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At least 1,225 records · Page 68Linked to original sources
PubMed2001

Computer assisted image analysis methods for evaluation of periodontal wound healing.

The aims of this study were to determine the accuracy of the computer assisted image analysis method and to evaluate its application for the assessment of periodontal wound healing in dogs. Histological material was analyzed with an optic microscope connected to a CCD color camera which transmitted the image to a frame grabber converting the light signals into pixels from which the measurements could be obtained. Twenty sections were read to assess the intra- and inter-examiner reproducibility for the parameters of area filled by new tissue, area of epithelium, area of bone and linear measurements of the cementum. The data were statistically analyzed using the t-test to test the hypothesis that there was no difference between and within examiners. No statistically significant differences were noted (with a confidence interval of 95%) for any parameter when intra-examiner reproducibility was assessed. Similar results were achieved for surface areas when the inter-examiner readings were computed. However, values of linear measurements for cementum showed statistically significant differences between recorders (p < 0.05). Results were consistently uniform and the method demonstrated high accuracy when intra-examiner readings were evaluated.

Alveolar Process↗
PubMed1983

The use of hierarchic classification in the image analysis of a complex cell population. Experience with the sediment of voided urine.

Microscopic analysis of cells in the sediment of voided urine is the principal noninvasive method of diagnosing and detecting cancer of the lower urinary tract, mainly the bladder. The sediments contain several populations of cells of unequal diagnostic value. By applying a system of hierarchic classification to the computer analysis of digitized cell images, we were able to eliminate from diagnostic consideration cells that are difficult to classify, such as degenerated cells, multinucleated cells, cell clusters, renal tubular cells and cells infected by the human polyomavirus. When this method of triage was applied to the images of sequentially encountered epithelial cells and clusters, the cell images accepted for final analysis by the computer were sufficient in number and quality to automatically construct cytologic profiles of documented diagnostic value in 15 patients with bladder cancer. The method proved to be applicable to smears and quantitative cytocentrifuge preparations processed by methods developed in our laboratory. This work clearly documents the feasibility of automated analysis of cells in voided urine for the purpose of diagnosing bladder cancer. It also confirms prior observations suggesting that a relatively small sample of sequential images of epithelial cells (200 to 300) is sufficient to establish a diagnostic profile of clinical value on patients with high-grade cancer of the urinary bladder.

Computers↗
PubMed1997

Primary study of neovasculature correlating with metastatic nasopharyngeal carcinoma using computer image analysis.

The significance of neoangiogenesis in the metastasis of nasopharyngeal carcinoma (NPC) was investigated to clarify the role neovascularity in the prognosis of NPC and the probability of antiangiogenesis preventing NPC from distant metastasis. A group of 52 patients presenting with metastatic NPC were selected and strictly paired one-to-one, in sex, age, T stage, and N stage, with another 52 patients with non-metastatic NPC, who had survived for a long time after therapy. The tumor tissues of all 104 patients were retrieved for computer-assisted, immunohistochemical analysis of tumor vasculature. Counts of the microvessels and the relative area of all microvessels per image were significantly higher in metastatic NPC than they were in curable, non-metastatic NPC, while the average area of the microvessels and their average perimeter of in metastatic NPC were smaller than in non-metastatic disease. No significant difference in any microvessel parameter was found among the various types of metastasis. The alterations of microvessel parameters were significantly linked to the metastasis of NPC. Evaluation of neovascularity by computer image analysis may be helpful in estimating the prognosis of NPC and in determining the indicators for aggressive multimodal treatments.

Adult↗
PubMed1999

Measuring facial expressions by computer image analysis.

Facial expressions provide an important behavioral measure for the study of emotion, cognitive processes, and social interaction. The Facial Action Coding System (Ekman & Friesen, 1978) is an objective method for quantifying facial movement in terms of component actions. We applied computer image analysis to the problem of automatically detecting facial actions in sequences of images. Three approaches were compared: holistic spatial analysis, explicit measurement of features such as wrinkles, and estimation of motion flow fields. The three methods were combined in a hybrid system that classified six upper facial actions with 91% accuracy. The hybrid system outperformed human nonexperts on this task and performed as well as highly trained experts. An automated system would make facial expression measurement more widely accessible as a research tool in behavioral science and investigations of the neural substrates of emotion.

Adult↗
PubMed1991

Developmental gradients of vasoactive intestinal polypeptide (VIP)-containing neurons in the rat visual cortex detected by image analysis.

