Counting mitoses by image processing in Feulgen stained breast cancer sections: the influence of resolution.

Counting of mitotic cells has been shown to be of prognostic value in breast cancer in different retrospective studies. Up to now the number of mitoses is assessed mainly manually according to a standardized but strict protocol. Although such a manual procedure is reasonably reproducible, automatic counting of mitotic cells offers the potential for greater objectivity and reproducibility. This paper describes the influence of resolution on automatic recognition by image processing of mitotic cells in Feulgen stained breast cancer sections. Using the image recording, correction and segmentation procedure described in a previous study, five specimens were analyzed: one was used to serve as a training set and four were put aside for later use as independent test set. For each slide, objects from a pre-selected area were recorded at increasing resolution. For each object, contour features and optical density measurements were computed and stored in a data file for statistical analysis. The results showed that increased resolution using a 40x objective lowered the number of misclassified mitoses compared with a 20x objective (overall mean percentage of misclassified mitoses over training and all test specimens: 20x, 24.57; 40x, 7.96). The number of misclassifications of non-mitoses was almost stable per specimen but varied between specimens (19-42%) due to differences among tissues. Given the improvement in classifying mitoses and the possibility to evaluate interactively the measurement result, the described semi-automated mitoses pre-screener of histological sections may be suitable for further testing in a clinical setting.

Quantitative microscopical and confocal laser scanning microscopy for intermediate endpoint biomarkers in breast cancer: potential and reproducibility.

Diagnostic quantitative pathological (QP) determinations are increasingly used in our hospital. The number of requests for QP for reference materials is rising rapidly. This is understandable; quantitative assessments have a strong prognostic value and can be very reproducible, depending on the care taken with a number of factors including cell and tissue processing, application of the appropriate stains, and the measurement protocol used. As to the latter, systematic random sampling gives the best intra- and interobserver agreement (with correlation coefficients between observers for certain features > or = 0.94). Flow cytometric determinations are often regarded as more reproducible than interactive morphometry due to the high speed of the assessments, the large number of objects measured per specimen, and the lack of observer interaction. Indeed, flow cytometrically assessed DNA ploidy is very reproducible, even though the % S-phase fraction is much more variable. Unlike image cytometry (ICM), visual inspection of cells is not easily accomplished with flow cytometry (FCM). With ICM, the fully automated measurement of DNA in thousands of cells is possible in 3-5 minutes, with a very low coefficient of variation (< or = 2% for the diploid and tetraploid peak of liver cell nuclei). ICM also allows measurement of texture features. However, quantitative immunohisto/cytochemical determinations may not always be as reproducible as sometimes believed. Recently, we found large variations in the measurements, made by a commercially available image processing instrument, of the estrogen and progesterone receptors, Ki-67, cathepsin D, and neu protein overexpression in breast cancer.(ABSTRACT TRUNCATED AT 250 WORDS)