Prognostic significance of DNA cytometry in thymoma.

PURPOSE: The aim of this work was to evaluate the prognostic significance of DNA image cytometry in thymoma. PATIENTS AND METHODS: Image cytometric studies with an automatic video-based analysis system (LEYTAS) were carried out on 47 archival specimens from 36 patients with thymomas who underwent operation at a single institution from 1954 to 1992. The significance of aneuploidy DNA-content (5c-exceeding events), and nuclear size on stage and survival were evaluated. The median follow-up was 52.7 (6-164) months. RESULTS: Masaoka's stage was predictive of aneuploidy (P < 0.01) and disease-free survival (P < 0.015). In stage I 18% of the tumors were aneuploid, in stage II 78%, in stage III 85% and in stage IV 100%. The occurrence of 5c-exceeding events was associated with both decreased disease-free survival (P < 0.01) and overall survival (P = 0.013). Nuclear size was not significantly correlated to stage. Under multivariate analysis, aneuploidy and DNA content failed to attain independent significance for stage, performance status, and histology. CONCLUSION: DNA image cytometry may provide additional information about the prognosis of resected thymoma.

The suitability of DNA cytometry for the prediction of the histological diagnosis in women with abnormal cervical smears.

OBJECTIVE: To analyse the suitability of DNA cytometry for predicting the histological diagnosis in women with cervical dyskaryosis. DESIGN: Survey with the use of diagnostic information to revise disease probability. SETTING: Colposcopy clinic of a university hospital. PARTICIPANTS: One hundred and ten women with two mildly or moderately dyskaryotic cervical smears and 98 women with one severely dyskaryotic smear. INTERVENTIONS: DNA cytometric analysis using cytocentrifuge preparations of single cell suspensions from a cervical scrape. The main DNA cytometric parameter was N5C (i.e. the absolute number of cells with a DNA content of more than 5C on a given surface with a predefined cell density). MAIN OUTCOME MEASURE: The probability of finding CIN II or worse. On arbitrary grounds, a positive test should point to a probability of 85% or higher. RESULTS: In the patients with cervical neoplasia, the value of N5C increased significantly with an increasing CIN grade (P < 0.001). In the patients with one severely dyskaryotic smear and in those with two mildly or moderately dyskaryotic smears, the prior probability of finding CIN II or worse was 94% and 53%, respectively. Therefore, DNA cytometric analysis might be particularly useful in women with mild or moderate dyskaryosis; further analysis was restricted to this group. All of the women in whom the N5C value was higher than 52 were diagnosed as having CIN II or worse. Only 16 (14.5%) of the 110 women had an N5C value of 52 or higher. When the N5C value was 27, the probability of finding CIN II or worse was estimated to be 85%. Only 28 (25%) patients had an N5C value of 27 or higher. CONCLUSIONS: DNA cytometry produced significant diagnostic information, as was shown by the relation between N5C and the histological diagnosis. However, the N5C value could not discriminate sufficiently between women with CIN II or worse and CIN I or better. Therefore, the management of individual patients with cytological abnormalities cannot be based on the results of DNA cytometric analysis.

Detection improvement of cytomegalovirus antigen in human peripheral blood using monoclonal antibodies and automated reading of cell preparations.

One of the major drawbacks in cytomegalovirus (CMV)-antigenaemia detection for diagnosis of active CMV infection is the low number of CMV-antigen positive cells present in peripheral blood. It is therefore necessary to screen large numbers of peripheral blood granulocytes to find only a few antigen-positive cells. We have optimized this detection by testing several monoclonal antibodies (mAb) to CMV-antigens (mAbs C10/C11, C12, BM222, E13 and SL20). In total 550 blood samples from 40 patients were investigated. More blood samples were found positive with mAb C12 than with the other mAbs. Also the average number of positive cells per slide was highest for mAb C12. Furthermore, duplicate slides were examined automatically using an image analysis system (LEYTAS) and compared to visual detection (cytospin slides). The detection sensitivity of both screening methods was compared for mAb C12. In total 360 slides were analysed, from positive as well as negative blood samples. The sensitivity of the automated screening was 93% and for the visual evaluation of the cytospin slides 73%. In conclusion, mAb C12 was the most suitable of the mAbs tested for detection of antigenaemia, and automatic detection of CMV antigenaemia with image analysis of slides is a sensitive method due to the large numbers of cells that can be screened.

Automated screening for cytomegalovirus infected cells using image analysis. Comparison of two immunoenzymatic staining methods with respect to colour segmentation.

