPP de 53,6% e VPN de 89,9%. Após a injeção do meio de contraste, esses valores passaram para: 92%, 46,6%, 48% e 91%, respectivamente. Os índices de resistividade foram significativamente mais altos em lesões malignas na análise com Doppler colorido ( < 0,001). Houve relação estatística significante entre a presença de vaso penetrante e malignidade ( < 0,001). A associação entre os critérios de classificação BI-RADS e Doppler colorido mostrou sensibilidade de 100%, especificidade de 86,6%, VPP de 80,7% e VPN de 100%. A associação entre BI-RADS e ultrassonografia contrastada resultou em sensibilidade de 100%, especificidade de 80%, VPP de 73,5% e VPN de 100%. A análise cinética subjetiva não conseguiu diferenciar entre nódulo benigno e maligno (tempo do início da contrastação = 0,816, tempo de clareamento da lesão = 0,622 e realce da lesão = 0,020). CONCLUSÃO: Os critérios adotados para o duplex-Doppler colorido associados ao BI-RADS fornecem os melhores resultados na distinção entre lesões benignas e malignas da mama. O estudo contrastado não acrescentou informações adicionais às análises prévias. / OBJECTIVE: The duplex-Doppler ultrasound and contrast enhanced ultrasound (CEUS) are poorly studied in breast lesions. However, in the other organs they have been proved to be useful in mass differentiation. Our objective is to characterize the Doppler findings before and after contrast agent injection in solid breast lesions then correlate them with pathological findings in order to evaluate the applicability of these methods in the differentiation of benign and malignant lesions. MATERIALS AND METHODS: Seventy solid breast masses were evaluated by conventional ultrasonography and duplex-color Doppler before and after injection of contrast medium (ultrasound contrast) in the period between March 2007 and January 2008 and their results were compared to histology (gold standard). All patients signed a consent form approved by the Ethics Committee of FMUSP. At gray-scale US the lesions were described and classified according to the BI-RADS lexicon. At duplex-Doppler we observed the lesion vascularity: avascular, hypovascular (one or two arteries) or hypervascular (three or more arteries); distribution (central or peripheral) and shape (regular or tortuous). If there was a penetrating artery, it was reported. We also observed resistive index. Based on literature data criterion was set up for classification which allowed to stratify breast lesions among probably benign (avascular or hypovascular masses, with regular vessels and peripheral distribution); probably malignant (hypervascular masses with tortuous and central vessels) or suspicious (any other combination of those factors). Kinetic analysis (wash in and wash out times, besides mass enhancement, in a subjective manner) and morphological analysis (using the same criteria of analysis with Doppler) were described in contrast study. RESULTS: Percutaneous biopsy revealed 25 malignant and 45 benign lesions. Morphologic analysis using gray-scale sonography and classified according the BI-RADS lexico showed sensitivity of 100% and specificity of 66.6%, positive and negative predictive values of 62.5% and 100% respectively. Doppler sonography, sensitivity, specificity, positive and negative predictive values were 88%; 57.7%; 53.6% and 89.9%. After contrast agent injection sensitivity, specificity, positive and negative predictive values changed to 92%; 46.6%; 48% and 91% respectively. The association among morphological and CDUS analysis findings resulted in a sensitivity of 100%, specificity of 86.6%, PPV 80.7% and NPV 100%. When morphological findings and CEUS analysis were associated values became 100% sensitivity, 80% specificity, 73.5% PPV, and 100% NPV. Resistive index was significantly higher ( < 0,001) in malignant lesions before and after contrast injection. Wash in and wash out times were similar for benign and malignant lesions (wash-in = 0,816, wash-out = 0,622 and intensity = 0,020). CONCLUSION: Duplex-Doppler criteria associated to BI-RADS classification proved to be the best combination to distinguish malignant lesions of the breast. CEUS evaluation did not provide additional information.