Clinical MR neuroimaging : diffusion, perfusion, and spectroscopy

Magnetic resonance (MR) physiologic and functional techniques, which augment imaging, can now be performed during most clinical MR imaging examinations. This book’s aim is to present appropriate clinical applications of and to discuss interpretation of results from diffusion imaging, perfusion imaging, and spectroscopy. The editors have attempted to provide a reference for clinical practice with broad applications of functional imaging. The editors are longtime researchers in MR imaging. Gillard and Waldman are neuroradiologists and Barker is an imaging scientist. They have assembled an expert international team of chapter authors. An insightful introduction is provided by R. Nick Bryan, a well-known neuroradiologist experienced with physiologic and functional MR imaging. There are 46 chapters within seven clinical disease sections: cerebrovascular, neoplastic, infection/ inflammatory, epilepsy, neurodegenerative/psychiatric, trauma, and pediatric disorders. There is a six-page list of abbreviations. The abbreviation rCBF, which for decades had been defined as regional cerebral blood flow, has been defined in recent journal articles and now in this book as relative cerebral blood flow, unaccompanied by any explanation of the change of established nomenclature. The term cerebral blood flow (CBF) is subsequently defined separately. Chapter 7 presents deconvolution formulas to calculate CBF values. However, a reader not already familiar with the formulas will not know if they produce true relative CBF values in units of milliliters of blood per 100 cm of brain tissue per minute, the most precise blood flow value. Chapter 8 contains mentions of “regional blood flow” without an explanation of whether regional CBF—or another CBF value—is meant. It is unfortunate that this definitive textbook of neuroimaging physiology does not outline these discrepancies for readers. A limitation of this text is the emphasis on the advances in MR imaging techniques without much in-depth discussion of advanced computed tomographic (CT) techniques such as CT perfusion imaging. Chapter 8 compares MR perfusion imaging with positron emission tomography (PET) and xenon CT, yet mentions nothing about CT perfusion imaging, which is considered by many to be the most efficient way to immediately measure regional CBF, CBF volume, and mean transit time (MTT). CBF volume and MTT measurements without regional CBF measurements dominate reports of clinical MR imaging. CBF volume correlates well with diffusion-weighted MR imaging defects whether done with CT perfusion or MR perfusion. MTT on its own is nonspecific; it reflects the time for blood to arrive, but it does not always reflect the adequacy of blood supply. For example, patients with proximal occlusions and excellent collateral vessels without ischemia (eg, patients with acute stroke) may have markedly delayed MTT values. Chapter 10 describes the advantages of CT perfusion imaging: It is simpler and much quicker to perform than MR perfusion imaging, and is not associated with an unfriendly magnet environment. However, it takes more skill to interpret early infarction on CT images than on diffusion-weighted MR images. Readers who prefer to learn complex new material by repetition will appreciate this book, which is organized according to diseases. Specific techniques, such as MR spectroscopy, are explained multiple times across different chapters. Various peaks on MR spectra become familiar by repetition. Commercial software that identifies various chemical peaks is currently available, which further facilitates the use of MR spectroscopy in clinical practice. Other MR techniques such as tensor imaging, spectroscopy, and functional mapping have no competition from CT. Techniques such as PET are not prevalent in clinical departments, and the future seems to lie with MR for all but time-limited situations. The physiologic and functional MR techniques described in this book are here to stay and already used in the field, beyond academic sites. The editors achieve their goal of providing detailed reference tutorials for neuroimagers to understand current uses. This book is worth the cost as a reference for those who do neuroimaging or refer patients for neuroimaging studies. Reviewed by Allan J. Fox, MD BOOK REVIEWS