| Question 1: An artifact manifesting itself as a small ~1 mm discontinuity in the patient’s skin line and the CT couch/table observed in the sagittal or coronal planes is likely: |
| Reference: | “Computed Tomography: Principles, Design, Artifacts, and Recent Advances” Jiang Hsieh SPIE Press 2015 |
| Choice A: | A patient induced artifact, and the issue would probably not be seen in another patient. |
| Choice B: | An issue with the scanner, and the issue would likely be seen in another patient. |
| Choice C: | An issue with the CT detectors that would appear as a ring artifact in the axial plane. |
| Choice D: | An issue with the patient’s breathing between axial bed positions causing a discontinuity along the patient’s body. |
| Question 2: Dirt present on the bowtie filter of a CT scanner may only show up on some patient scans because: |
| Reference: | “Computed Tomography: Principles, Design, Artifacts, and Recent Advances” Jiang Hsieh SPIE Press 2015 |
| Choice A: | As the x-ray tube and detectors get warmed up during a day of scanning, issues related to small dirt particles on the bowtie filter become less and less noticeable. |
| Choice B: | Dirt will commonly move around to different positions on the bowtie filter meaning for some scans it may be in a less or more artifact producing location. |
| Choice C: | CT scanners have different bowtie filters. The dirt will only usually be present on one filter, so if different filters are used for different patients, the dirt induced artifact will only affect some patients. |
| Choice D: | Since the signal level obtained by the detectors is larger for larger patients, the small error introduced by the dirt usually means we see these artifacts only on relatively small patients |
| Question 3: In CT, following ACR accreditation guidelines, a scanner may be used with a known artifact in a full capacity: |
| Reference: | ACR 2017 QC Manual, page 76. |
| Choice A: | If is determined by a CT physicists to not mimic a pathology for head scanning, which is where artifacts usually mimic pathology. |
| Choice B: | If it is determined by the field service engineer to mimic a pathology for head scanning, which is where artifacts usually mimic pathology |
| Choice C: | If it is determined by a radiologists not to mimic a pathology for head scanning, which is where artifacts usually mimic pathology. |
| Choice D: | If it is addressed within 30 days and a radiologists determines it is subclinical. |
| Question 4: In CT, a scanner with a known artifact observed for routine head exams would most likely also be present in which of the following exams? |
| Reference: | “Computed Tomography: Principles, Design, Artifacts, and Recent Advances” Jiang Hsieh SPIE Press 2015 |
| Choice A: | Biphasic liver exam |
| Choice B: | Thoracic spine exam |
| Choice C: | CTA head exam |
| Choice D: | Ankle/Foot exam |
| Question 5: Dielectric (“standing wave”) effects may be decreased using: |
| Reference: | Body MR Imaging: Huang SY, Seethamraju RT, Patel P, Hahn PF, Kirsch JE, Guimaraes AR. Body MR Imaging: Artifacts, k-Space, and Solutions. Radiographics. 2015 Sep-Oct;35(5):1439-60. |
| Choice A: | Lower field (B0) strengths |
| Choice B: | Multi-Transmit B1+ Excitation |
| Choice C: | Longer Echo-Times |
| Choice D: | A & B only |
| Choice E: | B & C only |
| Question 6: “PROPELLER” and “Radial” are two k-space trajectories that would be considered most effective at minimizing: |
| Reference: | Zaitsev M, Maclaren J, Herbst M. Motion artifacts in MRI: A complex problem with many partial solutions. J Magn Reson Imaging. 2015 Oct;42(4):887-901. |
| Choice A: | Aliasing artifacts. |
| Choice B: | Acquisition time. |
| Choice C: | Motion artifacts. |
| Choice D: | Susceptibility artifacts. |
| Question 7: Susceptibility induced distortion in 2D EPI based DWI acquisitions are most prominent in the: |
| Reference: | Body MR Imaging: Huang SY, Seethamraju RT, Patel P, Hahn PF, Kirsch JE, Guimaraes AR. Body MR Imaging: Artifacts, k-Space, and Solutions. Radiographics. 2015 Sep-Oct;35(5):1439-60. |
| Choice A: | Phase encoding direction. |
| Choice B: | Frequency encoding direction. |
| Choice C: | Magnet isocenter. |
| Choice D: | Slice encoding direction. |
| Question 8: What is the cause of the skin line processing error in DBT? |
| Reference: | Imaging With Synthesized 2D Mammography: Differences, Advantages, and Pitfalls Compared With Digital Mammography, Samantha P. Zuckerman, Andrew D. A. Maidment, Susan P. Weinstein, Elizabeth S. McDonald, and Emily F. Conant American Journal of Roentgenology 2017 209:1, 222-229 |
| Choice A: | Low kVp used in DBT. |
| Choice B: | High kVp used in DBT. |
| Choice C: | Low detector dose. |
| Choice D: | High detector dose. |
| Choice E: | Use of Aluminum filtration in DBT. |
| Question 9: What is the best method to reduce metallic halo artifact in DBT imaging when using filtered back projection as your reconstruction process? |
| Reference: | Voting Strategy for artifact reduction in digital breast tomosynthesis, Tao Wu, Richard A. Moore and Daniel B. Kopans, Medical Physics 33(7), 2461 (2006) |
| Choice A: | Projection Segmentation Method. |
| Choice B: | Maximum Contribution Deduction. |
| Choice C: | One Step Classification. |
| Choice D: | Iterative Classification. |
| Question 10: What is one possible reason for the loss of conspicuity of small calcifications in s2D images? |
| Reference: | : Imaging With Synthesized 2D Mammography: Differences, Advantages, and Pitfalls Compared With Digital Mammography,Samantha P. Zuckerman, Andrew D. A. Maidment, Susan P. Weinstein, Elizabeth S. McDonald, and Emily F. Conant, American Journal of Roentgenology 2017 209:1, 222-229 |
| Choice A: | High kVp reduces contrast of the calcium. |
| Choice B: | Image noise reduces the contrast of the calcification. |
| Choice C: | Binning of detector elements averages out the calcification. |
| Choice D: | Edge enhancement causes loss of conspicuity. |
