Abstract: A technique is provided for minimizing or eliminating motion-related artifacts present in CT images due to the dynamic nature of the imaged tissue or the time-varying concentration of a contrast agent used for imaging. The technique allows for the selection of a region of interest that may encompass a structure of diagnostic interest. For projections acquired by the various rows of detectors in a multi-slice CT imaging system, the portions of the projections attributable to the projection of the region of interest within the detector are averaged for each view angle. The projections containing these averaged values are then combined with the projections which do not encompass the region of interest and the combined projection set may be reconstructed to form a CT image of the dynamic tissue. In addition, a smoothing step may be performed to interpolate projection values around the region of interest to smooth the visual transition to the unaveraged portions of the image.

Abstract: A method for computing volumetric perfusion in a spatially stationary organ using a computed tomography (CT) imaging system includes positioning an area detector such that the area detector encompasses a spatially stationary organ within the field of view of the imaging system for all view angles, operating the CT imaging system in a cine mode to acquire a plurality of projection data representative of the tissue dynamics in the spatially stationary organ, processing the projection data, temporally filtering respective signals from volume elements of the reconstructions of the projection data which are representative of the tissue dynamics and computing the volumetric perfusion in the organ using the temporally filtered signals from volume elements.

Abstract: A method for computing volumetric perfusion in a spatially stationary organ using a computed tomography (CT) imaging system includes positioning an area detector such that the area detector encompasses a spatially stationary organ within the field of view of the imaging system for all view angles, operating the CT imaging system in a cine mode to acquire a plurality of projection data representative of the tissue dynamics in the spatially stationary organ, processing the projection data, and computing the volumetric perfusion in the organ using the reconstructions of the projection data representative of the tissue dynamics.

Abstract: A method for obtaining data includes scanning at least one of a head of a patient and a neck of the patient with a Multi-Energy Computed Tomography (MECT) system to acquire data.

Abstract: A technique is provided for positioning a reconstruction window in a CT cardiac image data set. The technique uses ECG data, either concurrently acquired or derived from statistical data sets in conjunction with the patient's heart rate, to allow the placement of reconstruction windows at a desired cardiac phase of interest as selected by an operator. The technique can be used in combination with information about the motion or position of a cardiac feature to optimally image the cardiac feature, such as the right coronary artery. In addition, the technique allows unacceptable data from a cardiac cycle to be discarded to improve the final image quality. By using the ECG data to position the reconstruction window, phase misregistration artifacts may be minimized.

Abstract: A technique is provided for improving consistency between slabs in a reconstructed CT image. Candidate sectors associated with an image slab are determined. If the sectors contain sufficient information to reconstruct the image slab, the sector which minimizes inconsistency with projection data for adjacent image slabs is selected for reconstruction. If the sectors do not contain sufficient information to reconstruct the slab, sectors are merged together until a merge group contains sufficient information. The merge group which minimizes inconsistency with projection data for adjacent image slabs is selected for image reconstruction. The selected sectors or merge groups are then reconstructed with the resulting image slabs comprising a reconstructed image with improved consistency between image slabs.

Abstract: A method for arranging detector sections for an imaging system that has a field of view that is defined by a rotational axis and imaging geometry is provided. The method includes providing a plurality of detector sections, and arranging the detector sections in an asymmetric arrangement about a central axis of the field of view.

Abstract: A method for volumetric reconstruction of a cyclically moving object using a computed tomography (CT) system includes scanning a cyclically moving object with a CT imaging system including at least one of an area detector and a linear detector to encompass the desired field of view and a rotating gantry to measure projection data during a plurality of cycles of the cyclically moving object. The method also includes dividing a period of the cyclically moving object into a discrete number of phases, identifying an initial set of projection data at a desired phase of a first cycle at a first angle, identifying at least one subsequent set of projection data at the same desired phase of a subsequent cycle at an angle that is different from the first angle, and combining the initial set of projection data with each subsequent set of identified projection data and using a reconstruction algorithm to generate a three-dimensional image.

Abstract: An apparatus and a method of processing a collection of uncorrected radiographs are described with the apparatus comprising an X-ray scatter compensator and a controller. The compensator is configured for iteratively generating a refined value of a normalized estimated X-ray scatter signal corresponding to an uncorrected radiograph of said collection of uncorrected radiographs. The controller is configured to be coupled to the compensator and further configured to subtract said refined value of said normalized estimated X-ray scatter signal from a corresponding normalized total X-ray signal of a respective one of said uncorrected radiographs so as to form a corresponding corrected radiograph.

Abstract: The present invention provides a model and a method and apparatus for utilizing the model to simulate an imaging scenario. The model is mathematically defined by analytical basis objects and/or polygonal basis objects. Preferably, the model is a model of the human heart and thorax. Polygonal basis objects are only used to define structures in the model that experience torsion, such as certain structures in the heart that experience torsion during the cardiac cycle. The manner in which the basis objects comprising the model are transformed by scaling, translation and rotation is defined for each basis object. In the case where a basis object experiences torsion, the rotation of the basis object will change as a function of the length along the axis of the basis object about which rotation is occurring.

Abstract: An x-ray imaging system images an object by transmitting primary signals and includes a collimator placed between detectors of the x-ray imaging system. The collimator reduces respective scatter components of total signals including a primary signal component and a scatter signal component. One of the detectors detects the total signals, the collimator collimates the primary signals of the total signals focally aligned with the collimator and traveling through the one of the detectors, another of the detectors detects the collimated, primary signals. The x-ray imaging system reduces the scatter components of the total signals detected by the one of the detectors based on the detected, collimated signals and the corresponding, detected, total signals. In another aspect, a detector includes regions of reduced absorption.

