Thesis (Ph. D.)--University of Florida, 1999. / Title from first page of PDF file. Document formatted into pages; contains xiv, 137 p.; also contains graphics. Vita. Includes bibliographical references (p. 129-136).

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 91-99) Also available in print.

Thesis (Ph. D.)--Drexel University, 2005. / Includes abstract. Includes bibliographical references (leaves 170-179).

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Rebecca Richards-Kortum. Vita. Includes bibliographical references.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 138-155). Also available in electronic version.

Dissertation (Ph.D.) -- Worcester Polytechnic Institute. / Keywords: MRI; Image reconstruction; Image registration; Medical image. Includes bibliographical references (leaves 115-137).

Molecular magnetic resonance imaging (MRI) methods have the potential to provide detailed information regarding cellular and molecular processes at small scales within the human body. Nuclear signals from chemical samples can be probed using specialised MRI techniques, to highlight molecular contrast from particular enzymes or metabolites. The aim of the work described in this thesis is to investigate both exogenous and endogenous contrast mechanisms using fluorine MRI and chemical exchange saturation transfer (CEST) respectively, in order to detect molecular changes in vitro. Initial theoretical work investigates the factors which affect fluorine MRI signals and provides a theoretical framework to determine the sensitivity of such experiments. A novel paramagnetic fluorine sensor to detect enzyme activity is then characterised using high field nuclear magnetic resonance (NMR), showing 60 to 70–fold increases in T1 relaxation values upon enzyme interaction. The effects on the fluorine lineshape from varying sample temperature and solvent were investigated. The possibility of imaging is demonstrated, but further investigations using the theoretical framework found pre–clinical implementation of the sensor is limited by the achievable experimental sensitivity. Efforts then focussed on CEST molecular methods, which are not limited by sensitivity. A protocol is developed to target amide protons in an in vitro cancer cell model, with parameters optimised following simulation of the expected contrast. Analysis of CEST results were aided through use of a support vector machine (SVM) to distinguish group differences between cancer cells and control samples. A linear classifier was found to be suitable to discriminate between samples.

Objectives: To investigate the feasibility of real-time three-dimensional (3D) echocardiographic analysis of right ventricular (RV) function in healthy dogs and to compare conventional and 3D echocardiographic (3DE) indices of RV function in dogs with various stages of myxomatous mitral valve disease (MMVD), classified per the guidelines of the American College of Veterinary Internal Medicine, to those from healthy dogs. Animals: Twenty-two healthy dogs and 56 dogs with MMVD Methods: All dogs underwent conventional and 3D echocardiographic examinations. Measurements of 3DE RV function indices including RV end-diastolic volume (EDV), RV end-systolic volume (ESV), RV stroke volume (SV), and RV ejection fraction (EF) were recorded. Measurements of conventional indices of RV function were also obtained. RV EDV, ESV, and SV were indexed to bodyweight (BW) and analyzed using commercially available software. Results: Three-dimensional RV datasets could be acquired and analyzed in all dogs. Intra- and inter-observer coefficents of variation were > 20% for all 3D RV indices. Right ventricular EDV and ESV were decreased and RV EF was increased in dogs with advanced MMVD when compared to controls. Several conventional echocardiographic indices of RV function also differed between the control group and various MMVD groups. Conclusions: Real-time 3DE RV assessment is feasible in normal dogs with acceptable intra- and inter-observer variability. Several 3DE indices of RV systolic function differ between dogs with advanced MMVD when compared to normal dogs. Further investigation is required to determine if these differences have clinical implications. / Master of Science / Background: Myxomatous mitral valve degeneration (MMVD) is the most common acquired heart disease in dogs. Real-time three-dimensional echocardiography (3DE) is a useful imaging modality for evaluation of right ventricular (RV) function in people with left-sided cardiac disease. The utility of 3DE evaluation RV function in dogs with MMVD has not been determined. Objectives: To investigate the feasibility of 3DE analysis of RV function in healthy dogs and to compare conventional and 3DE indices of RV function in dogs with various stages of MMVD to those from healthy dogs. Animals: Twenty-two healthy dogs and 56 dogs with MMVD Methods: All dogs underwent conventional and 3D echocardiographic examinations and measurements of conventional and 3D indices of RV function were recorded. Threedimensional volumetric data were indexed to bodyweight. Measurements were compared between normal dogs and dogs with various stages of MMVD. Results: Three-dimensional RV datasets could be acquired and analyzed in all dogs. Within- and between-observer measurement variation was acceptable for all 3D RV indices. Right ventricular end-diastolic and end-systolic volumes were decreased and ejection fraction was increased in dogs with advanced MMVD when compared to controls. Several conventional echocardiographic indices of RV function also differed between the control group and dogs with various stages of MMVD. Conclusions: Real-time 3DE RV assessment is feasible in normal dogs with acceptable intra- and inter-observer variability. Several 3DE indices of RV systolic function differ between dogs with advanced MMVD when compared to normal dogs. Further investigation is required to determine if these differences have clinical implications.

A maximum-likelihood parameter-estimation method is developed that allows the mean of coarsely digitized data to be determined to far greater precision than that inherent in the digital quantization. The method is used to determine the mean responses of photomultiplier tubes in a medical scintillation camera. The mean responses as determined by the estimation scheme are applied to two tasks. The first is the development and construction of a feedback-control loop to stabilize photomultiplier tube responses. The second is a method to characterize the camera face for the construction of a look-up table of maximum a posteriori position estimates used in image acquisition. The implementation of the parameter-estimation algorithm, its applications in both the stabilization of photomultiplier tube response and image look-up table construction, and the analysis of photomultiplier tube statistics, are considered to be the major contributions of the work presented in this thesis. (Abstract shortened with permission of author.)

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy