CN100473355C - System for introducing a medical instrument into a patient - Google Patents

Abstract

The invention relates to a medical system comprising a medical instrument to be introduced into a patient; means for acquiring a two-dimensional X-ray image of the medical instrument; means for acquiring a three-dimensional ultrasound data set of the medical instrument by using an ultrasound probe; means for positioning the ultrasound probe within a reference range of the X-ray acquisition device; means for selecting a region of interest around said medical instrument within the three-dimensional ultrasound data set, which specifies a first position of said region of interest within a reference range of the ultrasound acquisition means; for transforming the first position into a second position within said reference range of the X-ray acquisition device; and means for generating a bimodal representation of the medical instrument detection by combining the two-dimensional X-ray image and three-dimensional ultrasound data comprised in the region of interest.

Description

System for introducing a medical device into a patient

field of invention

The invention relates to a medical system comprising a medical instrument to be introduced into a patient and means for making said medical instrument visible. The invention also relates to the method used in said system. The invention finds its application, for example, for introducing a catheter into a patient's heart during electrophysiological interventional procedures.

Background of the invention

Clinical applications in which medical instruments must be introduced into patients are becoming very common. Notably, growing interest in minimally invasive methods for treating heart disease has compelled the development of methods and devices that allow physicians to introduce medical instruments to predetermined locations inside or outside the heart. In electrophysiology, for example, catheters must be guided to specific locations on the walls of ventricles or arteries in order to measure electrical impulses or to ablate wall tissue.

US Patent 6,587,709 discloses a system for introducing a medical instrument into a patient. Such systems acquire real-time 3D image datasets by using ultrasound probes. An advantage of acquiring a real-time 3D image data set is that depth information is obtained. The advantage of using the real-time 3D ultrasound image mode is that the surrounding anatomy is visible, which makes it easy for the doctor to guide the medical instrumentation. The system also includes positioning means for positioning the medical instrument within the 3D ultrasound data set, which positions the three ultrasound receivers mounted on the medical instrument relative to said ultrasound probe, such positioning allowing automatic selection of the plane to be imaged , which includes at least one portion of a medical device. Therefore, it is not necessary to readjust the ultrasound probe position.

A first disadvantage of such a 3D ultrasound data set is that it has a narrow field of view which does not cover the entire part of the patient's body involved in the introduction and placement of the catheter. So in order to introduce the catheter throughout the procedure, the ultrasound probe must be moved several times. At each displacement, a preoperative step of positioning the ultrasound probe in the reference range of the interventional space is required, since the position of the catheter is measured relative to the position of the ultrasound probe. Such pre-procedural steps can delay and complicate the interventional procedure.

A second disadvantage of the ultrasound imaging modality is that it has low resolution. Therefore, the acquired 3D data set does not give an acceptable quality image of the catheter and its surrounding objects.

A third disadvantage of the ultrasound imaging modality is that the patient's body has certain areas where the thoracic skeleton blocks the ultrasound scan, and no usable image can be output.

Contents of the invention

It is therefore an object of the present invention to provide a medical system for introducing a medical instrument into a patient which gives improved visibility of the medical instrument and its surrounding anatomy throughout the operation.

This is achieved through a medical system that includes:

- medical devices to be introduced into a patient;

- an X-ray acquisition device for acquiring a two-dimensional X-ray image of the medical instrument;

-ultrasound collection device, for using the ultrasound probe to collect the three-dimensional ultrasound data set of the medical instrument;

- a positioning device for providing a position of the ultrasound probe within the reference range of the X-ray acquisition device;

- selection means for selecting a region of interest around said medical instrument in a 3D ultrasound data set, which specifies a first position of said region of interest within a reference range of said ultrasound acquisition device;

- conversion means for transforming the first position of the region of interest within the reference range of the ultrasound acquisition device into the first position of the region of interest within the reference range of the X-ray acquisition device by using the position of the ultrasound probe a second location of the region of interest;

- Generating means for generating and displaying a bimodal representation of said medical instrument, wherein said two-dimensional X-ray image and three-dimensional ultrasound data comprised in said region of interest are combined using said second position.

By means of the present invention, a bimodal representation is provided in which two-dimensional (2D) X-ray data and three-dimensional (3D) ultrasound data are combined. Two-dimensional X-ray data provides good visibility and high resolution of medical instruments and bone structures. 2D X-ray data also benefit from a large field of view, which allows visualization of the entire region of the patient's body that is of interest for electrophysiological procedures.

