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PubMed1997

Application of automatic thresholding in image analysis scoring of cells in human solid tumors labeled for proliferation markers.

We previously reported an image analysis program that uses four investigator-defined parameters including two thresholds, i.e., gray-level threshold (GLT) and hue threshold (HT), to determine the number of cells (TC) and the proliferating cell nuclear antigen (PCNA) or bromodeoxyuridine (BrdUrd) labeling indices (LI) in human solid tumors. The present study investigated if the accuracy and reproducibility of image analysis results can be improved by using computer-defined GLT and HT. Three investigators evaluated 142 images on 3 days, using visual analysis and four image analysis routines, which used different combinations of computer- and investigator-selected GLT and HT. The data show that image analysis using computer-selected GLT and HT yielded (i) LI of PCNA and BrdUrd that were indistinguishable from visual analysis, (ii) equal (BrdUrd LI) or better (TC and PCNA LI) inter-day reproducibility relative to visual analysis results, and (iii) results that were equally (TC) or more accurate (LI of PCNA and BrdUrd) with higher inter-day reproducibility (TC and LI of PCNA and BrdUrd) than image analysis obtained using investigator-defined thresholds. We conclude that the use of computer-defined GLT and HT improved the accuracy and reproducibility of image analysis results.

Analysis of Variance↗

PubMed1982

An accurate means of detecting and characterizing abnormal patterns of ventricular activation by phase image analysis.

The ability of scintigraphic phase image analysis to characterize patterns of abnormal ventricular activation was investigated. The pattern of phase distribution and sequential phase changes over both right and left ventricular regions of interest were evaluated in 16 patients with normal electrical activation and wall motion and compared with those in 8 patients with an artificial pacemaker and 4 patients with sinus rhythm with the Wolff-Parkinson-White syndrome and delta waves. Normally, the site of earliest phase angle was seen at the base of the interventricular septum, with sequential change affecting the body of the septum and the cardiac apex and then spreading laterally to involve the body of both ventricles. The site of earliest phase angle was located at the apex of the right ventricle in seven patients with a right ventricular endocardial pacemaker and on the lateral left ventricular wall in one patient with a left ventricular epicardial pacemaker. In each case the site corresponded exactly to the position of the pacing electrode as seen on posteroanterior and left lateral chest X-ray films, and sequential phase changes spread from the initial focus to affect both ventricles. In each of the patients with the Wolff-Parkinson-White syndrome, the site of earliest ventricular phase angle was located, and it corresponded exactly to the site of the bypass tract as determined by endocardial mapping. In this way, four bypass pathways, two posterior left paraseptal, one left lateral and one right lateral, were correctly localized scintigraphically. On the basis of the sequence of mechanical contraction, phase image analysis provides an accurate noninvasive method of detecting abnormal foci of ventricular activation.

Adult↗

PubMed2004

Hybrid clustering for microarray image analysis combining intensity and shape features.

BACKGROUND: Image analysis is the first crucial step to obtain reliable results from microarray experiments. First, areas in the image belonging to single spots have to be identified. Then, those target areas have to be partitioned into foreground and background. Finally, two scalar values for the intensities have to be extracted. These goals have been tackled either by spot shape methods or intensity histogram methods, but it would be desirable to have hybrid algorithms which combine the advantages of both approaches. RESULTS: A new robust and adaptive histogram type method is pixel clustering, which has been successfully applied for detecting and quantifying microarray spots. This paper demonstrates how the spot shape can be effectively integrated in this approach. Based on the clustering results, a bivalence mask is constructed. It estimates the expected spot shape and is used to filter the data, improving the results of the cluster algorithm. The quality measure 'stability' is defined and evaluated on a real data set. The improved clustering method is compared with the established Spot software on a data set with replicates. CONCLUSION: The new method presents a successful hybrid microarray image analysis solution. It incorporates both shape and histogram features and is specifically adapted to deal with typical microarray image characteristics. As a consequence of the filtering step pixels are divided into three groups, namely foreground, background and deletions. This allows a separate treatment of artifacts and their elimination from the further analysis.

Algorithms↗

PubMed1989

Rapid enumeration of viable bacteria by image analysis.

