摘要:
In three-dimensional rotational x-ray coronary imaging problems may arise when estimating the motion of small vessels. According to an exemplary embodiment of the present invention, an examination apparatus is provided which is adapted for performing a hierarchical motion estimation by global affine transformation for every heart phase, followed by vessel branch selective affine and non-affine transformations. This may provide for an improved image quality.
摘要:
The analysis of a stenosis of a coronary vessel in three dimensions requires a motion compensated reconstruction. According to an exemplary embodiment of the present invention, an examination apparatus for local motion compensated reconstruction data set is provided, wherein the local motion compensated reconstruction vectors relating to a start point and an end point of the stenosis.
摘要:
For the reconstruction of the coronary arteries from rotational coronary angiography data, a crucial point is the selection of the optimal cardiac phase for data reconstruction. According to an exemplary embodiment of the present invention, an automatic approach for deriving optimal reconstruction windows is provided by fully automatically selecting the optimal cardiac phase on the basis of a delayed acquisition protocol where at least one heart phase needs to be acquired in a static projection geometry.
摘要:
For the reconstruction of the coronary arteries from rotational coronary angiography data, a crucial point is the selection of the optimal cardiac phase for data reconstruction. According to an exemplary embodiment of the present invention, an automatic approach for deriving optimal reconstruction windows is provided by fully automatically selecting the optimal cardiac phase on the basis of a delayed acquisition protocol where at least one heart phase needs to be acquired in a static projection geometry.
摘要:
A method is provided for analysis of a multi-dimensional structure which includes a tubular structure from two-dimensional datasets for respective pre-determined projection directions. A pair of corresponding initial projected centre points of the tubular structure is identified in two respective initial and further two-dimensional datasets. Projected edges of the tubular structure in said initial two-dimensional datasets and in said further two-dimensional dataset near the respective projected centre points are identified. A local size of the tubular strucwur is derived at the three-dimensional spatial position of the centre point of the tubular structure from said projected edges and the predetermined projection directions.
摘要:
A method is provided for analysis of a multi-dimensional structure which includes a tubular structure from two-dimensional datasets for respective pre-determined projection directions. A pair of corresponding initial projected centre points of the tubular structure is identified in two respective initial and further two-dimensional datasets. Projected edges of the tubular structure in said initial two-dimensional datasets and in said further two-dimensional dataset near the respective projected centre points are identified. A local size of the tubular structure is derived at the three-dimensional spatial position of the centre point of the tubular structure from said projected edges and the predetermined projection directions.
摘要:
E.g. in cardiac cone-beam CT, the source path is interrupted due to the fact that the projection data is gated. According to the present invention, a method is provided to obtain projection data corresponding to an uninterrupted source trajectory from such a gated data set. For this purpose, a motion compensation is applied. Advantageously, a complete data set may be determined allowing for an approximate or an exact reconstruction method to be applied to the completed data set without interruption of the image generation.
摘要:
It is described a method for acquiring a series of two-dimensional X-ray attenuation data of an object under examination (310) by means of an X-ray imaging apparatus (100) having a rotatable scanning unit (301). In order to increase the angular range of the scanning unit (301), when a region of interest (HOa) located not in the center of the object (310) is examined the object under examination (310) is shifted such that the region of interest is temporarily positioned outside the center of rotation. By coupling the rotational movement of the scanning unit (301) with the translative movement of the object (310) in a synchronized manner a collision between the scanning unit (301) and the object (310) can be effectively avoided. By employing an automated motorized object table (312) a precise pre-determined movement of the object (310) can be achieved during the data acquisition. By using an appropriate phantom based calibration procedure carried out with the same table movements known three-dimensional reconstruction algorithm can be directly applied in order to generate a three-dimensional representation of the region of interest (110a).
摘要:
A method for the three-dimensional reconstruction of an object, or its surroundings, in a moving body volume of a patient includes obtaining a series of X-ray projection photographs produced from different directions, with a relevant ECG phase or respiration being recorded simultaneously. Projection photographs of the moving body volume are transformed such that the images of feature points that are located on the projection photographs respectively come to rest at a place on which randomly set spatial reference positions for the feature points are projected. With the projection photographs aligned onto the reference positions, three-dimensional reconstruction of the object can subsequently take place.
摘要:
It is described a method for acquiring a series of two-dimensional X-ray attenuation data of an object under examination (310) by means of an X-ray imaging apparatus (100) having a rotatable scanning unit (301). In order to increase the angular range of the scanning unit (301), when a region of interest (HOa) located not in the center of the object (310) is examined the object under examination (310) is shifted such that the region of interest is temporarily positioned outside the center of rotation. By coupling the rotational movement of the scanning unit (301) with the translative movement of the object (310) in a synchronized manner a collision between the scanning unit (301) and the object (310) can be effectively avoided. By employing an automated motorized object table (312) a precise pre-determined movement of the object (310) can be achieved during the data acquisition. By using an appropriate phantom based calibration procedure carried out with the same table movements known three-dimensional reconstruction algorithm can be directly applied in order to generate a three-dimensional representation of the region of interest (110a).