MRI Significantly Improves Disease Staging to Direct Surgical Planning for Abnormal Invasive Placentation: A Single...

To describe the role of ultrasound and MRI in defining the extent of disease and guiding perioperative and surgical management of abnormal invasive placentation (AIP).

We conducted a review of 65 cases of invasive placentation diagnosed antenatally with use of ultrasound and/or MRI in a single tertiary centre between January 2000 and December 2014. Cases were assigned a grade based on the depth of invasion and location of invasion within the uterus as described in ultrasound and MRI reports. These grades were then compared with grades assigned using a combination of pathology and dictated surgical reports.

Ultrasound correctly identified the presence of AIP in 91.9% of cases but was accurate in predicting the stage of invasion in only 38.7% of cases. Ultrasound identified only 6.3% of cases with parametrial involvement. MRI correctly identified the presence of AIP in 98.4% of cases and was accurate in predicting the stage of invasion in 61.3% of cases. MRI accurately detected parametrial involvement in 68.8% of cases.

Our results suggest that all women with signs of AIP on ultrasound scanning should be referred for MRI to assess the extent of placental invasion adequately and consequently to allow for adequate perioperative and surgical planning for delivery.