Kinetics of a US contrast agent in benign and malignant adnexal tumors

PURPOSE: To evaluate the effects of a microbubble contrast agent on the power Doppler ultrasonographic (US) examination of adnexal tumors, with a special focus on the timing of the transit of the microbubble bolus. MATERIALS AND METHODS: Seventy patients who were suspected of having ovarian tumors were examined preoperatively with contrast material-enhanced US. Images obtained during a 5-minute examination were stored digitally, and the behavior of the contrast agent was evaluated objectively with measurement of the time-dependent image intensity at the region of interest with a computer program. A time-intensity curve in each case was derived and analyzed. The Mann-Whitney U test was used to compare intensity changes and tumor parameters in benign and malignant adnexal tumors. RESULTS: Both the baseline and maximum power Doppler intensities, as well as the absolute and relative (percent) rise in intensity, were significantly higher (P <.001) in malignant as compared with benign tumors. The arrival time was shorter (17.5 vs 22.5 seconds; P =.005) and the duration of contrast agent effect was longer (190.4 vs 103.6 seconds; P <.001) in malignant tumors than they were in benign tumors. The area under the time-intensity curve was significantly greater in malignant tumors compared with that in benign tumors (P <.001). CONCLUSION: After microbubble contrast agent injection, malignant and benign adnexal lesions behave differently in degree, onset, and duration of Doppler US enhancement.