Download or read book Magnetic Resonance Imaging Techniques for Rodent Pulmonary Imaging written by Eriko Suzanne Yoshimaru and published by . This book was released on 2013 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Resonance Imaging (MRI) is a safe and widely used diagnostic imaging method that allows in vivo observation of anatomy and characterization of tissues. MRI provides a method to monitor patients without invasive measures, making it suitable for both diagnostics and longitudinal monitoring of various pathologies. A notable example of this is the work carried out by the Alzheimer's Disease Neuroimaging Initiative (ADNI), which utilizes imaging, including multiple MRI techniques, to monitor disease progression in AD patients and evaluates treatment responses and prevention strategies. Similarly, MRI has been extensively used in evaluating diseases in a variety of animal models. In order to detect subtle anatomical changes over time, small differences in MR images must be accurately extracted. Furthermore, to ensure that the extracted differences are due to anatomical changes rather than equipment variance, it becomes essential to monitor and to assess the MRI system stability. In the first chapter of the dissertation, a method for monitoring pre-clinical MRI system performance is discussed. The technique developed during the study provides a fast and simple method to monitor pre-clinical MRI systems but also has applications for all areas of MRI. The second chapter describes the development of a 3D UTE MRI method for pulmonary imaging in freely breathing mice. The development of the 3D UTE sequence for pulmonary MRI has demonstrated its ability to collect images without noticeable motion artifacts and with appreciable signal from the lung parenchyma. Furthermore, images at two distinct respiratory phases were reconstructed from a single data set, providing functional information of the rodents' lungs. Finally, in the third chapter, 3D 19F UTE MRI is evaluated for imaging in vivo distributions of perfluorocarbon (PFC) nanoemulsions for measuring pulmonary inflammation. Building upon the development of pulmonary imaging, fluorinated contrast agents made from PFCs were used to target immune cells in response to pulmonary pathology. Both 3D 1H and 19F UTE MRI were used to acquire pulmonary images of mouse models documented to have pulmonary pathology. Even though the mice had confirmed elevation in alveolar macrophage counts, no visible 19F signal accumulation within the pulmonary tissue was observed with MRI.

Download or read book Lung Magnetic Resonance Imaging as a Non invasive Alternative to Assess Experimental Pulmonary Diseases in Small Rodents written by François-Xavier Blé and published by . This book was released on 2007 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is able to detect water content in the biological tissue and thus to non-invasively assess on a regional basis infiltrated water and/or secreted fluids and/or tissue densification. In pulmonary diseases such as asthma, chronic obstructive pulmonary diseases or fibrosis, plasma exudation, mucus secretion and thickening of the lung tissue constitute hallmarks of the pathological status that directly contribute to functional impairment. These features are well conserved in experimental pulmonary disease models in the small rodents. A particular interest is given to murine models that have provided, in parallel to the technological progress in genetic engineering and molecular biology, a reliable in vivo support for lung disease understanding and investigation. Nowadays, routine methods used to evaluate disease state of the lung in these models are either terminal or gives functional estimation of the global airways.Therefore, we have set up a method using MRI technique to non-invasively depict different hallmarks occurring in a murine model of asthma. In this thesis, we have demonstrated that proton MRI provides a relevant mean to assess and follow signals associated with the plasma leakage and mucus secretions in the lung, which are both important features of the inflammatory response following allergenic provocation. To further confirm these findings, we have also validated in this model the effect of pharmacological tools. We chose to study sphingosine-1-phosphate (S1P) pharmacology on the basis of recent publications indicating a possible implication of this endogenous mediator in inflammation and lung barrier integrity in models of asthma. In two studies examining the effects of the general S1P agonist FTY720 and of the S1P2 antagonist JTE013, the incidence of plasma leakage on fluid signal detection was highlighted in our murine model of airway inflammation and confirmed by histology and BAL fluid analyses. Additionally, since the technique had been previously set up in the rat, we extended the knowledge in this species. In this regard, we achieved the selective detection and monitoring of mucus dynamics by MRI with the use of a specific contrast agent in a model of endotoxin-induced mucus hypersecretion. Besides, we also demonstrated the capabilities of MRI to follow the hydration of airway secretions. In this non-inflammatory model, the formation of MRI fluid signals were induced by hypertonic saline instillation and dose-dependently enhanced by different compounds that interact directly or indirectly with epithelial Na+ channel (ENaC), a major regulator of airway surface liquid hydration. These studies have been successfully performed in the rat with the perspective of future translation to murine models for transgenic application. Finally, we have partially validated the application of this technique to a less acute model, the murine bleomycin-induced fibrosis. This model has been chosen regarding its admitted relevance to mimic global characteristics of human pulmonary fibrosis in addition to its simplicity to be set up. In this study, we have been able to follow by MRI the course of edematous, mucous and/or fibrotic features in correlation with histological findings. In summary, the present work is bringing evidence of possible contributions of MRI in pulmonary disease investigations in mouse and rat, and postulates for its use to complete and/or replace the methods used nowadays to evaluate experimental murine models.

