El escaner primero alinea los núcleos de los espines de los átomos de hidrógeno que se encuentran dentro del paciente, y luego comienza a rotarlos de acuerdo a un concierto perfecto. El fenómeno de resonancia magnética puede describirse tanto con un enfoque mecánico cuántico como clásico. Los conceptos de la imagenología por resonancia magnética son revisados y se describen algunas de sus aplicaciones a sistemas biológicos y médicos. Keywords: Magnetic resonance imaging pulse sequences ultra-fast imaging. A review of the most widely utilised imaging techniques is given including ultra-fast sequences. Important parameters determining the image quality such as signal-to-noise ratio, contrast and resolution are discussed too. Finally, the signals are acquired and Fourier transformed to form a two-dimensional or three-dimensional image. Magnetic resonance signals are then formed by means of the application of magnetic field gradients along three different directions. A slice is selected applying a gradient in a particular direction (X, Y or Z). The unsynchronized spins cause the combined electromagnetic signal to decay with time, a phenomenon called relaxation. The nuclei emit maximum-strength electromagnetic waves at the start, but over time the rotating spins get out of synch, simply due to small differences in local magnetic fields. The scanner first aligns the nuclear spins of hydrogen atoms in the patient and starts rotating them in a perfect concert. Magnetic resonance imaging is based on the techniques of nuclear magnetic resonance. The magnetic resonance phenomenon can be described by both classical and quantum mechanical approaches. The concepts of magnetic resonance imaging are reviewed and its application to medical and biological systems is described.
Centro de Investigación en Imagenología e Instrumentación Médica, Universidad Autónoma Metropolitana Iztapalapa, Av.
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