JP2005287524A - Method and apparatus for determining functional parameter of radiographic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging processing method for a radiographic image and an improved processing apparatus. <P>SOLUTION: The apparatus uses a fluoroscopic radiographic equipment movable with respect to a table (4) placed between a source and a detector or a recorder on which a patient with a region of interest to be X-rayed is placed. The method comprises following steps: (a) a step for moving a support with respect to the table according to a given movement for a given time repeatedly; (b) a step for acquiring a series of two-dimensional images of the region of interest using the detector or the recorder during a movement of the support with respect to the table; (c) a step for reconstructing a series of three-dimensional models of the region of interest starting from the acquired images; and (d) a step for determining all functional parameters. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radiation image imaging process and an improvement of the processing apparatus. Specifically, embodiments and equivalents of the present invention are methods for monitoring the development of treatment operations performed in fluoroscopy imaging devices and angiographic operating rooms.

  Increasingly, blood vessels or angiographic operating rooms are used in therapeutic applications. Some of these require anatomical information about the vascular pathology to be confronted and handled, as well as further functional information, especially in the field of surgical neuroradiology. These applications include endovascular treatment for cerebrovascular disorders, carotid artery angioplasty, carotid and intracranial stent placement. Knowledge of functional information is necessary to make appropriate therapeutic decisions before performing a surgical procedure for all these applications, and to be able to evaluate the effectiveness of the treatment during the procedure in real time during the procedure. It is also very useful to be able to decide whether to stop or continue the treatment if necessary.

  Currently, the required functional information is obtained using magnetic resonance or tomography equipment, not using X-ray angiography or fluoroscopy equipment, but X-ray angiography equipment is used for the procedure itself. And cannot be done using magnetic resonance or computed tomography systems.

The processing means can be used to estimate a three-dimensional model of the region of interest of the subject, such as a patient, starting with a series of two-dimensional images collected in a known manner. In general, a single 3D model corresponding to a series of 2D images collected at the start of a procedure can all be used by a healthcare professional such as a surgeon during the procedure.
US Pat. No. 4,577,222 Ting-yim Lee, “Functional CT: physological models”, Trends in biotechnology, Vol. 20, no. 8 augmentation, 2002

  Therefore, it is impossible to monitor on the 3D model the operation of the instrument relating to the anatomy of the subject being treated (or the effect of the therapeutic operation being performed on the tissue being treated). Thus, medical personnel can only obtain anatomical information from this method. As a result, the subject is first examined by either magnetic resonance or tomography to collect all the functional information necessary to perform the examination and diagnosis. The subject is then taken to the vascular operating room for treatment itself. This surgical procedure scheme does not provide sufficient functional information that medical personnel need during the procedure. At present, this problem has been solved by state-of-the-art technology combining an X-ray system with, for example, a magnetic resonance system or a tomography system, which comprises a common subject operating table between the two systems. A vascular operating room will be combined with a magnetic resonance or computed tomography device. In the type in which such an X-ray system is combined with, for example, a magnetic resonance system, functional information is available in the magnetic resonance unit while a surgical operation is performed in the X-ray unit. However, such a system is very complex, very expensive and occupies a lot of space (equivalent to about two operating rooms). As a result, in practice these are limited to a few places.

  One embodiment of the present invention is a radiographic imaging method and apparatus such as fluoroscopy, for example, comprising means for supplying a radiation source such as an x-ray source and means for detecting imageable radiation, An apparatus is used that includes an apparatus that can be attached to a moving support that is movable relative to the analyte support means. The moving support is driven along a predetermined movement with respect to the object supporting means. A series of images of the subject area is processed and collected by means for detecting the movement of the support relative to the table to reconstruct a 3D model of the area. The moving support is driven to perform repetitive movements to form a regularly refreshed 3D model of the subject that is presented to the user.

  One embodiment of the present invention is a radiographic imaging apparatus, such as fluoroscopy, for example, comprising means for supplying a radiation source such as an X-ray source and means for detecting radiation capable of being imaged, which are It can be attached to a movable support that can move relative to the means for supporting the subject such as a table. Means are provided for driving or enabling the moving support in movement relative to the supporting means, such as a control device. Starting from a series of images in which the imaging area of the subject is collected by means for detecting radiation during a predetermined movement of the moving support relative to the support means, a 3D model of the area is reconstructed and shown to the user It comprises processing means or means enabling it. The control device is programmed to drive and control the movement of the moving support so that the moving support performs repetitive movement so that the processing means presents the user with a periodically refreshed 3D model. It has become.

