ACCURACY OF PROTON T1-CALCULATED BY APPROXIMATIONS FROM IMAGE SIGNALS

  • 1 January 1985
    • journal article
    • research article
    • Vol. 26  (1) , 54-58
Abstract
PMR imaging, T1 calculation from 2 measurements was simplified by using an approximation algorithm that assumed equilibrium recovery of longitudinal magnetizations or one that ignored refocusing 180.degree. pulses used. Errors in calculated T1 arising from either approximation were evaluated using signal expressions that presumed neither approximation. The approximation error depended on T1, sequence parameters and the simplifying algorithm. The computed relation was used to correct for the approximation error. The correction reduced calculated-T1 errors, but did not eliminate them, since other significant or potentially significant sources of the error were not accounted for. These sources related to ever-present stochasitc noises, proper signal expressions, various instrumental factors, exponential compared with nonexponential nature of tissue proton relaxation and tissue movements. The problem of quantitative T1 measurement from image signals was discussed.