Biomedical Engineering and Bioengineering Commons^™

Using Kriging To Interpolate Spatially Distributed Volumetric Medical Data, Stephen M. Matechik

Theses and Dissertations

Routine cases in diagnostic radiology require the interpolation of volumetric medical imaging data sets. Inaccurate renditions of interpolated volumes can lead to the misdiagnosis of a patient's condition. It is therefore essential that interpolated modality space estimates accurately portray patient space. Kriging is investigated in this research to interpolate medical imaging volumes. Kriging requires data to be spatially distributed. Therefore, magnetic resonance imaging (MRI) data is shown to exhibit spatially regionalized characteristics such that it can be modeled using regionalized variables and subsequently be interpolated using kriging. A comprehensive, automated, three-dimensional structural analysis of the MRI data is accomplished to …

Pulse Coupled Neural Networks For The Segmentation Of Magnetic Resonance Brain Images, Shane L. Abrahamson

Theses and Dissertations

This research develops an automated method for segmenting Magnetic Resonance (MR) brain images based on Pulse Coupled Neural Networks (PCNN). MR brain image segmentation has proven difficult, primarily due to scanning artifacts such as interscan and intrascan intensity inhomogeneities. The method developed and presented here uses a PCNN to both filter and segment MR brain images. The technique begins by preprocessing images with a PCNN filter to reduce scanning artifacts. Images are then contrast enhanced via histogram equalization. Finally, a PCNN is used to segment the images to arrive at the final result. Modifications to the original PCNN model are …

Evaluation Of Segmentation For Bone Structures In 3d Rendering Of Ultrasound Residual Limb Images, Min C. Baker

Theses and Dissertations

Prosthetists today widely practice manual socket fitting, which produces subjective, inconsistent results. To address this problem, the Computerized Anthropometry Research and Design (CARD) Laboratory is developing a computer-aided socket design system that acquires ultrasound datasets of an amputee's residual limb, creates a 3D model, and helps identify load- bearing and pressure-relief areas. This research project focuses on providing 3D visualization of a residual limb to support the CARD Laboratory's efforts. Creating the 3D model of the skin and two bone contours requires two major steps: segmentation to identify the objects of interest and a surface tracking algorithm to generate the …

Clustered Microcalcification Detection Using Optimized Difference Of Gaussians, Edward M. Ochoa

Theses and Dissertations

The objective of this thesis is to design an automated microcalcification detection system to be used as an aid in radiologic mammogram interpretation. This research proposes the following methodology for clustered microcalcification detection. First, preprocess the digitized film mammogram to reduce digitization noise. Second, spatially filter the image with a difference of Gaussians (DoG) kernel. To detect potential microcalcifications, segment the filtered image using global and local thresholding. Next, cluster and index these detections into regions of interest (ROIs). Identify ROIs on the digitized image (or hardcopy printout) for final radiologic diagnosis.

Development Of A Gel Content Analysis Protocol For Ultra High Molecular Weight Polyethylene, Max Harold Jeanty

Theses

A modified procedure based upon ASTM (D 2765 - 90) to determine the gel content of crosslinked polyethylene plastics was developed. The new procedure was applied to ram extruded Ultra High Molecular Weight (UHMWPE) implant components processed under different manufacturing conditions. This new evaluation tool provides consistent results with greater accuracy and consistency compared to the American Society for the Testing of Materials (ASTM) method. Using the same tool, several relationships between the UHMWPE processing conditions and gel content were established. The amount of gel content is related to the crosslinked material. It has been shown that the more crosslinking …

The In Vitro Evaluation Of Various Biodegradable Composites Used In Internal Fixation Devices, Hui-Chen Hsieh

Theses

In vitro degradation kinetics and mechanical properties of various composites, comprising a polycarbonate (DTE polymer) reinforced with CaP glass fiber, synthetic ceramic and non-ceramic hydroxyapatite (HA-500,OsteoGen HA) were investigated.

They were soaked in the SBF solution with a constant pH of 7.4 at 37°C for 5 days. The DTE/CaP composite degraded in an acid manner such that a large amount of NaOH was required but with a small decrease in calcium ion concentration. By contrast, the DTE/OsteoGen HA composite required comparable amounts of NaOH, but with a concomitantly large decrease in calcium ion concentration. This showed that the OsteoGen HA …

Modeling Of Cardiovascular System To Simulate Ventricular Septal Defect, Adarsh Kumar Gupta

Theses

The hemodynamics of the ventricular septa] defect is studied using a mathematical modeling technique. A twelve-compartment windkessel model of cardiovascular system is used to study the hemodynamics of the ventricular septal defect. The VSD is incorporated into the model via a parallel flow from the left to right ventricles (left-to-right shunt). The resistance to flow through the shunt is used to characterize the severity of the defect. Changes in the severity of the shunt flow produces changes in the ratio of pulmonary to systemic flow in the circulation. When the pulmonary to systemic flow ratio is more than 2:1, the …

Measurement Of The Electroencephalogram (Eeg) Coherence, Atmospheric Noise, And Schumann Resonances In Group Meditation, Douglas A. Newandee

