Master of Science in Biomedical Engineering (MSBME), Wright State University, 2015, Biomedical Engineering

The biophysics of volume conduction that enable electrophysiological data acquisition also result in the mixing of data sources including possible, undesirable noise sources at the electrode interface. This work specifically focuses on improving the performance of the recursive least-squares (RLS) adaptive filtering method for removing eye movement artifact from the electroencephalogram. In biophysically-inspired simulated data, the RLS algorithm is verified to produce results that are inferior to extended infomax independent component analysis (ICA), the most widely used artifact correction approach in this problem space, due to its non-linear filter phase response and the presence of bidirectional contamination, or cross-talk, resultant of volume conduction in electroencephalographic data. The non-linear phase response of the RLS algorithm is mitigated by restricting its filter coefficients to form a linear phase, Type I finite impulse response filter. A reduced effect of cross-talk in RLS is achieved by filtering the reference noise input signal using a combination of non-local means weighting and Bayesian adaptive regression splines smoothing. When compared to extended infomax ICA, the modified RLS adaptive filtering approach meets or exceeds data source recovery accuracy while retaining highly desirable properties not afforded by blind source separation. These results support the use of a modified adaptive filtering approach for the near-ideal removal of eye artifact data from the electroencephalogram.

Committee: Ping He Ph.D. (Advisor); Julie Skipper Ph.D. (Committee Member); Nasser Kashou Ph.D. (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Biophysics; Engineering; Neurosciences

MA, Kent State University, 2014, College of Arts and Sciences / Department of Geography

COAKLEY, CORRINE, M.A. AUGUST 2014 GEOGRAPHY ACTIVITY SPACE IN A TERMINAL CLASSIC MAYA HOUSEHOLD, XEUNKAL, YUCATAN, MEXICO (222 pp) Director of Thesis: Mandy Munro-Stasiuk The Terminal Classic Maya period in the Northern Yucatan was a time of political upheaval, when long established cities such as Uxmal collapsed and Chichen Itza began to rise to power. Xuenkal, a site about 40 km north of Chichen Itza, was located directly on trade routes that would have supplied the city of Chichen Itza with imported goods and prestige items during this transition. Xuenkal itself shows several occupational phases, from a monumental phase during the Classic period, to abandonment, to a third phase in which population expanded during the Terminal Classic and new structures were built upon the former monumental, ritual spaces from the Classic period. These new structures include the subject of this research, Structure 9L-31, a walled complex of three buildings built on the platform of Xuenkal's most impressive structure, Structure 10M-62, the site's Classic period temple. Focusing on the social construction of place and scale, this thesis uses concepts from feminist geography and time geography to determine activity spaces across Structure 9L-31. Household scale analysis includes type variety analysis of the ceramics found at Structure 9L-31 and source and production stage analysis on the lithic artifacts. Through the use of artifact patterns as social behavior proxies, residents' space use and behavioral patterns are explored. Methods used include the use of descriptive statistics, Getis Ord Gi* analysis, and geostatistical prediction surfaces. Specifically, gendered use of space, production and domestic uses of space, and household vs. prestige artifact patterns are examined. Traditional archaeological ceramic analysis is compared to geostatistical techniques to inform upon both practices and answer the question of how the residents of Structure 9L-31 used their space. Re (open full item for complete abstract)

Committee: Mandy Munro-Stasiuk Ph.D. (Advisor); T. Kam Manahan Ph.D (Advisor); Jacqueline Curtis Ph.D. (Committee Member) Subjects: Archaeology; Geographic Information Science; Geography

Master of Computing and Information Systems, Youngstown State University, 2023, Department of Computer Science and Information Systems

Additive Manufacturing (AM), particularly LASER Powder Bed Fusion (LPBF), has gained prominence for its flexibility and precision in handling complex metal structures. However, optimizing L-PBF for intricate designs involves analyzing over 130 process parameters, leading to prolonged duration and increased costs. This thesis proposes a novel approach by harnessing statistical and machine learning algorithms to predict manufacturability issues before the printing process. By performing a comparative analysis of the intended design with the machine produced result, the study introduces two machine learning and one artificial neural network (ANN) algorithm to forecast the printability of new designs accurately. This innovative method aims to reduce or eliminate the need for iterative printing, reducing productivity costs and optimizing the LPBF additive manufacturing process.

