Quantitative Magnetic Resonance Imaging is a ‘go-to’ reference for methods and applications of quantitative magnetic resonance imaging, with specific sections on Relaxometry, Perfusion, and Diffusion. Each section will start with an explanation of the basic techniques for mapping the tissue property in question, including a description of the challenges that arise when using these basic approaches. For properties which can be measured in multiple ways, each of these basic methods will be described in separate chapters. Following the basics, a chapter in each section presents more advanced and recently proposed techniques for quantitative tissue property mapping, with a concluding chapter on clinical applications. The reader will learn: The basic physics behind tissue property mapping How to implement basic pulse sequences for the quantitative measurement of tissue properties The strengths and limitations to the basic and more rapid methods for mapping the magnetic relaxation properties T1, T2, and T2* The pros and cons for different approaches to mapping perfusion The methods of Diffusion-weighted imaging and how this approach can be used to generate diffusion tensor maps and more complex representations of diffusion How flow, magneto-electric tissue property, fat fraction, exchange, elastography, and temperature mapping are performed How fast imaging approaches including parallel imaging, compressed sensing, and Magnetic Resonance Fingerprinting can be used to accelerate or improve tissue property mapping schemes How tissue property mapping is used clinically in different organs Structured to cater for MRI researchers and graduate students with a wide variety of backgrounds Explains basic methods for quantitatively measuring tissue properties with MRI - including T1, T2, perfusion, diffusion, fat and iron fraction, elastography, flow, susceptibility - enabling the implementation of pulse sequences to perform measurements Shows the limitations of the techniques and explains the challenges to the clinical adoption of these traditional methods, presenting the latest research in rapid quantitative imaging which has the possibility to tackle these challenges Each section contains a chapter explaining the basics of novel ideas for quantitative mapping, such as compressed sensing and Magnetic Resonance Fingerprinting-based approaches
Among medical imaging modalities, magnetic resonance imaging (MRI) stands out for its excellent soft-tissue contrast, anatomical detail, and high sensitivity for disease detection. However, as proven by the continuous and vast effort to develop new MRI techniques, limitations and open challenges remain. The primary source of contrast in MRI images are the various relaxation parameters associated with the nuclear magnetic resonance (NMR) phenomena upon which MRI is based. Although it is possible to quantify these relaxation parameters (qMRI) they are rarely used in the clinic, and radiological interpretation of images is primarily based upon images that are relaxation time weighted. The clinical adoption of qMRI is mainly limited by the long acquisition times required to quantify each relaxation parameter as well as questions around their accuracy and reliability. More specifically, the main limitations of qMRI methods have been the difficulty in dealing with the high inter-parameter correlations and a high sensitivity to MRI system imperfections. Recently, new methods for rapid qMRI have been proposed. The multi-parametric models at the heart of these techniques have the main advantage of accounting for the correlations between the parameters of interest as well as system imperfections. This holistic view on the MR signal makes it possible to regress many individual parameters at once, potentially with a higher accuracy. Novel, accurate techniques promise a fast estimation of relevant MRI quantities, including but not limited to longitudinal (T1) and transverse (T2) relaxation times. Among these emerging methods, MR Fingerprinting (MRF), synthetic MR (syMRI or MAGIC), and T1‒T2 Shuffling are making their way into the clinical world at a very fast pace. However, the main underlying assumptions and algorithms used are sometimes different from those found in the conventional MRI literature, and can be elusive at times. In this book, we take the opportunity to study and describe the main assumptions, theoretical background, and methods that are the basis of these emerging techniques. Quantitative transient state imaging provides an incredible, transformative opportunity for MRI. There is huge potential to further extend the physics, in conjunction with the underlying physiology, toward a better theoretical description of the underlying models, their application, and evaluation to improve the assessment of disease and treatment efficacy.
qMRI is a rapidly evolving scientific field of high current interest because it has the potential of radically changing the clinical and research practices of magnetic resonance imaging (MRI). This focuses solely on the theoretical aspects of qMRI, which are treated and analyzed at three different spatial scales, specifically: i) the quantum physics scale of individual spins; ii) the semi-classical physics scale of spin packets; and iii) the imaging scale of voxels. Topics are presented paying particular attention to theoretical unification and mathematical uniformity.
