MRI can be useful for additional problem-solving of placental problems after ultrasound examination, including abnormal placental implantation.

IV contrast is not needed for evaluation (in fact, it is contraindicated). Instead, six key sequences are needed:

• triplanar balanced steady state free precession sequences (bSSFSP)
• triplanar T2 single shot fast spine echo sequences (SSFSE or HASTE)

Some institutions add a T1 fat sat axial sequence as well.

The goal of these sequences is to provide the best tradeoff of spatial and contrast resolution of the placental-myometrial interface.

Usually, a fetal MRI is ordered to evaluate the fetus rather than the placenta, but the placenta signal, shape, and attachment should still be commented upon.

For more information, see placental evaluation with MRI.