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Biomedical Engineering Faculty Research and Publications

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Full-Text Articles in Biomedical Engineering and Bioengineering

Effects Of Training Intensity On Locomotor Performance In Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study, Gabrielle Brazg, Meghan Fahey, Carey L. Holleran, Mark Connolly, Jane Woodward, Patrick W. Hennessy, Brian D. Schmit, T. George Hornby Jan 2017

Effects Of Training Intensity On Locomotor Performance In Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study, Gabrielle Brazg, Meghan Fahey, Carey L. Holleran, Mark Connolly, Jane Woodward, Patrick W. Hennessy, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

Background. Many physical interventions can improve locomotor function in individuals with motor incomplete spinal cord injury (iSCI), although the training parameters that maximize recovery are not clear. Previous studies in individuals with other neurologic injuries suggest the intensity of locomotor training (LT) may positively influence walking outcomes. However, the effects of intensity during training of individuals with iSCI have not been tested. Objective. The purpose of this pilot, blinded-assessor randomized trial was to evaluate the effects of LT intensity on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI >1 year duration performed either …


How A Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review Of Nidilrr’S Rehabilitation Engineering Research Centers, David J. Reinkensmeyer, Sarah Blackstone, Cathy Bodine, John Brabyn, David Brienza, Kevin Caves, Frank Deruyter, Edmund Durfee, Stefania Fatone, Geoff Fernie, Steven Gard, Patricia Karg, Todd A. Kuiken, Gerald F. Harris, Mike Jones, Yue Li, Jordana Maisel, Michael Mccue, Michelle A. Meade, Helena Mitchell, Tracy L. Mitzner, James L. Patton, Philip S. Requejo, James H. Rimmer, Wendy A. Rogers, W. Zev Rymer, Jon A. Sanford, Lawrence Schneider, Levin Sliker, Stephen Sprigle, Aaron Steinfeld, Edward Steinfeld, Gregg Vanderheiden, Carolee Winstein, Li-Qun Zhang, Thomas Corfman Jan 2017

How A Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review Of Nidilrr’S Rehabilitation Engineering Research Centers, David J. Reinkensmeyer, Sarah Blackstone, Cathy Bodine, John Brabyn, David Brienza, Kevin Caves, Frank Deruyter, Edmund Durfee, Stefania Fatone, Geoff Fernie, Steven Gard, Patricia Karg, Todd A. Kuiken, Gerald F. Harris, Mike Jones, Yue Li, Jordana Maisel, Michael Mccue, Michelle A. Meade, Helena Mitchell, Tracy L. Mitzner, James L. Patton, Philip S. Requejo, James H. Rimmer, Wendy A. Rogers, W. Zev Rymer, Jon A. Sanford, Lawrence Schneider, Levin Sliker, Stephen Sprigle, Aaron Steinfeld, Edward Steinfeld, Gregg Vanderheiden, Carolee Winstein, Li-Qun Zhang, Thomas Corfman

Biomedical Engineering Faculty Research and Publications

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their …


Multimodal Imaging Of Photoreceptor Structure In Choroideremia, Lynn W. Sun, Ryan D. Johnson, Vesper Williams, Phyllis Summerfelt, Alfredo Dubra, David V. Weinberg, Kimberly E. Stepien, Gerald A. Fishman, Joseph Carroll Dec 2016

Multimodal Imaging Of Photoreceptor Structure In Choroideremia, Lynn W. Sun, Ryan D. Johnson, Vesper Williams, Phyllis Summerfelt, Alfredo Dubra, David V. Weinberg, Kimberly E. Stepien, Gerald A. Fishman, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose

Choroideremia is a progressive X-linked recessive dystrophy, characterized by degeneration of the retinal pigment epithelium (RPE), choroid, choriocapillaris, and photoreceptors. We examined photoreceptor structure in a series of subjects with choroideremia with particular attention to areas bordering atrophic lesions.

Methods

Twelve males with clinically-diagnosed choroideremia and confirmed hemizygous mutations in the CHM gene were examined. High-resolution images of the retina were obtained using spectral domain optical coherence tomography (SD-OCT) and both confocal and non-confocal split-detector adaptive optics scanning light ophthalmoscope (AOSLO) techniques.

