Computer Analysis of Transrectal Ultrasound Images of Prostate for Detection of Carcinoma: Prospective Study in Radical Prostatectomy Specimens

Abstract

Purpose: The reliability and objectivity of computer assisted transrectal ultrasound are exam ined.M aterials and Methods: Pathological examination of radical prostatectomy specimens was compared prospectively to automated cancer detection in corresponding transrectal ultrasound im ages.Results: For automated cancer detection, a sensitivity of 0.75 and a specificity of 0.78 were obtained. Moreover, 74% of hum an interpretation of the percentage of malignancy in the analyzed im ages was equal to the actual calculated percentage (Pearson's product moment correla tion coefficient 0.85).Conclusions: Comparing these results to those obtained with normal transrectal ultrasound, autom ated analysis provides additional information in the interpretation of transrectal ultra sound images by color coding them in an objective manner according to the probability of malignancy.

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

“…7 A preliminary study was published on the correlation between the AUDEX predictions and the pathology reports of 12 patients who underwent radical retropubic prostatectomy for localised prostate carcinoma. 8 In this small group a sensitivity of 75% and a speci®city of 78% could be obtained for automated prostate cancer detection, comparable to the results obtained in the biopsy group, 81% and 77%, respectively. 6 We now report on a larger group in order to further assess the value of the AUDEX analysis.…”

“…In our previous study with 12 patients however these numbers were 95%, 30% and 79%, respectively. 8 When the small volumes (`10% malignant volume ratio or`0.5 ml) were eliminated the numbers are 71%, 33% and 55% in the present study compared to 75%, 78% and 74% in our previous study. 8 In the present study the sensitivity data are comparable but speci®city and particularly diagnostic accuracy however are apparently inferior.…”

“…(2) The original training set was based on biopsy data as was extensively described in our previous publications. 6,7 In spite of the fact that in our ®rst study the correlation between biopsy data and radical prostatectomy specimen was found to be quite good, 8 the inferior results of the present series may however still be related to the fact that the training set was based on biopsy data. (3) In our ®rst study on 12 patients the ratios were estimated whereas in the present group the tumours and tumour volumes were quantitatively assessed.…”

“…6,8 First order statistics use the grey scale value directly to describe the texture. Statistics of the second order use the dependencies in grey values that can be described in a so-called co-occurence matrix.…”

“…8 For each octant the volume of malignant tissue indicated by the pathologist, urologist and the computer was calculated and stored in a database for comparison. Also the overall tumour volume for each technique was calculated.…”