Usefulness of color Doppler flow imaging in differential diagnosis of multilocular cystic lesions of the kidney.

Color Doppler flow imaging was carried out in 10 multilocular cystic lesions of the kidney. These consisted of three renal cell carcinomas, three hemorrhagic renal cysts, one benign multilocular cystic nephroma, two infected renal cysts, and one benign multilocular renal cyst secondary to von Hippel-Lindau disease. In the patients with renal cell carcinoma, color signals were obtained at the septum and in the solid component within the lesions. A pulsatile wave with a large maximum flow velocity and a high PI value was obtained in two of them. In one of the patients with hemorrhagic renal cysts, color signals were obtained at the region of the septum. In the other benign lesions, however, color signals were obtained only at the peripheral margin, and the flow waveform in these cases was identical to the waveforms found in the interlobar arteries. This study suggested that color display in the lesion well reflects its vascularity in patients with multilocular cystic renal diseases and that measurement of the systolic maximum flow velocity by fast Fourier transform analysis is useful for the differential diagnosis of malignant versus benign lesions.