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

作者：Erik Hedström, Marjolein Piek, Sebastian Bidhult‐Johansson, Daniel Ryd, Frederik Testud, Johannes Töger, Anthony H. Aletras · 发表于：Magnetic Resonance in Medicine · 年份：2023 · DOI：10.1002/mrm.29821 · 被引用次数：2 · 研究领域：Advanced MRI Techniques and Applications、MRI in cancer diagnosis、Neonatal and fetal brain pathology

Abstract Purpose To ultimately make accurate and precise fetal noninvasive oxygen saturation (sO 2 ) measurements by T 2 ‐prepared bSSFP more widely available by systematically assessing error sources in order to potentially reduce perinatal mortality in cardiovascular malformations and fetal growth restriction. Methods T 2 ‐prepared bSSFP data were acquired in phantoms; in flowing blood in adults in the superior sagittal sinus, ascending and descending aorta, and main pulmonary artery; and in the fetal descending aorta and umbilical vein. T 2 was assessed in relation to T 2 two‐ or three‐parameter curve‐fitting techniques, SSFP readout, refocusing time delay ( τ ), constant and pulsatile blood flow, and impact of T 1 recovery. Further, fetal T 2 and sO 2 variability were quantified in the descending aorta and umbilical vein in healthy fetuses and fetuses with cardiovascular malformation (gestational weeks 32–38). Results In phantoms, three‐parameter fitting was accurate irrespective of phase FOV (<4 ms; i.e., <2%), and T 2 was overestimated (up to 23 ms/10%; p = 0.001) beyond ±30 Hz off‐resonance. In the adult aorta, T 2 was underestimated during higher blood flow velocities and pulsatility for τ = 16 ms (−41 ms/−17%; p = 0.008). In fetuses, two‐parameter fitting overestimated T 2 compared with three‐parameter fitting (+33 ms/+18%; p = 0.03). T 2 variability was 18 ms/15% in the fetal descending aorta and 28 ms/14% in the umbilical vein. The resulting estimated sO 2 va...