2020 April Fools' Case: Normally we'd prank you with this but given the current COVID-19 crisis we decided just to release it straight up without trying to trick anyone. Hopefully you can at least still enjoy a little laugh at this difficult time - view case

Placental evaluation with MRI

Placental evaluation with MRI is a problem-solving technique that can be used if ultrasound evaluation is insufficient or confusing. Even if the placenta is not the main point of evaluation, it is useful to understand the appearance of the placenta on obstetric imaging for other causes.

Placental evaluation with MRI is not generally performed in the first trimester due to a theoretical risk of MRI to the embryo. 

Placental evaluation relies on two main sequences (acquired in all three planes):

  • single-shot fast spin echo (SSFSE)
    • or half-acquisition turbo spin echo (HASTE)
  • balanced steady state free procession (bSSFP) 

Additional planes may be useful for evaluation, as needed.

An axial T1 fat-suppressed may be added to evaluate for blood products. Diffusion-weighted sequences have also been used by some to evaluate the placental-myometrial interface.

Intravenous gadolinium contrast is not generally used out of potential risk to the fetus.

The placenta is a 2-4 cm thick pancake-shaped structure attached to either the anterior or posterior uterine cavity.

The placenta's imaging appearance changes during gestation:

  • 19-23 weeks
    • T2: homogeneous signal intensity
  • 24-31 weeks
    • placenta becomes lobulated
    • septae appear between the placental lobules
    • T2: increasingly heterogeneous signal intensity

An abnormal appearance of the placental implantation relies on disruption of the normal T2 trilayered appearance of gravid myometrium (central hyperintense vascular layer between two hypointense layers) 2. Abnormal placentation is not reliably assessed prior to 24 weeks gestational age 4.

Placental MRI can be very useful in confirming and characterizing of disorders of abnormal placental villous adherence:

Other situations in which it may be useful

  • abnormal placental location
  • delineating bilobed placenta or accessory placenta
  • placental vascular anomalies
  • mild placental lobulation and myometrial thinning can be seen in normal placental implantation
  • placental heterogeneity normally increases with gestational age
  • abnormal placental villous adherence should be confirmed in two planes
Share article

Article information

rID: 34317
System: Obstetrics
Synonyms or Alternate Spellings:
  • MRI of the placenta
  • Evaluation of the placenta with MRI

Support Radiopaedia and see fewer ads

Cases and figures

  • The green trace o...
    Case 1: sagittal to fetus
    Drag here to reorder.
  • The blue brackete...
    Case 1: sagittal to fetus
    Drag here to reorder.
  • Case 1: axial to fetus
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.