Nuclear magnetic resonance imaging(NMRI) gained popularity among other imaging systems due its high resolution capacity and chemical specific imaging .NMRI is a non- invasive imaging technique which uses magnetic fields and radio frequency waves for imaging the body .NMR images are maps that show the distribution density of hydrogen nuclei as well as parameters that reflect their motion in cellular water and lipids .The fact that NMR is less hazardous and images can be obtained in any cross section makes it more attractive.
PRINCIPLE OF MRIMRI works based on the spin and magnetic moment possessed by protons or neutrons of our body .The response of protons(magnetic moment) when placed in an external magnetic field involving excitation of protons in presence of field and relaxation when removed produces two relaxation times T1 and T2. T1 is the spin lattice relaxation of perturbered nucleus(also called longitudinal relaxation) while T2 is the spin -spin relaxation of nucleus(also called transverse relaxation).T2 is smaller than T1 .Variations in relaxation time help in biological discrimination of tissues.
COMPONENTS OF MRI SYSYTEMThe basic components of an MRI system include The Magnet(superconducting magnet),RF transmitter system( RF transmitter, RF amplifier, RF transmitting coils),Detection system, Gradient system for spatial coding ,Patient couch.
ADVANTAGES OF MRIThis type of imaging system provides better contrast between tissues and provides different cross sectional images .Since there is no exposure to ionizing radiations it is least hazardous .With developing technology 3-D imaging using MRI becomes possible that can replace the slice by slice imaging techniques.