Download or read book Hyperpolarized Noble Gas Magnetic Resonance Imaging and Dynamic Spectroscopy for Investigation of Rat Models of Lung Inflammation written by Matthew Stephen Fox and published by . This book was released on 2012 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging of the lungs using non-ionizing approaches such as hyperpolarized 3He and 129Xe magnetic resonance imaging (MRI) is a useful tool both for research and clinical applications. This work focused on development of 129Xe MRI techniques to investigate inflammation in rat lungs. A rodent model of inflammation, specifically radiationinduced lung injury (RILI) was developed using a collimated 60Co source. A quantitative MRI technique measuring absolute ventilated lung volume (values obtained from rats using the previously established 3He method and those obtained with 129Xe, the usefulness of 129Xe for future investigations of.

Download or read book Oxygen enhanced Magnetic Resonance Imaging of Mice Lungs written by Kristina Nancy Watt and published by . This book was released on 2007 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulmonary magnetic resonance (MR) imaging provides valuable information about lung anatomy and perfusion and ventilation physiology. Oxygen-enhanced MR imaging visualizes the effect of ventilation using inhaled molecular oxygen as a T1-shortening contrast agent. The technique is challenged, however, by low proton density of lung tissue and cardiopulmonary physiology that result in reduced MR signal and increased motion artifacts. With the growing interest in mouse models of respiratory disease, application of human pulmonary MR techniques to mice is highly desirable. The purpose of this work was to develop oxygen-enhanced MR imaging as a non-invasive tool to examine ventilation in free-breathing mice. An optimized cardiac-triggered, respiratory-gated fast spin echo sequence was developed for oxygen-enhanced MR and successfully demonstrated in normal mice. Ventilation was visualized as significant signal enhancement in the lung parenchyma with pure oxygen inhalation. This sequence shows potential for application to studies of abnormal ventilation in models of pulmonary disease.