The postnatal development of vasoactive intestinal polypeptide-immunoreactive (VIP-IR) neurons was followed by computer-assisted image analysis in the rat visual cortex. The laminar distribution of all VIP-IR structures was measured. These structures were subdivided into cell somata, dendritic profiles and axonal boutons and measured separately. VIP-IR neurons were first seen on postnatal day 1, mostly in the upper half of the presumptive visual cortex. A localization of cell bodies similar to that in the adult is reached between days 12 and 16. VIP-IR dendrites have a protracted growth period as compared to perikarya, involving a developmental gradient from an even distribution to a concentration in the upper cortical layers. This is due to the formation of dendritic terminal arbors after the second postnatal week. Scattered VIP-IT axonal boutons appear on day 3 in the midportion of the presumptive visual cortex. Their typical laminar distribution in layers II, IV and lower VI was observed after day 12. Our results suggest that the biochemically detected sharp increase in VIP levels after the second postnatal week is due to the maturation of cell processes as a morphological basis of neuronal connectivity.

Aging↗
PubMed1990

Early detection of colorectal cancer by quantitative fluorescence image analysis of exfoliated cells.

Early-stage colorectal cancer is potentially curable. In the present study, we applied quantitative fluorescence image analysis (QFIA) cytology to the detection of experimental colorectal cancer in a rodent model. QFIA cytology combines visual cytologic examination with quantitation of DNA content in single exfoliated cells. Cancer was induced by treating 110 rats with subcutaneous 1,2-dimethylhydrazine. Sequential colon washes were obtained weekly from each animal for 20 weeks. Control animals were treated identically except for the administration of carcinogen. Cells that were cytologically abnormal or had increased DNA content were found starting in the second week. By the eighth week, roughly 50 percent of animals had positive results, and this level remained approximately constant for the duration of the study. Tissue pathologic results were normal during weeks 1 to 7. Dysplasias became common during weeks 8 to 15 whereas most cancers appeared during weeks 16 to 21. These results indicate that QFIA cytology is a highly sensitive method for detecting even preneoplastic changes resulting from carcinogen administration and may prove useful in detecting human colorectal cancer.

Animals↗
PubMed1982

Autoradiographic grain counting by fully automated image analysis.

A method for automated quantitative analysis of single label microautoradiographs applied to DNA repair synthesis is proposed. It uses image analysis of the microscopic field by a Leitz TAS and allows an automated selection of the nuclei to be analysed. The use of a grey level gradient algorithm provides a relatively large independence from external variables such as staining intensity, nuclei density in the field, stability of illumination etc. Random choice of the microscopic field by the computer directed stage displacement and automatic focusing ensures a high degree of objectivity and independence from human intervention. The coefficient of correlation between the automatic and the visual grain count is 0.97 in the range of visually countable grain densities, while the precision of measurement is about 10%. The speed of measurement is satisfactory (40 to 60 s for the analyse of a microscopic field) taking in account that only occasional supervision is needed.

Animals↗
PubMed1986

Semi-automatic image-analysis applied to the quantification of bone microstructure.

Bone microstructure can be quantified by methods ranging from simple manual techniques to fully automatic image analysis systems. We describe a semi-automatic method, developed in BASIC and running on a laboratory microcomputer. Its core is based on two special algorithms for image conversion and for calculation. These two algorithms produce quantifying characteristics for any irregularly shaped structure, as defined by one or more open or closed contour lines. The quantification of these structural parameters relies only on contour line digitization. The improved efficiency of this semi-automatic method is a consequence of combining automatic calculations and human assistance. The structural parameters chosen were for a specific research project; the correlation between mechanical and microstructural properties of cortical bone, but they may readily be changed as circumstances demand.

Biomechanical Phenomena↗
PubMedDate not supplied

Automated segmentation and visualization of the pulmonary vascular tree in spiral CT angiography: an anatomy-oriented approach based on three-dimensional image analysis.

A new method for automated segmentation of the pulmonary vascular tree in spiral CT angiography was developed based on 3D image analysis techniques and anatomic knowledge. For efficient and effective segmentation, an anatomy-oriented approach was introduced, in which several anatomic structures are segmented sequentially and the properties of each segmented structure are used for the next step of segmentation and for validation of intermediate results. By use of clinical data of 12 patients, parameters for segmentation were analyzed and optimized. The effectiveness of the segmentation method was evaluated through the visual assessment by comparison between images of the segmentation results by volume rendering and images of maximum intensity projection of the original volume data.

Angiography↗
PubMed1991

Regional and long-term variability of fundus measurements made with computer-image analysis.

