Abdominal Radiology

, Volume 44, Issue 7, pp 2572–2581 | Cite as

Placenta accreta spectrum: value of placental bulge as a sign of myometrial invasion on MR imaging

  • Priyanka JhaEmail author
  • Joseph Rabban
  • Lee-may Chen
  • Ruth B. Goldstein
  • Stefanie Weinstein
  • Tara A. Morgan
  • Dorothy Shum
  • Nancy Hills
  • Michael A. Ohliger
  • Liina Poder



To evaluate correlation of “placental bulge sign” with myometrial invasion in placenta accreta spectrum (PAS) disorders. Placental bulge is defined as deviation of external uterine contour from expected plane caused by abnormal outward bulge of placental tissue.

Materials and methods

In this IRB-approved, retrospective study, all patients undergoing MRI for PAS disorders between March 2014 and 2018 were included. Patients who delivered elsewhere were excluded. Imaging was reviewed by 2 independent readers. Surgical pathology from Cesarean hysterectomy or pathology of the delivered placenta was used as reference standard. Fisher’s exact and kappa tests were used for statistical analysis.


Sixty-one patients underwent MRI for PAS disorders. Two excluded patients delivered elsewhere. Placental bulge was present in 32 of 34 cases with myometrial invasion [True positive 32/34 = 94% (95% CI 0.80–0.99)]. Placental bulge was absent in 24 of 25 cases of normal placenta or placenta accreta without myometrial invasion [True negative = 24/25, 96% (95% CI 80–99.8%)]. Positive and negative predictive values were 97% and 96%, respectively. Placental bulge in conjunction with other findings of PAS disorder was 100% indicative of myometrial invasion (p < 0.01). Kappa value of 0.87 signified excellent inter-reader concordance. In 1 false positive, placenta itself was normal but the bulge was present. Surgical pathology revealed markedly thinned, fibrotic myometrium without accreta. One false-negative case was imaged at 16 weeks and may have been imaged too early.


Placental bulge in conjunction with other findings of invasive placenta is 100% predictive of myometrial invasion. Using the bulge alone without other signs can lead to false-positive results.


Placenta accreta spectrum PAS disorder Placental bulge Uterine bulge MR imaging Placenta increta Myometrial invasion 



