Download or read book Novel Techniques for Respiratory Motion Estimation and Modelling from Magnetic Resonance Data written by Christian Buerger and published by . This book was released on 2011 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging such as Magnetic Resonance (MR) imaging and Positron Emission Tomography (PET) are commonly used in the diagnosis and treatment follow-up of cancer. Respiratory motion, however, introduces motion blurring and degrades image quality. As a solution, motion models have been proposed but remain challenging due to the following problems. First, common motion estimation algorithms are computationally complex (and consequently time-consuming) and often have poor robustness when large deformations are present. Second, due to technical limitations of current MR systems, prospective acquisitions are not capable of acquiring images with both high temporal and spatial resolution, which are required for accurate motion estimations. In this thesis, both challenges are addressed. A new registration algorithm has been developed which estimates complex non-rigid motion by a combination of multiple local affine components. This algorithm allows fast and accurate motion estimations and is robust against large deformations due to its adaptive hierarchical structure. Furthermore, a new reconstruction scheme has been developed which retrospectively combines raw data acquired from free-breathing acquisitions to reconstruct multiple images covering the complete range of the breathing cycle. This reconstruction method overcomes the spatial-temporal trade-off and produces near motion-free respiratory images with high isotropic resolution. Both methods are combined to model the continuous deformation of the abdomen during an average breathing cycle, with errors in model predictions of comparable magnitude to the image resolution. A modification of this work is used to allow highly efficient motion compensated reconstructions from short acquisitions under free-breathing.

Download or read book Novel Techniques for Respiratory Motion Estimation and Modeling from MR Data written by Christian Buerger and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging such as Magnetic Resonance (MR) imaging and Positron Emission Tomography (PET) are commonly used in the diagnosis and treatment follow-up of cancer. Respiratory motion, however, introduces motion blurring and degrades image quality. As a solution, motion models have been proposed but remain challenging due to the following problems. First, common motion estimation algorithms are computationally complex (and consequently time-consuming) and often have poor robustness when large deformations are present. Second, due to technical limitations of current MR systems, prospective acquisitions are not capable of acquiring images with both high temporal and spatial resolution, which are required for accurate motion estimations. In this thesis, both challenges are addressed. A new registration algorithm has been developed which estimates complex non-rigid motion by a combination of multiple local affine components. This algorithm allows fast and accurate motion estimations and is robust against large deformations due to its adaptive hierarchical structure. Furthermore, a new reconstruction scheme has been developed which retrospectively combines raw data acquired from free-breathing acquisitions to reconstruct multiple images covering the complete range of the breathing cycle. This reconstruction method overcomes the spatial-temporal trade-off and produces near motion-free respiratory images with high isotropic resolution. Both methods are combined to model the continuous deformation of the abdomen during an average breathing cycle, with errors in model predictions of comparable magnitude to the image resolution. A modification of this work is used to allow highly efficient motion compensated reconstructions from short acquisitions under free-breathing.

Download or read book Prediction and Classification of Respiratory Motion written by Suk Jin Lee and published by Springer. This book was released on 2013-10-25 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes recent radiotherapy technologies including tools for measuring target position during radiotherapy and tracking-based delivery systems. This book presents a customized prediction of respiratory motion with clustering from multiple patient interactions. The proposed method contributes to the improvement of patient treatments by considering breathing pattern for the accurate dose calculation in radiotherapy systems. Real-time tumor-tracking, where the prediction of irregularities becomes relevant, has yet to be clinically established. The statistical quantitative modeling for irregular breathing classification, in which commercial respiration traces are retrospectively categorized into several classes based on breathing pattern are discussed as well. The proposed statistical classification may provide clinical advantages to adjust the dose rate before and during the external beam radiotherapy for minimizing the safety margin. In the first chapter following the Introduction to this book, we review three prediction approaches of respiratory motion: model-based methods, model-free heuristic learning algorithms, and hybrid methods. In the following chapter, we present a phantom study—prediction of human motion with distributed body sensors—using a Polhemus Liberty AC magnetic tracker. Next we describe respiratory motion estimation with hybrid implementation of extended Kalman filter. The given method assigns the recurrent neural network the role of the predictor and the extended Kalman filter the role of the corrector. After that, we present customized prediction of respiratory motion with clustering from multiple patient interactions. For the customized prediction, we construct the clustering based on breathing patterns of multiple patients using the feature selection metrics that are composed of a variety of breathing features. We have evaluated the new algorithm by comparing the prediction overshoot and the tracking estimation value. The experimental results of 448 patients’ breathing patterns validated the proposed irregular breathing classifier in the last chapter.