  One embodiment of the present invention is a method for a radiographic apparatus, such as an X-ray apparatus, which provides a simple method for determining anatomical and functional information prior to surgery and particularly during surgery. is there. In one embodiment of the present invention, the method includes an X-ray source and a recording unit facing the source, and a subject having a region of interest irradiated with X-rays between the source and the recording unit. A series of using a fluoroscopic radiographic apparatus of the type in which a table to be mounted is arranged, the radiation source and the recording means are mounted on a movable support and movable relative to the table Determine functional parameters. The method includes: a) moving the support repeatedly for a predetermined time according to a predetermined movement relative to the table, b) collecting a series of images of the region of interest by the recording means during the movement of the support relative to the table, c) being collected Starting from a series of images and reconstructing a series of three-dimensional models of the region of interest, d) starting from a series of three-dimensional models and determining all functional parameters for the region of interest.

  One embodiment of the present invention is a fluoroscopic radiography apparatus, comprising an X-ray source and a recording unit facing the X-ray source, and having a region of interest to be imaged between the source and the recording unit. A table on which the subject is to be positioned is arranged, the source and the recording means are mounted on a moving support, and the control device can or is allowed to move the support according to the movement applied to the table Reconstructing a three-dimensional model of the region of interest starting from a series of two-dimensional images of the region of interest collected by the recording means during the movement applied to the table, The control device and the processing means can execute the method as described above.

  Other features and advantages of the present invention will become apparent from the following description of embodiments of the invention and variations thereof.

  Referring to FIG. 1, a fluoroscopic imaging apparatus comprises a radiation source supply means 1 (radiation tube and collimator) such as an X-ray source and a radiation detection means 2 (camera, sensor matrix or other device) such as a detector. And an image formed by irradiation is detected. The radiation source 1 and the detector 2 are arranged facing each other on each side of a support means 4 such as a table, on which a subject such as a patient having a region of interest to be imaged or X-rayed. A specimen will be placed. The radiation source 1 and the detector 2 are arranged on a moving support 3 such as a C-arm, and are rotatable about a rotation main axis that substantially coincides with the patient's body axis (double arrow 5 in FIG. 1). The total rotational movement around this axis is typically ± 120 degrees. In general, the C-arm 3 is also connected to be tiltable about a horizontal axis perpendicular to the patient axis (double arrow 6 in FIG. 1). This total rotational movement is typically ± 60 degrees.

  The control device 7 controls and provides the driving means for the C-arm 3 and rotates the C-arm around the patient's axis (and thus also the source 1 and the detector 2), in this way. A series of two-dimensional images corresponding to various observation directions around the patient axis are collected.

  This type of device has the advantage that 3D model images can be collected, reconstructed and displayed in real time. It is also possible to refresh the tomographic part of the anatomical region in real time. For example, by periodically refreshing the 3D model, a healthcare professional such as a surgeon monitors the progress of the vascular tool in real time during the surgery and has been or has been placed in the patient's bone. It is possible to monitor the propagation of cement, or to monitor the effectiveness of ablation tools such as radio frequency ablation.

  FIG. 2 illustrates a first embodiment of an apparatus that can use a method for determining a functional parameter set according to an embodiment of the invention described below. In the embodiment shown in FIG. 2, the collection device comprises generally the same means as the device shown in FIG. Unlike the embodiment shown in FIG. 1, the controller and patient 4 can move along a reciprocating back and forth movement while making a series of half rotations in more than 180 degrees alternately in one direction and the other. Is programmed to drive and control the C-arm around.

  Each half-rotation movement allows a complete series of two-dimensional images to be collected, thus allowing the device 8 to periodically reconstruct a new three-dimensional model. Thus, for a period of time during which the C-arm makes a series of half rotations around the patient and the table 4, the device 8 will reconstruct a series of three-dimensional models, one for each half rotation. The anatomical parameters are determined by displaying at least one of the three-dimensional models on the display means viewed by the surgeon, and are also prepared for diagnosis (if performed prior to surgery) or surgery if performed A series of functional parameters necessary for the evaluation of the progress of the process is determined.

