Method of producing cardiac tomogram and tomograph using x-ray ct apparatus
First Claim
1. A method of producing a cardiac tomogram using an X-ray CT apparatus performing helical scans which has multiple columns of X-ray detector in a slicing direction of an object to be examined and using projection data detected by the X-ray detector, comprising the steps of:
- measuring electrocardiographic information of the object;
calculating a number of projection data to be divided necessary for reconstruction of a tomogram in each of the helical scan;
collecting divided projection data in an identical heartbeat time phase on the basis of the number of projection data to be divided and an electrocardiographic cycle obtained in the step of measuring the electrocardiographic information, and forming projection data necessary for reconstruction of a tomogram;
interpolating a discontinuous portion of the above formed projection data in the slicing direction of the object and forming continuous projection data; and
forming a cardiac tomogram of the object using the continuous projection data.
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Accused Products
Abstract
In an X-ray CT apparatus having a multi-slice detector, the retrospective ECG (Electrocardiography) gating imaging is applied to helical scans. Discontinuity of projection data generated in the scans is interpolated using data at a heartbeat time phase in 180-degree opposite relation to reduce motion artifacts. Further, projection data at an arbitrary slicing position and in at arbitrary heartbeat time phase are formed utilizing continuous divided projection data obtained above, and by properly combining or gathering them, a tomogram of whole heart, a three-dimensional image thereof, and further, a three-dimensional cardiac moving image in heartbeat time phases with an arbitrary time interval can be continuously and smoothly created.
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Citations
28 Claims
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1. A method of producing a cardiac tomogram using an X-ray CT apparatus performing helical scans which has multiple columns of X-ray detector in a slicing direction of an object to be examined and using projection data detected by the X-ray detector, comprising the steps of:
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measuring electrocardiographic information of the object; calculating a number of projection data to be divided necessary for reconstruction of a tomogram in each of the helical scan; collecting divided projection data in an identical heartbeat time phase on the basis of the number of projection data to be divided and an electrocardiographic cycle obtained in the step of measuring the electrocardiographic information, and forming projection data necessary for reconstruction of a tomogram; interpolating a discontinuous portion of the above formed projection data in the slicing direction of the object and forming continuous projection data; and forming a cardiac tomogram of the object using the continuous projection data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16)
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15. A cardiac tomograph, being an apparatus having multiple lines of X-ray detector in the slicing direction of the object for forming a cardiac tomogram of the object using projection data obtained by performing helical scans and detected by the X-ray detector, comprising:
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electrocardiographic information measuring means for measuring electrocardiographic information of the object; means for finding a division number of projection data necessary for reconstruction of a tomogram in each scan of the helical scans; projection data forming means for collecting divided projection data at an identical heartbeat time phase on the basis of the projection data division number and an electrocardiographic cycle measured by the electrocardiographic information measuring means and forming projection data necessary for reconstruction of a tomogram; continuous data forming means for forming continuous projection data by interpolating a portion where the above-formed projection data is discontinuous in the slicing direction of the object; image creating means for creating a cardiac tomogram of the object using the continuous projection data; and display means for displaying the above-formed tomogram. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification