Computed Tomography Ultimate 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 Ultimate flashcards as text
A patient has a serum creatinine of 2.8 mg/dL. What is the most appropriate action before administering iodinated contrast?
Answer: Consult with the ordering physician and consider pre-hydration or alternative imaging
Elevated creatinine indicates impaired renal function; the clinical team should assess the risk-benefit ratio and consider IV hydration or alternative modalities.
Which CT technique uses two X-ray tubes operating at different kilovoltage peaks simultaneously?
Answer: Dual-energy CT
Dual-energy CT employs two X-ray sources at different kVp settings (e.g., 80 and 140 kVp) to exploit differences in tissue attenuation based on photon energy.
What is the role of the 'anti-scatter grid' in CT imaging?
Answer: It reduces scattered radiation reaching the detectors
Anti-scatter grids are placed in front of detectors to absorb scattered photons that would otherwise degrade image contrast and quality.
Which contrast injection phase best visualizes hepatocellular carcinoma (HCC)?
Answer: Arterial phase
HCC is hypervascular and enhances avidly during the arterial phase (approximately 25-35 seconds after injection) when hepatic artery flow predominates.
What does ALARA stand for in radiation protection?
Answer: As Low As Reasonably Achievable
ALARA is the guiding principle in radiation protection meaning doses should be kept as low as reasonably achievable while maintaining diagnostic image quality.
Which parameter directly determines the thickness of a CT slice in single-detector row scanners?
Answer: Detector aperture width
In single-detector scanners, slice thickness is controlled by pre-patient and post-patient collimation, which determines the detector aperture width.
A ring artifact on a CT image is most likely caused by:
Answer: A faulty detector element
Ring artifacts are caused by a malfunctioning or uncalibrated individual detector element that consistently records incorrect attenuation values.