Preface

This is a unique book providing a contemporary snapshot of the roles that nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) play in the current understanding of the biophysics and biochemistry of articular cartilage. As a treatise on cartilage research, it is the first book of its kind. All of its chapters were written by the leading experts who are active in the field.

Cartilage research is closely intertwined with the development of NMR and its imaging counterpart, MRI. Since the invention of NMR in 1946,^1,2  magnetic resonance has evolved into a highly sophisticated experimental technique with applications to a wide range of chemical and biological systems. The first study of cartilage by means of magnetic resonance was likely published in 1955³ : it examined the NMR properties of water as well as a series of biological systems, including calf cartilage. The authors found the spin relaxation times of ¹H nuclei to be significantly shorter in cartilage than in pure water, surmising that the difference can be attributed to the composition of the tissue and the molecular state of water in it. They called for further research, concluding that “...this will give valuable information of a biologic and physical nature”. This was certainly a prescient conclusion, as NMR and relaxometry have become invaluable research tools for biomedical applications, including those related to cartilage. The fascinating background of this historical journey has been recapped recently in a journal article.⁴ 

The “Holy Grail” of cartilage magnetic resonance research is early and non-invasive diagnosis of osteoarthritis, a musculoskeletal disease that is the number one cause of disability in most developing and developed countries. Gradual degradation of articular cartilage is the hallmark of osteoarthritis. The degradation process is complex. The disease always results in the same end-stage symptom (loss of joint function), but the degradation of the tissue can have different early-stage characteristics and be either idiopathic or linked to different initiation events or risk factors, such as trauma, obesity or biomechanical instability. Although the disease has been studied extensively, an accurate diagnosis of osteoarthritis at a time when the joint is still structurally sound, remains elusive in current clinical practice. Since early lesions tend to be small and localized (both topographically and depth-wise), any early detection tool must be non-invasive, sensitive to molecular-level changes in the tissue and possess spatial resolution of the order of hundreds of micrometers or better. Molecular imaging at high resolution meets these requirements. An invaluable tool in molecular imaging is MRI, which is unique in osteoarthritis management due to its high sensitivity to molecular activities and the molecular environment, and its non-invasive nature in imaging.

This book aims to provide an exposition of the two-way interaction between the fundamental science of cartilage (physics, chemistry and biology) and cartilage imaging. It also aims to capture the current state-of-the-art in imaging practice and to connect the fundamental science with the clinical applications. In doing so, the authors of this book take you on an extraordinary journey that shows how advances in the fundamental sciences have been driving (and will drive in the future) the crucial developments in NMR and MRI applications in cartilage research, and how contemporary MRI techniques have been able to provide insights into the organisation and function of cartilage.

Part one of the book introduces cartilage biology, biochemistry and biophysics, as well as NMR and MRI and the best-known effect in cartilage magnetic resonance—the magic angle effect. Part two covers the experimental NMR and MRI techniques for cartilage research. This is followed by three chapters concerned with the biomechanical aspects of cartilage investigation by NMR and MRI. The final part four deals with the applications and the future of cartilage research.

Our first and foremost thank you goes to the “dream team” of our star authors in cartilage research by NMR and MRI, who accepted our invitations and contributed collectively to this book project. We feel exceptionally privileged to have worked with this outstanding team.

We thank Prof. William S. Price, the editor-in-chief of the book series New Developments in NMR at the Royal Society of Chemistry, who initiated this project. We are also grateful to the editorial professionals at RSC, whose help and patience have made this project a lot easier.

All chapters in this book have been peer-reviewed. In addition to many contributing authors of this book who anonymously helped us to review the individual chapters and provide suggestions for improvement, we are very grateful to following expert colleagues who have critically reviewed several chapters in this book: Prof. Hartwig Peemoeller (University of Waterloo, Canada), Prof. William S. Price (Western Sydney University, Australia), Prof. John R. Matyas (University of Calgary, Canada) and Prof. Philip W. Kuchel (University of Sydney, Australia). Any errors remaining in the book are, of course, the responsibility of the editors.

Yang Xia and Konstantin Momot

Rochester, MI, USA and Brisbane, Australia