A direct viable counting method for enumerating viable bacteria was modified and made compatible with image analysis. A comparison was made between viable cell counts determined by the spread plate method and direct viable counts obtained using epifluorescence microscopy either manually or by automatic image analysis. Cultures of Escherichia coli, Salmonella typhimurium, Vibrio cholerae, Yersinia enterocolitica and Pseudomonas aeruginosa were incubated at 35 degrees C in a dilute nutrient medium containing nalidixic acid. Filtered samples were stained for epifluorescence microscopy and analysed manually as well as by image analysis. Cells enlarged after incubation were considered viable. The viable cell counts determined using image analysis were higher than those obtained by either the direct manual count of viable cells or spread plate methods. The volume of sample filtered or the number of cells in the original sample did not influence the efficiency of the method. However, the optimal concentration of nalidixic acid (2.5-20 micrograms ml-1) and length of incubation (4-8 h) varied with the culture tested. The results of this study showed that under optimal conditions, the modification of the direct viable count method in combination with image analysis microscopy provided an efficient and quantitative technique for counting viable bacteria in a short time.

Colony Count, Microbial↗

PubMed2003

Image analysis method for evaluation of specific and non-specific hand contamination.

AIMS: To evaluate a quantifying image analysis method for assessing the degree of hand contamination and efficacy of hand washing procedures. METHODS AND RESULTS: Two types of experimental design were used. In one, different concentrations of pure cultures of Escherichia coli, Listeria innocua and Pseudomonas flourescens were applied to hands. In the other, hands were contaminated by handling various raw foods. Imprints of the contaminated palms were made on 24.5 x 24.5 cm agar plates using appropriate agars. After incubation, digital photographs of the plates were analysed using image analysis. In pure culture studies with selective agars, levels from 1 to 10(6) CFU cm(-2) palm could be monitored. For aerobic, mesophilic organisms from raw chicken, levels from 10(3) to 10(6) CFU cm(-2) palm were correlated linearly to image analysis data. CONCLUSIONS: The image analysis of palm imprints made on agar plates was suitable for assessing the degree of contamination from foods on the palms. Sensitivity and specificity depended on the agar used and the type of contamination encountered. SIGNIFICANCE AND IMPACT OF THE STUDY: Data capture by the image analysis method is simple and can be partly automated. Sampling time is short for the person to be tested, which makes it an attractive method for assessing hand hygiene status in larger field trials.

Agar↗

PubMed1998

Coupling of image analysis and tenderness classification to simultaneously evaluate carcass cutability, longissimus area, subprimal cut weights, and tenderness of beef.

The present experiment was conducted to determine whether image analysis of the 12th-rib cross-section used for tenderness classification could accurately predict carcass cutability, longissimus area, and subprimal cut weights. The right side of crossbred steer and heifer carcasses (n=66) was fabricated, and the yield of totally trimmed retail product was determined. Following procedures that we have described for tenderness classification, a 2.54-cm-thick steak was removed from the 12th-rib region of the left side of each carcass, and image analysis was conducted using off-the-shelf technology. Image analysis accounted for more of the variation in retail product yield (RPYD; 89 vs 77%) and retail product weight (95 vs 90%) than did calculated yield grade. Also, image analysis accurately predicted longissimus area (R2=.88). For most subprimals, the combination of image analysis-predicted RPYD and hot carcass weight (HCW) accounted for more of the variation in subprimal weight than did the combination of calculated yield grade and HCW. Whereas HCW, by itself, accounted for only 30 to 34% of the variation in weights of round cuts, the combination of image analysis-predicted RPYD and HCW accounted for 78 to 82% of the variation in weights of round cuts. Hot carcass weight, the combination of calculated yield grade and HCW, and the combination of image analysis-predicted RPYD and HCW accounted for 54, 83, and 91% of the variation in the weight of 80% lean trimmings. Thus, image analysis could be used by the beef industry to more accurately predict individual subprimal weights. In turn, that information and appropriate price extensions could be used to more accurately estimate carcass value. Thus, image analysis could be used by the beef industry in combination with tenderness classification to accurately characterize beef carcasses for cutability and tenderness. These tools should help facilitate the development of value-based marketing systems.

Adipose Tissue↗

PubMed2002

Validation of image analysis for enzyme histochemical and immunocytochemical staining.

