A 32-year-old G3P2 with two previous uterine surgeries undergoes ultrasound at 18 weeks. The placenta is anterior, covering the internal os, with loss of the retroplacental clear zone and multiple vascular lacunae. The most appropriate next investigation to evaluate depth of invasion is:

• A Color Doppler ultrasound of the placental bed
• B MRI pelvis with and without gadolinium ✓
• C Cystoscopy at 28 weeks
• D Serum AFP levels

Explanation

When ultrasound findings suggest placenta accreta spectrum (loss of retroplacental clear zone, vascular lacunae, previous cesarean with anterior low-lying placenta), MRI provides superior soft tissue contrast for assessing depth of myometrial invasion and lateral extension, especially for posterior placentas and percreta (bladder/parametrial involvement). MRI is complementary to Doppler ultrasound when ultrasound findings are equivocal or bladder involvement is suspected. Cystoscopy evaluates frank bladder involvement but cannot stage myometrial depth.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.