Appendicitis is caused by obstruction of the appendiceal lumen leading to bacterial overgrowth and inflammation. CT imaging is used to diagnose appendicitis by identifying signs such as an enlarged appendix over 6mm in diameter, appendiceal wall thickening over 2mm, wall enhancement, periappendiceal fat stranding, and appendicoliths. These imaging findings indicate appendiceal inflammation that could require surgical removal of the appendix.

1. Appendicitis

2. Pathophysiology
• Obstruction of lumen causes diffuse pain
• Intraluminal bacterial overgrowth causes:
– Mucosal breakdown
– Bacterial invasion of appendiceal wall
– Inflammation --> peritonitis --> localized pain
– Perforation
• E. coli, Peptostreptococcus
• B. fragilis, Pseudomonas

3. Technique
• IV contrast - 2cc/kg
– Enhances
inflammatory
processes
• Helical (spiral)
multidetector
technique
• May use oral and/or
rectal contrast

4. Enlarged Appendix
• Enlarged appendix
(> 6mm diameter)

5. Enlarged Appendix
• Enlarged appendix
(> 6mm diameter)
12mm

6. Appendiceal Wall Thickening
• Enlarged appendix
(> 6mm diameter)
• Appendiceal wall
thickening (>2mm)

7. Appendiceal Wall Thickening
• Enlarged appendix
(> 6mm diameter)
• Appendiceal wall
thickening (>2mm)

8. Wall Enhancement
• Enlarged appendix
(> 6mm diameter)
• Appendiceal wall
thickening (>2mm)
• Appendiceal wall
enhancement

9. Wall Enhancement
• Enlarged appendix
(> 6mm diameter)
• Appendiceal wall
thickening (>2mm)
• Appendiceal wall
enhancement

10. Fat Stranding
• Enlarged appendix
(> 6mm diameter)
• Appendiceal wall
thickening (>2mm)
• Appendiceal wall
enhancement
• Periappendiceal fat
stranding

11. Fat Stranding
• Enlarged appendix
(> 6mm diameter)
• Appendiceal wall
thickening (>2mm)
• Appendiceal wall
enhancement
• Periappendiceal fat
stranding

12. Appendicolith
• Seen in 20-40% of
patients

13. Appendicolith
• Seen in 20-40% of
patients

14. Target Structure
• Concentric thickening
of the inflamed
appendiceal wall

15. Target Structure
• Concentric thickening
of the inflamed
appendiceal wall

16. Intraluminal Air

17. Case Review
• Case 12 - 10 year old male with RLQ pain
• Case 15 - 8 year old male with RLQ pain
• Case 26 - 10 year old male with RLQ pain
• Case 27 - 12 year old male with RLQ pain
• Case 43 - 5 year old male with RLQ pain
• Case 65 - 8 year old male with RLQ pain