Method for detecting damage to silicone implants and computed tomography device

• US 9,211,066 B2
• Filed: 07/11/2013
• Issued: 12/15/2015
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Krau, Bernhard, Johnson, Thorsten
• Primary Examiner(s): Drennan, Barry
• Assistant Examiner(s): BEG, SAMAH A
• Application Number:
  US13/939,308
• Publication Number:
  US 20140064587A1
• Time in Patent Office: 887 Days
• Field of Search: None
• US Class Current: 1/1
• 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:

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;

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;

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;

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

determining if the data point or other value for each voxel of interest deviates from the known data points or values for body tissue by at least a first threshold value;

determining if the data point or other value for each voxel of interest deviates from the known data point or value for silicone by less than a second threshold value; and

outputting a warning if the data point or other value for each voxel of interest deviates from the known data points or values for body tissue by the first threshold value while the data point or other value for each voxel of interest simultaneously deviates from the known data points or values for silicone by less than the second threshold value.

2. The method of claim 1, wherein the comparing plots X-ray attenuation coefficients or CT values for each voxel of interest in a diagram and compares the data points with known values.

3. 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.

4. The method of claim 1, wherein the comparing includes,

determining at least one effective atomic number or an equivalent material density from the X-ray attenuation values, and

comparing each voxel of interest to known effective atomic numbers or equivalent material densities of body tissue and silicone.

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

6. The method of claim 5, 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.

7. 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.

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 another value for each voxel of interest determined from the X-ray attenuation values, with known data points or values of body tissue and known data points or values of silicone,

determine if the data point or other value for each voxel of interest deviates from the known data points or values for body tissue by at least a first threshold value,

determine if the data point or other value for each voxel of interest deviates from the known data point or value for silicone by less than a second threshold value, and

output a warning if the data point or other value for each voxel of interest deviates from the known data points or values for body tissue by the first threshold value while the data point or other value for each voxel of interest simultaneously deviates from the known data points or values for silicone by less than the second threshold value.

9. The computed tomography device of claim 8, wherein the system controller is configured to,

plot X-ray attenuation coefficients or CT values for each voxel of interest in a diagram, and

the data points are compared with known values.

10. 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.

11. The computed tomography device of claim 8, wherein, the system controller is configured to,

determine at least one effective atomic number or an equivalent material density from the X-ray attenuation values, and

compare each voxel of interest to known effective atomic numbers or equivalent material densities of body tissue and silicone.

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

13. The computed tomography device of claim 12, 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.

14. 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.