Download or read book A Study of Respiratory Motion Artifacts in Magnetic Resonance Imaging and Spectroscopy written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Motion Modelling for Respiratory Motion Estimation in Minimally Invasive Cardiac Interventions Using Intraprocedure Ultrasound Data written by and published by . This book was released on 2014 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results show an average value for the 50th and 95th quantiles of the estimation error of 1.6mm and 4. 7mm respectively, without the need for a subject-specific dynamic calibration scan. Finally, the above mentioned parts were combined to produce a personalised Bayesian motion model. The technique is accurate and does not significantly complicate the clinical workflow, thus making it suitable for clinical uptake.

Download or read book The EACVI Textbook of Cardiovascular Magnetic Resonance written by Victor Ferrari and published by Oxford University Press. This book was released on 2018-09-13 with total page 673 pages. Available in PDF, EPUB and Kindle. Book excerpt: This highly comprehensive and informed textbook has been prepared by the Cardiovascular Magnetic Resonance section of the European Society of Cardiology association on imaging, the EACVI. The EACVI Textbook of Cardiovascular Magnetic Resonance is the authority on the subject. The textbook is aligned with ESC Core Curriculum and EACVI Core Syllabus for CMR. It is a practical resource and provides a disease orientated outlook on the subject. Structured with thirteen clear and detailed sections, ranging from Physics to Methodology, and featuring specific sections on ischemic heart disease, myocardial disease, pericardial disease, and congenital heart disease and adult congenital heart disease, The EACVI Textbook of Cardiovascular Magnetic Resonance provides extensive knowledge across the entire subject area in CMR. Beautifully illustrated and physical principles enriched with schematic animations, the textbook is advanced further with key video content based on clinical cases. Written by leading experts in the field from across the world, the textbook aims to summarise the existing research and clinical evidence for the various CMR indications and provide an invaluable resource for cardiologists and radiologists across the board. The textbook is ideal for cardiologists and radiologists new to the field of Cardiovascular Magnetic Resonance, those preparing for ESC certification in CMR, and those established in the field wishing to gain a deep understanding of CMR. Online access to the digital version is included with purchase of the print book, with accompanying videos referenced within the text available on Oxford Medicine Online.

Download or read book Novel PET Radiotracers with Potential Clinical Applications An Issue of PET Clinics written by Neil Vasdev and published by Elsevier Health Sciences. This book was released on 2017-06-08 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of PET Clinics focuses on Radiotracers, and is edited by Drs. Neil Vasdev and Abass Alavi. Articles will include: PET/CT detection of HER2-positive metastases in patients with 89Zr-DFO-trastuzumab; uPAR-PET with 68Ga-NOTA-AE105: first clinical experience with a novel PET ligand; 64Cu-FBP8: A fibrin-targeted probe for imaging of thrombus; Imaging of synaptic density in the brain via synaptic vesicle glycoprotein 2A (SV2A) with a novel biomarker [11C]UCB-J; Neuroimaging of stress sensitive and neuroinflammatory targets in mood disorders; Impact of MR-based PET motion correction on the quantification of PET kinetic parameters in simultaneous cardiac PET-MR; Multimodal studies of the contributions of amyloid and tau burden to neurodegeneration in AD, FTD and Non-AD tauopathies; Imaging of prostate-specific membrane antigen (PSMA) using [18F]DCFPyL; Ga-68 GRPR antagonist imaging; and more!

