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PubMedDate not supplied

Ellipse test for the reduction of false positive signals in automated cytology.

One of the major problems in automated cytology is the elimination of false positive 'abnormal cell' alarms caused by objects such as overlapping cell pairs, leukocyte clusters, etc. The paper describes an algorithm for the separation of images of abnormal cell nuclei and non=nuclear objects in computer image analysis systems for automated cytology. The algorithm involves the measurement of the agreement between the object outline and a computer ellipse of equal area, aspect ratio and orientation. Results obtained with the CERVISCAN experimental computer image analysis system show that the algorithm gives good discrimination between abnormal cell nuclei and typical non-nuclear objects found in cervical scrape specimens prepared specially for automated analysis.

Cell Nucleus↗
PubMed1979

An automated microscope for quantitative cytology combining television image analysis and stage scanning microphotometry.

This paper describes an automated microscope developed for operation in conjunction with the Leyden Television Analysis System. It features automated control of magnification, illumination, movement of scanning stages, and fine focus. These functions are controlled by means of a microcomputer. This enables a flexible design and relieves the supervising computer of simple but time consuming tasks. The combination of an automated microscope and Leyden Television Analysis System provides a powerful tool in quantitative cytological research. The flexible design permits other microscopic functions to be added with relatively little effort.

Computers↗
PubMed1979

Cytomorphologic results of preparation experiments for monolayer deposition of cervical material.

For automated prescreening methods by high resolution analysis serving as a detecting method in gynecologic mass screening programs a new monolayer deposition method of cervical material has been used. This method will be outlines briefly and the mode of evaluation as well as current cytomorphological findings will be presented. With regard to measurability of the slides prepared according to the new method a number of cytologic criteria were thought to be of particular importance. These criteria are delineated and compiled in a table. A form in which these criteria were listed was filled in by cytopathologists for each slide evaluated. When performing isolation and centrifugation procedures several new morphologic questions arose to the cytopathologist which can only partly be answered by now. If taking into account all criteria of evaluation it may be followed from the present experiences that slides of cervical material are much more suited for automated prescreening methods by high resolution analysis if prepared after isolation and centrifugation in macromolecular liquids than are conventional Papanicolaou smears or slides from suspensions with isolated cells that were not subjected to centrifugation procedures.

Cell Separation↗
PubMed1992

Computer-assisted pattern recognition model for the identification of slowly growing mycobacteria including Mycobacterium tuberculosis.

We present a computerized pattern recognition model used to speciate mycobacteria based on their restriction fragment length polymorphism (RFLP) banding patterns. DNA fragment migration distances were normalized to minimize lane-to-lane variability of band location both within and among gels through the inclusion of two internal size standards in each sample. The computer model used a library of normalized RFLP patterns derived from samples of known origin to create a probability matrix which was then used to classify the RFLP patterns from samples of unknown origin. The probability matrix contained the proportion of bands that fell within defined migration distance windows for each species in the library of reference samples. These proportions were then used to compute the likelihood that the banding pattern of an unknown sample corresponded to that of each species represented in the probability matrix. As a test of this process, we developed an automated, computer-assisted model for the identification of Mycobacterium species based on their normalized RFLP banding patterns. The probability matrix contained values for the M. tuberculosis complex, M. avium, M. intracellulare, M. kansasii and M. gordonae species. Thirty-nine independent strains of known origin, not included in the probability matrix, were used to test the accuracy of the method in classifying unknowns: 37 of 39 (94.9%) were classified correctly. An additional set of 16 strains of known origin representing species not included in the model were tested to gauge the robustness of the probability matrix. Every sample was correctly identified as an outlier, i.e. a member of a species not included in the original matrix.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA, Bacterial↗
PubMed1979

Rapid analysis of hematology image data: the ADC-500 preprocessor.

A sequential, pipeline processor (that we have named the ADC-500 preprocessor) has been developed which scene segments the three color image data from the ADC-500 optics one image element at a time, groups together image elements from each object in the scene and extracts features from each object. The processing occurs at television frame rates, requiring 16.7 msec to process the entire image. This speed was instrumental in allowing the ADC-500 automated differential analyzer to perform routine 500-cell differentials. The preprocessor also contains hardware which simplifies compilation of the three color histograms. The segmentation algorithms implemented in the preprocessor are multicolor extensions of the classical monochrome density histogram threshold method. For most cell image analysis tasks, a sequential pipeline processor of this type should be more economical and as fast or faster than a parallel processor.

Blood Cells↗
PubMedDate not supplied

Automated computer screening of chest radiographs for pneumoconiosis.

The results of two complementary approaches for performing diagnostic screening for the presence of coal workers' pneumoconiosis (CWP) from the routine posterior-anterior chest radiograph are presented. The first is a digital approach utilizing the measurement of image texture, while the second uses hybrid optical-digital methods involving the optical Fourier transform. Both approaches yield classification results comparable to experienced radiologists.

