Correlation of transrectal ultrasound, computer analysis of transrectal ultrasound and histopathology of radical prostatectomy specimen

Abstract

A system for computerised analysis of ultrasonographic prostate images (AUDEX=Automated Urologic Diagnostic EXpert system) for the detection of prostate carcinoma was developed. The ultimate goal is to develop a system that is reliable and non-observer dependent. Results of an earlier study with a small group were encouraging and this study describes the results of the computerised analysis in a larger group. Sixty-two patients who were scheduled to undergo a radical prostatectomy were prospectively analysed. The radical prostatectomy specimens were step-sectioned in the transverse plane, corresponding to the ultrasound pictures. Malignant regions identified by each study were quantified and compared by computer calculation. No correlation was observed between ultrasound analysis and pathology result. For the AUDEX analysis an overall sensitivity of 85% and a specificity of 18% with only a diagnostic accuracy of 57% was noticed when presence or absence of malignancy was evaluated by octant (total 496). When applying a cut-off value of 0.5 ml the numbers were 71%, 33% and 55%, respectively. Correlation was significantly better for the ventral octants. In this study the earlier results of our AUDEX system could not be confirmed. Although sensitivity was good, specificity and especially diagnostic accuracy were lower than expected. We have to conclude that the current settings are inappropriate for routine clinical use.