"Modern ultrasound scanners are portable and have become very useful for clinical diagnosis. However, they have limitations for field use purposes, primarily because they occupy both hands of the physician who performs the scanning. The goal of this thesis is to develop a wearable voice-controlled ultrasound scanner system that would enable the physician to provide a fast and efficient diagnosis. This is expected to become very useful for emergency and trauma applications. A commercially available ultrasound scanner system, Terason 2000, was chosen as the basis for development. This system consists of a laptop, a hardware unit containing the RF beamforming and signal processing chips and the ultrasound transducer. In its commercial version, the control of the ultrasound system is performed via a Graphical User Interface with a Windows-application look and feel. In the system we developed, a command and control speech recognition engine and a noise-canceling microphone are selected to control the scanner using voice commands. A mini-joystick is attached to the top of the ultrasound transducer for distance and area measurements and to perform zooming of the ultrasound images. An eye-wear viewer connected to the laptop enables the user to view the ultrasound images directly. Power management features are incorporated into the ultrasound system in order to conserve the battery power. A wireless connection is set up with a remote laptop to enable real-time transmission of wireless images. The result is a truly untethered, voice-controlled, ultrasound system enclosed in a backpack and monitored by the eye-wear viewer. (In the second generation of this system, the laptop is replaced by an embedded PC and is incorporated into a photographer’s vest). The voice-controlled system has to be made reliable under various forms of background noise. Three command and control speech recognition systems were selected and their recognition performances were determined under different types and levels of ambient noise. The variation of recognition rates was also analyzed over 6 different speakers. A detailed testing was also conducted to identify the ideal combination of a microphone and speech recognition engine suitable for the ultrasound scanner system. Six different microphones, each with their own unique methods of implementing noise cancellation features, were chosen as candidates for this analysis. The testing was conducted by making recordings inside a highly reverberant acoustic noisy chamber, and the recordings were fed to the automatic speech recognition engines offline for performance evaluation. The speech recognition engine and microphone selected as a result of this extensive testing were then incorporated into the wearable ultrasound scanner system. This thesis also discusses the implementation of the human-speech interface, which also plays a major role in the effectiveness of the voice-controlled ultrasound scanner system."

Cardiac diseases and conduction disorders are associated with stroke, heart failure and sudden cardiac death and are a major health concern worldwide. In the US alone, more than 14 million people suffer from heart rhythm disorders. Current mapping and characterization techniques in the clinic involve invasive procedures, which are time-consuming, costly, and may involve ionizing radiation. In this dissertation, we introduce Electromechanical Wave Imaging (EWI) as a non-invasive, ultrasound-based treatment planning tool for pre-procedure characterization and assessment of arrhythmia in the clinic. In particular, standard EWI processing methods for mapping the electromechanical wave (EW), i.e. the onset of the mechanical activity following the depolarization of the heart, are described and detailed. Next, validation of EWI is performed with 3D electromechanical mapping and the EW propagation is shown to follow the electrical activation in all four chambers of the heart. Demonstration of the value of EWI for the characterization of cardiac arrhythmia is accomplished in vivo in a large animal model. First, EWI is shown capable of localizing the earliest region of activation in the ventricles during pacing from a standard pacemaker lead, as well as during pacing from a novel biological pacemaker. Repeatability is also demonstrated between consecutive cardiac cycle during normal sinus rhythm and during pacing. Then, in the atria, we demonstrate that EWI is capable of accurately identifying focal sources while pacing from several locations in both the left and right atria. In addition to being capable of localizing the focal source, EWI is also shown capable of differentiating between endocardial and epicardial focal sources. Finally, it is shown that EWI can correctly identify regions of infarction and monitor formation of infarcts over several days, after ligation of the left anterior descending coronary artery of canine hearts. Novel processing techniques aimed at extracting quantitative parameters from EWI estimates are then developed and implemented. Details of the implementation of processing methods for estimating the velocity of the EW propagation are presented, and a study of the EW velocity values in a canine heart before and after infarct formation is conducted. Electromechanical cycle length mapping (ECLM), which is aimed at extracting local rates of electromechanical activation in the heart, is then introduced and its implementation detailed. ECLM is subsequently validated in a paced canine heart in vivo. Finally, initial clinical feasibility is demonstrated. First, in the study of treatment of chaotic arrhythmia such as in the case of atrial fibrillation patients undergoing direct current cardioversion, ECLM is shown to be able to confirm acute treatment success. Then, the clinical value of EWI in the electrophysiology lab as a treatment planning tool for the characterization of focal arrhythmia is shown in ventricular tachycardia and Wolff-Parkinson-White patients. EWI is currently only a step away from real-world clinical application. As a non-invasive, ultrasound-based imaging modality, EWI is capable of providing relevant insights into the origins of an arrhythmia and has the potential to position itself in the clinic as a uniquely valuable pre-procedure planning tool for the non-invasive characterization of focal arrhythmias.