  However, this alternative embodiment may require a series of acceleration and deceleration movements and is relatively relative to the collection device and the entire projection collected during the half rotation required to reconstruct the volume. High mechanical load may be applied.

  Another possible variant embodiment shown in FIG. 3 is that the radiation source 1 and the detector 2 follow a movement in which the axis between the source 1 and the detector 2 rotates while drawing the cone rotation continuously and repeatedly. Includes programming controller 7 to move. This type of collection movement is called “conical” (or circular tomography), rotation around the main axis corresponding to the double arrow 5 and back-and-forth movement around the other axis to which the arm 3 is connected (double Arrow 6) is combined. The processing means 8 generates a 3D model starting from a series of 2D images collected during rotation of the source 1 / detector 2 axis, as described in US Pat. No. 4,577,222. Programmed to reconfigure. This axis is driven continuously with uninterrupted conical rotation and the 3D model calculated by the processing means 8 is regularly refreshed (in the case of a 2D part of the image corresponding to the direction in which the surgeon works). Is the same).

  Accordingly, various three-dimensional models among the three-dimensional models collected and calculated in this way can be continued one after another without waiting time for a predetermined time. Furthermore, the acquisition of a two-dimensional image can be started, so that a three-dimensional modeling is possible at any time during the movement cycle of the source 1 / detector 2 assembly.

  Another possible variant embodiment is shown in FIG. In this embodiment, the C-arm 3 is driven according to a rotational movement (arrow 15) that repeats continuously around the main axis. This is done without a series of complete rotations (always in the same direction) around the table 4 and the patient. In order to allow this type of continuous rotational movement, power to the arm 3 (at the rotational joint of the remaining arm 3 of the support) uses wire elements that will limit the rotational distance of the arm. Supplied through commutator / brush type means 9 (or rotary contact) which is not necessary.

  The control device 7 and the processing means 8 are used for exchanging control data or collected data (especially a two-dimensional image collected by the detector 2) with the radiation source 1 and the detector 2, so A means 10 such as a link or a radio link is used. For example, this type of device allows a complete refresh of a three-dimensional model or partial image at a frequency on the order of 1 Hertz. Regarding the previous embodiment, in the series of three-dimensional models collected and calculated in this way, the three-dimensional models can pass one after another without waiting time in a time of about 1 second. It is possible to better define the functional parameters calculated from

  The processing device 8 means continuously stores a series of two-dimensional images on a sliding window corresponding to many two-dimensional images necessary for reconstruction of the three-dimensional model. The 3D reconstruction process is performed continuously in this sliding window, which allows continuous refreshing of the model at a rate that can be equal to the collection rate of individual projections. This is a means of obtaining a series of three-dimensional models for optimally determining the functional parameters to be determined during surgery. Only one rotation axis is required for this variant embodiment.

  Another possibility in one variant of this mode is to use a rotational movement around another rotational axis of the C-arm, for example in the plane passing through the focal point of the source and the center of the detector in the plane. It is to move with.

  The embodiment shown in FIG. 4 also enables power savings when acceleration / deceleration of the C-arm is avoided, specifically minimizing vibration and deformation of the mechanical structure, Ensures that the optimal reconstruction quality and consequently the function parameter determination is improved.

  Here, a method for controlling the apparatus as described above will be described first, and then a method for determining a series of function parameters will be described. Referring to FIG. 5, the method first determines, at a predetermined time, a series of three-dimensional models of the patient's region of interest placed on the table 4 of the apparatus described above. In a second step, functional parameters are calculated from this series of models in the form of a parameter map showing functional parameters such as perfusion values, blood flow, blood volume, average transit time or time to maximum, and permeability.

  The first step of determining a series of three-dimensional models at a predetermined time is performed by controlling the apparatus as described above. A 3D model is calculated starting from a series of 2D images. This three-dimensional model determination was made relatively frequently, starting with this type of collection and being reliably optimized to determine functional information. This optimization is usually on the order of one three-dimensional model per second. This frequency is determined by the rotational speed of the C-arm 3. For example, the apparatus used in FIG. 4 as described above requires one 180 degree rotation to collect a series of two-dimensional images necessary to reconstruct a three-dimensional model. That is, if the rotational speed of the C-arm 3 is x degrees per second, theoretically, one three-dimensional model is possible every 180 ° / x seconds. For example, if the rotation speed is 90 ° or 60 ° per second, a three-dimensional model can be generated every 2 seconds or 3 seconds, respectively.

