Efficacy of contrast-enhanced ultrasound for diagnosis of cesarean scar pregnancy type

Objectives: We compared the clinical efficacy of contrast-enhanced ultrasound (CEUS) to transvaginal ultrasound (TVS) for diagnosing cesarean scar pregnancy (CSP). Methods: A total of 485 cases of suspected CSP were recruited from January 2017 to March 2018. All received TVS and CEUS by two sonologists blinded to diagnosis by the other. Diagnostic features of CSP that significantly differed between modalities by univariate analysis (P<.05) were included in a logistic regression model. The sensitivity, specificity, positive likelihood ratio (+LR), negative likelihood ratio (-LR), and accuracy (ACC) of CSP diagnosis by TVS and CEUS were compared according to operational and pathological outcomes as the reference standard. Results: There were 220 CSP cases (including 85 cases of type I, 93 of type II, and 42 of type III). The sensitivities of CEUS for detection of types I-III CSP were 94.1%, 92.5%, and 97.6%, respectively, and corresponding sensitivities of TVS were 82.4%, 80.6%, and 95.2%. Compared to TVS, CEUS yielded significantly better overall sensitivity (97.27% vs 88.18%), specificity (96.60% vs 75.47%), +LR (28.60 vs 3.59), -LR (0.03 vs 0.16), and diagnostic ACC (96.9% vs 81.23%) (all P<.001). Conclusions: CEUS is superior to TVS for detecting cesarean scar pregnancy and distinguishing among CSP types.