Download or read book Motion Estimation Methods for Respiratory Gated SPECT written by and published by . This book was released on 2014 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Resonance Imaging for Radiation Therapy written by Ning Wen and published by Frontiers Media SA. This book was released on 2020-06-04 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Extraction and Modelling of Respiratory Motion from Four Dimensional Medical Image Data written by Tobias Klinder and published by . This book was released on 2010 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Respiratory Motion Modeling for Use in Diagnostic Imaging and Radiation Therapy written by Hadi Fayad and published by . This book was released on 2011 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important parameters reducing the sensitivity and specificity in the thoracic and abdominal areas is respiratory motion and associated deformations which represent today an important challenge in medical imaging. In addition, respiratory motion reduces accuracy in image fusion from combined positron emission tomography computed tomography (PET/CT) systems. Solutions presented to date include respiratory synchronized PET and CT acquisitions. However, differences between acquired 4D PET and corresponding CT image series have been reported due to differences in respiration conditions during PET and CT acquisitions. In addition, the radiation dose burden resulting from a 4D CT acquisition may not be justifiable for every patient. The first objective of this thesis was to generate dynamic CT images from one reference CT image; based on deformation matrices obtained from the elastic registration of 4D non attenuation corrected PET images. Such an approach eliminates, on one hand the need for the acquisition of dynamic CT, while at the same time ensuring the good matching between CT and PET images. The second objective was to develop and evaluate methods of building patient specific respiratory motion models and at as a second step more developed generic respiratory motion models. These models relate the internal motion to the parameters of an external surrogate signal (PET respiratory signal or patient's surface) that can be acquired during data acquisition and treatment delivery. Finally, the two developed models were validated and used in the PET respiratory motion and attenuation correction and in radiation therapy applications.

Download or read book Lung Motion Model Validation Experiments Free Breathing Tissue Densitometry and Ventilation Mapping Using Fast Helical CT Imaging written by Tai H. Dou and published by . This book was released on 2016 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan geometries, employed as ground truth data. Image similarity between the simulated and ground truth scans was evaluated. The model validation experiments were conducted in a patient cohort of seventeen patients to assess the model robustness and inter-patient variation. The model error averaged over multiple tracked positions from several breathing cycles was found to be on the order of one millimeter. In modeling the density change under free breathing condition, the determinant of Jacobian matrix from the registration-derived deformation vector field yielded volume change information of the lung tissues. Correlation of the Jacobian values to the corresponding voxel Housfield units (HU) reveals that the density variation for the majority of lung tissues can be very well described by mass conservation relationship. Different tissue types were identified and separately modeled. Large trials of validation experiments were performed. The averaged deviation between the modeled and the reference lung density was 30 HU, which was estimated to be the background CT noise level. In characterizing the lung ventilation function, a novel method was developed to determine the extent of lung tissue volume change. Information on volume change was derived from the deformable image registration of the fast helical CT images in terms of Jacobian values with respect to a reference image. Assuming the multiple volume change measurements are independently and identically distributed, statistical formulation was derived to model ventilation distribution of each lung voxels and empirical minimum and maximum probability distribution of the Jacobian values was computed. Ventilation characteristic was evaluated as the difference of the expectation value from these extremal distributions. The resulting ventilation map was compared with an independently obtained ventilation image derived directly from the lung intensities and good correlation was found using statistical test. In addition, dynamic ventilation characterization was investigated by estimating the voxel-specific ventilation distribution. Ventilation maps were generated at different percentile levels using the tissue volume expansion metrics.

