Risk factors of MRI findings for predicting patient outcomes of placenta accreta spectrum and placenta previa after prophylactic balloon occlusion of the internal iliac artery

Purpose: Our study aimed to identify the risk factors of magnetic resonance imaging (MRI) findings for predicting patient outcomes of placenta accreta spectrum (PAS) and placenta previa after prophylactic balloon occlusion of the internal iliac artery (PBOIIA).Materials and methods: This retrospective analysis was performed using the clinical records of 46 patients diag-nosed with PAS and placenta previa who underwent PBOIIA during caesarean section (CS). The possible clinical risk factors for adverse maternal outcomes were evaluated by consulting patients' clinical records. The inclusion criteria for the massive bleeding group were as follows: estimated blood loss (EBL) > 2500 mL, packed red blood cell (pRBC) transfusion (>4 units), and need for hysterectomy or transcatheter arterial embolization after de-livery. The MRI features were compared between the massive and non-massive bleeding groups.Results: Patients in the massive bleeding group (n = 22) had a significantly longer operation time (p < 0.001), more EBL (p < 0.001), more pRBC transfusions (p < 0.001), and a prolonged postoperative hospital stay (p < 0.05). MRI features showed a T2 dark bands, placenta bulge, and abnormal blood vessels in the placental bed more frequently in the massive bleeding group (p < 0.05). In the multiple logistic regression analysis, T2 dark bands (odds ratio 9.1, p = 0.048) and placental bulge (odds ratio 5.1, p = 0.014) remained statistically significant.Conclusion: T2 dark bands and placental bulges observed on an MRI can predict adverse maternal outcomes in patients with PAS and placenta previa undergoing PBOIIA. If these findings are observed on a preoperative MRI, effective management strategies should be prepared for the possibility of massive hemorrhage during CS.