Placenta Accreta: Diagnostic Accuracy of Ultrasonography Versus MRI

Abstract
Background: Placenta accreta is an aberrant attachment of the placenta within the myometrium due to the absence of decidua basalis with subsequent infiltration of the myometrium by chorionic villi.
Aim of Study: The present study aimed to construct the basic criteria of both sonographic and MRI for the diagnosis of placenta accrete and figuring out the accuracy of those criteria parallel with the definition of the most peculiar features in clinical practice.
Material and Methods: 84 pregnant women at high risk of placenta accrete occurrence from two Obstetric Centers; Saudi German and Sulaiman Alhabib Hospitals, Riyadh, KSA, have been disgnosed in the period from January 2015 to May 2017. All patients did abdominal ultrasonography and MRI to evaluate the suspected diagnosis of placenta accreta. A comparison was made between the results of both procedures and the final diagnosis that was confirmed by clinical findings at delivery and pathologic examination of specimens.
Results: No significant difference in the sensitivity and specificity of ultrasonography and MRI (sensitivity: Ultra-sonography, 100% versus MRI, 76.9%, specificity: Ultra-sonography, 37%, versus MRI, 50%). Incongruence was found in 28 of 84 cases between ultrasonography and MRI. In these, ultrasonography was correct in 16 cases, and MRI was correct in 12 cases. This was statistically non-significant.
Conclusion: Both modalities have nearly the same diag-nostic accuracy. Ultrasonography is the commonly used and the most sensitive imaging method. Moreover, MRI acts as a perfect complement method to ultrasonography in case of the presence of few inconclusive ultrasound findings.