Abstract: The present invention, in one form, is an imaging system for generating images of an entire heart. In one embodiment, projection data is collected for a field of view containing only the heart so that the total detector size is reduced. The smaller detector allows the use of a plurality of source-detector pairs so that projection data for an angular coverage of (&pgr;+fan angle) is collected by rotating a gantry significantly less than one complete rotation. Therefore, projection data is collected in significantly less than one cardiac cycle, minimizing motion artifacts.

Abstract: One aspect of the present invention is a method for imaging a volume of a patient with a computed tomographic (CT) imaging system. The method includes steps of: scanning a volume of a patient with a first, full field of view (FOV) scan to acquire first projection data; scanning a smaller volume of the patient with a second, restricted FOV scan to acquire second projection data; estimating an amount of shift between the first projection data and the second projection data resulting from patient movement; and blending first projection data with second projection data in accordance with the estimated amount of shift to estimate projections of the second scan.

Abstract: There is therefore provided, in one embodiment of the present invention, a method for reconstructing a volume image of an object. The method includes steps of scanning an object with a multislice computed tomographic (CT) imaging system having a multislice detector array to acquire projection data of a volume of the object; filtering the acquired projection data; and backprojecting the filtered projection data to reconstruct voxels of the volume image. The multislice detector array has a plurality of rows and columns of detector elements and the backprojecting includes interpolating the filtered projection data across both rows and columns of the multislice detector array.

Abstract: One embodiment is a method for reconstructing at least one image representative of an object utilizing a scanning imaging system having a multislice detector array and a radiation source. The method includes helically scanning the object with the scanning imaging system to acquire a plurality of projection views of the object, including projection views acquired at different cone angles of the radiation beam; selecting a region of reconstruction (ROR) to define sets of conjugate samples in the projection views; and reconstructing at least one image of the object. The reconstruction includes weighting the sets of conjugate samples using a cone-angle dependent weighting function, and filtering and backprojecting the weighted samples.

Abstract: A method for generating an image of an object using a computed tomography (CT) imaging system, which includes at least one x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, includes the steps of identifying a physiological cycle of the object (the cycle comprising a plurality of phases); selecting at least one phase of the object; collecting at least one segment of projection data for each selected phase of the object during each rotation of each x-ray source; generating a projection data set by combining the projection data segments; generating a cross-sectional image of the entire object from the projection data set; and communicating the image or data associated with the image to a remote facility. The remote facility provides remote services over a network.

Abstract: A method for weighting projection data is provided. The method includes helically twin beam scanning an object at a selected pitch to acquire a first data sample from a first detector row and a second data sample from a second detector row. The first data sample includes first conjugate data and first two pi data. The second data sample includes second conjugate data and second two pi data. The first conjugate data and the second conjugate data are conjugate each other, and the first two pi data and the second two pi data are two &pgr; projection angle apart. The method also includes identifying a center view of the first conjugate data and the second conjugate data, and weighting at least one of the first conjugate data, the second conjugate data, the first two pi data, and the second two pi data inverse to the identified center view.

Abstract: The present invention, in one form, is a method for generating depth information images of an object using a computed tomography system by performing multiple scout scans of the object, generating a scout image for each scout scan, and displaying the scout images from each scout scan at least once. As a result, the multiple scout images contain depth information of anatomical objects and 3D images are rapidly generated without increasing the cost of the system.

Abstract: A method and apparatus for configuring a large CT detector using a plurality of smaller X-ray type detector panels wherein the panels are sized and arranged in side by side fashion to extend across a fan beam and so that where conjugate rays generated during acquisition always include at least one ray that subtends a detector panel and generates a collected signal even where the other ray in the conjugate pair is directed at a gap between panels, the method further including, after data is acquired, interpolating across each gap and then combining the interpolated data across the gaps with the collected signals to generate back projection data for each of the gap directed rays.

Abstract: In one embodiment, the present invention is a method for reducing radiation dosage when scanning an region of interest of an object with a multi-slice computed tomography (CT) imaging system. The method includes steps of collimating the radiation beam of the CT imaging system into a fan-shaped radiation beam having at least a first region and a second region, the first region having a lesser angular extent than that of the second region; scanning an object having a region of interest (ROI) with the collimated radiation beam- and reconstructing an image of the object using the attenuation measurements collected during the scan, wherein the reconstruction utilizes attenuation measurements collected using the second region of the radiation beam to estimate projection data from portions of the object outside of the ROI blocked by the collimation.

Abstract: One embodiment of the present invention is a method for generating an image of an object using a multislice computed tomography imaging system. The method includes steps of: helically scanning an object with a multislice computed tomography imaging system to acquire projection data; determining a set of conjugate samples of the projection data that formulate a set of parallel projections; and reconstructing a set of images of the object using the conjugate samples. By determining a set of conjugate samples that formulate a set of parallel projections, embodiments of the present invention make possible reconstruction of images from projection data scanned at 8:1 pitch or higher.