Abstract: A collimator 100 for use in a radiation imaging system 10, and a method for making such collimators, are provided, wherein the collimator 100 is capable of collimating radiation in two orthogonal planes. The collimator in one embodiment includes a block 101 of radiation absorbing material having a plurality of focally aligned channels 102 extending therethrough; in a second embodiment, the collimator includes first and second collimation 204, 212 sections having a respective first plurality of focally aligned plate sets 201 and a respective second plurality of focally aligned plate sets 203 disposed orthogonally to the first plurality of plate sets. The method for making the collimator includes generating a CAD drawing, generating from the CAD drawing one or more stereo-lithographic files, and using the stereo-lithographic files to control an electro-deposition machining machine which creates the channels in the block.

Abstract: A collimator 100 for use in a radiation imaging system 10, and a method for making such collimators, are provided, wherein the collimator 100 is capable of collimating radiation in two orthogonal planes. The collimator in one embodiment includes a block 101 of radiation absorbing material having a plurality of focally aligned channels 102 extending therethrough; in a second embodiment, the collimator includes first and second collimation 204, 212 sections having a respective first plurality of focally aligned plate sets 201 and a respective second plurality of focally aligned plate sets 203 disposed orthogonally to the first plurality of plate sets. The method for making the collimator includes generating a CAD drawing, generating from the CAD drawing one or more stereo-lithographic files, and using the stereo-lithographic files to control an electro-deposition machining machine which creates the channels in the block.

Abstract: A method and apparatus for use with a computed tomography (CT) system that collects CT radiograph data for every view of the CT gantry so that a data set corresponding to all views of the gantry is available for use in reconstructing an image of a patient's heart and coronary vasculature. For each view of the gantry, the CT radiograph data associated with the view is collected at different instants in time with respect to the period of the cardiac cycle in each revolution of the gantry. Prior to data acquisition, the patient's heart rate is measured and the period of the gantry is set such that data is acquired at a different time with respect to the period of the cardiac cycle for every view of the gantry and for each revolution of the gantry.

Abstract: In predicting failure of an x-ray tube in a computed tomography (CT) system, reference detector elements normally disposed on each end of the detector, receive x-rays directly from the x-ray tube. In accordance with the invention, the output values of the reference detector elements are utilized by a tube condition prediction algorithm to predict a failure in the x-ray tube of the CT system. The tube condition prediction algorithm utilizes at least one model of the CT system and at least one prediction routine, which typically is a Kalman filter, to generate the prediction. The prediction routine uses the model to analyze the output values of the reference detector elements in order to determine the condition of the x-ray tube and predict future performance of the x-ray tube.

Abstract: A method and apparatus for use with a volumetric computed tomography (CT) scanning system. In accordance with the present invention, the volumetric CT scanning system utilizes an area detector to acquire projection data. The acquired projection data is stored in memory. The projection data corresponding to groups of pixels of the detector is then rebinned to thereby reduce the amount of projection data that will be utilized in performing an initial volumetric reconstruction of the image. The reconstructed image may then be processed to identify particular regions of interest, such as a pathology. If a particular region of interest is identified, all of the projection data corresponding to the region is then used to retrospectively reconstruct a high resolution image of the region of interest. The retrospectively reconstructed high resolution image can then be processed and analyzed to further evaluate the region of interest.

Abstract: A method and apparatus are provided which utilize a circular tomosynthesis system to collect 2-D x-ray projection radiograph data of an object being evaluated. The collected data is then transformed into a form suitable for cone beam volumetric computed tomography (cone beam VCT) reconstruction. Once the data has been transformed, a cone beam VCT reconstruction algorithm may be utilized to reconstruct a 3-D image of the object.

Abstract: A system is provided for identifying faults in a non-OEM computed tomography system having components in connection with the detectors to reconstruct an image. Then, correlation values are derived from baseline reference data files and current data files collected after a fault is suspected in the CT system. The correlation values are compared against a threshold to identify suspect detectors and a pattern recognition algorithm is applied to determine if the suspect detectors are faulty or if one of the components processing the output signals has failed. If baseline files are unavailable, the identification of faulty components is accomplished by performing correlation between the current data files and average profile values.

Abstract: A collimator 100 for use in a radiation imaging system 10, and a method for making such collimators, are provided, wherein the collimator 100 is capable of collimating radiation in two orthogonal planes. The collimator in one embodiment includes a block 101 of radiation absorbing material having a plurality of focally aligned channels 102 extending therethrough; in a second embodiment, the collimator includes first and second collimation204, 212 sections having a respective first plurality of focally aligned plate sets 201 and a respective second plurality of focally aligned plate sets 203 disposed orthogonally to the first plurality of plate sets. The method for making the collimator includes generating a CAD drawing, generating from the CAD drawing one or more stereo-lithographic files, and using the stereo-lithographic files to control an electro-deposition machining machine which creates the channels in the block.

Abstract: The present invention, in one form, is a system for reducing contribution of scatter signal to an image of an object constructed from projection data acquired during a computed tomography scan. The system includes an x-ray source which emits an x-ray beam toward a detector array. A collimator plate is movable with respect to the detector array. The system is configured to move the collimator between a first position and a second position. In the first and second positions, the collimator does not cover the detector array, i.e., the collimator does not collimate the x-ray beam impacting the detector array. When moving between the first and second positions, the collimator at least partially covers the detector array, i.e., the collimator at least partially collimates the x-ray beam impacting the detector array.