Theses

Electrical activity in the human body was investigated using EEG and ECG measurements while subjects remained with eyes open, eyes closed and in a meditation state. During these measurements, additional antennas were attached to the equipment to record atmospheric noise and signal activity simultaneously. The obtained data was analyzed and various observations were made. Processed data based on antenna signals clearly showed the presence of man-made signals, having narrow spectral widths that could be treated as atmospheric noise in the frequency range up to 50 Hz. In addition, signals clustered around 7.8, 14.1, 20.3, 26.4, and 32.5 Hz were observed …

A Mathematical Model Of Cardiovascular System With Feedback Control, Jiayu Gu

Theses

A mathematical model of human cardiovascular system is presented in this study. The closed-loop model is composed of twenty compartments which includes the left and right ventricles, and the systemic and pulmonary circulations. Two physiologic feedback control mechanisms, autoregulation of blood flow and baroreceptor reflex regulation of arterial pressure, are incorporated in the model. Autoregulation acts by changing local resistance to blood flow through metabolic and myogenic mechanisms, thereby insuring a match between oxygen supply and demand for any tissue or organ. Baroreceptors act through neural pathways to alter heart rate, contractility and peripheral resistance in order to return sudden …

Comparison Of Different Signal Processing Algorithms To Extract The Respiration Waveform From The Ecg, David J. Caggiano

Theses

Power spectral analysis of heart rate variability is a powerful tool to measure the activity of the parasympathetic division of the autonomic nervous system noninvasively. To determine the parasympathetic activity, the frequency of respiration must be known. However, during ambulatory studies, the frequency of respiration is not acquired. To alleviate this problem, methods have been proposed in the past to derive the respiration from the ECG. Unfortunately, these previous methods are unreliable if the subject's breathing rate is uncontrolled. In this study, four methods to derive the respiration waveform from the electrocardiogram (ECG) were developed. Two leads of ECG and …

A New Concept In Artificial Ligament And Tendons Modeling : Finite Element Analysis, Miroslaw Sokol

Theses

Reconstruction of the Anterior Cruciate Ligament (ACL) has been a major focus in sports medicine for over twenty years. Severe or unrepairable damage of the ACL due to sport injury is a major problem faced by orthopedic surgeons and engineers. To successfully replace or reconstruct an injured ACL, the mechanical properties as well as the dimensional limitation of the material used must be similar to the biological ligaments. Although excessive literature describes experimental investigation on the mechanical property and clinical application of the ligament material, there is no analytical study that describes strains, stresses, and endurance in the bone/ligament/bone complex. …

Validation Of A Mathematical Model Of The Human Walking Cycle Using Parameter Identification Methods, Robert Mccann

Theses

A mathematical model of the swing phase, toe-off and heel strike is presented in this paper and is mathematically represented as a two dimensional, simple coupled pendulum system with three degrees of freedom. Lagange equations of motion are used to solve this highly idealized system. The model consists of three segments which represent the stance leg, thigh and shank. During the swing phase it is assumed that the only external forces acting on the system are gravity and viscous dissipative terms proportional to joint angular velocities. It is assumed that muscle forces act only to establish the initial limb segment …

Signal Processing Techniques In Heart Rate And Systolic Arterial Blood Pressure Variability Studies, Christopher O'Bara

Theses

Power spectral analysis of heart rate and systolic arterial blood pressure variability provides a window to the activity of the autonomic nervous system. To derive power spectra from raw blood pressure and electrocardiogram signals, many steps of signal processing must be performed. Most popular methods of spectral analysis require evenly spaced samples; therefore interpolation and resampling techniques must be used.

The results of the present study indicate that different interpolation techniques result in spectral distortions that vary depending upon the interpolation methods used as well as physiological parameters such as heart and respiration rate. Different interpolation methods applied to heart …

A New Device For Performing Simultaneous Sterno-Thoracic Cardiopulmonary Resuscitation (Sst-Cpr), Deepak S. Gupta

Theses and Dissertations

There are two different physiological mechanisms that cause blood to circulate around the human body during cardiopulmonary resuscitation. The "cardiac pump" generates blood flow by squeezing blood out of the heart as the sternum is depressed. The "thoracic pump" generates flow by forcing blood out of the heart and the great vessels as the intrathoracic pressure rises due to chest compression.

To date, all CPR techniques try to circulate blood during cardiac arrest by exploiting elite; the cardiac pump or the thoracic pump mechanism of blood flow. No mechanical CPR device thus far invented has tried to exploit both mechanisms …

Effect Of Light Source On The Sorting Performance Of A Vision-Based Robot System, Johnny T. Li

Dissertations and Theses @ UNI

Industries look toward computer vision as a means to automate materials handling. To make this choice more appealing, useful and feasible vision applications must be explored. However, illuminance variation in the factory environment can undermine the capability and applicability of vision-based control systems. The purposes of this study were (a) to design and develop a vision-based robot material sorting system, (b) to determine the optimal settings for this system under fluorescent and incandescent lighting for two different color parts on a moving conveyor, and (c) to determine the sorting performance of this system under each light source.

The main components …