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PubMedDate not supplied

Porosity determination of ceramic materials by digital image analysis--a critical evaluation.

Measuring the porosity of materials by digital image analysis of micrographs is a well-established and convenient method for the testing of metallic samples. However, when applied to ceramic materials, this method has been shown to be much less reliable and poorly reproducible. The purpose of this present work is to clarify the reason for this deficiency, involving many porosity measurements, performed on plasma-sprayed zirconia, under systematically varied microscopic imaging conditions, and the porosities being calculated using various evaluation methods. Comparison between of the results has shown that the present state of the image analysis method is not satisfactory for absolute porosity measurements on ceramic materials. It can be useful as a convenient tool for comparative measurements, however, if the imaging conditions maintained in the microscope and the evaluation method are held to be exactly identical.

Journal Article↗
PubMedDate not supplied

Use of image analysis in determining masticatory efficiency in patients presenting for immediate dentures.

Image analysis was used to determine masticatory efficiency and performance before and after placement of immediate dentures. Sections of cored carrot were used as the test food and the particle size of chewed expectorated food was measured using image analysis. Measurements were shown to be accurate and reproducible. Masticatory function of immediate-denture patients was also compared with a similar number of dentate individuals and experienced complete-denture wearers. Dentate subjects were significantly (P less than .01) more efficient at masticating the test food than were the complete- or immediate-denture wearers. The new method of measurement removes the necessity for the unpleasant and unhygienic sieving process previously used in this type of study.

Denture, Complete, Immediate↗
PubMed1997

Application of computerised image analysis to monitoring endodontic therapy: reproducibility and comparison with visual assessment.

OBJECTIVE: To evaluate the intra- and interexaminer reproducibility of computerised image analysis for the assessment of periapical bone changes based on gray value ratio when compared with a visual method. METHODS: 353 radiographs obtained in a clinical endodontic study were analysed. Densitometric analyses were used to evaluate changes in bone density following endodontic treatment. The diseased area of apical periodontitis' (AP) and 'normal bone area' (AN) were defined and ratios of the gray values (AP/AN) were calculated for each radiograph. Periapical index (PAI) was used as the 'gold standard'. Correlation coefficient (r), Kappa (kappa), and t-test for matched pairs were used for the statistics. RESULTS: The method proyed to be reproducible for intra-examiner re-examinations, r ranging from 0.7 to 0.84 (P < 0.01). Kappa showed fair to good agreement for data divided into four or three categories (kappa = 0.25-0.64). Dichotomised data showed fair to moderate agreement (kappa = 0.33-0.4) when the whole process was repeated, and good to very good agreement (kappa = 0.64-0.85) for the delineation process alone. The interexaminer comparisons showed fair to moderate agreement (kappa = 0.3-0.49). Comparison with PAI showed a 61% sensitivity and 79% specificity in detecting severe lesions (corresponding PAI scores 4 and 5) and the kappa value of 0.40 showed moderate agreement. The image analysis was sensitive enough to detect healing one month after treatment in a group of teeth with substantial lesions (P < 0.05). CONCLUSIONS: The computerised image analysis system seems to be an appropriate tool to detect the periapical bone changes in dental radiographs at a group level.

Bone Density↗
PubMed1988

Quantitative evaluation of coat-color patterns in artificially produced chimeras of the mouse by means of a microcomputer-based video-image analysis system.

The possible application of microcomputer-based video-image analysis systems for the quantitative description of coat-color patterns in artificially produced chimeras and genetic mosaics of mice was investigated using a program developed by the author. This system is capable of extracting, from sampled images of pelts, the morphometric image features as defined by Pratt [1978] that are essential to the quantitative description of coat-color patterns in these animals. It does so with reasonable accuracy and speed and at low cost. No description of any similar system has been published in the literature. Performance of our system is described using C3H/HeJ----BALB/c chimeras as examples. The complex phenotypic expression of hair pigmentation in mice makes the use of a video-image analysis system like this one essential to evaluate the morphometric parameters of the patterns (e.g., the mixing ratios between the two components, the number of different-colored stripes, etc.) more precisely and reproducibly than has been done yet in the literature. The results indicate that the number of melanoblast clones in mice, as estimated from the number of minimal recognizable stripes (MRS), might be considerably larger than previously indicated; the figure presently obtained, i.e., 22.3 +/- 2.16 unilaterally in terms of the hypothetical maximum number of stripes (HMNS) (28.73 +/- 1.55, after correction for the random clumping) in the thoracicolumbar region of the mouse closely approximates the number of the somites in that region. Concerning the degree of mixing between the two components, it was proposed that the unmixed portion of the components derived from one strain increases in proportion to the second power of the increase in the relative total content of the same components. Work is in progress in our laboratory to analyze a large number of the chimeric pelts using the system described in this paper.

