254. Fast T1,T2, M0 mapping in clinical MRI: Look-locker based inversion recovery balanced turbo field echo

Abstract

Purpose T1, T2 maps in MRI allows to evaluate quantitatively the state of organs and to recognize anomalies. Look-Locker based Inversion Recovery Balanced Turbo Field Echo (LL-IR-BTFE) is a distortion free sequence that hold high SNR allowing fast mapping in every region of the body, in particular myocardial tissue, liver and brain. This study investigated a method to achieve fast T1, T2, M0 maps of phantoms and their accuracy. Methods The Philips MRI phantom has been used centred in the head coil of the Philips scanner Ingenia 3T. After local shimming, the scans have been performed using conventional spin echo pulse sequences to find the real T1 and T2. Next the phantoms have been scanned using the LL-IR- BTFE. We recovered an estimation of T1, T2 and M0 (in arbitrary units) using 3 parameter fit and correction expressions [1] , next we compared the maps obtained increasing flip angles and profile corrections [2] . Results The images were free of distortion but the susceptibility artifact was found, the percentage difference between the T1 in a central ROI using IR-BTFE and spin echo is less than 8% for the scans at different flip angles in the full T1 range after profile correction. The standard deviation was around 1.2% of T1 and T2; the values are reproducible in identical scans with percent differences of 1.3%. Conclusions The process needs an accurate choice of parameters to maximize the accuracy in maps and the range of T1,T2 involved must be known in advance in order to find the best flip angle.