Committee: Alina Lazar PhD (Advisor); John R. Sullins PhD (Committee Member); Hunter Taylor PhD (Committee Member) Subjects: Computer Engineering; Computer Science; Engineering; Information Science; Information Systems; Information Technology; Materials Science; Mechanical Engineering

Master of Fine Arts, The Ohio State University, 2023, Design

Sexual and reproductive experiences, often unacknowledged or unspoken, exert a profound influence on various aspects of life, including relationships, careers, and the shape of our mutual futures, particularly for individuals assigned female at birth (AFAB). This research endeavors to explore the transformative potential that emerges when AFAB individuals are granted agency to speculate on the future; imagining, provoking, and dreaming into what could be. The study combined co-design and speculative design approaches to structure collaborative group sessions, during which study participants ultimately created 24 artifacts from the future related to contraception, sexual pleasure, and menstrual cycles; artifacts evidence participants' expressed perspectives on near and far futures. The study also involved focus groups to determine how to share the artifacts, considering questions like who should be invited, how should the artifacts be presented, and what is our intention in sharing? By embracing qualitative research methods, this study delves deep into the nuanced aspects of participants' dreams and fears about the future. The findings emphasize the significance of co-design and speculative design as complementary approaches in design research. They also highlight the capacity of AFAB individuals to imagine diverse and impactful futures beyond what currently exists. The conclusions drawn from this study call for further investigations into the synergistic potential of co-design and speculative design, contributing to a deeper understanding of the role of imagination in shaping future possibilities, particularly for complex, sensitive topics such as sexual and reproductive experiences.

Committee: Elizabeth B.-N. Sanders (Advisor); William Nickley (Committee Member); David Staley (Committee Member) Subjects: Design

Master of Science, The Ohio State University, 2021, Dentistry

Introduction: Cone beam computed tomography (CBCT) has been used to diagnose temporary anchorage device (TAD)-tooth root proximity. Recent literature found CBCT produces high false positive diagnosis of TAD-root contact, likely due to metal artifacts or low CBCT scan resolution. This study aimed to assess whether CBCT diagnosis of TAD-root contact can be improved by applying an artifact reduction algorithm (ARA) or increasing CBCT scan resolution. Methods: Eighteen fresh pig cadaver mandibles were used. TADs were placed below first molar lingual furcation on both sides. CBCT scans were taken at 0.4mm voxels with and without ARA application, followed by 0.2mm voxels with and without ARA. Then, TADs were removed and a micro-CT scan (27-micron voxel size) of the TAD placement site was performed. Two blinded raters analyzed CBCT and micro-CT images independently. Subsequently, CBCT diagnostic reliability and accuracy were assessed, using micro-CT as gold standard. Results: Cohen's kappa tests showed moderate to strong intra-rater and inter-rater reliability of CBCT diagnoses. For CBCT diagnostic accuracy, there was a higher false positive rate (8-24%) than false negative rate (0-9%). McNemar tests revealed ARA application significantly decreased false positive rate on 0.4mm voxel size CBCT scans (from 24% to 8%, p<0.05) in one rater but not the other. Decreasing CBCT voxel size to 0.2mm produced insignificant diagnostic improvement over 0.4mm voxels in both raters. Conclusions: CBCT diagnosis of TAD-root contact with 0.4mm voxels is reasonably reliable and accurate with diagnostic error stemming from false positive diagnosis. False positive diagnosis may improve with ARA application.

