Medical Biophysics Commons^™

Comparison Of Quality Control Methods For Automated Diffusion Tensor Imaging Analysis Pipelines, Seyyed M.H. Haddad, Christopher J.M. Scott, Miracle Ozzoude, Melissa F. Holmes, Stephen R. Arnott, Nuwan D. Nanayakkara, Joel Ramirez, Sandra E. Black, Dar Dowlatshahi, Stephen C. Strother, Richard H. Swartz, Sean Symons, Manuel Montero-Odasso, Robert Bartha

Medical Biophysics Publications

© 2019 Haddad et al. The processing of brain diffusion tensor imaging (DTI) data for large cohort studies requires fully automatic pipelines to perform quality control (QC) and artifact/outlier removal procedures on the raw DTI data prior to calculation of diffusion parameters. In this study, three automatic DTI processing pipelines, each complying with the general ENIGMA framework, were designed by uniquely combining multiple image processing software tools. Different QC procedures based on the RESTORE algorithm, the DTIPrep protocol, and a combination of both methods were compared using simulated ground truth and artifact containing DTI datasets modeling eddy current induced distortions, …

Mousebytes, An Open-Access High-Throughput Pipeline And Database For Rodent Touchscreen-Based Cognitive Assessment, Flavio H. Beraldo, Daniel Palmer, Sara Memar, David I. Wasserman, Wai Jane V. Lee, Shuai Liang, Samantha D. Creighton, Benjamin Kolisnyk, Matthew F. Cowan, Justin Mels, Talal S. Masood, Chris Fodor, Mohammed A. Al-Onaizi, Robert Bartha, Tom Gee, Lisa M. Saksida, Timothy J. Bussey, Stephen S. Strother, Vania F. Prado, Boyer D. Winters, Marco A.M. Prado

Medical Biophysics Publications

© 2019, eLife Sciences Publications Ltd. All rights reserved. Open Science has changed research by making data accessible and shareable, contributing to replicability to accelerate and disseminate knowledge. However, for rodent cognitive studies the availability of tools to share and disseminate data is scarce. Automated touchscreen-based tests enable systematic cognitive assessment with easily standardised outputs that can facilitate data dissemination. Here we present an integration of touchscreen cognitive testing with an open-access database public repository (mousebytes.ca), as well as a Web platform for knowledge dissemination (https://touchscreencognition.org). We complement these resources with the largest dataset of age-dependent high-level cognitive assessment of …

Genome-Wide Association Analysis Of Hippocampal Volume Identifies Enrichment Of Neurogenesis-Related Pathways, Emrin Horgusluoglu-Moloch, Shannon L. Risacher, Paul K. Crane, Derrek Hibar, Paul M. Thompson, Andrew J. Saykin, Kwangsik Nho, Michael W. Weiner, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, John Q. Trojanowki, Arthur W. Toga, Laurel Beckett, Robert C. Green, John Morris, Leslie M. Shaw, Jeffrey Kaye, Joseph Quinn, Lisa Silbert, Betty Lind, Raina Carter, Sara Dolen, Lon S. Schneider, Sonia Pawluczyk, Mauricio Beccera, Liberty Teodoro, Bryan M. Spann, James Brewer, Helen Vanderswag, Adam Fleisher

Medical Biophysics Publications

© 2019, The Author(s). Adult neurogenesis occurs in the dentate gyrus of the hippocampus during adulthood and contributes to sustaining the hippocampal formation. To investigate whether neurogenesis-related pathways are associated with hippocampal volume, we performed gene-set enrichment analysis using summary statistics from a large-scale genome-wide association study (N = 13,163) of hippocampal volume from the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) Consortium and two year hippocampal volume changes from baseline in cognitively normal individuals from Alzheimer’s Disease Neuroimaging Initiative Cohort (ADNI). Gene-set enrichment analysis of hippocampal volume identified 44 significantly enriched biological pathways (FDR corrected p-value < 0.05), of which 38 pathways were related to neurogenesis-related processes including neurogenesis, generation of new neurons, neuronal development, and neuronal migration and differentiation. For genes highly represented in the significantly enriched neurogenesis-related pathways, gene-based association analysis identified TESC, ACVR1, MSRB3, and DPP4 as significantly associated with hippocampal volume. Furthermore, co-expression network-based functional analysis of gene expression data in the hippocampal subfields, CA1 and CA3, from 32 normal controls showed that distinct co-expression modules were mostly enriched in neurogenesis related pathways. Our results suggest that neurogenesis-related pathways may be enriched for hippocampal volume and that hippocampal volume may serve as a potential phenotype for the investigation of human adult neurogenesis.