Animals↗
PubMed1995

Quantitative image analysis of MIB-1 immunoreactivity. A comparison with flow cytometric assessment of proliferative activity in invasive carcinoma of the breast.

Proliferative activity, especially flow cytometrically determined S-phase fraction, is generally accepted as an important prognostic indicator in carcinoma of the breast. We studied cellular proliferation in 53 breast carcinomas using quantitative image analysis of immunoreactivity to a recently available monoclonal antibody, MIB-1, which is applicable to formalin-fixed, paraffin-embedded tissues. MIB-1 is a murine monoclonal antibody that reacts with the Ki-67 nuclear antigen expressed by proliferating cells in the late G1, and G2/M phases of the cell cycle. These results were compared to flow cytometric determinations of S-phase and S + G2/M phase fractions obtained from corresponding fresh tissue samples. There was a good correlation between quantitative immunoreactivity to MIB-1 as measured by image analysis and flow cytometric S-phase and S + G2/M phase fractions (r = .63, P < .00001; r = .607, P < .00001, respectively). Immunoreactivity to MIB-1 and flow cytometric S-phase and S + G2/M phase fractions were significantly increased in aneuploid tumors as compared to diploid tumors. Histologic grade correlated with flow cytometric S-phase and S + G2/M phase fractions and MIB-1 immunoreactivity as determined by image analysis. There was a correlation between tumor size and MIB immunoreactivity. No proliferative parameters significantly correlated with lymph node status. Assessment of proliferative activity by quantitative image analysis of immunoreactivity to monoclonal MIB-1 antibody may be employed in cases of invasive carcinoma of the breast in which flow cytometric analysis fails to result in quantitative proliferative values, or it may be used as an alternative measurement of such proliferative activity.

Adenocarcinoma↗
PubMed2005

Image analysis for cDNA microarrays.

OBJECTIVES: We characterize typical problems encountered in microarray image analysis and present algorithmic approaches dealing with background estimation, spot identification and intensity extraction. Validation of the quality of resulting measurements is discussed. METHODS: We describe sources for errors in microarray images and present algorithms that have been specifically developed to deal with such experimental imperfections. RESULTS: For the image analysis of hybridization experiments, discriminating spot regions from a background is the most critical step. Spot shape detection algorithms, intensity histogram methods and hybrid approaches have been proposed. The correctness of final intensity estimates is difficult to verify. Nevertheless, the application of sophisticated algorithms provides a significant reduction of the possible information loss. CONCLUSIONS: The initial analysis step for array hybridization experiments is the estimation of expression intensities. The quality of this process is crucial for the validity of interpretations from subsequent analysis steps.

Algorithms↗
PubMed2000

Development of an on-line monitoring system of human keratinocyte growth by image analysis and its application to bioreactor culture.

Human keratinocytes were cultured in serum-free medium for the purpose of on-line cell growth monitoring by image analysis. The validity of a process using a newly developed video microscopy system with image analysis for growth-rate monitoring in real time was verified by the measurement of the degree of confluence of keratinocytes in T-flasks and Petriperm dishes. The growth rate of keratinocytes was calculated subsequently from the linear relationship between average degree of confluence and cell concentration. This technique was applied to the culture in the bioreactor "KERATOR" in which a special video microscopy system using a CCD camera was built. The cell concentration evaluated by image analysis agreed well with that evaluated by conventional direct cell counting after enzymatic digestion, and the on-line monitoring of the specific growth rate allowed identification of both lag- and exponential-growth phases of the culture.

Bioreactors↗
PubMed1990

DNA ploidy in breast lesions. A comparative study using two commercial image analysis systems and flow cytometry.

