Evaluation of classic and novel ultrasound signs of placenta accreta spectrum.
Academic Article
Overview
abstract
OBJECTIVES: Improvements in the antenatal diagnosis of placenta accreta spectrum (PAS) would allow preparations for delivery in centers of excellence, leading to decreased maternal mortality and severe morbidity. Our objectives were to assess the performance of classic ultrasound signs and to determine the value of novel signs in the detection of PAS. METHODS: Cases of second trimester placenta previa who also had third trimester vaginal ultrasound, and all cases of PAS, at seven medical centers had outcome-blinded retrospective image review for signs of PAS by three MFM physicians. Classic signs of PAS were defined as placental lacunae, bladder wall interruption, myometrial thinning, and subplacental hypervascularity. Novel signs were defined as small placental lacunae, irregular placental myometrial interface (PMI), vascular PMI, non-tapered placental edge, and placental bladder bulge. PAS was diagnosed by difficulty in removing the placenta or placental pathologic confirmation. Multivariate regression analyses were performed, and ROC curves generated. RESULTS: A total of 55 cases of PAS were included (28 accreta, 11 increta, 16 percreta) The area under the curve and 95% CI for classic markers, novel markers and a model combining both were 0.82 (95% CI 0.75-0.88), 0.84 (95% CI 0.77-0.90) and 0.88 (95% CI 0.82-0.94) respectively. A model combining classic and novel signs was better than either model alone (p=0.03). An increasing number of signs was associated with greater likelihood of PAS. With the presence of 0, 1, 2, and >3 classic ultrasound signs, PAS was present in 5%, 24%, 57%, and 94% of cases respectively. CONCLUSIONS: We confirmed the value of classic ultrasound signs of PAS. The addition of novel ultrasound signs improves detection of PAS. These findings have clinical implications for the detection of PAS, and may help guide the obstetrical management of patients diagnosed with these placental disorders. This article is protected by copyright. All rights reserved.