The Bin1 Rs744373 Snp Is Associated With Increased Tau-Pet Levels And Impaired Memory, Nicolai Franzmeier, Anna Rubinski, Julia Neitzel, Michael Ewers, Michael W. Weiner, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, John Q. Trojanowski, Arthur W. Toga, Laurel Beckett, Robert C. Green, Andrew J. Saykin, John Morris, Leslie M. Shaw, Zaven Khachaturian, Greg Sorensen, Lew Kuller, Marcus Raichle, Steven Paul, Peter Davies, Howard Fillit, Franz Hefti, David Holtzman, Marek M. Mesulam, William Potter, Peter Snyder, Adam Schwartz, Tom Montine, Ronald G. Thomas, Michael Donohue

Medical Biophysics Publications

© 2019, The Author(s). The single nucleotide polymorphism (SNP) rs744373 in the bridging integrator-1 gene (BIN1) is a risk factor for Alzheimer’s disease (AD). In the brain, BIN1 is involved in endocytosis and sustaining cytoskeleton integrity. Post-mortem and in vitro studies suggest that BIN1-associated AD risk is mediated by increased tau pathology but whether rs744373 is associated with increased tau pathology in vivo is unknown. Here we find in 89 older individuals without dementia, that BIN1 rs744373 risk-allele carriers show higher AV1451 tau-PET across brain regions corresponding to Braak stages II–VI. In contrast, the BIN1 rs744373 SNP was not associated …

Multimodal Hippocampal Subfield Grading For Alzheimer’S Disease Classification, Kilian Hett, Vinh Thong Ta, Gwenaëlle Catheline, Thomas Tourdias, José V. Manjón, Pierrick Coupé, Michael W. Weiner, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, John Q. Trojanowki, Arthur W. Toga, Laurel Beckett, Robert C. Green, Andrew J. Saykin, John Morris, Leslie M. Shaw, Zaven Khachaturian, Greg Sorensen, Maria Carrillo, Lew Kuller, Marc Raichle, Steven Paul, Peter Davies, Howard Fillit, Franz Hefti, Davie Holtzman, M. Marcel Mesulam, William Potter, Peter Snyder, Tom Montine

Medical Biophysics Publications

© 2019, The Author(s). Numerous studies have proposed biomarkers based on magnetic resonance imaging (MRI) to detect and predict the risk of evolution toward Alzheimer’s disease (AD). Most of these methods have focused on the hippocampus, which is known to be one of the earliest structures impacted by the disease. To date, patch-based grading approaches provide among the best biomarkers based on the hippocampus. However, this structure is complex and is divided into different subfields, not equally impacted by AD. Former in-vivo imaging studies mainly investigated structural alterations of these subfields using volumetric measurements and microstructural modifications with mean diffusivity …

3d Vessel-Wall Virtual Histology Of Whole-Body Perfused Mice Using A Novel Heavy Element Stain, P. Joy Dunmore-Buyze, Charmainne Cruje, Zengxuan Nong, Jason J. Lee, John A. Kiernan, J. Geoffrey Pickering, Maria Drangova

Medical Biophysics Publications

Virtual histology – utilizing high-resolution three-dimensional imaging – is becoming readily available. Micro-computed tomography (micro-CT) is widely available and is often coupled with x-ray attenuating histological stains that mark specific tissue components for 3D virtual histology. In this study we describe a new tri-element x-ray attenuating stain and perfusion protocol that provides micro-CT contrast of the entire vasculature of an intact mouse. The stain – derived from an established histology stain (Verhoeff’s) – is modified to enable perfusion through the vasculature; the attenuating elements of the stain are iodine, aluminum, and iron. After a 30-minute perfusion through the vasculature (10-minute …

Quantitative Study Of The Antimicrobial Effects Of Silver On The Motility Of Escherichia Coli, Benjamin Russell

