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20 Cards in this Set
- Front
- Back
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Which of the following would eliminate a ring artifact?
a. recalibration of the detector elements b. removal of metal c. decreased matrix d. increased mAs |
a. recalibration of the detector elements
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____________ in the image is a possible manifestation of patient motion.
1. ghosting 2. blurring 3. streaks a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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CT x-ray tube arcing can occur because of ___________ the x-ray tube
1. impourities in the oil outside 2. tungsten gas inside 3. tungsten solids in the oil inside a. 1 only b. 1 & 2 c. 2 only d. 2 & 3 |
b. 1 & 2
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If an algorithm to correct for the cupping artifact is applied too aggressively to the data for a head image, the _____________ of the image would be too bright.
1. top and bottom 2. center 3. edges a. 1 only b. 2 only c. 3 only d. 1 & 3 |
b. 2 only
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Which of the following may occur if the patient's arms are placed at their sides during a chest exam if the scan field-of view is 33cm?
1. beam hardening 2. out-of-field artifact 3. cone beam artifact a. 1 only b. 1 & 2 c. 2 only d. 3 only |
b. 1 & 2
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Which of the following could allow for a reduction of partial volume artifact while not increasing the appearance of noise in the image?
a. increasing slice thickness while decreasing kVp b. decreasing slice thickness while decreasing mAs c. increasing slice thickness while increasing mAs d. decreasing slice thickness while increasing mAs |
d. decreasing slice thickness while increasing mAs
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A variation in which of the following will affect the hardening of an x-ray beam?
1. tissue density 2. tissue thickness 3. kVp a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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In which direction are streaks from the edge gradient effect oriented?
a. radially outward from the center of the image b. parallel to the direction of the sharp density difference interface c. perpendicular to the direction of the sharp density difference interface d. in a herringbone pattern across the image |
b. parallel to the direction of the sharp density difference interface
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On a CT image of the brain a cupping artifact would appear brighter:
a. at the anterior and posterior aspects of the brain b. at the periphery of the brain c. immediately around dense structures d. in the center of the brain |
b. at the periphery of the brain
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Which of the following may be a result of partial volume averaging?
1. decreased sharpness of edges 2. inaccurate CT numbers 3. ghosting of tissue boundaries a. 1 only b. 2 only c. 1 & 2 d. 3 only |
c. 1 & 2
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The service angineer should be notified about which of the following?
1. frequent bad streaks on the inferior slices of head scans 2. a consistent circle on the images 3. frequent bad streaks throughout the entire image a. 1 only b. 2 only c. 3 only d. 2 & 3 |
d. 2 & 3
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How would the artifact from a faulty detector element appear on a localizer image?
a. a line perpendicular to the long axis of the patient table b. it depends on the orientation in which the localizer image is performed c. a circle in the center of the image d. a line parallel to the long axis of the patient table |
d. a line parallel to the long axis of the patient table
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Which of the following is TRUE as the slice thickness is decreased?
a. partial volume artifacts increase while edge gradient artifacts decrease b. partial volume artifacts and edge gradient artifacts decrease c. partial volume artifacts decrease while edge gradient artifacts increase d. partial volume artifacts and ege gradient artifacts increase |
b. partial volume artifacts and edge gradient artifacts decrease
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A(n) _____________ artifact is a streak artifact which arises from a high spatial frequency interface between tissues with a great difference in density
a. tube arcing b. edge gradient c. cone beam d. ring |
b. edge gradient
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Which of the following would decrease the effects of beam hardening artifacts?
1. increased kVp 2. increased mAs 3. increased scan time a. 1 only b. 1 & 2 c. 2 only d. 3 only |
a. 1 only
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Which of the following strategies would NOT help us differentiate possible pathology from a partial volume artifact?
1. inspection of adjacent slices 2. collect additional thinner slices through suspicious region 3. rescan and decrease pitch (without changing slice thickness) a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
c. 3 only
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Which of the following strategies minimizes beam hardening artifact from dense contrast media?
1. the contrast solution can be diluted 2. the scan can be performed with a slight delay 3. the scan can be performed in the opposite direction a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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Tube arcing might cause ____________ on the images.
a. star-like artifacts at the edges b. an increased appearance of noise c. shading and inaccurate CT numbers d. an appearance of a circle or ring |
b. an increased appearance of noise
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Which of the following will have the least likelihood of producing edge gradient artifacts?
a. thin slices with full scan b. thick slices with partial scan c. thin slices with partial scan d. thick slice with full scan |
a. thin slices with full scan
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Which of the following strategies will minimize metal artifacts?
1. remove as much metal from the patient as possible 2. orient slices such that the metal is avoided if possible 3. inspect the localizer for any metal on the patient and remove any metal or avoid imaging it as much as possible a. 1 only b. 2 only c. 3 only d. 1, 2 & 3 |
d. 1, 2 & 3
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