EP16.31: Combination of transvaginal with transabdominal ultrasound for prenatal diagnosis of placenta accreta spectrum in differently experienced operators

To compare transabdominal ultrasound (TAS) alone and TAS plus transvaginal ultrasound (TVS) in diagnosing placenta accreta spectrum (PAS) with differently-experienced operators. The study included 70 pregnant women at high-risk of PAS with ultrasound and VDO clips which were independently reviewed by 2 obstetricians with ##> 5 and <5 years of experience in diagnosing PAS by ultrasound using the EW-AIP criteria. Both were blinded to the histories and final diagnoses of the intraoperative findings using the FIGO criteria and histopathology. The intra- and interobserver agreements of each ultrasound sign in TAS and TAS+TVS were assessed using kappa coefficients. Of the 70 cases, 14 (20%) were accreta, 22 (31.40%) increta, 19 (26.2%) percreta and 15 (21.4%) placenta previa, as diagnosed with the intraoperative FIGO criteria. The intraobserver agreements were moderate (kappa 0.41-0.60) in most signs, i.e. loss of clear zone and poor agreement (kappa < 0.4) for some signs, i.e. hypervascularity of cervix when compared between the preoperative TAS alone and with TVS added. The intraobserver agreements were slightly higher with the more experienced operator. The interobserver agreements were moderate to high (kappa 0.59-1.0) in each ultrasound sign for TAS and high agreement (kappa 0.83-1.0) for TAS plus TVS. The interobserver agreement for diagnosing PAS with TAS and TVS together was higher than for TAS alone, kappa 0.92 (95% CI 0.82-1.00) versus 0.67 (95% CI 0.47-0.87). The interobserver agreement for evaluating the severity of PAS with TAS plus TVS was higher compared to TAS alone, kappa 0.75 (95% CI 0.63-0.87) versus 0.51 (95% CI 0.36-0.66). The intraobserver and interobserver agreement to assess ultrasound signs to diagnose PAS was higher when TAS and TVS were combined compared to TAS alone. Also, the agreement of ultrasound sign assessments was higher for the more experienced operator when using TVS+TAS compared with TAS alone.