Flexible image registration for rotational angiography
AssigneeSiemens Corporate Research, Inc.
InventorsAli Reza Bani-Hashemi, Sumitro Samaddar
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Abstract
A digital subtraction angiography method useful for processing a mask and contrast series of two dimensional (2D) images acquired by rotational imaging of a selected volume of a body. The method reduces image artifacts caused by misregistration, and is unique in that for registration purposes it treats the acquired 2D images as a volume. The individual 2D images are stacked in a sequence so as to have the dimensions x, y and .theta.. A flexible volume registration is then performed to bring the mask and contrast volumes into a close match prior to subtraction.
Claims18
A digital subtraction angiography method useful for rotational 2D imaging of a selected volume of a body, comprising the following steps:
- acquiring first and second volumes of 2D data sets representative of a series of rotationally offset 2D images of substantially the same selected volume in the body, the first and second data sets being acquired at different times corresponding to a pre- and a post, respectively, application of a process to the body to differentially affect imaging characteristics of the selected volume;
- determining common reference points for spatially corresponding sub-areas in each image of the series of rotationally offset 2D images in the first and second data sets;
- comparing in a 3D spatial manner data in sub-areas of the second data set with data in corresponding sub-areas in at least two of the rotationally offset 2D images of the first data set in order to determine a new reference point in each of the sub-areas of the first data set which results in a best match of the spatial similarity of the data in a corresponding sub-area of the second data set;
- spatially interpolating new data for sub-areas of the first data set using the new reference points determined above and the originally acquired data of the first data set, thereby generating a new first data set for the selected volume;
- and
- subtracting the new first data set from the second data set, thereby generating a subtraction data set representative of a series of 2D images of the selected volume in which the given portion is accentuated.
A digital subtraction angiography apparatus adapted for rotational 2D imaging of a selected volume of a body, comprising:
- means for acquiring first and second volumes of 2D data sets representative of a series of rotationally offset 2D images of substantially the same selected volume in the body, the first and second data sets being acquired at different times corresponding to a pre- and a post, respectively, application of a process to the body to differentially affect imaging characteristics of the selected volume;
- means for determining common reference points for spatially corresponding sub-areas in each image of the series of rotationally offset 2D images in the first and second data sets;
- means for comparing in a 3D spatial manner data in sub-areas of the second data set with data in corresponding sub-areas in at least two of the rotationally offset 2D images of the first data set in order to determine a new reference point in each of the sub-areas of the first data set which results in a best match of the spatial similarity of the data in a corresponding sub-area of the second data set;
- means for spatially interpolating new data for sub-areas of the first data set using the new reference points determined above and the originally acquired data of the first data set, thereby generating a new first data set for the selected volume;
- and
- means for subtracting the new first data set from the second data set, thereby generating a subtraction data set representative of a series of 2D images of the selected volume in which the given portion is accentuated.
Dependencies are inferred from the claim text.