Quantitative MRI of the Spinal Cord is the first book focused on quantitative MRI techniques with specific application to the human spinal cord. This work includes coverage of diffusion-weighted imaging, magnetization transfer imaging, relaxometry, functional MRI, and spectroscopy. Although these methods have been successfully used in the brain for the past 20 years, their application in the spinal cord remains problematic due to important acquisition challenges (such as small cross-sectional size, motion, and susceptibility artifacts). To date, there is no consensus on how to apply these techniques; this book reviews and synthesizes state-of-the-art methods so users can successfully apply them to the spinal cord. Quantitative MRI of the Spinal Cord introduces the theory behind each quantitative technique, reviews each theory’s applications in the human spinal cord and describes its pros and cons, and suggests a simple protocol for applying each quantitative technique to the spinal cord. Chapters authored by international experts in the field of MRI of the spinal cord Contains “cooking recipes —examples of imaging parameters for each quantitative technique—designed to aid researchers and clinicians in using them in practice Ideal for clinical settings
|Author||: Laurence James Abernethy|
|Release Date||: 2004|
|Pages||: 329 pages|
|Author||: Efthyvoulos Kyriacou,Stelios Christofides,Constantinos S. Pattichis|
|Release Date||: 2016-03-31|
|ISBN 10||: 3319327038|
|Pages||: 1367 pages|
This volume presents the proceedings of Medicon 2016, held in Paphos, Cyprus. Medicon 2016 is the XIV in the series of regional meetings of the International Federation of Medical and Biological Engineering (IFMBE) in the Mediterranean. The goal of Medicon 2016 is to provide updated information on the state of the art on Medical and Biological Engineering and Computing under the main theme “Systems Medicine for the Delivery of Better Healthcare Services”. Medical and Biological Engineering and Computing cover complementary disciplines that hold great promise for the advancement of research and development in complex medical and biological systems. Research and development in these areas are impacting the science and technology by advancing fundamental concepts in translational medicine, by helping us understand human physiology and function at multiple levels, by improving tools and techniques for the detection, prevention and treatment of disease. Medicon 2016 provides a common platform for the cross fertilization of ideas, and to help shape knowledge and scientific achievements by bridging complementary disciplines into an interactive and attractive forum under the special theme of the conference that is Systems Medicine for the Delivery of Better Healthcare Services. The programme consists of some 290 invited and submitted papers on new developments around the Conference theme, presented in 3 plenary sessions, 29 parallel scientific sessions and 12 special sessions.
Propelling quantitative MRI techniques from bench to bedside, Quantitative MRI in Cancer presents a range of quantitative MRI methods for assessing tumor biology. It includes biophysical and theoretical explanations of the most relevant MRI techniques as well as examples of these techniques in cancer applications. The introductory part of the book covers basic cancer biology, theoretical aspects of NMR/MRI physics, and the hardware required to form MR images. Forming the core of the book, the next three parts illustrate how to characterize tissue properties with endogenous and exogenous contrast mechanisms and discuss common image processing techniques relevant for cancer. The final part explores emerging areas of MR cancer characterization, including radiation therapy planning, cellular and molecular imaging, pH imaging, and hyperpolarized MR. Each of the post-introductory chapters describes the salient qualitative and quantitative aspects of the techniques before proceeding to preclinical and clinical applications. Each chapter also contains references for further study. Leading the way toward more personalized medicine, this text brings together existing and emerging quantitative MRI techniques for assessing cancer. It provides a self-contained overview of the theoretical and experimental essentials and state of the art in cancer MRI.
