266: Does magnetic resonance imaging change clinical management of morbidly adherent placenta?

Abstract

Magnetic resonance imaging (MRI) may provide data to guide clinical management of patients with suspected morbidly adherent placenta (MAP). Our objective was to explore whether MRI provides data that changes diagnosis and potential clinical management of patients with suspected MAP beyond that obtained by sonogram (US). Patients with US evidence or clinical suspicion for MAP underwent MRI in orthogonal planes through the uterus utilizing T1 and T2 weighted sequences at two tertiary care medical centers. We compared radiologic impressions of US versus MRI, and confirmed the radiologic impression with clinical or histologic diagnosis at the time of delivery. Change in diagnosis that could alter clinical management of MAP (e.g. planned hysterectomy or timing or location of delivery) as a result of MRI was defined a priori as any of the following: (1) confirmed case of MAP by MRI when US was uncertain, (2) upgrade to percreta/increta on MRI when US showed no percreta/increta, (3) MRI identified invasion of pelvic organs outside the uterus when US did not, or (4) downgrade to no MAP on MRI when ultrasound raised suspicion. Diagnoses were confirmed by clinical or histologic diagnosis at the time of delivery. Misdiagnoses of MRI included over- and under-diagnosis of MAP or percreta. Sixty-eight patients with US and MRI were evaluated. A change in diagnosis that could potentially alter clinical management occurred in 12 (18%) (Table). These included 8 cases upgraded to percreta (of which 5 correctly identified invasion of pelvic organs outside the uterus not previously identified by ultrasound), and 4 were downgrades from accreta to no accreta resulting in no need for hysterectomy. MRI correctly confirmed the US diagnosis in 36 (53%), but resulted in an incorrect upgrade or downgrade in 15 (22%) and 5 (7%) respectively. MRI was not more useful with posterior/lateral placental implantation, present in 29% of cases. MRI changed a diagnosis that could influence clinical management of MAP in 47% of cases. However, it was just as likely to lead to an incorrect diagnosis as a correct one. The utility of MRI in the setting of MAP remains to be determined.