WO2011138172A1

WO2011138172A1 - Method for generating medical 3d image data

Info

Publication number: WO2011138172A1
Application number: PCT/EP2011/056371
Authority: WO
Inventors: Rainer Graumann; Gerhard Kleinszig
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-05-06
Filing date: 2011-04-20
Publication date: 2011-11-10
Also published as: DE102010019645A1

Abstract

The invention relates to a method for generating medical 3D image data (34) of a treatment target (14) in a patient (8), comprising the following steps: a) at a first time (T1) before or during a treatment of the patient (8), a 3D image data set (24) of the treatment target (14) is generated, b) at a later second time (T2) during the treatment, at least one 2D radioscopy image (26) of the treatment target (14)is generated with the aid of an imaging device (16), wherein said image contains an object (22) which has a known geometry and which can be displayed at least partially in the 2D radioscopy image (26), c) a transformation rule (32) between the 3D image data set (24) and the 2D radioscopy image (26) is determined, d) using the object (22) displayed in the 2D radioscopy image (26), the spatial position of said object is determined in the coordinate system of the imaging device (16), and image information representing the position is combined on the basis of the transformation rule (32) at the correct location with the 3D image data set (24) to form 3D image data (34), and e) in case of a change in the relative position (R) between treatment target (14) and object (22), steps b) to d) are repeated.

Description

description

Method for generating medical 3D image data The invention relates to a method for generating medical 3D image data.

Medical image data are generated by a patient by imaging, ie examining, at least a part of the patient's body in the image data. Image data are for example a two-dimensional (2D) x-ray image or a dreidi ^{¬-dimensional} (3D) magnetic resonance image in the form of 3D image data or a 3D image data set. Is performed on the patient to me ^¬ dizinische treatment, the treatment usually takes place locally; eg in the context of an operation as

Treatment at the hip of the patient to be placed an implant. The hip region of the patient and their surroundings - sometimes even outside the patient - then represent the treatment goal in the patient. Relevant medical measures, eg the provision of instruments or implants or the actual intervention in the body of the patient, are carried out there. The image data is usually generated by the treatment goal, especially because here Bildinfor ^¬ mation wishes overall by the patient and implants or tools is. Importantly often the knowledge of the relative posi ^¬ tion of tools and patient anatomy. This serves to decorate the medical tools locally accurately on the patient to plat ^¬ to, for example, to place a hole or an implant location right in the patient. As a rule, the anatomy of the patient is completely described by 3D image data of the treatment target.

The spatially correct positioning of surgical instruments and implants for open or minimally invasive procedures on patients still represents a not completely solved problem. In particular, for example, by minimizing the engagement trauma direct visibility to the Operations ^¬ targeted only been very limited. The direct view on The operation goal is - eg in the so-called button ^¬ hole surgery - only by an endoscope or its Videokame ^¬ ra. A fluoroscopy of the patient - usually X-ray imaging - is therefore often takes place.

A pure 2D imaging in many cases this is not sufficient, for example, decorate a correct implant position to verifi ^¬, especially for degenerative or abnormal anatomy of the patient.

It is known to use 2D or 3D X-ray imaging, ultrasound or endoscopy to generate medical image data. Also known is the use of 2D or 3D navigation with or without imaging to place an implant or instrument at a desired position in or on the patient. Known here is e.g. the system "CAPPA C-Nav" of the company "CAS innovations".

Also known is an image-based 2D method using ^Nut¬ tion of additional information. As additional information eg geometric information from or about tools, ie instruments or implants are used. Such a process is known from products of Surgix.

The object of the present invention is to specify an improved method for generating 3D medical image data.

The object is achieved by a method for generating medical 3D image data of a treatment target in a patient, with the following steps: In a step a), a 3D image data set of the treatment target is generated at a first time before or during the treatment of a patient. It will be a pre- or made intra-operative 3D image of the treatment or surgery ^¬ area.

At a later second point in time, in a step b), during the treatment with the aid of an imaging device, at least one - as a rule also several - 2D

Radiation image of the treatment goal generated. In other words, real-time or real-time 2D

Transillumination and projection photographs taken. This is called fluoroscopy in the case of X-rays. In this case, the treatment target contains an object (22) of known geometry that can be at least partially imaged in the 2D fluoroscopy image (26).

In a step c), a transformation rule is determined between the 3D image data record and the 2D fluoroscopic image. Thus, the 2D / 3D transformation between the 3D image data set and the real-time 2D projection exposure is calculated. In a step d) is then determined on the basis of the

Radiated image imaged object whose spatial La ^¬ ge in the coordinate system of the imaging device (16) determined. A location representing image information is then combined at ^¬ hand the transformation rule stationary properly with the 3D image data set to the 3D image data.

The known geometry makes it possible to determine the SD location information from the image of the object, since the relative geometric position of characteristic points of the object in the 2D image is recognizable.

