MRI Significantly Improves Disease Staging to Direct Surgical Planning for Abnormal Invasive Placentation: A Single Centre Experience.
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.
Department of Obstetrics and Gynaecology, University of Toronto, Toronto ON; Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON.
Kara
K
Aitken
Department of Obstetrics and Gynaecology, University of Toronto, Toronto ON; Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON.
Lisa
L
Allen
Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON; Department of Medical Imaging, University of Toronto, Toronto ON.
Sophia
S
Pantazi
Department of Obstetrics and Gynaecology, University of Toronto, Toronto ON; Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON; Department of Medical Imaging, University of Toronto, Toronto ON; Department of Laboratory Medicine and Pathobiology University of Toronto, Toronto ON.
John
J
Kingdom
Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON; Department of Laboratory Medicine and Pathobiology University of Toronto, Toronto ON.
Sarah
S
Keating
Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON.
Lindsay
L
Pollard
Department of Obstetrics and Gynaecology, University of Toronto, Toronto ON; Department of Obstetrics and Gynaecology, Mount Sinai Hospital, Toronto ON.
Rory
R
Windrim
D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D010921:Placenta Accreta / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D011247:Pregnancy; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal
Placenta accreta; invasive placentation; magnetic resonance; placenta percreta; surgical planning; ultrasonography