Reduced-encoding Dynamic Imaging

Reduced-encoding Dynamic Imaging
Author: Jill Marie Hanson
Publisher:
Total Pages: 194
Release: 1997
Genre:
ISBN:

This research addresses the problem of acquiring a time series of magnetic resonance images with both high spatial and temporal resolutions. Specifically, we systematically investigate the advantages and limitations of reduced-encoding imaging using a priori constraints. This study reveals that if the available a priori information is a reference image, direct use of this information to 'optimize' data acquisition using the existing wavelet transform or singular value decomposition schemes can undermine the capability to detect new image features. However, proper incorporation of the a priori information in the image reconstruction step can significantly reduce the resolution loss associated with reduced-encoding. For Fourier encoded data, we have shown that the Generalized-Series (GS) model is an effective mathematical framework for carrying out the constrained reconstruction step. Several techniques are proposed in this dissertation to improve the basis functions of the GS model by introducing dynamic information. The two reference reduced-encoding imaging by generalized-series reconstruction (TRIGR) method suppresses background information through the use of a second high resolution reference image. A second technique injects information from the dynamic data into the GS basis functions, as opposed to deriving them solely from the reference information. These techniques allow the GS basis functions to more accurately represent the areas of dynamic change. Finally, motion that occurs between the acquisition of the reference and dynamic data sets can render the reference information useless as a constraint for image reconstruction. A motion compensation method is proposed which uses a similarity norm to accurately detect the motion in spite of contrast changes and the low resolution nature of the dynamic data.

Cardiovascular MRI

Cardiovascular MRI
Author: Vivian S. Lee
Publisher: Lippincott Williams & Wilkins
Total Pages: 432
Release: 2006
Genre: Medical
ISBN: 9780781779968

This text equips radiologists with a firm working knowledge of the physical principles underlying cardiovascular MR image generation. Emphasis is on practical applications of MR physics in customizing and optimizing imaging sequences and protocols and minimizing artifacts. Section I covers basic principles of MR physics and includes a chapter on safety. Section II applies these principles to vascular imaging, including gadolinium-enhanced MR angiography. Section III examines various techniques and applications of cardiac MR imaging. Each chapter includes boxed Key Concepts, Challenging Questions, and Review Questions, and many chapters include sample protocols. More than 400 drawings and scans complement the text.

Heart Mechanics

Heart Mechanics
Author: El-Sayed H. Ibrahim
Publisher: CRC Press
Total Pages: 1267
Release: 2017-09-19
Genre: Medical
ISBN: 1351645382

Based on research and clinical trials, this book details the latest research in magnetic resonance imaging (MRI) tagging technology related to heart mechanics. It covers clinical applications and examines future trends, providing a guide for future uses of MRI technology for studying heart mechanics.

Parallel and Distributed Processing

Parallel and Distributed Processing
Author: José D. P. Rolim
Publisher: Springer Science & Business Media
Total Pages: 1474
Release: 1999-03-30
Genre: Computers
ISBN: 9783540658313

This book constitutes the refereed proceedings of 11 IPPS/SPDP '98 Workshops held in conjunction with the 13th International Parallel Processing Symposium and the 10th Symposium on Parallel and Distributed Processing in San Juan, Puerto Rico, USA in April 1999. The 126 revised papers presented were carefully selected from a wealth of papers submitted. The papers are organised in topical sections on biologically inspired solutions to parallel processing problems: High-Level Parallel Programming Models and Supportive Environments; Biologically Inspired Solutions to Parallel Processing; Parallel and Distributed Real-Time Systems; Run-Time Systems for Parallel Programming; Reconfigurable Architectures; Java for Parallel and Distributed Computing; Optics and Computer Science; Solving Irregularly Structured Problems in Parallel; Personal Computer Based Workstation Networks; Formal Methods for Parallel Programming; Embedded HPC Systems and Applications.

Motion Correction in MR

Motion Correction in MR
Author: Andre van der Kouwe
Publisher: Academic Press
Total Pages: 622
Release: 2022-10-28
Genre: Technology & Engineering
ISBN: 012824478X

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