DNA ploidy determinations on a series of 24 breast specimens were performed independently utilizing flow cytometry (FCM) and two separate commercially available computerized image analysis systems for image cytometry (ICM). The tissues analyzed were obtained from 20 carcinomas, 2 benign neoplasms and 2 benign reductive procedures. The results showed a close correlation between the DNA indices (DIs) obtained by all methods in 14 of the 24 cases. In four cases, all methods showed aneuploid peaks, but with differing DIs. In six cases (two benign and four malignant) FCM showed diploidy while ICM showed peridiploid cell populations. The results obtained with the two image analysis systems were in agreement for 20 of the 24 cases. ICM is an acceptable alternative to FCM for reproducible ploidy analysis. ICM-based measurements have the advantage of the visual discrimination of abnormal cells and therefore may have a greater sensitivity in identifying small aneuploid populations. Populations with DIs in the range of 1.0 to 1.3 need to be assessed carefully in ICM-based determinations due to the potential that these "aneuploid" peaks may represent shifted diploid populations.

Breast Diseases↗
PubMedDate not supplied

Image analysis of neurofilament immunoreactivity in human spiral ganglion.

Computer-assisted image analysis was used to study the immunoreactivity to NF-L, NF-M and NF-H in human spiral ganglion cells. The concentrations, represented by the relative mean grey of NF-L, NF-M and NF-H, were calculated and compared. The cell-area mean-grey correlations for NF-L, NF-M and NF-H were analysed and calculated, showing that NF-M is more specific to the larger cells (type 1?) and NF-H is more specific for the smaller cells (type 2?), while NF-L is non-specific for cell size. These findings confirm several previous assumptions by providing a quantitative basis. We conclude that image analysis is a useful-even essential-tool for the analysis of immunostained temporal bone sections.

Adolescent↗
PubMed2003

Improved identification of potentially dangerous pigmented skin lesions by computerized image analysis.

BACKGROUND: Melanoma is completely curable if resected early. Unfortunately, early melanoma can be difficult to differentiate from other pigmented lesions. Computerized image analysis instruments have now been developed to assist in determining whether a pigmented lesion is potentially dangerous and requires biopsy. To evaluate whether one such instrument can improve the management of pigmented lesions, we obtained biopsy specimens from 52 pigmented lesions that appeared clinically benign to an experienced dermatologist but were suspicious by image analysis. OBSERVATION: Histologically, 9 (17%) of the lesions that were removed based solely on computer recommendation were potentially dangerous and should have been removed. These included 1 malignant melanoma in situ and 8 dysplastic nevi with moderate to severe cytologic atypia. CONCLUSION: The results of the present study indicate that computerized image analysis can improve the evaluation of pigmented skin lesions by identifying clinically unsuspicious, but potentially dangerous, lesions that might have otherwise have been neglected.

Biopsy, Needle↗
PubMedDate not supplied

[An analysis of the tumor growth rate in neuroma of the VIII cranial nerve using a digital image analysis system].

A digital image analysis system was used in a retrospective analysis of MRI findings in 9 patients with acoustic neuroma. Maximum and minimum tumor diameters and surface area were measured and tumor volume was calculated. All studies included intravenous injection of gadolinium (Gd-DTPA or DOTA) and axial and coronal sections. Tumoral growth rate was analyzed using the increase in tumor size ( T) tumor area doubling time (ADT), and tumor volume doubling time (VDT). The purpose of this study was to document the growth rate of acoustic neuromas with periodic MRI. In an era in which preservation of hearing and the facial nerve is a goal of acoustic neuroma surgery, knowledge of tumor growth rate should improve patient care.

Aged↗
PubMed1996

Image analysis of cellular DNA content in peritoneal fluid of patients with ovarian tumors of low malignant potential and invasive epithelial ovarian cancer.