Over the past 10 years, Compressive Sensing has gained a lot of visibility from the medical imaging research community. The most compelling feature for the use of Compressive Sensing is its ability to perform perfect reconstructions of under-sampled signals using l1-minimization. Of course, that counter-intuitive feature has a cost. The lacking information is compensated for by a priori knowledge of the signal under certain mathematical conditions. This technology is currently used in some commercial MRI scanners to increase the acquisition rate hence decreasing discomfort for the patient while increasing patient turnover. For echography, the applications could go from fast 3D echocardiography to simplified, cheaper echography systems. Real-time ultrasound imaging scanners have been available for nearly 50 years. During these 50 years of existence, much has changed in their architecture, electronics, and technologies. However one component remains present: the beamformer. From analog beamformers to software beamformers, the technology has evolved and brought much diversity to the world of beam formation. Currently, most commercial scanners use several focalized ultrasonic pulses to probe tissue. The time between two consecutive focalized pulses is not compressible, limiting the frame rate. Indeed, one must wait for a pulse to propagate back and forth from the probe to the deepest point imaged before firing a new pulse. In this work, we propose to outline the development of a novel software beamforming technique that uses Compressive Sensing. Time-domain Compressive Beamforming (t-CBF) uses computational models and regularization to reconstruct de-cluttered ultrasound images. One of the main features of t-CBF is its use of only one transmit wave to insonify the tissue. Single-wave imaging brings high frame rates to the modality, for example allowing a physician to see precisely the movements of the heart walls or valves during a heart cycle. t-CBF takes into account the geometry of the probe as well as its physical parameters to improve resolution and attenuate artifacts commonly seen in single-wave imaging such as side lobes. In this thesis, we define a mathematical framework for the beamforming of ultrasonic data compatible with Compressive Sensing. Then, we investigate its capabilities on simple simulations in terms of resolution and super-resolution. Finally, we adapt t-CBF to real-life ultrasonic data. In particular, we reconstruct 2D cardiac images at a frame rate 100-fold higher than typical values.

Modern cancerous tumor diagnostics is nearly impossible without invasive methods, such as biopsy, that may require involved surgical procedures. In recent years some work has been done to develop alternative non-invasive methods of medical diagnostics. For this purpose, the data obtained from an ultrasound image of the body crosssection, has been analyzed using statistical models, including Rayleigh, Rice, Nakagami, and K statistical distributions. The homodyned-K (H-K) distribution has been found to be a good statistical tool to analyze the envelope and/or the intensity of backscattered signal in ultrasound tissue characterization. However, its use has usually been limited due to the fact that its probability density function (PDF) is not available in closed-form. In this work we present a novel closed-form representation for the H-K distribution. In addition, we propose using the first order approximation of the H-K distribution, the I-K distribution that has a closed-form, for the ultrasound tissue characterization applications. More specifically, we show that some tissue conditions that cause the backscattered signal to have low effective density values, can be successfully modeled by the I-K PDF. We introduce the concept of using H-K PDF-based and I-K PDF-based entropies as additional tools for characterization of ultrasonic breast tissue images. The entropy may be used as a goodness of fit measure that allows to select a better-fitting statistical model for a specific data set. In addition, the values of the entropies as well as the values of the statistical distribution parameters, allow for more accurate classification of tumors. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Xie Jun. / "July 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 177-204). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Heart disease has remained the deadliest disease in the United States for the past 100 years. Imaging methods are frequently employed in cardiology in order to help clinicians diagnose the specific type of heart disease and to guide treatment decisions. Ultrasound is the most frequently used imaging modality in cardiology because it is inexpensive, portable, easy to use, and extremely safe for patients. Using a variety of imaging processing techniques, deformations exhibited by the cardiac tissue during contraction can be imaged with ultrasound and used as an indicator of myocardial health. This dissertation will demonstrate the clinical implementation of two ultrasound-based strain estimation techniques developed in the Ultrasound and Elasticity Imaging Laboratory at Columbia University. Each of the two imaging methods will be tailored for clinical applications using techniques for optimal strain estimation derived from ultrasound and imaging processing theory. The motion estimation rate (MER) used for strain estimation is examined in the context of the theoretical Strain Filter and used to increase the precision of axial strain estimation. Diverging beam sequences are used to achieve full-view high MER imaging within a single heartbeat. At approximately 500 Hz, the expected elastographic signal-to-noise ratio (E(SNRe|ε)) of the axial strain becomes single-peaked, indicating an absence of “peak-hopping” errors which can severely corrupt strain estimation. In order to mediate the tradeoff in spatial resolution resulting from the use of diverging beams, coherent spatial compounding is used to increase the accuracy of the lateral strain estimation, resulting in a more physiologic strain profile. A sequence with 5 coherently compounded diverging waves is used at 500 Hz to improve the radial SNRe of the strain estimation compared to a single-source diverging sequence at 500 Hz. The first technique, Myocardial Elastography (ME), is used in conjunction with an intracardiac echocardiography (ICE) system to image the formation of thermal ablation lesions in vivo using a canine model (n=6). By comparing the systolic strain before and after the formation of a lesion, lesion maps are generated which allow for the visualization of the lesion in real-time during the procedure. A good correlation is found between the lesion maps and the actual lesion volume as measured using gross pathology (r2=0.86). The transmurality of the lesions are also shown to be in good agreement with gross pathology. Finally, the feasibility of imaging gaps between neighboring lesions is established. Lesion size and the presence of gaps have been associated with the success rate of cardiac ablation procedures, demonstrating the value of ME as a potentially useful technique for clinicians to help improve patient outcomes following ablation procedures. The second technique, Electromechanical Wave Imaging (EWI), is implemented using a transthoracic echocardiography system in a study of heart failure patients (n=16) and healthy subjects (n=4). EWI uses the transient inter-frame strains to generate maps of electromechanical activation, which are then used to distinguish heart failure patients from healthy controls (p<.05). EWI was also shown to be capable of distinguishing responders from non-responders to cardiac resynchronization therapy (CRT) on the basis of the activation time of the lateral wall. These results indicate that EWI could be used as an adjunct tool to monitor patient response to CRT, in addition to helping guide lead placement prior to device implantation.

Orientador: Jorge Nahás Neto / Coorientador: Eliana Aguiar Petri Nahás / Banca: Paulo Traiman / Banca: Eduardo Carvalho Pessoa / Resumo: Avaliar o efeito da isoflavona da soja sobre o tecido mamário em mulheres na pós-menopausa. Trata-se de estudo clínico, prospectivo, randomizado, duplo-cego, placebo controlado, envolvendo 80 mulheres na pós-menopausa com sintomas vasomotores, idade entre 45 a 70 anos, acompanhadas no Ambulatório de Climatério e Menopausa da Faculdade de Medicina de Botucatu-Unesp, de janeiro de 2005 a dezembro de 2006. Na randomização, 40 pacientes receberam 100 mg isoflavona da soja/dia (duas cápsulas de 125 mg de extrato seco de glicine Max) e 40 pacientes placebo (duas cápsulas de lactose) durante 10 meses. A densidade mamária (DM) foi avaliada pela mamografia e o parênquima mamário pela ultrassonografia de mamas no início e após dez meses de seguimento. Para análise estatística foram utilizados o teste t-Student, ANOVA, teste de Mann-Whitney e teste do Qui-Quadrado. Na comparação das características clínicas iniciais entre os grupos de usuárias de isoflavona e placebo, não houve diferenças significantes, com valores médios de idade de 55,1±6,0 e 56,2±7,7 anos, tempo de menopausa de 6,6±4,8 e 7,1±4,2 anos e IMC de 29,7±5,0 e 28,5±4,9 kg/m2, respectivamente (p>0,05). Concluíram o estudo 32 pacientes sob isoflavona e 34 sob placebo. Na comparação da densidade mamográfica entre os momentos inicial e final, não houve diferença estatisticamente