Committee: Zongyang Sun (Advisor); Sonya Kalim (Committee Member); Do-Gyoon Kim (Committee Member) Subjects: Dentistry

MA, University of Cincinnati, 2020, Arts and Sciences: Anthropology

Within the field of Mesoamerican archaeology, research on ancient marketplaces, where important economic transactions took place often in large open plaza areas, is just beginning to expand. The Maya, who lived in Central America and Southern Mexico from 250-900 AD in the Classic Period, used such plaza spaces to purchase, barter, and trade every day and ceremonial items such as food, tools, and pottery. My research focuses on the Late Classic plaza at Group D at the site of Say Kah, located in the Three Rivers region of Belize, Central America. The methodology for this thesis is modeled after a newer method which uses one of the signatures of a marketplace: distinct clusters of artifacts. These clusters, when compared to other lines of evidence, such as soil chemistry, can suggest stall-like or linear patterning indicative of a marketplace. Though the analysis of the distribution of ceramic and lithic artifacts, using chi-square tests and the Global Moran's I formula, from the Group D plaza does not suggest a marketplace at this time, the results emphasize the need to find new methodological ways to overcome the issue of the preservation of perishable objects in marketplace research in order to better understand these activities.

Committee: Sarah Jackson Ph.D. (Committee Chair); Susan Allen Ph.D. (Committee Member); Jeffrey Brewer Ph.D. (Committee Member) Subjects: Archaeology

MFA, Kent State University, 2020, College of the Arts / School of Art

The Sacred Transfigured are the cumulative results of researching textile processes as sacred ritual resulting in artifacts that can be engaged in a participatory manner by the viewer. Questions I aim to resolve through the artworks presented are: Why are textiles special? How can material like wool and linen be transfigured into precious artifacts? What about this construction process is sacred? What is the role of the artist in that process? These questions are explored through weaving, felting and stitching specifically to examine the unique and magic qualities of textiles that can serve as tools of communication between artist and viewer. The artifacts presented are both precious objects and theatrical garments serving to heighten the senses of the viewer and help construct a certain aura around the wearer.

Committee: Janice Lessman-Moss (Advisor); Isabel Farnsworth (Committee Member); Andrew Kuebeck (Committee Member) Subjects: Fine Arts; Performing Arts; Textile Research

Doctor of Philosophy, Case Western Reserve University, 2018, Biomedical Engineering

Functional Electrical Stimulation (FES) is an assistive technology that uses stimulating electrodes to reanimate muscles and restore lost functions to people with tetraplegia. Brain-computer interfaces (BCIs), which decode recorded neural activity into user commands, are an enticing technology for commanding assistive devices because they can extract multiple command signals even in the absence of movement. This work, through the BrainGate2 pilot clinical trial, makes progress towards restoring brain-controlled arm and hand movements after paralysis through three main advancements in the development of a combined FES+BCI system. First, we show that FES stimulation produces electrical artifacts on intracortical recordings that significantly degrades BCI performance, particularly in the case of surface FES. However, we present a novel artifact reduction method, linear regression reference, which extracts meaningful information during both implanted and surface FES periods and fully restores normal BCI performance. Second, we compare two potential interfaces for control of human arm reaching: Cartesian and joint based commands. In a virtual reaching and posture matching task, we analyze neural tuning differences between the conditions and show significantly higher performance when using the standard Cartesian commands. Third, we implement the first BCI control of an implanted FES system for restoring four dimensions of arm and hand movement. We show evidence that neural activity is largely similar between control of real and virtual movements, and demonstrate similar performance in FES tasks compared to virtual training. We make progress towards restoring brain-controlled movement after paralysis through improvements in three components of an FES+BCI system: the signal processing, command interface, and effector. Our work culminates in a demonstration of functional performance through one participant's consistent success in self-initiated activities of dail (open full item for complete abstract)

Committee: A. Bolu Ajiboye PhD (Advisor); Robert Kirsch PhD (Committee Chair); Dawn Taylor PhD (Committee Member); Jonathan Miller MD (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Rehabilitation