3D ultrasound data provides good visibility of soft tissue and sometimes blood vessels around the medical instrument. In addition, 3D ultrasound data give an indication of depth, which 2D X-ray images cannot provide because the X-ray images only provide projections of the medical instrument in terms of the geometry of the X-ray acquisition device. Such a geometric relationship defines the line of projection along which the absorption of x-rays by the exposed tissue of the patient accumulates. Therefore, the visibility of the surrounding parts of the medical instrument is improved by the combination of 2D X-ray and 3D ultrasound data.

To provide such a combination, the system first positions the ultrasound probe and the 3D ultrasound data set within the reference range of the x-ray acquisition device. Such a reference range of the X-ray acquisition device is assumed to be fixed. Therefore, assuming no movement of the ultrasound probe, the position of any point of the 3D ultrasound data set within the reference range of the x-ray acquisition device can be derived. Since the position of the 2D X-ray image on the X-ray detector within the reference range of the X-ray acquisition device is given by the geometric relationship of the X-ray acquisition device, the positioning of the 3D ultrasound data set within the reference range of the X-ray acquisition device allows the use of The 2D X-ray image is used to map the 3D ultrasound data set, that is, the point of the 2D X-ray image is used to map the projection of any point of the 3D ultrasound data set according to the geometric relationship of the X-ray acquisition device.

The system according to the invention also selects a region of interest in the 3D ultrasound data set around the medical instrument and provides a first position of said region of interest within the reference range of the ultrasound acquisition device. The goal of such selection, made manually or automatically, is to suppress any ultrasound data that blocks the visibility of the medical instrument.

The first position represented by the coordinates of the reference range of the 3D ultrasound acquisition device is then transformed into a second position of the medical instrument within the reference range of the X-ray acquisition device by using the positioning of the ultrasound probe.

The system according to the invention finally generates a bimodal representation in which the 3D ultrasound data comprised in said region of interest are combined to 2D X-rays using said second position of the region of interest within the reference range of the X-ray acquisition device. data.

Preferably, a bimodal representation is generated from the 2D X-ray image. On this 2D x-ray image, all x-ray intensity values of points with corresponding points in the selected region of interest of the 3D ultrasound data set are combined with ultrasound intensity values.

The means for selecting a region of interest predefines a reference plane in which a part of the medical instrument is included. In a first embodiment of the invention, the region of interest is comprised in said reference plane, which for example comprises the tip of the medical instrument in contact with the wall tissue and perpendicular to the orientation of the X-ray acquisition means. Therefore, the means for generating the bimodal representation are intended to combine the 2D X-ray image with the 2D ultrasound image obtained by sampling the 3D ultrasound data set on reference plane coordinates within the reference range of the X-ray acquisition device. A first advantage of the first embodiment of the invention is that it is very simple. A second advantage is that any ultrasound data blocking the medical instrument and its surroundings is removed.

In an alternative, the selecting means comprises detecting means for detecting the medical instrument in the region of interest of the 3D ultrasound data set. Such detection is obtained automatically, for example, by using image processing techniques, such as filters for enhancing and thresholding elongated shapes. In the bimodal representation, the x-ray intensities of points belonging to the 2D x-ray image of the detected medical instrument are advantageously kept constant. A first advantage is that the dual mode representation benefits from the high resolution of the medical instrument provided by the X-ray acquisition device.

A second advantage of this detection is that it is based on image processing techniques and does not require any specific medical instruments, such as those equipped with active localizers. Another advantage of the system according to the invention is that it allows non-negligible cost savings, taking into account that the medical equipment must be changed for each new patient.

A third advantage of this detection is that it gives the position of the tip of the medical instrument. This location, combined with the bimodal representation, can facilitate the generation of an electrically driven map of the heart wall. In fact, in such procedures, the medical instrument is a catheter whose end is equipped with a sensor for measuring the electrical impulses in the heart wall. When the catheter touches the heart wall, the user actuates the sensor. Measurements of electrical pulses are made at the current position of the catheter. The position of the catheter provided by the system according to the invention provides the position of the point on the electrical drive map corresponding to said current position and said electrical measurement. By making the bimodal representation visible, it is possible for the user to estimate the distance between the current measurement point and the previous measurement point. Therefore, the system according to the invention facilitates a fast, uniform and complete mapping of the heart wall.

