Peripheral Zone Hypoechoic Lesions of the Prostate

Abstract

The purpose of this study was to evaluate the efficacy of contrast-enhanced gray scale transrectal ultrasonography (TRUS) for detection of prostate cancer in peripheral zone hypoechoic lesions of the prostate. The study involved 66 patients with peripheral zone hypoechoic lesions detected by TRUS. The lesions were evaluated with contrast-enhanced TRUS to differentiate prostate cancer from benign lesions, and the results were compared with color Doppler ultrasonographic findings. Transrectal ultrasonographically guided biopsy of the hypoechoic lesions revealed prostate cancer in 30 patients and benign prostatic diseases in 36. Flow signals within the lesions were classified as no, increased, equal, and decreased flow compared with surrounding peripheral zone tissue as follows: 1, 16, 12, and 1, respectively, in the prostate cancer group and 10, 12, 10, and 4 in the benign disease group. If we considered an increased flow signal within a peripheral hypoechoic lesion as a sign of prostate cancer, color Doppler ultrasonography had low sensitivity and specificity (55.2% and 53.8%, respectively). The enhancement intensity within the lesions was classified as no, increased, equal, and decreased enhancement compared with surrounding peripheral zone tissue as follows: 2, 20, 3, and 5 in the prostate cancer group and 14, 8, 4, and 10 in the benign disease group. The difference was statistically significant (P<.05). Thus, the peak enhancement intensity would be the optimal parameter for discriminatory performance (area under the receiver operating characteristic curve, 0.74; 95% confidence interval, 0.60-0.88). Contrast-enhanced TRUS could reveal the presence of vasculature within peripheral zone hypoechoic lesions more objectively than color Doppler ultrasonography and could be promising in guidance of prostate biopsy.