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In the fall semester of 1994, I became a new assistant professor of physics at Oakland University, in the specialization of medical physics. After receiving my assignment to teach a graduate-level one-semester course in magnetic resonance imaging (MRI) for the next semester, I sat in my nearly empty office and wondered what and how to teach my students. As someone who had been working in MRI research for eight years at that time, I knew the importance of the fundamental theory. As someone who had been a hands-dirty experimentalist, I knew the importance of hardware and software that enabled any experiment. As someone who was specialized in quantitative MRI, I loved this field of research where the final result was an image, hopefully a beautiful and useful one. At the same time, I remembered my occasional regret during my imaging career that I did not know much about spectroscopy. I therefore determined to teach my students a little bit of nuclear magnetic resonance (NMR) spectroscopy.

I started to read the books that were available at the time, to find a potential textbook for my students. I wished I had read some of these books earlier, since there was so much that I simply didn’t know! As I went over these books for a possible adaptation for my course, I could not find any single book that contained what I had in my mind as the four essential and inseparable components of MRI – theory, instrumentation, spectroscopy, and imaging. There were books that were excellent and extensive in each of the four essential components in MRI. I was, however, unable to find one book that introduces all four components that I had in mind. (Asking my students to buy multiple books for one course was not an option.) I eventually realized, painfully, that I would have to put together the materials myself, if I wanted to teach the course as I had planned in my mind. My starting point was two excellent books that were available at that time: P.T. Callaghan’s Principles of Nuclear Magnetic Resonance Microscopy (Oxford University Press, 1991) and R.K. Harris’s Nuclear Magnetic Resonance Spectroscopy (Longman Scientific & Technical, 1989). I had the pleasure to communicate with both authors on their books during my teaching. My lecture notes, evolved and revised substantially during the last 26 years, became the basis for this book.

Since my course is for one 14-week semester, I must pick and choose what I could cover within that given time; I simply do not have time to cover all important concepts in all four components in great detail. I, however, determined to cover all four components of MRI: the theory of physics that explains this fascinating phenomenon, the instrumentation and experimental techniques that facilitate the execution of this fascinating phenomenon, the early adaptation of this physics phenomenon in the practice of NMR spectroscopy, and finally MRI. The requirements and time constraints of the course reflect the compromised (or optimized) choices, which are personal, for the topic selections in this book and the words “Essential Concepts” in the title of this book.

This book is grouped into five parts. Part I introduces the essential concepts in magnetic resonance, including the use of the classical description and a brief introduction of the quantum mechanical description. It also includes the description for a number of nuclear interactions that are fundamental to magnetic resonance. Part II covers the essential concepts in experimental magnetic resonance, which are common for both NMR spectroscopy and MRI. Part III describes the essential concepts in NMR spectroscopy, which should also be beneficial for MRI researchers. Part IV introduces the essential concepts in MRI. The final part is concerned with the quantitative and creative nature of MRI research. At the end of the book there are several short appendices, which include some background information on several topics in the book, some sample syllabi for possible ways to teach this course, as well as some homework problems.

I owe a great debt to the late Sir Paul T. Callaghan, who was my graduate advisor at Massey University in Palmerston North, New Zealand during 1986–1992. He taught me the art and science of NMR imaging at microscopy resolution (µMRI).

In my own research journey at Oakland University since 1994, I am very grateful for the beautiful works of my graduate students (Jonathan Moody, Hisham Alhadlaq, Jihyun Lee, Farid Badar, Daniel Mittelstaedt, David Kahn, Syeda Batool, Hannah Mantebea, Amanveer Singh, Austin Tetmeyer, Aaron Blanc), the mutual education of my former postdocs in MRI (ShaoKuan Zheng, Nian Wang, Rohit Mahar, Nagaraja Cholashetthalli), and the stimulating exchange of many visiting and sabbatical scientists to my lab (Paul T. Callaghan, Siegfried Stapf, Hisham A. Alhadlaq, Ekrem Cicek, RanHong Xie, ZhiGuo Zhuang, Zhe Chen). I have also benefited in my MRI research from the collaboration and interactions with many professional colleagues in MRI (Eiichi Fukushima, Kenneth Jeffrey, Gregory Furman, Jia Hua, Yong Lu, Quan Jiang, Jiani Hu, Craig Eccles, Mark Mattingly, Dieter Gross, Thomas Oerther, Volker Lehmann). Thank you.

I am grateful for four five-year R01 grants from the National Institutes of Health (NIH NIAMS) to my research lab at Oakland University, much internal support from the Research Excellence Fund in Biotechnology and the Center for Biomedical Research at Oakland University, the Department of Physics at Oakland University, and an NMR instrument endorsement from R.B. and J.N. Bennett (Oakland University), which initiated and supported my micro-imaging adventure at Oakland University.

My special thanks go to several colleagues who contributed directly to this book: Bradley J. Roth (Oakland University) and Siegfried Stapf (Technische Universität Ilmenau), who generously offered to read and comment on a draft of this book; Dylan Twardy (Oakland University), who worked with me during a previous semester to obtain some NMR spectra that are used in the book and also read the spectroscopy chapters; Roman Dembinski (Oakland University), who read the spectroscopy chapters in this book; and Farid Badar (Oakland University), who provided several image examples used in the book. I also thank the students in my classes over the years (in particular, several students in my most recent class, who had the opportunity to use an early version of the typed notes); all of you have made this book better.

My final thanks go to my sister, Xing, my daughter, Aimee, and son, Derek – you have successfully kept the homebound me during the 2020 pandemic sane and productive. You see, I had dreamed about publishing my lecture notes as a book for some 15 years. I started on this journey several times in the past, and each time I dropped it without completion due to the onset of a few work-/family-related tasks. Yes, these were excuses, I know! When this pandemic started in the beginning of 2020, I had to prepare to teach this course online. After I transcribed the mostly handwritten notes onto a home computer, I kept revising it using the lockdown months when I was working from home. So, here it is.

To my readers, I would love to hear from you, for any corrections and suggestions you might have.

Yang Xia

Distinguished Professor

Professor of Physics

Fellow of the American Physical Society (APS)

Fellow of the International Society for Magnetic Resonance in Medicine (ISMRM)

Fellow of the American Institute for Medical and Biological Engineering (AIMBE)Fellow of the Orthopaedic Research Society (ORS)

Department of Physics

Oakland University

Rochester, Michigan, USA

xia@oakland.edu

micromri@gmail.com

The first draft 2020.8.2

The second draft 2021.1.20

The final revision 2021.3.31