Real-time US signs of acute appendicitis | |
---|---|
Direct signs | Indirect signs |
Non-compressibility of the appendix  Perforation: appendix might be compressible | Free fluid surrounding appendix |
Diameter of the appendix > 6 mm | Local abscess formation |
Single wall thickness ≥ 3 mm | Increased echogenicity of local mesenteric fat |
Target sign:  Hypoechoic fluid-filled lumen  Hyperechoic mucosa/submucosa  Hypoechoic muscularis layer | Enlarged local mesenteric lymph nodes |
Appendicolith: hyperechoic with posterior shadowing | Thickening of the peritoneum |
Colour Doppler and contrast-enhanced US:  Hypervascularity in early stages of AA  Hypo- to avascularity in abscess and necrosis | Signs of secondary small bowel obstruction |