Comparative Diagnostic Accuracy of Ultrasound and Magnetic Resonance Imaging in Placenta Accreta Spectrum Disorder: An experience from a tertiary care centre

Objective: This study aims to prospectively evaluate and compare the diagnostic performance of ultrasound (US) and magnetic resonance imaging (MRI) in women at high risk for Placenta Accreta spectrum (PAS) disorder and to assess their complementary roles in clinical management.

Methods: In this prospective observational study, 30 pregnant women with suspected PAS disorder were evaluated between 18 and 35 weeks of gestation. All patients underwent both transabdominal ultrasound with color Doppler, followed by MRI. Imaging findings were compared to intraoperative findings and histopathological diagnoses. Histopathological diagnosis was considered the gold standard.

Results: The ages of patients ranged from 22 to 41 years. Out of the total 30 patients, 27 were confirmed to have PAS (20 accreta, 4 increta, 3 percreta). On correlation of US and MRI diagnosis with intraoperative and histopathological findings, US has a sensitivity of 92.6%, a specificity of 100%, a positive predictive value of 100% but a negative predictive value of 60%. Accuracy of US against intraoperative findings was 93.3%. However, MRI was false positive in one case; consequently, MRI had a sensitivity and specificity of 96.7% and 100% respectively. MRI had a positive predictive value of 100% but a negative predictive value of 75%. The accuracy of MRI against intraoperative findings was 96.7%. MRI was superior in detecting posterior placentation and parametrial invasion.

Conclusion: Both US and MRI are valuable tools for diagnosing PAS, with MRI showing marginally higher sensitivity, especially in complex or posterior cases. A combined approach enhances diagnostic confidence and surgical planning, potentially improving maternal outcomes.