CONTRAST AND RESOLUTION CONSIDERATIONS IN KEYHOLE MRI - APPLICATION TO DYNAMIC STUDIES OF CONTRAST-MEDIA KINETICS

This report presents a quantitative evaluation of the effect of the ke yhole technique on contrast-enhanced dynamic MRI; specifically, the ef fect of the observed region of interest (ROI) on keyhole images was ev aluated in comparison with a complete set of data. The limiting condit ion of the quantitative use of the keyhole approach was defined and ex emplified. Results obtained by simulations, as well as on MR images, i ndicated that object size and noise level determine the minimum keyhol e size and maximum size of the ROI, so that if keyhole parameters are properly selected, a quantitative analysis of MRI gives the same signa l intensity as complete data acquisition. In this case the time resolu tion increases by factor N/L.