Results

Eleven CHM gene mutations (3 novel) were identified; three subjects had the same mutation and one …


Repeat Exposure To Leg Swing Perturbations During Treadmill Training Induces Long-Term Retention Of Increased Step Length In Human Sci: A Pilot Randomized Controlled Study, Ming Wu, Jill M. Landry, Janis Kim, Brian D. Schmit, Sheng-Che Yen, Jillian Mcdonald, Yunhui Zhang Dec 2016

Repeat Exposure To Leg Swing Perturbations During Treadmill Training Induces Long-Term Retention Of Increased Step Length In Human Sci: A Pilot Randomized Controlled Study, Ming Wu, Jill M. Landry, Janis Kim, Brian D. Schmit, Sheng-Che Yen, Jillian Mcdonald, Yunhui Zhang

Biomedical Engineering Faculty Research and Publications

Objective: To determine whether repeat exposure to force perturbations during treadmill training can induce long-term retention of improved step length and overall improvements in locomotor function in persons with spinal cord injury.

Design: Fourteen patients with spinal cord injury were recruited and randomly assigned to swing resistance or swing assistance training groups. A controlled swing resistance or assistance force, for resistance or assistance training groups, respectively, was applied to both legs through a cable-driven robotic system during treadmill training. Each participant trained 3 times per week for 6 weeks. Step length, walking speed, 6-minute walking distance, and other clinical assessments …


Transient Local Bone Remodeling Effects Of Rhbmp-2 In An Ovine Interbody Spine Fusion Model, Hyun W. Bae, Vikas V. Patel, Zeeshan M. Sardar, Jeffrey Badura, Ben B. Pradhan, Howard Seim, Anthony S. Turner, Jeffrey M. Toth Dec 2016

Transient Local Bone Remodeling Effects Of Rhbmp-2 In An Ovine Interbody Spine Fusion Model, Hyun W. Bae, Vikas V. Patel, Zeeshan M. Sardar, Jeffrey Badura, Ben B. Pradhan, Howard Seim, Anthony S. Turner, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a powerful osteoinductive morphogen capable of stimulating the migration of mesenchymal stem cells (MSCs) to the site of implantation and inducing the proliferation and differentiation of these MSCs into osteoblasts. Vertebral end-plate and vertebral body resorption has been reported after interbody fusion with high doses of rhBMP-2. In this study, we investigated the effects of 2 rhBMP-2 doses on peri-implant bone resorption and bone remodeling at 7 time points in an end-plate-sparing ovine interbody fusion model. Methods: Twenty-one female sheep underwent an end-plate-sparing discectomy followed by interbody fusion at L2-L3 and L4-L5 …


Accuracy Of Patient-Specific Organ Dose Estimates Obtained Using An Automated Image Segmentation Algorithm, Taly Gilat-Schmidt, Adam S. Wang, Thomas Coradi, Benjamin Haas, Josh Star-Lack Nov 2016

Accuracy Of Patient-Specific Organ Dose Estimates Obtained Using An Automated Image Segmentation Algorithm, Taly Gilat-Schmidt, Adam S. Wang, Thomas Coradi, Benjamin Haas, Josh Star-Lack

Biomedical Engineering Faculty Research and Publications

The overall goal of this work is to develop a rapid, accurate, and automated software tool to estimate patient-specific organ doses from computed tomography (CT) scans using simulations to generate dose maps combined with automated segmentation algorithms. This work quantified the accuracy of organ dose estimates obtained by an automated segmentation algorithm. We hypothesized that the autosegmentation algorithm is sufficiently accurate to provide organ dose estimates, since small errors delineating organ boundaries will have minimal effect when computing mean organ dose. A leave-one-out validation study of the automated algorithm was performed with 20 head-neck CT scans expertly segmented into nine …


Effect Of Surgical Fusion On Volitional Weight-Shifting In Individuals With Adolescent Idiopathic Scoliosis, Nikhil T. Kurapati, Joseph Krzak, Adam Graf, Sahar Hassani, Sergey Tarima, Peter F. Sturm, Kim W. Hammerberg, Purnendu Gupta, Gerald F. Harris Nov 2016

Effect Of Surgical Fusion On Volitional Weight-Shifting In Individuals With Adolescent Idiopathic Scoliosis, Nikhil T. Kurapati, Joseph Krzak, Adam Graf, Sahar Hassani, Sergey Tarima, Peter F. Sturm, Kim W. Hammerberg, Purnendu Gupta, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Study Design

Prospective.

