3,650 research outputs found
Machine vision in the detection of prostate lesions in histologic sections
No full textOBJECTIVE: To explore the utility of N-gram encoding for the automated detection and delineation of regions of histologic abnormality in tissue sections of prostate.
STUDY DESIGN: Digitized imagery of tissue sections from normal prostate glandular tissue, stroma and regions of well- and poorly differentiated lesions was recorded and successively subdivided into square subregions of 256 x 256 to 16 x 16 pixels. N-grams of N = 2 to N = 6 were computed, with each element assuming a value representing an optical density interval 0.30 units wide, covering the range from optical density = 0.0 to 1.80. Then, from a large database, prototype frequency histograms of the different N-grams were established. For each subregion the Euclidean distances to the different prototype histograms were computed and defined as "distance to prototype" features. Standard discriminant analyses and a nonparametric classifier were used to assign subregions to the different tissue categories.
RESULTS: Classification of subregions was achieved for most discrimination tasks at a correct recognition rate ranging from 85% to 100% on both training set and test set data, with a few exceptions. N-grams of N > 4 had considerable discriminatory power.
CONCLUSION: N-gram encoding has the potential to provide highly discriminating, texture-based characterization of subregions of digitized imagery of prostate lesions and may be very useful in the development of decision procedures for the automated detection of prostate lesions by a machine vision system
Nuclear chromatin texture in prostatic lesions I. PIN and adenocarcinoma
No full textOBJECTIVE: To document changes in the chromatin pattern in secretory cell nuclei from prostates with prostatic intraepithelial neoplasia (PIN) or adenocarcinoma.
STUDY DESIGN: High-resolution images of nuclei were recorded, and a set of features descriptive of the chromatin texture and spatial distribution was computed. From this data set, features undergoing a monotonic trend of progression were selected and plotted to reveal trends in lesion progression.
RESULTS: The nuclear chromatin in secretory cells in prostates with either PIN or malignant adenocarcinoma undergoes distinct and statistically significant changes in its texture and spatial distribution. Two trends of progressive change were observed. First, the values of a number of features descriptive of the clumpiness of the chromatin increase from values found in normal prostates to those recorded for nuclei from low grade to high grade PIN lesions. The second trend is a decrease in the values of the same features from those found in nuclei from high grade PIN still facing an intact basal cell layer to those no longer facing such a layer. This may be the first detectable step in progression towards development of a malignant lesion. There is a further decrease in nuclei in glands immediately adjacent to adenocarcinoma and in malignant lesions themselves.
CONCLUSION: The described changes may lend themselves to the monitoring of lesion progression or of response to treatment or to chemopreventive intervention
Nuclear chromatin texture in prostatic lesions II. PIN and malignancy associated changes.
No full textOBJECTIVE: The objective of this study was to identify and document prostatic intraepithelial neoplasia (PIN) and malignancy associated changes in secretory cell nuclei from visually normal appearing tissue regions of prostates harboring PIN or adenocarcinoma.
STUDY DESIGN: High-resolution digitized images of nuclei were recorded in histologically normal appearing tissue regions at defined distances from the margin of PIN or malignant lesions. Features descriptive of nuclear chromatin texture were computed and used to derive a discriminant function score for each nucleus.
RESULTS: Secretory cell nuclei in prostates harboring either PIN or adenocarcinoma were shown to have statistically significantly different chromatin texture from secretory cell nuclei recorded in prostates free from any such lesion. The expression of PIN or malignancy associated changes was documented for distances up to 10 mm from the margin of a lesion.
CONCLUSION: The finding of characteristic changes in nuclear chromatin texture of nuclei from histologically normal appearing tissue in prostates with PIN or adenocarcinoma offers the potential for higher sensitivity of detection of such lesions and for earlier detection of changes potentially preceding the development of clinically significant disease
Machine Vision-based Histometry of Premalignant and Malignant Prostatic Lesions.
No full textThe implementation of knowledge-guided control of the processing and segmentation of histopathologic images of prostatic lesions has made automated analysis and interpretation possible. To establish correspondence between histopathologic concepts, terms and diagnostic criteria, and computed histometric entities, "interpretive transforms" are introduced. Scene segmentation is controlled by an expert system following a model-based reasoning process. The expert system is structured as an associative network with frames at each node, which controls a knowledge file and a large library of image processing algorithms
SEAFP: passive removal of the decay heat
No full textPassive safety is a key issue for the public acceptance of fusion power. Several studies are under way in the European Safety and Environmental Assessment of Fusion Power (SEAFP) program to analyze the possible hazards and the means to keep the system safe. The demonstration that the decay heat of the structural materials of the reactor will not cause the failure of the containment, even in the absence of any form of active cooling, is a significant contribution towards the demonstration of the passive safety of fusion
Atypical adenomatous hyperplasia (adenosis) of the prostate: Development of a Bayesian belief network for its distinction from well-differentiated adenocarcinoma
No full textTissue architecture analysis in prostate cancer and its precursors: An innovative approach to computerized histometry.
No full textAIMS: It is the aim of these studies to derive a numerically defined progression index for prostatic intraepithelial neoplasia (PIN) lesions.
METHODS: Histometric and karyometric features were automatically extracted from images of histopathologic sections by a machine vision system.
RESULTS: Both histometric and karyometric measures lend themselves to the defining of a progression index. Karyometric features were found to be more sensitive. They allow the detection of very early change.
CONCLUSIONS: It is possible to measure progression of PIN lesions with precision. The methodology would lend itself for measurement of regression due to chemopreventive intervention
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