significativa. Na avaliação do parênquima mamário pela ultrassonografia, não houve diferença entre os grupos. Na comparação entre os momentos dentro de cada grupo, não foram constatadas diferenças significativas nos parâmetros da mamografia e ultrassonografia. No período de 10 meses, o uso de isoflavona de soja não modificou o tecido mamário, avaliado pela mamografia e ultrassonografia, em mulheres na pós-menopausa / Abstract: To evaluate the effect of soy isoflavone on breast tissue in postmenopausal women. This study is a prospective, randomized, double-blind, placebo-controlled trial involving 80 postmenopausal women with vasomotor symptoms, aged 45-70 years, followed in Climacteric and Menopause Clinic of the Botucatu Medical School-UNESP, from January 2005 to December 2006. At randomization, 40 patients received 100 mg of soy isoflavone/day (two capsules of 125 mg standardized soy extract, Glicine max) and 40 patients, placebo (two capsules of lactose) for 10 months. The breast density was evaluated by mammography and breast parenchyma by ultrasound, at baseline and after ten months of follow-up. The Student t-test, ANOVA, Mann-Whitney and Chi-Square were used in the statistical analysis. In comparison of baseline clinical characteristics between the isoflavone and placebo groups, there were no significant differences, with mean age of 55.1 ± 6.0 and 56.2 ± 7.7 years, duration of menopause 6.6 ± 4.8 and 7.1 ± 4.2 years and BMI 29.7 ± 5.0 and 28.5 ± 4.9 kg/m2, respectively (p> 0.05). Concluded the study, 32 patients on isoflavone and 34 in the placebo group. In comparison in mammographic density (MD) between moments, baseline and final, there was no difference statistically significant. In the evaluation of breast parenchyma by ultrasound, there was no difference between groups. In comparing the moments within each group, there were no significant differences in the parameters of mammography and ultrasound. In 10 months, the use of soy isoflavone did not affect breast tissue, as assessed by mammography and ultrasound, in postmenopausal women / Doutor

Orientador: Maria Jaqueline Mamprim / Coorientador: Carlos Roberto Teixeira / Banca: Raquel Sartor Marcelino / Banca: Alessandra Melchert / Resumo: O atendimento de cães com sobrepeso e obesos na rotina clínica de animais de companhia tem sido cada vez mais frequente. O objetivo do presente estudo foi avaliar as alterações hepáticas parenquimatosas e hemodinâmicas, por meio da ultrassonografia bidimensional e Doppler, em três grupos de cães com diferentes escores de condição corporal - G1 (peso ideal/controle), G2 (sobrepeso) e G3 (obesos) -, sem doenças hepáticas por outras causas de base. Houve correlação positiva entre o G3 e os seguintes fatores: aumento da ecogenicidade do parênquima hepático, aumento das dimensões hepáticas, hiperlipidemia, e morfologia anormal da onda da veia hepática (VH). Diferença significativa na velocidade média do fluxo portal (Vméd.VP) foi observada entre G1 (17,23 ± 3,7cm/s) e G3 (13,66 ± 2,56cm/s), no volume do fluxo portal (VFVP) entre G1 (32,69 ± 11,86mL/min/kg) e G2 (19,58 ± 7,68mL/min/kg) e entre G1 e G3 (15,22 ± 8mL/min/kg), no índice hepatorrenal entre G2 (1,1 ± 0,29) e G3 (1,28 ± 0,22), nos níveis séricos de fosfatase alcalina (FA) entre G1 e G3, de gama glutamiltransferase (GGT) entre G1 e G2 e de colesterol entre G1 e os demais grupos. Não houve diferença significativa no índice de congestão portal (ICP), no índice de resistividade da artéria hepática (IRAH), no diâmetro e área da veia porta e nos níveis séricos de alanina aminotransferase (ALT) e triglicérides, entre os grupos. Concluiu-se que a obesidade pode levar ao desenvolvimento de alterações parenquimatosas e hemodinâmicas no fígado de cães / Abstract: Veterinary care of overweight and obese dogs in small animal clinical sciences has become increasingly common. The aim of the present study was to investigate, using two dimensional and Doppler sonography, parenchymal and hemodynamic changes in three groups of dogs, according to body score condition (G1, ideal body weight/control; G2, overweight; G3, obese), without hepatic diseases due to other causes. A positive correlation was found between G3 and the characteristics described below: increased liver echogenicity, hepatomegaly, hiperlipidemia and abnormal hepatic vein Doppler waveform pattern. There was statistical difference in the mean portal blood flow velocity between G1 (17,23 ± 3,7cm/s) and G3 (13,66 ± 2,56cm/s), in the portal blood flow between G1 (32,69 ± 11,86mL/min/kg) and G2 (19,58 ± 7,68mL/min/kg) and between G1 and G3 (15,22 ± 8mL/min/kg), in the hepatorenal index between G2 (1,1 ± 0,29) and G3 (1,28 ± 0,22), in serum levels of alkaline phosphatase (ALP) between G1 and G3, in levels of gamma glutamyltranspeptidase (GGT) between G1 and G2 and in levels of cholesterol between G1 and the other groups. There was no statistical difference in the portal vein congestion index, hepatic artery resistance index, portal vein diameter and area and on serum levels of alanine aminotransferase (ALT) and triglycerides between the groups. It was concluded that obesity may be responsible for the development of parenchymal and hemodynamic changes in dog's liver / Mestre

