Patent Application
20130077756
This application claims priority of German application No. 10 2011 083 408.7 filed Sep. 26, 2011, which is incorporated by reference herein in its entirety.
The application relates to an imaging method and apparatus for displaying at least one target object, such as one or a plurality of blood vessels and/or an organ in an area of a patient under examination, such as during a medical intervention.
Two- and three-dimensional digital subtraction-rotational angiography (2D or 3D DSA rotational angiography) is a standard method used for assessing the vascular anatomy before and during medical interventions. In the case of digital subtraction angiography (DSA), after the generation of mask images, images without contrast medium, and filler images, images with contrast medium, these are subtracted from one another so that only the time-related changes caused by the contrast medium, which represent the vessels, are obtained.
A C-arm X-ray system for digital subtraction angiography of the type illustrated by way of an example in
By rotating it about a center of rotation between the X-ray emitter 3 and the X-ray detector 4, for example, the C-arm 2 can be adjusted to any spatial position by an articulated-arm robot 1, such asably having six axes of rotation and six degrees of freedom. The articulated-arm robot 1 has a basic frame which, for example, is mounted on the floor in a stationary manner and to which is attached a carousel that is rotatable about a first axis of rotation. A robot rocker beam is swivel-mounted on the carousel about a second axis of rotation and to which a robot arm is attached in a rotatable manner about a third axis of rotation. A robot hand is mounted at the end of the robot arm in a rotatable manner about a fourth axis of rotation. The robot hand has a mounting element for the C-arm 2, which can swivel about a fifth axis of rotation and can be rotated about a sixth axis of rotation that is perpendicular to said fifth axis of rotation.
Realization of the X-ray diagnostic apparatus does not rely on the industrial robot. Conventional C-arm devices can also be employed.
The X-ray image detector 4 can be a rectangular or square, flat semiconductor detector which is developed from amorphous silicon (a-Si). However, integrating and possibly metering CMOS detectors can also be used.
A patient table 5 for recording the heart of a patient 6 as the subject of examination, for example, is located in the beam of the X-ray emitter 3. A system control unit 7 with a display system 8, which receives and processes the video signals of the X-ray image detector 4 (operator control elements, for example, are not shown), is connected to the X-ray diagnostic apparatus. The X-ray images can then be viewed on a monitor 9. In one embodiment, a suspended monitor arrangement 13 with a first display 14 and at least one further display 15 can be attached to the ceiling.
Two C-arms are being increasingly used in radiology. These are so-called biplane systems.
In X-ray diagnostics, a screened organ or blood vessel is represented in two dimensions. A 3D representation is possible by rotating the C-arm about the organ or vessel, with simultaneous sequential recording. As a result, dependent upon image frequency and rotational speed, several hundred two-dimensional X-ray images are created, which can then be converted into 3D images.
It is possible with the aid of ultra wideband (UWB) radar to compute the third dimension—even with an individual X-ray image. As a result, the patient is exposed to a much lower X-ray dosage.
Other features of combining X-ray apparatus with UWB radar:
As already mentioned in the introduction, 3D X-ray images are generated by rotating the X-ray apparatus around the patient. By doing this, X-ray images are generated in each angle of rotation and converted into 3D in a computer, for example the said display system 8.
A patient examination is realized by connecting the patient to an ECG unit, for example. Initiation of the X-ray radiation normally occurs after a time delay; the doctor injects the contrast medium and from his experience knows approximately how rapidly the contrast medium spreads. He then activates the X-ray radiation. A series of X-ray images is then initiated by the left ventricle of the heart, for example; the two heart phases of interest are selected and the pumping volume is calculated.
The application is based on the problem of improving the representation of the target object in the area under examination, for example vessels, in accordance with the method or the medical apparatus mentioned in the introduction.
The object of the application is achieved by the subject matter of the independent claims. Developments of the application are revealed in the features of the dependent claims.
