The usefulness of power Doppler ultrasonography for diagnosing prostate cancer: histological correlation of each biopsy site

OBJECTIVE: To correlate the findings of power Doppler ultrasonography (PDUS) of the prostate with those of site-specific transrectal ultrasonography (TRUS)-guided biopsy. PATIENTS AND METHODS: The study comprised 28 patients referred to our institution for TRUS-guided prostate biopsy because of an elevated PSA level and/or abnormal digital rectal examination. PDUS findings were graded 0, 1 or 2; grades 0-1 were considered as negative and grade 2 as positive. The blood volume of each biopsy site was also determined using the mean number (MN) value that represents the average vascularity in a 5-mm square sample. PDUS values were correlated with the histological findings of 147 biopsies with 19 focal lesions. RESULTS: Grade 2 was assigned to 19 sites, grade 1 to 52 sites, and grade 0 to 76 sites. Fourteen of the 19 PDUS findings of grade 2 sites revealed carcinoma and five were grade 1. Ten of 35 TRUS-positive sites were carcinomas, three benign prostatic hyperplasia (BPH) and 22 normal. The MN value for prostatic carcinoma was 4.33, for BPH 11.7 and for normal tissue 4.7. The overall sensitivity of PDUS was 74%, the specificity 96% and the positive predictive value 74%. CONCLUSIONS: Because TRUS alone cannot detect all cancers, PDUS should be used routinely in all patients undergoing TRUS-guided biopsy, to improve the diagnostic yield of prostate cancer.