Close integration of front-end electronics and the transducer array within the catheter is critical for successful implementation of CMUT-based intravascular ultrasound (IVUS) imaging catheters to enable next generation imaging tools. Therefore, this research developed and implemented custom-designed electronic circuits and systems integrated with an IC compatible transducer technology for realization of miniature IVUS imaging catheters operating at 10-50 MHz frequency range. In one path of this research, an IC is custom designed in a 0.35-um CMOS process to monolithically integrate with a CMUT array (CMUT-on-CMOS) to realize a single-chip, highly-flexible, forward-looking (FL) IVUS imaging system. The amplifiers that are custom-designed achieved transducer thermal-mechanical noise dominated receive performance in a CMUT-on-CMOS implementation. In parallel to the FL-IVUS effort, for realization of a side-looking IVUS catheter based on an annular phased array, a dynamic receive beamformer IC is custom designed also in a 0.35-um CMOS process. Overall, the circuits and systems developed as part of this dissertation form a critical step in the translation of the research on CMUT-based IVUS catheters into real clinical applications for better management of coronary arterial diseases.

<p>Acoustic radiation force impulses (ARFI) have been used to generated transverse-traveling mechanical waves in various biological tissues. The velocity of these waves is related to a medium's stiffness and thus can offer useful diagnostic information. Consequently, shear wave velocimetry has the potential to investigate cardiac disease states that manifest themselves as changes in tissue stiffness (e.g., ischemia).</p><p> The work contained herein focuses on employing ARFI-based shear wave velocimetry techniques, similar to those previously utilized on other organs (e.g., breast, liver), for the investigation of cardiac tissue. To this end, ARFI excitations were used to generate slow-moving (under 3 m/s) mechanical waves in exposed myocardium (with access granted through a thoracotomy); these waves were then tracked with ultrasonic methods. Imaging techniques to increase frame-rate, decrease transducer/tissue heating, and reduce the effects of physiological motion were developed. These techniques, along with two shear wave velocimetry methods (i.e., the Lateral Time-to-Peak and Radon sum transformation algorithms), were utilized to successfully track shear wave propagation through the mid-myocardial layer <italic>in vitro</italic> and <italic>in vivo</italic>. <italic>In vitro</italic> experiments focused on the investigation of a shear wave anisotropy through the myocardium. This experimentation suggests a moderate shear wave velocity anisotropy through regions of the mid-myocardial layer. <italic>In vivo</italic> experiments focused on shear wave anisotropy (which tend to corroborate the aforementioned <italic>in vitro</italic> results), temporal/spatial stability of shear wave velocity estimates, and estimation of wave velocity through the cardiac cycle. Shear wave velocity was found to cyclically vary through the cardiac cycle, with the largest estimates occurring during systole and the smallest occurring during diastole. This result suggests a cyclic stiffness variation of the myocardium through the cardiac cycle. A novel, on-axis technique, the displacement ratio rate (DRR) method, was developed and compared to conventional shear wave velocitmetry and ARFI imaging results; all three techniques suggest a similar cyclic stiffness variation.</p><p> Shear wave velocimetry shows promise in future investigations of myocardial elasticity. The DRR method may offer a means for transthoracic characterization of myocardial stiffness. Additionally, the future use of transesophageal and catheter-based transducers presents a way of generating and tracking shear waves in a clinical setting (i.e., when epicardial imaging is not feasible). Lastly, it is hoped that continued investigations into the physical basis of these ARFI-generated mechanical waves may further clarify the relationship between their velocity in myocardium and material stiffness.</p> / Dissertation