  Furthermore, the total time required to collect a two-dimensional image is on the order of 45 seconds, which corresponds to the time required to “wash” the injected contrast bolus. The series of 3D models determined during the 45 seconds typically includes 15 to 45 3D models. As shown in FIG. 5, the instant at which the contrast agent was injected is shown on the time scale, from which the method controls the X-ray apparatus for a duration of 46 seconds from which the C-arm is moved 90 ° per second. And a three-dimensional model is determined every 2 seconds. The first three-dimensional model is collected within 2 seconds after the start of collection. A new 3D model n is determined every 2 seconds and so on until the 23rd of the last 3D model is collected. In general, it is not useful to collect any more images, firstly the injected bolus of contrast agent is already completely excluded from the region of interest considered, and secondly the patient This is because irradiating is not beneficial.

  In the case of continuous collection, as is possible with the apparatus according to FIG. 4, in a variant embodiment of the method, by using a sliding window of a series of two-dimensional images collected by the detection means 2, The collection frequency can be artificially increased. For example, the three-dimensional model n at time n can be determined by the rotation n of the C-arm 3. Similarly, rotation n + 1 can determine a three-dimensional model n + 1 corresponding to time n + 1, but an intermediate three-dimensional model corresponding to time n + 1/2 is a series of two-dimensional images of rotation n and a series of rotation n + 1. It can be calculated using a combination with the first half of the two-dimensional image.

  The collimation system can then be used to reduce the X-ray dose delivered to the patient and medical team. From a purely application point of view, it is usually not necessary to collect the cubic volume completely, and horizontal collimation strips can be used to reduce the collection to a relatively small number of axial sections or two-dimensional images.

  In the second step of the method, a series of three-dimensional models calculated so far are analyzed to determine a number of functional parameters. The theory underlying this step is that the gray value of a given voxel of a given three-dimensional model represents the material density at which X-rays are transmitted at the corresponding acquisition time at the corresponding point in space. When a bolus of contrast agent is injected into the vascular network of the human body or any tissue (via intravenous injection or intraarterial means), the amount of contrast agent, and consequently, proportional to the transient increase in gray value It shows that the blood volume in the corresponding area increases.

  In practice, the work performed by the operator to initiate the second step of the method is, for example, in one of the three-dimensional models determined so far, the region of interest in the input artery ( ROI). The method according to an embodiment of the invention thus defines an arterial blood input function (AIF). In each voxel of data collected and determined so far, the time strength of the signal is deconvolved using AIF, and the resulting residual function is called the impulse residual function (IRF). Starting from the fluctuation distribution of IRF over time, blood flow is defined as the height of the curve thus obtained (representing IRF), blood volume is defined in the area under the curve, and the average elapsed time is the curve Defined by the length of the first flat part of. If the blood barrier breaks within the tissue, the permeability is quantified by analysis of the IRF exponential decay.

  Many authors have developed algorithms for determining the values of various functional parameters based on the above description. For example, Ting-yim Lee's “Functional CT: physical models” Trends in biotechnology, Vol. 20, no. Reference to the Augmentation 8, 2002 paper gives more information on this type of algorithm.

  FIG. 6 also shows an example of an IRF curve, representing arteries (A), veins (V), and substantial increase (P).

  The use of the method and apparatus described above requires a much higher rotational speed than the scanner-type apparatus used in magnetic resonance and computed tomography, but it is a great advantage in that the observation area is very wide There is. The scanner only forms a section in that plane. Clinically, methods and devices according to embodiments of the invention as described above are applied to cerebrovascular disorders. By using the method and apparatus according to embodiments of the present invention, a means is provided to expedite diagnosis and treatment procedures for this type of disorder. The operation time frame from the time of occurrence of cerebrovascular disorder to the time of irreversible results is about 2 to 3 hours. For the treatment given to this case, a thrombolytic agent and a catheter with a clamp inserted into the site closest to the cerebrovascular disorder position are used. For the diagnosis, the above method and apparatus are used. Provides a pre-operative means of classifying or marking the location of cerebrovascular disorders, and without the need to move the patient between a conventional fluoroscopic x-ray system and a magnetic resonance or tomographic scanner system In this way, the disability treatment can be observed as closely as possible before surgery.

