- Protocols for Multislice CT - 4- and row Applications | Roland Bruening | Springer;
- Technology Insight: cardiac CT angiography!
The protocol may designate a head trauma study and may comprise instructions for acquiring axial scan data sets; preprocessing raw scan data; reconstructing sets of cross-sectional images with different slice thickness for different portions of the head; and displaying the image sets simultaneously. The protocol may designate an axial image display mode, weighting multiple ultra thin slice cross sectional images, and generating an image with a desired slice thickness. According to a second aspect of the invention, there is provided a multislice imaging system programmed to execute a scan in accordance with a protocol, said protocol comprising designations for at least one of slice thickness, image reconstruction filter, display method, filming requirement and image archiving requirement.
The system may be further programmed to perform a scan in accordance with a predefined protocol designating at least one of slice thickness, image reconstruction filter, display method, filming requirement and image archiving requirement. The protocol may designate a head trauma study and may comprise instructions for: acquiring axial scan data sets; preprocessing raw scan data; reconstructing sets of cross-sectional images with different slice thickness for different portions of the head; and displaying the image sets simultaneously. The protocol designates an axial image display mode, weighting multiple ultra thin slice cross sectional images, and generating an image with a desired slice thickness.
Thus the invention can provide a scalable multislice system configured to generate multiple streams of image data with different image quality characteristics prospectively and simultaneously. For example, in the axial multi-slice scan mode, multiple rows of scan data can be processed before image reconstruction, and are used to produce either a multiple thin slices for maximum z-axis resolution or b reduced number of thicker image slices with reduced image artifacts in comparison to conventional CT scanners.
As described below in detail, in a data acquisition mode of 4x2. The 2. The 10mm images provide reduced partial volume artifact compared with a single slice CT 10 mm slice. In helical multi-slice scanning, multi-slice helical image reconstruction algorithms enable generation of multiple image sets having different z-axis resolution, both prospectively and retrospectively.
MDCT: How Many Rows Is Enough?
Accordingly, multiple protocols are "pre-built" based on specific applications to determine image slice thickness, image reconstruction filter, display field of view, filming requirement and image archiving requirement, prospectively. A protocol specific for CTA can be defined as follows.
The above described image reconstruction and display methods and apparatus facilitate improving imaging productivity, reducing the number of CT scans, and decreasing diagnosis cycle time. Such methods and apparatus may also reduce the number of unwanted images for viewing, filming and archiving, and have the capability of producing 3- or 4-dimensional images with high z-axis resolution information for multiple clinical purposes.
The invention will now be described in greater detail, by way of example, with reference to the drawings, in which Figure 2 is a block schematic diagram of the system illustrated in Figure 1. Figure 3 is an exemplary embodiment of a scan user interface than can be used in conjunction with the system illustrated in Figures 1 and 2. Figure 4 is a logic diagram of protocol driven image reconstruction, display, analysis, and archiving.
The present invention is directed, in one aspect, to protocol driven image reconstruction, display and archiving, and in another aspect to a method for multislice image generation. The invention can be practiced in connection with many different types of imaging systems, and is not limited to practice to any one type of system. Set forth herein, however, is a detailed description of an exemplary multislice CT system, and although such CT system is described in detail below, it should be understood that the present invention is not limited to practice with such system.
More particularly, and referring to Figure 1, an exemplary computed tomography CT imaging system 10 in accordance with one embodiment of the present invention is shown as including a gantry 12 representative of a "third generation" CT scanner. Gantry 12 has an x-ray source 14 that projects a beam of x-rays toward a detector array 16 on the opposite side of gantry Detector array 16 is formed by a plurality of detector modules which together sense the projected x-rays that pass through a medical patient Each detector module produces an electrical signal that represents the intensity of an impinging x-ray beam and hence the attenuation of the beam as it passes through patient During a scan to acquire x-ray projection data, gantry 12 and the components mounted thereon rotate about a center of rotation.
