Fourier transform nuclear magnetic resonance tomographic imaging

Nuclear Magnetic Resonance (NMR) tomographic imaging is a newly emerging, noninvasive, three-dimensional (3-D) imaging technique. Although similar to the well known X-ray Computerized Tomography (X-CT), it uses magnetic fields and RF signals to obtain anatomical information about the human body as cross-sectional images in any desired direction, and can easily discriminate between healthy and abnormal tissues. This new technique is an interdisciplinary science which encompasses the latest technologies in electrical, electronics, computers, physics, chemistry, mathematics, and medical sciences. Principles of this new technique known as "Fourier transform nuclear magnetic resonance imaging" or simply "NMR imaging" are reviewed from the physics and engineering points of view to provide basic concepts and tools, which, hopefully, will be useful for the future development of this exciting new field. Along with the review of the basic principles and methods involved in NMR tomography, computer simulations and modelings are presented to clarify the complexity of the NMR imaging method and provide an insight into the method, especially image-formation aspects and processing, the central theme of NMR tomography. In this paper, four main types of imaging methods-namely, line-scan imaging, direct Fourier-transform (Kumar-Welti-Ernst method) imaging, line-integral projection reconstruction, and plane-integral projection reconstruction, as well as the possibility of relaxation time imaging, are discussed in detail Methods of improving performance with respect to the statistical aspects of image quality and imaging times are also discussed.