Image Processing (5) Flashcards
Processing (2)
“Reconstruction”
The process by which raw attenuation numbers are converted to viewable image data
Scan Data (3)
“Unprocessed Data”
Raw data leaving DAS which can’t be viewed by tech
Stored only in CT control console
Image Data (2)
“Processed Data”
Data sent to PACS
Steps of Reconstruction (3)
Interpolation
Convolution
Filtered Backprojection
Interpolation (2)
Estimating the unknown numeric value within a set of known values
e.g. if A=1, B=2, D=4 then C~3
Required by helical scanners in order to convert spiral into axial pics
Convolution
Mathematic filtering of data to better visualize specific tissues; adjusting each pixel to desired level of edge enhancement (sharpness)
E.g. Bone vs Standard
Mathematical Filters used for Convolution (3)
Algorithms, Filters, Kernels
Edge-enhancing algorithm
Bone algorithm
Backprojection (2)
Process by which all projections are superimposed back onto each other to form the image matrix
Each view is smeared across the image slice
“Filtered” Backprojection
(Filtering) removes blurring artifact typical of unfiltered BP
Iterative Reconstruction is an enhancement of FBP resulting in (2)
Lower patient dose
Improved image quality
Standard Kernels add _______ to the image and are useful in viewing _______ _______.
Smoothness
Soft Tissues
Thicker slices allow (3):
Decreased dose
Decreased image noise
Fewer total slices
Smaller parts such as _______ _______ & _______ should be imaged with thinner slices
Blood Vessels
Bones
Reconstruction Slice Interval
Space from one image to the next
Distance between adjacent slices