Download or read book New Techniques and Optimizations of Short Echo time 1H MRI with Applications in Murine Lung written by Jinbang Guo and published by . This book was released on 2016 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although x-ray computed tomography (CT) is a gold standard for pulmonary imaging, it has high ionizing radiation, which puts patients at greater risk of cancer, particularly in a longitudinal study with cumulative doses. Magnetic resonance imaging (MRI) doesn't involve exposure to ionizing radiation and is especially useful for visualizing soft tissues and organs such as ligaments, cartilage, brain, and heart. Many efforts have been made to apply MRI to study lung function and structure of both humans and animals. However, lung is a unique organ and is very different from other solid organs like the heart and brain due to its complex air-tissue interleaved structure. The magnetic susceptibility differences at the air-tissue interfaces result in very short T2* (~1 ms) of lung parenchyma, which is even shorter in small-animal MRI (often at higher field) than in human MRI. Both low proton density and short T2* of lung parenchyma are challenges for pulmonary imaging via MRI because they lead to low signal-to-noise ratio (SNR) in images with traditional Cartesian methods that necessitate longer echo times ({u2265} 1 ms). This dissertation reports the work of optimizing pulmonary MRI techniques by minimizing the negative effects of low proton density and short T2* of murine lung parenchyma, and the application of these techniques to imaging murine lung. Specifically, echo time (TE) in the Cartesian sequence is minimized, by simultaneous slice select rephasing, phase encoding and read dephasing gradients, in addition to partial Fourier imaging, to reduce signal loss due to T2* relaxation. Radial imaging techniques, often called ultra-short echo-time MRI or UTE MRI, with much shorter time between excitation and data acquisition, were also developed and optimized for pulmonary imaging. Offline reconstruction for UTE data was developed on a Linux system to regrid the non-Cartesian (radial in this dissertation) k-space data for fast Fourier transform. Slab-selected UTE was created to fit the field-of-view (FOV) to the imaged lung without fold-in aliasing, which increases TE slightly compared to non-slab-selected UTE. To further reduce TE as well as fit the FOV to the lung without aliasing, UTE with ellipsoidal k-space coverage was developed, which increases resolution and decreases acquisition time. Taking into account T2* effects, point spread function (PSF) analysis was performed to determine the optimal acquisition time for maximal single-voxel SNR. Retrospective self-gating UTE was developed to avoid the use of a ventilator (which may cause lung injury) and to avoid possible prospective gating errors caused by abrupt body motion. Cartesian gradient-recalled-echo imaging (GRE) was first applied to monitor acute cellular rejection in lung transplantation. By repeated imaging in the same animals, both parenchymal signal and lung compliance were measured and were able to detect rejection in the allograft lung. GRE was also used to monitor chronic cellular rejection in a transgenic mouse model after lung transplantation. In addition to parenchymal signal and lung compliance, the percentage of high-density lung parenchyma was defined and measured to detect chronic rejection. This represents one of the first times quantitative pulmonary MRI has been performed. For 3D radial UTE MRI, 2D golden means (1) were used to determine the direction of radial spokes in k-space, resulting in pseudo-random angular sampling of spherical k-space coverage. Ellipsoidal k-space coverage was generated by expanding spherical coverage to create an ellipsoid in k-space. UTE MRI with ellipsoidal k-space coverage was performed to image healthy mice and phantoms, showing reduced FOV and enhanced in-plane resolution compared to regular UTE. With this modified UTE, T2* of lung parenchyma was measured by an interleaved multi-TE strategy, and T1 of lung parenchyma was measured by a limited flip angle method (2). Retrospective self-gating UTE with ellipsoidal k-space coverage was utilized to monitor the progression of pulmonary fibrosis in a transforming growth factor (TGF)-[alpha] transgenic mouse model and compared with histology and pulmonary mechanics. Lung fibrosis progression was not only visualized by MRI images, but also quantified and tracked by the MRI-derived lung function parameters like mean lung parenchyma signal, high-density lung volume percentage, and tidal volume. MRI-derived lung function parameters were strongly correlated with the findings of pulmonary mechanics and histology in measuring fibrotic burden. This dissertation demonstrates new techniques and optimizations in GRE and UTE MRI that are employed to minimize TE and image murine lungs to assess lung function and structure and monitor the time course of lung diseases. Importantly, the ability to longitudinally image individual animals by these MRI techniques minimizes the number of animals required in preclinical studies and increases the statistical power of future experiments as each animal can serve at its own control.

Download or read book Hyperpolarized Noble Gas Magnetic Resonance Imaging of the Ex Vivo Rodent Lung written by D. M. L. Lilburn and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Application of Parallel Imaging to Murine Magnetic Resonance Imaging written by Chieh-Wei Chang and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of parallel imaging techniques for image acceleration is now common in clinical magnetic resonance imaging (MRI). There has been limited work, however, in translating the parallel imaging techniques to routine animal imaging. This dissertation describes foundational level work to enable parallel imaging of mice on a 4.7 Tesla/40 cm bore research scanner. Reducing the size of the hardware setup associated with typical parallel imaging was an integral part of achieving the work, as animal scanners are typically small-bore systems. To that end, an array element design is described that inherently decouples from a homogenous transmit field, potentially allowing for elimination of typically necessary active detuning switches. The unbalanced feed of this "dual-plane pair" element also eliminates the need for baluns in this case. The use of the element design in a 10-channel adjustable array coil for mouse imaging is presented, styled as a human cardiac top-bottom half-rack design. The design and construction of the homogenous transmit birdcage coil used is also described, one of the necessary components to eliminating the active detuning networks on the array elements. In addition, the design of a compact, modular multi-channel isolation preamplifier board is described, removing the preamplifiers from the elements and saving space in the bore. Several additions/improvements to existing laboratory infrastructure needed for parallel imaging of live mice are also described, including readying an animal preparation area and developing the ability to maintain isoflurane anesthesia delivery during scanning. In addition, the ability to trigger the MRI scanner to the ECG and respiratory signals from the mouse in order to achieve images free from physiological motion artifacts is described. The imaging results from the compact 10-channel mouse array coils are presented, and the challenges associated with the work are described, including difficulty achieving sample-loss dominance and signal-to-noise ratio (SNR) limitations. In conclusion, in vivo imaging of mice with cardiac and respiratory gating has been demonstrated. Compact array coils tailored for mice have been studied and potential future work and design improvements for our lab in this area are discussed. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148107

