Value of Magnetic Resonance Spectroscopy for Examining Fetal Brain Development in Mid‐ to Late Pregnancy

ABSTRACT Background Magnetic resonance spectroscopy (MRS) represents a significant advancement in the noninvasive assessment of brain metabolism. MRS can provide valuable metabolic information and facilitate more accurate diagnoses of intrauterine fetal brain development than was previously possible. To obtain information regarding normal intrauterine fetal brain metabolism and to establish gestational age‐specific reference values for normal fetal brain metabolites for subsequent use in MRS, we conducted MRS scans of normal fetal brains during mid‐ to late‐term pregnancies, along with related processing. Methods In this prospective study, MRS scans were conducted on 109 fetuses, with a total of 54 normal fetal brains enrolled on the basis of specific inclusion and exclusion criteria. We analyzed metabolic ratios, including the sum of N‐acetylaspartate (NAA) and total N‐acetylaspartate (tNAA), total choline (tCho), inositol (Ins), and total creatine (tCr), in relation to gestational age. Results Gestational age was significantly correlated with specific metabolic ratios (Ins/tCr: r = −0.75, p < 0.0001; tCho/tCr: r = −0.50, p < 0.0001), especially tNAA/tCho (tNAA/tCho: r = 0.54, p < 0.0001) and tNAA/Ins ( r = 0.56, p < 0.0001), providing a baseline for fetal brain metabolic assessment. Linear regression analysis was used to calculate regression lines for fetal brain metabolite ratios. Slopes were tested at p of 0.05. Conclusions The current findings confirmed a significant correlation between fetal brain metabolites and gestational age, supporting the feasibility of establishing standard values for these metabolites in fetal brain assessment.