Abstract【Objective】To investigate the contrast enhanced ultrasound(CEUS) features of complex pelvic masses undetermined by baseline-ultrasound. 【Methods】CEUS was performed on 137 patients with pelvic masses. The observation items included initial enhancement time

enhancement level and pattern

and the enhancement mode. 【Results】The enhancement pattern was different between the benign and malignant pelvic masses. Hyper-enhancement with earlier initial enhancement in comparison with the myometrium were found in 85.3% of pelvic malignant masses and 13.7% of benign masses (p＜0.05)

The inhomogeneous enhancement patterns were observed in 97.1% of malignant masses and 31.0% of benign masses (p＜0.05)

The enhancement mode I: hyper or iso-enhanced in early phase with a quickly wash-out within 40S in late phase

was observed in 85.3% of the malignant and 9.7% of benign masses (p＜0.05)

respectively. 【Conclusion】The enhancement of the pelvic masses is characteristic

which may be helpful for the characterization of the entity.