Doctor of Philosophy, The Ohio State University, 2015, Electrical and Computer Engineering

In vivo imaging provides a venue for studying and understanding the biological mechanism of a living system noninvasively. High resolution scanning for MR imaging is practically limited by the length of the scan for in vivo applications. In vivo small animal MRI suffers from subject motion which can degrade image quality with blurring and artifacts. In many small animal imaging studies, multiple imaging views are already obtained as part of the normal workflow but the information taken from one view is not generally combined with that from another view. The main objective of this dissertation is to study the use of multiple imaging views for improving image quality in small animal MR imaging studies. The goal of the study is to evaluate post-processing techniques that could make use of multiple low resolution image acquisitions for increasing resolution in through-plane 3D images and to reduce motion artifacts in in-plane 2D images. Both qualitative and quantitative comparisons are carried out to evaluate the performance of the algorithms and they are demonstrated in in vivo settings.

Committee: Bradley Clymer PhD (Advisor); Kimerly Powell PhD (Advisor); Can Koksal PhD (Committee Member) Subjects: Electrical Engineering

Master of Science in Biomedical Engineering (MSBME), Wright State University, 2015, Biomedical Engineering

Non-contact imaging photoplethysmography is an exciting new field based on the principles of traditional photoplethysmography where viable signals can now be acquired without the use of contact equipment. Recent advances regarding non-contact imaging photoplethysmography have permitted a wide range of new possibilities focused on sensing the cardiopulmonary system. Physiological metrics such as pulse rate, respiration rate, and pulse rate variability can be obtained by current photoplethysmographic imaging methods. Although previous systems were challenged by head-motion artifacts, the mitigation of rigid head-motion artifacts has been demonstrated with a multi-imager design. This study investigated the feasibility and accuracy of pulse rate variability utilizing a multi-imager recording system. Parameters such as sampling rate, image resolution, and number of imagers utilized were examined in an attempt to minimize overall system data bandwidth. Accurate pulse rate variability metrics where found within the frequency and temporal domains, along with promising results regarding the aforementioned input parameters.

Committee: Mary Fendley Ph.D. (Advisor); Nasser Kashou Ph.D. (Committee Member); Phani Kidambi Ph.D. (Committee Member) Subjects: Biomedical Engineering; Biomedical Research

Doctor of Philosophy, Case Western Reserve University, 2015, EECS - Electrical Engineering

A stimulus artifact rejection (SAR) system has been developed for performing artifact removal from contaminated neural data in real time (i.e., as the recording is taking place). The SAR algorithm is first developed for hardware implementation and prototyped in a field-programmable gate array (FPGA) platform. The design is then implemented in AMS 0.35µm two-poly four-metal (2P/4M) CMOS technology and integrated with neural-recording and microstimulation circuitry into a 3.1 × 3.1-mm2 chip to create a functional, standalone neural interface microsystem with recording, stimulation, and real-time SAR capability. The SAR algorithm along with its system- and circuit-level architecture, as well as experimental results from benchtop and neurobiological testing of the neural interface microsystem are presented and discussed.

Committee: Pedram Mohseni (Committee Chair); Hillel Chiel (Committee Member); Marc Buchner (Committee Member); Swarup Bhunia (Committee Member) Subjects: Electrical Engineering

