Placenta Accreta Spectrum and Modality of Choice For Placental Mapping as Confirmed with Intraoperative Findings

Abstract

Objective: To find diagnostic accuracy of magnetic resonance imaging (MRI) and color doppler
ultrasound for placenta accreta spectrum (PAS) by comparing them with intra operative findings.
Methods: This study was conducted at Lahore General Hospital, Lahore and Services Hospital,
Lahore from 01-07- 2017 to 31-01- 2020. 36 pregnant patients with history of previous cesarean
sections and ultrasound documentation of placenta previa at more than or equal than 32 weeks
of gestation were included in the study. Both color doppler ultrasound and MRI evaluation for PAS
were performed on all patients included in the study. Findings were confirmed intra operatively.
Women with upper uterine segment placenta were excluded.
Results: Out of 36 patients enrolled for the study, color doppler USG confirmed diagnosis of
PAS in 30 patients while MRI confirmed diagnosis of PAS in 31 patients. Intra operatively PAS
was confirmed in 31 patients. Color doppler USG yielded 2 false negative cases and 1 false
positive case with sensitivity, specificity, accuracy, positive predictive value and negative
predictive value of 93.54%,( 95% confidence interval [CI] , 77% to 98%), 80.0% (95% CI, 29% to
98%), 91.66%, 96.6%, 66.66% respectively while MRI yielded 1 false negative and 1 false
positive case with all these values as 96.77% (95% CI, 81% to 99%), 80.0% (95% CI, 29% to
98%), 94.44%, 96.77%, 80.0% respectively.
Conclusions: Color doppler ultrasound and MRI are complementary investigations. MRI has
superior sensitivity than color doppler USG but the specificity of both modalities are same for
antenatal diagnosis of PAS.