Standardized endosonographic evaluation of prostate cancer: receiver-operator-characteristic analysis.

A standardized endosonographic numeric method has been developed for the detection of prostate cancer. Eighty-six men were examined with a 5-MHz, 96-element linear-array probe. Mean gray-scale amplitudes were produced by a semiautomatic method for periprostatic fat and regions of interest within the external portion of the prostate gland that were visually suspicious for prostate cancer. Mean gray-scale amplitude ratios of visually abnormal areas of prostate to periprostatic fat (Ap/Af) were calculated. Pathologic confirmation of disease was obtained in all patients. Three different numeric Ap/Af ratios were compared with digital palpation and subjective visual interpretation of sonograms. The numeric method resulted in a consistently higher specificity, accuracy, and positive predictive value when compared with palpation and subjective interpretation. The initial results suggest that this technique may also detect atypical hyperplasia.