Apparatus and method for the analysis of retinal vessels
AssigneeIMEDOS GmbH
InventorsWalthard Vilser, Christine Kassner
Life of this patent
Estimating the term…
Abstract
The object of an apparatus and a method for the analysis of retinal vessels is to improve the reproducibility of individually determined artery-to-vein ratios and to reduce the measurement uncertainty in determining the artery-to-vein ratio in order to substantially increase the individual validity of the determined values for vessel diagnosis. At least two images are recorded successively as an image sequence in a predetermined timed sequence adapted to the vasomotricity of the vessels and are evaluated such that a mean artery-to-vein ratio is formed from artery-to-vein ratios that are determined on the basis of the at least two images.
Claims25
An apparatus for the analysis of retinal vessels comprising:
- a retinal camera for recording images of the ocular fundus;
- at least one image storage;
- means for detecting arterial and venous vessels in the images;
- means for determining the vessel diameters of the detected arterial and venous vessels;
- means for determining artery-to-vein ratios from the determined vessel diameters;
- said retinal camera being connected to an image sequence control unit which carries out a control of the time intervals or times which is adapted to the period of vasomotor waves and a control of the quantity of images of a sequence of images to be recorded for which an image sequence storage is provided for storing images;
- and
- said means for determining artery-to-vein ratios being designed to determine a mean artery-to-vein ratio from artery-to-vein ratios which are determined from at least two images of an image sequence.
A method for the analysis of retinal vessels comprising the steps of:
- evaluating digital fundus images in which a ring-shaped measurement zone containing vessel portions which proceed from a central vessel, which are to be distinguished as arteries or veins, and which are to be measured;
- arranging said measurement zone around the papilla at a distance therefrom;
- determining a vessel diameter for each of these vessel portions;
- determining a retinal arterial vessel diameter equivalent and a retinal venous vessel diameter equivalent from the determined vessel diameters of the arterial and venous vessel portions;
- determining an artery-to-vein ratio is determined from the vessel diameter equivalents of the arteries and veins;
- recording at least two images, as fundus images to be evaluated, successively in a timed sequence that is adapted to the period of vasomotor waves as an image sequence;
- and
- forming a mean artery-to-vein ratio from artery-to-vein ratios that are determined based on the at least two images.
Dependencies are inferred from the claim text.