Objectives

The goals of this study were to (1) evaluate the differences in weightbearing symmetry between individuals with adolescent idiopathic scoliosis (AIS) and typically developing controls; (2) observe the effect of posterior spinal fusion and instrumentation (PSFI) on volitional weight-shifting at 1 and 2 years postoperatively; and (3) evaluate whether lowest instrumented fusion level (ie, lowest instrumented vertebra [LIV]) in PSFI has an effect on volitional weight-shifting.

Summary of Background Data

Previous studies have conflicting findings with regard to the effect of scoliosis on postural control tasks as well as the effect of surgery. They have also …


99mtc-Hexamethylpropyleneamine Oxime Imaging For Early Detection Of Acute Lung Injury In Rats Exposed To Hyperoxia Or Lipopolysaccharide Treatment, Said H. Audi, Anne V. Clough, Steven T. Haworth, Meetha Medhora, Mahsa Ranji, John C. Densmore, Elizabeth R. Jacobs Oct 2016

99mtc-Hexamethylpropyleneamine Oxime Imaging For Early Detection Of Acute Lung Injury In Rats Exposed To Hyperoxia Or Lipopolysaccharide Treatment, Said H. Audi, Anne V. Clough, Steven T. Haworth, Meetha Medhora, Mahsa Ranji, John C. Densmore, Elizabeth R. Jacobs

Biomedical Engineering Faculty Research and Publications

99mTc-Hexamethylpropyleneamine oxime (HMPAO) is a clinical single-photon emission computed tomography biomarker of tissue oxidoreductive state. Our objective was to investigate whether HMPAO lung uptake can serve as a preclinical marker of lung injury in two well-established rat models of human acute lung injury (ALI).

Rats were exposed to >95% O2 (hyperoxia) or treated with intratracheal lipopolysaccharide (LPS), with first endpoints obtained 24 h later. HMPAO was administered intravenously before and after treatment with the glutathione-depleting agent diethyl maleate (DEM), scintigraphy images were acquired, and HMPAO lung uptake was quantified from the images. We also measured breathing rates, heart …


Photoreceptor Inner Segment Morphology In Best Vitelliform Macular Dystrophy, Drew Scoles, Yusufu N. Sulai, Robert F. Cooper, Brian P. Higgins, Ryan D. Johnson, Joseph Carroll, Alfredo Dubra, Kimberly E. Stepien Oct 2016

Photoreceptor Inner Segment Morphology In Best Vitelliform Macular Dystrophy, Drew Scoles, Yusufu N. Sulai, Robert F. Cooper, Brian P. Higgins, Ryan D. Johnson, Joseph Carroll, Alfredo Dubra, Kimberly E. Stepien

Biomedical Engineering Faculty Research and Publications

PURPOSE

To characterize outer retina structure in best vitelliform macular dystrophy (BVMD) and to determine the effect of macular lesions on overlying and adjacent photoreceptors.

METHODS

Five individuals with BVMD were followed prospectively with spectral domain optical coherence tomography and confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). The AOSLO cone photoreceptor mosaic images were obtained within and around retinal lesions. Cone density was measured inside and outside lesions. In 2 subjects, densities were compared with published measurements acquired ∼2.5 years before. One subject was imaged 3 times over a 5-month period.

RESULTS

The AOSLO imaging demonstrated that …


Technology-Assisted Stroke Rehabilitation In Mexico: A Pilot Randomized Trial Comparing Traditional Therapy To Circuit Training In A Robot/Technology-Assisted Therapy Gym, Karla Bustamante Valles, Sandra Montes, Maria De Jesus Madrigal, Adan Burciaga, María Elena Martínez, Michelle J. Johnson Sep 2016

Technology-Assisted Stroke Rehabilitation In Mexico: A Pilot Randomized Trial Comparing Traditional Therapy To Circuit Training In A Robot/Technology-Assisted Therapy Gym, Karla Bustamante Valles, Sandra Montes, Maria De Jesus Madrigal, Adan Burciaga, María Elena Martínez, Michelle J. Johnson