In a step e), the steps b) to d) are repeated when the relative position between the treatment target and the object changes. In other words, the above Bildregistrie- tion between 2D fluoroscopic image and 3D image data set is per ^¬ recalculated weils if the geometries between the preoperative 3D image and the imaging device, ie between 2D and 3D change. This could be done, for example, by an object movement, Thus, the movement of the patient or the operation target ge ^¬ Schehen. Possible movements in or on the patient can be detected in a known manner, for example by a marker affixed to the patient and his location tracking, for example in 2D X-ray images taken after each other.

The problem of the invention can be solved very easily by the above-mentioned tech ^¬ nology associated with the above sequence. The inventive method is a simple method on the 2D fluoroscopy image position information of the object to ge ^¬ Visa, for example, the visible image in a 2D x-ray current implant or instrument position. The 3D position of the implant or instrument is then also known through the 2D-3D transformation and can be made available to the user, for example, in relation to the preoperative or intraoperative 3D patient anatomy. The user is therefore offered SD information.

This provides intra-operatively an easy way for encryption addition, how to pose no additional navigation devices posi ^¬ tions and orientations of implants and tools in the 3D data set or it can currently show in the preoperative 3D image. Each time a Aktualisie ^¬ tion of the location information, so an update may be performed) and the above-mentioned recycling by re-2D Durchleuchtungsaufnähme according to step b.

The use of a single 2D fluoroscopic image ranges e.g. then to the 3D position determination of the object, if it has enough reference points or characteristic in the 2D image locatable points in a known geometric relationship to each other, which allow a 3D location based on a 2D image. Methods for this are e.g. from image processing or mono-camera navigation systems known.

In this case, the image information can be, for example, an abstract mark such as a crosshair, a symbol of the object, an outline or the like. In a preferred embodiment of the method, however, an image of the object is combined with the 3D image data record in the correct location in step d) as image information on the basis of the transformation rule.

If the geometry of the object itself known in its entirety or materiality ^¬ union structural parts, this information can be used, for example, together with the known projection geometry of Bildge- exercise device. The projection geometry can - if not known - also be determined by known methods. Thus, 3D spatial coordinates of the object or characteristic points of it can actually be determined in the coordinate system of the 3D image data set and thus in the image data. It is then possible, even abstract information about the object, for example, represent a marker cross for an implant bore or a virtual projection line of a Bohrermit ^¬ center axis in the 3D image data. In preferred embodiments, the object used is an implant and / or an instrument of known geometry.

If, in an alternative embodiment, the geometry of the instrument and / or implant itself is not known, this can be equipped with markers detectable in the 2D fluoroscopy image, in which case the geometry of the markers or their relative arrangement must be known.

In other words, for example, markers or marker arrangements of known geometries are fastened or integrated on the tools or implants, for example on K-wires. These can then be used to calculate the 3D geometries in the coordinate system of the 2D fluoroscopic images, ie projection images. Implants can be used, for example, by their 3D geometries known from design drawings directly for the calculation of 3D positions and orientations in the coordinate system of the 2D projection capture. Finally, the position and orientation of the tools or implants in the coordinate system of the 2D projection receptacle, and thus in the coordinate system of the imaging device, for example an X-ray C-arm, is known. So can be pre ^¬ operative 3D image or the 3D data, and finally transmitted to the generated image data, the ak ^¬ tual position of the implant or of the tool in the ektionsaufnahmegerät result of the known transformation between 2D Proj and therefore 3D image -record ,

In a preferred embodiment, a 3D image containing planning data is used as the 3D image. The fiction, ^¬ contemporary approach can be combined with planning data, for example, have been obtained from the preoperative 3D dataset.

In addition, with such a method then e.g. Planned access routes and / or target and Entrypunkte in the second time, so currently obtained 2D projection images show and serve the surgeon as a reference point for the procedure. Alternatively or additionally, e.g. the deviation of the current position of an implant from a preoperatively planned implant position is calculated and made available to the surgeon.

If the 3D data set, that is to say the 3D image, is acquired intraoperatively at the first time by means of a 3D C-arm, then under certain circumstances the 2D / 3D image registration according to step c) can be performed very simply. The transformation specification is then given by the ^acquisition geometry or de ^¬ ren determination can strictly speaking be omitted if the 2D fluoroscopic images are obtained in a known to the 3D image data acquisition geometry. For a further description of the invention, reference is made to the ^exemplary embodiments of the drawing. It shows, in a schematic outline sketch: Fig.l the treatment of a patient and the generation of medical image data.

FIG. 1 shows a medical work station 2, which essentially comprises an imaging system 4, here an X-ray system and a patient table 6. On the patient table 6, a patient is positioned 8 to which the medical treatment Be ^¬ an intervention on the spine 10 to be performed. Therefore, a thoracic vertebra 12 and its immediate ambient represents the target area for treatment, therefore, the goal of treatment 14th This is in other words, in ^¬ teressierende (ROI, region of interest) of the patient 8, of which an imaging in the form of medical image data.

Imaging system 4, as imaging device 16, includes an X-ray C-arm that is capable of producing both 2D and 3D image data. Corresponding necessary for the imaging, as well as necessary for carrying out the method according to the invention calculation, processing or sons ^¬ term data processing steps take place in a computing unit 18 of the imaging system 4. The image data generated and Sons ^¬ term are displayed on screens 20 of the Bildgebungssys ^¬ tems. 4

The medical measure is carried out with a needle as a medical instrument or object 22.

At a first time Tl is from patient 8 and 16, a 3D image data set generated to the treatment target 14 by means of the imaging device 24 in the form of an X-ray, which includes the thoracic vertebrae 12 to be treated three-dimensionally maps and the corresponding the treatment target 14 lie ^¬ constricting part of the Spine 10 shows.

In an alternative embodiment, the SD image data set 24 is already on the patient's 8 at the time Tl, for example, with a magnetic resonance tomograph.

During the treatment, at least one 2D fluoroscopic image 26 from the treatment target 14, or e.g. multiple images in different rotational positions of the x-ray C-arm of the imaging device 16, i. from different perspectives on the treatment goal 14, created. The at least one 2D fluoroscopic image 26 allows in one

Coordinate system 28 of the imaging device 16, the spatial determination of the position of the in the 2D fluoroscopic image 26 gebil ^¬ Deten objects, in particular the thoracic vertebrae 12 and the Ob ^¬ jects 22nd

The computing unit 18 determines in a calculation step 30 a transformation rule 32, such as e.g. within the coordinate system 28 - the 2D fluoroscopic image 26 or the objects imaged therein are spatially related to the 3D image data set 24.

In the 3D image data set 24, an image information is now displayed, which represents the position of the object 22. In the case of ^¬ this is a real image - in an alternative embodiment of at least a part - of the object 22. This results in 3D image data 34th

In an alternative embodiment of the method is not the image of the object 22 itself, but only an abstract symbol or image 36 of which, namely shown in the form shown in Fig. 1 dashed line. The line is an imaginary image of the object 22 in the sense that this represents the profile of the needle when it is in the currently supported ^¬ requested direction advanced in the direction of its central longitudinal axis in the patent tienten.

In an alternative embodiment, the object 22 also has an array of instruments with the imaging device as an instrument 16 detectable, so here radiopaque markers 38, which are shown in particular in the 2D fluoroscopic images 26 with. In this embodiment, the projection geometry of the imaging device 16 is determined on the basis of the marker 38 imaged in the 2D drone illumination image 26. Also, the location of the object 22 in the coordinate system of the Bildge ^¬ exercise device 16 is not determined based on the image of the object 22 itself, but the image of the marker 38th The Geo ^¬ geometry of the object 22 then does not need to be known.

In an alternative embodiment, the object 22 is a dashed-line implant to be ^inserted into the patient during the treatment. This was previously planned in advance in the 3D image data record 24 in the form of planning data 40, ie its planned position determined. In the image data 34, in this case, both the

X-ray images 26 shown actual implant 22 and the position of the implant 22 in the form of the planning data 40 simultaneously displayed, whereby the viewer of the image data 34 can check a deviation between the planned and real location.

If a relative position R between fluoroscopic device 16 and treatment target 14 changes, new 2D fluoroscopic images 26 are taken at a renewed time T2 and, as explained above, new 3D image data 34 is generated or refreshed with altered image contents.

The relative position R changes, for example, by the movement of the thoracic vertebra 12, of the entire patient 8 or of the object 22. Reference sign list

2 workstations

4 imaging system

6 patient table

8 patient

10 spine

12 thoracic vertebrae

14 treatment goal

16 imaging device

18 arithmetic unit

20 screen

22 object

24 3D image data set

26 2D fluoroscopic image

28 coordinate system

30 calculation step

32 transformation rule

34 3D image data

36 image

38 markers

40 planning data i, 2 time

R relative position

Claims

claims

A method of generating 3D medical image data (34) of a treatment target (14) in a patient (8), comprising the steps of:

a) at a first time (T1) before or during a treatment of the patient (8), a 3D image data record (24) of the treatment target (14) is generated,

(b) at a later second point of time T2) during loading action is (with the aid of an image forming apparatus 16) Min ^¬ least a 2D fluoroscopy image (26) of the treatment target (14) (in the 2D X-ray image 26) at least in part ^¬ example, imageable object (22) of known geometry contains generated,

c) between the 3D image data set (24) and the 2D

X-ray image (26) a transformation rule (32) is determined

d) shown on the basis of (in the 2D X-ray image 26) Whether ^¬ jekts (22) is determined whose spatial position in the coordinate system of the imaging device (16), and the location rep ^¬ räsentierende image information (based on the transformation rule 32) stationary properly with the 3D Image data set (24) merged into SD image data (34),

e) when a relative position (R) between the treatment target (14) and the object (22) changes, steps b) to d) are repeated.

2. The method of claim 1, wherein in step d) as image information, an image (36) of the object (22) with the SD image data set (24) is merged.

3. The method according to any one of claims 1 to 2, wherein as an object (22) an implant and / or instrument of known Geo ^¬ metry is used.

4. The method according to any one of claims 1 to 2, wherein as an object (22) with a marker (38) of known geometry equipped ^¬ implanted implant and / or instrument is used.

5. The method according to any one of the preceding claims, wherein as a 3D image data record (24) a planning data (40) containing 3D image data set (24) is used.