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CT is superior to all other clinical modalities in:
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An alternative name for contrast resolution
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ct image review
ct image review- last unit
| Question | Answer |
|---|---|
| CT is superior to all other clinical modalities in: | Contrast resolution |
| An alternative name for contrast resolution | Low contrast resolution |
| Which of the following has the longest gray scale of contrast? WW 3000 WL 500 WW 100 WL 40 WW 1000 WL -500 WW 500 WL 0 | WW 3000 WL 500 |
| Which of the following would have the shortest gray scale contrast ? WW 3000 WL 500 WW 100 WL 0 WW 1000 WL -500 WW 500 WL 0 | WW 100 WL 0 |
| Which of the following best describes a fluxuation of CT number within a uniform material? | Noise |
| Which of the following would reduce contrast resolution? | Increasing matrix size |
| Which of the following parameters does NOT affect image quality? | Dose |
| Which of the following is the ability to discriminate objects a small distance apart? | detail resolution |
| Which of the following HU’s would appear white given a WW 200 & WL 0? | 200 |
| Which of the following HU numbers is most accurate? HU: 4 Std:20 HU 2000 Std: 1 HU 40 Std: 10 HU 5 Std: 5 | HU 2000 STD 1 |
| Which of the following HU’s represents water? | 0 |
| Which of the following HU’s represents air? | -1000 |
| Which of the following HU’s represents bone? | 1000 |
| Which of the following needs raw data to complete? | change DFOV |
| WW 1000 WL 0.. Which change would make a longer gray scale? | change WW to 3000 |
| What type of data is needed for retrospective reconstruction | scan data |
| Which of the following provides the best spatial resolution? | .20 |
| Which of the following matrix sizes would give the best contrast resolution | 256 x 256 |
| What is the CT number related to? | linear attenuation coefficient |
| This type of data is collected from the detectors and sent to the computer for processing (analog or digital is not the answer). | raw or scan |
| What is the process of using raw data to create an image? | image reconstruction |
| What is the name of the area within gantry where data from patient will be collected? | scan FOV |
| What is the area of the data that is displayed for radiologist viewing? | display FOV |
| What type of image rendering process creates images in a different orientation? | multiplanar reconstruction MPR |
| What type of data is needed to perform retrospective reconstruction? | raw |
| What type of image reconstruction allows for optimal image quality at a reduced dose? | iterative reconstruction |
| What is the mathematical process used of estimating values of an unknown by using known values on either side? | interpolation |
| Which of the following would appear white given the WW 2000 and WL 0? 2000 -2000 100 -100 | 2000 |
| What does window level refer to? | Center of the CT numbers; selected number in the area of the types of tissues you want to display |
| What does window width refer to? | The number of shades of gray |
| What HU represents air? | lung tissue -1000 |
| Which of the following will best display bone tissue? Ww 3000 WL 400 WW 2000 WL 50 WW 500 WL 0 WW 3000 WL -1000 | WW 3000 WL 400 |
| Which of the following would shorten the gray scale of an image if you originally used ww 2000, wl 500 Change ww to 1000 Change the ww to 3000 Change the wl to 1000 Change the wl to 100 | change the ww to 1000 |
| What is the HU for water? | 0 |
| What is the HU for bone? | 1000 |
| Which of the following would be the most accurate representation of a tissue? A. HU 0 STD. 100 B. HU 100 STD 23 C. HU -400 STD 10 D. HU 0 STD 50 | HU -400 , STD 10 |
| Which of the following would be the most accurate representation of water? A. HU 0 STD. 100 B. HU 40 STD 23 C. HU -100 STD 0 D. HU 0 STD 5 | HU 0 , STD 5 |
| You complete a measurement on a tissue. The results were HU 500 STD. 8. You conclude that the tissue type is? | bone calcium |
| spatial resolution in CT refers to the | ability of the CT scanner to discriminate objects of varying density a small distance apart |
| which of the following is not describing spatial resolution - low contrast resolution -high contrast resolution - detail resolution | low contrast resolution |
| changing the reconstruction algorithm, focal spot size, and the slice thickness will affect | spatial resolution in CT |
| to get the best spatial resolution, the matrix size should be: | the biggest (512x512) |
| contrast resolution in CT refers to the | ability of the scanner to demonstrate small changes in tissue contrast |
| larger slice thickness, and higher mAs will improve: | contrast resolution |
| the fluxation of CT numbers from point to point in an image for a scan is called | noise |
| a larger DFOV, an increase in slice thickness, or in an increase in dose would decrease: | noise in CT |
| decreasing the spatial resolution would equal | larger pixel size |
| increasing the contrast resolution would equal | larger pixel size |
| decreasing patient dose would equal | larger pixel size |
| decreasing noise would equal | larger pixel size |
| increasing the spatial resolution would equal | smaller pixel size |
| decreasing contrast resolution would equal | smaller pixel size |
| increasing patient dose would equal | smaller pixel size |
| increasing noise would equal | smaller pixel size |
Created by:
elliekhughes