CT Imaging Procedures - Scan Parameters

The abrupt starting and stopping of the patient table during axial scanning can result in: A. Increased patient dose B. Motion artifact on the images C. Decreased scan time D. Decreased spatial resolution from interpolation

B. Motion artifact on the images

Which of the is a potential reason to DECREASE the IV contrast volume during a CT scan: A. Angiographic scanning B. Pediatric scanning C. Slow scanner speed D. Long scan length

B. Pediatric scanning

One reason for decreasing the IV injection rate during CT scanning is? A. High-speed scanner (16 rows or more) B. Poor IV catheter patency C. Angiographic scanning D. Geriatric imaging

B. Poor IV catheter patency

Can you power inject a jugular line?

No extravasation in the neck could cause occlusion of the arterial supply to the brain and induce symptoms of stroke

The scan should start

What happens in this bolus-tracking when the 110 HU threshold is crossed

Compared to a 1 mm reconstructed slice, a 5 mm reconstructed slice would usually result in what change? Assume all other variables remain constant. 1. Decreased Noise 2. Decreased Spatial Resolution 3. Decreased Patient dose

1 and 2 only. Decreased Noise and Decreased Spatial Resolution Reconstruction slice thickness have no effect on the patient dose

A new CT protocol requires scanning the liver at exactly 25 seconds after initiating IV contrast injection. This can be accomplished by which scan timing method. 1. Scan Delay time 2. Test Bolus 3. Bolus Tracking

1 only. Scan delay time

Advantages of helical scanning over axial scanning include: 1. Decreased scan time 2. Decreased patient dose 3. Increased spatial resolution

1&2 only. Decreased scan time and Decreased patient dose

During the monitoring phase of bolus tracking you see several images showing no contrast at all. Possible explanation include: 1. The contrast injection was never initiated 2. The contrast has infiltrated 3. The saline and contrast syringes were loaded backwards

1, 2 and 3

Which contrast injection method would be useful for precisely timed angiographic procedures? 1. Scan delay time 2. Test Bolus 3. Bolus Tracking

2 and 3 only. Test Bolus and Bolus Tracking

The first phase of IV contrast enhancement for most organs is the: A. Portal venous phase B. Arterial phase C. Delayed phase D. Capillary phase

B. Arterial phase

What is the purpose of warming intravenous contrast prior to injection? A. Decreased Viscosity B. Increased Radiopacity C. Decreased Chemical toxicity

A only. Decreased Viscosity Decreasing viscosity decrease the risk of extravasation

Which of these venous access devices are sometimes labeled for CT power injection? A. Central lines (port) B. Dialysis catheters C. Jugular lines

A. Central lines (port)

Consider a patient admitted to the emergency department for flank pain, hematuria, and suspected renal stone. CT imaging for the initial assessment of the collecting system should be performed during which phase pf contrast enhancement? A. Non-contrast B. Excretory phase C. Arterial phase D. Portal Venous Phase

A. Non-Contrast Renal stones appear white and the contrast also appears as white. The use of contrast could disguise the presence of renal stones.

Displayed CT images are processed to display a specific amount of anatomical data in each image. This is the: A. Reconstruction slice thickness B. Reconstruction slice interval C. Acquisition slice thickness D. Beam width

A. Reconstruction slice thickness

The acquisition slice thickness used during a scan is determined by the technologist. The acquisition thickness refers to: A. The thickness of activated detector rows B. The thickness of anatomical data averaged into each image C. The total width of the x-ray beam D. The space between adjacent slices

A. The thickness of activated detector rows

Intravenously injected contrast can be viewed exiting organs during which phase of enhancement? A. Venous Phase B. Arterial Phase C. Delayed Phase D. Equilibrium Phase

A. Venous

The average flow rate recommended for venous phase imaging of the abdomen is: A. 1 ml per second B. 3 ml per second C. 5 ml per second D. 10 ml per second

B. 3 ml per second

Increasing the reconstruction slice thickness results in: A. Visualization of more anatomy with increased spatial resolution B. Visualization of more anatomy with decreased spatial resolution C. Visualization of less anatomy with increased spatial resolution D. Visualization of less anatomy with decreased spatial resolution

B. Visualization of more anatomy with decreased spatial resolution

Which phase of IV contrast enhancement is ideal for initial imaging of intracranial hemorrhage? A. Venous phase B. Arterial phase C. Delayed phase D. Non-contrast

D. Non-contrast Blood and contrast both appear white

Which of the following is NOT a common reason to use contrast enhancement during CT scanning? A. Differentiate between normal tissues B. Differentiate between normal tissues and abnormalities C. Add visual contrast to the images D. Reduce patient radiation exposure

D. Reduce patient radiation exposure The use of contrast does allow the technology to reduce the technique or make any other change that might reduce the patient dose but the use of contrast does NOT reduce the patient radiation exposure

No

Does this image include any contrast enhancement?

This phase of contrast enhancement in the abdomen peaks at 50-60 seconds after initiating IV contrast injection.

Portal venous phase

Display field of view

The major difference between these two images is the?

Slice thickness (could also be caused by using a smoothing algorithm)

The major difference in these two images: A. Slice interval B. Slice thickness C. Display field of view D. Scan Type

What is the primary reason for monitoring intraluminal pressure during IV contrast injection?

To avoid contrast extravasation