Biomedical Engineering and Bioengineering Commons^™

Role Of Micro-Ct In The Visualization, Measurement, And Quantification Of Bone Structure In Osteogenesis Imperfecta, Robert C. Molthen, John Jameson, Carolyne Albert, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Lessons Learned From A 10-Year Collaboration Between Engineering And Industrial Design Students In Capstone Design Projects, Jay R. Goldberg, Pascal Malassigné

Biomedical Engineering Faculty Research and Publications

Engineers and industrial designers have different approaches to problem solving. Both place heavy emphasis on identification of customer needs, manufacturing methods, and prototyping. Industrial designers focus on aesthetics, ergonomics, ease of use, and the user’s experience. They tend to be more visual and more concerned with the interaction between users and products. Engineers focus on functionality, performance requirements, analytical modeling, and design verification and validation. They tend to be more analytical and more concerned with the design of internal components and product performance. Engineers and industrial designers often work together on project teams in industry. Collaboration between the two groups …

Comparing Offline Decoding Performance In Physiologically Defined Neuronal Classes, Matthew D. Best, Kazutaka Takahashi, Aaron J. Suminski, Christian Ethier, Lee E. Miller, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

Objective: Recently, several studies have documented the presence of a bimodal distribution of spike waveform widths in primary motor cortex. Although narrow and wide spiking neurons, corresponding to the two modes of the distribution, exhibit different response properties, it remains unknown if these differences give rise to differential decoding performance between these two classes of cells. Approach: We used a Gaussian mixture model to classify neurons into narrow and wide physiological classes. Using similar-size, random samples of neurons from these two physiological classes, we trained offline decoding models to predict a variety of movement features. We compared offline …

Upper Extremity Inverse Dynamics Model For Loftstrand Crutch-Assisted Gait In Children With Osteogenesis Imperfecta, Brooke A. Slavens, Neha Bhagchandani, Mei Wang, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Fluoroscopic System For Assessment Of In Vivo Hindfoot Kinematics During Gait: Control Data And Applications In Osteogenesis Imperfecta, Ben Mchenry, Jason Long, Peter Smith, Haluk Altiok, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Severity Of Spinal Cord Injury Influences Diffusion Tensor Imaging Of The Brain, Michael B. Jirjis, Aditya Vedantam, Matthew D. Budde, Benjamin Kalinosky, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

Background: The purpose of this study was to determine whether DTI changes in the brain induced by a thoracic spinal cord injury are sensitive to varying severity of spinal contusion in rats.

Methods: A control, mild, moderate, or severe contusion injury was administered over the eighth thoracic vertebral level in 32 Sprague-Dawley rats. At 11 weeks postinjury, ex vivo DTI of the brain was performed on a 9.4T Bruker scanner using a pulsed gradient spin-echo sequence.

Results: Mean water diffusion in the internal capsule regions of the brain and pyramid locations of the brainstem were correlated with motor function (r …

Automated Selection Of The Optimal Cardiac Phase For Single-Beat Coronary Ct Angiography Reconstruction, Daniel Stassi, S. Dutta, H. Ma, A. Soderman, D. Pazzani, E. Gros, D. Okerlund, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose: Reconstructing a low-motion cardiac phase is expected to improve coronary artery visualization in coronary computed tomography angiography (CCTA) exams. This study developed an automated algorithm for selecting the optimal cardiac phase for CCTA reconstruction. The algorithm uses prospectively gated, single-beat, multiphase data made possible by wide cone-beam imaging. The proposed algorithm differs from previous approaches because the optimal phase is identified based on vessel image quality (IQ) directly, compared to previous approaches that included motion estimation and interphase processing. Because there is no processing of interphase information, the algorithm can be applied to any sampling of image phases, …

Material And Structural Aspects Of Bone In Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Bone fragility is a fundamental problem in individuals with osteogenesis imperfecta (OI). The mechanisms behind this fragility, however, are not yet well understood. Multiple factors appear to contribute to the increased fracture risk in OI. At the structural level, bone mass deficiency can result in increased stress levels within bones. The underlying mineral and collagen abnormalities that define OI are also believed to result in compromised material-level properties. The variability of collagen biochemical irregularities causing OI and the corresponding heterogeneity of disease severity result in abnormalities that are not easily generalized within the OI population.

