Title page, contents and summary only. The complete thesis in print form is available from the University of Adelaide Library. / "In early arthritis, it is important to make a diagnosis before structural damage has occurred, with early disease modifying therapy effective in improving long term outcomes. The first part of this thesis addresses the deficiency in our current knowledge of standardisation and reproducibility of ultrasound (US) findings. Chapter 2 describes a standardised protocol developed for assessing the metacarphphalangeal (MCP) joints and novel measurements of synovial inflammation. Chapter 3 compares early arthritis subjects to a control group, and showed significantly more US synovitis and abnormally increased measurements, with extensor tenosynovitis (ET) and power Doppler (PD_ positivity highly specific to the early arthritis group. Chapter 4 validates HRUS findings in a subset of subjects using MRI as the reference standard..Chapter 5 presents longitudinal data which suggests that clnical swelling and PD positivity at the MCP joints were the most sensitive to change as a reseult of disease-modifying therapy. Chapter 6 validates an US assessment tooldevelopedbadsed on “sentinel joints” whilst factors that may hemp to differentiate subjects with polyarthralgias from those with early RA are identified in chapter 7. The results of this study suggest that early RA needs to be redefined in the light of our US findings. The prognostic value of early US abnormalities will contlinue to be investigated." -- from Abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1317258 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008

published_or_final_version / abstract / Medicine / Master / Master of Philosophy

published_or_final_version / Obstetrics and Gynaecology / Master / Master of Philosophy

Homozygous α0-thalassemia is a serious autosomal recessive disorder with poor fetal outcome and severe maternal complications. Conventionally, prenatal diagnosis is performed by an invasive test. A non-invasive approach using serial ultrasonography can effectively reduce the need for invasive tests in unaffected pregnancies. For two-dimensional ultrasound prediction, a total of 777 at-risk fetuses were studied from 12 to 20 weeks between 1995 and 2006. At 12–15 weeks’ gestation, the highest sensitivity (98.3%) was achieved by the combination of fetal cardiothoracic ratio (CTR) and/or middle cerebral artery peak systolic velocity (MCA-PSV) at a false-positive rate of 15.8%. At 16–20 weeks’ gestation, the sensitivity of CTR was 100.0%, but the false-positive rate was 5.2%. In contrast, the false-positive rate of MCA-PSV alone was 1.4% and that of the combination of CTR and MCA-PSV was 0%, although their sensitivities were less than 65%. In a cross-sectional retrospective study of 546 samples at-risk and control (268 fetal and 278 neonatal cord blood), the degree of anemia was only mild in 27.5% of the affected fetuses (see chapter 3 for definition of mild anemia). Because MCA-PSV is not very predictive of mild anemia, this may be one of the reasons why MCA-PSV is not very sensitive in predicting an affected pregnancy. A total of 832 at-risk pregnancies were studied using same noninvasive approach at Maternal and Neonatal Hospital of Guangzhou (MNH) and Tsan Yuk Hospital (TYH). The overall sensitivity and specificity of the noninvasive approach was 100% and 95.6% respectively. At MNH, the need for an invasive test was reduced by 78.6%, and all the affected pregnancies were diagnosed before 24 weeks’ gestation. After adequate training and monitoring the quality of the subsequent ultrasound examinations, the results achieved at MNH were comparable to TYH, with at-risk pregnancies including the affected ones being seen at a more advanced gestation at MNH. In a retrospective review of 361 women at risk of carrying an affected fetus, 311 (86.2%) opted for the non-invasive approach using CTR and/or placenta. The cost saving of this non-invasive approach was relatively small (HK$ 2,651) in comparison to the cost of the whole prenatal screening program. On the other hand, the non-invasive approach was more expensive than the direct invasive approach for low MCV couples, as well as couples discordant for α-thalassemia and β-thalassemia. ages. These results support the adoption of non-invasive approach in which routine invasive test or karyotyping is no longer performed. A total of 106 at-risk pregnancies and normal controls were prospectively studied using three-dimensional ultrasonography. Placental volume (PV) at 11-14 weeks, and PV/CRL quotient at 9-14 weeks’ gestation of affected pregnancies were significantly greater than unaffected pregnancies (P<0.05). Using a cut-off point of 1.2ml/mm for PV/CRL quotient to predict an affected pregnancy, the sensitivity, and specificity was 96.2%, and 100.0% respectively. / published_or_final_version / Obstetrics and Gynaecology / Master / Doctor of Medicine

