Factors affecting performance of fetal blood T 2 measurements for noninvasive estimation of oxygen saturation.

Errors due to T -fitting techniques, off-resonance, flow velocity, and insufficient T recovery between image acquisitions could be mitigated by using three-parameter fitting with included saturation-prepared images approximating infinite T -preparation time, adequate shimming covering the fetus and placenta, and by modifying acquisition parameters. Variability in fetal blood T and sO , however, indicate that it is currently not feasible to use these methods for prediction of disease.