Figure 18a. Placenta percreta in a 31-year-old woman with a history of two cesarean sections. At 28 weeks gestation, the patient was referred for evaluation of a placenta that appeared abnormal at US. Coronal T2-weighted images (a obtained posterior to b) show disruption of the normally continuous low-signal-intensity bladder dome (arrow), an appearance consistent with placenta percreta. The obstetrician was notified before cesarean section about the likelihood of placenta percreta, although the exact longitudinal extent of invasion was uncertain before surgery. During surgery, placental invasion of the midline bladder was confirmed and resulted in extensive cystotomy.