Immunocytochemical and enzyme histochemical analyses of cells and tissues are used to detect changes in the extent of injury and the expression of various molecules. Image analysis quantitation offers an easier, more efficient technique to evaluate these changes. We studied the application of image analysis for evaluating enzyme histochemistry and immunocytochemistry of cells and tissues as a way to assess stroke. Using brain sections, we compared investigator and computer-generated image analysis of 2,3,5-triphenyltetrazolium chloride stained cerebral infarcts in rats subjected to 2 h middle cerebral artery occlusion and 22 h re-perfusion. Both methods documented the infarct volumes with a comparison of means of less then 5%. This suggests no difference between computer- and hand-calculated values. Computer-generated analysis was easier and faster to use. Using endothelial cell monolayers, immunocytochemical staining of a time course of heat shock protein expression was compared to a grading system using fast red chromagen counterstained with hematoxylin. Results demonstrated greater ease and efficiency with computer-generated image analysis compared to other subjective systems of analysis. Image analysis is more useful for detecting small differences in staining, especially when using 3,3-diaminobenzidine as a chromagen. Investigator bias is also reduced using this system. Our comparisons validate the use of this versatile technology to assess more easily both cell and tissues in stroke research.

Animals↗

PubMed1991

Comparison of image analysis and flow cytometric determination of cellular DNA content.

A good correlation (r = 0.94) was obtained between the DNA indices (DI) using flow cytometry and image analysis of nuclei cytospins extracted from paraffin wax embedded tumour sections. Some of the limitations and problems associated with image analysis which came to light included an unacceptably high coefficient of variation (CV) and a "left-shift" in the DI in most DNA histograms obtained when using image analysis of 5 microns sections. In contrast, the DNA histograms generated using image analysis of cytospun nuclei from paraffin wax blocks were of good quality and similar to those obtained using flow cytometry. Variability in Feulgen staining was common and an important source of error despite rigorous control of the staining technique. This could be overcome by using internal controls such as fibroblasts rather than external controls (rat hepatocytes) to determine the diploid DI with image analysis. A thorough understanding and appreciation of the methodological problems associated with image analysis and flow cytometric determination of DNA content is required before these methods find widespread clinical application.

Adrenal Gland Neoplasms↗

PubMed1992

The microcomputer and image analysis in diagnostic pathology.

This paper presents a snapshot view of the influence and direction of microcomputer technology for image analysis techniques in diagnostic pathology. Microcomputers have had considerable impact in bringing image analysis to wider application. Semi-automated tracing techniques are a simple means of providing objective data and assist in a wide range of diagnostic problems. From the common theme of reducing subjectivity in diagnostic assessment, an extensive body of research has accrued. Some studies have addressed the need for quality control for reliable, routine application. Video digitizer cards bring digital image analysis within the reach of laboratory budgets, providing powerful tools for investigation of a wide range of cellular and tissue features. The use of staining procedures compatible with quantitative evaluation has become equally important. As well as assisting scene segmentation, cytochemical and immunochemical staining techniques relate the data to biological processes. With the present state of the art, practical use of microcomputer based image analysis is impaired by limitations of information extraction and specimen throughput. Recent advances in colour video imaging provide an extra dimension in the analysis of multi-spectral stains. Improvements will also be felt with predictable increase in speed of microprocessors, and with single chip devices which deliver video rate processing. If the full potential of this hardware is realized, high-speed, routine analysis becomes feasible. In addition, a microcomputer imaging system can play host to companion functions, such as image archiving and transmission. With this outlook, the use of microcomputers for image analysis in diagnostic pathology is certain to increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2005

Improving lip wrinkles: lipstick-related image analysis.

BACKGROUND/PURPOSE: The appearance of lip wrinkles is problematic if it is adversely influenced by lipstick make-up causing incomplete color tone, spread phenomenon and pigment remnants. It is mandatory to develop an objective assessment method for lip wrinkle status by which the potential of wrinkle-improving products to lips can be screened. The present study is aimed at finding out the useful parameters from the image analysis of lip wrinkles that is affected by lipstick application. METHODS: The digital photograph image of lips before and after lipstick application was assessed from 20 female volunteers. Color tone was measured by Hue, Saturation and Intensity parameters, and time-related pigment spread was calculated by the area over vermilion border by image-analysis software (Image-Pro). The efficacy of wrinkle-improving lipstick containing asiaticoside was evaluated from 50 women by using subjective and objective methods including image analysis in a double-blind placebo-controlled fashion. RESULTS: The color tone and spread phenomenon after lipstick make-up were remarkably affected by lip wrinkles. The level of standard deviation by saturation value of image-analysis software was revealed as a good parameter for lip wrinkles. By using the lipstick containing asiaticoside for 8 weeks, the change of visual grading scores and replica analysis indicated the wrinkle-improving effect. As the depth and number of wrinkles were reduced, the lipstick make-up appearance by image analysis also improved significantly. CONCLUSION: The lip wrinkle pattern together with lipstick make-up can be evaluated by the image-analysis system in addition to traditional assessment methods. Thus, this evaluation system is expected to test the efficacy of wrinkle-reducing lipstick that was not described in previous dermatologic clinical studies.