Due to the disclosed combination of the UWB radar and the X-ray installation it is possible to determine the movements of the heart and the coronary vessels in the depth of the body in a contact-free manner and to combine the radar image with an X-ray image, which results in a 3D image that has been generated at a low dosage. The 3D image is reproduced on an indicating device, for example a display or monitor.
Compared to the prior art, the combination of UWB radar and X-ray angiography provides an improved, up-to-date display of the blood vessels in the area under examination and exposes the patient to a lower level of radiation.
Patient monitoring is likewise possible in a contact-free manner. No patient monitors (for example ECG) are necessary in the treatment room. This results in an extended anti-collision system around the patient. The triggering of the X-ray apparatus can be controlled by the flow of contrast medium in the patient. The pumping volume of the heart can be measured and calculated without radiation.
Embodiments of the application with developments according to the features of the dependent claims are explained in more detail with the aid of the following drawing, without being restricted to them.
According to the application, the procedure is as follows:
UWB is a radio modulation technique based on the transmission and reception of pulses of very short duration (often less than one nano second (<10−9 s) with a very wide bandwidth. The signals reflected from different depths of the body are detected with a receiving antenna or receiving sensor. Due to the heart beat and the resulting movements of the coronary blood vessels, the boundary layers of the organ are displaced and deformed, thus influencing the measured signal. Measurement data can be obtained from these anatomical movements and the movement of the organ and the coronary movement can be reconstructed with respect to location and time.
If the patient is irradiated with low-power (<1 mW) wideband electromagnetic pulses from different directions, then these penetrate to different depths of the body and are partially reflected at successive boundary layers of the various types of tissue.
Since the various types of human tissue have typical absorption and reflection characteristics, organ movements such as heartbeat and the movements of the coronary vessels can be precisely detected by ultra wideband radar systems.
Signals (see RTC UWB preprocessing 27) which are analogous to the movement of the heart/of the coronary vessels and enable a 3D reconstruction of the moving heart, are generated from the receivers of the UWB radar system in an electronic evaluator with a computer. This 3D data set can now be fed to the image computer 8 of the X-ray system and combined with the X-ray image, for example as in the Siemens AG “Axiom Ards” X-ray system and the “AXIS” image computer 8.
The associated radar image (radar images are three-dimensional) is assigned in the image computer to each X-ray or fluoroscopic image (these are two-dimensional). A new 3D image that combines the features of the X-ray image (higher resolution) with the features of the UWB radar system (3D representation without radiation burden) is produced by combining the X-ray image with the UWB radar image.
Vital patient functions, such as breathing or heart rhythm, can be monitored with the aid of the UWB radar in a contact-free manner. Possible patient panic states can also be immediately detected and appropriate measures initiated.
Furthermore, it is possible with the aid of the UWB radar to prevent unintentional contact with sterile devices in the examination room and possibly to trigger an alarm.
The movements of the patient table and the X-ray apparatus can also be monitored with the system. Movement can be stopped and/or an alarm triggered as soon as a patient, an operator or a device is located in the collision zone.
As the various types of human tissue have typical absorption and reflection characteristics, blood vessels can be accurately detected and displayed by the four ultra wideband radar systems. The flow of blood or contrast medium in the vessels can be measured by the so-called Doppler effect. Consequently, it is possible to trigger the X-ray radiation only when the contrast medium has reached the appropriate position in the vessel.
The pumping volume of the left ventricle of the heart can be determined. (EF=ejection fraction).
The heart phases of interest are the end diastole (ED) and the end systole (ES). The volumes in the respective heart phase can be determined and the ejection fraction (EF) calculated with the UWB radar system.
The ejection fraction corresponds to the ratio in percentage of EDV and ESV to EDV and is expressed mathematically as:
100% ×(EDV−ESV)/ESV,
where EDV (ml) is the volume of the ventricle in the ED phase and ESV (ml) is the volume of the ventricle in the ES phase.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102011083408.7 | Sep 2011 | DE | national |