Biomedical Engineering Faculty Research and Publications

Background

Stroke rehabilitation in low- and middle-income countries, such as Mexico, is often hampered by lack of clinical resources and funding. To provide a cost-effective solution for comprehensive post-stroke rehabilitation that can alleviate the need for one-on-one physical or occupational therapy, in lower and upper extremities, we proposed and implemented a technology-assisted rehabilitation gymnasium in Chihuahua, Mexico. The Gymnasium for Robotic Rehabilitation (Robot Gym) consisted of low- and high-tech systems for upper and lower limb rehabilitation. Our hypothesis is that the Robot Gym can provide a cost- and labor-efficient alternative for post-stroke rehabilitation, while being more or as effective as …


Monitoring Of Tissue Optical Properties During Thermal Coagulation Of Ex Vivo Tissues, Vivek K. Nagarajan, Bing Yu Sep 2016

Monitoring Of Tissue Optical Properties During Thermal Coagulation Of Ex Vivo Tissues, Vivek K. Nagarajan, Bing Yu

Biomedical Engineering Faculty Research and Publications

Background and Objective

Real-time monitoring of tissue status during thermal ablation of tumors is critical to ensure complete destruction of tumor mass, while avoiding tissue charring and excessive damage to normal tissues. Currently, magnetic resonance thermometry (MRT), along with magnetic resonance imaging (MRI), is the most commonly used technique for monitoring and assessing thermal ablation process in soft tissues. MRT/MRI is very expensive, bulky, and often subject to motion artifacts. On the other hand, light propagation within tissue is sensitive to changes in tissue microstructure and physiology which could be used to directly quantify the extent of tissue damage. Furthermore, …


Segmental Kinematic Analysis Of Planovalgus Feet In Children With Cerebral Palsy, K. Kruger, K. Konop, Joseph Krzak, Adam Graf, Gerald F. Harris Sep 2016

Segmental Kinematic Analysis Of Planovalgus Feet In Children With Cerebral Palsy, K. Kruger, K. Konop, Joseph Krzak, Adam Graf, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.


Augmenting Sensorimotor Control Using “Goal-Aware” Vibrotactile Stimulation During Reaching And Manipulation Behaviors, Emmanouil Tzorakoleftherakis, Todd D. Murphey, Robert A. Scheidt Aug 2016

Augmenting Sensorimotor Control Using “Goal-Aware” Vibrotactile Stimulation During Reaching And Manipulation Behaviors, Emmanouil Tzorakoleftherakis, Todd D. Murphey, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We describe two sets of experiments that examine the ability of vibrotactile encoding of simple position error and combined object states (calculated from an optimal controller) to enhance performance of reaching and manipulation tasks in healthy human adults. The goal of the first experiment (tracking) was to follow a moving target with a cursor on a computer screen. Visual and/or vibrotactile cues were provided in this experiment, and vibrotactile feedback was redundant with visual feedback in that it did not encode any information above and beyond what was already available via vision. After only 10 minutes of practice using vibrotactile …


Co-Ops And Capstone Design: Are They Interchangeable?, Jay R. Goldberg Jul 2016

Co-Ops And Capstone Design: Are They Interchangeable?, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Many engineering schools in the United States provide opportunities for their undergraduate students to gain practical, real-world experience in their chosen disciplines. Cooperative education is a structured method of combining classroom-based education with practical work experience. A cooperative education experience, commonly known as a co-op, provides academic credit (and pay) for such an experience. Discusses the benefits of these working experiences, focusing on capstone design courses.


Attenuation Of The Ganglion Cell Layer In A Premature Infant Revealed With Handheld Spectral Domain Optical Coherence Tomography, Mara R. Goldberg, Fouad R. Zakka, Joseph Carroll, Deborah M. Costakos Jul 2016

Attenuation Of The Ganglion Cell Layer In A Premature Infant Revealed With Handheld Spectral Domain Optical Coherence Tomography, Mara R. Goldberg, Fouad R. Zakka, Joseph Carroll, Deborah M. Costakos

Biomedical Engineering Faculty Research and Publications

Purpose: To report on subclinical retinal abnormalities shown through handheld spectral domain optical coherence tomography on a premature infant.