In a second embodiment of the invention, the system according to the invention also includes a region for segmenting the wall tissue in the 3D ultrasound data set. Therefore, in the 2D x-ray image only the x-ray intensity values of points belonging to the wall tissue region are combined with the corresponding ultrasound intensity values. Therefore, bimodal means more than X-ray intensity values inside the heart wall and ultrasound intensity values inside and outside the heart wall. One advantage is that bimodal representations benefit locally from the best information available.

In a third embodiment of the invention, the region of interest is a 3D subset of the 3D ultrasound data set which is either located behind the reference plane in the X-ray direction or forms a slice around the reference plane. A volume rendering of 3D ultrasound data comprised in the selected region of interest is provided. By combining the intensity values of the points of the 2D x-ray projection with the intensity values of the corresponding points on the volume rendering map, a bimodal representation is constructed. One advantage is to provide a three-dimensional view of the surrounding tissue.

The system according to the invention is capable of acquiring 2D X-ray images and 3D ultrasound data sets in real time. Therefore, medical instruments can be tracked in each 2D X-ray image and 3D ultrasound data set.

In a fourth embodiment of the invention, the system comprises control means for periodically triggering the probe positioning means. In fact, the position of the ultrasound probe within the reference range of the X-ray acquisition device can be changed by the patient's external movement, such as breathing movement during clinical operations. Therefore, the position of the ultrasound probe must be regularly updated.

means of motion of the current 3D ultrasound data set relative to the previous 3D ultrasound data set acquired at time t-1. One advantage is that small displacements of the ultrasound probe can be corrected without triggering the probe positioning device, and therefore without interrupting real-time visibility of the medical instrument.

These and other aspects of the invention are illustrated and understood with reference to the embodiments described hereinafter.

Brief description of the drawings

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a system according to the invention,

2 is a schematic diagram of a device for locating the position of an ultrasound probe within an X-ray reference range when the ultrasound probe is equipped with an active locator,

Figures 3, 4a, 4b are schematic illustrations of a device for locating the position of an ultrasound probe within an X-ray reference range when the probe is equipped with a belt comprising radio-opaque markers,

5 is a schematic diagram of a device according to the invention for positioning a medical instrument and determining a surface of said medical instrument in a 3D ultrasound data set,

Fig. 6 is a schematic diagram of a device for transforming a first position of the region of interest within the reference range of the ultrasound acquisition device into a second position of the region of interest within the reference range of the X-ray acquisition device,

Fig. 7 is a schematic diagram for generating a bimodal representation according to the first embodiment of the present invention,

Fig. 8 is a schematic diagram for generating a bimodal representation according to a second embodiment of the present invention,

Fig. 9 is a schematic diagram for generating a bimodal representation according to a third embodiment of the present invention,

10 is a schematic diagram of an apparatus for compensating for motion between a current 3D ultrasound data set acquired at a current time and a previous 3D ultrasound data set acquired at a previous time,

Figure 11 is a functional diagram according to the method of the present invention.

Detailed Description of the Invention

The present invention relates to a system for introducing a medical instrument into a patient. Such a system is particularly adapted for introducing a catheter into the heart for the purpose of diagnosing and treating heart disease, but it can be used more generally for introducing any other medical instrument- - eg a needle - is introduced into the patient.

The schematic diagram of Fig. 1 shows a patient 1 arranged on a patient table 2, whose symbolically represented heart 3 is being treated by means of a catheter introduced into the body. The system comprises a device 5 for acquiring a 2D X-ray image of a patient's body. The X-ray acquisition device comprises a focused X-ray source 6 and a detector 7 . Advantageously, these X-ray acquisition devices 5 are C-arm systems, as is usually the case in a Cathlab room. The advantage of such a C-arm system is that it is possible to rotate around the patient's body in order to produce multiple orientations of the patient at known orientation angles. 2D X-ray images.

The system according to the invention also comprises means 8 for acquiring a 3D ultrasound data set from an ultrasound probe 9 which is placed on the patient's body and fixed with a fixation device, such as a strap 10 or a stereotactic arm. It should be noted that the 2D X-ray images and 3D ultrasound data sets are acquired in real time, which enables real-time visibility of the medical instrument as it is introduced into the patient.

The X-ray acquisition device 5 is associated with a reference range of coordinates (O, x, y, z) - referred to here as the X-ray reference range - in which the geometric relationship of the focused X-ray source 6 and the detector 7 is known of. It should be noted that the X-ray reference range (O, x, y, z) is limited to the fixed part of the X-ray acquisition device and not limited to the C-arm. Therefore, the orientation of the C-arm can be represented in the X-ray reference range. However, the geometry of the X-ray acquisition device depends on the specific position of the C-arm.

