Computed Tomography Knowledge Questions and An Flashcards
7 cards from real Computed Tomography Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Computed Tomography Knowledge Questions and An flashcards as text
Which CT finding is most characteristic of acute appendicitis?
Answer: Appendix diameter >6 mm with periappendiceal fat stranding and wall enhancement
Acute appendicitis classically appears as an inflamed, dilated appendix (>6 mm) with periappendiceal fat stranding and wall hyperenhancement on CT.
What is the purpose of using a higher kVp setting when scanning a bariatric patient?
Answer: To increase penetrating power of the X-ray beam through greater tissue thickness
Higher kVp produces more energetic photons with greater penetrating ability, reducing photon starvation and noise when imaging larger patients with greater tissue attenuation.
On a CT abdomen, a lesion measures -120 HU. What does this attenuation value suggest?
Answer: Fat-containing lesion (lipoma or angiomyolipoma)
Fat has a characteristic negative attenuation of approximately -50 to -150 HU, so a value of -120 HU strongly indicates a fat-containing lesion.
What is the function of the CT gantry?
Answer: Contains the rotating X-ray tube and detector array that surrounds the patient
The gantry is the large ring-shaped housing that contains the X-ray tube and detector array, which rotate around the patient during data acquisition.
Which condition is best diagnosed using CT pulmonary angiography (CTPA)?
Answer: Pulmonary embolism
CTPA is the gold standard for diagnosing pulmonary embolism, demonstrating filling defects within pulmonary arteries during the pulmonary arterial phase.
What does 'window leveling' (adjusting the level/center) primarily affect in a CT image?
Answer: The overall brightness or density of the displayed image
The window level (center) sets the midpoint of the displayed HU range, shifting the image brighter or darker without changing the range of visible values.
In CT, what is the significance of a 'negative predictive value' of 99% for ruling out pulmonary embolism with CTPA?
Answer: If CTPA is negative, there is a 99% chance the patient truly does not have PE
A 99% negative predictive value means that a negative CTPA result is highly reliable for excluding PE, with only a 1% chance of a false-negative result.