Graduate Theses and Dissertations

In recent decades, the number of antibiotic-resistant bacterial infections has grown to become a serious global threat. This rise can be attributed to the widespread misuse of antibiotics and the lack of newly developed drugs to fight resistant organisms. Novel bactericidal substances have, therefore, garnered significant research interest. Silver, due to its powerful antimicrobial effects, is one such substance. Silver is typically most effective in cationic form; however, advancements in nanotechnology have paved the way for the controlled fabrication of nano-silver. Silver nanoparticles have been shown to have increased antibacterial potency for a variety of reasons, including the release of …

Accelerated 129xe Mri Morphometry Of Terminal Airspace Enlargement: Feasibility In Volunteers And Those With Alpha-1 Antitrypsin Deficiency, Alexei Ouriadov, Fumin Guo, David G Mccormack, Grace Parraga

Medical Biophysics Publications

PURPOSE: Multi-b diffusion-weighted hyperpolarized inhaled-gas MRI provides imaging biomarkers of terminal airspace enlargement including ADC and mean linear intercept (L

METHODS: We evaluated multi-b (0, 12, 20, 30, and 45.5 s/cm

RESULTS: For the HV subgroup, mean differences of 5%, 2%, and 8% were observed between fully sampled and undersampled k-space for ADC, L

CONCLUSIONS: Accelerated multi-b diffusion-weighted

Synergistic Toxicity In An In Vivo Model Of Neurodegeneration Through The Co-Expression Of Human Tdp-43M337v And TauT175d Protein, Alexander J. Moszczynski, Madeline Harvey, Niveen Fulcher, Cleusa De Oliveira, Patrick Mccunn, Neil Donison, Robert Bartha, Susanne Schmid, Michael J. Strong, Kathryn Volkening

Medical Biophysics Publications

Although it has been suggested that the co-expression of multiple pathological proteins associated with neurodegeneration may act synergistically to induce more widespread neuropathology, experimental evidence of this is sparse. We have previously shown that the expression of Thr175Asp-tau (tauT175D) using somatic gene transfer with a stereotaxically-injected recombinant adeno-associated virus (rAAV9) vector induces tau pathology in rat hippocampus. In this study, we have examined whether the co-expression of human tauT175D with mutant human TDP-43 (TDP-43M337V) will act synergistically. Transgenic female Sprague-Dawley rats that inducibly express mutant human TDP-43M337V using the choline acetyltransferase (ChAT) tetracycline response element (TRE) driver with activity modulating …

Normalisation Of Mri Ventilation Heterogeneity In Severe Asthma By Dupilumab, Sarah Svenningsen, Ehsan Ahmed Haider, Rachel L Eddy, Grace Parraga, Parameswaran Nair

Medical Biophysics Publications

Ventilation heterogeneity in asthma could be due to many reasons. Luminal obstruction due to inflammatory cells or mucus, smooth muscle constriction and airway wall thickness could all contribute individually or collectively to ventilation heterogeneity. Interleukin-4 and interleukin-13, acting through the common interleukin-4 receptor, have the potential to modulate all of these features of asthma.1 Inhaled hyperpolarised gas MRI provides a way to regionally visualise and quantify the functional consequence of these features.2 Dupilumab is a fully human monoclonal antibody directed against the alpha-subunit of the interleukin-4 receptor.3 Here, we report a severe asthmatic who showed significant improvement and normalisation of …

Ventricular Volume Expansion In Presymptomatic Genetic Frontotemporal Dementia, Tamara P. Tavares, Derek G.V. Mitchell, Kristy Coleman, Christen Shoesmith, Robert Bartha, David M. Cash, Katrina M. Moore, John Van Swieten, Barbara Borroni, Daniela Galimberti, Maria Carmela Tartaglia, James Rowe, Caroline Graff, Fabrizio Tagliavini, Giovanni Frisoni, Stefano Cappa, Robert Laforce, Alexandre De Mendonça, Sandro Sorbi, Garrick Wallstrom, Mario Masellis, Jonathan D. Rohrer, Elizabeth C. Finger

Medical Biophysics Publications

Copyright © 2019 American Academy of Neurology. ObjectiveTo characterize the time course of ventricular volume expansion in genetic frontotemporal dementia (FTD) and identify the onset time and rates of ventricular expansion in presymptomatic FTD mutation carriers.MethodsParticipants included patients with a mutation in MAPT, PGRN, or C9orf72, or first-degree relatives of mutation carriers from the GENFI study with MRI scans at study baseline and at 1 year follow-up. Ventricular volumes were obtained from MRI scans using FreeSurfer, with manual editing of segmentation and comparison to fully automated segmentation to establish reliability. Linear mixed models were used to identify differences in ventricular …

Chronic Obstructive Pulmonary Disease: Thoracic Ct Texture Analysis And Machine Learning To Predict Pulmonary Ventilation, Andrew Westcott, Dante P I Capaldi, David G Mccormack, Aaron D Ward, Aaron Fenster, Grace Parraga

Medical Biophysics Publications

Background Fixed airflow limitation and ventilation heterogeneity are common in chronic obstructive pulmonary disease (COPD). Conventional noncontrast CT provides airway and parenchymal measurements but cannot be used to directly determine lung function. Purpose To develop, train, and test a CT texture analysis and machine-learning algorithm to predict lung ventilation heterogeneity in participants with COPD. Materials and Methods In this prospective study (

Visualization Of The Small Airways:What It Is And Why It Matters, Mark L Schiebler, Grace Parraga

Medical Biophysics Publications

When the earth transitioned to an oxygen-containing atmosphere, many bacterial species were killed by the free radicals that developed in their cytoplasm. New life forms took advantage of this change by evolving to use oxygen as the final resting place for electrons involved in the Krebs cycle. Animals today rely on getting oxygen into the blood stream and getting carbon dioxide out by ventilation through sequentially smaller and smaller tubes until diffusion takes over, finally reaching the terminal respiratory bronchiole and its associated alveoli for gas exchange. All animals are obligate aerobes. One group has estimated that there are 274 …

Cardiovascular Risk Scoring And Magnetic Resonance Imaging Detected Subclinical Cerebrovascular Disease, Sonia S Anand, Jack V Tu, Dipika Desai, Phillip Awadalla, Paula Robson, Sébastien Jacquemont, Trevor Dummer, Nhu Le, Louise Parker, Paul Poirier, Koon Teo, Scott A Lear, Salim Yusuf, Jean-Claude Tardif, Francois Marcotte, David Busseuil, Jean-Pierre Després, Sandra E Black, Anish Kirpalani, Grace Parraga, Michael D Noseworthy, Alexander Dick, Jonathan Leipsic, David Kelton, Jennifer Vena, Melissa Thomas, Karleen M Schulze, Eric Larose, Alan R Moody, Eric E Smith, Matthias G Friedrich

Medical Biophysics Publications

AIMS: Cardiovascular risk factors are used for risk stratification in primary prevention. We sought to determine if simple cardiac risk scores are associated with magnetic resonance imaging (MRI)-detected subclinical cerebrovascular disease including carotid wall volume (CWV), carotid intraplaque haemorrhage (IPH), and silent brain infarction (SBI).

METHODS AND RESULTS: A total of 7594 adults with no history of cardiovascular disease (CVD) underwent risk factor assessment and a non-contrast enhanced MRI of the carotid arteries and brain using a standardized protocol in a population-based cohort recruited between 2014 and 2018. The non-lab-based INTERHEART risk score (IHRS) was calculated in all participants; the …

Eliminating The Effects Of Motion During Radiofrequency Lesion Delivery Using A Novel Contact-Force Controller., Daniel Gelman, Allan C Skanes, Douglas L Jones, Michael Timofeyev, Tal Bar-On, Maria Drangova

Medical Biophysics Publications

INTRODUCTION: Catheter-tissue contact force is a determinant of radiofrequency (RF) ablation lesion effectiveness. However, ablation on a beating heart is subject to force variability, making it difficult to optimally deliver consistently durable and transmural lesions. This work evaluates improvements in contact force stability and lesion reproducibility by using a catheter contact-force controller (CFC) during lesion delivery in vitro and in vivo.