Adult↗

PubMed1998

Objective nuclear grading for node-negative breast cancer patients: comparison of quasi-3D and 2D image-analysis based on light microscopic images.

In a retrospective investigation for a new image-analytical nuclear grading method, we used 145 routine hematoxylin and eosin-stained, paraffin-embedded tissue sections from node-negative breast carcinomas. Cell fields of primary tumors were scanned in a light microscope in successive focus levels in 1-micron steps for thick sections (> or = 5 microns: quasi-3D analysis) and in one focus position for thin sections (< 5 microns: 2D analysis). After image-segmentation, nuclear features for texture and chromatin distribution were calculated. A binary classification tree was constructed for determination of two mathematically defined classes of high- and low-risk tumor cell nuclei. After fixing a cut-point for the portion of high-risk tumor cell nuclei per patient, it was possible to distinguish two different groups with significantly different relapse rates of 4.2% and 74.5% in quasi-3D analysis and 0.0% and 52.0% in 2D analysis, respectively. Large differences between quasi-3D and 2D analysis were only present in the classification of nonrelapse patients, whereas nearly all patients with relapse had more than 50% high-risk tumor cell nuclei. The results show that the information in thicker tissue sections contains important additive components in the third dimension, with respect to the detection of chromatin structure and distribution. This advantage should be exploited for the development of an objective image-analytical nuclear grading system as a highly significant prognostic marker.

Adult↗

PubMed2001

Modified silver staining of nucleolar organizer regions to improve the accuracy of image analysis.

Silver staining of nucleolar organizer regions (NORs) and their subsequent quantification by image analysis are used increasingly in human pathological specimens and experimental models. Because certain conditions determined by the type of tissue and/or its fixation render AgNOR segmentation for image analysis difficult due to insufficient contrast or nonspecific silver precipitation, we propose three improvements to the original technique to overcome these difficulties. Pretreatment with 7% nitric acid produced very distinct dark brown images of AgNORs on a yellow background. The gradient of background colors allowed easy discrimination of nucleolar, nuclear and cytoplasmic structures. Seven morphometric parameters related to number, size and shape of AgNORs were evaluated quantitatively by image analysis on sections pretreated with nitric acid and on adjacent sections treated with citrate buffer in a wet autoclave according to the most widely accepted method for image analysis of AgNOR. Both methods yielded similar results. A second improvement was achieved by coating the slides with 7% celloidin solution in ethyl alcohol-ether prior to AgNOR staining and acid pretreatment. This coating prevented nonspecific silver deposition on argyrophilic bacteria and other tissue debris in human vaginal smears that could make visualizing AgNOR sites difficult. Finally, placing sections face down on the staining solution prevents the formation of nonspecific silver precipitates. These procedures can be applied together or separately according to the requirements of the material to be evaluated.

Adenocarcinoma↗

PubMed2002

Deformable organisms for automatic medical image analysis.

We introduce a new approach to medical image analysis that combines deformable model methodologies with concepts from the field of artificial life. In particular, we propose "deformable organisms", autonomous agents whose task is the automatic segmentation, labeling, and quantitative analysis of anatomical structures in medical images. Analogous to natural organisms capable of voluntary movement, our artificial organisms possess deformable bodies with distributed sensors, as well as (rudimentary) brains with motor, perception, behavior, and cognition centers. Deformable organisms are perceptually aware of the image analysis process. Their behaviors, which manifest themselves in voluntary movement and alteration of body shape, are based upon sensed image features, pre-stored anatomical knowledge, and a deliberate cognitive plan. We demonstrate several prototype deformable organisms based on a multiscale axisymmetric body morphology, including a "corpus callosum worm" that can overcome noise, incomplete edges, considerable anatomical variation, and interference from collateral structures to segment and label the corpus callosum in 2D mid-sagittal MR brain images.