Coal Mining↗
PubMed1979

An image analysis system for cervical cytology automation using nuclear DNA content.

An experimental computer/image analysis system has been used to investigate cytology automation techniques based on nuclear DNA measurement and morphological artefact rejector tests. The system automatically measures and normalizes the integrated optical density of cell nuclei in specially prepared cervical cytology specimens, and selects any objects with abnormally high values for further analysis. These are then analyzed by morphological and densitometric tests designed to eliminate false positive signals caused by non-nuclear artefacts. The coordinates of the remaining abnormal nuclei are recorded so that they can subsequently be relocated and examined by a cytotechnician. Preliminary results are given showing the measurement accuracy of the system and the performance of the artefact rejection tests.

Cell Nucleus↗
PubMedDate not supplied

Automatic registration of multiple skin lesions by use of point pattern matching.

Computerized comparison of serial skin images is a potentially valuable tool for melanoma screening. In automating this process, matching or "registering" each lesion in a pair of images plays an important role in looking for clinically significant change. We have investigated three practical techniques--a point pattern correlation, a 2-point geometrical transformation, and a 3-point geometrical transformation--for their effectiveness in matching and identifying lesions in pairs of skin images. These techniques view the spots in each image as a point pattern to be matched from image to image. Each of these methods is shown to be quite effective as long as one or more known initial match points can be provided. Experiments performed by imaging actual patients under realistic conditions indicate that the 3-point transformation algorithm performs the best overall, achieving an average matching accuracy of 97%. The nature of these algorithms, their relative performance under a range of conditions, and possible methods for improving accuracies are discussed.

Algorithms↗
PubMed1992

Diagnosing periapical bone lesions on radiographs by means of texture analysis.

Trabecular pattern, the radiographic projection of trabecular bone, is a repeated structure that appears in a dental radiograph. Texture analysis, the computer image analysis of repeated patterns, is a technique that can be used to automate the diagnosis of periapical lesions with the detection of the absence of the texture that corresponds to the trabecular bone. The purpose of this study was to determine whether it is feasible to use texture analysis to identify the presence of the trabecular pattern in radiographs and to detect a periapical bone lesion based on a local absence of this pattern. Thirty-two mandibular periapical films, 16 with and 16 without periapical lesions, were used in this study. Texture analysis was carried out on the digital images of these radiographs. In the 16 films with lesions, they were all correctly identified, and no lesions were found in the 16 films without lesions. This result is based on the a prior knowledge of the user about the localization of the disease. Locating periapical regions without user interaction is a goal for future research.

Alveolar Process↗
PubMedDate not supplied

Improved detection and classification of arrhythmias in noise-corrupted electrocardiograms using contextual information within an expert system.

The authors are developing an expert-system electrocardiogram (ECG) arrhythmia detector (HOBBES) for automated, long-term rhythm analysis. HOBBES employs rules and procedures that emulate how human experts analyze ECGs. This paper describes methods that HOBBES employs for improving error detection and correction in processing noisy ECGs. During periods of clean data, HOBBES develops a knowledge base that describes typical beat shapes, typical interbeat intervals between beats of different types, and patterns of beat sequences that it has observed. During periods of noisy data, HOBBES applies the information learned from the clean data to reject artifact and classify beats. HOBBES was evaluated in a noise-stress test using 35 half-hour ECG records containing a mixture of supraventricular and ventricular ectopy in normal sinus rhythm. In comparison with a classical arrhythmia detector (ARISTOTLE), HOBBES increased the number of correctly classified beats and enhanced the rejection of artifact.

Arrhythmias, Cardiac↗
PubMed1992

The role of automated speech recognition in endoscopic data collection.

Speech recognition technology has developed substantially in the past half decade. Currently, large vocabulary, speaker independent, discrete recognizers are the state-of-the-art. This will change. Moderate sized, continuous recognition systems now exist in research settings. However, it is unlikely that such systems will be widely available until the mid to late 1990's. The accuracy rates of current speech recognition systems are high. Consequently, speech accuracy is not the current limiting aspect of using ASR. The limiting aspect of using ASR technology is the approach to integrating speech functionality into applications. One approach is to use ATNs as models of natural language to support both an input strategy and a text generation system. ATNs provide approaches to both syntactical correctness and semantic richness. This is an approach which plays to the strengths of the discrete nature of current speech technology and also provides a methodology for the capture and archiving of highly detailed information. The ATN approach avoids the natural language parsing problem created by a fully free form dictation interface. Evolving along with the underlying speech technology are standards in the definitions and criteria used in endoscopic practice. There are clear benefits from standards in this area. However, it is likely that this will also take several years and may never yield a universally accepted lexicon. Furthermore, there will be user interface barriers to surmount in any system attempting to use speech as an input modality. Because of the relatively large vocabularies used in medical discourse, the user interface will need to be carefully crafted.(ABSTRACT TRUNCATED AT 250 WORDS)

Data Collection↗
PubMed1979

Detection of suspicious cells and rejection of artefacts in cervical cytology using the Leyden Television Analysis System.

