Objective: We performed a prospective study to assess gray-scale and color and power Doppler sonography for the detection of prostatic cancer and to determine the impact of operator experience.
Subjects and methods: Four radiologists with prior experience using gray-scale and Doppler imaging and four urologists with prior experience limited to gray-scale imaging performed sextant biopsies on 251 patients. Each biopsy site was prospectively scored for gray-scale and Doppler abnormality.
Results: Cancer was detected in 211 biopsy sites from 85 patients. Overall agreement between sonographic findings and biopsy results as measured with the kappa statistic was minimally superior to chance (kappa = 0.12 for gray-scale, kappa = 0.11 for color Doppler, kappa < or =0.09 for power Doppler). With respect to gray-scale diagnosis of cancer, the performance of radiologists (kappa = 0.12) and urologists (kappa = 0.13) was similar. With respect to power Doppler, the performance of radiologists (kappa = 0.09) was superior to that of urologists (kappa = -0.03, p<0.002). Among patients with at least one positive biopsy for cancer, foci of increased power Doppler flow detected by a radiologist were 4.7 times more likely to contain cancer than adjacent tissues without flow.
Conclusion: Gray-scale and Doppler imaging did not reveal prostatic cancer with sufficient accuracy to avoid sextant biopsy. Power Doppler may be useful for targeted biopsies when the number of biopsy passes must be limited. There is benefit from increased operator experience with Doppler imaging, but there is no demonstrable benefit of power Doppler over conventional color Doppler sonography.