Master of Science, The Ohio State University, 2013, Dentistry

ABSTRACT Introduction: Cancer is still the second cause of death worldwide with head and neck cancer being about 3% of the total number of diagnosed cases. Surgery is still one of the most effective treatment modalities. It often causes debilitating morbidity to the oral-pharyngeal structures. Currently, certain cases are being treated primarily with radiation and/or chemoradiation since the outcomes when compared to surgery are similar. When high-energy radiation (photons) interact with electron-dense materials. Secondary electrons are produced from radiation interaction with materials such as metals, which is termed “Radiation backscatter”. This results in adjacent tissues receiving an additional, unintended dose. And the visual artifacts that caused by them during CT scanning adversely affect the quality of the scan and its diagnostic value. Research has been done in the past to determine the amount of radiation backscatter caused by various dental materials and it was determined that gold and gold alloys causes the most scatter followed by amalgam and titanium respectively. The use of Zirconium has increased significantly in medicine and dentistry during the past forty years. It was first introduced in medical prosthetics in 1969 as an orthopedic hip replacement implants. Currently, Zirconia restorations are a large percentage of the dental marketplace. There has been a great increase in the demand for zirconia-based restorations, both by patients, and dentists. Aggressive marketing programs for more esthetically pleasing restorations have driven this demand. The aim of our study is to compare dose enhancement factor/ backscatter of Zirconia to other commonly used dental materials. Due to the density of Zirconia compared to other previously testes dental materials we hypothesize that there is a decrease in dose enhancement around Zirconia compared to Gold and Amalgam and an increase in dose enhancement when compared to (open full item for complete abstract)

Committee: Robert Seghi (Advisor) Subjects: Dentistry; Health Care; Health Sciences; Materials Science; Medical Imaging; Physics; Radiation

Master of Science in Engineering (MSEgr), Wright State University, 2012, Biomedical Engineering

In computed tomography (CT) systems, many different artifacts may be present in the reconstructed image. These artifacts can greatly reduce image quality. For our laboratory prototype CT system, a fan-beam/cone-beam focal high-resolution computed tomography (fHRCT) scanner, the major artifacts that affect image quality are distortions due to errors in the reconstruction algorithm's geometric parameters, ring artifacts caused by uncalibrated detectors, cupping and streaking created by beam hardening, and patient-based motion artifacts. Optimization of the system was required to reduce the effects of the first three artifact types, and an algorithm for correction of translational motion was developed for the last. System optimization of the system occurred in three parts. First, a multi-step process was developed to determine the geometric parameters of the scanner. The ability of the source-detector gantry to translate allowed a precise method to be created for calculating these parameters. Second, a general flat-field correction was used to linearize the detectors and reduce the ring artifacts. Lastly, beam hardening artifacts were decreased by a preprocessing technique. This technique assumes linear proportionality between the thickness of the calibration material, aluminum, and the experimental measurement of ln(No/N), where No is the total number of photons entering the material and N is the number of photons exiting the material. In addition to system optimization to minimize artifacts, an algorithm for correction of translational motion was developed and implemented. In this method, the integral mass and center of mass at each projection angle was seen to follow a sinusoidal or sinusoidal-like curve. Fits were used on the motion-encoded sinograms to determine both of these curves and, consequently, the amount and direction of motion that occurred. Each projection was individually adjusted to compensate for this motion by widening or narrowing the projection bas (open full item for complete abstract)

Committee: Thomas Hangartner PhD (Advisor); David Short MS (Committee Member); Julie Skipper PhD (Committee Member) Subjects: Biomedical Engineering

MA, University of Cincinnati, 2012, Arts and Sciences: Anthropology

Several competing models and interpretations regarding sherd-and-lithic artifact scatters in the American Southwest are topics of debate among archaeologists. The limitations of many of these models have been postulated to be caused, in part, by the use of inappropriate units of analysis, such as the “limited-activity site” taxon, and non-standard sampling procedures. By using the Upper Basin Archaeological Research project's Mapping Unit (MU) concept, this study explores potential sources of inter-class and intra-class variability. In order to analyze possible sources of inter-class variability, sherd-and-lithic artifact scatters are compared to all other types of Mapping Units through spatial and statistical analysis. Additionally, this study investigates artifact assemblage data from a sample of 42 sherd-and-lithic artifact scatters in order to evaluate potential sources of intra-class variability. In both analyses, a special emphasis is placed on comparison between sherd-and-lithic artifact scatters that exist independently of architecture, versus those that are associated with architecture. Through these analyses, competing models are evaluated and new interpretations are formed regarding the role of sherd-and-lithic artifact scatters in larger regional settlement and subsistence models.