Image analysis has rarely been used to quantitate the DNA content of intact cells derived from peritoneal fluid in patients with ovarian malignancy. An average of 118 (range 100-208) of the most atypical, visually selected Feulgen-stained cells in peritoneal fluid obtained from 46 patients undergoing primary cytoreductive surgery for histologically proven ovarian tumors of low malignant potential and truly invasive ovarian cancer were evaluated retrospectively using the SAMBA-4000 Image analysis system. The patients were stratified into 3 groups: 16 with ovarian tumors of low malignant potential (LMP), 14 with low-stage disease (LSD) (FIGO I and II), and 16 with advanced-stage (ASD) (FIGO III and IV). A pattern of high-degree aneuploidy with negative balance (means: LMP, 3.3; LSD, 20.5; ASD, 32.0), increased proliferative index (LMP, 11.2; LSD, 16.1; ASD, 13.9), and percentage of cells with DNA content greater than 5C (LMP, 6.7; LSD, 6.5; ASD, 9.5) was demonstrated in the peritoneal fluid of 8 of 16 patients with LMP (50%), 8 of 14 patients with LSD (57%), and 13 of 16 with ASD (81%). The median disease-free interval for patients with invasive epithelial ovarian cancer with peritoneal DNA diploid tumor cells was 57 months and for those with DNA aneuploid tumor cells 28 months, while in patients with LMP it was 65 and 54 months, respectively. In total, 19 patients developed a recurrence (LMP, 2; LSD, 5; ASD, 12) of which 17 were shown to have DNA aneuploid cells in the peritoneal fluid. Multivariate analysis, however, did not identify aneuploid population in the fluid, ploidy balance, proliferation indices, or degree of hyperploidy as an independently significant variable for predicting recurrence. It did appear, however, that tumor cells in peritoneal fluid with a degree of hyperploidy greater than 8 had a strong correlation for development of recurrence, although not statistically significant. Interactive image analysis of tumor cells in peritoneal fluid proved to be a valuable adjunct to cytodiagnosis. Seven of 28 patients (25%) who were underdiagnosed by cytology alone (LMP, 2; LSD, 3; ASD, 2) were shown to have malignant cells in their peritoneal fluid, while 2 of 18 patients (11%) who were called positive by cytology (LMP, 1; LSD, 1) showed diploid pattern histograms and upon review were interpreted as reactive mesothelial cells.

Adult↗
PubMedDate not supplied

A new digital image analysis system useful for surface assessment of vitiligo lesions in transplantation studies.

So far there is no uniformity in the evaluation methods used in the assessment of treatment outcome in vitiligo studies. The ability to objectively measure surfaces of vitiligo lesions is important for both clinical practice and research. Our objective was to assess the reproducibility, accuracy, user-friendliness and time effectiveness of a new digital image analysis system for surface measurement of vitiligo lesions. Three different observers performed both a visual estimation and a digital image analysis on 30 images of 10 vitiligo lesions. Inter- and intra-observer variation were evaluated and results were compared with the 2D gold standard measurements and a 3D measurement. A high inter- and intra-observer variability was observed for the visual estimation of surfaces. With the digital image analysis system a significant improvement of the reproducibility was achieved (p = 0.01). Moreover, results were accurate and the measurement procedure was user-friendly. Importantly, a systematic underestimation was demonstrated when comparing the 2D with the 3D measurements. We introduced an objective measurement method that might be useful in the future for consistently measuring surfaces of selected vitiligo lesions both before and after different therapeutic modalities.

Adolescent↗
PubMed1993

[Image analysis on isolated colorectal tumor cells].

Image analysis of the nuclear morphology was performed on propidium iodide-stained isolated cells from 9 adenomas and 9 cancers of the colorectum. We analyzed DNA content, seven nuclear geometric features and four shape factors of tumor cells using an image cytometry system that has been developed in our laboratory. Nuclear breadth and the degree of contour irregularity of cancer cells were found to be significantly different from those of adenoma cells. The coefficients of variation (CV) of some nuclear features and the degree of contour irregularity were increased in cancer cells, while CV of the degree of circularity was increased in adenoma cells. Moreover, nuclear in G2 phase were found to be larger and more round than those in G1 phase. These results suggest that cell-cycle-related analysis of nuclear features would be a valid means to assess the nuclear morphology of colorectal tumors.

Adenocarcinoma↗
PubMed2002

Tumor hypoxia and blood vessel detection: an image analysis technique for simultaneous tumor hypoxia grading and blood vessel detection in tissue sections.

