Contrast Media Flashcards
7 cards from real ARRT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Contrast Media flashcards as text
Which premedication regimen is most commonly recommended for elective contrast administration in patients with a prior mild allergic-like contrast reaction?
Answer: Oral prednisone 50 mg at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before
The ACR-recommended premedication protocol for non-emergent cases includes oral prednisone at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before.
In CT colonography (virtual colonoscopy), which type of contrast material is used to 'tag' residual stool and fluid?
Answer: Oral barium and/or dilute iodinated contrast ingested before the exam
Fecal tagging uses oral barium and/or iodinated contrast ingested in the days before CTC to label residual stool and fluid, allowing software subtraction.
What Hounsfield unit (HU) threshold is typically used in bolus tracking software to trigger CT acquisition during contrast-enhanced aortic studies?
Answer: 150–200 HU
Most institutions set the bolus tracking trigger threshold between 150–200 HU in the aorta to ensure adequate arterial opacification before scan initiation.
What is the primary advantage of using a saline flush (chaser bolus) after IV contrast injection in CT?
Answer: It pushes the contrast bolus forward, improving vascular enhancement and reducing total contrast dose
A saline flush displaces residual contrast from the IV tubing and arm veins into central circulation, sharpening the bolus and potentially allowing dose reduction.
A CT technologist notices that a patient's IV access site shows swelling and the patient reports pain during injection. The power injector shows a pressure increase. What is the most likely complication?
Answer: Contrast extravasation into subcutaneous tissues
Swelling, pain, and increased injector pressure at the IV site are classic signs of contrast extravasation, requiring immediate cessation of injection.
For a pancreatic protocol CT, which phase is most critical for detecting hypervascular pancreatic neuroendocrine tumors?
Answer: Late arterial (pancreatic parenchymal) phase at 40–50 seconds
Pancreatic neuroendocrine tumors are hypervascular and enhance most conspicuously during the pancreatic parenchymal phase (approximately 40–50 seconds), when the pancreas peaks in enhancement.
Which patient factor most directly increases the risk of contrast extravasation injury severity?
Answer: Large volume of high-concentration contrast extravasated under high pressure
Large volumes of high-concentration contrast extravasated at high pressure cause greater tissue injury due to osmotic and volume effects on surrounding soft tissue.