Download or read book MRI of the Lung written by Hans-Ulrich Kauczor and published by Springer Science & Business Media. This book was released on 2008-10-28 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past decade significant developments have been achieved in the field of magnetic resonance imaging (MRI), enabling MRI to enter the clinical arena of chest imaging. Standard protocols can now be implemented on up-to-date scanners, allowing MRI to be used as a first-line imaging modality for various lung diseases, including cystic fibrosis, pulmonary hypertension and even lung cancer. The diagnostic benefits stem from the ability of MRI to visualize changes in lung structure while simultaneously imaging different aspects of lung function, such as perfusion, respiratory motion, ventilation and gas exchange. On this basis, novel quantitative surrogates for lung function can be obtained. This book provides a comprehensive overview of how to use MRI for imaging of lung disease. Special emphasis is placed on benign diseases requiring regular monitoring, given that it is patients with these diseases who derive the greatest benefit from the avoidance of ionizing radiation.

Download or read book Hyperpolarized Noble Gas Magnetic Resonance Imaging of the Ex Vivo Rodent Lung written by David M. L. Lilburn and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Resonance Imaging as a Non invasive Tool to Investigate Pulmonary and Renal Fibrosis in Small Rodents written by Christine Egger and published by . This book was released on 2015 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Imaging of Asthma Progression and Therapeutic Response in Mouse Lung Models written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mouse models have been a versatile tool in asthma research, however the application of imaging techniques to quantify hallmarks of asthma, to follow the course of the disease or to monitor treatment response are hampered by the small size of the mouse lung. Moreover, breathing causes substantial motion artifacts in most of the in-vivo imaging methods. In addition, the air-tissue interfaces within the lung causes scattering effects in optical imaging applications, the large cavity of the lung leads to susceptibility artifacts in magnetic resonance imaging and the rib cage hinders the use of ...

Download or read book Small Animal Imaging written by Fabian Kiessling and published by Springer Science & Business Media. This book was released on 2010-11-29 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Small animal imaging has been recognized as an important tool in preclinical research. Nevertheless, the results of non-invasive imaging are often disappointing owing to choice of a suboptimal imaging modality and/or shortcomings in study design, experimental setup, and data evaluation. This textbook is a practical guide to the use of non-invasive imaging in preclinical research. Each of the available imaging modalities is discussed in detail, with the assistance of numerous informative illustrations. In addition, many useful hints are provided on the installation of a small animal unit, study planning, animal handling, and the cost-effective performance of small animal imaging. Cross-calibration methods, data postprocessing, and special imaging applications are also considered in depth. This is the first book to cover all the practical basics in small animal imaging, and it will prove an invaluable aid for researchers, students, and technicians.

Download or read book Development of Magnetic Resonance Imaging Techniques for Mouse Models of Alzheimer s Disease written by James Martin O'Callaghan and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Small Animal Imaging written by Fabian Kiessling and published by Springer. This book was released on 2017-05-22 with total page 871 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook is a practical guide to the use of small animal imaging in preclinical research that will assist in the choice of imaging modality and contrast agent and in study design, experimental setup, and data evaluation. All established imaging modalities are discussed in detail, with the assistance of numerous informative illustrations. While the focus of the new edition remains on practical basics, it has been updated to encompass a variety of emerging imaging modalities, methods, and applications. Additional useful hints are also supplied on the installation of a small animal unit, study planning, animal handling, and cost-effective performance of small animal imaging. Cross-calibration methods and data postprocessing are considered in depth. This new edition of Small Animal Imaging will be an invaluable aid for researchers, students, and technicians involved in research into and applications of small animal imaging.

