Thermography image correction apparatus and method
Certain embodiments provide a medical image processing apparatus comprising processing circuitry configured to: receive a thermography image, or a pair of medical images from which a thermography image is obtainable; estimate a temperature field corresponding to the thermography image or pair of medical images; and generate a corrected thermography image based on the thermography image or pair of medical images and on the estimated temperature field.
1 . A medical image processing apparatus, comprising:
processing circuitry configured to:
receive a thermography image, or a pair of medical images from which a thermography image is obtainable;
estimate a temperature field corresponding to the thermography image or the pair of medical images, by fitting the estimated temperature field to the thermography image by optimizing one or more function parameters of the estimated temperature field; and
generate a corrected thermography image based on the thermography image or the pair of medical images and on the estimated temperature field, by performing smoothing of the thermography image or the pair of medical images by determining a gradient of temperature in the estimated temperature field, and performing a smoothing procedure comprising smoothing in a direction orthogonal to the gradient of temperature.
2 . The apparatus according to claim 1 , wherein the thermography image comprises a subtraction image obtained by subtracting a first CT image acquired at a first time and a second CT image acquired at a second, different time.
3 . The apparatus according to claim 1 , wherein the pair of medical images comprises a first CT image acquired at a first time and a second CT image acquired at a second, different time, and
wherein the processing circuitry is further configured to generate the corrected thermography image by
generating a corrected first CT image based on the estimated temperature field;
generating a corrected second CT image based on the estimated temperature field; and
subtracting the corrected first CT image and the corrected second CT image to obtain the corrected thermography image.
4 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to optimize the one or more function parameters by minimizing a difference between the estimated temperature field and the thermography image or the pair of medical images.
5 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to estimate the temperature field by selecting a part of the image for use in the optimizing, and performing the optimizing based on the selected part of the image.
6 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to generate the corrected thermography image by smoothing the thermography image or smoothing each medical image of the pair of medical images, and wherein a degree of smoothing used in the smoothing of the thermography image or the pair of medical images is selected by a user.
7 . The apparatus according to claim 1 , wherein the thermography image or the pair of medical images relate to an ablation process performed on tissue of a subject.
8 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to estimate the temperature field based on at least one heating parameter related to an application of heat to tissue imaged in the thermography image or the pair of medical images.
9 . The apparatus according to claim 8 , wherein the at least one heating parameter comprises at least one of a probe position, a probe power, a probe parameter, an ablation time, an electric field parameter, a rate of heat deposition, a tissue type, or a tissue geometry.
10 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to estimate the temperature field using an analytic function expression.
11 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to estimate the temperature field using a simulation of heat diffusion.
12 . The apparatus according to claim 11 , wherein the simulation of the heat diffusion uses at least one of a finite element method or a data-driven surrogate model.
13 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to estimate the temperature field using a look-up table.
14 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to generate the corrected thermography image by applying to the thermography image or the pair of medical images at least one of:
a spatially-dependent averaging procedure;
a spatially-dependent isotropic smoothing procedure;
a spatially-dependent anisotropic smoothing procedure;
a 3D conditional random field inference procedure; or
anisotropic diffusion.
15 . The apparatus according to claim 1 , wherein the processing circuitry is further configured to receive a thermography image and at least one further thermography image, and estimate the temperature field by fitting the temperature field to the thermography image and to the further thermography image.
16 . The apparatus according to claim 15 , wherein the thermography image and the further thermography image are representative of different times, and
the fit the temperature field to the thermography image and to the further thermography image by determining a first value for at least one function parameter of the estimated temperature field in relation to the thermography image and a second, different value for the at least one function parameter of the estimated temperature field in relation to the further thermography image.
17 . The apparatus according to claim 1 , wherein the thermography image is a magnetic resonance (MR) thermography image and the corrected thermography image is a corrected MR thermography image.
18 . A medical image processing method, comprising:
receiving a thermography image, or a pair of medical images from which a thermography image is obtainable;
estimating a temperature field corresponding to the thermography image or the pair of medical images, by fitting the estimated temperature field to the thermography image by optimizing one or more function parameters of the estimated temperature field; and
generating a corrected thermography image based on the thermography image or the pair of medical images and on the estimated temperature field, by performing smoothing of the thermography image or the pair of medical images by determining a gradient of temperature in the estimated temperature field, and performing a smoothing procedure comprising smoothing in a direction orthogonal to the gradient of temperature.