The system according to the invention also comprises means 11 for positioning the position of the ultrasound probe 9 within the X-ray reference range (0, x, y, z) for selecting a region of interest around the medical instrument in the 3D ultrasound data set And be used for providing the device 12 of the first position Loc1 of the region of interest in the reference range (O ', x', y', z') of the ultrasonic acquisition device, for the reference range of the ultrasonic acquisition device (O ', x', y', z') the first position Loc ₁ of the region of interest is converted into the second position Loc ₂ of the region of interest in the X-ray reference range (0, x, y, z) means 13 , and means for generating a bimodal representation BI by combining data from the 2D X-ray image with 3D ultrasound data included in the region of interest and located by the second location Loc ₂ . The bimodal representation BI is displayed on the screen 15 .

Referring to FIG. 2 , the probe positioning device 11 is based in a first method on an active positioner 16 arranged on the ultrasound probe 9 , well known to those skilled in the art. Said active positioner 16, eg an RF coil, is intended to transmit RF signals to an RF receiving unit 17 placed under the patient's body and incorporated eg in a watch. The RF receiving unit sends received signals to the measuring device 18 for measuring the position of the ultrasonic probe 9 within a known reference range, such as the reference range (O, x, y, z) of the X-ray acquisition device 5 . It should be noted that the active positioner 16 must be two-dimensional and placed on the ultrasound probe 9 in such a way that accurate measurements of the position and orientation of the ultrasound probe can be calculated. It should be noted that guidance based light positioners can also be used. A first advantage of this first method is that it provides a precise position of the ultrasound probe. A second advantage is that it is performed in real-time, so can be triggered during clinical procedures.

In the second method of the probe positioning device 11 shown in FIG. 3 , the ultrasound probe is mounted on a belt 10 equipped with at least three non-aligned interrelated radio-frequency opaque markers M ₁ , M ₂ , and M ₃ . Secured around the patient's body. For example the belt 10 comprises a plexiglass plate in which are fixed three non-aligned interrelated radio-opaque markers.

The three marks M ₁ , M ₂ , and M ₃ belong to the same plane, so at least one 2D X-ray projection 2DXR ₁ collected with the orientation angle θ ₁ of the C-arm system 5 is required to determine the ultrasonic probe in the X-ray reference range (O , the position within x, y, z). However, since the three markers are interrelated and non-aligned, meaning that they form a solid quadruplet, it is well known to those skilled in the art that the position of the probe is fully dictated by the X-ray projection 2DXR ₁ .

Referring to Figure 4a, we consider the detector reference range (dO, dx, dy). For example, as in the first 2D X _{- ray} image 2DXR ₁ the coordinates ₍ dx ₁ , dy _{1 )} , _{( dx 2} , dy ₂ ), six parameters like (dx ₃ , dy ₃ ) completely define the position of the ultrasound probe 9 in the X-ray reference range (O, x, y, z). A first advantage of using radio-opaque markers M ₁ , M ₂ , M ₃ is that they appear in the 2D X-ray projection with very high contrast, which facilitates their positioning. Such positioning can be obtained manually or automatically. In the manual case, the user may click on at least two radio-opaque markers in each 2D X-ray image. In the automatic case, image processing techniques known to those skilled in the art, such as morphological filters, for example, can be used to detect radio-opaque markers that appear as high-contrast spots in 2D X-ray projections. A second advantage is that such localization is performed in real-time, so that no near-interventional steps are implied. It should be noted, however, that the ultrasound probe does not need to be displaced beforehand during the clinical procedure since it is intended to be used once the medical instrument has been introduced into the cavity to be explored in the patient. A third advantage is that it introduces no metallic objects in the field of view of the X-ray and ultrasound acquisition devices.

In an alternative to the second method, a second 2D X-ray image 2DXR ₂ is acquired at a second orientation angle θ ₂ of the C-arm system 5 as shown in Fig. 4b. This second X-ray image allows to determine the coordinates ( _dx'1 , _dy'1 ) of a _{new set of projections P'1, P'2 , P'3 of} the three markers _M1 , M2 and _M3 ( dx' ₂ , dy' ₂ ), (dx' ₃ , dy' ₃ ). It should be noted that positioning the points P ₁ , P ₂ , P ₃ and P' ₁ , P' ₂ , P' ₃ obeys the appearance constraints: e.g. this means that the line L ₁ linking the source focus point to P ₁ as including P The projection line L' ₁ of ' ₁ on the second X-ray image 2DXR ₂ appears. A first advantage is that _P'1 does not have to be searched within the entire image, but only on the projection line L' ₁ . A second advantage is that it gives a way of associating the points _P1 , _P2 , _P3 and _P'1 , _P'2 , _P'3 with the correct markers _M1 , _M2 and _M3 .

