Comparative analysis of ultrasound and MRI in the diagnosis of placenta accreta spectrum

Objectives: Placenta accreta spectrum constitutes one of the most complicated challenges in modern obstetrics. Given the conflicting data regarding the added value of MRI in the diagnosis of invasive placentation, we aim to assess individual and combined ability of multiple sonographic and MRI signs to diagnose placenta accreta spectrum in suspected cases. Methods: We assessed 28 cases of suspected placenta accreta spectrum in the third trimester. All cases underwent ultrasound assessment as well as MRI scan. Diagnosis was confirmed during surgery. The value of sonographic and MRI signs in the detection of placenta accreta spectrum was assessed. Results: A total of 23 cases were diagnosed with placenta accreta spectrum during cesarean delivery. Overall, ultrasound was found to be more sensitive and specific compared to MRI (sensitivity of 0.96 and specificity of 0.6 in ultrasound vs. sensitivity of 0.83 and specificity of 0.4 in MRI). However, the use of a post-hoc structured model improved MRI performance to a similar level of ultrasound (sensitivity of 0.96 and specificity of 0.6). Conclusions: Ultrasound is superior to MRI in the detection of placenta accreta spectrum. However, MRI performance can be greatly improved by the use of a structured scoring system.