METHODS AND RESULTS: Using a sheath and force-sensing catheter, an experienced operator attempted to maintain a constant force of 20 g at targets within the atria and left ventricle of a pig manually and using the CFC; the average …

Development Of A Stand-Alone Dcs System For Monitoring Absolute Cerebral Blood Flow, Mahro Khalid, Daniel Milej, Ajay Rajaram, Androu Abdalmalak, Laura Morrison, Mamadou Diop, Keith S.T. Lawrence

Medical Biophysics Publications

© 2019 Optical Society of America. Diffuse correlation spectroscopy (DCS) is a noninvasive optical technique for monitoring cerebral blood flow (CBF). This work presents a stand-alone DCS system capable of monitoring absolute CBF by incorporating a quantitative dynamic contrast-enhanced (DCE) technique. Multi-distance data were acquired to measure the tissue optical properties and to perform DCE experiments. Feasibility of the technique was assessed in piglets in which the optical properties were measured independently by time-resolved near-infrared spectroscopy. A strong linear correlation was observed between CBF values derived using the two sets of optical properties, demonstrating that this hybrid DCS approach can …

Evaluation Of Hyperspectral Nirs For Quantitative Measurements Of Tissue Oxygen Saturation By Comparison To Time-Resolved Nirs, Matthew Kewin, Ajay Rajaram, Daniel Milej, Androu Abdalmalak, Laura Morrison, Mamadou Diop, Keith St Lawrence

Medical Biophysics Publications

© 2019 Optical Society of America. Near-infrared spectroscopy (NIRS) is considered ideal for brain monitoring during preterm infancy because it is non-invasive and provides a continuous measure of tissue oxygen saturation (StO2). Hyperspectral NIRS (HS NIRS) is an inexpensive, quantitative modality that can measure tissue optical properties and oxygen saturation (StO2) by differential spectroscopy. In this study, experiments were conducted using newborn piglets to measure StO2 across a range of oxygenation levels from hyperoxia to hypoxia by HS and time-resolved (TR) NIRS for validation. A strong correlation between StO2 measurements from the two techniques was observed (R2 = 0.98, average …

Hyperpolarized Helium 3 Mri In Mild-To-Moderate Asthma: Prediction Of Postbronchodilator Reversibility, Rachel L Eddy, Sarah Svenningsen, Christopher Licskai, David G Mccormack, Grace Parraga

Medical Biophysics Publications

Background: Longitudinal progression to irreversible airflow limitation occurs in approximately 10% of patients with asthma, but it is difficult to identify patients who are at risk for this transition.

Purpose: To investigate 6-year longitudinal changes in hyperpolarized helium 3 (3He) MRI ventilation defects in study participants with mild-to-moderate asthma and identify predictors of longitudinal changes in postbronchodilator forced expiratory volume in 1 second (FEV1) reversibility

Materials and Methods: Spirometry and hyperpolarized 3He MRI were evaluated in participants with mild-to-moderate asthma in two prospectively planned visits approximately 6 years apart. Participants underwent methacholine challenge at baseline (January 2010 to April 2011) …

Methodological Consensus On Clinical Proton Mrs Of The Brain: Review And Recommendations, Martin Wilson, Ovidiu Andronesi, Peter B. Barker, Robert Bartha, Alberto Bizzi, Patrick J. Bolan, Kevin M. Brindle, In Young Choi, Cristina Cudalbu, Ulrike Dydak, Uzay E. Emir, Ramon G. Gonzalez, Stephan Gruber, Rolf Gruetter, Rakesh K. Gupta, Arend Heerschap, Anke Henning, Hoby P. Hetherington, Petra S. Huppi, Ralph E. Hurd, Kejal Kantarci, Risto A. Kauppinen, Dennis W.J. Klomp, Roland Kreis, Marijn J. Kruiskamp, Martin O. Leach, Alexander P. Lin, Peter R. Luijten, Małgorzata Marjańska, Andrew A. Maudsley, Dieter J. Meyerhoff, Carolyn E. Mountford

Medical Biophysics Publications

© 2019 International Society for Magnetic Resonance in Medicine Proton MRS (1H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good-quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a …

Characterization Of A Non-Contact Imaging Scintillator-Based Dosimetry System For Total Skin Electron Therapy., Irwin I. Tendler, Petr Bruza, Michael Jermyn, Xu Cao, Benjamin B. Williams, Lesley A. Jarvis, Brian W. Pogue, David J. Gladstone

