Contrast and Resolution Consider- Ations in Keyhole Mri: Application to Dynamic Studies of Contrast Media Kinetics

Absctract This paper presents a quantitative evaluation of the effect of the keyhole technique on contrast-enhanced dynamic MRI; specifically, the effect of the observed region of interest on keyhole images compared to a complete set of data was evaluated. The limiting condition of the quantitative use of the keyhole approach was defined and exemplified. Results obtained by simulations, as well on MR Images, indicate that object size and noise-level determine the minimum keyhole size and the maximum size of the region of interest, so that if keyhole parameters are properly selected, a quantitative analysis of MRI gives the same signal intensity as complete data acquisition. In this case the time resolution increases by factor N/L.