Evaluation of the placental maturation with apparent diffusion coefficient

Objective: To explore the efficacy of apparent diffusion coefficient (ADC) value for assessing placental maturation. Methods: 48 women with singleton pregnancy (gestational age range: 18 weeks 1 day to 38 weeks 5 days, average: 27 weeks 6 days) underwent fetal MRI within 72 hours after conventional prenatal ultrasonography (US) demonstrated fetal malformations and normal placenta. Using a 3 T MR scanner, half Fourier single-shot turbo spin-echo (HASTE) and fat-saturated T₁-weighted sequences followed by diffusion-weighted MR imaging with b value of 1000 were acquired. The women were divided into three groups according to gestational age. The ADC values were measured by 2 observers and the average ADC values of the 3 gestational age groups were compared by Kruskal-Wallis H test. Results: The median ADC value of 48 normal placentas was 1.899 ± 0.114 × 10^-3 mm²/s with range of 1.723-2.140 × 10^-3 mm²/s. The ADC values of placentas measured by the 2 observers were in good agreement (ICC = 0.901, P < 0.05). There was no significant difference in ADC values of placentas among the 3 gestational age groups (P > 0.05). Conclusion: With increasing gestational age, the ADC value of placenta remains relatively stable and cannot be used to measure placental maturity. (authors)