MR Evaluation of Placenta Accreta Spectrum: Concordance Rates and Effect of Structured Reporting on Patient Outcomes

Objective: To examine the concordance rate of MRI findings with intraoperative and pathologic findings in patients with Placenta Accreta Spectrum (PAS), as well as the use of structured reporting, and their relationship to clinical outcomes.

Methods: An IRB approved retrospective chart review was performed for patients with a history of cesarean delivery, a diagnosis of PAS on post-operative pathology report, and a placental MRI prior to delivery between 2008-2022. Concordance rates were calculated between final MRI, ultrasound, operative, and pathologic diagnoses, as well as impact on clinical outcomes. Quantitative variables were analyzed using a t-test. Categorical variables were analyzed using chi-squared and Fischer's exact tests.

Results: A total of 59 patients met initial inclusion criteria. Of these 59 patients, 8 (13.6%) were interpreted using structured reporting. Discordance between preoperative imaging, operative findings and final pathology diagnoses were associated with increased blood loss, blood transfusion, ICU admission, and postpartum length of stay. Structured reporting was found to significantly reduce the amount of diagnostic discordance (p=.017) and was associated with decreased ICU admissions when utilized (p=.045).

Conclusions: Use of structured reporting in the interpretation of placental MRI may decrease the amount of discordance between imaging and intraoperative or pathologic diagnoses, which in our study is associated with improved patient outcomes including decreased blood loss and amount of blood transfused. Radiologists must be cognizant of key imaging features of PAS on MRI, as interpretation provides an opportunity to positively impact the quality and safety of patient care.