Showing papers on "Parametric Image published in 1992"
01 Jun 1992
TL;DR: Preliminary validation has been undertaken using parametric images generated in two ways: synthesis from a computer model of vascular pulsatile flow and analysis of cine-angiograms of physical models carrying known pulsatile flows.
Abstract: The principles and implementation of a method for measurement of blood flow waveforms from X-ray angiography are described. Contrast medium mass values are obtained at multitudinous positions along individual vessels and from numerous images in a time sequence. These values are represented as a matrix of grey levels in a parametric image. This image is normalized to represent contrast medium concentration, and the movement over time of isoconcentration portions of the contrast bolus is recovered to determine blood flow. Preliminary validation has been undertaken using parametric images generated in two ways: synthesis from a computer model of vascular pulsatile flow and analysis of cine-angiograms of physical models (plastic and perspex tubes) carrying known pulsatile flows. Two distinct methods for interrogation of parametric images by digital image processing were employed; both provided accurate flow measurements.
15 citations
11 Oct 1992
TL;DR: In this article, a set of angiographically acquired images of steady control flows in constricted and unconstricted Plexiglas models and in a human coronary bypass graft was acquired.
Abstract: A set of angiographically acquired images of steady control flows in constricted and unconstricted Plexiglas models and in a human coronary bypass graft was acquired. A set of flow sensitive parametric images was derived from those sequences. The Plexiglas arterial model (phantom) was designed specifically for this study. The parametric images were calculated using the contrast density curves obtained at each pixel in a region of interest in a sequence of angiographically acquired images. The calculated parameters described are a contrast velocity image derived from the slope of the contrast density curve, and an arrival time image of the contrast bolus. A numerical simulation of the contrast flows in the Plexiglas phantoms was also conducted and a synthetic arrival time parametric image was calculated which qualitatively validates the experimental results. This study indicates that parametric images offer an efficient means of identifying regions of recirculation and jetting velocity for the steady flow of Newtonian fluids examined, and may be of diagnostic value in the assessment of human vessels. >
2 citations