The aims of this chapter …

Motion Analysis Strategy Appropriate For 3d Kinematic Assessment Of Children And Adults With Osteogenesis Imperfecta, Jeffrey D. Kertis, Jessica M. Fritz, Sergey Tarima, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Human motion analysis provides a quantitative means of assessing whole body and segmental motion of subjects with musculoskeletal pathologies. This chapter describes a low cost motion analysis appropriate for complete three-dimensional (3D) assessment of upper and lower extremity kinematics. The system has been designed to support lower cost outreach efforts that require accuracy and resolution on the order of classical fixed lot systems such as Vicon. The focus of this work addresses the assessment needs typically seen in adults and children with osteogenesis imperfect (OI) experiencing ambulatory and upper extremity challenges.

Quantitative Assessment Of Children With Osteogenesis Imperfecta, Adam Graf, Joseph Krzak, Angela Caudill, Ann Flanagan, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Assessments of children with Osteogenesis Imperfecta (OI) are typically limited to a physical exam and observations from a clinician during a hospital visit. Often quantitative information such as bone mineral density and outcome questionnaires is obtained, but with the increasing prevalence of motion analysis and other performance type laboratories, there are many other tools available, which could be beneficial to this patient population. These laboratories can provide date supplementary to morphologic and radiographic data that is helpful in tracking changes in the patient’s functional abilities, recover from fracture, and treatment outcomes. This chapter will cover some useful evaluation methods for …

Walker Design For Kinetic Assessment Of Upper Extremity Joint Demands In Children With Osteogenesis Imperfecta, Katherine A. Konop, Kelly M.B. Strifling, Mei Wang, Jeffrey P. Schwab, Jeffrey D. Ackman, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Assessing The Spatial Relationship Between Fixation And Foveal Specializations, Melissa A. Wilk, Adam M. Dubis, Robert F. Cooper, Phyllis Summerfelt, Alfredo Dubra, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Increased cone photoreceptor density, an avascular zone (FAZ), and the displacement of inner retinal neurons to form a pit are distinct features of the human fovea. As the fovea provides the majority of our vision, appreciating how these anatomical specializations are related is important for understanding foveal development, normal visual function, and retinal disease. Here we evaluated the relationship between these specializations and their location relative to the preferred retinal locus of fixation (PRL). We measured foveal pit volume, FAZ area, peak cone density, and location of the PRL in 22 subjects with normal vision using optical coherence tomography and …

Motor Output Variability Impairs Driving Ability In Older Adults, Neha Lodha, Hwasil Moon, Changki Kim, Tanya Onushko, Evangelos A. Christou

Biomedical Engineering Faculty Research and Publications

Background: The functional declines with aging relate to deficits in motor control and strength. In this study, we determine whether older adults exhibit impaired driving as a consequence of declines in motor control or strength.

Methods: Young and older adults performed the following tasks: (i) maximum voluntary contractions of ankle dorsiflexion and plantarflexion; (ii) sinusoidal tracking with isolated ankle dorsiflexion; and (iii) a reactive driving task that required responding to unexpected brake lights of the car ahead. We quantified motor control with ankle force variability, gas position variability, and brake force variability. We quantified reactive driving performance with a combination …

Smartphone Microendoscopy For High Resolution Fluorescence Imaging, Xiangqian Hong, Vivek K. Nagarajan, Dale H. Mugler, Bing Yu

Biomedical Engineering Faculty Research and Publications

High resolution optical endoscopes arc increasingly used in diagnosis of various medical conditions of internal organs, such as the cervix and gastrointestinal (GI) tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this paper, we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 μm. Images collected from ex vivo, in vitro and in vivo samples using the device …

