Description of images based on the absorption of x-rays is passé 

Quantitative MRI of the Brain, edited by Paul Tofts. Published by Wiley, price £175.00.    Reviewed by Professor V R McCready, Consultant Radiologist at the Royal Marsden Hospital, Sutton, Surry.    One of the first books devoted to the use of magnetic resonance for functional studies was published in 1987 and had a mere 205 pages. In 2003, this new book limited to functional studies(*) of only the brain has 633 pages.    It is an excellent multi-authored review of the physics,  principles, clinical and potential clinical applications of magnetic resonance imaging and spectroscopy in the brain.    The book is divided into sections discussing the measurement process, MR parameters, biology, the analysis of MR images and speculation on the future of these techniques in the study of the brain.     It would seem that, when considering the future of radiology, the days of being satisfied with descriptions of images based on the absorption of x-rays are passé.    "The pre-eminent role of imaging now requires a new level of metric-quantitative measurements." Thus the book has a heavy emphasis on mathematics, graphs and equations.

As one would expect, there is in-depth analysis of the MR parameters of proton density, longitudinal and transverse relaxation times, and water diffusion. The measurement process is analysed in detail.    Spectroscopy techniques for the measurement of proton metabolite concentrations are discussed and beautifully illustrated. The use of contrast agents is explained, with their use in the measurement of cerebral blood flow, cerebral blood volume and mean transit time.        There are many examples of clinical applications of MR and MRS measurements in the various disease states of the brain. In many areas the techniques have yet to make their way into clinical practice but the high resolution and unique data available from MR offer very exciting possibilities.    A particularly fascinating application is fibre tractography where the fibre tracts in white matter can be traced, for example, in relation to neoplasms.    This book is a valuable addition to radiological reference libraries. It certainly gives an indication of the future direction of radiology where measurement and a deeper knowledge of the physical parameters behind the images will be required.

                        (*) In fact all the major MRI techniques are described, not just functional MRI.