Contrast-enhanced ultrasound enhances diagnostic accuracy in tubal ectopic pregnancies: A comparative study with transvaginal sonography.

OBJECTIVE

This study aimed to compare the diagnostic accuracy of transvaginal sonography (TVS) versus contrast-enhanced ultrasound (CEUS) for ectopic tubal pregnancy (ETP), with a specific focus on low human chorionic gonadotropin (HCG) levels (<2000 U/L).

METHOD: A retrospective cohort analysis was conducted on 682 consecutive patients with clinically suspected ETP admitted to Beijing Shijitan Hospital from January 2015 to June 2024. Among these, 121 patients underwent dual-modality assessment (CEUS and TVS), while 561 received TVS alone. Diagnostic performance was evaluated through sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). Subgroup analysis stratified by HCG levels (<2000 U/L) was performed. Distinct CEUS imaging features of ETP were additionally characterized.

RESULTS

For TVS, the sensitivity and specificity for ETP diagnosis using composite criteria (Grade 1 + Grade 2) were 74.25% and 50%, respectively (AUC = 0.62). In contrast, CEUS demonstrated superior sensitivity (98.28%) and specificity (80%), with a significantly higher AUC (0.89 vs. 0.62, P < 0.001). In the HCG-stratified subgroup (<2000 U/L), TVS exhibited reduced sensitivity (64.97%) and marginal specificity improvement (53.85%, AUC = 0.594), whereas CEUS maintained robust sensitivity (97.5%) and specificity (80%, AUC = 0.88), significantly outperforming TVS (P < 0.001).

CONCLUSION

Contrast-enhanced ultrasound represents a highly accurate modality for ETP diagnosis, particularly in cases with HCG levels <2000 U/L. These findings support the utility of CEUS as a valuable diagnostic tool to complement conventional TVS in clinically ambiguous scenarios.