The detection of human cytomegalovirus (HCMV) infected poly-morphonuclear leukocytes (PMNLs) for early finding of the pp65 antigen using automated image analysis has been improved. The routinely used immunoenzyme peroxidase (PO) labelling has been replaced by alkaline phosphatase (AP) using new fuchsin as substrate. The number of automatically detected false positive objects due to incomplete inactivation of endogenous peroxidase and strong variations in counterstain intensity could be reduced by 81% using this AP staining method. The number of detected truly positive cells with both staining methods was not significantly different. Furthermore, a new image analysis system providing processing of colour images was evaluated. Since plain differences in absorption wavelength are required for colour segmentation, the red immuno-staining was combined with a green counterstain using methyl green. Screening of AP- instead of PO-stained slides in combination with colour segmentation resulted in a further reduction of the number of falsely detected alarms from 61% to 11%. Consequently, the sensitivity of the automated detection was improved. For AP staining detection of cells in frequencies of approximately one to one million was demonstrated. Screening for CMV-positive, alkaline phosphatase labelled cells using an image analysis system with colour segmentation resulted in a reduced false alarm rate, a better visual interpretation of the images and subsequently an increase in the sensitivity of the automated screening process.

Quantification of low frequency white blood cells expressing human cytomegalovirus antigen by image cytometry.

Human cytomegalovirus (HCMV) infections cause considerable morbidity and mortality in immunocompromised patients. During HCMV infection, leukocytes appear in the circulation in low frequencies that express the HCMV pp65 protein antigen. Since there is evidence that changes in the frequency of antigen-positive cells in the early phase of the infection have prognostic value, we applied automated image cytometry to quantify these antigen-positive cells. For this purpose weekly peripheral blood leukocyte samples of 80 kidney transplant recipients were visually examined for the presence of antigen-positive cells using an immunocytochemical detection method. Seventeen patients, who reacted positive with this assay, were identified. Next, automated image cytometry was applied to quantitate the frequency of antigen-positive cells in sequential blood samples from the 17 patients. Patients who developed a period of HCMV viremia had a significantly longer antigenemic period and a significantly higher frequency of antigen-positive cells than patients with a HCMV infection who remained nonviremic. Therefore, automated image immunocytometry based screening can be used to distinguish patients at risk for the development of a HCMV viremia. Moreover, automated quantitation reveals prognostic information about the HCMV infection at a more sensitive level than other HCMV detection techniques.

Automated image cytometry for detection of rare, viral antigen-positive cells in peripheral blood.

A cell detection method based upon automated screening is described for recognition of low frequencies (1 in 100,000) of immuno-enzymatically labelled white blood cells in human peripheral blood. The used image cytometry instrumentation (LEYTAS) includes a wide-field, fully automated microscope (Autoplan) and a modular image analysis computer (MIAC), both from Leica, Wetzlar, Germany. The MIAC contains image boards for optimum use of mathematical morphology algorithms. Communication with the MIAC is via a personal computer. Programs for automated cell analysis have been written in C language. Main features of the system are fast analysis of large microscope fields including a count of all cells, selection of objects of interest (alarms), and display of digitally stored images of these alarms. We tested this system for the detection of white blood cells expressing antigen of cytomegalovirus (pp65) in 50 human blood smears from kidney transplant recipients. Immuno-enzymatic (peroxidase) staining was performed with DAB and counterstaining with hematoxylin. For determination of the sensitivity, a series of dilutions of a positive sample with a negative sample was performed. The lowest frequency detected was 1 antigen-positive cell/3 x 10(5) antigen-negative cells. Screening time was about 60 min for one million cells.

Prognostic significance of cell DNA content in early-stage ovarian cancer (FIGO stages I and II/A) by means of automatic image cytometry.

Paraffin-embedded material from 69 patients with epithelial ovarian cancer FIGO stages I and II/A (including 21 patients with borderline carcinoma) was studied with automatic DNA image cytometry. Univariate analysis indicated a significant difference in survival based on the presence of nuclei with high DNA content (higher than 5 C). A group of patients with less than 0.2% cells with high DNA content had a 6-year survival of 87%, whereas in a group of patients with more than 0.2% of such cells, 6-year survival was 49%. This parameter remained significant when used in a group of stage I/a and I/b patients. Statistical analysis of diploid vs. non-diploid tumors also showed significant difference in survival. Separate analysis of 48 invasive ovarian cancers indicated that ploidy, the percentage of cells with high DNA content and tumor stage (stage I/a + b vs. stages I/c + II/a) reached significance for survival, whereas grading did not. In addition, comparison of clinical stage, grading, ploidy and the percentage of cells exceeding 5 C with a threshold at 0.2% by means of a multivariate analysis (Cox regression model) showed that only the percentage of cells exceeding 5 C remained statistically significant.

