1. University of Ottawa Diagnostic Radiology OSCE April 12th, 2004
Station #36
University of Ottawa Diagnostic Radiology OSCE April 12th, 2004

2. 10 Cases Use “Page Up” and “Page Down” keys to view images.
Questions and images are together on the same slide.

3. Case 1: What is the source of the artifacts (arrows)?
What could you do to remove this type of artifact?

4. Case 2: What is the source of the artifact (arrows)?
Based on the nature of the artifact, what is the phase encode direction in each image, and why?

5. Case 3:
On either side of the kidneys, the image is alternately bright and dark. What is this artifact called?
How could you minimize this artifact?

6. Case 4: What is the source of the artifact (arrows)?
Based on the nature of the artifact, what is the phase encode direction, and why?
How could you minimize this artifact?

7. Case 5: What is the source of the artifacts in these images?

8. Case 6: Assume that the DSA image is truth.
TOF MRA
CONTRAST MRA
DSA
Case 6: Assume that the DSA image is truth.
Why does the carotid artery appear occluded on the TOF MRA? Note that the original images were acquired axially, but reformatted for display in a sagittal orientation.
Why is this artifact not observed in the contrast enhanced MRA?

9. Case 7:
What is responsible for the banding artifact within the liver?
How could you minimize this artifact?

10. Case 8:
These images were acquired with a gradient-echo pulse sequence. The lower images at the level of the skull base have large voids. Why?

11. Case 9:
What type of artifact is responsible for the ringing around sharp edges in this image (arrows)?
How could it be removed?

12. Case 10:
What is the source of the stripe artifact in these two images?
What determines the angulation of the stripes?

13. End of Station