We studied the variability of optic disk and peripapillary nerve fiber layer surface contour measurements made by use of computer-image analysis. Six hundred twenty-five measurements of surface contour were made on each eye by use of simultaneous stereoscopic videography. Regional differences in short-term measurement variability were studied in 12 eyes (six normal and six glaucomatous), each imaged nine times over several days. The widths of the 95% confidence interval for the measurements averaged 82 microns for the juxta-papillary surface and 132 microns for the disk surface. Measurements of peripapillary surface contour were significantly less variable than were measurements of the disk surface (P = .000). The greatest variability was detected along large blood vessels and at steep contours. Long-term variability was studied in a separate group of 30 clinically stable patients with glaucoma, each imaged three to six times over a period of more than one year. The widths of the 95% confidence intervals were 132 microns for the peripapillary surface and 217 microns for the disk surface. The long-term variability was significantly greater than the short-term variability (P = .000). The peripapillary nerve fiber layer surface, located away from the margins of large vessels, may provide the most dependable measurements of contour. These estimates of long-term variability of optic disk and peripapillary contour measurements provide clinically relevant confidence intervals with which to detect progressive glaucomatous nerve fiber damage.

Adult↗
PubMed1989

Analysis of machine-selected cells with an image analysis system in normal and abnormal cervical specimens.

An analysis has been performed of visual diagnostic criteria used in cervical cytology applied to machine selected cells in relation to automated classification based on variables, which can be recorded in an image system with automated cell search and segmentation, feature extraction and classification. A 98% accuracy could be obtained with the choice of the most ideal statistical methods for discrimination and the use of the most powerful variables recorded in the image system when compared with consensus of the visual diagnoses based on established cytological criteria for diagnosis of cancer and precancer of the cervix uteri. The most powerful discriminatory variables in the image system (of 17 recorded) for discrimination between normal and abnormal epithelial cells were, in addition to nuclear extinction, cytoplasmic extinction and cytoplasmic shape. It is concluded that the visual classification of cervical cells is highly accurate with experienced observers and that imaging microscopes can be trained to nearly equal this accuracy with appropriate statistical methods of discrimination. The problem of creating fully automated systems, however, also requires the inclusion of even more effective discriminatory variables and also the solution of such problems as automatic cell search, segmentation, artifact rejection, feature extraction, classification and electronic stability in order to become cost-effective.

Cervix Uteri↗
PubMed2003

Digital image analysis of cadaver mandibular trabecular bone patterns.

BACKGROUND: The purpose of this study was to investigate the source of radiographic trabecular patterns by removing trabecular bone in four sequential steps from six cadaver mandible sections, radiographing the sections after each removal, and using four digital-image analysis methods to quantify any resulting changes to the radiographs. METHODS: Mandible sections were cut sagittally into halves. Trabecular bone was removed from each section in four stages. Following each stage, standardized radiographs were taken, using direct digital equipment. Trabecular bone in the resulting digital images was measured with four methods. Mean gray level values (method 1) and cumulative percent histograms (method 2) were calculated from the raw data. Morphological image processing was used to skeletonize the trabecular structure, which was quantified by counting the number of trabecular ends and segments in the skeletonized images (method 3) and performing fractal analyses of the skeletonized images (method 4). Repeated measures analysis of variance (ANOVA) was used to test for changes in measurements attributable to bone removal. RESULTS: Repeated measures ANOVA indicated that the use of gray levels, cumulative percent histograms, and morphologic operators resulted in highly significant changes in measurements following bone removal (P < 0.01). Ends and segments demonstrated similar performance, with changes highly significant over time (P < 0.01). Fractal analysis also resulted in highly significant changes over time (P < 0.01). CONCLUSIONS: The analyses performed in this study demonstrated consistent image differences following the four steps of bone removal. These differences appeared whether light, cancellous bone or heavier endosteal bone was removed. These findings indicate that trabecular and endosteal bone combine to form the structure that most dentists identify as trabeculae on intraoral radiographs.

Analysis of Variance↗
PubMed1993

Quantitative image analysis of vertebral body architecture--improved diagnosis in osteoporosis based on high-resolution computed tomography.