High DNA content and prognosis in lymph node positive breast cancer. A case control study by the University of Leiden and ECOG. (Eastern Cooperative Oncology Group).

To investigate whether breast cancer cells with unusually high nuclear DNA content are associated with an adverse outcome, Eastern Cooperative Oncology Group investigators selected breast cancer trial patients who suffered an early death (ED) within two years after diagnosis to compare with other trial patients who had a survival of at least 7.5 years. Paraffin blocks of primary breast cancers were obtained from 93 evaluable patients who had been enrolled in two surgical adjuvant trials for lymph node positive (LN+) disease (T1-3N1M0). Single cell monolayer preparations from these blocks were stained with acriflavine-Feulgen and analyzed by image analysis for DNA content with the automated Leiden Television Analysis System (LEY-TAS). Standard prognostic variables (estrogen receptor (ER) status, number of lymph nodes with metastases, and size of the cancer) were compared with three DNA content characteristics: DNA ploidy status, number of nuclei with > 5C DNA content, and percent of nuclei with > 5 C. Estimates of the odds ratio in multivariate comparisons showed that ER negativity was associated with ED (p = 0.0005) and an odds ratio estimate using negative/positive of 4.87. The number of positive lymph nodes associated with ED had a p-value of 0.0005 and an odds ratio estimate of 4.63 when comparing the > 3 nodes group to the 1-3 nodes group. In contrast, the strongest association for any of the DNA content characteristics with ED had a p-value of 0.017 and an odds ratio estimate of 2.76. This power of association disappeared when stratified on ER status.(ABSTRACT TRUNCATED AT 250 WORDS)

Image cytometric DNA analysis in transitional cell carcinoma of the bladder.

BACKGROUND: The current study was initiated to investigate measurable objective and reproducible characteristics that might have prognostic significance in bladder cancer. METHODS: Tumor samples from 91 patients with primary transitional cell carcinoma (TCC) of the urinary bladder were studied by DNA image cytometry and cytogenetic analysis. Image cytometry is a more sensitive method of determining ploidy than flow cytometry, especially in tumors with a low number of aneuploid cells. RESULTS: There was a significant difference in survival between DNA image cytometry-determined diploid and nondiploid cases. The presence of nuclei with a high DNA content indicated poor prognosis. The 2C deviation index (2CDI) also was an indicator of survival. Image cytometry-determined factors also were found to be strong predictors of progression-free survival. In multivariate analysis, 2CDI was the only cytometric parameter with an independent but weak correlation with survival. In multivariate analysis, none of the cytometric parameters had an important contribution to prediction of progression-free survival. In superficial tumors (Ta and T1), 2CDI appeared to be the most important independent predictor of survival. With respect to progression-free survival, tumors with a high mitotic index proved to have a worse prognosis. CONCLUSIONS: Parameters determined by DNA image cytometry appear to be valuable in predicting survival and progression-free survival and may be useful in addition to the classic parameters of stage and grade, especially in superficial TCC.

Automated cell analysis for DNA studies of large cell populations using the LEYTAS image cytometry system.

Image cytometry by means of LEYTAS features analysis of both fresh and archival cellular material. Although not as accurate in ploidy determination as flow cytometry, LEYTAS cytometry incorporates extensive artefact rejection algorithms, thereby allowing detection of low frequency cells. This feature is very useful for the search of rare cells, as e.g. in cervical screening, or for the quantitation of the number of high DNA content cells in the total cell sample. LEYTAS main components are an automated microscope (Autoplan) and a Modular Image Analysis Computer (MIAC), both from Wild Leitz (W-Germany). This paper discusses LEYTAS instrumentation and cell analysis by means of programs especially written for LEYTAS.

Image cytometry in automated cervical screening.

Severe restrictions with regard to false negative rates have played a major role in the development of the LEYden Television Analysis System (LEYTAS). The present paper describes a test with a continuous series of 1500 cervical samples illustrating the accuracy of LEYTAS in a fully automated screening procedure using cell selection transformations and artefact rejection procedures. Specimen classification with a cut-off at greater than 0.3% alarms (= percentage of automatically selected objects per epithelial cells) and greater than 10 alarms, results in a false negative rate (FNR) of 0.3% (1 case out of 321 cases with severe dysplasia or more serious lesions), a false positive rate (FPR) of 13% (663 negative cases) and a rejection rate of 2.7%. Besides a machine classification, LEYTAS offers a second, machine-interaction classification of those preparations which have been declared positive by the machine. Machine-interaction involves visual evaluation of the stored images of the detected objects (alarms) and reduces the FPR from 13 to 8%. Statistical tests further demonstrate the significance of the screening results. Presently the main drawback for routine use of automated screening with LEYTAS seems to be the time consuming preparation procedure, since instrumentation has now been updated to a new, fast and user-friendly version of LEYTAS.

