Appendicitis ultrasound
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Appendicitis On the Web |
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American Roentgen Ray Society Images of Appendicitis |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Ultrasounds are a useful tool for diagnosing appendicitis. There are some limitations to the information provided by ultrasounds, such as ultrasonographic images of the iliac fossa show no abnormalities despite the presence of appendicitis. Whenever available, CT scans are preferred over ultrasounds for diagnosing appendicitis.
Use as a Diagnostic Tool
- Ultrasonography and Doppler sonography provide useful means to detect appendicitis, especially in children.
- In some cases (15% approximately), however, ultrasonography of the iliac fossa does not reveal any abnormalities despite the presence of appendicitis.
- This is especially true of early appendicitis before the appendix has become significantly distended and in adults where larger amounts of fat and bowel gas make actually seeing the appendix technically difficult.
- Despite these limitations, in experienced hands sonographic imaging can often distinguish between appendicitis and other diseases with very similar symptoms such as inflammation of the lymph nodes near the appendix or pain originating from other pelvic organs such as the ovaries or fallopian tubes.
Diagnostic Comparison to a CT Scan
- According to a systematic review from UC-San Francisco comparing ultrasound vs. CT scan, a CT scan is more accurate than ultrasound for the diagnosis of appendicitis in adults and adolescents.
- CT scan has a sensitivity of 94%, specificity of 95%, a positive likelihood ratio of 13.3 (CI, 9.9 to 17.9), and a negative likelihood ratio of 0.09 (CI, 0.07 to 0.12).
- Ultrasonography had an overall sensitivity of 86%, a specificity of 81%, a positive likelihood ratio of 5.8 (CI, 3.5 to 9.5), and a negative likelihood ratio of 0.19 (CI, 0.13 to 0.27).[1]