Functional MRI: Basic Principles and Emerging Clinical Applications for Anesthesiology and the Neurological Sciences

Functional magnetic resonance imaging (fMRI) is an exciting tool that potentially sheds light on how the brain processes information and how disease and medications affect these processes. It is a complex melding of magnetic resonance imaging (MRI) and sophisticated mathematical and statistical processing. Functional MRI: Basic Principles and Emerging Clinical Applications for Anesthesiology and the Neurological Sciences, edited by Ramachandran Ramani, MD, Professor of Anesthesiology at the University of Florida, attempts to provide an introduction to fMRI techniques and its roles in clinical sciences. It is published by Oxford University Press and is available as a hardcover, as an EBook, or through Oxford Medicine Online. It is a multiauthored book with authors who are clinicians as well as scientists from around the world. The author states that he has used fMRI in his own research and was struck by how there was a need for a clinically relevant textbook on the subject. In addition, he felt that there was little on the basics of fMRI, making it challenging for a novice to learn about the subject. The 264-page book has a 3-chapter section on the basics of fMRI. Chapter 1, Introduction to fMRI, does a nice job of qualitatively describing the technique and some of its roles. The author describes the evolution of imaging from X-rays and computed tomography (CT) scans, which are purely imaging, to positron emission tomography (PET), MRI, and fMRI, which, in addition to providing images, provide scans describing the function of the item of interest. However, the other chapters in this section describe the methods and algorithms used in fMRI in a manner that is not detailed enough to execute the analyses on your own but in a manner that is so detailed and sophisticated that many readers may find it frustrating to work through. In this section and throughout the book, there are so many acronyms and abbreviations that the reader spends a considerable amount of time reminding himself/herself what they all mean. A glossary of abbreviations would have been helpful both to remind the reader of meanings and to ensure consistent use throughout. The next section, entitled Emerging Clinical Applications of fMRI, consists of 9 chapters describing its roles in neurosurgery and neurology, cognition, psychiatry, geriatrics, pediatrics, pain management, anesthesiology, the intensive care unit, and then finally future trends. There appears to have been little coordination among the authors with some material repeated and an inconsistent format of each chapter. The material was presented in a far more sophisticated manner than what might appeal to the novice reader. Most of the book consists of observations and very little on how to actually integrate fMRI into clinical use. An underlying theme throughout is the activation, coordination, and connectivity between different parts of the brain both in a resting state and when it is working on a specific task. In the neurology chapter, the authors discuss, for instance, how patients suffering from Alzheimer disease show decreased connectivity and how in patients with stroke the functional connectivity noted in the first week after the event has prognostic value. In the pediatric population, they describe differences in the way in which activation and coordination of brain centers in children with attention deficit/hyperactivity disorder (ADHD) differ from typical children and then interestingly how, with methylphenidate therapy, there is increased activation of cognitive control and problem-solving centers, showing a functional affirmation of the action of the medication. fMRI in studying pain shows that it is processed bilaterally and diffusely, that is, there is not a specific “pain” center. There is variability in the pain response noted on fMRI, much like there is variability in an individual’s pain response. There are not obvious “pain signatures”; however, there is work going on with artificial intelligence networks attempting to find these. Utilizing fMRI to study how anesthetic agents work is also a way to study how consciousness works. fMRI has shown dose-dependent effects of anesthetic agents; however, decreased activation or disordered coordination and connectivity among different parts of the brain appear to be different for different classes of anesthetic drugs. They provide observations on the changes noted by different anesthetic drug classes; however, putting those into context of what that means functionally is not yet available. The chapter on fMRI’s role in the intensive care unit (ICU) provides some observations in differentiating delirium from other causes of altered levels of consciousness. They also provide some interesting insights into other roles of fMRI in organ systems beyond the brain. There is probably not a role for this volume for the casual reader; however, for the practitioner wanting to integrate fMRI into his/her research protocols or practice, it does provide an introduction to this complicated field. Laurence C. Torsher, MDDepartment of Anesthesiology and Perioperative MedicineMayo ClinicRochester, Minnesota[email protected]