Comparison of MRI methods for measuring whole‐brain venous oxygen saturation

Purpose In this work, we compare susceptometry‐based oximetry (SBO) and two T 2 ‐based methods for estimating resting baseline SvO 2 in the superior sagittal sinus (SSS). Methods SBO is a field‐mapping technique whereas in T 2 ‐based methods the intravascular blood signal is isolated either with velocity‐encoded projections [projection‐based T 2 (PT 2 )] or a tag‐control scheme [T 2 ‐relaxation under spin tagging (TRUST)] after T 2 ‐preparation. The measurements were performed on twelve healthy subjects (mean age = 33 ± 6 years) at 3 Tesla field strength. The reliability, precision, and reproducibility were examined for the three techniques. Results The mean (± standard deviation) SvO 2 quantified by SBO, PT 2 , and TRUST were found to be 65.9 ± 3.3, 65.6 ± 3.5, and 63.2 ± 4.1%. The standard deviation (SD) for 10 consecutive measurements in the quantified SvO 2 was less than 2.7%, 4.7%, and 5.0% for SBO, PT 2 , and TRUST across all subjects. In testing reproducibility across different days, the resulting SDs were 2.6, 3.5, and 2.0% for SBO, PT 2 , and TRUST. Conclusion The results indicate that all three SvO 2 quantification techniques to be reliable with good agreement between PT 2 and SBO while TRUST yielded slightly lower values compared with the other two techniques. Magn Reson Med 73:2122–2128, 2015. © 2014 Wiley Periodicals, Inc.