Pitfalls in CT Colonography

Targeted CE per ARRT’s Discipline, Category, and Subcategory classification for enrollments starting after February 8, 2023:
[Note: Discipline-specific Targeted CE credits may be less than the total Category A credits approved for this course.]

Computed Tomography: 3.25
Procedures: 3.25
Abdomen and Pelvis: 3.25

Registered Radiologist Assistant: 2.25
Procedures: 2.25
Abdominal Section: 2.25

Outline

1. Introduction
2. CT Colonographic Technique
3. Technical Errors
   1. Patient Preparation
      1. Stool
      2. Residual Fluid
   2. Distention
      1. Underdistention
      2. Spasm
      3. Perforation
   3. Scanning
      1. Artifacts
      2. Stair-Step Artifacts
      3. Image Noise
4. Pitfalls in Evaluation
   1. Evaluation Technique
      1. Values for 2D Imaging
      2. Three-dimensional Shine-Through Artifacts
      3. Three-dimensional Rendering
   2. Perception Errors
      1. Technique
      2. Underdistention
      3. Residual Fluid
      4. Blind Spots
   3. Interpretation Errors
      1. Content
      2. Intrinsic Lesions
      3. Extrinsic Lesions
   4. Computer-aided Detection
5. Conclusions

Objectives

Upon completion of this course, students will:

1. be able to identify the pitfalls of MDCT in CT colonography
2. understand how haustral folds interfere with CT colonography evaluation
3. list factors affecting the diagnostic sensitivity in CT colonography
4. know advantages of MDCT scanners over single-row detector scanners in CT colonography
5. comprehend the effect of image noise on CT colonography evaluation
6. have learned essential patient preparation for CT colonography
7. understand how gas is used to distend colonic segments
8. understand the importance of acquiring images in both prone and supine positions
9. be able to identify different artifacts in CT colon images
10. understand indications for oral vs. intravenous contrast administration in CT colonography
11. know how to interpret residual stool in the bowel on CT images
12. know how to detect residual stool in the bowel on CT images
13. know how to detect residual fluid
14. recognize differences in prone vs. supine CT images of the colon
15. learn about the effect of gravity on sensitivity and specificity
16. know characteristics of colonic segments
17. recognize the consequences of underdistention
18. know how to differentiate spasms from a collapsed colonic segment
19. be able to identify colonic wall perforations
20. recognize the effect of respiratory artifacts in CT colonography
21. understand the cause and appearance of the stair-step artifact
22. know how to differentiate image noise from IBD
23. comprehend dose considerations in CT colonography
24. learn about the effects of metal artifacts in CT colonography
25. understand the usefulness of a wide window setting in CT colonography
26. understand the usefulness of a narrow window setting in CT colonography
27. know how to detect a polyp
28. understand the advantages and pitfalls of the “fly through” technique
29. know how to evaluate 2D planar and 3D reconstructed images of the colon
30. learn the pitfalls of underdistention of the colon and how to minimize them
31. learn the pitfalls of residual fluid of the colon and how to minimize them
32. know how to identify blind spots and overcome their pitfalls
33. learn how to characterize a polyp
34. know how to characterize residual stool and fecal-impacted diverticula
35. know how to identify and characterize gas bubbles in the colonic lumen
36. know how to differentiate stenosis from a collapsed colonic segment
37. comprehend the importance of evaluating both 2D planar and 3D surface reconstructions
38. be familiar with detection and interpretation of diverticula
39. identify intrinsic vs. extrinsic lesions
40. understand the utility of CAD in CT colonography