Scan Protocols Flashcards

For a CT coronary angiography (CCTA) protocol, which heart rate range is generally ideal to minimize motion artifact?

Answer: <65 bpm

Heart rates below 65 bpm allow longer diastolic rest periods, reducing cardiac motion artifact during CCTA acquisition.

When scanning for acute aortic dissection, the scan range should include:

Answer: Chest, abdomen, and pelvis

Aortic dissection can extend from the aortic root to the iliac arteries, so the entire aorta from chest through pelvis must be imaged.

A CT myelography protocol requires which patient preparation step unique to this exam?

Answer: Intrathecal injection of iodinated contrast

CT myelography requires intrathecal (subarachnoid) injection of water-soluble iodinated contrast to opacify the spinal canal.

Which pitch factor would result in the longest scan time for a given scan range?

Answer: 0.5

A lower pitch means the table moves more slowly relative to rotation speed, resulting in more overlap and a longer scan time.

In a CT urography (CTU) protocol, the excretory phase is typically acquired how long after IV contrast injection?

Answer: 5–10 minutes

The excretory (nephrographic) phase of CTU is acquired 5–10 minutes post-injection to allow contrast to opacify and distend the collecting system and ureters.

Which window setting is most appropriate for evaluating acute intracranial hemorrhage on a non-contrast head CT?

Answer: Brain window (WW 80, WL 35)

The brain window (narrow width ~80 HU, level ~35 HU) provides optimal contrast between hyperdense blood and surrounding brain tissue.

For a CT scan of the spine performed to evaluate for disk herniation, which reconstruction kernel is preferred?

Answer: Standard soft tissue kernel

A standard or intermediate soft tissue kernel is preferred for disk and neural structure evaluation, reducing noise while preserving relevant detail.