Development of a training program for the ultrasound screening of placenta accreta spectrum disorders

OBJECTIVE: To evaluate the impact of a training program using a systematic protocol on ultrasound signs of placenta accreta spectrum (PAS). METHODS: Intra- and inter-observer variability rates and sensitivity were tested, before and after additional training, by two research fellows with a prior basic training in obstetric ultrasound using digitally recorded second-trimester ultrasound images from cases of anterior placenta previa with and without PAS. RESULTS: Fifty-two cases of anterior placenta previa with PAS (n=26) and without PAS (n=26) were included in the study. The highest level of inter-observer agreement for ultrasound signs was found for the absence of placental bulge and/or focal exophytic mass on gray-scale imaging and the absence of subplacental hypervascularity, bridging vessels and lacunar feeder vessels on color Doppler imaging. The level of inter-observer agreement increased from 39% before training to 40% after training; the numbers agreed as PAS by both trainees increased from four to 20. No cases were classified as inconclusive after training. There was a significant (P<0.001) change in sensitivity for both trainees after training. CONCLUSION: Additional training in detecting the ultrasound signs associated with PAS using a standardized protocol improves the diagnostic accuracy of operators with only a basic obstetric ultrasound training.