Computer-based cytophotometric classification of thyroid tumors in imprints

Quantitative automated image analysis system with automated debris filtering for the detection of breast carcinoma cells

OBJECTIVE

To develop an intraoperative method for margin status evaluation during breast conservation therapy (BCT) using an automated analysis of imprint cytology specimens.

STUDY DESIGN

Imprint cytology samples were prospectively taken from 47 patients undergoing either BCT or breast reduction surgery. Touch preparations from BCT patients were taken on cut sections through the tumor to generate positive margin controls. For breast reduction patients, slide imprints were taken at cuts through the center of excised tissue. Analysis results from the presented technique were compared against standard pathologic diagnosis. Slides were stained with cytokeratin and Hoechst, imaged with an automated fluorescent microscope, and analyzed with a fast algorithm to automate discrimination between epithelial cells and noncellular debris.

RESULTS

The accuracy of the automated analysis was 95% for identifying invasive cancers compared against final pathologic diagnosis. The overall sensitivity was 87% while specificity was 100% (no false positives). This is comparable to the best reported results from manual examination of intraoperative imprint cytology slides while reducing the need for direct input from a cytopathologist.

CONCLUSION

This work demonstrates a proof of concept for developing a highly accurate and automated system for the intraoperative evaluation of margin status to guide surgical decisions and lower positive margin rates.

Application of microscopic Forster resonance energy transfer to cytological diagnosis of the thyroid tumors

We propose a novel application of microscopic Forster resonance energy transfer (FRET) to clinical cytological diagnosis based on sensitive measurements of distance changes between fluorescently labeled deoxyribose nucleic acid (DNA) molecules. We have employed the microscopic FRET imaging for investigation of six papillary carcinomas and eight benign cases. In each case the FRET images of 20 cells stained by the AT-specific donor Hoechst 33258 and the GC-specific acceptor 7-aminoactinomycin D were acquired and analyzed by texture analysis. We have not found significant difference of the mean FRET efficiency between the benign and malignant groups. On the other hand, the texture analysis revealed a significant difference of the intranuclear spatial distribution of FRET efficiencies between the benign and malignant groups. The results indicate that despite the similar average distance between the AT- and the GC-rich DNA segments in the papillary carcinomas and the benign cases, the former has more heterogeneous distribution of the AT- and the GC-rich DNA segments in nuclei compared to the benign groups. We have demonstrated that the FRET imaging is a helpful tool for the medical cytological diagnosis of human tumors by giving information on the chromatin topology on the scale below the resolution of conventional optical microscopes. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

Morphological abstraction of thyroid tumor cell nuclei using morphometry with factor analysis

Various morphonuclear studies by digital image analysis have successfully been applied to quantify the nuclear morphology, including chromatin distribution pattern, in cytology of various organs; however, the majority of past reports have not shown correlation between the quantitative data by digital image analysis and cytological findings in practical diagnosis. In this report, we present the usefulness of morphological abstraction to combine the objective data and subjective observation in cytological diagnosis. Randomly selected, 100 cells in each Papanicolaou-stained ABC smear samples of 39 benign and malignant thyroid tumor cases were studied. Gray-level image data provided seven parameters for nuclear size, four parameters for nuclear shape, and 16 parameters showing the nuclear chromatin patterns from high-dimensional texture analysis of using co-occurrence and run-length matrices. To statistically abstract nuclear morphology, factor analysis was used. Factor analysis classified morphological nuclear characters as abstraction parameter into five abstract parameters composed of nuclear size, shape, heterogeneity, and contrast and homogeneity of chromatin pattern. The nuclei of papillary carcinoma showed larger size, more irregular shape, and higher contrast of chromatin pattern than those of the benign group. The follicular carcinomas have larger nucleus in each cell and more monotonous chromatin pattern among cells in each case than those of the benign group. Morphological abstraction by morphometry with factor analysis may provide a practical approach to the detection of the underlying characteristics of nuclear morphology in aspiration biopsy cytology.

Combined histomorphometric and gene-expression profiling applied to toxicology

We have developed a unique methodology for the combined analysis of histomorphometric and gene-expression profiles amenable to intensive data mining and multisample comparison for a comprehensive approach to toxicology. This hybrid technology, termed extensible morphometric relational gene-expression analysis (EMeRGE), is applied in a toxicological study of time-varied vehicle- and carbon-tetrachloride (CCl4)-treated rats, and demonstrates correlations between specific genes and tissue structures that can augment interpretation of biological observations and diagnosis.

