METHOD FOR DETECTING DAMAGE TO SILICONE IMPLANTS AND COMPUTED TOMOGRAPHY DEVICE

• US 20140064587A1
• Filed: 07/11/2013
• Published: 03/06/2014
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Klinikum der Universität München, Siemens AG
• Inventors: KRAU, Bernhard, JOHNSON, Thorsten
• Granted Patent: US 9,211,066 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: A61B 5/4851 Prosthesis assessment or monitoring
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/12 Arrangements for detecting or locating foreign bodies
• CPC Class Codes: A61B 6/482 involving multiple energy imaging
• CPC Class Codes: A61B 6/5205 involving processing of raw data to produce diagnostic data
• CPC Class Codes: G06T 2207/10081 Computed x-ray tomography [CT]
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30068 Mammography; Breast
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

A method is disclosed for detecting damage to silicone implants. In an embodiment, the method includes taking at least two computed tomography recordings at different X-ray spectra or different mono-energies of the X-ray radiation and reconstruction thereof. A data point is determined in a diagram for each voxel of interest, the X-ray attenuation values for different X-ray energies being plotted against one another; The data point, or another value for each voxel of interest determined from the X-ray attenuation values, is compared to known data points or values of body tissue and/or of silicone, and a note or warning is output if the data point or other value deviates from the known data points or values for body tissue by at least a first threshold value and/or in the event of simultaneous approximation to the known data point or value for silicone by less than a second threshold value.

Claims

1. A method for detecting damage to silicone implants in an object region of a human body using a computed tomography device, the method comprising:

a) taking at least two computed tomography recordings of the object region, each at different X-ray spectra or different mono-energies of the X-ray radiation;

b) reconstructing the at least two computed tomography recordings to form 3D data sets which contain X-ray attenuation values or equivalent material densities in terms of a basic material decomposition of voxels of the object region;

c) determining a data point in a diagram for each voxel of interest, the X-ray attenuation values for different X-ray energies being plotted against one another;

d) comparing the data point, or of another value for each voxel of interest determined from the X-ray attenuation values, with known data points or values of at least one of body tissue and silicone; and

e) outputting a note or warning if at least one of

the data point or other value deviates from the known data points or values for body tissue by at least a first threshold value, and

in the event of simultaneous approximation to the known data point or value for silicone by less than a second threshold value.

2. The method of claim 1, wherein the attenuation coefficients or the CT values for each voxel of interest being plotted in a diagram and the data points are compared with known values.

3. The method of claim 1, wherein, at least one effective atomic number or an equivalent material density is determined from the X-ray attenuation values and for each voxel of interest, is compared to the known effective atomic numbers or equivalent material densities of at least one of body tissue and silicone.

4. The method of claim 1, wherein any combination of soft tissue and fat are used as comparison values for the body tissue.

5. The method of claim 4, wherein a note or warning is output if at least one of

a perpendicular distance of the data point from a connecting straight line between the known data points of soft tissue and fat exceeds the first threshold value, and

a second threshold value for the known data point for silicone is simultaneously exceeded.

6. The method of claim 1, wherein three or more computed tomography recordings of the object region are taken at different radiation spectra or different mono-energies of the X-ray radiation.

7. The method of claim 2, wherein the CT values of the different X-ray energies are mapped to a measured variable by interpolation of precalculated table values.

8. A computed tomography device, comprising:

a dual-energy recording unit configured to record at least two computed tomography recordings of the object region at different radiation spectra or different mono-energies of the X-ray radiation; and

a system controller including a computing unit, configured to reconstruct the computed tomography recordings to form 3D data sets which contain X-ray attenuation values or equivalent material densities in terms of a basic material decomposition of voxels of the object region and configured to

determine a data point in a diagram for each voxel of interest, the X-ray attenuation values for different X-ray energies being plotted against one another, compare the data point, or of another value for each voxel of interest determined from the X-ray attenuation values, with known data points or values of at least one of body tissue and silicone, and

output a note or warning if at least one of

the data point or other value deviates from the known data points or values for body tissue by at least a first threshold value, and

in the event of simultaneous approximation to the known data point or value for silicone by less than a second threshold value.

9. The computed tomography device of claim 8, wherein the attenuation coefficients or the CT values for each voxel of interest being plotted in a diagram and the data points are compared with known values.

10. The computed tomography device of claim 8, wherein, at least one effective atomic number or an equivalent material density is determined from the X-ray attenuation values and for each voxel of interest, is compared to the known effective atomic numbers or equivalent material densities of at least one of body tissue and silicone.

11. The computed tomography device of claim 8, wherein any combination of soft tissue and fat are used as comparison values for the body tissue.

12. The computed tomography device of claim 11, wherein a note or warning is output if at least one of

a perpendicular distance of the data point from a connecting straight line between the known data points of soft tissue and fat exceeds the first threshold value, and

a second threshold value for the known data point for silicone is simultaneously exceeded.

13. The computed tomography device of claim 8, wherein three or more computed tomography recordings of the object region are taken at different radiation spectra or different mono-energies of the X-ray radiation.

14. The computed tomography device of claim 9, wherein the CT values of the different X-ray energies are mapped to a measured variable by interpolation of precalculated table values.