Placental vascularity and resorption delay after conservative management of invasive placenta: MR imaging evaluation.

OBJECTIVES: To assess the potential of magnetic resonance (MR) imaging in evaluating placental vascularity and predicting placental resorption delay after conservative management of invasive placenta.
METHODS: MR examinations of 23 women with conservative management of invasive placenta were reviewed. Twelve women had pelvic embolisation because of postpartum haemorrhage (Group 1) and 11 had no embolisation (Group 2). Comparisons between the two groups were made with respect to the delay for complete placental resorption at follow-up MR imaging and degree of placental vascularity 24 h after delivery on early (30s) and late (180 s) phase of dynamic gadolinium chelate-enhanced MR imaging.
RESULTS: The median delay for complete placental resorption in the cohort study was 21.1 weeks (range, 1-111 weeks). In Group 1, the median delay for complete placental resorption was shorter than in Group 2 (17 vs 32 weeks) (P = 0.036). Decreased placental vascularity on the early phase was observed in Group 1 by comparison with Group 2 (P = 0.003). Significant correlation was found between the degree of vascularity on early phase of dynamic MR imaging and the delay for complete placental resorption (r = 0.693; P < 0.001).
CONCLUSIONS: MR imaging provides useful information after conservative management of invasive placenta and may help predict delay for complete placental resorption.