Increasingly, diagnosis of cardiac disease, relies on computer processing of images to aid decision making. In this thesis, we use echocardiography, which is the most widely used cardiac imaging modality to study the motion of the left ventricle. Currently, clinical reporting of echocardiography examinations is operator-dependent and largely qualitative. Commercially available software does not track the left ven- tricle. Also, it does not provide quantification of regional function. This thesis establishes a framework for the quantitative regional analysis of left ven- tricular function. The endocardial and epicardial contours are automatically tracked during the cardiac cycle. A quantitative measure of regional endocardial wall excur- sion and myocardial thickening, based on a 16-segment model of the heart, is then obtained based on these boundaries. The new tracking framework is based on Kalman filtering which makes a single pre- diction as to the position of the boundary on the next frame. We develop a mea- surement model for the endocardial border, the tissue/blood interface, and the epi- cardium, the tissue/tissue interface. Having tracked the endocardial and epicardial boundaries, we introduce an interpretational space which provides clinically mean- ingful regional quantitative measures of left ventricular function. We illustrate all the concepts on one example. We apply the ideas developed to stress echocardiography, in a small retrospective clinical test.

Thesis (MScEng)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on Sept. 12, 2006). PDF text of dissertation: 164 p. : ill. (some col.) ; 30.31Mb. UMI publication number: AAT 3208116. Includes bibliographical references. Also available in microfilm and microfiche format.

Nasopharyngeal carcinoma (NPC) is the 7th commonest cancer in Hong Kong. Improvements in radiotherapy had increased the cure. Unfortunately, up to 10% of the patient still suffered from local recurrence. Because of the deep location, nasopharyngectomy was considered a difficult operation. Developments in surgical approaches had now established nasopharyngectomy as a standard salvage for locally recurrent NPC. With improvements of endonasal endoscopic instruments and endoscopic techniques, endoscopic nasopharyngectomy as a minimally invasive surgery for salvaging small locally recurrent NPC have been reported in several cohorts with encouraging results. Robotic nasopharyngectomy remained difficult due to tight operation space and instrument considerations. The da Vinci surgical robot was marketed in 1999 as a tool to assist surgeons in performing complex surgical manipulations in tight spaces. It was later adapted to be used in the upper aerodigestive tract for endoscopic resection of small cancers transorally. As the da Vinci surgical robot was not designed for head and neck operations, adaptations are required when we tried to apply it to resect tumours in the nasopharynx. The present study aimed to develop the use of the da Vinci surgical robot to perform minimally invasive operations on the nasopharynx in a cadaveric model. Ten procedures on 3 cadavers were performed with the surgical robot. Due to instrument clutter, a transoral approach was preferred over transnasal approach. In transoral approach, the soft palate obstructs the access to the nasopharynx. We devised three approaches, namely palatal suspension approach, midline palatal split approach and lateral palatal flap approach. We also assess the advantages and limitations of the three approaches. From 2010-2014, 18 robotic nasopharyngectomies were performed. Median operation time was 232 minutes (range 125-574). Estimated median blood loss was 100ml (range 100-1800). Negative margins were achieved in 14 patients. The two-year actuarial local control was 83% and estimated mean survival was 42.7 months (95% confidence interval 35.0-50.3 months). A positive or close margin was significant associated with poor local control but not overall survival. Results were comparable to open or endoscopic nasopharyngectomy. There was no 30 days post-operative mortality but one patient suffered from hypoxic brain damage after developing angioedema in the recovery room. Two patients developed permanent palatal fistulas and one patient had severe trismus after operation. Symptomatic osteoradionecrosis occurred in three patients. When comparing the quality of life assessment with patients after open maxillary swing nasopharyngectomy operation, robotic nasopharyngectomy patients have a higher score in social functioning scale and lower symptoms scores on pain, mouth opening and social eating. The global health score and other functioning scores were statistically not different. Robotic nasopharyngectomy is a feasible minimally invasive operation for resecting selected cases of locally recurrent NPC. The operation is associated with minor long-term complications and better quality of life. Early oncological results in are also encouraging. With rapid development of medical robotic technologies, further research in the field should be continued. / published_or_final_version / Surgery / Master / Master of Surgery

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaves 141-147).

Thesis (Ph.D.)--Arizona State University, 2008. / Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: Sunil K. Agrawal, Dept. of Mechanical Engineering. Includes bibliographical references.

Thesis (Ph. D.)--University of California, Irvine, 2006. / Includes bibliographical references (leaves 152-162).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed July 8, 2010). PDF text: xii, 156 p. : ill. (chiefly col.) ; 6 Mb. UMI publication number: AAT 3366042. Includes bibliographical references. Also available in microfilm and microfiche formats.

Physical therapy is a field with ever increasing demands as the population ages, resulting in a larger number of individuals living with impairments. Therapy is both physically intensive and time intensive for physical therapists, and can require more than one therapist per patient. The use of technology can reduce both these physical and time demands if appropriately applied, while improving repeatability and providing quantitative evaluation of performance. Through these abilities, it may also improve the quality of life for patients. The work presented here explores how the mechanical and controller design of exoskeletons can be used to improve adaptations to new gait patterns in healthy individuals. Armed with this knowledge, new treatment methods can be adapted, applied, and validated for impaired populations with the intention of recovering a more natural gait pattern. First, the ALEX II device is presented. It is a unilateral device, designed to aid in gait training for stroke survivors. The previous version, ALEX I, had several limitations in terms of pelvic freedom, leg range of motion, and the support of the gravitational load. ALEX II was designed to address these issues. Next, a study is presented, using healthy young adults (N=30), in which ALEX II was used to explore how the amount of freedom allowed at the pelvis during gait training affects the level of adaptation subjects are able to achieve. This was evaluated for five separate configurations which resemble existing exoskeletons. It was found that intermediate levels of pelvic freedom degrade the amount of adaptation and that pelvic translation contributes more to this effect than hip abduction/adduction. The next work concerns the design of ALEX III, a bilateral device with twelve active degrees-of-freedom. ALEX III was created to increase the ability to explore the functionality required for gait training, which is why it is capable of controlling 4 degrees-of-freedom at each leg, and 4 degrees-of-freedom at the pelvis. This is followed by the the design of a new type of haptic feedback which utilizes a variable, viscous damping field, which increases the damping coeffiecent as the subject moves away from a specified path. This feedback type was tested in a set of experiments in healthy young adults. The first study (N=32) compared four different settings for the new feedback, finding that while all groups demonstrated adaptations in gait, the lowest rate of change of the damping field exhibited less adaptation. The final study (N=36) compared this haptic feedback to two previously used haptic feedback types. The previously used feedback strategies used a force that pushed the leg either towards or away from the desired path. All three of these strategies were found to produce similar levels of adaptation, however the damping field used much less external force. These findings may change the way exoskeletons for gait training are designed and increase their accessibility. While all the findings need to be validated in impaired populations they can still inform the design of future exoskeletons. The first finding, that providing an intermediate amount of freedom to the pelvis can interfere with gait training, suggests that future devices should have very high amounts of freedom or very restricted pelvic motions. The final finding, that damping fields can be used to induce gait adaptations using a much lower force, can drastically change exoskeleton design and how robotic therapy is provided. Exoskeletons can be made lighter as a result of the force being highly reduced so that lighter weight components can be used, and the dissipative nature of the force reduces dependence on heavy power sources because regenerative breaking can be used to power the device. These factors also make it possible to for devices to be used overground, which may make training more transferable to the real world.