Matched filter for x-ray hybrid subtraction
US4542459A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 26, 1982 |
| Grant date | Sep 17, 1985 |
| Priority date | — |
| Expiry date | Nov 26, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S378/901
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Low and high energy x-ray exposures are made before and after an injected x-ray contrast medium arrives at a blood vessel of interest. In one mode, low and high energy mask images are made and these are subtracted from subsequent low and high energy images, respectively, to yield temporal difference images. The projected intensities of the contrast medium with respect to time constitute matched filter coefficients by which the difference images are mulitplied. The matched filtered images are summed, multiplied by weighting factors and subtracted from each other to yield a final hybrid image. In an alternative mode, successive pairs of low and high energy images are subtracted to yield energy difference images. The difference images are subjected to matched filtering and summed and the results subtracted to produce a final hybrid image. The matched filter coefficients are selected so the dc component in the image signal is equal to zero so everything that is constant in the initial series of images cancels out by subtraction and only contrast medium signal remains.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.