Dartmouth Scholarship

Surface dosimetry is required for ensuring effective administration of total skin electron therapy (TSET); however, its use is often reduced due to the time consuming and complex nature of acquisition. A new surface dose imaging technique was characterized in this study and found to provide accurate, rapid and remote measurement of surface doses without the need for post-exposure processing. Disc-shaped plastic scintillators (1 mm thick  ×  15 mm [Formula: see text]) were chosen as optimal-sized samples and designed to attach to a flat-faced phantom for irradiation using electron beams. Scintillator dosimeter response to radiation damage, dose rate, and temperature were …

Scintillation Event Localization In Novel Hemi-Ellipsoid Detector For Spect, Hanif R. Soysal

LSU Master's Theses

A high sensitivity Cardiac SPECT system using hemi-ellipsoid crystals with pinhole collimation was previously proposed by Dey et al. To investigate detector resolution for this design, the scintillation light spread on a monolithic hemi-ellipsoidal CsI crystal was simulated using Geant4 Monte Carlo. The expected distribution of scintillation light on the outer surface of the crystal from photoelectric absorption events was obtained from the simulations for selected points inside the crystal. Two sets of simulations were performed. For the first set, a look-up table (LUT) of 12 points was created and each point mapped to its expected light distribution—four points at …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Functional Network Resilience To Pathology In Presymptomatic Genetic Frontotemporal Dementia, Timothy Rittman, Robin Borchert, Simon Jones, John Van Swieten, Barbara Borroni, Daniela Galimberti, Mario Masellis, Maria Carmela Tartaglia, Caroline Graff, Fabrizio Tagliavini, Giovanni B. Frisoni, Robert Laforce, Elizabeth Finger, Alexandre Mendonça, Sandro Sorbi, Jonathan D. Rohrer, James B. Rowe, Sónia Afonso, Maria Rosario Almeida, Sarah Anderl-Straub, Christin Andersson, Anna Antonell, Silvana Archetti, Andrea Arighi, Mircea Balasa, Myriam Barandiaran, Nuria Bargalló, Robart Bartha, Benjamin Bender, Luisa Benussi, Valentina Bessi, Giuliano Binetti

Medical Biophysics Publications

© 2019 The Authors The presymptomatic phase of neurodegenerative diseases are characterized by structural brain changes without significant clinical features. We set out to investigate the contribution of functional network resilience to preserved cognition in presymptomatic genetic frontotemporal dementia. We studied 172 people from families carrying genetic abnormalities in C9orf72, MAPT, or PGRN. Networks were extracted from functional MRI data and assessed using graph theoretical analysis. We found that despite loss of both brain volume and functional connections, there is maintenance of an efficient topological organization of the brain's functional network in the years leading up to the estimated age …

Signal Intensity Analysis And Optimization For In Vivo Imaging Of Cherenkov And Excited Luminescence., Ethan P. M. Larochelle, Jennifer R. Shell, Jason R. Gunn, Scott C. Davis, Brian W. Pogue

Dartmouth Scholarship

During external beam radiotherapy (EBRT), in vivo Cherenkov optical emissions can be used as a dosimetry tool or to excite luminescence, termed Cherenkov-excited luminescence (CEL) with microsecond-level time-gated cameras. The goal of this work was to develop a complete theoretical foundation for the detectable signal strength, in order to provide guidance on optimization of the limits of detection and how to optimize near real time imaging. The key parameters affecting photon production, propagation and detection were considered and experimental validation with both tissue phantoms and a murine model are shown. Both the theoretical analysis and experimental data indicate that the …

Evaluation Of Ventilation Assistance For Improving Respiratory Reproducibility In Radiation Therapy, Cameron J. Sprowls

LSU Master's Theses

Background: Respiratory motion affects all tumor sites in the thorax and abdomen. Variations of the respiratory pattern cause variations of the tumor motion which can result in differences between the planned and delivered dose distributions. Previous breathing guidance techniques have been investigated to improve respiratory reproducibility; however, ventilation assistance has not been investigated. We evaluated using bi-level positive airway pressure (BIPAP) ventilation assistance for improving respiratory reproducibility in patients with tumor sites impacted by respiratory motion.

Methods: Written informed consent was obtained for 10 patients currently undergoing radiation therapy treatment. Patients participated in sessions over their course of treatment, which …

Reproducibility Of Neurite Orientation Dispersion And Density Imaging (Noddi) In Rats At 9.4 Tesla, Patrick Mccunn, Kyle M. Gilbert, Peter Zeman, Alex X. Li, Michael J. Strong, Ali R. Khan, Robert Bartha

Medical Biophysics Publications

© 2019 McCunn et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Purpose Neurite Orientation Dispersion and Density Imaging (NODDI) is a diffusion MRI (dMRI) technique used to characterize tissue microstructure by compartmental modelling of neural water fractions. Intra-neurite, extra-neurite, and cerebral spinal fluid volume fractions are measured. The purpose of this study was to determine the reproducibility of NODDI in the rat brain at 9.4 Tesla. Methods Eight data sets were successfully …

Probiotic Administration As An Adjuvant Therapeutic Treatment For Anxiety, Depression, And Cognitive Impairment Among Hypothyroid Patients, Erin R. Gorman

Selected Honors Theses

Hypothyroidism is a form of thyroid dysfunction that occurs when the thyroid gland does not make and secrete enough thyroid hormones to regulate certain processes in the body. Because thyroid hormones take part in many bodily functions, hypothyroidism can cause a large range of symptoms. Current research indicates that some strains of probiotics have beneficial effects on certain neurological and inflammatory diseases, leading to the impression that they can be used therapeutically for effective treatment of different mental health issues such as anxiety, stress, depression, and impaired memory. Because hypothyroidism often leads to such mental symptoms, it may be possible …

The Effect Of Sepsis On Cerebral Microvascular Blood Flow, Laura Mawdsley, Mamadou Diop, Chris G. Ellis

Western Research Forum

Background: Sepsis is a dysregulated host response to infection that affects 18 000 000 people worldwide, and over 325 000 000 dollars are spent treating sepsis in Canada every year. One of the symptoms of severe sepsis is an altered mental state, which is accompanied with a measured decrease in oxygen levels in the skeletal muscle microvasculature. It is hypothesized that his altered mental state is due to a lack of oxygenated blood reaching the brain.

Hypothesis: After the onset of sepsis, microvascular cerebral blood flow and oxygen levels in the blood will decrease. Onset of decreased blood flow in …

Ambroxol As A Novel Disease-Modifying Treatment For Parkinson's Disease Dementia: Protocol For A Single-Centre, Randomized, Double-Blind, Placebo-Controlled Trial, C. R.A. Silveira, J. Mackinley, K. Coleman, Z. Li, E. Finger, R. Bartha, S. A. Morrow, J. Wells, M. Borrie, R. G. Tirona, C. A. Rupar, G. Zou, R. A. Hegele, D. Mahuran, Penny A. Macdonald, M. E. Jenkins, M. Jog, S. H. Pasternak

Medical Biophysics Publications

© 2019 The Author(s). Background: Currently there are no disease-modifying treatments for Parkinson's disease dementia (PDD), a condition linked to aggregation of the protein α-synuclein in subcortical and cortical brain areas. One of the leading genetic risk factors for Parkinson's disease is being a carrier in the gene for β-Glucocerebrosidase (GCase; gene name GBA1). Studies in cell culture and animal models have shown that raising the levels of GCase can decrease levels of α-synuclein. Ambroxol is a pharmacological chaperone for GCase and is able to raise the levels of GCase and could therefore be a disease-modifying treatment for PDD. The …

Dynamic Light Scattering Optical Coherence Tomography To Probe Motion Of Subcellular Scatterers., Nico J J Arezza, Marjan Razani, Michael C Kolios

Medical Biophysics Publications

Optical coherence tomography (OCT) is used to provide anatomical information of biological systems but can also provide functional information by characterizing the motion of intracellular structures. Dynamic light scattering OCT was performed on intact, control MCF-7 breast cancer cells and cells either treated with paclitaxel to induce apoptosis or deprived of nutrients to induce oncosis. Autocorrelations (ACs) of the temporal fluctuations of OCT intensity signals demonstrate a significant decrease in decorrelation time after 24 h in both the paclitaxel-treated and nutrient-deprived cell groups but no significant differences between the two groups. The acquired ACs were then used as input for …