Purpose: To determine the intra- and interobserver reproducibility of human amniotic fluid metabolite concentration measurements (including potential markers of fetal lung maturity) detectable by MR spectroscopy. Materials and Methods: 1H high-resolution magic angle spinning (HR-MAS) spectroscopy was performed at 11.7T on 23 third-trimester amniotic fluid samples. Samples were analyzed quantitatively using 3-(trimethylsilyl)propionic- 2,2,3,3-d4 acid (TSP) as a reference. Four observers independently quantified eight metabolite regions (TSP, lactate doublet and quartet, alanine, citrate, creatinine, choline, and glucose) twice from anonymized, randomized spectra using a semiautomated software program. Results: Excellent inter- and intraobserver reproducibility was found for all metabolites. Intraclass correlation as a measure of interobserver agreement for the four readers ranged from 0.654 to 0.995. A high correlation of 0.973 was seen for choline in particular, a major component of surfactant. Pearson correlation as a measure of intraobserver reproducibility ranged from 0.478 to 0.999. Conclusion: Quantification of choline and other metabolite concentrations in amniotic fluid by high-resolution MR spectroscopy can be performed with high inter- and intraobserver reproducibility. Demonstration of reproducible metabolite concentration measurements is a critical first step in the search for biomarkers of fetal lung maturity.
- Amniotic fluid
- Fetal lung maturity
- High resolution magic angle spinning (HR-MAS)
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging