Power Doppler ultrasonography-directed prostate biopsy in men with elevated serum PSA levels: an evaluation of the clinical utility and limitations

Abstract

Objectives. To determine the utility and limitations of power Doppler ultrasonography (PDU)-directed prostate biopsy in patients with elevated serum prostate-specific antigen (PSA) levels. Methods. A total of 108 men (mean age 67.7 years, range 50 to 86) with serum PSA levels of greater than 4.0 ng/mL were assessed using digital rectal examination (DRE), gray-scale transrectal ultrasonography (TRUS), and PDU. Prostate vasculature identified on PDU was judged using a grading system. Subsequently, these patients underwent systematic six-core transperineal biopsy and additional biopsies for positive sites on DRE, gray-scale TRUS, and PDU. Results. A hypervascular site and prostate cancer on PDU was identified in 43 (40%) and 40 (37%) cases, respectively. PDU-directed and systematic six-core biopsies could independently detect 36 and 30 cancer cases, respectively. The sensitivity of PDU for cancer detection was 90%, specificity 90%, positive predictive value 84%, negative predictive value 94%, and accuracy 90%. High test performance was also observed in 53 cases with serum PSA levels of 4.1 to 10 ng/mL (sensitivity 77%, specificity 88%, positive predictive value 67%, negative predictive value 92%, and accuracy 85%). These values were superior or comparable to those of DRE and gray-scale TRUS. Inflammatory reactions and prostatic calculi were probable major causes of false-positive and false-negative results on PDU, respectively. Conclusions. PDU can identify appropriate sites for biopsy and improve the cancer detection rate. However, PDU-directed biopsy does not appear to identify prostate cancer with sufficient accuracy to omit the systematic biopsy, and combined use of these methods should be preferable.