Stereology, flow cytometry, and immunohistochemistry of follicular neoplasms of the thyroid gland

A retrospective analysis of surgically resected thyroid cold solitary nodules was performed by stereology, DNA flow cytometry, and immunohistochemistry in 15 follicular adenomas and 15 well-differentiated follicular carcinomas to determine if a differential diagnosis of both follicular neoplasms can be done exclusively from cytologic criteria. Between 150 and 200 tumor cell nuclei (TCN) were studied per case for their TCN profile area, perimeter, and density, as well as for stereologic estimates, including the new parameter, volume-weighted mean particle volume (Vv). Flow-cytometric analyses included measurement of the DNA index and the percentage of cells in S phase and G2M phase. The same tumors were examined for the expression of thyroglobulin and the intermediate filaments vimentin and keratin. Follicular adenomas and follicular carcinomas did not show any significant differences in stereologic estimates related to TCN size. Both groups included similar proportions of diploid and aneuploid neoplasms. Aneuploid follicular neoplasms showed a significantly greater area, perimeter, and volume of TCN as compared with diploid tumors, regardless of their histologic diagnosis. Follicular adenomas and follicular carcinomas expressed a similar staining pattern for the tested immunoreagents, with a few cases coexpressing vimentin and keratin. From our results, a differential diagnosis of follicular neoplasms cannot be performed on the basis of cytologic aspirates exclusively. Infiltration of capsula or vessels remains the only safe indicator of malignancy in the absence of metastases. The lack of cytologic differences suggests that some follicular adenomas are preinvasive carcinomas, not yet showing infiltrative growth at the time of resection.

[Differential diagnosis of follicular neoplasm of the thyroid]

Fifteen resected follicular adenomas and 15 well-differentiated follicular carcinomas of the thyroid gland were analysed to determine whether a differential diagnosis of both "follicular neoplasms" can be performed by cytological criteria exclusively. 150-200 tumor cell nuclei (TCN) were studied per case for their TCN profile area, perimeter, density and for stereological estimates including the new parameter Vv, volume-weighted mean particle volume. Flow-cytometric analyses included measurement of the DNA index, the percentage of cells in S-phase and in G2/M phase. Follicular adenomas and follicular carcinomas did not show any significant differences in stereological estimates related to TCN size. Both groups included similar proportions of diploid and aneuploid neoplasms. Aneuploid follicular neoplasms showed a significantly greater area, perimeter and volume of TCN as compared to diploid tumors, regardless of their histological diagnosis. From our results a differential diagnosis of follicular neoplasms cannot be performed on the basis of cytological aspirates exclusively. Infiltration of capsula or vessels remain the only safe indicators of malignancy in the absence of metastases. The lack of cytological differences provides evidence that some follicular adenomas are preinvasive carcinomas, not yet showing infiltrative growth at the time of resection.

An automatic analysis method for in situ hybridization using high-resolution image analysis

Specific mRNA for alpha 1 (I) collagen has been detected on a cellular level by in situ hybridization using radioactively labelled alpha 1 (I) antisense RNA probes. We here present an automatic, quantitative, evaluation technique for the determination of grain densities using the high-resolution image analysis system IPS KONTRON. The reliability and objectivity of this method were evaluated by comparing the values of grains per cell obtained by conventional and automatic techniques following in situ hybridization with alpha 1 (I) collagen DNA probes in various specimens. The correlation coefficients between conventional and automatic analysis of grain densities were 0.97 for fibroblasts embedded into a three-dimensional collagen gel, 0.94 for dermal fibroblasts in skin obtained from a patient with progressive systemic scleroderma, and 0.90 for fibroblasts in a 2-week-old scar. All correlation coefficients were significant on the P less than 0.0001 level. This new analysis technique therefore allows a more rapid and reliable quantitative evaluation of in situ hybridization and may also be helpful in differentiating between various cell populations characterized by different biosynthetic capacities.

Stereology and flow-cytometry of well-differentiated follicular neoplasms of the thyroid gland

A retrospective analysis of surgically resected thyroid nodules by stereology and DNA flow cytometry was performed in 15 follicular adenomas and 15 well-differentiated follicular carcinomas. The criteria for diagnosis were based on the WHO classification of thyroid tumours. By area-weighted random sampling of the visual fields for light-microscopic stereology, any subjective selection bias was precluded, and each point within the embedded neoplastic tissue was given equal probability of being analyzed. 150-250 tumour cell nucleus (TCN) profiles were studied per case by a semiautomatic image analyzing system. Flow cytometric analyses included measurement of the DNA-index, and the percentages of cells in S-phase and in G2/M-phase. Adenomas and carcinomas did not differ in stereological estimates related to TCN size. As examination of the stereological techniques by nested analysis of variance showed that this result cannot be ascribed to inaccurate methods, it follows that determination of TCN size is not a useful tool for the diagnosis of malignancy in well-differentiated thyroid tumours. Both groups included similar proportions of diploid and aneuploid neoplasms. In the carcinoma group the percentage of tumour cells in the G2/M-phase was more than twice as high than in the adenoma group (P less than 0.01). The ratio of short to long TCN profile axis was significantly smaller, and the coefficient of variation of TCN profile area was significantly higher in carcinomas than in adenomas. These findings are consistent with more unequiaxed TCN and higher anisokaryosis in the malignant tumours. Despite the significant differences, however, overlap of data from individual cases precludes the use of these estimates as diagnostic criteria. Pooling of the follicular tumours and dichotomizing the sample by the DNA-index showed that mean TCN profile area is increased and surface-to-volume ratio of TCN is decreased in aneuploid as compared to diploid tumours. This finding indicates that aneuploidy is associated with an increase of TCN size.