[Color Doppler echography in the tissue characterization of renal masses]

To investigate color-Doppler US capabilities in tissue characterization, 42 renal masses were studied from November, 1993, to July, 1994. B-mode morphologic patterns were studied first and then integrated with color flow patterns; color areas and blood flow distribution were assessed for each lesion. Color signals were used as a guide to obtain arterial and venous Doppler spectra and to calculate flow velocities and pulsatility index (PI). Based on the us morphologic appearance, the 42 lesions were divided into 3 groups: A) lesions with morphologic and volumetric patterns of malignancy; B) small lesions (< 3 cm, > 3 cm < 5 cm); C) complex cysts. Data were organized and analyzed statistically; some findings were found to be typical of malignancy: hypervascularity, intralesional arterial signals with high flow velocities (systolic peak cut-off: 0.3-0.4 m/sec), high PI values (> 1) and, finally, color signals inside complex cysts. Our results suggest that color-Doppler US is a useful tool to assess renal masses vascularity, with the color-Doppler technique increasing US diagnostic accuracy. Nevertheless, small lesions need more careful study because their features are poorly demonstrated even with CT and MRI.