Multisite evaluations of a T₂-relaxation-under-spin-tagging (TRUST) MRI technique to measure brain oxygenation

Purpose Venous oxygenation (Y_v) is an important index of brain physiology and may be indicative of brain diseases. A T₂-relaxation-under-spin-tagging (TRUST) MRI technique was recently developed to measure Y_v. A multisite evaluation of this technique would be an important step toward broader availability and potential clinical utilizations of Y_v measures. Methods TRUST MRI was performed on a total of 250 healthy subjects, 125 from the developer's site and 25 each from five other sites. All sites were equipped with a 3 Tesla (T) MRI of the same vendor. The estimated Y_v and the standard error (SE) of the estimation ε_Yv were compared across sites. Results The averaged Y_v and ε_Yv across six sites were 61.1% ± 1.4% and 1.3% ± 0.2%, respectively. Multivariate regression analysis showed that the estimated Y_v was dependent on age (P = 0.009) but not on performance site. In contrast, the SE of the Y_v estimation was site-dependent (P = 0.024) but was less than 1.5%. Further analysis revealed that ε_Yv was positively associated with the amount of subject motion (P < 0.001) but negatively associated with blood signal intensity (P < 0.001). Conclusion This work suggests that TRUST MRI can yield equivalent results of Y_v estimation across different sites.