Algorithms↗

PubMed1994

Comparative DNA analysis of breast cancer by flow cytometry and image analysis.

Measurement of DNA ploidy can be performed either with Flow Cytometry (FCM) and Image-Analysis (IA); both methods provide prognostic information in primary breast cancer. We compared the results of quantitative DNA analysis of formalin fixed, paraffin embedded tissue from 62 invasive ductal breast cancers. For FCM nuclear suspensions from disaggregated tumor were stained with Propidium Iodide and analyzed by means of Ortho Cytoron Absolute. For IA nuclear suspensions were stained by the Feulgen method and analyzed by means of Vidas system. We found a good correlation between flow cytometry DNA Index and Histogram Type, according to Auer classification (rs = 0.65, p < 0.001) and between DNA Index and Grading of Malignancy (MG) which had been measured by Bocking's algorithm (rs = 0.38, p < 0.05). Concerning to disease free survival (DFS), flow cytometric DNA Index showed a better correlation (rs = 0.56, p < 0.001). We concluded that the two methods provide comparable results, but offer individual advantages and are complementary for analyzing DNA ploidy in breast cancer.

Algorithms↗

PubMedDate not supplied

Modified true-color computer-assisted image analysis versus subjective scoring of estrogen receptor expression in breast cancer: a comparison.

BACKGROUND: Hormone receptor expression can be quantified by computerized image analysis in immunohistochemically stained specimens. When comparing semiquantitative scoring with computerized image analysis a review of the literature shows contradictory findings concerning the correlation of these two methods. Recent technical approaches have been developed with true-color computer-assisted image analysis facilitating new measurement designs. We performed a study with a new approach using the principle of semiquantitative assessment of hormone receptor content and measuring two different binary images (immunohistochemically stained nuclear area and total nuclear area). MATERIAL AND METHODS: Eighty formalin-fixed, paraffin-embedded and immunohistochemically stained breast cancer specimens were assessed for estrogen receptor expression by true color computer-assisted image analysis and by conventional light microscopy scoring according to Remmele (immunoreactive score (IRS) = staining intensity (SI) x percentage of positive cells (PP)). The results of both methods were correlated. RESULTS: Mean optical density (MOD) and subjective scoring of SI as well as stained nuclear area vs. total nuclear area and subjective scoring of stained cells (PP) showed a high correlation (Spearman correlation coefficient: 0.95, p-value: 0.0001 and 0.64, p-value: 0.0001, respectively). CONCLUSION: On the basis of this new technical approach our results confirm the correlation of semiquantitative hormone receptor scoring and quantitative computer-assisted image analysis. We believe that by automating electronic analysis in the near future we will be able to establish reliable observer-independent evaluation of immunohistochemical variables ensuing comparability in multi-center trials and cost efficiency.

Breast Neoplasms↗

PubMed1998

An improved procedure to quantify tumour vascularity using true colour image analysis. Comparison with the manual hot-spot procedure in a human melanoma xenograft model.

In a number of recent papers, the degree of tumour vascularization has been described as a promising new prognostic factor. Methods for the assessment of vascular density involve immunohistochemical staining of the vasculature, followed by counting the number of vessel profiles in the angiogenic hot spot. One of the problems of this procedure is the selection of the angiogenic hot spot, which has been described as being subject to inter-observer variation. In this study, the value of true colour image analysis in reducing inter-observer variation has been assessed. Highly (MV3) and poorly (M14) vascularized human melanoma xenografts were used to evaluate the image analysis procedure, and the image analysis results were compared with results from the conventional manual hot-spot procedure. Assessment by image analysis was performed on measurement fields covering the entire tumour tissue specimens rather than on a single hot-spot field. Also, by selecting the most densely vascularized area from all fields assessed by the semi-automatic procedure, it was possible to objectify the hot spot selection (automated hot-spot procedure). Manual assessment showed a good correlation between two independent observers for MV3 xenografts (r = 0.74, P = 0.014), but a poor correlation for M14 xenographs (r = 0.4, P > 0.05). Automated assessment by different operators showed good correlations for both MV3 xenografts (r = 0.99, P < 0.001) and M14 xenografts (r = 0.80, P = 0.006). It is concluded that although both manual vessel counting and semi-automated image analysis can differentiate between the level of vascularization in the two types of xenograft (P < 0.001 for both methods), the automated method is favourable in that it showed no significant inter-observer effects. In M14 xenografts, the manual hot-spot vessel densities did not correlate well with the automated hot-spot densities (r = 0.27, P > 0.05), indicating that selection of angiogenic hot spots in this tumour type is indeed subject to observer bias. The automated hot-spot vessel densities were a reliable indicator of overall tumour vessel density in both tumour types. Image analysis allows analysis of vessel subclasses based on morphological criteria such as vessel profile area or diameter. In the model system used, the discrimination between MV3 and M14 xenografts was further enhanced by selectively examining vessels with diameters between 6 and 9 microns (P < 0.0005). In conclusion, image analysis appears to offer an objective and more reproducible method to quantify tumour vascularity than manual counting of vessel profiles in the hot spot. Analysis of subclasses of vessels may further enhance the value of vessel density measurements in discriminating between tumour types differing in biological behaviour.

