A woman with a previous caesarean scar at 32 weeks has placenta praevia with suspected accreta spectrum. MRI is performed. Which MRI feature carries the highest specificity for placenta percreta (invasion through serosa)?
- A Loss of the dark T2 myometrial zone posterior to placenta
- B Uterine bulging with placental tissue signal extending beyond serosal surface ✓
- C Intraplacental T2 dark bands (lacunae)
- D Focal interruptions in the utero-vesical interface
Correct answer: B. Uterine bulging with placental tissue signal extending beyond serosal surface
Explanation
On MRI, direct visualization of placental tissue signal extending beyond the uterine serosal surface with uterine bulging is the most specific sign for percreta. Loss of the dark T2 myometrial zone indicates accreta/increta but is not specific for percreta. Intraplacental T2 dark bands (lacunae) are an early sensitive sign but less specific for depth of invasion. Focal interruptions in the utero-vesical interface suggest bladder invasion (a form of percreta) but is one component of percreta assessment.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.