We chatted to Nicole Seiberlich and Vikas Gulani about the rationale and scope of their new book Quantitative Magnetic Resonance Imaging.

What motivated you to develop a book on Quantitative MRI?

Magnetic Resonance Imaging (MRI) offers the ability to “sensitize” images to many different properties of tissue, and the myriad of exquisite contrasts available is one of the reasons MRI has been so valuable in clinical practice. However, these tissue properties are rarely measured quantitatively, though it has been hypothesized for decades (since the start of MRI) that if we could quickly, accurately, and reproducibly measure these properties, these measurements could provide great benefit in objective and uniform diagnosis and follow-up of disease. In practice, Quantitative MRI approaches have not been routinely used because of many inherent limitations of MRI, such as speed. However, recent advances in computing power, MR hardware, and image reconstruction have reinvigorated the field and the last few years have brought a proliferation of quantitative approaches, in diverse applications. With so many emerging techniques and the increasing use of Quantitative MRI in clinical settings, the time seemed right for such a book. We sought to describe the original and gold-standard methods for measuring MRI-accessible tissue properties, as well as many of the newer methods so that the book could serve as a standalone reference. Moreover, we wanted to ensure that this book would discuss not only the technical aspects of Quantitative MRI, but also the biological relevance of the tissue properties that are often measured with MRI and a discussion of how these quantitative metrics are or could be used in clinical practice, and finally some of the barriers the field still faces. By discussing multiple quantitative approaches in one book, we hope that successful similarities and also common streams of failure emerge that may help promote development of the field. In this way, we are hoping to build bridges and facilitate communication between the scientists developing Quantitative MRI techniques and physicians who use them.  

You have two introductory chapters, entitled “Quantitative MRI: Rationale and Challenges” and “MRI Biomarkers”. What is the importance of these chapters to the book?

Both of these introductory chapters are meant to set the stage for the more technical and clinical content which makes up the rest of the book, by evaluating the current state of Quantitative MRI methods in the pathway of becoming true quantitative biomarkers. The main editors (Nicole Seiberlich and Vikas Gulani) authored the first of these two chapters, entitled “Quantitative MRI: Rationale and Challenges”. This chapter explores how the availability of accurate and reproducible quantitative MRI could transform Radiology, but also describes the barriers currently in place preventing this transition to a completely quantitative exam. We present these issues from the perspective of scientists (who develop the technology) and physicians (who deploy the technology), and also attempt to provide clarity on why these methods often fail to make the transition to clinical practice. We also make some suggestions on how Quantitative MRI research could be harmonized to meet the ultimate goal of accurate and reproducible measurements of tissue properties.

The second introductory chapter, “MRI Biomarkers” authored by Hocking et al., describes the process by which a measurement becomes a recognized “biomarker,” with a focus on MRI-based measurements. We included this important chapter because while many MRI scientists are working to develop techniques for measuring tissue properties, very few think about the attributes that such a measurement must exhibit, or the process of development followed, for it to be deployed as a biomarker. By including this information, it becomes clear that we must approach Quantitative MRI in a more collaborative, and methodologically rigorous manner if we truly want these methods to be rolled out for broad use in patient care. We hope that readers will keep the information from these first two chapters in mind as they make their way through the more technical and clinically focused chapters.

How would you describe the approach and scope of the book?

This book seeks to cover both the tissue properties most commonly measured with MRI, and those that are currently seen as potentially valuable in a clinical setting. To make the book easier to tackle, we divided the book into five main sections, each of which describes a broad area of Quantitative MRI: Relaxometry, Perfusion, Diffusion, Fat/Iron Quantification, and “Other MRI-Accessible Properties.” We selected these areas because a large number of quantitative measurements fall into the first four broad categories, and many emerging technologies can be grouped together in the last section for ease of classification and understanding approach. Each section, with the exception of the last, has a similar structure. Each section starts with the biophysical and physiological relevance of the tissue properties examined in the section, which provide the motivation for measuring those properties. The next few chapters describe how these tissue properties are actually measured with MRI. Finally, the current state of clinical deployment of these quantitative MRI approaches is assessed, where examples in different patient populations are offered. In the last section, “Other MRI-Accessible Properties,” each chapter is structured like a condensed section, where the rationale, measurements, and clinical applications of the tissue property are described. We selected this structure to show the entire logical arc of tissue property measurement with MRI. After understanding the biological importance of a tissue property, we seek to measure it, and use these measurements to better assess disease.

You wanted this book to serve as a link between technical and clinical researchers in order to open up a dialogue between them. How would you advise each to use the book for when they start their dialogue?

We believe that novel Quantitative MRI techniques can only make their way to universal and robust clinical deployment through the symbiotic work of technical and clinical researchers, which is why we wrote a book for both these groups together. Appreciating complementary expertise and building mutual respect is key to such collaborations. We would advise those seeking to establish a translational collaboration to read the introductory chapters and then go through the remaining chapters of the topic of interest. However, we suggest not just reading from the perspective that the readers may themselves be comfortable with, but also those from the angle less familiar to them. In other words, we encourage technical researchers to read the applications chapters, and clinical researchers to gain an appreciation for technical challenges. While the content may not all be immediately clear, it will help provide an understanding of the current standard of work and the challenges faced by their counterparts. The information presented in the book may also serve as a starting point for discussion among collaborative teams: What are we trying to measure and why? Do we have a technology that we can use to make these measurements? What is our current practice clinically? Would any of these measurements change how we assess our patients? What barriers must we overcome to enable robust utilization?

Access complimentary introductory chapters 1 and 2:

• Quantitative MRI: Rationale and Challenges
• MRI Biomarkers

You have brought together a team of editors and authors. What decided you to bring this team together?

The field of Quantitative MRI is very broad and rapidly changing. While we wanted to include as many topics as possible, we knew that it would not be feasible to write this book without input from researchers with hands-on experience in many different areas of MRI. The project has benefited greatly from a wonderful team of Section Editors, Drs. Fernando Calamante, Adrienne Campbell-Washburn, Mariya Doneva, Houchon Harry Hu, and Steven Sourbron, who brought additional expertise and put in a lot of effort in making this book come to life. They are established experts in the subfields of Quantitative MRI that are covered in their sections. They in turn brought on the authors for the individual chapters; these authors are each world-renowned researchers specializing in the topics they write about in their chapters. By working with this team of leaders currently publishing the most cutting-edge research, we have ensured that we could bring the most up-to-date and relevant information to readers of this book.

Ready to read this book?

Quantitative Magnetic Resonance Imaging, is the first volume in a new series entitled Advances in Magnetic Resonance Technology and Applications from series editors, In-Young Choi, Brian Hargreaves, Peter Jezzard and Greg Zaharchuk. The book is available now on ScienceDirect. Or purchase your own copy on the Elsevier Bookstore and save 30% + get free shipping with promo code STC30.