Even the earliest applications of nuclear magnetic resonance (NMR) spectroscopy and tomography to medical inquiries, using experimental apparatus that was primitive by today's standards, demonstrated the extraordinary potential of the NMR method. The subsequent rapid advances in this area were due largely to the ef forts of commercial manufacturers, who, by improving magnet and computer designs, were able to produce and market instruments having a remarkable image quality. Experimental data from the ftrst systematic studies on the medical uses of NMR leave little doubt that NMR will gain a permanent place in clinical diagnosis. The clinician, then, is confronted with an entirely new diagnostic modality. Because NMR has been used extensively in chemistry and physics for years, a great many textbooks are already available on the subject. However, the majority of these have been written for the natural scientist who is well versed in mathematics and physics. Assumptions are made and terms are used that would not be appro priate for a medical or biochemical text. The goal of this introduc tion, therefore, is to discuss the principles of the NMR technique in terms that are meaningful to the medical student and medical pro fessional.

Inhaltsangabe1 Potential Medical Applications of the NMR Technique.- 2 Basic Principles of NMR Spectroscopy.- 2.1 The NMR Experiment.- 2.2 The Chemical Shift.- 2.3 Line Width and Relaxation.- 2.4 Acquisition of the NMR Signal.- 2.5 Design of a Whole-Body NMR System.- 3 NMR Spectroscopy in Intact Biologic Systems.- 3.1 In Vivo 1H-NMR Spectroscopy.- 3.2 In Vivo 13C-NMR Spectroscopy.- 3.3 In Vivo 31P-NMR Spectroscopy.- 4 NMR Tomography.- 4.1 Basic Principles of NMR Imaging.- 4.2 Image Reconstruction.- 4.2.1 Selecting an Image Plane.- 4.2.2 Image Reconstruction by Back Projection.- 4.2.3 Image Reconstruction by Two-dimensional Fourier Transformation.- 4.3 Measurement of Relaxation Times.- 4.3.1 Spin-Lattice Relaxation Time T1.- 4.3.2 Spin-Spin Relaxation Time T2.- 4.4 Data Acquisition Strategies in NMR Tomography.- 4.5 The NMR Tomogram.- 4.5.1 Tissue Properties Which Affect the Image.- 4.5.2 Pertinent Imaging Parameters.- 4.5.3 Effects of Flow.- 4.5.4 NMR Contrast Media.- 4.5.5 Imaging Time.- 4.5.6 NMR Tomography of Elements Other than Hydrogen.- 4.6 Examples of the First Applications of NMR Tomography.- 4.6.1 Head.- 4.6.2 Torso.- 4.7 Health Risks of NMR Tomography.- 4.7.1 Physiologic Effects of Magnetic and Radiofrequency Fields.- 4.7.2 Risks from Metallic Implants.- 4.7.3 Safety Recommendations.- 5 Outlook.- Appendix A The NMR Experiment in the Rotating Coordinate System.- Appendix B Glossary.- 6 Addendum.- 7 Subject Index.