Quantitative T1 mapping and absolute water content measurement using MRI

Abstract We present two methods for the mapping of the T 1 and T 2 * relaxation times. A recently published sequence, T 1 mApping with Partial Inversion Recovery (TAPIR), is used for T 1 mapping in a cohort of patients suffering from hepatic encephalopathy (HE). TAPIR enables the fast and precise measurement of T 1 with whole brain coverage in approximately 5 min, which makes it a favourable tool for clinical applications. A clear correlation between HE severity and T 1 measured with TAPIR is demonstrated for several brain regions. Patients and control subjects could be classified solely based on their T 1 pattern by making use of unsupervised pattern recognition tools. In addition, a newly developed sequence termed QUanTitativE-EPI (QUTE-EPI) is presented for the fast and precise mapping of T 2 * without significant image distortions. The information provided by TAPIR and QUTE-EPI can be used to extract an absolute measure of water content in vivo by MRI. The procedure of H 2 O content mapping is described and results are presented. We demonstrate that in vivo water measurement is possible in clinically relevant measurement times with a statistical and systematic measurement error