Download or read book Computational Methods of Modeling Vascular Geometry and Tracking Pulmonary Motion from Medical Images written by Guanglei Xiong and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern anatomical medical imaging technologies, such as computed tomography and magnetic resonance, capture structures of the human body in exquisite detail. Computational anatomy is a developing discipline to extract and characterize the anatomy from images. Unfortunately, anatomical images do not reveal the functional behavior. Computational physiology shows great potential to link the structure-function relationship by considering both the anatomical information and the physical governing laws. The simulated physiology can be used to assess physiological states, and more importantly predict the outcomes of interventions. On the other hand, advances in the functional imaging techniques provide measured physiology information and should be utilized together with computational physiology. In the theme of computational anatomy and physiology, this dissertation describes computational methods of modeling vascular geometry for image-based blood flow computation and tracking pulmonary motion for image-guided radiation therapy. Blood flow computation is a useful tool to quantify in vivo hemodynamics. The essential first step is to model vascular geometry from medical imaging data. I have developed a new workflow for this task. The geometric model construction is based on 3D image segmentation and geometric processing. To represent the topology of the constructed model, I have developed a novel centerline extraction method. To account for compliant vessels, methods to assign spatially-varying mechanical properties of the vessel wall are also developed. The workflow greatly increases the modeling efficiency. The combination of the patient-specific geometry and wall deformation can enhance the fidelity of blood flow simulation. Image-based blood flow computation also holds great promise for device design and surgical procedure evaluation. Next, I have developed novel virtual intervention methods to deploy stents or stent grafts to patient-specific pre-operative geometric models constructed from medical images. These methods enable prospective model construction and may be used to evaluate the outcomes of alternative treatment options. Respiratory motion is closely related to the physiology of the lung. Finally, I have developed a novel framework to track patient-specific pulmonary motion from 4D computed tomography images. A large set of vascular junction structures in the lung are identified as landmarks and tracked to obtain their motion trajectories. This framework can provide accurate motion information, which is important in radiation therapy to reduce healthy tissue irradiation while allowing target dose escalation. This work demonstrates the importance of the geometry and motion modeling tools in computational anatomy and physiology. Accurate physiological information, whether simulated or measured, will benefit the diagnosis and treatment of various diseases.

Download or read book Cardiovascular Magnetic Resonance Imaging written by Raymond Y. Kwong and published by Springer. This book was released on 2019-01-31 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: The significantly updated second edition of this important work provides an up-to-date and comprehensive overview of cardiovascular magnetic resonance imaging (CMR), a rapidly evolving tool for diagnosis and intervention of cardiovascular disease. New and updated chapters focus on recent applications of CMR such as electrophysiological ablative treatment of arrhythmias, targeted molecular MRI, and T1 mapping methods. The book presents a state-of-the-art compilation of expert contributions to the field, each examining normal and pathologic anatomy of the cardiovascular system as assessed by magnetic resonance imaging. Functional techniques such as myocardial perfusion imaging and assessment of flow velocity are emphasized, along with the exciting areas of artherosclerosis plaque imaging and targeted MRI. This cutting-edge volume represents a multi-disciplinary approach to the field, with contributions from experts in cardiology, radiology, physics, engineering, physiology and biochemistry, and offers new directions in noninvasive imaging. The Second Edition of Cardiovascular Magnetic Resonance Imaging is an essential resource for cardiologists and radiologists striving to lead the way into the future of this important field.

Download or read book A Study of Respiratory Motion Artifacts in Magnetic Resonance Imaging and Spectroscopy written by Theodoros N. Arvanitis and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Respiratory Motion Artifacts in Magnetic Resonance Imaging written by Michael L. Wood and published by . This book was released on 1986 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Motion Correction in MR written by Andre van der Kouwe and published by Academic Press. This book was released on 2022-10-28 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: Motion Correction in MR: Correction of Position, Motion, and Dynamic Changes, Volume Eight provides a comprehensive survey of the state-of-the-art in motion detection and correction in magnetic resonance imaging and magnetic resonance spectroscopy. The book describes the problem of correctly and consistently identifying and positioning the organ of interest and tracking it throughout the scan. The basic principles of how image artefacts arise because of position changes during scanning are described, along with retrospective and prospective techniques for eliminating these artefacts, including classical approaches and methods using machine learning. Internal navigator-based approaches as well as external systems for estimating motion are also presented, along with practical applications in each organ system and each MR modality covered. This book provides a technical basis for physicists and engineers to develop motion correction methods, giving guidance to technologists and radiologists for incorporating these methods in patient examinations. Provides approaches for correcting scans prospectively and retrospectively Shows how motion and secondary effects such as field changes manifest in MR scans as artifacts and subtle biases in quantitative research Gives methods for measuring motion and associated field changes, quantifying motion and judging the accuracy of the motion and field estimates