The algorithm enables us to achieve acceptable image quality and spatial resolution at a scanning speed that is about three times faster than that for single-slice CT. The new algorithm allows suitable combinations of scan and filter parameters to be selected to meet the purpose of each examination.
Also question is, what is CT algorithm?
The reconstruction kernel, also referred to as “filter” or “algorithm” by some CT vendors, is one of the most important parameters that affect the image quality. A smoother kernel generates images with lower noise but with reduced spatial resolution.
Similarly, what is bone algorithm? High-spatial-frequency (bone) algorithm improves quality of standard CT of the thorax. The definition of mediastinal contents with the bone algorithm was judged equal or superior to the standard algorithm in 94% of images (p less than . 001).
Beside this, what is kernel in CT scan?
The kernel, or convolution algorithm, refers to the process used to modify the frequency contents of projection data prior to backprojection 1. This process corrects the image by reducing blurring 1. The kernel affects the appearance of image structures by sharpening the image.
What is tomographic imaging?
Tomography is imaging by sections or sectioning, through the use of any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, quantum information, and other areas of science.
What is back projection algorithm?
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 is achieved via an algorithm of 250,000 mathematical equations that can be solved by a high capacity computer.
How do you reconstruct a CT image?
The standard method of reconstructing CT slices is backprojection. This involves "smearing back" the projection across the image at the angle it was acquired. By smearing back all of the projections, you reconstruct an image.
What is iterative reconstruction in CT?
Iterative reconstruction (CT) Dr Daniel J Bell ? and Andrew Murphy ? et al. Iterative reconstruction refers to an image reconstruction algorithm used in CT that begins with an image assumption, and compares it to real time measured values while making constant adjustments until the two are in agreement.
What is pitch in CT?
(p) The pitch (in computed tomography) is the ratio of the patient table increment to the total nominal beam width for the CT scan. The pitch factor relates the volume coverage speed to the thinnest sections that can be reconstructed. Pitch = table movement per rotation/slice collimation.
What is an algorithm in radiography?
Algorithm. An algorithm is a computer compatible equation. Computed tomographic algorithms reconstruct a function from its projections. A very large number of measurements are processed with complex mathematical operations to compute cross-sectional images.
What is scan field of view in CT?
(FOV) The field of view is the maximum diameter of the area of the scanned object that is represented in the reconstructed image. (SFOV) The scan field of view is the area being scanned. This selectable scan factor is measured from a CT system isocenter to the most distant located edge of the patient.
What is 3d rendering in radiology?
In scientific visualization and computer graphics, volume rendering is a set of techniques used to display a 2D projection of a 3D discretely sampled data set, typically a 3D scalar field. A typical 3D data set is a group of 2D slice images acquired by a CT, MRI, or MicroCT scanner.
What is CT slice thickness?
Slice thickness and slice increment are central concepts that surround CT/MRI imaging. Slice thickness refers to the (often axial) resolution of the scan (2 mm in the illustration). Slice Increment refers to the movement of the table/scanner for scanning the next slice (varying from 1 mm to 4 mm in the illustration).
What is a 64 slice CT scanner?
64-Slice CT Scan. Like a traditional computed tomography (CT) scan, our 64-slice CT scan combines a series of X-ray views taken from many different angles, and then uses a computer to reconstruct the “slices” to produce actual pictures.
How is CT pitch calculated?
Single slice CT (SSCT)
The term detector pitch is used and is defined as table distance traveled in one 360° gantry rotation divided by beam collimation 2. For example, if the table traveled 5 mm in one rotation and the beam collimation was 5 mm then pitch equals 5 mm / 5 mm = 1.0.What is section width in CT?
The initial CT examination is usually performed with a thick section width (8–10 mm) to minimize scanning time and thus allow imaging of the entire chest during a single breath hold.
What is interpolation in CT?
Interpolation is a mathematical process used to smooth, enlarge or average images that are being displayed with more pixels than that for which they were originally reconstructed. Usually, magnification is the enlargement of an area by interpolation after the reconstruction of an image.
What is table increment in CT?
Couch Increment. The couch increment is the distance by which the position of a patient table is changed between individual slices. In spiral CT scanning the couch increment is the change of the table position during one 360° rotation of the x-ray tube.
What is helical CT?
Helical CAT scan: Helical computed axial tomography scan (CAT scan or CT scan) is another name for a CT scan, and is also called a spiral CT scan. Helical or spiral CT scans are obtained usually with one breath hold and obtain a volume of X-rayed tissue while the table moves rapidly through the gantry.
What is retrospective reconstruction in CT?
Retrospective image reconstruction is also known as CT reconstruction because CT stands for Computed Tomography. Tomographic reconstruction refers to the amount of projections needed for a certain system. In regard to the retrospective image reconstruction, slice thickness and SFOV may not be changed.
What is helical pitch?
Helical pitch is a measure of the vertical distance (relative to the helical axis) separating two points on a helix after one complete "turn" (spanning 2pi radians) [1]. The pitch of a typical 3.6-helix (an alpha helix with 3.6 residues per "turn") is approximately 5.4 angstroms [2].
What color will brain tissue appear on a CT scan?
Water (in the cerebral ventricles or fluid-filled cavities in the middle of the brain) absorbs little, and appears black. The brain has intermediate density and appears grey. Most ischemic strokes are less dense (darker) than normal brain, whereas blood in hemorrhage is denser and looks white on CT.
