Table 2 Ultrasonographic criteria of the included studies

Overall estimate

Sensitivity

0.8703 (0.825—0.9051)

 < 0.001

Specificity

0.8634 (0.8142—0.9012)

 < 0.001

Correlation

-0.2348

Odds Ratio

34.225 (21.994—53.257)

 < 0.001

Negative Likelihood Ratio

0.155 (0.112—0.213)

 < 0.001

Positive Likelihood Ratio

4.990 (3.930—6.337)

 < 0.001

Myometrial thinning

Sensitivity

0.7627 (0.6249—0.8611)

 < 0.001

Specificity

0.8904 (0.7154—0.9633)

 < 0.001

Correlation

-0.4938

Odds Ratio

13.915 (4.920—39.356)

 < 0.001

Negative Likelihood Ratio

0.284 (0.149—0.543)

 < 0.001

Positive Likelihood Ratio

3.432 (2.039—5.777)

 < 0.001

Loss of retroplacental clear zone

Sensitivity

0.7799 (0.6905—0.8492)

 < 0.001

Specificity

0.8839 (0.7933—0.9379)

 < 0.001

Correlation

-0.1416

Odds Ratio

16.892 (7.908—36.082)

 < 0.001

Negative Likelihood Ratio

0.272 (0.188—0.394)

 < 0.001

Positive Likelihood Ratio

4.149 (2.703—6.369)

 < 0.001

Bridging vessels

Sensitivity

0.6593 (0.5418—0.76)

0.009

Specificity

0.9279 (0.7858—0.9783)

 < 0.001

Correlation

-0.5786

Odds Ratio

13.553 (5.520—33.277)

 < 0.001

Negative Likelihood Ratio

0.337 (0.154—0.739)

0.007

Positive Likelihood Ratio

3.489 (2.214—5.497)

 < 0.001

Placental lacunae

Sensitivity

0.7845 (0.7057—0.8468)

 < 0.001

Specificity

0.8086 (0.729—0.869)

 < 0.001

Correlation

-0.232

Odds Ratio

11.115 (6.826—18.096)

 < 0.001

Negative Likelihood Ratio

0.275 (0.198—0.382)

 < 0.001

Positive Likelihood Ratio

2.972 (2.288—3.860)

 < 0.001

Bladder wall interruption

Sensitivity

0.4551 (0.3262—0.5902)

0.482

Specificity

0.9747 (0.922—0.9921)

 < 0.001

Correlation

-0.2586

Odds Ratio

10.681 (3.393—33.622)

 < 0.001

Negative Likelihood Ratio

0.542 (0.362—0.811)

0.003

Positive Likelihood Ratio

4.965 (2.237—11.021)

 < 0.001

Exophytic mass

Sensitivity

0.2182 (0.1171—0.3702)

0.001

Specificity

0.8653 (0.3226—0.9886)

0.216

Correlation

0.7355

Odds Ratio

1.184 (0.104—13.528)

0.892

Negative Likelihood Ratio

1.551 (0.439—5.483)

0.496

Positive Likelihood Ratio

1.456 (0.318—6.663)

0.629

Uterovesical vascularity

Sensitivity

0.5135 (0.3051—0.7173)

0.845

Specificity

0.9937 (0.9104—0.9996)

 < 0.001

Correlation

-0.4241

Odds Ratio

12.778 (4.797—34.035)

 < 0.001

Negative Likelihood Ratio

0.438 (0.256—0.748)

0.003

Positive Likelihood Ratio

3.744 (2.074—6.759)

 < 0.001