Analysis of the blood flow of solid ovarian tumours using power Doppler ultrasound:: A new method to predict malignancies?

Objective: Power Doppler ultrasound can detect small blood vessels and slow blood velocities in solid tumours. Analysis of this micro-circulation may help to predict malignancies and the need for surgical intervention. Methods: We examined 48 unselected patients presenting with solid ovarian tumours. Following a routine transvaginal scan, blood flow was recorded from the whole tumour with instrument settings remaining the same during every examination. Power Doppler signals from a sequence of at least 20 seconds (or 100 frames) were stored on a digital video recorder. Artefact-free sequences were transferred to a Linux workstation and 3-D diagrams were calculated to display the intensities (numbers of erythrocytes or "back scatter") on the x-axis, the frequencies of intensities on the y-axis, and the time (seconds) on the z-axis. In addition, we calculated the mean of intensities for each tumour. Results: All patients underwent laparotomy. Histological examination identified 34 tumours as malignancies and 14 as benign; of these, six were tubo-ovarian abscesses. Benign tumours (n = 8) showed only low intensities (dark red pixels representing small blood vessels and slow velocities); inflammatory tumours and malignancies showed pixels of all intensities (yellow pixels presenting larger vessels and higher velocities). There was a significant difference in the mean intensity of non-inflammatory, benign tumours and that of inflammatory or malignant findings. Conclusions: After exclusion of inflammatory disease, power Doppler analysis of the blood flow of solid ovarian tumours can significantly predict malignancies. Power Doppler sonography may be helpful in differentiating between benign and malignant ovarian masses and can probably prevent unnecessary operative treatment.