  1. 1.
    Jauniaux E, et al. (2018) FIGO consensus guidelines on placenta accreta spectrum disorders: Epidemiology. Int J Gynaecol Obstet 140(3):265–273CrossRefGoogle Scholar
  2. 2.
    Jauniaux E, Collins S, Burton GJ (2018) Placenta accreta spectrum: pathophysiology and evidence-based anatomy for prenatal ultrasound imaging. Am J Obstet Gynecol 218(1):75–87CrossRefGoogle Scholar
  3. 3.
    Solheim KN, et al. (2011) The effect of cesarean delivery rates on the future incidence of placenta previa, placenta accreta, and maternal mortality. J Matern Fetal Neonatal Med 24(11):1341–1346CrossRefGoogle Scholar
  4. 4.
    Fitzpatrick, K.E., et al., The management and outcomes of placenta accreta, increta, and percreta in the UK: a population-based descriptive study. BJOG, 2014. 121(1): p. 62-70; discussion 70-1.Google Scholar
  5. 5.
    Thurn L, et al. (2016) Abnormally invasive placenta-prevalence, risk factors and antenatal suspicion: results from a large population-based pregnancy cohort study in the Nordic countries. BJOG 123(8):1348–1355CrossRefGoogle Scholar
  6. 6.
    Miller DA, Chollet JA, Goodwin TM (1997) Clinical risk factors for placenta previa-placenta accreta. Am J Obstet Gynecol 177(1):210–214CrossRefGoogle Scholar
  7. 7.
    Allen L, et al. (2018) FIGO consensus guidelines on placenta accreta spectrum disorders: Nonconservative surgical management. Int J Gynaecol Obstet 140(3):281–290CrossRefGoogle Scholar
  8. 8.
    Creanga, A.A., et al., Morbidity associated with cesarean delivery in the United States: is placenta accreta an increasingly important contributor? Am J Obstet Gynecol, 2015. 213(3): p. 384 e1-11.Google Scholar
  9. 9.
    Chantraine F, et al. (2012) Individual decisions in placenta increta and percreta: a case series. J Perinat Med 40(3):265–270CrossRefGoogle Scholar
  10. 10.
    Brookfield KF, et al. (2014) Perioperative and transfusion outcomes in women undergoing cesarean hysterectomy for abnormal placentation. Transfusion 54(6):1530–1536CrossRefGoogle Scholar
  11. 11.
    Grace Tan SE, et al. (2013) Surgical management of placenta accreta: a 10-year experience. Acta Obstet Gynecol Scand 92(4):445–450CrossRefGoogle Scholar
  12. 12.
    Woldu SL, et al. (2014) Urologic considerations of placenta accreta: a contemporary tertiary care institutional experience. Urol Int 93(1):74–79CrossRefGoogle Scholar
  13. 13.
    Jauniaux E, Bhide A (2017) Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis. Am J Obstet Gynecol 217(1):27–36CrossRefGoogle Scholar
  14. 14.
    Jauniaux E, et al. (2018) FIGO consensus guidelines on placenta accreta spectrum disorders: Introduction. Int J Gynaecol Obstet 140(3):261–264CrossRefGoogle Scholar
  15. 15.
    Jauniaux E, et al. (2018) FIGO consensus guidelines on placenta accreta spectrum disorders: Prenatal diagnosis and screening. Int J Gynaecol Obstet 140(3):274–280CrossRefGoogle Scholar
  16. 16.
    D’Antonio F, Iacovella C, Bhide A (2013) Prenatal identification of invasive placentation using ultrasound: systematic review and meta-analysis. Ultrasound Obstet Gynecol 42(5):509–517CrossRefGoogle Scholar
  17. 17.
    Budorick NE, et al. (2017) Another look at ultrasound and magnetic resonance imaging for diagnosis of placenta accreta. J Matern Fetal Neonatal Med 30(20):2422–2427CrossRefGoogle Scholar
  18. 18.
    D’Antonio F, et al. (2014) Prenatal identification of invasive placentation using magnetic resonance imaging: systematic review and meta-analysis. Ultrasound Obstet Gynecol 44(1):8–16CrossRefGoogle Scholar
  19. 19.
    McLean LA, et al. (2011) Assessing the role of magnetic resonance imaging in the management of gravid patients at risk for placenta accreta. Acad Radiol 18(9):1175–1180CrossRefGoogle Scholar
  20. 20.
    Meng X, Xie L, Song W (2013) Comparing the diagnostic value of ultrasound and magnetic resonance imaging for placenta accreta: a systematic review and meta-analysis. Ultrasound Med Biol 39(11):1958–1965CrossRefGoogle Scholar
  21. 21.
    Palacios-Jaraquemada JM, Bruno CH, Martin E (2013) MRI in the diagnosis and surgical management of abnormal placentation. Acta Obstet Gynecol Scand 92(4):392–397CrossRefGoogle Scholar
  22. 22.
    Ueno Y, et al. (2014) Novel MRI finding for diagnosis of invasive placenta praevia: evaluation of findings for 65 patients using clinical and histopathological correlations. Eur Radiol 24(4):881–888CrossRefGoogle Scholar
  23. 23.
    Bourgioti C, et al. (2018) MRI Features Predictive of Invasive Placenta With Extrauterine Spread in High-Risk Gravid Patients: A Prospective Evaluation. AJR Am J Roentgenol 211(3):701–711CrossRefGoogle Scholar
  24. 24.
    Chen, X., et al., Invasive placenta previa: Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta. Eur Radiol, 2018. 28(2): p. 708–717.Google Scholar
  25. 25.
    Sentilhes L, et al. (2018) FIGO consensus guidelines on placenta accreta spectrum disorders: Conservative management. Int J Gynaecol Obstet 140(3):291–298CrossRefGoogle Scholar
  26. 26.
    Chantraine F, et al. (2013) Prenatal diagnosis of abnormally invasive placenta reduces maternal peripartum hemorrhage and morbidity. Acta Obstet Gynecol Scand 92(4):439–444CrossRefGoogle Scholar
  27. 27.
    Eller AG, et al. (2011) Maternal morbidity in cases of placenta accreta managed by a multidisciplinary care team compared with standard obstetric care. Obstet Gynecol 117(2 Pt 1):331–337CrossRefGoogle Scholar
  28. 28.
    Shamshirsaz, A.A., et al., Maternal morbidity in patients with morbidly adherent placenta treated with and without a standardized multidisciplinary approach. Am J Obstet Gynecol, 2015. 212(2): p. 218 e1-9.Google Scholar
  29. 29.
    Silver RM, et al. (2015) Center of excellence for placenta accreta. Am J Obstet Gynecol 212(5):561–568CrossRefGoogle Scholar
  30. 30.
    Pettit, K.E., et al., Maternal and neonatal outcomes among scheduled versus unscheduled deliveries in women with prenatally diagnosed, pathologically proven placenta accreta. J Matern Fetal Neonatal Med, 2017: p. 1–5.Google Scholar
  31. 31.
    Jauniaux E, et al. (2016) Accreta placentation: a systematic review of prenatal ultrasound imaging and grading of villous invasiveness. Am J Obstet Gynecol 215(6):712–721CrossRefGoogle Scholar
  32. 32.
    Rac, M.W., et al., Ultrasound predictors of placental invasion: the Placenta Accreta Index. Am J Obstet Gynecol, 2015. 212(3): p. 343 e1-7.Google Scholar
  33. 33.
    Weiniger CF, et al. (2013) Outcomes of prospectively-collected consecutive cases of antenatal-suspected placenta accreta. Int J Obstet Anesth 22(4):273–279CrossRefGoogle Scholar
  34. 34.
    Matsuo K, Conturie CL, Lee RH (2014) Snowman sign: a possible predictor of catastrophic abnormal placentation. Eur J Obstet Gynecol Reprod Biol 181:341–342CrossRefGoogle Scholar
  35. 35.
    Horowitz JM, et al. (2015) When Timing Is Everything: Are Placental MRI Examinations Performed Before 24 Weeks’ Gestational Age Reliable? AJR Am J Roentgenol 205(3):685–692CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Priyanka Jha
    • 1
    Email author
  • Joseph Rabban
    • 2
  • Lee-may Chen
    • 3
  • Ruth B. Goldstein
    • 1
  • Stefanie Weinstein
    • 1
  • Tara A. Morgan
    • 1
  • Dorothy Shum
    • 1
  • Nancy Hills
    • 4
  • Michael A. Ohliger
    • 1
  • Liina Poder
    • 1
  1. 1.Department of Radiology and Biomedical ImagingUniversity of California San FranciscoSan FranciscoUSA
  2. 2.Department of PathologyUniversity of California San FranciscoSan FranciscoUSA
  3. 3.Department of Obstetrics and GynecologyUniversity of California San FranciscoSan FranciscoUSA
  4. 4.Department of Epidemiology and BiostatisticsUniversity of California San FranciscoSan FranciscoUSA

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