Method and apparatus for reducing artifacts in images reconstructed from image data acquired by a computed tomography system

Claim 1

A computed tomography (CT) system for imaging a patient comprising: a gantry comprising an x-ray tube and a detector array, the x-ray tube generating x-rays, the detector array receiving x-rays emitted by the x-ray tube, the detector array comprising a plurality of detector elements, each detector element generating an output signal in response to x-rays impinging thereon; a support surface adapted to receive and support a patient; a controller component in communication with the gantry, the controller component being capable of producing relative rotational motion between the x-ray tube and the detector array about the support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry, the patient having a heart rate, the heart rate being associated with a cardiac cycle, the cardiac cycle having a period; a data acquisition component in communication with the detector array, the data acquisition component being capable of sampling the detector elements by reading and digitizing the output signals generated by the detector elements; and a computer in communication with the controller component and with the data acquisition component, the computer causing the data acquisition component to sample the detector elements at least once for each view of the gantry, wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry.

Claim 13

A method for acquiring radiograph data in a computed tomography (CT) system, the CT system comprising a gantry, the gantry comprising an x-ray tube and a detector array, the x-ray tube generating x-rays, the detector array receiving x-rays emitted by the x-ray tube, the detector array comprising a plurality of detector elements, each detector element generating an output signal in response to x-rays impinging thereon, the method comprising the steps of: measuring a heart rate of a patient, the heart rate being associated with a cardiac cycle, the cardiac cycle having a period; producing relative rotational motion between the x-ray tube and the detector array about a support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry; and sampling the detector elements by reading and digitizing the output signals generated by the detector elements, the detector elements being sampled at least once for each view of the gantry, and wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry.

Claim 14

A method for acquiring radiograph data in a computed tomography (CT) system, the CT system comprising a gantry, the gantry comprising an x-ray tube and a detector array, the x-ray tube generating x-rays, the detector array receiving x-rays emitted by the x-ray tube, the detector array comprising a plurality of detector elements, each detector element generating an output signal in response to x-rays impinging thereon, the method comprising the steps of: measuring a heart rate of a patient, the heart rate being associated with a cardiac cycle, the cardiac cycle having a period; producing relative rotational motion between the x-ray tube and the detector array about a support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry; and sampling the detector elements by reading and digitizing the output signals generated by the detector elements, the detector elements being sampled at least once for each view of the gantry, and wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry.

Claim 15

A method for reducing artifacts in images reconstructed from image data acquired by a computed tomography (CT) system, the method comprising the steps of: measuring a heart rate of a patient, the heart rate being associated with a cardiac cycle, the cardiac cycle having a period; producing relative rotational motion between the x-ray tube and the detector array about a support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry, wherein the revolutions of the gantry occur at a rotational rate that is greater than or less than the measured heart rate of the patient; and sampling the detector elements by reading and digitizing the output signals generated by the detector elements, the detector elements being sampled at least once for each view of the gantry, and wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry; monitoring the heart rate of the patient with an electrocardiogram (ECG) monitoring device, the ECG monitoring device producing an ECG waveform corresponding to the cardiac cycle of the patient; obtaining digital samples of the ECG waveform from the ECG monitoring device simultaneously as the detector elements are sampled; storing the detector element samples and the ECG waveform samples at locations in a memory device such that each detector element sample is associated in the memory device with a particular ECG waveform sample and with a particular view of the gantry, the detector element samples corresponding to radiograph data; reading the radiograph data and the ECG waveform samples out of the memory device and, for each view of the gantry, correlating the radiograph data associated with the view with the ECG waveform samples associated with the radiograph data; processing the correlated radiograph data to interpolate radiograph data to a single instant in time with respect to the period of the cardiac cycle; and processing the interpolated radiograph data to reconstruct a 3-D image of the patient's heart at the single instant in time.

Claim 16

A method for reducing artifacts in images reconstructed from image data acquired by a computed tomography (CT) system, the method comprising the steps of: measuring a heart rate of a patient, the heart rate being associated with a cardiac cycle, the cardiac cycle having a period; producing relative rotational motion between the x-ray tube and the detector array about a support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry, wherein the revolutions of the gantry occur at a rotational rate that is greater than or less than the measured heart rate of the patient; and sampling the detector elements by reading and digitizing the output signals generated by the detector elements, the detector elements being sampled at least once for each view of the gantry, and wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry; monitoring the heart rate of the patient with an electrocardiogram (ECG) monitoring device, the ECG monitoring device producing an ECG waveform corresponding to the cardiac cycle of the patient; obtaining digital samples of the ECG waveform from the ECG monitoring device simultaneously as the detector elements are sampled; storing the detector element samples and the ECG waveform samples at locations in a memory device such that each detector element sample is associated in the memory device with a particular ECG waveform sample and with a particular view of the gantry, the detector element samples corresponding to radiograph data; reading the radiograph data and the ECG waveform samples out of the memory device and, for each view of the gantry, correlating the radiograph data associated with the view with the ECG waveform samples associated with the radiograph data; processing the correlated radiograph data to interpolate radiograph data to a single instant in time with respect to the period of the cardiac cycle; and processing the interpolated radiograph data to reconstruct a 3-D image of the patient's heart at the single instant in time.

Claim 27

An apparatus for use in a computed tomography (CT) system for acquiring radiograph data to be used by the CT system, the CT system comprising a gantry, a support table a controller component, and a data acquisition component, the gantry comprising an x-ray tube and a detector array, the x-ray tube generating x-rays, the detector array receiving x-rays emitted by the x-ray tube, the detector array comprising a plurality of detector elements, each detector element generating an output signal in response to x-rays impinging thereon, the support surface being adapted to receive and support a patient, the controller component being in communication with the gantry and being capable of producing relative rotational motion between the x-ray tube and the detector array about the support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry, the patient having a heart rate associated with a cardiac cycle, the cardiac cycle having a period, the data acquisition component being in communication with the detector array and being capable of sampling the detector elements by reading and digitizing the output signals generated by the detector elements, the apparatus comprising: a computer in communication with the controller component and with the data acquisition component, the computer causing the data acquisition component to sample the detector elements at least once for each view of the gantry, wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry.

Claim 28

An apparatus for use in a computed tomography (CT) system for acquiring radiograph data to be used by the CT system, the CT system comprising a gantry, a support table a controller component, and a data acquisition component, the gantry comprising an x-ray tube and a detector array, the x-ray tube generating x-rays, the detector array receiving x-rays emitted by the x-ray tube, the detector array comprising a plurality of detector elements, each detector element generating an output signal in response to x-rays impinging thereon, the support surface being adapted to receive and support a patient, the controller component being in communication with the gantry and being capable of producing relative rotational motion between the x-ray tube and the detector array about the support surface, wherein 360° of relative rotational motion corresponds to a revolution of the gantry, each revolution of the gantry corresponding to a plurality of views of the gantry, the patient having a heart rate associated with a cardiac cycle, the cardiac cycle having a period, the data acquisition component being in communication with the detector array and being capable of sampling the detector elements by reading and digitizing the output signals generated by the detector elements, the apparatus comprising: a computer in communication with the controller component and with the data acquisition component, the computer causing the data acquisition component to sample the detector elements at least once for each view of the gantry, wherein for each revolution of the gantry, each detector element is sampled at a different instant in time with respect to the period of the cardiac cycle for each view of the gantry.

Claim 34

An apparatus for reducing artifacts in images reconstructed from image data acquired by a computed tomography (CT) system, the apparatus comprising: a computer, the computer obtaining detector element samples and ECG waveform samples from address locations in a memory device, the detector element samples corresponding to radiograph data, the computer correlating the radiograph data with the samples of the ECG waveform for each view of a gantry of a CT system, the computer performing an interpolation algorithm that processes the correlated radiograph data to interpolate radiograph data to a single instant in time with respect to the period of the cardiac cycle, the computer processing the interpolated detector element samples to reconstruct an image of the patient's heart at the single instant in time.

Claim 35

An apparatus for reducing artifacts in images reconstructed from image data acquired by a computed tomography (CT) system, the apparatus comprising: a computer, the computer obtaining detector element samples and ECG waveform samples from address locations in a memory device, the detector element samples corresponding to radiograph data, the computer correlating the radiograph data with the samples of the ECG waveform for each view of a gantry of a CT system, the computer performing an interpolation algorithm that processes the correlated radiograph data to interpolate radiograph data to a single instant in time with respect to the period of the cardiac cycle, the computer processing the interpolated detector element samples to reconstruct an image of the patient's heart at the single instant in time.