Traditional Posters: Miscellaneous
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| Hargun Sohi1, Seth Ruffins1, Yang Chai2, Scott Fraser1, Russell Jacobs3
1Caltech; 2USC; 3Caltech, Pasadena, CA, United States Microscopic MRI (μMRI) is an emerging technique for high-throughput phenotyping of transgenic mouse embryos, and is capable of visualizing abnormalities in craniofacial development. μMRI methods rely on reduction of the tissue T1 relaxation time by penetration of a gadolinium chelate contrast agent. The use of contrast agents is aimed at reducing the T1 relaxation time of the sample thus permitting a decrease in acquisition scan time, and/or increase in image signal-to-noise ratio (SNR), and/or increase in spatial resolution. In this work we apply these technologies to delineating changes in a murine cleft palate model system. 1041. Relaxivity Tissue Differentiation Among Gd-Based Contrast Agents in Ex-Vivo Mouse Embryo Imaging Michael David Wong1, X Josette Chen1, R Mark Henkelman1 1Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada The role of MRI in developmental biology, specifically in mouse embryo organogenesis and phenotyping, is significantly increasing due to technologies that allow for high image resolution and throughput. The majority of ex-vivo MRI mouse embryo studies improve image contrast and SNR by immersing the sample into some concentration of Gd-based contrast agent. It is widely believed that all gadolinium-based contrast agents have identical tissue interactions and provide similar MRI images despite the differences in Gd-chelates. Here, relaxivity (r1) variation amongst mouse embryo organs is observed for one class of contrast agents, while homogeneity is seen throughout the embryo for another. 1042. Contrast Enhancement in Preserved Zebra Finch Brains Utilizing Low Temperatures at High Magnetic Fields Parastou Foroutan1,2, Susanne L. T. Cappendijk3, Samuel C. Grant1,2 1Chemical & Biomedical Engineering, The Florida State University, Tallahassee, FL, United States; 2CIMAR, The National High Magnetic Field Laboratory, Tallahassee, FL, United States; 3Biomedical Sciences, College of Medicine, The Florida State University, Tallahassee, FL, United States Temperature is evaluated as an easy method of increasing contrast in preserved tissue. In this study, excised, fixed brains from the adult male zebra finch were scanned at multiple temperatures between 5-25 Celsius. Relaxation (T1, T2 and T2*), signal-to-noise, relative contrast and contrast-to-noise were measured at each temperature. In addition, high-resolution 3D gradient recalled echo scans were acquired at 40-micron isotropic resolution at each temperature. Although all relaxation mechanisms displayed decreases with temperature, only T2* contrast displayed structural enhancement. The ramifications of these findings are discussed with respect to microimaging studies of preserved tissue samples. 1043. Phenotyping a Novel Mouse Model of Congenital Heart Disease Using μMRI Jon Orlando Cleary1,2, Francesca C. Norris3,4, Karen McCue5, Anthony N. Price3, Sarah Beddow5, Roger J. Ordidge2,6, Peter J. Scambler5, Mark F. Lythgoe3 1Centre for Advanced Biomedical Imaging, Department of Medicine and UCL Institute of Child Health , University College London, London, United Kingdom; 2Department of Medical Physics and Bioengineering, University College London, London, United Kingdom; 3Centre for Advanced Biomedical Imaging, Department of Medicine and UCL Institute of Child Health, University College London, London, United Kingdom; 4Centre for Mathematics and Physics in the Life Sciences and EXperimental Biology (CoMPLEX), University College London, London, United Kingdom; 5Molecular Medicine Unit, UCL Institute of Child Health, University College London, London, United Kingdom; 6Wellcome Trust Advanced MRI Laboratory, University College London, London, United Kingdom CHARGE and DiGeorge syndromes are conditions associated with haploinsufficiency of specific genes (CHD7 and TBX1) and are characterised by cardiovascular defects. Knockout mice are an important tool in genetic studies, allowing genes implicated in congenital defects to be identified and characterised. Micro-MRI is an emerging technique for high-resolution cardiac phenotyping, enabling the acquisition of 3D images of multiple embryo in a single scan. Given the phenotypic overlap of these conditions, we examined heart morphology in novel double-knockout mouse embryos (Chd7+/-Tbx1+/-), performing an assessment using MRI. In particular, we identified an increased incidence of ventricular septal defects in these mice. 1044. Optimised µMRI for Phenotyping the Tc1 Model of Down Syndrome Jon Orlando Cleary*1,2, Francesca C. Norris*3,4, Frances K. Wiseman5, Anthony N. Price3, ManKin Choy3, Victor L.J. Tybulewicz6, Roger J. Ordidge2,7, Elizabeth M.C. Fisher5, Mark F. Lythgoe3 1Centre for Advanced Biomedical Imaging, Department of Medicine and UCL Institute of Child Health , University College London, London, United Kingdom; 2Department of Medical Physics and Bioengineering, University College London, London, United Kingdom; 3Centre for Advanced Biomedical Imaging, Department of Medicine and UCL Institute of Child Health, University College London, London, United Kingdom; 4Centre for Mathematics and Physics in the Life Sciences and EXperimental Biology (CoMPLEX), University College London, London, United Kingdom; 5Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, London, United Kingdom; 6MRC National Insitiute for Health Research, London, United Kingdom; 7Wellcome Trust Advanced MRI Laboratory, University College London, London, *equal contribution ‘Staining’ brain tissue with MR contrast agents is a key part of MR microscopy, enabling enhanced delineation of structures. Although excised brains allow agent to quickly penetrate into tissue, brains left in-skull are less susceptible to damage during tissue extraction and imaging, resulting in more accurate morphometric analyses. We sought to develop an optimised preparation and scanning protocol for imaging adult mouse brains in-skull, determining the timecourse for agent to penetrate into intact brain. Using this protocol we assessed phenotype in Tc1 mice – a model of Down Syndrome. We identified ventricular enlargement in 10 of 14 transgenic Tc1+ mice imaged. 1045. MR Microscopy of Zebrafish Yüklə 355,76 Kb. Dostları ilə paylaş:
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