Evaluation of the placenta with relative apparent diffusion coefficient and T2 signal intensity analysis.

PURPOSE We aimed to test the null hypothesis that relative apparent diffusion coefficient (rADC) and relative signal intensity values (rSI(HASTE)) do not change in the evaluation of placental maturation with advancing gestational age. MATERIALS AND METHODS Fifty-six fetuses with diffusion-weighted magnetic resonance imaging (DW-MRI) data were enrolled in this retrospective study. Fetuses were analyzed in three different gestational age groups: group 1, 18-23 weeks; group 2, 24-28 weeks; and group 3, 29-38 weeks. The rADC (mean ADC/ADC(globe)) and rSI(HASTE) values (mean SI(HASTE)/SI(globe)) were obtained. Two radiologists experienced in fetal MRI who were blinded to the patient information reviewed MRI images independently. Kruskal-Wallis Test was used to compare the rADC and rSI(HASTE) with gestational age groups. The agreement between the two blinded readers was tested using Krippendorff's alpha ratio. RESULTS Both placental rADC values and placental rSI(HASTE) values were not significantly different between the gestational age groups (P = 0.688 and P = 0.280, respectively). rADC and rSI(HASTE) measurements were reproducible with a good agreement between the two readers (Krippendorff's alpha ratio was 0.613 and 0.778, respectively). CONCLUSION The rADC and rSI(HASTE) values do not change with advancing gestational age.