Comparison of Different EPI-Based Approaches to Measure T2 in Human Brain for the Purpose of Oxygenation Measurements

Thomas Christen¹, Heiko Schmiedeskamp¹, Matus Straka¹, Roland Bammer¹, Greg Zaharchuk¹

We compared in this study three different EPI-based approaches for measuring T2 : (1) a subtraction of T2 from T2* relaxation rates that are derived from separate multiecho sequences; (2) an asymmetric spin echo (ASE) sequence; (3) a combined multiple gradient echo and spin echo (SAGE) sequence. The results obtained in the brain of 4 subjects suggest that the different approaches give similar T2 values. They however showed spatial differences. The highest-quality maps were obtained with the ASE method. The SAGE approach, while containing spatial artifacts, could be used in a dynamic approach with high time resolution.