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Biomedical subjects

F Potente

Publications and source records attributed to F Potente.

16 recordsLinked to original sources

Biological image analysis for microscopical diagnosis: the work-station S.A.M. (Shape Analytical Morphometry).

The S.A.M. (Shape Analytical Morphometry) software system and its related work-station give a generalized and easy-to-handle tool to face a classic and intriguing problem in biomedical morphological diagnosis. What is the shape of an object in a microscopic image? How can we understand the relationship between size and shape? According to Holloway: "Measurements such as length, width, height, whether in chords or arcs only describe space, ... and further run into the abyss of allometric correction ... if additional information (shape?) to size is expected, some method of allometric correction must be used." The S.A.M. software system assumes a logic architecture able to separate and to parametrize independently shape characteristics in terms of allometry and local pertubation by analytical procedures (polynomials, parabolic fitting, Fourier analysis) in addition to the classic evaluations of size and density carried out by image analyzers for microscopical diagnosis.

Diagnosis, Computer-Assisted

Analytical morphometry of sagittal fronto-facial profiles of 2nd-6th month human foetus.

A prominent problem in the morphological study of developing biological structures is shape parametrization with the aim to evaluate transformations in a non subjective way. We carried out an analytical morphometrical study on a series of human embryos, by means of the S.A.M. (Shape Analytical Morphometry) software package. After standardization and normalization of the fronto-facial sagittal profiles, the analytical procedures applied were: 1) Fourier analysis: each profile was considered as an irregular but periodic function obtained by the sum of sinusoids of increasing order. 2) Shape Asymmetry Evaluation: couples of profiles are compared by means of "Janus" procedure; by a parabolic fitting we obtained parameters able to evaluate allometric and isometric differences between the two profiles. The preliminary results of the applied procedures indicated that rate and direction of allometric and isometric growth are not constant during the time.

Fetus

Using analytical morphometry to distinguish severe dysplasia and large bowel carcinoma.

The aim of the present paper is to find analytical parameters to distinguish severe dysplasia from cancer. A population of 150 nuclei was selected randomly from: 5 cases of large bowel carcinoma, 5 cases of adenomatous polyps with severe dysplasia--according to Kozuka's criteria--(without any reference to the architecture: tubular, tubulo-villous and villous) and 5 cases of normal mucosa as control. The files of the coordinates of the nuclear contours were submitted to the S.A.M. (Shape Analytical Morphometry) work-station, which produces quantitative parameters (area, perimeter, maximum diameter and Roundness Factor) as well as analytical shape-descriptors. The latter were extracted by the S.A.E. (Shape Asymmetry Evaluator) procedure, which evaluates the symmetry of each contour studied, and by Fourier harmonic analysis which breaks up each curve into a defined set of harmonics which are then used to perform statistical tests. In the comparison between normal and severe dysplastic nuclei, normal and carcinomatous nuclei and severe dysplastic and carcinomatous nuclei univariate statistical evaluation (Student t test) proved to be highly significant for the most of the analytical parameters.

Biometry

[Quantitative evaluation of the allometric transformation of of biological structures].

Detection and quantification of allometry is a crucial problem in understanding morphological changes, both for systematic and morphogenetic purposes. A section of S.A.M. (Shape Analytical Morphometry) software system was used for this attempt. It consists of the following steps: a) boundary detection; b) starting point detection; c) size normalization; d) extraction of the fundamental shape by Kth order polynomials; e) finding of symmetry evaluator (S.A.E.) by means of a second degree equation. This last procedure gives an arc-chord complex that expresses a vector for allometry where intercept value was for application point, first degree coefficient was for direction and second degree coefficient was for modulus and versus. The main parameters, isometry fraction and allometry fraction may be understood referring them to morphogenetic models.

Algorithms

[Evaluation of skull vault asymmetry using methods of analytical morphometry].

