Digital subtraction fluorographic method and apparatus
US4633307A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 5, 1985 |
| Grant date | Dec 30, 1986 |
| Priority date | — |
| Expiry date | Sep 5, 2005 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B6/504
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
In a digital intravenous subtraction fluorographic system, X-ray subtraction images obtained by performing a subtraction between the precontrast images and the post-contrast images are processed by comparing, for each pixel, the value of the pixel image data in the difference image with a predetermined threshold intensity value, and recognizing the time until the value of the pixel image data reaches the threshold intensity value. The resulting time data so determined in the processor is used for displaying the distribution of contrast medium in the vessel in relation to the time periods it takes for each pixel to attain the predetermined threshold intensity. In effect, the time data for each pixel is itself converted to an intensity signal dependent on the amount of time it takes for each pixel to cross the predetermined threshold intensity, and it is the time period derived intensity signal which is displayed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.