Single vs. multi-slice assessments of in vivo placental T2∗ measurements.

Introduction: Placental health is vital for maternal and fetal well-being, and placental T2∗ has been suggested to identify in vivo placental dysfunction prior to delivery. However, ideal regions of interest to best inform functional assessments of the placenta remain unknown. The aim of this study is to compare global and slice-wise measures of in-vivo placental T2∗ assessments.

Methods: This prospective study recruited pregnant people with singleton pregnancies between December 2017 and February 2022.3D multi-echo RF-spoiled gradient echo sequences were acquired, and placental T2∗ values were derived from global and slice-wise approaches. Statistical analyses included Pearson correlation coefficients, concordance correlation coefficients (CCC), intraclass correlation coefficients (ICC), and Bland-Altman analyses.

Results: Of 115 participants (mean gestational age, 29.25 ± 5.05 weeks), 68 were healthy controls, and 47 were high-risk pregnancies. Global and slice-wise placental T2∗ assessments for the entire cohort showed no significant difference nor for individual subgroups (healthy controls or high-risk). Pearson correlation values ranged between 0.88 and 0.99 for mean global and slice-wise placental T2∗. CCC analyses ranged from 0.88 to 0.99 for mean T2∗, and ICC analyses ranged between 0.88 and 0.99 for mean T2∗, showing a strong agreement between measurements. Bland-Altman analyses depicted T2∗ differences across coverage methods, and groups resided within the 95 % limits of agreement.

Discussion: Single-slice placental assessments offer robust, comparable T2∗ values to global assessments, with the added benefit of reducing post-processing time and SAR exposure. This supports slice-wise approaches as valid alternatives for assessing placental health in various pregnancies.