Committee: Alan Sullivan PhD (Committee Chair); Vernon Scarborough PhD (Committee Member) Subjects: Archaeology

MS, University of Cincinnati, 2008, Medicine : Radiology-Radiological Sciences (Medical Physics)

The presence of image "blooming" artifacts, in particular with respect to highly calcifiedplaques, has been a major impediment to the implementation of Multi-detector Computed Tomography (MD-CT) as an alternative to standard angiography in routine clinical practice. A beam hardening phantom system was developed to determine the dependence of blooming with respect to measured density in Hounsfield Units (HU), of 5mm diameter plaques. Custom software was developed to provide reproducible objective measurements of plaque size. Plaque diameter was measured using a series of axially distributed profiles centered on the object. Reconstruction blur was shown to be a significant, density dependent contributor to standard clinical blooming measurements. Beam hardening was shown to not affect measurements of sample diameter in a blur corrected study. Furthermore, two additional phantom designs have been proposed and evaluated for the future study of partial volume and cone beam affects on blooming.

Committee: Lisa Lemen PhD (Committee Chair); Elson Howard PhD (Committee Member); Lamba Michael PhD (Committee Member) Subjects: Radiation; Radiology; Scientific Imaging

Master of Sciences (Engineering), Case Western Reserve University, 2008, Electrical Engineering and Computer Science - Electrical Engineering

Due to their large amplitudes, stimulus artifacts can easily saturate neural recording amplifiers and hamper neural signal analysis during recording. In this work, we present a prototype stimulus artifact rejection (SAR) system, which is based on the template subtraction technique. A reference template signal of the stimulus artifact is generated by a pseudo-higher sampling rate averaging method, which is then subtracted from the original contaminated signal to reveal the desired neural activity. Measurement results from a proof-of-concept discrete implementation of the SAR system indicate that it is highly effective in reducing the amplitude of the stimulus artifacts. The system exhibits a stimulus artifact rejection of ~10-15 dB at the rising and falling edges of the artifact (where it is changing rapidly with time) and successfully recovers microvolt-range neural action potentials from the slowly decaying tail of the artifact. Compared to the existing subtraction-based SAR algorithms, additional stimulus artifact suppression of ~5.5 dB is achieved in this work.

Committee: Pedram Mohseni (Committee Chair); Frank Merat (Other); Marc Buchner (Other) Subjects:

Master of Arts, University of Akron, 2011, Theatre Arts-Arts Administration

Standards are set by conservators as to the ideal conditions in which artifacts are stored and displayed. These standards provide for the preservation of museum objects that, if left alone and vulnerable to the environment, would deteriorate at a much faster rate. Unfortunately, using all ideal materials in storage and exhibit case construction is not within the budget for most small to medium sized museums. Therefore, adaptations from the standards should be made dependent on museum resources on a case-to-case basis. This paper is focused on the construction of exhibit cases and galleries to fit conservation standards and addresses the objects displayed, materials used to construct display cases, the role these materials play in the preservation of objects, and less expensive alternatives. For the purpose of this project, the focus is on museum objects and needs of the Pro Football Hall of Fame, National Football Museum, LLC in Canton, Ohio. This paper is broken into five areas that cover the different concerns in the creation of conservation quality exhibits. The first chapter, “Care of Objects”, covers the different materials that make up museum objects in this museum and the specific concerns regarding the degradation of materials. The second chapter, “Environmental Control of Objects on Exhibit”, addresses safe and not-so-safe lighting options, how light is damaging to materials, interior case lighting versus exterior case lighting, temperature and relative humidity, and dangers of airborne pollutants. A chapter on “Safe Exhibit Case Construction Materials” covers what building materials should be used and those that should be avoided. “Exhibit Case Design and Security” explains the different case styles, case access, and security principles that should be taken into account when designing exhibit cases for museum objects. “Sealed vs. Ventilated Exhibit Cases” explores the difference between these two types of exhibit cases and when each style is more approp (open full item for complete abstract)

