Evaluation of transrectal power-Doppler ultrasonography and effect of contrast-enhancement for detecting prostate cancer

Abstract

There are many reports about the usefulness of transrectal power-Doppler ultrasonography (PDUS) for detecting prostate cancer because of the high microvessel density in cancerous tissue in the prostate. The purpose of this study was to assess the role of PDUS and contrast-enhanced transrectal power-Doppler ultrasonography (enhanced PDUS) in the identification of prostate cancer. One hundred forty-two cases (90 cases without enhancement, 52 cases with enhancement) of suspected prostate cancer found with digital rectal examination (DRE), transrectal ultrasound (TRUS) abnormal or prostate specific antigen (PSA) elevation were evaluated by PDUS and enhanced PDUS. Forty-three (30.3%) cases of cancer were detected, and there was a significant difference (p < 0.05) between PDUS group (22 cases, 24.4%) and enhanced PDUS (21 cases, 40.0%). However, there were no significant statistical results about the usefulness of enhancement to detect prostate cancer although imaging was clear with contrast agent. The results of statistical analysis of PDUS use were almost the same as for PSA of more than 10.1 ng/ml. Combination with PDUS was very helpful to detect prostate cancers. The positive predictive value of the combination with DRE, TRUS and PSA improved from 68.0% to 81.0% with the addition of PDUS. In particular, cancer was revealed frequently (65.8%) in peripheral hypoechoic lesions on gray-scale TRUS with hypervascular areas on PDUS. We conclude that enhancement with contrast agent is not especially useful in the identification of prostate cancer although imaging was clear with contrast agent. However, PDUS is useful especially for hypoechoic peripheral areas. It is suggested that we should add PDUS to DRE, TRUS and PSA examinations.