Such positioning of the ultrasound probe 9 involving two 2D X-ray images is not performed in real-time and must therefore be performed in a proximal-interventional step of the clinical procedure. The advantage of acquiring two 2D X-ray images is that the accuracy of positioning is greatly improved.

Once the ultrasound probe 9 is placed within the X-ray reference range (O, x, y, z), the orientation of the probe is known, so the position of the 3D ultrasound data set 22, also called the 3D ultrasound cone, can be obtained. This is obtained by the transformation device 13, which calculates the position of a point of the 3D ultrasound data set in the X-ray reference range from the position of the ultrasound probe. It can also be obtained according to the geometric relationship of the X-ray acquisition device. Projection on the detector.

Referring to FIG. 5 , the system according to the invention comprises means 12 for selecting a region of interest 35 around a medical instrument 4 within a 3D ultrasound data set 21 . A reference plane that includes a part of a medical instrument is specified. Advantageously, said reference plane is chosen perpendicular to the direction of orientation of the X-ray acquisition device. The region of interest is obtained by clipping a subset of 3D ultrasound data behind said reference plane or by clipping a slice formed around said reference plane. In this way, structures in the 3D ultrasound data set that would block the visibility of the medical instrument are removed. In a first method, the user interactively selects a region of interest 35 in the 3D ultrasound data set. In a second method, the position of the reference surface can be predetermined, for example, at a predetermined reference depth equal to one third of the depth of the 3D data record. This predetermined reference plane may also be rotated for searching views within the 3D ultrasound data set from which the medical instrument is more visible. A reference plane 33 of rotation is obtained. Advantageously, the viewing angle is added to the C-arm system to optimize the 2D X-ray image.

Advantageously, the selection means 12 comprise means for detecting the medical instrument 4 within the 3D ultrasound data set 21. It should be noted that medical instruments usually appear with high contrast in the 3D ultrasound data set. This is for example the case of an electrophysiology catheter comprising a metal tip at its tip. The tip is a small and thin segment which is very echogenic and leaves a specific signature in the 3D ultrasound data set. So, either the tip end is seen as a punctate landmark, or the entire end is seen as an elongated landmark.

Thus, the detection means involve image processing techniques well known to those skilled in the art for enhancing high-contrast spots or elongated shapes in a relatively homogeneous background.

自动规定参考面30，其中点EP₁例如相应于医疗仪器的检测的末端，例如尖端31的末端，以及法线取向

相应于X射线源6的已知的取向32。The detection device allows orientation with point EP ₁ and normal

Automatic specification of a reference plane 30 in which the point EP ₁ corresponds, for example, to the end of the test of the medical instrument, for example the end of the tip 31 , and the normal orientation

This corresponds to the known orientation 32 of the x-ray source 6 .

，它可以有利地用来重新取向X射线源6，以使得X射线采集相对于医疗仪器4的检测位置最佳化.In an alternative, the reference plane 33 is defined by at least three non-aligned points EP ₁ , EP ₂ , EP ₃ given by the detection of the medical device 4 . specifies the second normal

, which can advantageously be used to reorient the X-ray source 6 to optimize the detection position of the X-ray acquisition relative to the medical instrument 4.

Referring to Fig. 6, it can be calculated from the knowledge of the geometric relationship of the X-ray acquisition device and the knowledge of the second position of the ultrasonic probe 9 within the X-ray reference range (0, x, y, z) provided by the conversion device 13 Mapping between points included in the reference plane 30 , 33 and points included on the 2D X-ray image 40 . For example, point _EP1 is projected on point P(EP1) on 2D X-ray image 40 according to projection line 36 .

The generation and display device 14 according to the invention is intended to generate a bimodal representation of the medical instrument in which information from 2D X-ray images and 3D ultrasound data sets are combined.

Preferably, such a combination is x-ray driven, which means that it is made from a 2D x-ray image 40, as shown in FIG. 7 .

