Computed Tomography (CT) 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 (CT) flashcards as text
Which structure is best evaluated using a 'brain window' setting (W:80, L:40)?
Answer: Gray-white matter differentiation in the brain
A narrow window width centered around 40 HU maximizes contrast between gray matter (~40 HU) and white matter (~30 HU), essential for evaluating brain parenchyma.
What is the primary advantage of iterative reconstruction over filtered back projection (FBP) in CT?
Answer: Reduced image noise at equivalent or lower radiation dose
Iterative reconstruction algorithms model the imaging process and iteratively reduce noise, allowing diagnostic quality images at lower mAs and reduced patient dose compared to FBP.
A CT scan shows a pulmonary nodule measuring 6 mm in a high-risk patient. Per Fleischner Society guidelines, what is the recommended follow-up?
Answer: CT at 6–12 months, then consider CT at 18–24 months
Fleischner Society guidelines recommend CT follow-up at 6–12 months for a 6 mm solid nodule in high-risk patients (smoker, prior cancer), with possible additional follow-up.
What does 'temporal resolution' mean in cardiac CT?
Answer: The minimum time interval the scanner needs to freeze cardiac motion
Temporal resolution in cardiac CT refers to the shortest acquisition time (typically half the gantry rotation time) needed to capture a sharp, motion-free image of the moving heart.
During a CT scan, the technologist notices the patient's heart rate is 85 bpm for a cardiac CT. What is the most appropriate action?
Answer: Administer beta-blocker medication to lower heart rate below 60 bpm if not contraindicated
Heart rates above 65–70 bpm degrade cardiac CT image quality due to motion; beta-blockers are administered (when not contraindicated) to achieve a slower, steadier rate.
What is the primary use of saline flush immediately following IV contrast injection in CT?
Answer: To push the contrast bolus forward and improve vascular opacification while reducing contrast volume
A saline chase pushes residual contrast from the tubing and peripheral veins into circulation, extending the bolus and improving opacification with less total contrast.
On a CT scan of the abdomen, what Hounsfield unit threshold is typically used to identify an acute hemorrhage?
Answer: 55–80 HU
Acute hemorrhage typically measures 55–80 HU on non-contrast CT due to the high protein content of clotted blood, making it hyperdense relative to surrounding soft tissues.