Animals↗

PubMed1996

DNA image analysis of urinary cytology: prediction of recurrent transitional cell carcinoma.

To evaluate the utility of image analysis in monitoring patients with transitional cell carcinoma, we studied, by cytologic means and by image analysis, 78 urinary tract specimens from 66 patients, of whom 49 (74%) had a previous history of transitional cell carcinoma. The specimens consisted of 51 (65%) voided urine specimens, 12 (15%) bladder washings, 8 (10%) ureteral washings, 3 (4%) ureteral brushings, 2 (3%) renal pelvic washings, and 2 (3%) catheterized urine specimens. DNA histograms were classified into five patterns on the basis of their DNA index and the percentage of their cells with DNA content greater than 5c: diploid (single peak in the 2c region with no cells greater than 5c), intermediate (diploid with less than 10% of cells greater than 5c), aneuploid (single peak or multiple peaks between the 2c and 4c region or more than 10% of cells greater than 5c), tetraploid (at least 10% of cells in the 4c region and a corresponding peak at 8c), and polyploid (multiple peaks in the 2c, 4c, 8c, and 10c regions). Of the 78 cases, 22 were diploid, 24 were intermediate, 29 were aneuploid, one was tetraploid, and two were polyploid. Histologic confirmation or clinical follow-up was found in 29 aneuploid cases, 13 intermediate cases, and one diploid case. Most cases of carcinoma in situ (five of six) and invasive tumors (12 of 17) were aneuploid. The sensitivity was 100%, and the specificity was 73% when cytologic and image analysis results were combined. We conclude that image analysis, when combined with cytologic examination, is a reliable noninvasive diagnostic test for monitoring patients with transitional cell carcinoma; aneuploidy is specific for malignancy; and the presence of cells greater than 5c, although frequently associated with tumor recurrence, can be seen in non-neoplastic conditions.

Adult↗

PubMed1998

Image analysis combined with visual cytology in the early detection of recurrent bladder carcinoma.

BACKGROUND: Early detection of recurrent transitional cell carcinoma of the bladder (TCC) is important to permit early treatment, which produces maximal preservation of the bladder and maximum survival. METHODS: This retrospective cohort study attempted to determine the period of time over which urinary DNA image analysis combined with visual cytology is useful in the early detection of recurrent TCC of the bladder. The authors believe this study is unique in that it measured the effectiveness of this test (image analysis plus visual cytology combined) at varying times before clinical diagnosis of recurrence was made. The cohort was comprised of 175 urologic patients from urologic practices across the U.S. Data, collected between January 1991 and February 1994, included cystoscopy, biopsy, DNA image analysis, and visual cytologic reports. RESULTS: Sixty patients in the cohort were found to have active TCC whereas 115 patients had a history of, but no active, disease during the follow-up period. As expected, the sensitivity and specificity of DNA image analysis in combination with visual cytology, and DNA image analysis alone, were greatest when urinary samples were obtained close to the time of diagnosis. In general, the longer the interval from the combined tests to the time of diagnosis, the lower the sensitivity. The combined tests had predictive value up to 3 months prior to clinical diagnosis when any detectable cytologic abnormality was considered positive. At the optimal cutoff points as determined from receiver operating characteristic curves, sensitivity increased when DNA image analysis was supplemented with visual cytology. CONCLUSIONS: The combination of DNA image analysis and visual cytology provides a better method for the early detection of recurrent TCC than DNA image analysis alone. This test potentially may be useful in providing information regarding bladder tumor recurrence up to 3 months prior to clinical evidence of disease.

Adult↗