71 women, 64 post-menopausal, were examined by single-energy quantitative computed tomography (SEQCT) and by high-resolution computed tomography (HRCT) scans through the middle of lumbar vertebral bodies. Computer-assisted image analysis of the high-resolution images assessed trabecular morphometry of the vertebral spongiosa texture. Texture parameters differed in women with and without age-reduced bone density, and in the former group also in patients with and without vertebral fractures. Discriminating parameters were the total number, diameter and variance of trabecular and intertrabecular spaces as well as the trabecular surface (p < 0.05)). A texture index based on these statistically selected morphometric parameters identified a subgroup of patients suffering from fractures due to abnormal spongiosal architecture but with a bone mineral content not indicative for increased fracture risk. The combination of osteodensitometric and trabecular morphometry improves the diagnosis of osteoporosis and may contribute to the prediction of individual fracture risk.

Adolescent↗
PubMed1991

Application of digital image analysis in dental radiography for the description of periapical bone lesions: a preliminary study.

This paper describes an application of digital image analysis for the description of periapical bone lesion in dental radiography. These techniques enable the problem of observer variability to be circumvented, and can eventually be used for the quantitative assessment of bone lesions. Since periapical bone lesions appear radiographically as dark areas compared with their surrounding tissues, an edge-detection method was developed to extract the boundaries between anatomy and pathology. The original data were transformed in such a way that only the outlines remained. The lesion was assumed to be demarcated by a continuous outline, so all the contour points not being part of a continuous outline were excluded. With only limited operator interaction, the lesion contour could be projected successfully onto the original image. The result of this operation was a simplified diagnostic examination process promising a higher degree of objectivity in periapical bone lesion detection. It is concluded that the results encourage further development of image processing techniques suitable for the definitive detection and diagnosis of periapical bone lesions.

Alveolar Bone Loss↗
PubMed1987

Increase of pallor and fluorescein-filling defects of the optic disc in the follow-up of ocular hypertensives measured by computerized image analysis.

In 24 ocular hypertensive patients, two optic disc fluorescein angiograms were obtained a mean of 3.9 years apart. Using computerized image analysis, we measured the area of pallor and the fluorescein-filling defect area within the disc and the fluorescein circulation parameters representing the filling rates of optic disc, choroid, and retinal vessels. The results indicated that increase in pallor and fluorescein-filling defect areas, as well as a slowed filling rate of the retinal veins, correlated with glaucomatous progression.

Aged↗
PubMed1992

Computer-based image analysis of prostate cancer: comments with emphasis on use of commercially available systems.

This review is concerned with computer-based image analysis (CBIA) in prostate cancer. The emphasis is placed on evaluating extent and grade of prostate cancer. The quest for reproducibility in these evaluations has provided an important area of possible application for CBIA studies. Commercially available CBIA systems allow an opportunity for increased efforts in studying the merits of CBIA in prostate cancer. Many CBIA systems with various capabilities are currently on the market. They can be described as either "general" or "dedicated" CBIA systems and are exemplified by two systems: the Werner Frei Imlab/Imtool (Werner Frei Associates, Venice, CA) and the CAS 200 (Cell Analysis Systems, Inc, Lombard, IL), respectively. "General" systems are composed of individual components with data being stored and analyzed using a personal computer (Werner Frei Imlab/Imtool). "Dedicated" systems are integrated systems, usually with little variability of either software or hardware specifications (CAS 200). It is helpful to be cognizant of the contrasting abilities provided by these two systems when evaluating which CBIA system would be most appropriate for a particular application in the study of prostate cancer.

Humans↗
PubMed1994

Quantitative computer image analysis of a human chorionic gonadotropin colloidal carbon dipstick assay.

Colloidal particles are widely used in qualitative dipstick assays for the determination of various proteins and haptens. Recently, a new colloidal label has been introduced based on elemental carbon. With this carbon label we have prepared a human chorionic gonadotropin-specific dipstick assay with a sensitivity of 10 mIU/ml. In addition, an image- and data-processing procedure for the quantification of the dipstick assay has been developed. The sum of the pixel grey levels of a carbon line was taken as a measure for this quantitative purpose. The measurement range of the assay is almost three orders of magnitude, i.e. 10 mIU/ml to 500 mIU/ml. The deviation from the mean of two dipstick determinations was 1.22% on average. The within-run and between-run precision, expressed as coefficients of variation at 50 mIU/ml were 1.03% and 1.84%, at 150 mIU/ml 2.14% and 3.77% and at 450 mIU/ml 2.55% and 5.28%, respectively. We have correlated this quantitative sol particle immunoassay with a commercial human chorionic gonadotropin specific radioimmunoassay. In an experiment with 25 human urine samples containing the hormone in amounts from 5 to 300 mIU/ml the correlation coefficient was 0.999. The sol particle immunoassay quantified by computer image analysis has been termed Sol particle Image Processed ImmunoAssay (SIPIA).

Carbon↗