Effect Of Tendon Vibration On Hemiparetic Arm Stability In Unstable Workspaces, Megan O. Conrad, Bani Gadhoke, Robert A. Scheidt, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Sensory stimulation of wrist musculature can enhance stability in the proximal arm and may be a useful therapy aimed at improving arm control post-stroke. Specifically, our prior research indicates tendon vibration can enhance stability during point-to-point arm movements and in tracking tasks. The goal of the present study was to investigate the influence of forearm tendon vibration on endpoint stability, measured at the hand, immediately following forward arm movements in an unstable environment. Both proximal and distal workspaces were tested. Ten hemiparetic stroke subjects and 5 healthy controls made forward arm movements while grasping the handle of a two-joint robotic …

Increased Lower Limb Spasticity But Not Strength Or Function Following A Single-Dose Serotonin Reuptake Inhibitor In Chronic Stroke, Krishnaj Gourab, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

Objective: To investigate the effects of single doses of a selective serotonin reuptake inhibitor (SSRI) on lower limb voluntary and reflex function in individuals with chronic stroke.

Design: Double-blind, randomized, placebo-controlled crossover trial.

Setting: Outpatient research setting.

Participants: Individuals (N=10; 7 men; mean age ± SD, 57±10y) with poststroke hemiplegia of >1 year duration who completed all assessments.

Interventions: Patients were assessed before and 5 hours after single-dose, overencapsulated 10-mg doses of escitalopram (SSRI) or placebo, with 1 week between conditions.

Main Outcome Measures: Primary assessments included maximal ankle and knee isometric strength, and velocity-dependent (30°/s–120°/s) plantarflexor stretch reflexes under …

Retinal Architecture In ​Rgs9- And ​R9ap-Associated Retinal Dysfunction (Bradyopsia), Rupert W. Strauss, Adam M. Dubis, Robert F. Cooper, Rola Ba-Abbad, Anthony T. Moore, Andrew R. Webster, Alfredo Dubra, Joseph Carroll, Michel Michaelides

Biomedical Engineering Faculty Research and Publications

Purpose

To characterize photoreceptor structure and mosaic integrity in subjects with RGS9- and R9AP-associated retinal dysfunction (bradyopsia) and compare to previous observations in other cone dysfunction disorders such as oligocone trichromacy.

Design

Observational case series.

Methods

setting: Moorfields Eye Hospital (United Kingdom) and Medical College Wisconsin (USA). study population: Six eyes of 3 subjects with disease-causing variants in RGS9 or R9AP. main outcome measures: Detailed retinal imaging using spectral-domain optical coherence tomography and confocal adaptive-optics scanning light ophthalmoscopy.

Results

Cone density at 100 μm from foveal center ranged from 123 132 cones/mm²to 140 013 cones/mm^{2 …}

Detection Of Acute Nervous System Injury With Advanced Diffusion-Weighted Mri: A Simulation And Sensitivity Analysis, Nathan P. Skinner, Shekar N. Kurpad, Brian D. Schmit, Matthew D. Budde

Biomedical Engineering Faculty Research and Publications

Diffusion-weighted imaging (DWI) is a powerful tool to investigate the microscopic structure of the central nervous system (CNS). Diffusion tensor imaging (DTI), a common model of the DWI signal, has a demonstrated sensitivity to detect microscopic changes as a result of injury or disease. However, DTI and other similar models have inherent limitations that reduce their specificity for certain pathological features, particularly in tissues with complex fiber arrangements. Methods such as double pulsed field gradient (dPFG) and q-vector magic angle spinning (qMAS) have been proposed to specifically probe the underlying microscopic anisotropy without interference from the macroscopic tissue organization. …

Computational Replication Of The Patient-Specific Stenting Procedure For Coronary Artery Bifurcations: From Oct And Ct Imaging To Structural And Hemodynamics Analyses, Claudio Chiastra, Wei Wu, Benjamin Dickerhoff, Ali Aleiou, Gabriele Dubini, Hiromasa Otake, Francesco Migliavacca, John F. Ladisa Jr.

Biomedical Engineering Faculty Research and Publications

The optimal stenting technique for coronary artery bifurcations is still debated. With additional advances computational simulations can soon be used to compare stent designs or strategies based on verified structural and hemodynamics results in order to identify the optimal solution for each individual’s anatomy. In this study, patient-specific simulations of stent deployment were performed for 2 cases to replicate the complete procedure conducted by interventional cardiologists. Subsequent computational fluid dynamics (CFD) analyses were conducted to quantify hemodynamic quantities linked to restenosis.

