文档介绍：INVESTIGACION´ REVISTA MEXICANA DE FISICA´ 50 (3) 272–286 JUNIO 2004
Principles of ic resonance imaging
. Rodr´ıguez
Centro de Inestigacion´ en Imagenolog´ıa e Instrumentacion´ Medica,´
Universidad Autonoma´ Metropolitana Iztapalapa,
Av. San Rafael Atlixco 186, Mexico,´ D. F., 09340. Mexico,´
Telephone No.: 85 02 45 69, Fax No.: (5255) 5804-4631,
e-mail: ******@
Recibido el 25 de agosto de 2003; aceptado el 8 de diciembre de 2003
The concepts of ic resonance imaging are reviewed and its application to medical and biological systems is described. The ic
resonance phenomenon can be described by both classical and quantum mechanical approaches. ic resonance imaging is based on the
techniques of nuclear ic resonance. The scanner first aligns the nuclear spins of hydrogen atoms in the patient and starts rotating them
in a perfect concert. The nuclei emit maximum-strength ic waves at the start, but over time the rotating spins get out of synch,
simply due to small differences in local ic fields. The unsynchronized spins cause bined ic signal to decay with
time, a phenomenon called relaxation. A slice is selected applying a gradient in a particular direction (X, Y or Z). ic resonance signals
are then formed by means of the application of ic field gradients along three different directions. Finally, the signals are acquired and
Fourier transformed to form a two-dimensional or three-dimensional image. Important parameters determining the image quality such as
signal-to-noise ratio, contrast and resolution are discussed too. A review of the most widely utilised imaging techniques is given including
ultra-fast sequences.
Keywords: ic resonance imaging; pulse sequences; ultra-fast imaging.
Los conceptos de la imagenolog´ıa por resonancia ica´ son revisados y se describen algunas de sus aplicaciones a sistemas biologicos´
ymedicos.´ El fenomeno´ de resonancia ica´ puede describirse tanto con un enfoque mecanico´ cuantico´ como clasico.´ El