Lab 8 Flashcards
Which of the following is the current gold standard in imaging for the detection of a PE?
a. Chest x-ray
b. CTPA
c. US
d. VQ scan
b
T/F
One advantage of CTPA over other methods of diagnosing a PE is the higher spatial and contrast resolution.
True
T/F
Beam hardening artifact from the SVC is a limitation of CTPA.
True
How can beam hardening artifact in the SVC be improved/reduced during a CTPA?
1. Dilution of contrast using a saline flush
2. Injecting contrast at a high flow rate and gradually reducing the flow rate during the scan
3. Performing the scan with the patient prone
4. Coaching the patient with breathing instructions
5. Both 1+2
Dilution of contrast using a saline flush
Which of the following is a potential patient dependent limitation during a CTPA study?
a. Patient position
b. Sex
c. Weight
d. Beam hardening artifact from SVC
Beam hardening artifact from SVC
Which of the following is an ideal IV contrast injection flow rate for a CTPA study?
a. 1cc/s
b. 3cc/s
c. 5cc/s
d. 8cc/s
5cc/s
What aspects of the following image makes it so that the image has excellent enhancement?
-Contrast is in the pulmonary arteries only. There is very little contrast in the aorta
-64 slice scanner
-ROI was placed in the pulmonary artery and was triggered at 140 HU
Aside from reminding the patient to remain still, what could the technologist have done to ensure image acquisition occurred at peak pulmonary artery enhancement?
Expiratory imaging
Why is the expiratory phase in imaging recommended during a CTPA
-In cases of Valsalva’s, we get a lower quality image in the pulmonary arteries. Expiration imaging avoids suboptimal PA opacification. During inspiration there is a variable increase in unspecified venous blood from the IVC, briefly diluting contrast entering the SVC.
-Expiratory imaging improves diagnostic quality of CTPA by eliminating transient attenuation artifact
-Showed greater attenuation of the Pulmonary trunk, right + left Pulmonary arteries.
To visualize subsegmental pulmonary emboli, what should the reconstruction slice thickness be?:
a. Less than 1mm
b. Greater than 1mm
c. Greater than 1mm but less than 2mm
d. Between 2 and 5 mm
a. Less than 1mm
Your timing bolus series provides the following graph. If the scanner prep delay is 5 seconds, what would the total scan delay be, to ensure image acquisition occurs at optimal PA opacification?
a. 4 seconds
b. 5 seconds
c. 8 seconds
d. 13 seconds
8 seconds
You end up with the following CTPE scan. An ROI placed in the pulmonary trunk yields a mean HU of 100. Is the scan optimal, yes or no, and why?
No, it is not optimal, the pulmonary trunk is not opacified as much as it should be.
If your opacification was suboptimal despite your total prep delay being accurate, provide 4 other PRACTICAL solutions you would consider to optimize opacification.
Increase the contrast volume
Inject faster
Coach breathing
Try to get a good 18 - 20G IV
Is this study positive for PE?
a. Yes
b. No
Yes
