1H HR-MAS spectroscopy for quantitative measurement of choline concentration in amniotic fluid as a marker of fetal lung maturity: Interand intraobserver reproducibility study

Bonnie N. Joe, Kiarash Vahidi, Andrew Zektzer, Mei Hsiu Chen, Matthew S. Clifton, Thomas Butler, Kayvan Keshari, John Kurhanewicz, Fergus Coakley, Mark G. Swanson

Research output: Contribution to journalArticle

19 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1540-1545
Number of pages6
JournalJournal of Magnetic Resonance Imaging
Issue number6
StatePublished - Dec 2008



  • Amniotic fluid
  • Fetal lung maturity
  • High resolution magic angle spinning (HR-MAS)
  • Reproducibility

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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