Methods: Case report.

Results: The initial and follow-up exams on a premature infant revealed severely attenuated ganglion cell and nerve fiber layers. There was cystoid macular edema in both eyes at the initial visits, which resolved by the 1-year follow-up.

Discussion: Optical coherence tomography can reveal significant retinal abnormalities in premature infants which are not detectable through funduscopic exam. Documenting such findings may be useful for the comprehensive management of vision problems in children with a history of premature birth.


Evaluating Descriptive Metrics Of The Human Cone Mosaic, Robert F. Cooper, Melissa A. Wilk, Sergey Tarima, Joseph Carroll Jun 2016

Evaluating Descriptive Metrics Of The Human Cone Mosaic, Robert F. Cooper, Melissa A. Wilk, Sergey Tarima, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose: To evaluate how metrics used to describe the cone mosaic change in response to simulated photoreceptor undersampling (i.e., cell loss or misidentification).

Methods: Using an adaptive optics ophthalmoscope, we acquired images of the cone mosaic from the center of fixation to 10° along the temporal, superior, inferior, and nasal meridians in 20 healthy subjects. Regions of interest (n = 1780) were extracted at regular intervals along each meridian. Cone mosaic geometry was assessed using a variety of metrics − density, density recovery profile distance (DRPD), nearest neighbor distance (NND), intercell distance (ICD), farthest neighbor distance (FND), percentage of …


Image-Based Quantification Of 3d Morphology For Bifurcations In The Left Coronary Artery: Application To Stent Design, Laura M. Ellwein, David S. Marks, Raymond Q. Migrino, Dennis Foley, Sara Sherman, John F. Ladisa Jr. Jun 2016

Image-Based Quantification Of 3d Morphology For Bifurcations In The Left Coronary Artery: Application To Stent Design, Laura M. Ellwein, David S. Marks, Raymond Q. Migrino, Dennis Foley, Sara Sherman, John F. Ladisa Jr.

Biomedical Engineering Faculty Research and Publications

Background

Improved strategies for stent‐based treatment of coronary artery disease at bifurcations require a greater understanding of artery morphology.

Objective

We developed a workflow to quantify morphology in the left main coronary (LMCA), left anterior descending (LAD), and left circumflex (LCX) artery bifurcations.

Methods

Computational models of each bifurcation were created for 55 patients using computed tomography images in 3D segmentation software. Metrics including cross‐sectional area, length, eccentricity, taper, curvature, planarity, branching law parameters, and bifurcation angles were assessed using open‐sources software and custom applications. Geometric characterization was performed by comparison of means, correlation, and linear discriminant analysis (LDA).

Results …


Mg2+ Differentially Regulates Two Modes Of Mitochondrial Ca2+ Uptake In Isolated Cardiac Mitochondria: Implications For Mitochondrial Ca2+ Sequestration, Christoph A. Blomeyer, Jason Bazil, David F. Stowe, Ranjan K. Dash, Amadou Ks Camara Jun 2016

Mg2+ Differentially Regulates Two Modes Of Mitochondrial Ca2+ Uptake In Isolated Cardiac Mitochondria: Implications For Mitochondrial Ca2+ Sequestration, Christoph A. Blomeyer, Jason Bazil, David F. Stowe, Ranjan K. Dash, Amadou Ks Camara

Biomedical Engineering Faculty Research and Publications

The manner in which mitochondria take up and store Ca2+ remains highly debated. Recent experimental and computational evidence has suggested the presence of at least two modes of Ca2+ uptake and a complex Ca2+ sequestration mechanism in mitochondria. But how Mg2+ regulates these different modes of Ca2+ uptake as well as mitochondrial Ca2+ sequestration is not known. In this study, we investigated two different ways by which mitochondria take up and sequester Ca2+ by using two different protocols. Isolated guinea pig cardiac mitochondria were exposed to varying concentrations of CaCl2 in the …


Longitudinal Imaging Of Microvascular Remodelling In Proliferative Diabetic Retinopathy Using Adaptive Optics Scanning Light Ophthalmoscopy, Toco Yuen Ping Chui, Alexander Pinhas, Alexander Gan, Moataz Razeen, Nishit Shah, Eric Cheang, Chun L. Liu, Alfredo Dubra, Richard B. Rosen May 2016

Longitudinal Imaging Of Microvascular Remodelling In Proliferative Diabetic Retinopathy Using Adaptive Optics Scanning Light Ophthalmoscopy, Toco Yuen Ping Chui, Alexander Pinhas, Alexander Gan, Moataz Razeen, Nishit Shah, Eric Cheang, Chun L. Liu, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

Purpose

To characterise longitudinal changes in the retinal microvasculature of type 2 diabetes mellitus (T2DM) as exemplified in a patient with proliferative diabetic retinopathy (PDR) using an adaptive optics scanning light ophthalmoscope (AOSLO).

Methods

A 35-year-old T2DM patient with PDR treated with scatter pan-retinal photocoagulation at the inferior retina 1 day prior to initial AOSLO imaging along with a 24-year-old healthy control were imaged in this study. AOSLO vascular structural and perfusion maps were acquired at four visits over a 20-week period. Capillary diameter and microaneurysm area changes were measured on the AOSLO structural maps. Imaging repeatability was established using …


Automatic Detection Of Cone Photoreceptors In Split Detector Adaptive Optics Scanning Light Ophthalmoscope Images, David Cunefare, Robert F. Cooper, Brian P. Higgins, David F. Katz, Alfredo Dubra, Joseph Carroll, Sina Farsiu May 2016

Automatic Detection Of Cone Photoreceptors In Split Detector Adaptive Optics Scanning Light Ophthalmoscope Images, David Cunefare, Robert F. Cooper, Brian P. Higgins, David F. Katz, Alfredo Dubra, Joseph Carroll, Sina Farsiu

Biomedical Engineering Faculty Research and Publications

Quantitative analysis of the cone photoreceptor mosaic in the living retina is potentially useful for early diagnosis and prognosis of many ocular diseases. Non-confocal split detector based adaptive optics scanning light ophthalmoscope (AOSLO) imaging reveals the cone photoreceptor inner segment mosaics often not visualized on confocal AOSLO imaging. Despite recent advances in automated cone segmentation algorithms for confocal AOSLO imagery, quantitative analysis of split detector AOSLO images is currently a time-consuming manual process. In this paper, we present the fully automatic adaptive filtering and local detection (AFLD) method for detecting cones in split detector AOSLO images. We validated our algorithm …


An Algorithm For Constrained One-Step Inversion Of Spectral Ct Data, Rina Foygel Barber, Emil Y. Sidky, Taly Gilat Schmidt, Xiaochuan Pan Apr 2016

An Algorithm For Constrained One-Step Inversion Of Spectral Ct Data, Rina Foygel Barber, Emil Y. Sidky, Taly Gilat Schmidt, Xiaochuan Pan

Biomedical Engineering Faculty Research and Publications

We develop a primal-dual algorithm that allows for one-step inversion of spectral CT transmission photon counts data to a basis map decomposition. The algorithm allows for image constraints to be enforced on the basis maps during the inversion. The derivation of the algorithm makes use of a local upper bounding quadratic approximation to generate descent steps for non-convex spectral CT data discrepancy terms, combined with a new convex-concave optimization algorithm. Convergence of the algorithm is demonstrated on simulated spectral CT data. Simulations with noise and anthropomorphic phantoms show examples of how to employ the constrained one-step algorithm for spectral CT …


Optimal Schedules In Multitask Motor Learning, Jeong Yoon Lee, Youngmin Oh, Sung Shin Kim, Robert A. Scheidt, Nicolas Schweighofer Apr 2016

Optimal Schedules In Multitask Motor Learning, Jeong Yoon Lee, Youngmin Oh, Sung Shin Kim, Robert A. Scheidt, Nicolas Schweighofer

Biomedical Engineering Faculty Research and Publications

Although scheduling multiple tasks in motor learning to maximize long-term retention of performance is of great practical importance in sports training and motor rehabilitation after brain injury, it is unclear how to do so. We propose here a novel theoretical approach that uses optimal control theory and computational models of motor adaptation to determine schedules that maximize long-term retention predictively. Using Pontryagin’s maximum principle, we derived a control law that determines the trial-by-trial task choice that maximizes overall delayed retention for all tasks, as predicted by the state-space model. Simulations of a single session of adaptation with two tasks show …


