| 摘要 |
PURPOSE: To quickly decide spin density and a relaxation time constant in the transverse direction by generating relative asymmetry of a sampled spin resonance signal caused by relaxation of horizontal direction of an excited spin which generates a spin echo signal. CONSTITUTION: It is used a fact that the spin resonance signal receives effect of relaxation of time constant T2 in the transverse direction. First, an absolute signal value is proportional to exp(-TE/T2). Secondary, the sample spin resonance signal becomes asymmetrical because of the relaxation time constant T2 of the horizontal direction. Sufficient information is made to be extracted for decision of an image of the spin densityρ(x, y, z) from the asymmetry and at the same time sufficient information to decide the image in the transverse direction relaxation time constant T2 (x, y, z) is made to be extracted from the same MRI measurement. The spin densityρ(x, y, z) can be determined very accurately from a real part of the result of Fourier transformation of the spin resonance signal obtained in a sampling interval and at the same time the very accurate measurement value of the relaxation time constant T2(x,y,z) in the transverse direction can be obtained.
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