Fast T1 mapping with volume coverage

Abstract

Four different sequences which enable high-resolution, multislice T1 relaxation-time mapping are presented. All these sequences are based on the Look-Locker method with differences arising from the use of either a saturation-recovery or inversion-recovery module prior to data acquisition with a full k-space or banded k-space acquisition scheme. The methods were implemented on a standard clinical scanner and the accuracy of the T1 results was evaluated against spectroscopic measurements. The accuracy of the T1 maps validated by phantom imaging measurements is around 1% for species which relax with T1 times that mimic gray/white matter (T1 ≤ 1000 ms). Additionally, the inherent multislice, multipoint capability of the methods is demonstrated. Finally, in vivo results of the human brain obtained using the faster method are presented. The fastest data acquisition was achieved with a saturation-recovery, banded k-space method where k-space was divided into three segments; an overall acquisition time of around 5 min (for species with T1 ≤ 1 sec) was achieved for a T1 map which can, in principle, provide whole-brain coverage with a matrix size of 256 × 256 at multiple time-points. © 2001 Wiley-Liss, Inc.