The measurement of fetal liver T-2(*) in utero before and after maternal oxygen breathing: progress towards a non-invasive measurement of fetal oxygenation and placental function

Utero-placental insufficiency is thought to be a major cause of growth reta rdation in utero and an important risk factor in the perinatal period. The purpose of this study was to investigate whether MRI could detect changes o f fetal oxygenation, based on the blood oxygenation level dependence (BOLD) of the MRI tissue signal. Nine third trimester women (34-38 weeks) with no rmal pregnancies underwent abdominal MRI examinations. Following localizati on of the fetal liver using T-2-weighted single-shot HASTE scans, up to 7 b reath-held transaxial single-slice gradient-echo image sets were obtained t hrough the fetal liver. The mother then commenced oxygen breathing with the imaging procedure repeated after 20 minutes of O-2 breathing. For each ima ge set, T-2(*) values are calculated using linear regression of log (signal ) versus TE for a region of interest within the fetal liver selected by the attending radiologist. Fetal liver T-2(*) values were calculated before an d after O-2 breathing for each multi-echo image acquisition set. A signed r ank test was used to test for a significant change in fetal liver T-2(*) be tween the pre-O-2 and post-O-2 image sets. A significant increase in T-2(*) (alpha < 0.05) was seen in 5 of the 9 fetal livers, a smaller increase (of borderline statistical significance, alpha = 0.057) in 2 livers, and no si gnificant change (alpha > 0.05) in 2 livers. Our study indicates that T-2(* ) measurement of the fetal liver may detect alteration in fetal oxygen leve l following maternal oxygenation using the BOLD effect. This technique may potentially be applied to the identification and understanding of placental dysfunction in intra-uterine growth retardation. (C) 2001 Elsevier Science Inc. All rights reserved.