MDCT protocols boil down to tradeoffs
A motorized table 20 positions patient 18 relative to gantry Particularly, table 20 moves portions of patient 18 through a gantry opening 22 during a scan. As shown in Figure 2, system 10 includes a host computer 24 coupled to a monitor user interface 26 for displaying images and messages to an operator. Computer 24 also is coupled to a keyboard 28 and a mouse 30 to enable the operator to input information and commands to computer Computer 24 is coupled to a scan and reconstruction control unit SRU SRU 32 also includes image generation controls.
SRU 32 also includes an interface processor for interfacing with the data acquisition system described below , and a scan data correction digital signal processing board for performing preprocessing, which is known in the art. SRU 32 further includes an image generator for filtered backprojection and postprocessing operations, as is known in the art. A stationary controller 34 is connected to SRU 32, and controller 34 is coupled to a table controller Stationary controller 34 also is connected, through a slipring 38, to an on-board controller 40 and a scalable data acquisition system SDAS Slipring 38 enables contactless transmission of signals across the slipring boundary and supports the necessary bandwidth for transmission of data and commands across the boundary.
SDAS 42 samples and acquires the data from detector 16 and converts the sampled analog signals to digital signals. SDAS 42, in one specific embodiment, includes forty eight interchangeable converter cards to support four row data acquisition.
For two row data acquisition, twenty four cards could be used. In one specific embodiment, there are sixty four input channels per converter card and Hz sampling can be performed. SDAS 42 also includes a front-end pre-amplifier for amplifying the signals. Further details regarding SDAS are set forth below. On-board controller 40 controls operation of x-ray source 14 and operation of SDAS X-ray source 14 includes a high voltage generator 44 coupled to an x-ray tube Tube 46 may, for example, be the tube known in the art is the Gemini-1 tube and currently utilized in at least some CT system commercially available from General Electric Company, Milwaukee, WI, Beams projected by X-ray tube 46 pass through a prepatient cam collimator 48 and impinge upon detector 16 illustrated as a 16 row detector.
Cam collimator 48 also is controlled by on-board controller Outputs from detector 16 are supplied to SDAS In Figure 2, data flow is illustrated by bold lines, control flow is illustrated by normal lines, and real-time control flow is illustrated by dotted lines. The numeric identifiers associated with the flows are set forth below. Computer 24 also receives commands and scanning parameters from an operator via keyboard 28 and mouse Monitor 26 allows the operator to observe the reconstructed image and other data from computer The operator supplied commands and parameters are used by computer 24 to provide control signals and information.
In addition, controller 36 controls motorized table 20 to position patient 18 Figure 1. Generally, the above described CT system is operable to collect 1, 2 or more slices data. Scalable axial image reconstruction and display refers, for example, to selectability of the image thickness, number of slices, and number of images to be displayed. Further, the system is not limited to practice with any one particular image reconstruction algorithm, and it is contemplated that many different reconstruction algorithms can be utilized. Exemplary algorithms are set forth in U. Patent Nos.
Patent Application Serial Nos. In the axial multi-slice scan mode, multiple rows of scan data can be processed before image reconstruction, and the data can be used to produce either multiple thin slices or a reduced number of thicker slices with reduced image artifact. In addition, images with thicker slice thicknesses can be later reconstructed retrospectively into thinner slices of images based on clinical diagnosis needs. As a result, the number of unwanted images for viewing, filming, and archiving is reduced. The high speed of the scan requires up-to-date and careful protocol optimization.
Scanner technology and geometry affect image formation procedure and imaging protocols should be adapted accordingly.
The technical foundations of spiral CT imaging and the main scan and reconstruction parameters are described in this article. Updated protocols and clinical examples of the latest applications are also discussed. National Center for Biotechnology Information , U. Didn't get the message? Find out why Published in: Business. Full Name Comment goes here. Are you sure you want to Yes No. Be the first to like this. No Downloads. Views Total views. Actions Shares. Embeds 0 No embeds. No notes for slide.
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