How do you reconstruct a CT image?
CT makes use of filtered back projection reconstruction techniques, whereby each projection is convolved with a “filter”, and then back projected. When this procedure is performed for all 1000 or so projections, it is possible to achieve a perfect reconstruction of the scanned object.
What is the typical reconstruction matrix of a CT image?
The reconstruction matrix is the array of rows and columns of pixels in the reconstructed image. The display matrix is the matrix in the displayed image and can be equal to or larger than the reconstruction matrix size due to interpolation procedures.
What is CT 3D reconstruction?
Three dimensional CT (3D CT) is essentially a method of surface rendition of anatomy by means of a special computer software. The software is available in modern CT scanners as an optional package, or may be available as an auxiliary unit to be used in tandem with an existing scanner .
What is the difference between SFOV and DFOV?
DFOV: Display field of view– determines how much of the scan field of view is reconstructed into an image. DFOV can be less than or equal to the SFOV but cannot be more than the SFOV. High contrast resolution: The ability to distinguish sharp edges between small objects that differ greatly in density.
What is FBP reconstruction?
Filtered back projection is an analytic reconstruction algorithm designed to overcome the limitations of conventional back projection; it applies a convolution filter to remove blurring. It was, up until recently the primary method in cross-sectional imaging reconstruction.
Which of the following reconstruction methods is used by most modern CT scanners?
The most commonly used analytical reconstruction methods on commercial CT scanners are all in the form of filtered backprojection (FBP), which uses a 1D filter on the projection data before backprojecting (2D or 3D) the data onto the image space.
What are the types of image reconstruction in CT?
What is sinogram in CT?
A sinogram is a special x-ray procedure that is done to visualize any abnormal opening (sinus) in the body, following the injection of contrast media (x-ray dye) into the opening.
Can CT scans produce 3-D images?
CT (Computed Tomography) Scan. Computed tomography (CT) scan is a useful diagnostic tool for detecting diseases and injuries. It uses a series of X-rays and a computer to produce a 3D image of soft tissues and bones. CT is a painless, noninvasive way for your healthcare provider to diagnose conditions.
What is matrix in CT?
“A CT image is composed of a square image matrix that ranges in size from 256 X 256 to 1024 X 1024 picture elements or pixels. Since a CT section has a finite thickness, each pixel actually represents a small volume element, or voxel.
How is DFOV calculated in CT?
The formula for DFOV is pixel dimension x the matrix size. 320 x . 75 mm = 240mm or 24 cm DFOV.
What is filtered backprojection FBP algorithm used for?
The filtered backprojection (FBP) algorithm is simple and fast, and can be used to reconstruct images in nuclear medicine and x-ray CT.
What does the RAM Lak filter do?
Ram-Lak and Shepp-Logan filters are high pass filters which keeps the edges information in tact, whereas cosine, hamming and hann filters are band pass filters. They are used to smooth the image and remove extra edges from the …
What are MIP images?
Abstract. Maximum intensity projection (MIP) is a simple three-dimensional visualization tool that can be used to display computed tomographic angiography data sets. MIP images are not threshold dependent and preserve attenuation information.
What is a Scanogram used for?
Supine computed tomography scanogram (CTS) is a commonly used alternative to weight bearing long leg plain radiograph (LLR) in measuring knee alignment.