Abstract: Methods and apparatus for generating a difference image to determine perfusion parameters, such as mean transit time, cerebral blood flow, and cerebral blood volume utilizing a CT imaging system are described. To generate difference images, a difference projection data set including a first sub-set and a second sub-set of projection data is acquired. The first sub-set is obtained when no contrast medium is present in a patient or shortly after the contrast medium is injected into the patient. The second sub-set is obtained after the contrast medium is absorbed by the patient. The difference projection data is generated by subtracting the first sub-set from the second sub-set. The difference projection data then undergoes image reconstruction processing to generate the difference images. The difference images are then mapped to an image generated using the first sub-set, and perfusion parameters are determined utilizing the mapped difference image.

Abstract: The present invention, in one form is an imaging system for generating images of an entire object. In one embodiment, a physiological cycle unit is used to determine the cycle of the moving object. By altering the rotational speed of an x-ray source as a function of the object cycle, segments of projection data are collected for each selected phase of the object during each rotation. After completing a plurality of rotations, the segments of projection data are combined and a cross-sectional image of the selected phase of the object is generated. As a result, minimizing motion artifacts.

Abstract: A method for reducing slice thickness of a computed tomography imaging system including a source configured to direct an x-ray beam through an object toward a plurality of rows of detector elements configured to collect projection data in slices. The method includes steps of obtaining imaging data from a pair of adjacent rows, each of the adjacent rows having an outer edge; deconvolving at least a portion of the imaging data obtained from an area bounded by the adjacent row outer edges; and combining the deconvolved imaging data to obtain a slice sensitivity profile for the adjacent row pair. This method allows a multi-slice imaging system user to implement imaging data deconvolution to reduce slice thickness to less than one millimeter. Thus image resolution is improved without having to modify hardware in existing multi-slice imaging systems.

Abstract: Methods and Apparatus for reducing image artifacts when reconstructing an image with a multislice computed tomographic (CT) imaging scanner are provided. Scout images are generated by obtaining a plurality of projection views of an object, modifying the projection data utilizing a deconvolution kernel, generating a horizontal gradient and a vertical gradient based on the modified projection data, applying helical weights to the horizontal gradient and vertical gradient, and applying a desired level of enhancement to the weighted horizontal and vertical gradients.

Abstract: The present invention, in one form, is an imaging system for generating images of an entire object. In one embodiment, a physiological cycle unit is used to determine the cycle of the moving object. By altering the rotational speed of an x-ray source as a function of the object cycle, segments of projection data are collected for each selected phase of the object during each rotation. After completing a plurality of rotations, the segments of projection data are combined and a cross-sectional image of the selected phase of the object is generated. As a result, minimizing motion artifacts.

Abstract: Helical acquisition of thin computed tomography slices by collimation of the fan beam to less than the width of a multi-row detector is provided by interpolation after application of the weighting scheme correcting for asymmetry in the detector profile of the detectors with such collimation.

Abstract: In one aspect, the present invention is a method for filtering projection data of a computed tomographic scan of an object. The method includes steps of: acquiring projection data representing a tilted, helical scan of an object; zero padding the acquired projection data; determining a Fourier transform of the zero padded projection data; determining a product of the Fourier transform of the zero padded projection data, a ramp function, and a phase shift function; and determining an inverse Fourier transform of the multiplied, transformed projection data as filtered projection data. The above-described method provides filtered data that produces compensated tilted, helically scanned CT images having significantly better spatial resolution than those methods employing a high frequency kernel boost.

Abstract: One aspect of the present invention is a method for computerized tomographic (CT) imaging of an object. One embodiment of the method includes scanning an object with a CT imaging system to acquire views that include projection samples of an object; interpolating the acquired views within a selected view range to produce interpolated views; weighting the interpolated views to compensate for the interpolation; weighting the acquired views; and filtering and backprojecting the weighted, interpolated views and the weighted acquired views to generate an image of the object. View aliasing artifacts are reduced by this embodiment without using conjugate samples.

Abstract: Methods and corresponding apparatus for imaging a portion of a patient's body with a computed tomographic imaging system configured to scan the patient's body at a cyclically varying view angle, in which the imaging system includes a radiation source and detector array providing a fan angle width of image data. In one embodiment, the method includes axially scanning the portion of the patient's body, gating the radiation source on over less than a 360 °view angle cycle of the axial scan, acquiring image data of the portion of the patient's body during at least a portion of the time the radiation source is gated on, and assembling the acquired image data into an image of the portion of the patient's body.

Abstract: A method for producing a base tomographic image and a subsequent tomographic image of an object using projection data acquired in a scan with a system which includes an x-ray source and a detector array which includes a plurality of detectors. The method includes applying a segmentation algorithm to the projection data to generate base image data comprising a plurality of segments; generating image data for each segment; generate subsequent image data based on image data of each segment; and communicating image data, segments, subsequent image data, or base image data to a remote facility via a network. The remote facility provides remote services.