Image postprocessing method for removing metal artifact from computed tomography (CT) image

Abstract

The invention relates to an image postprocessing method for removing a metal artifact from a computed tomography (CT) image, which comprises the following steps of: converting an original CT image into a polar coordinate image from an orthogonal coordinate image; determining a metal projection region in the polar coordinate image; establishing a model in the polar coordinate image; performing model correction by adopting the model; correcting front and back projection errors brought into the model correction; and converting the polar coordinate image into the orthogonal coordinate image. According to a model establishing method provided by the invention, the good model can be established, and finally, a good correction result can be obtained; the errors brought in by front and back projection are corrected, so that the result after the correction is better, and the processing speed is ensured.

Description

technical field [0001] The invention relates to a CT image processing technology in the medical field, in particular to an image post-processing method for removing metal artifacts in a CT image. Background technique [0002] Clinically, if the scanned fault contains metal, due to the high attenuation characteristics of the metal to X-rays, the corresponding channel value passing through the metal has serious measurement errors (this paper refers to such a channel as a damaged channel). Make the reconstructed image produce something like figure 1 Artifacts are shown, which appear primarily as black and white streaks emanating from the metal and radial lines that fill the image. [0003] figure 2 It is the raw data before weighting and convolution at a certain viewing angle, and the peak part is the corresponding part passing through the denture. The larger the area of ​​the denture, the wider the corresponding peak; the denser the denture, the longer the denture the ray ...

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Problems solved by technology

[0014] (2) For the multi-slice CT using the 3D reconstruction algorithm, this method needs to process a large amount of projection data, and it faces great difficulties in terms of processing effect and processing efficiency

[0020] (1) The better method in image domain processing is the model-based correction method, but because the established models are very poor, the final correction result is also very poor, there are still artifacts that have not been removed, and even introduced new Artifacts, the processed results are still unusable for clinical diagnosis

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