Alterations In Cortical Sensorimotor Connectivity Following Complete Cervical Spinal Cord Injury: A Prospective Resting-State Fmri Study, Akinwunmi Oni-Orisan, Mayank Kaushal, Wenjun Li, Jack Leschke, B. Douglas Ward, Aditya Vedantam, Benjamin Kalinosky, Matthew D. Budde, Brian D. Schmit, Shi-Jiang Li, Viashnavi Muqeet, Shekar N. Kurpad Mar 2016

Alterations In Cortical Sensorimotor Connectivity Following Complete Cervical Spinal Cord Injury: A Prospective Resting-State Fmri Study, Akinwunmi Oni-Orisan, Mayank Kaushal, Wenjun Li, Jack Leschke, B. Douglas Ward, Aditya Vedantam, Benjamin Kalinosky, Matthew D. Budde, Brian D. Schmit, Shi-Jiang Li, Viashnavi Muqeet, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

Functional magnetic resonance imaging (fMRI) studies have demonstrated alterations during task-induced brain activation in spinal cord injury (SCI) patients. The interruption to structural integrity of the spinal cord and the resultant disrupted flow of bidirectional communication between the brain and the spinal cord might contribute to the observed dynamic reorganization (neural plasticity). However, the effect of SCI on brain resting-state connectivity patterns remains unclear. We undertook a prospective resting-state fMRI (rs-fMRI) study to explore changes to cortical activation patterns following SCI. With institutional review board approval, rs-fMRI data was obtained in eleven patients with complete cervical SCI (>2 years …


Faculty Intellectual Property In Capstone Design Projects, Jay R. Goldberg Mar 2016

Faculty Intellectual Property In Capstone Design Projects, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Reports on the Capstone Design challenge, focusing on design challenges for the participants. By focusing on the design process and allowing students to gain hands-on experience in design, they help prepare students for careers in engineering. In many capstone design courses, students design a product or device to solve a problem and build and test a prototype to verify and validate the design. Student teams are often advised by some combination of industry sponsors, clinical advisors, and/or faculty advisors. Faculty advisors serve as technical advisors to the teams and provide guidance to keep them on track. They are not members …


Instrumented Lumbar Corpectomy And Spinal Reconstruction Comparing Rhbmp-2/Compression-Resistant Matrix, Rhbmp-2/Absorbable Collagen Sponge/Ceramic Granules Mixture, And Autograft In Two Different Devices: A Study In Sheep, Jeffrey M. Toth, David G. Schwartz, Jean-Piere Mobasser, Joseph Williams Mar 2016

Instrumented Lumbar Corpectomy And Spinal Reconstruction Comparing Rhbmp-2/Compression-Resistant Matrix, Rhbmp-2/Absorbable Collagen Sponge/Ceramic Granules Mixture, And Autograft In Two Different Devices: A Study In Sheep, Jeffrey M. Toth, David G. Schwartz, Jean-Piere Mobasser, Joseph Williams

Biomedical Engineering Faculty Research and Publications

Study Design. Fusion success with rhBMP-2 and autograft in titanium or PEEK corpectomy devices was evaluated in a sheep lumbar corpectomy model. The 6 treatment groups included titanium mesh or PEEK corpectomy devices filled with rhBMP-2 on a compression-resistant matrix (CRM) carrier; rhBMP-2 in a morselized absorbable collagen sponge (ACS) carrier combined with resorbable ceramic granules; and autograft.

Objective. The aim of this study was to determine fusion rates associated with 2 different preparations of rhBMP-2 as well as autograft in an instrumented ovine lumbar corpectomy model 6 months postoperatively.

Summary of Background Data. Vertebral reconstruction with corpectomy devices requires …


Effects Of Intraframe Distortion On Measures Of Cone Mosaic Geometry From Adaptive Optics Scanning Light Ophthalmoscopy, Robert F. Cooper, Yusufu N. Sulai, Adam M. Dubis, Toco Y.P. Chui, Richard B. Rosen, Michel Michaelides, Alfredo Dubra, Joseph Carroll Feb 2016

Effects Of Intraframe Distortion On Measures Of Cone Mosaic Geometry From Adaptive Optics Scanning Light Ophthalmoscopy, Robert F. Cooper, Yusufu N. Sulai, Adam M. Dubis, Toco Y.P. Chui, Richard B. Rosen, Michel Michaelides, Alfredo Dubra, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose: To characterize the effects of intraframe distortion due to involuntary eye motion on measures of cone mosaic geometry derived from adaptive optics scanning light ophthalmoscope (AOSLO) images.