Thesis (MTech (Radiography))--Cape Peninsula University of Technology, 2006. / The knee is one of the most complicated joints in the body. The deep infrapatellar bursa being only a small water-pocket and forming a small part of the knee. The deep infrapatellar bursa can get inflamed and cause great discomfort, especially to professional sportsmen and -women. If such a inflammation is present, a common treament option are to inject a cortisone solution into the bursa for quick relieve and healing. This study was performed to investigate the specific ultrasound features of a normal deep infrapatellar bursa. Thus enableing more specific and accurate diagnosis of deep infrapatellar bursitis or not, which in turn leads to quicker recovery of the patients.

M.Tech. / To determine whether a combination of real-time B-Mode ultrasound, Doppler Color flow and Power Doppler flow mapping would be reliable in differentiating benign from malignant breast nodules in an attempt to avoid unnecessary biopsies, where after ultrasound guidelines would be formulated. A quantitative cross-sectional comparative descriptive design in a study population which consisted of 62 women over the age of 35 years who came to Klerksdorp Radiology services for mammography. Both breast ultrasound imaging and mammography was used as a routine procedure as part of the workup for the classification of breast nodules, before histologic specimens were obtained. All nodules were classified according to the ultrasonographic BI-RADS lexicon and compared with the pathologic results. Of the 63 patients, 63 breast nodules were detected and confirmed by biopsy. Thirty seven (59%) nodules were found to be malignant and 26 (41%) were benign according to biopsy results. Mammography had 87% sensitivity and ultrasound 60% sensitivity in detecting malignancy. It is recommended that B-mode, Color Doppler flow and Power Doppler flow mapping be used in combination with mammography for screening as a gold standard.

published_or_final_version / Medicine / Master / Doctor of Medicine

No description available.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [273]-288).

This work explored the design considerations on the real-time medical ultrasound adaptive beamformer implementations using different computing platforms: CPU, GPU and FPGA. Adaptive beamforming has been well considered as an advanced solution for improving the image quality of medical ultrasound imaging machines. Although it provides promising improvements in lateral resolution, image contrast and imaging penetration depth, the use of adaptive beamforming is substantially more computationally demanding than conventional delay-and-sum beamformers. In order not to compromise the real-time performance of medical ultrasound systems, an accelerated solution is desirable. In this work, CPU implementation was used as a baseline implementation, based on which the intrinsic characteristics of the algorithm were analyzed. After the analysis of a particular adaptive beamforming algorithm, minimum-variance adaptive beamforming, two design parameters M and L were found to affect the implementation performance in two aspects: computational demand and image quality. The trends of the two aspects were contradictory with respect to the increment of M and L values. In our experiments, when M and L increased, the computational demand increased in a cubic curve; meanwhile, the image quality did not have much improvement when the increased values of M and L entered certain ranges. Since we targeted at a real-time solution without sacrificing the good image quality that adaptive beamforming proposed, a tradeoff was made on the selection of M and L values to balance the two contradictory requirements. Built upon the theoretical algorithmic analysis of the real-time adaptive beamformer realization, the implementations were developed with FPGA and GPU. While a dedicated hardware solution might be able to address the computational demand of the particular design, the need for an efficient algorithm exploration framework demanded a reprogrammable platform solution that was high-performance and easily reconfigurable. Besides, although a simple processor could provide convenient algorithm exploration via software development environment, real-time performance was usually not achievable. As a result, a reprogrammable medical ultrasound research platform for investigating advanced imaging algorithms was constructed in our project. The use of FPGA and GPU for implementing the real-time adaptive beamformer on our platform was explored. In our test cases, both FPGA- and GPUbased solutions achieved real-time throughput exceeding 80 frames-per-second, and over 38x improvement when compared to our baseline CPU implementation. Moreover, the implementations were also evaluated in terms of portability, data accuracy, programmability, and system integration. Due to its high power consumption, high-performance GPU solution is best suited for bedside applications, while FPGAs are more suitable for portable and hand-held medical ultrasound machines. Besides, while the development time on GPU platform remains much lower than its FPGA counterpart, the FPGA solution is effective in providing the necessary I/O bandwidth to enable an end-to-end real-time reconfigurable medical ultrasound image formation system. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy