Magnetic Resonance Imaging

# Preface

Rapid change in the common denominator in the field of magnetic resonance (MR). There are new acronyms describing the various pulse sequences and hardly keep track of them. There are new focal coils designed for every part of the body. Developments in scanning hardware seem to change overnight and the list of potential hazards to patients and staff grows continuously. Powerful and permanent magnets have greatly simplified site preparation. Shielded gradient design methodically reduced eddy currents and improved image quality. Parallel imaging and susceptibility artifacts have become more important. New challenges arise from temperature or at the temperature of liquid nitrogen. The ability to image three-dimensional shift and diffusion is now a century. The field of view can be reduced through the use of surface coils. Many users enjoy the experience exploring growth. Adding to the complexity are the new efforts on and commitment of health-care costs, the entry of entrepreneurs and physicists into the field of MR, and the struggle for the multi-million-dollar price tags for MRI scanners.

Basic principles in MRI are being redefined against this complex background. It was therefore decided to revise and to write new chapters on an ongoing basis. In the second edition of this book I attempt to deal with some of these problems. In the new hardware and fundamentals of medium imaging certain new subjects have also been covered. Because the MR signal is based on the behavior of the pulsing sequences and the tissue characteristics in this chapter I read to characterize the signal carefully. For these reasons I have dedicated an atlas of normal MRI anatomy defines the changes of the MR signal and to provide additional anatomic detail as an aid in reporting the images. In order to present an overview a number of fundamental MR concepts, the T₁, T₂ T₁ρ, D.M., and J images are included in the book and the images of some of the fundamental MR imaging and procurement M