Patient-specific pre-operative models of coronary bifurcations were reconstructed from CT angiography and optical coherence tomography (OCT). Plaque location and …

Effect Of Imperceptible Vibratory Noise Applied To Wrist Skin On Fingertip Touch Evoked Potentials – An Eeg Study, Na Jin Seo, Kishor Lakshminarayanan, Leonardo Bonilha, Abigail W. Lauer, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Random vibration applied to skin can change the sense of touch. Specifically, low amplitude white-noise vibration can improve fingertip touch perception. In fact, fingertip touch sensation can improve even when imperceptible random vibration is applied to other remote upper extremity areas such as wrist, dorsum of the hand, or forearm. As such, vibration can be used to manipulate sensory feedback and improve dexterity, particularly during neurological rehabilitation. Nonetheless, the neurological bases for remote vibration enhanced sensory feedback are yet poorly understood. This study examined how imperceptible random vibration applied to the wrist changes cortical activity for fingertip sensation. We measured …

Alagebrium Inhibits Neointimal Hyperplasia And Restores Distributions Of Wall Shear Stress By Reducing Downstream Vascular Resistance In Obese And Diabetic Rats, Hongfeng Wang, Dorothee Weihrauch, Judy R. Kersten, Jeffrey M. Toth, Anthony G. Passerini, Anita Rajamani, Sonja Schrepfer, John F. Ladisa Jr.

Biomedical Engineering Faculty Research and Publications

Mechanisms of restenosis in type 2 diabetes mellitus (T2DM) are incompletely elucidated, but advanced glycation end-products (AGEs)-induced vascular remodeling likely contributes. We tested the hypothesis that AGEs-related collagen cross-linking (ARCC) leads to increased downstream vascular resistance (DVR), and altered in-stent hemodynamics, thereby promoting neointimal hyperplasia (NH) in T2DM. We proposed that decreasing ARCC with ALT-711 (Alagebrium) would mitigate this response. Abdominal aortic stents were implanted in Zucker lean (ZL), obese (ZO), and diabetic (ZD) rats. Blood flow, vessel diameter, and wall shear stress (WSS) were calculated after 21 days, and NH was quantified. Arterial segments (aorta, carotid, iliac, femoral, arterioles) …

Fellow Eye Changes In Patients With Nonischemic Central Retinal Vein Occlusion: Assessment Of Perfused Foveal Microvascular Density And Identification Of Nonperfused Capillaries, Alexander Pinhas, Michael Dubow, Nishit Shah, Eric Cheang, Chun L. Liu, Moataz Razeen, Alexander Gan, Rishard Weitz, Yusufu N. Sulai, Toco Y.P. Chui, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

Purpose: Eyes fellow to nonischemic central retinal vein occlusion (CRVO) were examined for abnormalities, which might explain their increased risk for future occlusion, using adaptive optics scanning light ophthalmoscope fluorescein angiography.

Methods: Adaptive optics scanning light ophthalmoscope fluorescein angiography foveal microvascular densities were calculated. Nonperfused capillaries adjacent to the foveal avascular zone were identified. Spectral domain optical coherence tomography, ultrawide field fluorescein angiographies, and microperimetry were also performed.

Results: Ten fellow eyes of nine nonischemic CRVO and 1 nonischemic hemi-CRVO subjects and four affected eyes of three nonischemic CRVO and one nonischemic hemi-CRVO subjects were imaged. Ninety percent of fellow …

Quantifying Cross-Scatter Contamination In Biplane Fluoroscopy Motion Analysis Systems, Janelle A. Cross, Ben Mchenry, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Biplane fluoroscopy is used for dynamic in vivo three-dimensional motion analysis of various joints of the body. Cross-scatter between the two fluoroscopy systems may limit tracking accuracy. This study measured the magnitude and effects of cross-scatter in biplane fluoroscopic images. Four cylindrical phantoms of 4-, 6-, 8-, and 10-in. diameter were imaged at varying kVp levels to determine the cross-scatter fraction and contrast-to-noise ratio (CNR). Monte Carlo simulations quantified the effect of the gantry angle on the cross-scatter fraction. A cadaver foot with implanted beads was also imaged. The effect of cross-scatter on marker-based tracking accuracy was investigated. Results demonstrated …