Some vertical frontal C.A.T. sections of 8 skull vaults were studied in evaluating shape asymmetry between left and right curves. Every profile was normalized by subdividing in 120 points and standardized by positioning the sagittal line of skull vault profile parallel to the ordinate axis of a Cartesian system. After these procedures, we tried to detect the asymmetry. In order to achieve these results we used a procedure that we named "Janus", a subset of S.A.M. (Shape Analytical Morphometry) software system, giving an artificial close curve by the mirror composition of left and right cranial vault profiles to match each other. This match was performed by a parabolic fitting for a standard positioning. The procedure was able to split the whole asymmetry information into the isometric and allometric components. We tried to detect allometry in terms of direction and versus with a numerical evaluator of its magnitude; this description was properly a vector. In this pilot study by using 24 sections, we found 20 left and 4 right predominance, expressed time by time by isometry, allometry or both.

Adult

Differential diagnosis between thyroid follicular adenoma and carcinoma. Analytic morphometric approach.

In this study some nuclear dimensional and analytical parameters were evaluated in order to distinguish follicular atypical adenoma from follicular carcinoma of the thyroid. Eighty nuclei from carcinomas, 80 from adenomas and 80 from normal thyroid were studied. Analytical parameters obtained by the nuclear shape study (by S.A.M. system) as well as dimensional parameters were submitted to univariate statistical analysis. On the ground of our results atypical adenoma could be considered as an intermediate aspect of a progressive change from benign to malignant even if they are closer to normal thyroid than to carcinoma.

Adenocarcinoma

Prognostic value of CEA and ferritin assay in breast cancer: a multivariate analysis.

The prognostic significance of preoperative serum carcinoembryonic antigen (CEA) and ferritin levels was evaluated in 191 women operated for breast cancer. The influence of CEA, ferritin and another 11 clinical and pathological features on the disease-free survival was investigated in a multivariate analysis, using Cox's proportional hazard model. Axillary node status (P = 0.004), CEA level (P = 0.011), and the histological grade of the tumor (P = 0.029) emerged as independent prognostic factors. By contrast, no significant relationship was found between ferritin and disease-free survival. These three parameters were used to derive a prognostic index (I) for each patient. Multivariate analysis showed that its prognostic value was better than the value of any single factor (P less than 0.0001). The I score was used to divide patients into groups at different risk of recurrence: low, moderate and high (97.5%, 45% and 22.5% of recurrence-free patients at 3 years respectively). The data showed that the prognosis of patients with different combinations of node status and tumor grade was related to the level of CEA. Only women with very good (node-negative with well-differentiated tumors) or very bad prognosis (node-positive with four or more metastatic nodes and poorly differentiated tumors) had a disease-free survival independent of CEA values. These findings suggest that the preoperative measurement of CEA enhances the possibility of correctly predicting outcome and hence could be of assistance in the planning of adjuvant therapies.

Adult

Computer-aided skull/face superimposition.

By use of a special optical device coupled with a TV camera to match a skull and a photograph of a face, superimposition for the purpose of personal identification was performed in controlled situations. A computer-aided method to evaluate the fit of the superimposition has been outlined by means of an original Shape Analytical Morphometry (SAM) software package yielding analytical descriptions by kth-order poly-nominal equations and Fourier harmonic analysis. The match was carried out by using point-cross error and sum of differences for the Fourier set amplitude. A final comprehensive evaluation exhibited marked differences between congruent and noncongruent superimpositions.

Face

[Parameters of analytic morphometry: proposal for a symmetry evaluator].

A morphometrical analytical evaluator of asymmetries of biological structures bonded by a closed curve was suggested. A second degree equation couple was found in order to detect, respectively according X and Y axis, first main asymmetry whereas third degree equation revealed first and second asymmetry for both abscissa and ordinate values. Final evaluator, named S.A.E. (Shape Analytical Evaluator), was computed as arch/cord ratio between function curve and its cord, it was equal to 1 for circles and any ellipse and symmetrical shapes whereas it was of different value for asymmetrical shapes.

Anthropometry