|Author||: Codi Amir Gharagouzloo|
|Release Date||: 2016|
|Pages||: 85 pages|
The ability to measure structural and functional features of health and disease is limited by our current clinical imaging toolbox. For angiography, approximately 1-5 million people in the U.S. are not candidates for contrast-enhanced magnetic resonance angiography (CE-MRA) because of renal malfunction. For cancer, it is difficult to predict the extent the enhanced permeability and retention (EPR) effect will be present leading to drug accumulation in tumors. Ferumoxytol has previously been used as a surrogate to assess nanoparticle accumulation, but negative contrast suffers from poor discrimination of nanoparticle localization. For neuroimaging, MRI is a powerful technique for probing the deep brain but can only provide semi-quantitative information. Cerebral blood volume (CBV) is an important indicator of tissue health and function, however current techniques are 15-30% inaccurate, and only the relative CBV is typically measured to assess function. Currently, only nuclear medicine provides an effective means of absolute quantification of contrast agent induced signal. However, the radioisotopes involved in these procedures are hazardous, and thus the use of nuclear medicine is not warranted for repeat structural and functional imaging. Here we demonstrate a novel technique that can produce CE-MRAs using magnetic nanoparticles including the FDA approved super paramagnetic iron-oxide nanoparticle (SPION) ferumoxytol with very high Contrast to Noise Ratio (CNR) in cardiovascular, cerebral, and tumor imaging in mice and rats. First, the technique is established and shown to measure clinically relevant concentrations of ferumoxytol with high fidelity range in mice. Next, a unique feature of the methodology to produce high-contrast images of purely T1-weighted signal is employed to unambiguously delineate nanoparticle accumulation in a PC3 subcutaneous tumor model with ferumoxytol accumulation 24 hours after just one dose. From this, contrast efficiency was produced compared to standard techniques with the additional benefit that pre-contrast images are not necessitated. Finally, we show unprecedented accuracy in measuring the CBV in absolute terms throughout the whole rat brain. We create a quantitative blood volume atlas and demonstrate that absolute functional measurements of CBV can be assessed by comparing the awake, CO2-challenged and anesthetized states. The method is anchored in theory and is compatible with existing clinical SPION formulations and scanners. Thus QUTE-CE shows high potential for quantitative imaging immediately applicable to human scans.
|Author||: Jianmin Yuan|
|Release Date||: 2017|
|Pages||: 329 pages|
|Author||: Byeong-Yeul Lee|
|Release Date||: 2010|
|Pages||: 264 pages|
|Author||: Xiaoke Wang|
|Release Date||: 2019|
|Pages||: 136 pages|
Non-alcoholic fatty liver disease (NAFLD) is a common liver disorder hallmarked by abnormal deposition of fat, i.e.: hepatic steatosis. NAFLD can take the form of non-alcoholic steatohepatitis (NASH) or isolated steatosis. Both forms of NAFLD can cause chronic liver injuries which leads to the progression into liver fibrosis. At the same time, NAFLD is a known risk factor of type-II diabetes and premature cardiovascular diseases. Although liver fibrosis is less common than NAFLD, it has serious complications such as liver failure. Cirrhosis as a form of advanced fibrosis is a risk factor of hepatocellular carcinoma. Effective treatments are emerging for NAFLD and liver fibrosis. Lifestyle intervention has been demonstrated to reduce hepatic steatosis and inflammation. In the case of viral hepatitis, treatment for hepatitis C virus infection often leads to the reversal of liver fibrosis (even in patients with cirrhosis). The accurate evaluation of hepatic steatosis and fibrosis using non-invasive magnetic resonance imaging (MRI) methods are needed to improve the diagnosis and treatment monitoring of patients afflicted by these conditions. Chemical shift encoded (CSE)-MRI has been established as a quantitative imaging biomarker (QIB) for hepatic steatosis. In this dissertation, the effect of non-standardized spectral model of fat was evaluated such that meaningful comparisons can be made between results obtained at different research and clinical sites. A T[subscript 1]-corrected variable flip angle (VFA) CSE-MRI was also proposed and rigorously evaluated for fat quantification in the hope of improving the precision of CSE-MRI fat quantification. Quantitative diffusion MRI using an intra-voxel incoherent motion (IVIM) model and T[subscript 2] mapping have shown promise for the evaluation of liver fibrosis. However, some additional development and validation is required for them to be recognized as QIBs. In this dissertation, a novel acetone-based diffusion phantom was proposed to provide a controlled environment for the development of quantitative diffusion MRI techniques. Further, to enable the quantification of T[subscript 2] from the water signal (parenchyma) and simultaneous quantification of R[subscript 2]*, a novel phase-based T[subscript 2] mapping technique was developed with its feasibility in the liver demonstrated.