Biomechanics Of Pediatric Manual Wheelchair Mobility, Brooke A. Slavens, Alyssa J. Schnorenberg, Christine M. Aurit, Sergey Tarima, Lawrence C. Vogel, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments …

Opportunities To Identify Unmet Needs Outside Of The Operating Room, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

The ability to identify unmet needs and new product opportunities is an important skill for biomedical engineering students planning a career in the medical device industry. Most biomedical engineering graduates will work in industry where many projects will not be defined for them. They will need to work with physicians, surgeons, nurses, clinical engineers, and other users of medical technology to identify problems and unmet needs and will work closely with marketing, sales, and other personnel to identify new product development opportunities. Students will be better prepared for careers involving the development of new medical devices if they are able …

Stretch‐Induced Increase In Cardiac Contractility Is Independent Of Myocyte Ca2+ While Block Of Stretch Channels By Streptomycin Improves Contractility After Ischemic Stunning, Samhita S. Rhodes, Amadou Ks Camara, Mohammed Aldakkak, James S. Heisner, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Stretching the cardiac left ventricle (LV) enhances contractility but its effect on myoplasmic [Ca²⁺] is controversial. We measured LV pressure (LVP) and [Ca²⁺] as a function of intra-LV stretch in guinea pig intact hearts before and after 15 min global stunning ± perfusion with streptomycin (STM), a stretch activated channel blocker. LV wall [Ca²⁺] was measured by indo-1 fluorescence and LVP by a saline-filled latex balloon inflated in 50 μL steps to stretch the LV. We implemented a mathematical model to interpret crossbridge dynamics and myofilament Ca²⁺ responsiveness from the instantaneous relationship between …

Validation Of A Finite Element Model Of The Humerus For Fracture Risk Assessment During Assisted Ambulation, Jessica M. Fritz, Prateek Grover, Nicole M. Grosland, Carolyne Albert, Linda M. Mcgrady, Mei Wang, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Using Swing Resistance And Assistance To Improve Gait Symmetry In Individuals Post-Stroke, Sheng-Che Yen, Brian D. Schmit, Ming Wu

Biomedical Engineering Faculty Research and Publications

A major characteristic of hemiplegic gait observed in individuals post-stroke is spatial and temporal asymmetry, which may increase energy expenditure and the risk of falls. The purpose of this study was to examine the effects of swing resistance/assistance applied to the affected leg on gait symmetry in individuals post-stroke. We recruited 10 subjects with chronic stroke who demonstrated a shorter step length with their affected leg in comparison to the non-affected leg during walking. They participated in two test sessions for swing resistance and swing assistance, respectively. During the adaptation period, subjects counteracted the step length deviation caused by the …

Finite Element Assessment Of Pediatric Femoral Response To Loading During Ambulation: Normal Vs. Osteogenesis Imperfecta (Oi) Bone, Jessica M. Fritz, Carolyne Albert, Nicole M. Grosland, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Gene Expression In Experimental Aortic Coarctation And Repair: Candidate Genes For Therapeutic Intervention?, John F. Ladisa Jr., Serdar Bozdag, Jessica Olson, Ramani Ramchandran, Judy R. Kersten, Thomas J. Eddinger

Biomedical Engineering Faculty Research and Publications

Coarctation of the aorta (CoA) is a constriction of the proximal descending thoracic aorta and is one of the most common congenital cardiovascular defects. Treatments for CoA improve life expectancy, but morbidity persists, particularly due to the development of chronic hypertension (HTN). Identifying the mechanisms of morbidity is difficult in humans due to confounding variables such as age at repair, follow-up duration, coarctation severity and concurrent anomalies. We previously developed an experimental model that replicates aortic pathology in humans with CoA without these confounding variables, and mimics correction at various times using dissolvable suture. Here we present the most comprehensive …