Committee: Durand Pope Mr. (Advisor); Rod Bengston Mr. (Committee Member); Jason Aikens Mr. (Committee Member) Subjects: American History; Archaeology; Arts Management; Conservation; Design; Fine Arts; History; Modern History; Museum Studies; Museums; Sports Management

Master of Science in Engineering, University of Akron, 2008, Biomedical Engineering

Electroencephalogram (EEG) signals, when recorded within the strong magnetic field of an MR scanner, are subject to various artifacts, of which the ballistocardiogram (BCG) is one of the prominent artifacts affecting the quality of the EEG. The BCG is continuously varying with time and its spectrum overlaps with the EEG spectra, making its suppression a signal processing challenge. A novel method for the identification and removal of this artifact using shape basis functions of the new dilated discrete Hermite transform is investigated in this paper. The BCG artifacts are modeled for every heart beat, using these discrete Hermite basis functions, and are subsequently subtracted from the ongoing EEG. Experimental EEG data was recorded inside and outside a 3 Tesla MRI scanner, from a total of 7 subjects under various experimental conditions. Quantitative assessment of the efficiency of this algorithm was evaluated by adding known BCG templates, at varying Signal to Noise Ratios (SNRs), to the EEG recorded outside the scanner. Significant reduction of the BCG artifact (p<0.05) was obtained without distortion of the underlying EEG signal. This method was compared with current BCG artifact removal techniques using EEG data recorded within the scanner field and its performance was found to be better than the Average Artifact Subtraction (AAS) method and had comparable results to the Independent Component Analysis (ICA) based methods. Real time implementation of the algorithm is possible due to the ease of computations.

Committee: Dale H. Mugler PhD (Advisor) Subjects: Biomedical Research

Doctor of Philosophy, Case Western Reserve University, 2013, Biomedical Engineering

There exist an extraordinary number of ways to create an MR image, and the number seems to grow daily. In almost all cases, images will be viewed by radiologists to make a diagnosis, to stage a disease, to apply a treatment, and/or to assess a treatment. Since images are viewed, one needs to assess visual image quality, preferably in a quantitative way. We developed a perceptual difference model, Case-PDM, to quantitatively assess image quality, in a way well-correlated to clinical needs, and demonstrate how the methods can be used to improve MR imaging techniques. We validated existing Case-PDM with advanced observer experiments. Human evaluation of MR images from multiple organs and from multiple image reconstruction algorithms were compared to Case-PDM and competing methods such as IDM (Sarnoff Corporation) and SSIM (Wang et al.). Global image quality is quantified by comparing fast acquired, reconstructed image to slower, full k-space, high quality reference image. We used advanced human observer experimental methods (DSCQS, FMT, 2AFC) to prove these methods on the contexts of human-model correlation, comparability of model evaluation scores across different image contents, and imperceptible difference threshold discrimination. To date, most objective image quality metrics average over a wide range of image degradations. However, human clinicians demonstrate bias toward different types of artifacts. We used an advanced observer experiment and Artifact-PDM, an extension of Case-PDM, to measure relative disturbance of MR image artifacts to radiologists. We used a Functional Measurement Theory (FMT) pair-comparison experiment to measure the disturbance of each artifact to human observers. Radiologists showed preferences towards particular image artifacts, the relative disturbances of which can be quantitatively measured by both observer study and Artifact-PDM. We also applied our methodology to a novel MRI reconstruction algorithm, such as Compressed Sensing (CS) w (open full item for complete abstract)

Committee: David Wilson PhD (Advisor); Xin Yu ScD (Committee Member); Mark Griswold PhD (Committee Member); Grover Gilmore PhD (Committee Member) Subjects: Biomedical Engineering; Medical Imaging