  Advantageously, but optionally, the method has at least one of the following features: the support is driven along a series of half rotations that rotate alternately in one direction and the other around the table. The support is driven to apply a repetitive conical rotational movement about an axis passing through the focal point of the source and the center of the recording means; the support is driven according to a continuous repetitive rotational movement around the table A series of two-dimensional images are continuously stored or stored in the image storage means on the sliding window, corresponding to the many images required for reconstruction of the three-dimensional model, and the processing is performed in this sliding -Applies to continuous reconstruction of 3D models on windows. During the method, the following sub-steps are included: selecting a region of interest in one vessel of the three-dimensional model; determining an arterial blood input function in the selected region of interest; on each voxel common to a series of three-dimensional models Using an arterial blood input function, deconvolve a signal with an intensity that varies with time; determine a residual impulse function and calculate functional parameters.

  Advantageously, but optionally, the device has at least one of the following characteristics: the controller drives along a series of half rotations that rotate alternately in one direction and the other around the table The controller is programmed to apply the repetitive conical rotational movement to an axis passing through the focal point of the source and the center of the recording means; the controller is programmed to operate the table Programmed to drive the support along successive repetitive rotational movements around the support; the support comprises a power supply with commutator / brush-type means; the apparatus is a controller and / or processing means Comprises optical connection means for exchanging data with the radiation source and / or recording means; the apparatus comprises a radio link forming means for the control device and / or processing means to exchange data with the radiation source and / or recording means Be equipped The controller and / or processing means exchange data with the source and / or recording means and the brush / commutator means; the processing means is necessary for reconstructing the three-dimensional model on the sliding window Means for continuously storing or storing a series of two-dimensional images corresponding to many images, and means for continuously executing reconstruction of the three-dimensional model on the sliding window.

  Various changes in configuration and / or function and / or steps, or equivalents in function and / or method and / or result, are disclosed by those skilled in the art without departing from the scope and limitations of the invention. Or it is implemented and proposed for its equivalent.

1 is a diagram of an apparatus that collects X-ray fluoroscopy images. FIG. FIG. 4 is a diagram of possible collection movements in an apparatus according to an embodiment of the invention. FIG. 4 is a diagram of possible collection movements in an apparatus according to an embodiment of the invention. FIG. 4 is a diagram of possible collection movements in an apparatus according to an embodiment of the invention. FIG. 5 is a functional diagram of a method according to an embodiment of the invention that can be used in the apparatus of FIGS. The figure of the derivation | curving curve for drawing the functional information by embodiment of this invention.

Claims (21)