Download or read book Magnetic Resonance Spectroscopy of Degenerative Brain Diseases written by Gülin Öz and published by Springer. This book was released on 2016-07-27 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proposed book will act as a guide for scientists and clinicians to the unique information that MRS can provide. It will be a comprehensive overview of clinical and pre-clinical MRS applications and potential clinical utility of MRS biomarkers in degenerative brain diseases from leading experts in the field. MRS has proven to be a powerful complementary tool to MRI for the diagnosis and monitoring of disease progression and response to treatment because it can detect changes in cell density, cell type, and biochemical composition, not just structural changes. As the population in the developed world continues to age, neuroimaging for diagnosis, prognosis, and therapy monitoring of neurodegenerative diseases becomes increasingly important and there has been a recent surge of clinical and pre-clinical applications of MRS indicating that this technique can provide robust and non-invasive biomarkers of degeneration. ​

Download or read book Micro imaging of the Mouse Lung Via MRI written by Wei Wang and published by . This book was released on 2012 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative measurement of lung microstructure is of great significance in assessment of pulmonary disease, particularly in the earliest stages. Conventional stereological assessment of ex-vivo fixed tissue specimens under the microscope has a long and successful tradition and is regarded as a gold standard, but the invasive nature limits its applications and the practicality of use in longitudinal studies. The technique for diffusion MRI-based 3He lung morphometry was previously developed and validated for human lungs, and was recently extended to ex-vivo mouse lungs. The technique yields accurate, quantitative information about the microstructure and geometry of acinar airways. In this dissertation, the 3He lung morphometry technique is for the first time successfully implemented for in-vivo studies of mice. It can generate spatially-resolved maps of parameters that reveal the microstructure of mouse lung. Results in healthy mice indicate excellent agreement between in-vivo morphometry via 3He MRI and microscopic morphometry after sacrifice. The implementation and validation of 3He morphometry in healthy mice open up new avenues for application of the technique as a precise, noninvasive, in-vivo biomarker of changes in lung microstructure, within various mouse models of lung disease. We have applied 3He morphometry to the Sendai mouse model of lung disease. Specifically, the Sendai-virus model of chronic obstructive lung disease has demonstrated an innate immune response in mouse airways that exhibits similarities to the chronic airway inflammation in human COPD and asthma, but the effect on distal lung parenchyma had not been investigated. We imaged the time course and regional distribution of mouse lung microstructural changes in vivo after Sendai virus (SeV) infection with 1H and 3He diffusion MRI. 1H MR images detected the SeV-induced pulmonary inflammation in vivo and 3He lung morphometry showed modest increase in alveolar duct radius distal to airway inflammation, particularly in the lung periphery, indicating airspace enlargement after virus infection. Another important application of the imaging technique is the study of lung regeneration in a pneumonectomy (PNX) model. Partial resection of the lung by unilateral PNX is a robust model of compensatory lung growth. It is typically studied by postmortem morphometry in which longitudinal assessment in the same animal cannot be achieved. Here we successfully assess the microstructural changes and quantify the compensatory lung growth in vivo in the PNX mouse model via 1H and hyperpolarized 3He diffusion MRI. Our results show complete restoration in lung volume and total alveolar number with enlargement of alveolar size, which is consistent with prior histological studies conducted in different animals at various time points. This dissertation demonstrates that 3He lung morphometry has good sensitivity in quantifying small microstructural changes in the mouse lung and can be applied to a variety of mouse pulmonary models. Particularly, it has great potential to become a valuable tool in understanding the time course and the mechanism of lung growth in individual animals and may provide insight into post-natal lung growth and lung regeneration.

Download or read book The Use of Magnetic Resonance Imaging MRI to Assess Pulmonary Hypertension in Hypoxic Rats written by Nancy Rita Maxwell and published by . This book was released on 1989 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: