Method and device for capturing diagnostically acceptable three-dimensional ultrasound image data records

• US 5,924,989 A
• Filed: 03/31/1997
• Issued: 07/20/1999
• Est. Priority Date: 04/03/1995
• Status: Expired due to Term

• Current Assignee: Echotech 3 D Imaging Systems GmbH
• Original Assignee: Hans Polz
• Inventors: Polz, Hans
• Primary Examiner(s): Jaworski, Francis J.
• Application Number:
  US08/828,582
• Time in Patent Office: 841 Days
• Field of Search: 600/443, 600/449, 128/916
• US Class Current: 600/443
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 8/13 Tomography A61B8/10, A61B8/12 take precedence; tomography for radiation diagnosis A61B6/02
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/543 involving acquisition triggered by a physiological signal
• CPC Class Codes: G01S 15/8936 using transducers mounted for mechanical movement in three dimensions
• CPC Class Codes: G01S 15/899 Combination of imaging systems with ancillary equipment
• CPC Class Codes: G01S 15/8993 Three dimensional imaging systems
• CPC Class Codes: G01S 7/52069 Grey-scale displays
• CPC Class Codes: G01S 7/52071 Multicolour displays; using colour coding; Optimising colour or information content in displays, e.g. parametric imaging
• CPC Class Codes: Y10S 128/916 Ultrasound 3-D imaging

Abstract

A method and apparatus for generating a diagnostically usable three-dimensional image data set is disclosed. The ultrasonic images generated from an ultrasonic apparatus are supplied to an image processing system which uses a position sensor system to determine the spatial location of the ultrasonic image in each dimension. The raw data are transformed into three-dimensional data set having numerous voxels with associated image or gray values, the image or gray values being formed for each voxel according to a preassigned algorithm, to wit from the image or gray values of those image points which are closest in each instance to the current voxel in the unit images or their image planes and whose distance from the current voxel does not exceed a preassigned maximum allowable distance.

Claims

1. A method of generating a diagnostically usable three-dimensional image data set (19) of a volume of a body under examination, said method comprising the steps of:

using an ultrasonic apparatus (6) with an ultrasonic head (7);

freely guiding said ultrasonic head (7) along said body under examination whereby a sequence of ultrasonic single images are generated in different image planes (BE1, BE2, BE3, BE4) of said volume to be examined;

transmitting said sequence of ultrasonic single images to an image processing system (1) connected to the ultrasonic apparatus;

determining the position and orientation of said ultrasonic head (7) and therefore the spatial location of the image plane of each ultrasonic single image, said determination being performed by a position sensor system (8) during generation of said sequence of ultrasonic single images, said position and orientation being determined in relation to the three degrees of freedom in translation and rotation, said sensor system (8) being an electromagnetic system whose receiver (10) is provided on said ultrasonic head (7);

transmitting said position and orientation data of said sensor system to said image processing system (1);

storing said ultrasonic single images as raw data together with an image header containing at least said position and orientation data, said raw data forming data set (18) consisting of a plurality of voxels (20);

forming a corresponding image or gray value for each voxel (20) according to a preassigned algorithm by measuring the image or gray values of those image points (20'"'"') which are closest in each instance to the current voxel (20) in the single images or their image planes (B1 to B4) and whose distance from the current voxel (20) does not exceed a preassigned maximum allowable distance (C) and using the measurements in said preassigned algorithm to determine said image or gray value for each voxel; and

transforming the locations of said voxels (20) to a common coordinate system and transforming said raw data set (18) into said three-dimensional data set (19), whereby the volume of the body under examination is tomographically captured.

2. Method according to claim 1 wherein the receiver (10) of said sensor system is provided on the ultrasound head (7) or on the holder (17) attached to the ultrasound head, and in that the image processing system (1) calibrates the position and orientation data supplied by the sensor system with the use of parameters that take into account the spatial relationship between the receiver (10) of the sensor system and its orientation in space and the location of the image plane of the ultrasound head (7).

3. Method according to claim 2 wherein the image processing system (1) calibrates the position and orientation data in a subsequent processing phase following the storing of said ultrasonic single images as raw data.

4. Method according to claim 2 wherein the image processing system (1) calibrates the position and orientation data during the storing of said ultrasonic single images as raw data, and in that the calibrated position and orientation data are stored in the respective image header.

5. Method according to claim 1 further comprising the steps of connecting an electrocardiograph to the image-processing system (1) generating a signal defining an ECG cycle such as a signal representing the R wave of the ECG cycle with said electrocardiograph, storing in the image header a value which represents the phase position between such a defined point in time of the ECG cycle and the input of an ultrasound single image in the image-processing system.

6. Method according to claim 5 wherein, for generating a three-dimensional static data record, the transmission of ultrasound images into the image-processing system (1) takes place synchronously with the ECG cycle, in each instance in a predetermined time window of the ECG cycle.

7. Method according to claim 5 further comprising the steps of generating a three-dimensional dynamic data record (19, 19'"'"'), transmitting ultrasound single images into the image-processing system (1) continuously, and storing the image values in the three-dimensional data record (19, 19'"'"') in accordance with the phase position in the ECG cycle in the image-processing system.

8. Method according to claim 1, characterized in that a device (13) for capturing the respiratory cycle is used, and in that a measured value, which determines the phase position in the respiratory cycle, is stored in the image header.

9. Method according to claim 1 characterized in that in the transformation, first the current voxel (20) or its position (coordinates) is selected according to a preassigned program routine, and then the image or gray value of the voxel (20) is formed.

10. Method according to claim 1, further comprising the step of fixedly preassigning the value (C) of the maximum allowable distance.

11. Method according to claim 1, further comprising the step of adjusting the value (C) of the maximum allowable distance.

12. Method according to claim 1 wherein the image or gray value for the current voxel (20) is formed by forming a weighted sum or a weighted average according to the formula

13. A device for generating a diagnostically usable three-dimensional image data set (19) of a volume of a body under examination, said device comprising:

an ultrasonic apparatus (6) with a freely guided ultrasonic head (7) which generates a sequence of ultrasonic single images in different image planes of (BE1, BE2, BE3, BE4) of the volume to be examined;

an image processing system (1) connected to the ultrasonic apparatus (6) to which system the sequence of ultrasonic single images is supplied;

a position sensor system (8) that determines the position and orientation of said ultrasonic head (7) and therefore the spatial location of the image plane of each ultrasonic single image, the location being determined in relation to the three degrees of freedom in translation and rotation, said sensor system (8) being an electromagnetic system whose receiver (10) is provided on said ultrasonic head (7);

means for transmitting said position and orientation data of said sensor system to said image processing system (1) in which said ultrasonic single images are first stored as raw data in this phase of data acquisition together with an image header containing at least said position and orientation data, said raw data forming data set (18) consisting of a plurality of voxels (20);

means for forming a corresponding image or gray value for each voxel (20) according to a preassigned algorithm by measuring the image or gray values of those image points (20'"'"') which are closest in each instance to the current voxel (20) in the single images or their image planes (B1 to B4) and whose distance from the current voxel (20) does not exceed a preassigned maximum allowable distance (C) and using the measurements in said preassigned algorithm to determine said image or gray value for each voxel; and

means for transforming the locations of said voxels (20) to a common coordinate system and transforming said raw data set (18) into said three-dimensional data set (19), whereby the volume of the body under examination is tomographically captured.

14. Device according to claim 13 wherein the receiver (10) of said sensor system is provided on the ultrasound head (7) or on the holder (17) attached to said ultrasound head, and in that the image processing system (1) has means for calibrating the position and orientation data supplied by the sensor system with the use of parameters that take into account the spatial relationship between the receiver (10) of the sensor system and its orientation in space and the position of the image plane of the ultrasound head (7).

15. Device according to claim 13, characterized in that the calibration of the position and orientation data is effected in a subsequent processing phase following the data-acquisition phase.

16. Device according to claim 14 wherein the image processing system (1) calibrates the position and orientation data during the storing of said ultrasonic single images as raw data, and in that the calibrated position and orientation data are stored in the respective image header.

17. Device according to claim 13 wherein an electrocardiograph is connected to the image-processing system (1) and generates a signal defining an ECG cycle such as a signal representing the R waves of the ECG cycle, where the image-processing system (1) has means for storing a value which represents the phase position between such a defined point in time of the ECG cycle and the input of an ultrasound single image in the image-processing system.

18. Device according to claim 17 wherein the means for transmitting transmits the ultrasound images into the image-processing system (1) synchronously with the ECG cycle, in a predetermined time window of the ECG cycle.

19. Device according to claim 17 wherein the means for transmitting transmits the ultrasound single images into the image-processing system (1) continuously, and the image-processing system has means for storing the image values in the three-dimensional data record (19, 19'"'"') in accordance with the phase position in the ECG cycle.

20. Device according to claim 13 further comprising a means (13) for capturing the respiratory cycle connected to said image processing system (1).

21. Device according to claim 13, further comprising a preassigned program routine for first selecting the current voxel (20) or its position and then forming the image or gray value of the voxel (20) during the transformation.

22. Device according to claim 13 further comprising means for fixing the value (C) of the maximum allowable distance.

23. Device according to claim 13 further comprising means for adjusting the value (C) of the maximum allowable distance.

24. Device according to claim 13 further comprising means for forming the image or gray value for the current voxel (20) by formation of a weighted sum or a weighted average according to the formula