The fourth edition of Magnetic Resonance Imaging of the Brain and Spine is written at yet another critical time point in the history of clinical imaging with MRI, as we enter an unprecedented era in medical diagnosis and therapy. Imaging has come to occupy an increasingly central role in medical care. The appropriate utilization of emerging applications of molecular biology, advanced medical technologies, and minimally invasive treatments depend more than ever on delivery of the long-held promise of medical imaging. Along with the advances in medical imaging have come striking changes in demographics of populations and diseases. The world’s population is aging, and soon the elderly will dominate the health care system resources of many nations. Globalization of disease profiles is also underway; the chronic diseases of developed nations, with their reliance on imaging for diagnosis and treatment, are projected to overtake the traditionally dominating infectious and nutritional diseases of developing countries.
Early detection has become paramount, and no field will be more important in this pursuit than diagnostic imaging. I must admit that some of the trends concerning MRI are surprising, despite my own statement in the previous edition that â!oenew advances in MRI seem likely to continue at least over the next several years and beyond.â!! Almost a decade after seemingly achieving its status as a mature imaging modality by most clinical standards, MRI has maintained an accelerating path of innovation and expansion of applications. The specifics of its current clinical utilization are also somewhat unexpected, because many had anticipated that non-CNS MRI would be the most impacted over this recent period. Quite a different scenario has unfolded: brain and spine MRI has increased its dominance over other non-neurologic clinical applications, at least as judged by number of MRI procedures per year. There is no reason to expect any significant change in this trend, as higher field scanners, new methodologies, and associations with minimallyinvasive targeted therapies have already begun to be explored most often in the setting of CNS disorders. Counterintuitive to the increased utilization and clinical impact of MRI, the present era of MRI represents perhaps the most challenging yet; technology has advanced far beyond known or proven clinical applications, instrumentation is more complex than ever, and software for acquisition and image processing is just beginning to reveal its importance in clinical applications.