In slide based automation of cervical cytology the first stage of analysis involves finding possibly suspicious cells, or areas on the slide with these types of cells. By using a television based system such as the Leyden Television Analysis System (LEYTAS), a number of detection methods can be applied to rapidly screen a large number of fields automatically for suspicious cells. In this paper, results using a parameter based on increased nuclear DNA content of cells are given and a second detection method based on a chromatin pattern feature, called chromatin contrast, is discussed. Two blind trials on 41 positive and 22 negative cervical slides, using the Leyden Television Analysis System to detect suspicious cells with an increased nuclear DNA content, were promising. In 1 of the 41 positive cases no suspicious cells were found. In the negative specimens, suspicious cells were detected in 1 of 9 cases and 1 of 13 cases, with the two detection parameters investigated. These findings are discussed and some automatic artefact rejection procedures with preliminary results are given.

Cervix Uteri↗
PubMed1979

Differentiating exogenous psychiatric illness from schizophrenia.

Retaining an individual on psychiatric dispensary lists long after a single psychotic episode can result in unnecessary restriction of his or her social-vocational rights and responsibilities. This study demonstrates that an early clinical differention can be made between exogenous psychoses and progressive schizophrenia. The validity of the clinical differentiation was enhanced by demonstrating that a computer learning and pattern-recognition program was capable of using signs and symptoms recorded in the first psychotic episode to make a differential diagnosis that coincided closely with diagnoses made at a later date by clinicians aware of the subsequent clinical course. This kind of approach to standardized nosologic principles may expand the possibility for more appropriate application of psychotropic medications, psychotherapy, and somatic treatments, as well as more accurate social-vocational prognoses.

Acute Disease↗
PubMed1977

Pattern recognition II: Investigation of structure--activity relationships.

A simple form of pattern recognition is successfully used to classify a set of structurally diverse therapeutic agents. By using only organic structural information, the major pharmacological classes present were correctly identified and the pharmacologically unrelated compounds were separated out. One technique of factor analysis--principal component analysis--is shown to be readily adaptable in preprocessing the data. Simple graphical representation of the results enables their direct interpretation.

Chemistry, Pharmaceutical↗
PubMed1992

Ultraviolet laser-induced fluorescence of colonic tissue: basic biology and diagnostic potential.

Laser-induced fluorescence (LIF) of colonic tissue was examined both in vitro and in vivo to assess the ability of the technique to distinguish neoplastic from hyperplastic and normal tissue and to relate the LIF spectra to specific constituents of the colon. Spectra from 86 normal colonic sites, 35 hyperplastic polyps, 49 adenomatous polyps, and 7 adenocarcinomas were recorded both in vivo and in vitro. With 337-nm excitation, the fluorescence spectra all had peaks at 390 and 460 nm, believed to arise from collagen and NADH, and a minimum at 425 nm, consistent with absorption attributable to hemoglobin. The spectra of colonic tissue recorded both in vivo and in vitro are different, primarily in the NADH fluorescence component, which decays exponentially with time after resection. When normal colonic tissue is compared to hyperplastic or adenomatous polyps, the predominant changes in the fluorescence spectra are a decrease in collagen fluorescence and a slight increase in hemoglobin reabsorption. A multivariate linear regression (MVLR) analysis was used to distinguish neoplastic tissue from non-neoplastic tissue with a sensitivity, specificity, predictive value positive, and predictive value negative toward neoplastic tissue of 80%, 92%, 82%, and 91%, respectively. When the MVLR technique was used to distinguish neoplastic polyps from non-neoplastic polyps, values of 86%, 77%, 86%, and 77% respectively, were obtained. The data suggest that the LIF measurements sense changes in polyp morphology, rather than changes in fluorophores specific to polyps, and it is this change in morphology that leads indirectly to discrimination of polyps.

Adenocarcinoma↗
PubMedDate not supplied

Classification of tumour 1H NMR spectra by pattern recognition.

1H spectra of tumours or normal tissues, which include signals from all hydrogen-containing metabolites, are too complex for the human eye to interpret. We have studied 58 1H spectra from perchloric acid extracts of three normal tissues (liver, kidney and spleen) and five rat tumours (GH3 pituitary, fibrosarcoma, Morris Hepatomas 7777 and 9618a and Walker carcinosarcoma). Instead of editing them or quantifying individual metabolites, we have used statistical pattern recognition techniques to classify them into groups. This automatic, objective method differentiated spectra from normal and malignant rat tissue biopsies, and from different types of cancer. It seems likely that this technique can be applied to human tissues and thus used for cancer diagnosis.

Animals↗