Device and method for producing images of the heart
The invention relates to a device and a method for producing an image of the heart ( 5 ), in which the image is preferably three-dimensional and is reconstructed from a series of X-ray projection pictures from various projection directions. In this connection, the electrocardiogram ( 7 ) is recorded in parallel with the X-ray pictures and used by a data processing device ( 10 ) to control the picture-taking rate, the X-ray pulse duration, the tube current and/or the tube voltage of the X-ray device ( 1 ) in such a way that, during the phase to be displayed of maximum movement of the heart, the mean X-ray exposure rate is higher than during the other phases. The data processing device ( 10 ) may furthermore use the electrocardiogram to drive an injection pump ( 8 ) for the contrast agent in such a way that an approximately constant contrast display of the vessels is produced with minimum contrast-agent injection despite a variable flowrate in the vascular system.
1. A device for producing images of an object that is subject to a cyclic spontaneous movement and for controlling an injection rate of a contrast agent in a vascular system of the object, comprising:
a) an X-ray unit for producing a series of two-dimensional projected pictures of the object;
b) a measuring device for determining a parameter characteristic of the spontaneous movement of the object;
c) a data processing device that is coupled to the X-ray unit and the measuring device and that is designed to drive the X-ray unit as a function of a particular value of the spontaneous movement characteristic parameter in such a way that, during a predetermined movement phase to be displayed corresponding to a movement phase of greatest movement, pictures are taken of the object with a higher X-ray exposure rate and/or picture-taking rate than during the other movement phases;
d) an injection pump for injecting the contrast agent at a controllable injection rate;
e) a measuring device for determining a parameter characteristic of a flowrate in the vascular system; and
f) a control unit that is coupled to the injection pump and the flowrate parameter characteristic measuring device, the control unit configured to drive the injection pump as a function of a particular value of the parameter characteristic of the flowrate in such a way that (i) the contrast agent follows a predetermined concentration pattern in the vascular system, (ii) the injection rate of the contrast agent is matched to instantaneous flow conditions in the vascular system, and (iii) a total amount of contrast agent injected is limited to a necessary minimum, the necessary minimum being defined by the predetermined concentration pattern, the predetermined concentration pattern further being specified to produce a constant contrast display of the vascular system while pictures are being taken of the object during a duration of the contrast agent injection.
2. A device as claimed in claim 1 , characterized in that the data processing device is designed to adjust the picture-taking rate, X-ray pulse duration, tube current and/or tube voltage of the X-ray unit.
3. A device as claimed in claim 1 , characterized in that the object is a heart.
4. A device as claimed in claim 1 , characterized in that the spontaneous movement characteristic parameter measuring device is an electrocardiograph apparatus.
5. A method of producing an image of an object that is subject to cyclic spontaneous movement and for controlling an injection rate of a contrast agent in a vascular system of the object, the method comprising:
a) producing a series of projected X-ray pictures of the object;
b) measuring a parameter characteristic of the spontaneous movement of the object;
c) controlling an X-ray exposure rate and/or a picture-taking rate as a function of a particular value of the spontaneous movement characteristic parameter in such a way that the X-ray exposure rate and/or the picture-taking rate is higher during a predetermined movement phase, to be displayed corresponding to a movement phase of greatest movement of the object than during the other movement phases of the object;
d) injecting the contrast agent at a controllable injection rate with an injection pump;
e) measuring a parameter characteristic of a flowrate in the vascular system; and
f) controlling the injection pump as a function of a particular value of the parameter characteristic of the flowrate in such a way that (i) the contrast agent follows a predetermined concentration pattern in the vascular system, (ii) the injection rate of the contrast agent is matched to instantaneous flow conditions in the vascular system, and (iii) a total amount of contrast agent injected is limited to a necessary minimum, the necessary minimum being defined by the predetermined concentration pattern, the predetermined concentration pattern further being specified to produce a constant contrast display of the vascular system while pictures are being taken of the object during a duration of the contrast agent injection.
6. The method of claim 5 , characterized in that controlling the X-ray exposure rate and/or picture-taking rate comprises adjusting the picture-taking rate, X-ray pulse duration, tube current and/or tube voltage of an X-ray unit configured to implement the method.
7. The method of claim 5 , characterized in that the object is a heart.
8. The method of claim 5 , characterized in that the spontaneous movement characteristic parameter is an electrocardiograph measurement.