Method and apparatus for reconstructing images from projection data acquired by a computed tomography system

A computed tomography (CT) system for reconstructing an image of an object from a plurality of x-ray projection images of the object, the x-ray projection images being acquired by the CT system, the CT system comprising:

• an x-ray source, the x-ray source projecting x-rays through the object;
• a detector, the detector detecting x-rays that pass through the object, the detector comprising a plurality of pixels, each pixel having a pixel value associated therewith, the detector generating projection data in response to the x-rays impinging thereon, the projection data corresponding to the intensity values;
• and
• logic receiving the projection data generated by the detector, the logic being configured to store the projection data in memory and to perform a rebinning process on the projection data, the rebinning process reducing the projection data from a first quantity of projection data to a second quantity of projection data, the logic being configured to perform a first reconstruction of an image of the object from the second quantity of projection data and to determine whether a second reconstruction is to be performed for a particular region of interest in the first reconstructed image, wherein if the logic determines that the second reconstruction is to be performed, the logic reads a portion of the first quantity of image data out of memory that corresponds to the particular region of interest and performs a second reconstruction of an image of the particular region of interest, the second reconstruction having a higher resolution than the first reconstruction.

A method for reconstructing an image of an object from x-ray projection data, the method comprising the steps of:

• acquiring the x-ray projection data with a computed tomography (CT) system, the CT system comprising an x-ray source and a detector, the detector comprising a plurality of pixels, each pixel having an intensity value, the x-ray source projecting x-rays through an object being imaged, the detector detecting x-rays that pass through the object, the detector generating the projection data in response to the x-rays impinging thereon;
• storing the projection data in memory;
• rebinning the projection data to reduce the projection data from a first quantity of projection data to a second quantity of projection data;
• performing a first reconstruction of an image of the object from the second quantity of projection data;
• determining whether a second reconstruction is to be performed for a particular region of interest in the first reconstructed image;
• wherein if a determination is made that the second reconstruction is to be performed, reading a portion of the first quantity of projection data out of memory that corresponds to the particular region of interest and performing a second reconstruction of an image of the particular region of interest, the second reconstruction having a higher resolution than the first reconstruction.

A computer program for reconstructing an image of an object from x-ray projection data, the projection data being acquired by a computed tomography (CT) system, the CT system comprising an x-ray source and a detector, the x-ray source projecting x-rays through the object, the detector detecting x-rays that pass through the object, the detector comprising a plurality of pixels, each pixel having an intensity value associated therewith, the detector generating projection data in response to the x-rays impinging thereon, the program being embodied on a computer-readable medium, the program comprising:

• a first code segment, the first code segment acquiring the x-ray projection data generated by the detector;
• a second code segment, the second code segment storing the projection data in a memory device;
• a third code segment, the third code segment rebinning the projection data to reduce the projection data from a first quantity of projection data to a second quantity of projection data;
• a fourth code segment, the fourth code segment performing a first reconstruction of an image of the object from the second quantity of projection data;
• a fifth code segment, the fifth code segment determining whether a second reconstruction is to be performed for a particular region of interest in the first reconstructed image;
• a sixth code segment, wherein if a determination is made that the second reconstruction is to be performed, the sixth code segment obtains a portion of the first quantity of projection data stored in the memory device that corresponds to the particular region of interest and performs a second reconstruction of an image of the particular region of interest, the second reconstruction having a higher resolution than the first reconstruction.