In a first embodiment of the invention, the region of interest of the medical instrument is comprised in the reference planes 30 , 33 . The ultrasound information contained in the region of interest therefore corresponds to the 2D ultrasound image 41 obtained by sampling the 3D ultrasound data set on the reference plane 30 , 33 .

A bimodal representation is an image formed such that the intensity values of all points of the 2D X-ray projection 40 with corresponding points on the 2D ultrasound map 41 are combined. Such a combination is defined, for example, by a scalar function f of a first intensity value I ₁ of a point of the 2D x-ray image 40 and a second intensity value I ₂ of a corresponding point on the 2D ultrasound image 41 . Such a scalar function f provides an intensity value I, for example, by implementing the alpha-blending technique, well known to those skilled in the art, as follows:

I=f(I ₁ , I ₂ )=αI ₁ +(1-α)I ₂

If α is equal to 1, the intensity value I of the bimodal representation is equal to the first X-ray intensity I ₁ . Conversely, if α is equal to zero, the intensity value I of the bimodal representation is equal to the second ultrasound intensity I ₂ , which means that the intensity value of a point of the 2D X-ray image is replaced by the intensity value of the corresponding point of the 2D ultrasound image 41 .

The ultrasound acquisition device provides a 3D transmitted data set focused on the medical instrument. With the present invention, the combination of X-ray and ultrasound intensity values has the advantage of improving the visibility of the tissue surrounding the medical instrument.

Those skilled in the art will see that the projection of the medical instrument on the detector 7 given by the X-ray source 7 is of good quality and benefits from high resolution and contrast. When the region of interest of the 3D ultrasound data set When the detection of the medical instrument in the 2D X-ray projection 40 has been made available by the detection device, it can be obtained from the position of the medical instrument in the X-ray reference range (O, x, y, z) within the 2D X-ray projection 40—that is, in Within the detector reference range (dO, dx, dy) - the position of the projection of the medical instrument 4 . This position is, for example, the group 43 of points corresponding to the X-ray projection of the group of points 42 within the 2D ultrasound image 41 .

Advantageously, the intensity values of points belonging to the 2D X-ray projection 40 of the detected medical instrument are given as corresponding points of the bimodal representation. The advantage is to maintain good visibility and resolution of the medical instrument provided by the X-ray acquisition device.

In a second embodiment of the invention shown in FIG. 8, the system according to the invention also includes means for segmenting a region of wall tissue—for example, the endocardial wall near the medical instrument 4. This is achieved by means such as Image processing techniques such as thresholding of intensity values achieve this because wall tissue such as heart muscle appears brighter in ultrasound images than blood.

Another possibility is to detect boundaries, eg by using active contouring techniques (also called "snakes"). Known to those skilled in the art, this technique consists, firstly, of specifying an initial profile and, secondly, of allowing said initial profile to evolve under the influence of internal and external forces. Get the final contour 46. It is possible to distinguish points lying inside the contour 46 from points lying outside the contour 46 , giving only the intensity values of the corresponding points of the 2D sonogram 41 to the outside points. An advantage of this second embodiment is to benefit from the x-ray information in the larger surrounding part of the medical instrument 4 .

In a third embodiment of the invention shown in FIG. 9 , the system according to the invention also comprises means for generating a volume rendering image 51 of a defined region of interest 35 . In this example, region of interest 35 is slice 50 . The volume rendered image 51 is obtained by integrating the 3D ultrasound data according to one direction, eg the direction of the orientation of the X-ray acquisition device as indicated by the cylinder 52 . The volume rendering image 51 is used instead of the 2D ultrasound image 41 and combined with the 2D X-ray image 40 for generating a bimodal representation 53 in the same manner as previously described. The advantage of this third method is to provide a perspective view of the vicinity of the medical instrument 4, for example they are the heart.

It should be noted that the generating means 14 can generate the bimodal representation inversely from the 3D ultrasound data set and replace the X-ray information with ultrasound information. However, it is less favorable because in this case the bimodal representation has the image field reduced to one of the 3D ultrasound acquisition devices.

The system is intended to provide real-time 2D X-ray images and real-time 3D ultrasound data sets. Although the positioning of the probe has been performed in the proximal-interventional step, such position may have to be updated when patient motion occurs, especially if breathing motion has to be compensated. In fact, patient movement can cause changes in the position of the ultrasound probe within the X-ray reference range, so, in a fourth embodiment of the present invention, the system includes control means for periodically triggering the ultrasound probe for positioning the X-ray 330T means. Such triggering can be performed manually when the user judges this to be necessary, or automatically at regular intervals, retriggering the probe positioning for each new 2D X-ray image or 3D ultrasound data set acquired . It should be noted that in this case probe positioning must be performed in real time. The advantage is that it avoids any accumulation of errors when mapping 2D X-ray data with 3D ultrasound data.

In a fifth embodiment of the invention, the system comprises means for compensating for any relative movement of the ultrasound probe relative to the patient's heart during the time interval between two successive probe positions. These motion compensation means are intended to compensate for the difference between the current 3D ultrasound data set 3DUS(t _{0 +t) acquired at the current time t 0 + t} and the previous 3D ultrasound data set 3DUS(t ₀ ) acquired at the previous time t 0 The two ultrasound data sets correspond to the same phase of the heart cycle. First, estimate the motion vector linking the points of the current 3D ultrasound data set 3DUS(t ₀ +t) with the points of the previous 3D ultrasound data set 3DUS(t ₀ ) and shift the current 3D ultrasound data set according to the calculated motion vector 3DUS(t ₀ +t) points. Therefore, a motion compensated 3D ultrasound data set MC(3DUS(t ₀ +t)) is obtained, which is expected to be closer to the previous 3D ultrasound data set 3DUS(t0). In a first method, block-matching techniques well known to those skilled in the field of video compression are advantageously used. Referring to FIG. 10 , the figure shows the principle of block matching in the 2D situation for simplicity, the current and previous 3D ultrasound data sets 3DUS(t ₀ +t) and 3DUS(t ₀ ) are divided into blocks, for example, with 8 ×8×8 points, and for each block Bn ₁ of the current 3D ultrasound data set, a search is performed for block Bn ₀ of the previous 3D ultrasound data set, which leads to the maximum correlation value. get motion vector $\stackrel{\&Right\; Arrow;}{\mathrm{MV}}=\stackrel{\&Right\; Arrow;}{{\mathrm{<figure-callout\; id="1"\; label="Bn"\; filenames="C200480038283E00171.png"\; state="\{\{state\}\}">Bn</figure-callout>}}_1{\mathrm{<figure-callout\; id="0"\; label="Bn"\; filenames="C200480038283E00181.png"\; state="\{\{state\}\}">Bn</figure-callout>}}_0}.$

Therefore, the motion compensation means are intended to compensate small motions occurring between time t ₀ and time t ₀ +t on the current ultrasound image. It should be noted that motion compensation is effective when there are small differences between the two 3D ultrasound data sets. An advantage of the fifth embodiment of the present invention is that it provides for compensating A solution to positioning errors caused by small movements of the heart, which is compatible with real-time viewing. This solution is particularly advantageous when probe positioning cannot be performed in real time, eg when several angle views are involved by the C-arm. In this case, motion compensation means can advantageously be used while two successive probes are being positioned.

It should be noted that the system according to the invention is particularly advantageous for electrophysiological procedures involving the generation of electrically driven maps of the heart wall for diagnosis of cardiac disease or ablation of regions of wall tissue considered abnormal. In fact, the system according to the present invention facilitates the generation of electrical actuation maps by providing a large field of view for real-time viewing of the surgical field in which the medical instrument, bony structure and surrounding wall tissue are simultaneously visible.

The invention also relates to a method for introducing a medical device 4 into a patient. Referring to Figure 11, such a method includes the following steps:

- acquiring 60 two-dimensional x-ray images of said medical instrument by using an x-ray acquisition system,

- acquiring 61 a three-dimensional ultrasound data set of said medical instrument by using said probe,

- positioning 62 said ultrasound probe within a reference range of said X-ray acquisition system,

- selecting 63 a region of interest of said medical instrument within said 3D ultrasound data set and providing a first position of said region of interest within a reference range of an ultrasound acquisition device,

- transforming 64 said first position within said reference range of a 3D ultrasound data set into a second X-ray position within said reference range of an X-ray acquisition system,

- generating 65 and displaying a bimodal representation of said medical instrument, wherein 2D X-ray images and 3D ultrasound data comprised in said region of interest are combined using a second location.

The preceding figures and their description illustrate rather than limit the invention. It will be appreciated that there are many alternatives which fall within the scope of the appended claims. In this regard, the following concluding remark is made: There are many ways of implementing functions by means of hardware or software or both. Thus, although a drawing shows different functions as different blocks, this by no means excludes that a single item of hardware or software carries out several functions, or that a single function is carried out by components of hardware or software or both.

Any reference signs in a claim should not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element or step does not exclude the presence of a plurality of such elements or steps.

Claims (14)

1. medical system comprises:

-be directed to the intravital Medical Instruments of patient,

-X ray harvester is used to gather the two-dimensional x-ray images of described Medical Instruments,

-ultrasound acquisition means is used to use ultrasonic probe to gather the three-D ultrasound data group of described Medical Instruments,

-positioner is used to provide the position of described ultrasonic probe in the term of reference of described X ray harvester,

-selecting arrangement is used for being chosen in three-D ultrasound data group interesting areas around described Medical Instruments, and it is defined in the primary importance of the interior described area-of-interest of term of reference of described ultrasound acquisition means,

-conversion equipment, be used for the primary importance of described area-of-interest in the described term of reference of ultrasound acquisition means being transformed into the second position of described area-of-interest in the described term of reference of described X ray harvester by the described position of using ultrasonic probe

-generating apparatus is used to generate and shows that the bimodulus of described Medical Instruments represents, wherein said two-dimensional x-ray images and the three-D ultrasound data that is included in the described area-of-interest are combined by using the described second position.

2. the system that requires as in claim 1, the wherein said selecting arrangement that is used to select area-of-interest is arranged to limit the plane of reference comprising the part of described Medical Instruments.

3. as the system of requirement in claim 2, wherein said area-of-interest is the two-dimensional ultrasonic image that obtains by the described three-D ultrasound data group of sampling on the described plane of reference.

4. the system that requires as in claim 2, wherein said area-of-interest is to be in the three-D ultrasound data group of described plane of reference back or the section that forms by clip obtains by clip around the described plane of reference.

5. the system that requires as in claim 4, the volume that wherein said generating apparatus is arranged to be created on the described area-of-interest in the described three-D ultrasound data group presents view.

6. as the system of requirement in claim 1, wherein said positioner is arranged to locate the active localizer that is arranged on the described ultrasonic probe.

7. the system that requires as in claim 1, wherein said ultrasonic probe is equipped with at least three non-being mutually related to the radio frequency opaque markers of being arranged in a straight line, and described positioner is arranged to be positioned at the described labelling at least the first two-dimensional x-ray images that has first orientation angles in the described term of reference.

8. as the system of requirement in claim 7, wherein said positioner is arranged to be positioned at the described labelling on second two-dimensional x-ray images that has second orientation angles in the described term of reference.

9. the system that requires as in claim 1, wherein said selecting arrangement comprises the device of the described Medical Instruments in the described area-of-interest that detects the three-D ultrasound data group, and described generating apparatus is arranged to give the X ray intensity level of the point of the Medical Instruments of detection in described bimodulus is represented with the corresponding point on two-dimensional x-ray images.

10. the system that requires as in claim 1, comprise being used for the device of segmentation, and the described generating apparatus point of being arranged to belong to described wall tissue regions is with the ultrasound intensity value corresponding to the point of described area-of-interest at three-D ultrasound data group mesospore tissue regions.

11. as the system that requires in claim 1, wherein the X ray harvester is arranged to provide real-time two-dimensional x-ray images, and ultrasound acquisition means provides real-time three-dimensional ultrasound data group.

12. the system as requiring in claim 11 comprises being used for the control device of triggered location device periodically.

13. as the system that in claim 11, requires, comprise the device of the motion between the three-D ultrasound data group that is used to compensate before the current three-D ultrasound data group of gathering and the former time collection in the current time.

14. a method is used to produce and show the expression of Medical Instruments in the human body, may further comprise the steps:

-gather the two-dimensional x-ray images of described Medical Instruments by using the X ray acquisition system,

-by using the three-D ultrasound data group of ultrasonic probe and the described Medical Instruments of ultrasound acquisition system acquisition,

-be positioned at described ultrasonic probe in the term of reference of described X ray acquisition system,

-being chosen in the area-of-interest of described Medical Instruments in the described three-D ultrasound data group, it stipulates the primary importance of described area-of-interest in the term of reference of described ultrasound acquisition system,

-the described primary importance in the described term of reference of described ultrasound acquisition system is transformed into the second X ray position in the described term of reference of X ray acquisition system,

-generate and show that the bimodulus of described Medical Instruments represents that the two-dimensional x-ray images and the three-D ultrasound data that wherein are included in the described area-of-interest are combined by using the described second position.

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