We have developed a multistage image analysis technique for the simultaneous segmentation of blood vessels and hypoxic regions in dual-stained tumor tissue sections. The algorithm, which is integrated in a task-oriented image analysis system developed on-site, initially uses the K-nearest neighbor classification rule in order to label the image pixels. Classification is based on a training set selected from manually drawn regions corresponding to the areas of interest. If the output image contains a significant number of misclassified pixels, the user has the option to apply a series of specific problem-designed routines (texture analysis, fuzzy c-means clustering, and edge detection) in order to improve the final segmentation result. Validation experiments indicate that the algorithm can robustly detect these biological features, even in tissue sections with a very low quality of staining. This approach has also been combined with other image analysis based procedures in order to objectively obtain quantitative measurements of potential clinical interest.

Algorithms↗
PubMed1995

A color image analysis method for assessment of germination based on differential fluorescence staining of bacterial spores and vegetative cells using acridine orange.

Color fluorescence image analysis of acridine orange (AO) stained germinating Bacillus subtilis var. niger bacteria revealed a cell population initially dominated by small green spores followed by the emergence of at least three additional discernible subpopulations in response to stimulation with D-glucose. These subpopulations were small, round or oblong red cells; intermediate to large metachromatic cells; and large red rods. Large green rods were rarely observed. An increase in red emissions (i.e., putative RNA synthesis) was sometimes seen as early as 90 min after exposure to D-glucose and uptake of AO at room temperature. This may represent either metabolic recovery from quiescence or RNA synthesis associated with germination. In the absence of D-glucose, or using autoclaved bacteria in the presence of glucose, no relative increase in the red signal was observed despite hours of observation. Digital image analysis was used for relative measurement of red, green and blue signals and to correlate the size of various subpopulations with their fluorescence color emissions over time. Image analysis demonstrated a trend toward increasing size and red emission in the presence of glucose. The average red emission was found to be a good discriminator of the various subpopulations, while the average green emission was approximately equal among the subpopulations making it a poor discriminator. These data suggest that AO staining might be used for rapid computer-assisted discrimination of spores vs. vegetative cells.

Acridine Orange↗
PubMed1994

Image analysis as a tool for quantitative enzyme determination at the cellular level: application for monocytic differentiation of the UM-384 cell line.

Image analysis has been used to determined enzyme activity at the cellular level in individual smeared cells. The counterstains used to visualize smeared cells were chosen to avoid overlap with the chromogene. The amount of the reaction product was quantified by computerised scanning cytophotometry when the conditions of incubation, time and temperature of the reaction, and substrate concentration varied. Under optimal conditions for time, temperature and substrate concentration, a linear relationship was found between enzyme activity determined on smeared cells and in cell lysate. Using these defined conditions, differentiation of UM-384 cells was studied by measuring enzyme activity. After a monocytic differentiation process, induced by sodium butyrate, non-specific esterase cell activity was compared either with differentiation markers (HLA-DR, plasminogen activator inhibitor type 2 and lysozyme) or with markers of proliferation (DNA content) or functional properties (nitroblue tetrazolium reduction and phagocytosis). The results show that, using image analysis, non-specific esterase seems to be a useful means for the assessment of monocytic differentiation whereas myeloperoxidase is not. More generally, quantification of enzyme activity at the cellular level using image analysis can be applied to the study of the differentiation process and may help in the classification of leukemic cells.

Acid Phosphatase↗
PubMed1995

Gingival overgrowth induced by nifedipine and cyclosporin A. Clinical and morphometric study with image analysis.

In this study, we developed a quantitative method with digital image analysis to evaluate the degree of gingival overgrowth (GO), and compared GO in kidney transplant patients treated with cyclosporin A (CsA) (n = 21) or CsA+nifedipine (n = 8) and a group of healthy controls (n = 30). The method was reproducible and reliable. Our findings showed significant differences in papillary and gingival surface between controls and transplant patients treated with GO inducers. Gingival overgrowth index also differed significantly between controls and each patient group (p < 0.01, Kruskal-Wallis test). The administration of the calcium channel blocker nifedipine potentiated the adverse effect of CsA: comparison of the morphometric findings revealed significant differences between patients treated with CsA alone and CsA+nifedipine in papillary area, dental area, and GO index (p < 0.01, Mann-Whitney U-test). We conclude that the method of image analysis we developed is useful in assessing the degree of GO.

Adult↗