Reena Malhotra MD, Abstract Co-Author: Nothing to Disclose

Lorene Elaine Romine MD, Abstract Co-Author: Nothing to Disclose

Robert Frederick Mattrey MD, Abstract Co-Author: Nothing to Disclose

Michele Anne Brown MD, Presenter: Nothing to Disclose

Placenta accreta, or invasive placenta, is a leading cause of perinatal maternal mortality. The incidence of placenta accreta has increased dramatically in the past 50 years. Antenatal diagnosis is difficult, yet critical to minimize mortality and morbidity. The purpose of this study is to evaluate the accuracy of magnetic resonance (MR) imaging for the diagnosis of invasive placenta.

108 patients underwent MR evaluation for possible placenta accreta between 1992 and 2009. Patients were referred for MR due to suspicious prenatal ultrasound and/or significant risk factors and high clinical suspicion. Surgical and/or pathology results were available in 71 of 108 cases. Prospective imaging interpretations were retrospectively correlated with subsequent surgical and pathology findings to determine accuracy. Retrospective analysis of MR images was performed in order to generate a list of the most reliable and specific diagnostic criteria.

When correlated with surgical and pathology findings, MR demonstrated a sensitivity of 87.8 %, specificity of 95.5 %, and accuracy of 90.1 %. Positive predictive value was 97.7 %, and negative predictive value was 77.8 %. The most accurate diagnostic imaging features were abnormal uterine contour and abnormal placental signal, including dark bands on T2-weighted images. For cases in which the MR diagnosis of invasive placenta was uncertain, gadolinium administration was helpful to distinguish the maternal-placental interface and improve diagnostic confidence.

MR is an extremely useful adjunct to ultrasound for assessing possible invasive placenta, a potentially life-threatening obstetric condition. Diagnostic MR imaging features of invasive placenta include uterine contour abnormality, placental signal abnormality, including dark bands on T2-weighted images, and abnormal gadolinium enhancement. KEY WORDS: Placenta, Previa, Accreta, Magnetic Resonance, Diagnosis, Ultrasound  

 

Malhotra, R, Romine, L, Mattrey, R, Brown, M, MR Imaging of Placenta Accreta.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8011711.html