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Biomedical subjects

P A Briandet

Publications and source records attributed to P A Briandet.

5 recordsLinked to original sources
PubMed1987

Two-dimensional mapping of three-dimensional SPECT data: a preliminary step to the quantitation of thallium myocardial perfusion single photon emission tomography.

A method is presented by which tomographic myocardial perfusion data are prepared for quantitative analysis. The method is characterized by an interrogation of the original data, which results in a size and shape normalization. The method is analogous to the circumferential profile methods used in planar scintigraphy but requires a polar-to-cartesian transformation from three to two dimensions. As was the case in the planar situation, centering and reorientation are explicit. The degree of data reduction is evaluated by reconstructing "idealized" three-dimensional data from the two-dimensional sampling vectors. The method differs from previously described approaches by the absence in the resulting vector of a coordinate reflecting cartesian coordinate in the original data (slice number).

Coronary Circulation↗
PubMed1986

Interrogation and display of single photon emission tomography data as inherently volume data.

The purpose of single photon emission computed tomography (SPECT) data is to map the tracer concentration from the three-dimensional object into a three-dimensional image array. The conventional interrogation of the data is through slice interrogation. In this paper we explore display methods in which the data are directly interrogated and processed as three-dimensional data. This includes direct addressing of sagittal, transverse, and frontal slices, around a targeted subvolume, and direct addressing of nonorthogonal slices. The three-dimensional aspect of the data is further accommodated by thresholding and edge definition in space. Finally, morphological information, which is sparse in scintigraphic slices, is recaptured by the generation of planar data derived from data processed in the three-dimensional space.

Data Display↗
PubMed1981

A fully automated determination of the left ventricular region of interest in nuclear angiocardiography.

The precise delineation of the left ventricular projection area is an essential part in the quantitative analysis of nuclear angiocardiograms. We have devised an algorithm that permits automation of this step, based on a one-dimensional Laplace operator whose kernel is 2, 2, -2, -4, -2, 2, 2. The operator characteristically enhances "valleys" more than edges and, therefore, favors septal and the valve plane detection. The operator is applied vertically, horizontally, and along both diagonals. Each pass is immediately followed by a local maximum search during which the image resulting from the Laplacian operator is reduced to a binary one, with zeros everywhere except where a local maximum was found along the path of the operator. This resultant image yields a closed "edge" around the left ventricle, even though many structures outside the left ventricle are also delineated. However, the centroid of the ventricle is defined from functional criteria and the region of interest is defined from centroid to first edge. The method has been applied to first-pass and gated studies in anterior and 45 degree left anterior oblique views. In 100 successive cases the ejection fraction obtained automatically was compared to the manual result. The regression equation yielded the relation: automatic method (%) = 1.7 + 1.0 manual method (%) +/-2% (r = 0.995), which is not significantly different from the identity relation. The failure rate was low (13%) but varied from 28% in the first-pass studies in the anterior view, to less than 8% in gated studies in the left ventricular oblique projection.

Cardiac Volume↗
PubMedDate not supplied

A thresholding for radionuclide angiocardiography.

A thresholding algorithm for nuclear angiocardiographic studies is presented. The algorithm is free of operator intervention. The threshold is defined on the basis of the distribution of picture elements with decreasing count rates during systole. The application is valid for first-pass and equilibrium ECG gated studies. Reproducibility by different operators with various degrees of experience is high; concordance of the results with those of contrast studies is within the published ranges. The method provides a reliable step in full automation and standardization of scintigraphic angiocardiographies.

Heart↗