Use of DNA image cytometry in addition to flow cytometry for the study of patients with advanced ovarian cancer.

Forty-five patients with advanced ovarian cancer were studied with both DNA flow cytometry (FCM) and automatic DNA image cytometry carried out with the Leiden Television Analysis System (Leytas). There was a significant difference in survival between the diploid and nondiploid cases as determined by FCM. Furthermore, the presence of nuclei with a high DNA content (defined as a DNA content higher than 5C) as determined by Leytas indicated a poor prognosis. When the combined results of FCM and Leytas were taken into account, three different groups of patients could be distinguished. The group of patients with a diploid malignancy (n = 12) had a median survival of more than 60 months. The group of patients (n = 11) with a nondiploid tumor having fewer than 100 nuclei with a high DNA content per 1600 microscope fields formed an intermediate group (median survival, 42 months), whereas the median survival of the remaining patients (n = 22), who had a nondiploid malignancy combined with more than 100 of these nuclei per 1600 microscope fields, was only 15 months. In addition, comparison of the clinical parameters by means of a multivariate analysis (Cox regression model) showed that the combined results of FCM and DNA image cytometry had the largest influence on survival. It is concluded that DNA image cytometry appears to be supplementary to FCM for the study of DNA ploidy abnormalities and that the combined results of these methods have a major influence on the clinical outcome.

Image analysis combined with quantitative cytochemistry. Results and instrumental developments for cancer diagnosis.

This paper describes the application of image analysis combined with a quantitative staining method for the analysis of cervical specimens. The image analysis is carried out with the Leyden Television Analysis System, LEYTAS, of which two versions are described. LEYTAS-1 as well as LEYTAS-2 have both been designed with a high degree of flexibility and interaction facilities. A much wider range of image analysis programs is however, possible with LEYTAS-2, enabling many applications. LEYTAS-1, the earlier version, consists of a Leitz microscope with automated functions, a TV camera, the Texture Analysis System (TAS, Leitz), a four-bit grey value memory and a minicomputer (PDP 11/23). Using this instrumentation 1,500 cervical smears prepared from cell suspensions and stained with acriflavin-Feulgen-Sits have been analysed in a completely automated procedure. Image transformations working in parallel on entire fields, have been used for cell selection and artefact rejection. Resulting alarms, consisting of selected single cells and non-rejected artefacts are stored in the grey value memory, which is displayed on a TV monitor. This option allows visual interaction after the machine diagnosis has been made. The machine diagnosis was correct in 320 out 321 specimens with a severe dysplasia or more serious lesion. The false positive rate in 561 morphologically negative specimens (normal and inflammation) was 16% (machine diagnosis). Visual interaction by subtracting the visually recognized false alarms from the total number of alarms reduces the false positive rate to 11%.(ABSTRACT TRUNCATED AT 250 WORDS)

LEYTAS analysis of cytological specimens: the results of thousand cervical smears.

This paper describes the application of a television-based system (LEYTAS) in machine analysis of cervical specimens. LEYTAS basically consists of a Leitz microscope, the texture analysis system (TAS, Leitz), a TV camera, a 4-bit grey value memory and a minicomputer (PDP 11/23). A series of 1176 Feulgen stained cervical smears has been analysed in an automated procedure using image transformation for cell selection and artefact rejection. During the analysis of the entire series new artefact rejection procedures have been added to the automated analysis. This addition decreased the percentage of false positives to 15% in the last 277 analysed smears. This percentage concerns machine performance alone. A rapid visual interaction procedure decreases this percentage to 9%. Out of 210 morphologically positive smears (diagnosis Papanicolaou class 3b or more) from the total series, one smear was missed by LEYTAS using the machine classification.

A preparation technique for exfoliated and aspirated cells allowing different staining procedures.

Quantitative cytology requires highly standardized preparation, fixation and staining techniques in order to obtain reproducible morphology (e.g., cell size, cell shape and chromatin distribution). We found centrifugal cytology best suited to this purpose. Therefore, we recently developed an improved bucket for centrifugation that permits sedimentation of cells in a fixative solution (2% polyethylene glycol in 50% ethanol) by using centrifugation at relatively high g forces. The cell quantity, the cell distribution and the flatness of the specimens thus prepared proved to be adequate for automated anlysis using the Leyden Television Analysis System (LEYTAS). Furthermore, different cytochemical and cytomorphologic staining procedures could be performed on different aliquots of the same cytologic sample without any change in the preparation or fixation technique.