In a radiographic imaging method using an apparatus comprising a radiation source supply means (1) and a radiation detection means (2) attached to a movable support (3) movable relative to a subject support means (4) There,
Driving the movable support (3) along a predetermined movement relative to the subject support means (4);
A series of images of the subject area collected by the detection means (2) during the movement of the moving support (3) relative to the subject support means (4) is processed to produce a 3D model of the area Reconfigure and
Driving the moving support (3) so that the movement is performed repeatedly to form a periodically refreshed 3D model of the subject;
A radiographic imaging method comprising:   The said moving support body (3) is driven along a series of half rotations which rotate in one direction and another direction around the said object support means (4) alternately. the method of.   2. The moving support (3) is driven to apply a repetitive conical rotational movement with respect to an axis passing through the focal point of the source (1) and the center of the detection means. The method described.   Method according to claim 1, characterized in that the moving support (3) is driven according to successive repeated rotational movements around the subject support means (4).   A series of 2D images are continuously stored or stored corresponding to the many images needed to reconstruct the 3D model on the sliding window, and processing is performed on the sliding window to reconstruct the 3D model continuously. 5. The method according to claim 1, wherein the method is applied to a configuration. Means (1) for supplying a radiation source;
Means (2) for detecting the radiation arranged together with the radiation supply means on a movable support (3) movable relative to the subject support means (4) on which the subject can be placed;
Control means (7) capable of driving the movable support (3) in movement relative to the subject support means (4);
Starting from a series of images in which the imaging area of the subject was collected by the detection means (2) during a predetermined movement of the moving support (3) relative to the subject support means (4), Processing means (8) capable of reconstructing and showing the 3D model;
With
The control means (7) is programmed to control the movement of the moving support (3) so that the moving support moves repeatedly, and the processing means (8) is periodically refreshed. A radiographic imaging apparatus, characterized by forming a 3D model.   The control means (7) is programmed to drive the moving support (3) along a series of half rotations that rotate alternately in one direction and the other around the subject support means (4). The apparatus according to claim 6.   The control means (7) is programmed to drive the moving support (3) to apply repetitive conical rotational movement about an axis passing through the focal point of the source (1) and the center of the detection means. The apparatus according to claim 6.   The control means (7) is programmed to drive the moving support (3) along a continuous repetitive rotational movement around the subject support means (4). The device described.   Device according to claim 9, characterized in that the mobile support (3) comprises a power supply with commutator / brush type means (9).   10. The apparatus according to claim 9, wherein the control means and / or the processing means comprise optical connection means (10) for exchanging data with the source (1) and / or detection means (2). The apparatus according to any one of 10.   The apparatus according to claim 1, characterized in that the control means and / or the processing means comprise radio link forming means (10) for exchanging data with the source (1) and / or detection means (2). The apparatus according to any one of 9 and 10.   11. The control means and / or the processing means exchange data through brush / commutator means with the source (1) and / or detection means (2). The device described. The processing means is
Means for sequentially storing or storing a series of 2D images corresponding to a number of images required for reconstruction of the 3D model on a sliding window;
Means for continuously executing 3D model reconstruction means on the sliding window;
The apparatus according to claim 9, comprising: A radiation source supply means (1) and a recording means (2) facing the radiation source (1) are provided, and an object having a region of interest to be imaged is placed between the radiation source and the recording means. A subject support means (4) to be operated is arranged, and the radiation source and the recording means are mounted on a movable support (3) movable relative to the subject support means (4). A method of determining a series of functional parameters using a type of radiography apparatus, the method comprising:
a) moving the support (3) repeatedly for a predetermined time according to a predetermined movement relative to the support means (4);
b) collecting a series of images of the region of interest by the recording means during movement of the moving support (3) relative to the support means (4);
c) reconstructing a series of 3D models of the region of interest starting from a series of collected images;
d) starting from the series of 3D models, determining all functional parameters for the region of interest;
A method involving that. Said step d) selects d1) a region of interest in one blood vessel of said three-dimensional model;
d2) determining an arterial blood input function in the selected region of interest;
d3) On each voxel common to a series of three-dimensional models, use an arterial blood input function to deconvolve a signal with intensity that varies over time;
d4) determine the residual impulse function and calculate the functional parameters;
The method of claim 15 comprising:   17. The moving support (3) is driven along a series of half rotations that rotate alternately in one direction and the other around the subject support means (4). The method described in 1.   16. The moving support (3) is driven to apply a repetitive conical rotational movement with respect to an axis passing through the focal point of the source (1) and the center of the detection means. 16. The method according to 16.   17. A method according to claim 15 or 16, characterized in that the moving support (3) is driven according to successive repetitive rotational movements around the subject support means (4).   A series of 2D images are continuously stored or stored corresponding to the many images needed to reconstruct the 3D model on the sliding window, and processing is performed on the sliding window to reconstruct the 3D model continuously. 17. A method according to claim 15 or 16, wherein the method is applied to a configuration. Radiation source supply means (1);
Recording means (2) facing the radiation source (1);
A radiography apparatus comprising:
A subject support means (4) on which a subject having a region of interest to be imaged is positioned is disposed between the radiation source and the recording means, and the radiation source and the recording means are connected to the subject. Mounted on a movable support (3) movable relative to the specimen support means (4);
The radiation imaging apparatus is
Control means (7) including means capable of moving the movable support (3) according to the movement applied to the support means (4);
Processing means (8);
Is configured to have
21. A radiation imaging apparatus, wherein the control unit and the processing unit are capable of executing the method according to any one of claims 15 to 20.

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