Optimized and combined T1 and B1 mapping technique for fast and accurate T1 quantification in contrast‐enhanced abdominal MRI

Abstract

Fast T₁ mapping techniques are a valuable means of quantitatively assessing the distribution and dynamics of intravenously or orally applied paramagnetic contrast agents (CAs) by noninvasive imaging. In this study a fast T₁ mapping technique based on the variable flip angle (VFA) approach was optimized for accurate T₁ quantification in abdominal contrast‐enhanced (CE) MRI. Optimization methods were developed to maximize the signal‐to‐noise ratio (SNR) and ensure effective RF and gradient spoiling, as well as a steady state, for a defined T₁ range of 100–800 ms and a limited acquisition time. We corrected B₁ field inhomogeneities by performing an additional measurement using an optimized fast B₁ mapping technique. High‐precision in vitro and abdominal in vivo T₁ maps were successfully generated at a voxel size of 2.8 × 2.8 × 15 mm³ and a temporal resolution of 2.3 s per T₁ map on 1.5T and 3T MRI systems. The application of the proposed fast T₁ mapping technique in abdominal CE‐MRI enables noninvasive quantification of abdominal tissue perfusion and vascular permeability, and offers the possibility of quantitatively assessing dilution, distribution, and mixing processes of labeled solutions or drugs in the gastrointestinal tract. Magn Reson Med 57:568–576, 2007.