Teaching Case

An abdominal plain film was normal. Ultrasound demonstrated an uncompressible appendix with anteroposterior measurements consistently 10mm. Computed tomography scanning demonstrated an enlarged appendix with fat stranding. Appencitis was diagnosed and confirmed by surgery.

Abdominal plain films are most frequently normal, but can demonstrate appendicolith. Ultrasound demonstrates a non-compressible bowel loop attached to apical caecum with a termination as a blind pouch corresponding to the enlarged appendix, with anteroposterior diameter measurements consistently 6mm or greater. If an appendicolith is identified within an appendix of any size, the examination is always considered positive for appendicitis. CT signs of appendicitis can be divided into direct and indirect signs. Direct signs are an enlarged (>6mm in diameter), unopacified appendix, appearing tubular or circular, and possibly containing an appendolith (specificic for appendicitis but not frequent). Indirect signs are focal caecal apical thickening, the arrowhead sign of appendicitis (contiguous spread of appendiceal wall inflammation into the caecal apex results in a triangular-shaped space between the thickened apical walls), the caecal bar sign (a curved soft tissue bar of density interposed between the caecal lumen and the proximal appendicolith), right lower quadrant abdominal fat stranding, lateroconal fascial thickening, abcess, phlegmon, and diffuse caecal wall thickening.