X-ray diagnostic system for angiographic radiographs

• US 4,477,923 A
• Filed: 09/28/1982
• Issued: 10/16/1984
• Est. Priority Date: 02/03/1982
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Baumann, Heinz, Gerlach, Hans-Jurgen
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US06/425,315
• Time in Patent Office: 749 Days
• Field of Search: 378/95, 378/99, 378/8
• US Class Current: 378/95
• CPC Class Codes: A61B 6/481 involving the use of contrast agents
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition
• CPC Class Codes: A61B 6/504 for diagnosis of blood vessels, e.g. by angiography

Abstract

An exemplary embodiment comprises a patient support, an x-ray tube supplied by an x-ray generator, an x-ray image intensifier with a series connected television chain, a control loop for the controlling the mean image brightness, a syringe for contrast medium injection, and a program memory for storing several radiographic exposure programs. A time measuring device is present which is started by the syringe and is stopped by an evaluation unit when the mean image brightness varies to a predetermined extent. A computer calculates the contrast medium velocity from the measured time and the distance (x) between the injection location and the measuring location. On the basis of the calculated contrast medium velocity, an optimum program calculation, or program selection, respectively, is possible.

Claims

1. An x-ray diagnostic system for angiographic radiographs, comprising a patient support, an x-ray tube , arranged on one side of the support, an x-ray high voltage generator supplying said x-ray tube, an x-ray image intensifer, arranged on the other side of the support, a television chain connected with the x-ray image intensifier, a control loop for controlling the mean brightness, and a syringe for contrast medium injection, characterized by a time measuring means, capable of being started by the syringe, an evaluation unit coupled with the time measuring means and operable for signalling the time measuring means when the mean image brightness varies to a predetermined extent, and characterized by a computer means for the determination of the contrast medium velocity from the measured time and from the distance between the injection location and the measuring location.

2. An x-ray diagnostic system according to claim 1, characterized in that a program memory is present for storing several exposure programs and is controlled by the computer means in accordance with the calculated velocity for the purpose of automatic program selection, and that display means for the respectively selected program are present.

3. An x-ray diagnostic system for controlling angiographic imaging, said system comprising a patient support, an x-ray tube arranged on one side of the support, an x-ray tube supply circuit for supplying said x-ray tube, x-ray image sensing means arranged on the other side of the support for sensing an x-ray image produced by said x-ray tube at a sensing location, and having an output for supplying an output image signal having a mean image brightness, a control loop comprising a dose rate sensor coupled with the output of the x-ray image sensing means for sensing the mean image brightness of the output image signal, said control loop being coupled with said x-ray tube supply circuit to tend to maintain the mean image brightness of the output image signal constant during an imaging operation, syringe means for injecting contrast medium at a contrast medium injection location, time measuring means coupled with said syringe means for initiating a time measurement operation when a contrast medium is injected into a patient at a contrast medium injection location, an evaluation unit having an input coupled with said dose rate sensor and having an output controlling said time measuring means and serving to terminate a time measurement operation when the evaluation unit senses a transient in the output of said dose rate sensor due to the arrival of the contrast medium at the sensing location of said x-ray image sensing means to produce a resultant time measurement of the time measuring means serving to characterize the contrast medium velocity in conjunction with the distance between the contrast medium injection location and the sensing location of said x-ray image sensing means.

4. An x-ray diagnostic system according to claim 3, with said dose rate sensor comprising a photomultiplier.

5. An x-ray diagnostic system according to claim 3, with said control loop operating such that the mean image brightness as sensed by said dose rate sensor is momentarily reduced by at least about five percent when the contrast medium reaches the sensing location of said x-ray image sensing means.

6. An x-ray diagnostic system for controlling angiographic imaging, said system comprising a patient support, an x-ray tube arranged on one side of the support, an x-ray tube supply circuit for supplying said x-ray tube, x-ray image sensing means arranged on the other side of the support for sensing an x-ray image produced by said x-ray tube at a sensing location, and having an output for supplying an output image signal having a mean image brightness, a control loop comprising a dose rate sensor coupled with the output of the x-ray image sensing means for sensing the mean image brightness of the output image signal, said control loop being coupled with said x-ray tube supply circuit to tend to maintain the mean image brightness of the output image signal constant during an imaging operation, syringe means for injecting contrast medium at a contrast medium injection location, time measuring means coupled with said syringe means for initiating a time measurement operation when a contrast medium is injected into a patient at a contast medium injection location, an evaluation unit having an input coupled with the output image signal from the x-ray image sensing means and operative for sensing an abrupt change in the output image signal due to the arrival of the contrast medium at said sensing location of said x-ray image sensing means, said evaluation unit having an output controlling said time measuring means and serving to terminate a time measurement operation when the evaluation unit senses an abrupt change in the output image signal to produce a resultant time measurement serving to characterize the contrast medium velocity in conjunction with the distance between the contrast medium injection location and the sensing location of said x-ray image sensing means.