Accuracy of ultrasound for the detection of placenta accreta spectrum in a universal screening population

Abstract

Objectives: The current study aimed to determine the sensitivity and specificity of ultrasound for the diagnosis of placenta accreta spectrum (PAS) in a universal screening population and assesses the added value of magnetic resonance imaging (MRI). Methods: This retrospective analysis evaluated 5219 patients with singleton pregnancies who had a standardized ultrasound (US) examination in our unit and delivered at our institution between 2014 and 2019. Results: A total of 181 (3.5%) of 5219 (100%) patients had a suspicion or diagnosis of PAS with US. The accuracy of US in detecting placenta increta/percreta showed a sensitivity of 100%, specificity of 99.9%, positive predictive value of 82.4%, and a negative predictive value of 100%. The diagnosis of all forms of PAS showed a sensitivity of 25.8%, specificity of 99.8%, positive predictive value of 80.8%, and a negative predictive value of 97.7%. MRI was concordant with US in 11 of 14 (78.5%) cases of severe forms of PAS and in three of 15 (20.0%) cases with placenta accreta. Conclusion: A standardized US evaluation can be applied in a universal screening setting for the diagnosis of severe forms of PAS. MRI is a complementary examination in severe forms of PAS but seems of limited value to discriminate placenta accreta from placenta increta/percreta.