Correlation of placental thickness and PAS disorders: findings from MRI

Abstract

Objective: To identify if placental thickness measured from MRI images correlates with placenta accreta spectrum (PAS) disorders.

Methods: Placental thickness of 245 patients was retrospectively measured from October 2016 to March 2020. The measurement was made at the thickest portion of the placenta on the mid-sagittal plane of the placenta from MRI by two independent radiologists. Surgical report and pathology of the delivered placenta were used as a reference standard. Association between clinical features, placental thickness, and PAS disorders was evaluated with univariate and multivariate analyses. The inter-reader and intra-reader reproducibility of the measurements and receiver operating characteristic curve analysis were also performed.

Results: Placental thickness was significantly higher in patients with PAS disorders (3.45 cm) than that in patients without PAS disorders (2.90 cm) (p < 0.05). Multivariate analyses revealed that prior cesarean section, placenta previa, and placental thickness > 4 cm were independent risk factors for PAS disorders. The inter-reader and intra-reader reproducibility of placental thickness measurement were 0.979 (95% CI 0.960-0.989) and 0.981 (95% CI 0.9640-0.990), respectively.

Conclusion: The reproducibility of the measurement made from MRI images was high between two radiologists. Patients with PAS disorders had increased placental thickness. Placental thickness > 4 cm correlated with PAS disorders.

Keywords: MRI; PAS disorders; Placental thickness.