Methods: We acquired AOSLO image sequences from 20 subjects at 1.0, 2.0, and 5.08 temporal from fixation. An expert grader manually selected 10 minimally distorted reference frames from each 150-frame sequence for subsequent registration. Cone mosaic geometry was measured in all registered images (n ¼ 600) using multiple metrics, and the repeatability of these metrics was used to assess the impact of the distortions from each reference frame. In nine additional subjects, …


Assessing Photoreceptor Structure Associated With Ellipsoid Zone Disruptions Visualized With Optical Coherence Tomography, Drew Scoles, John A. Flatter, Robert F. Cooper, Christopher S. Langlo, Scott Robison, Maureen Neitz, David V. Weinberg, Mark E. Pennesi, Dennis P. Han, Alfredo Dubra, Joseph Carroll Jan 2016

Assessing Photoreceptor Structure Associated With Ellipsoid Zone Disruptions Visualized With Optical Coherence Tomography, Drew Scoles, John A. Flatter, Robert F. Cooper, Christopher S. Langlo, Scott Robison, Maureen Neitz, David V. Weinberg, Mark E. Pennesi, Dennis P. Han, Alfredo Dubra, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose: To compare images of photoreceptor layer disruptions obtained with optical coherence tomography (OCT) and adaptive optics scanning light ophthalmoscopy (AOSLO) in a variety of pathologic states.

Methods: Five subjects with photoreceptor ellipsoid zone disruption as per OCT and clinical diagnoses of closed-globe blunt ocular trauma (n = 2), macular telangiectasia type 2 (n = 1), blue-cone monochromacy (n = 1), or cone-rod dystrophy (n = 1) were included. Images were acquired within and around photoreceptor lesions using spectral domain OCT, confocal AOSLO, and split-detector AOSLO.

Results: There were substantial differences in the extent and appearance of the photoreceptor mosaic …


Finite Element Modeling And Analysis Applications In Osteogenesis Imperfecta, Jessica M. Fritz, Nicole M. Grosland, Peter Smith, Gerald F. Harris Jan 2016

Finite Element Modeling And Analysis Applications In Osteogenesis Imperfecta, Jessica M. Fritz, Nicole M. Grosland, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Understanding the biomechanics of bones in persons with osteogenesis imperfecta (OI) is a key component to further understanding the disease, optimizing treatment and quality of life, as well as injury prevention. However, it is not feasible to study bone biomechanics in vivo. Thus, modeling may play a key role in understanding how OI bones respond to the loading experienced during various activities, especially ambulation. Biomechanical modeling can provide insight into bone fracture risks, such as type and location, from single applied loads or repetitive loading. One method for obtaining this information is via a finite element analysis (FEA). FEA is …


Biomechanics Of Osteogenesis Imperfecta: Current Concepts And Emerging Horizons, Carolyne Albert, Jessica M. Fritz, Gerald F. Harris Jan 2016

Biomechanics Of Osteogenesis Imperfecta: Current Concepts And Emerging Horizons, Carolyne Albert, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Osteogenesis inperfecta (OI) is associated with bone fragility. Long bone fractures are a common occurrence in individuals with OI. Although there have been significant advances in understanding the genetic defects associated with OI, the mechanisms behind bone fragility in this patient population are not yet well understood. This fragility is believed to stem in part from characteristic bone mass deficiencies. Research further suggests that the material properties of the bone are also compromised in individuals with this disorder. There is currently on quantitative method available to assess bone fracture risk in individuals with OI. This chapter examines several critical elements …


Nih Visible Human Project Humerus Numerical And Physical Models: Characterization For Osteogenesis Imperfecta Fracture Study, Prateek Grover, Gerald F. Harris Jan 2016

Nih Visible Human Project Humerus Numerical And Physical Models: Characterization For Osteogenesis Imperfecta Fracture Study, Prateek Grover, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.