Role of Magnetic Resonance Imaging in the Antenatal Diagnosis of Placenta Accreta - A Case Report

Antenatal Diagnosis of Placenta Accreta by MRI

Abstract

Placenta Previa (PP) is the abnormal presence of placenta in front of internal os and can be classified into three types (Marginal, partial and complete PP. Transabdominal ultrasound is an effective modality to evaluate PP. Placenta Accreta (PA) occurs when chorionic villi insert deep into the myometrium due to imperfection of decidua basalis. PA is classified on the basis of myometrial invasion. The mildest form of PA is placenta accreta Vera which is classified as attachment of chorionic villi to the myometrium but sparing the muscle. There are 10% chances of PA in women with the initial diagnosis of PP. Previous cesarean section and advanced maternal age are independent risk factors for this high-risk group. Undiagnosed PP is related to significant maternal mortality (up to 25%) and morbidity which occurs due to intrapartum hemorrhage, uterine rupture, abscess formation, and bladder and rectum invasion. The reliability of Brightness mode and color Doppler ultrasound varies widely in different studies for antenatal diagnosis of PA. Magnetic resonance imaging, with and without gadolinium contrast, has been scrutinized as the modality for the greater precision of the antenatal diagnosis of PA in recent times.

Objective: To assess whether Magnetic Resonance Imaging is an effective modality to rule out placenta accreta, increta, or percreta antenatally. Subject and

Method: Ultrasound and Magnetic Resonance Imaging (MRI) was performed on one pregnant female with PP prior to delivery. Delivery plan was made according to imaging suggestion of the degree of PP and presence/absence of PA. Findings at cesarean section were considered the gold standard of reference.

Conclusion: MRI with ultrasound is important for the accurate diagnosis of PPand the seriously co-existing PA.